Author Topic: "XT" tantan FM08 29er build  (Read 13689 times)

sclyde2

"XT" tantan FM08 29er build
« on: August 21, 2019, 06:14:40 PM »
Build is underway, but now waiting on brakes, bottom bracket and wheels.

This frame will complete the transformation of my 3 bike garage into chiners:
1. Hardtail - mainly for commuting - 2014 xmiplay fm057
2. FS XC race bike - 2018  hongfu FM058
3. Trail bike - for everything else - tantan FM08

The new trail bike is replacing my last 26er, a 160/155 travel Titus el guapo.  I found that the kind of riding I do doesn't warrant a 150mm+ bike, so I am aiming for around 140mm travel, maybe a bit less on the rear.  Despite it having more travel than I want/need,  I have gone for the FM08 as it appears that I can configure it to how I want it.  With its BB being higher than I prefer, I can short-shock it (reduce the eye to eye and stroke by about 5mm) and put a shorter-than-150mm fork on it, and get to the ride height, geometry and travel that I am aiming for.

I usually spec my bikes with the higher end stuff, usually going for xtr, xx1, 240s hubs etc.  This time around, I am taking a more bang-for-buck approach, and choosing a lot of parts from a level down, a lot of Shimano XT - hence the "XT". 

The initial build will be a mix of some new parts and some old parts scavenged off the el guapo.

Initial spec:
-Tantan FM08 29er medium gloss
-2019 Pike RCT R.  The one with the remote lockout.  initially set at 130, plan to change to 140
-RS monarch RT3 rear shock 200x50 (around 8 years old, but minimal use)
-Eiecarbon wheels - 350 hubs, 30mm internal width rims.  2.35 Schwalbe racing Ralphs, initially with tubes.
-Shimano 11 speed drivetrain
-my old non-boost xtr crank initially.  Might not enough have clearance for an oval ring, so will start round.  Might have to get another crank to get the boost chainline and better clearance for an oval ring
-Shimano brakes
-Hope screw-together pf41 BB
-Initial Cockpit from spare parts - rigid post, 65mm stem, 711mm hbar

I'll put up a more detailed spec list, with most part weights, after the build is complete - I hope to be riding this in about a week and a half from now.

Not sure how heavy this bike will end up, but if it is around 12.5kg in "final" configuration (see changes below), I'll be happy.  The initial configuration (above) will likely be closer to 12kg, as it has a rigid post and xc tyres.

Build notes so far:
* Frame was delivered with a headset installed.  With all headset parts (incl crown race, but not starnut/topcap), and all shock bolts (but no shock), der hanger (but no rear axle), the frame weighed in at 2.71kg.  Similar sized headsets appear to weigh around 110g, so the frame would likely very close to 2.6kg without the headset.  Which I think is Goldilocks "just right'.  Supplied axle weighed 83g.
* The cable guide bolts were too long, one in particular.  Just like supermoto65 found.  The bolts are so long they touch the fork steerer.  I had to cut one down.
* The cable guides for the shift cable are configured as cable stops at each end of the down tube.  As I prefer full length cable outer, I drilled out the one near the BB (didn't have to drill out the other end guide near the head tube, as there was a spare full sized routing at the cable guide).  As this configuration leads to cable rattling inside the frame, I put Capgo noise protection on the cable - get it, it works.
* Front shock mount measured 31.85.  With the 2 included (heavy) 5mm spacers, it looks like they intended it to suit 21.85mm shock hardware, which fit quite nicely.  21.85 was a bit loose on the rear shock mount, but it is snug with 22.2 installed.  Luckily I had the right sized hardware in my spare parts.  I used solid bush hardware front and rear.  I actually have a 22.2mm RWC roller bearing kit, which would be a good idea to use on the rear mount (as it rotates a lot), but will make sure everything is rattle free first, or wait until I get a "proper" shock before i put some roller bearing shock hardware on.
* The shock bolts don't appear to be a very good design or quality.  I'd be surprised if I don't bend them - will request some spares.  The other metal parts (bolts etc) on the frame seem to be better quality/design
* My old shock is off an old 2:1 leverage xc bike, with damping to match (i.e. 'L').  So it will be severely underdamped on this FM08 frame.  The air spring volume will probably be too low too.  I expect it to be a bit wallowy, and I will probably run it with a lot of sag with that shock - upside is that this will give me the lower ride height I am looking for.  I will probably run it with the "floodgate" on to give it some platform.  Depending on how the geometry works out, I'll likely source a 200x57 manitou mcleod shock and shorten it to around 195x52 (or shorten a 210x55 to 205x50).
* In my experience, Tantan is the first Chinese supplier that stuck to their promised timeframes.  Well done.

I expect the wheel shipment and the part shipment (brakes, BB) will get here in about a week.

After I do a few test rides, the main priority is to get the geometry "right".  Head angle, seat tube angle, bottom bracket height. I think a BB height around 340, head angle around 66 is my initial target.  I am guessing a 140mm fork with a 195mm e2e (or a 205mm e2e in the other flip chip position) will get me there.  Before I do any of this, I'll see how I go with 130/200 fork/shock first (it'll almost certainly be a bit high and steep).

Similarly high priority is getting the stem length right.  I'm guessing that 50mm will be a bit more appropriate than the 65mm.

After that, the imminent upgrades remaining:
* Air shaft for fork to get 140mm travel
* Newer better more appropriate rear shock (see above)
* ~2.5" front tyre, probably a maxxis dhf
* Dropper post
* If necessary, a new crank, to get an oval ring to fit.  I am all in on oval rings on my other bikes, and it is working out really really well, so this is high priority

My next post will be when the bike is built, hopefully within the next 10 days.

See photos of build progress (which is now stalled until stuff arrives).  Photo of frame weight includes headset parts and der hanger, and includes plastic shock spacer (for shipping).  Shock spacer weighed 29g, so frame+headset would be 2711g.
see vendors photo of wheels. straight pull centrelock 350 boost hubs, 28 pillar bladed spokes, brass nipples, assymetric 30mm internal rims.  Weight will increase as I am putting a steel Shimano freehub on it.
« Last Edit: August 21, 2019, 06:24:35 PM by sclyde2 »



sclyde2

Re: "XT" tantan FM08 29er build
« Reply #1 on: August 21, 2019, 06:15:08 PM »
Wheels arrived yesterday. 

Build notes:
- Wheel weight: On my scale they were 2g lighter than EIECarbon's scale, at 1544g.  When i subbed in a steel shimano freehub and 36T ratchet, they gained 58g - yeah, those steel freehubs are heavy, but i wont have to worry about an alloy freehub getting chewed up.  So, pre-taping, the wheels are now 1602g.
- the rims are A29C30D28.  Apparently 38.5/30.5 outer/inner.  I measured 38.3/30.3.  Yes, 4mm wide lips.  I put 30mm stans yellow tape on - barely wide enough.  I found some tubes, a heavier one for the rear - 141g/232g F/R.  The tyres (last year's model Racing ralph 29x2.35 speed) totalled about 1600g (814 and 787).  Hardest ever tyre/rim combo to get the tyre on - broke 3 tyre levers.  The cracking noises when the beads seated were the loudest i've heard.
- prior to mounting the tyres, I checked the wheels trueness and checked tensions (Not all spokes, just interested in the general levels).  On my park tension meter, I usually go up to just under 15 on the high tension side for this size spoke, which I believe equates to a tension just on 130.  The front was dead straight, with a high side tension around 12, low side around 10.  Rear wasn't quite as perfectly true (but still probably straighter than if usually aim for), and tensions were remarkably similar, at just under 11 and just over 10.  Seems a bit low.  With the tight tyres now on, these tensions will be lower now - will check.  Might put half a turn onto the rear wheel spokes.
- with wheels on the bike, i checked the bottom out.  I unbolted the rear shock's front mount, and pushed the bike down as far as it would go.  The first thing to hit was the swing link's crossbrace contacting the frame - see photo of this.  as this point, the rear tyre was getting pretty close to the seat-tube, but still a few mm away - see photo.  a tall rear tyre might hit the seat-tube first.  at this point, the eye-eye measurement, from front shock mount to rear '200' mount was 131mm - see photo.  I probably should've measured to the '210' mount (as that position is the one closest to getting contact e.g. if a 200x57 shock was used), but i had enough trouble juggling the flip chip parts when installing the shock, so didnt want to unbolt the shock's rear mount.
- as pictured, with the XC tyres pumped up pretty hard, the Pike at 130mm, and a standard rear shock (i.e. 200 e2e shock in the 200 position), the BB height seems to be around 340-342mm.  Will need to double-check this measurement on flatter ground.
- bit worried about the internal cable routing for a dropper post.  i don't plan to get a dropper until after the bike is built.  but, after the BB is pressed in, it might be difficult to route the dropper cable. as a stop-gap, i am thinking about putting my old reverb (non-stealth) on - it is a 30.9 so would have to get a shim.
- saddle to bar measurements are a bit shorter than expected.  i figure it is the steep seat tube.  got the saddle as far back on the rails as possible, but i think the bike really needs to be slackened out a bit.  gonna hold off purchasing the long air shaft for the fork until i ride it first (just in case i decide to go to 150mm instead of my current intention to go to 140mm).
- current measurements still suggest i should get a 200x57 shock and short shock it (reduce both e2e and stroke).  The proof will be in the riding though.  Mcleod shocks are apparently easy to short shock, 1.25mm at a time.  thinking 3.75mm shorter, to about 196x53, which, at the leverage ratio of 3.0-3.2 around top out, should drop the rear end by about 12mm.  should get the bike to around 66/74.5/340 HA/SA/BBH with 140/140 F/R travel.  The other alternative is to get a 'metric' 210x55 shock instead (and use the other flip chip position) - it seems like the metric versions of the mcleod are better with updated internal features, but they arent freely available yet, and no good deals are available on those (yet).  I am not interested in other shocks, as i don't think they are as easily short shocked.
- shipment of bottom bracket and brakes should arrive tomorrow.

New bike day is imminent.  However, heavy rain is expected later this week, and at the start of the weekend.  not only do i have no intention of taking a new bike on muddy trails, around here it is not considered a good idea (trails is this area aren't built to cope with people riding on them when waterlogged).
« Last Edit: August 27, 2019, 09:49:02 PM by sclyde2 »

sclyde2

Re: "XT" tantan FM08 29er build
« Reply #2 on: August 21, 2019, 06:15:29 PM »
Brakes and bottom bracket arrived a couple days ago.

After a few issues with a few (tiny) brake parts, i finally assembled it tonight.

Initial build
Tantan FM08 frame medium 17.5" glossy
~2011 model rockshox monarch 200x51 shock LL tune, standard volume
2019 pike rct r, at 130mm
no name headset (tantan installed it).  i think it is a zs44/zs56 size.  as the headset was already installed when i received it, i'm not sure of the max insertion depth
no name rear axle (from tantan)
wheels: EIEcarbon A29C30D28 rims, 28 bladed pillar spokes, brass nipples, 350 SP CL hubs, steel shimano freehub, 36t ratchet, light front tube, heavier rear tube, 2.35 racing ralphs (F+R)
stop: XT m8000 brakes, RT81 180mm CL rotors
go: m9000 xtr 11 speed shifter, XT8000 rear der, xt8000 11-42 cassette, KMC 11 speed chain, rotor rex 3.1 crank with absolute black 32t oval chainring, hope PF41 BB
cockpit: sunline V1 65mm stem, easton 711mm haven carbon bars, ODI lockon grips, cheapo QR seat post clamp, 3T doric limited seatpost (rigid, no setback), selle italia slr saddle

Yes this is a very XC, very XT build.

Next steps, prior to riding it:
- frame wrap the chainstay (i'll do the seat stay near the cassette as well, prob both sides)
- put some frame skin around the frame.  mainly the downtube, maybe the top tube, not sure where else yet.
- do a mini bleed of the brakes
- re-route the front brake hose.  fine tune the caliper position
- check if i can squeeze 22.2 hardware in the front shock mount, to confirm if the 21.85 i have installed is right.  if it fits, get the 22.2 RWS rollerbearing from my spare parts and install it on the rear mount (and use the solid 22.2 hardware on the front mount).
- check tensions in rear wheel spokes again (which werent that high even prior to putting the tyre on), perhaps put 1/4 to 1/2 a turn on all the spokes.

It is still raining outside. The trails would be quite muddy, for a few days too.  My prediction is that this weekend will merely be a fine-tuning ride around the streets near my house.

Bike has not been weighed, as my old feedback sports scale has stopped working.  I'm guessing 12.5kg.
I'll update this post with component weights (not all, but most) and, when i borrow my friend's scale, i'll put the total build weight on here too.

build notes:
- the chainring clearance on this frame is not that great.  You definitely need a chainline around 51mm or higher to fit a 32t oval (which is about the same max diameter as a round 34t).  i tried my old xtr crank (50mm chainline) with a round 34t NW chainring, and it was way too close (probably less than a mm between the chainstay and the wide teeth).  I gave up on that crank, and stole a rotor rex 3.1 crank off my XC bike, which has a 32t oval at a chainline just under 51mm (maybe 50.6?) and it is still close, but probably far enough (assuming there isn't too much flex in the frame and/or crank/chaninring.  i will keep an eye on it, for any marks on the chainstay.  i have fairly specific requirements for a crank (must have 24mm axle, must take a 32t oval ring, chainline around 51mm, q factor not too wide, needs to work with a variety of chains, 11 speed etc), and it looks like i'm gonna buy another rex 3.1 crank - quickly before they are all gone.  i was keen to try the new m9100 crank (maybe for my XC bike), but all the aftermarket chainrings seem to only be compatible with the m9100 12 speed chains.  So another old model rotor crank it is. The other good thing about those cranks is that you can adjust the chainline a few different ways, so if i have clearance issues, i can easily fix it.
- the 350 front hub seems cheap compared to the 240s hubs i am used to.  the loose end caps make it hard to install the wheel on the bike, and the rattling when they are off the bike. no big deal, but just noticeable for me.  i am considering looking into those torque caps. 

I have a few imminent purchases, such as a DHF 2.5WT front tyre, a longer air shaft for the fork (probably 140mm).  then, depending on how it rides, i might get some offset bushings (to drop the BB and slacken it), or maybe buy another shock (probably a mcleod) and short shock it.  trying to keep the spend down, but i will have to get another rotor crank (dont want to be swapping one crank between bikes) and seriously considering avoiding buying a new dropper post and instead steal the reverb off my other bike (but it is non-stealth, and 30.9 so will need a shim).
« Last Edit: August 30, 2019, 08:52:47 AM by sclyde2 »

scourge

Re: "XT" tantan FM08 29er build
« Reply #3 on: August 21, 2019, 08:16:38 PM »
Can't wait to see the final product and hear the review

supermoto65

Re: "XT" tantan FM08 29er build
« Reply #4 on: August 22, 2019, 08:32:05 AM »
Gloss looks nice!

Your experience mirrors mine, so far. I did add RWC kit on the shock mount, front and rear, and notice a tiny bit of play when lifting the bike off the ground ... just a tiny little "click". I think I need to adjust the spacers. I also agree, the shock bolt looks very cheap.

Looking forward to the final build!

ReverendRockRazor

Re: "XT" tantan FM08 29er build
« Reply #5 on: August 22, 2019, 09:47:52 AM »
 Ya I like the gloss. Feel like the matte just makes them look more generic.

sclyde2

Re: "XT" tantan FM08 29er build
« Reply #6 on: August 22, 2019, 04:23:14 PM »
Gloss looks nice!

Your experience mirrors mine, so far. I did add RWC kit on the shock mount, front and rear, and notice a tiny bit of play when lifting the bike off the ground ... just a tiny little "click". I think I need to adjust the spacers. I also agree, the shock bolt looks very cheap.

Looking forward to the final build!

Not sure why, but I've always preferred gloss over Matt.  I get gloss finish on all my chinese stuff (frames, rims, seatpost etc).

I had that tiny knocking issue on my FM058.  Yep, when lifting the bike off the ground by the saddle.  It was very minor, but it bothered me.  Not sure if it was an issue with my McLeod shock or the RWC hardware, but over time the roller bearings weren't tight any more.  I even bought a new RWC roller bearing kit which helped a bit, but it still wasn't quite right.  I also read that some other people had an internal knock on their McLeod shock at top out.  It seemed that I had either or both of these issues, but would have to send the shock away for it to be fixed - but couldn't be without the bike (had a few races on).  To make sure it was the shock (or hardware) that was the issue (causing the knock),  I eventually decided to just buy a new shock with standard manitou hardware.  Problem fixed.  I am yet to send my old shock to get fixed.  I really hope I don't have to go through this with my FM08.

sclyde2

Re: "XT" tantan FM08 29er build
« Reply #7 on: September 01, 2019, 02:36:23 AM »
New bike day has arrived, kind of.  The bike is in ride-able form, but the trails are too wet to ride.  I did a 20minute ride around the local streets, off a few curbs, a little bit of riding around the relatively dryer edges of a few parks, over a few rocks etc.

- i put some frame wrap on the stays (both drive side stays and the seat stay where the brake hose touches) and put some frameskin on the frame/fork (didn't do a very good job of it).
- i tried to squeeze 22.2 hardware into the front shock mount.  it wouldnt fit.  maybe 22.0 would fit?  the light carbon and yishunbike sites (which seem to have the same frame) seem to suggest "22" hardware. i put 21.85 back in and it seems pretty tight. 
- the fit is good, stretch to the bars with the 65mm stem seems about right, maybe only a tiny bit long.  it is looking like either a 50 or 60mm stem will be right.  geo otherwise seems fine too, seat tube not too steep, HA ok, about the right height.  perhaps the excessive rear sag helps this.
- i put about 120 psi in that low volume shock.  with this, it is at about 35% sag (maybe a touch more), which helps with the geo.  given the low volume, and i didnt hit anything too hard, it only used about 40mm of the 50mm of stroke, despite the low pressure.  we'll see how it goes on a proper ride, if i can get it to bottom, if i have to add air.
- i put 86psi in the fork (near the recommended) and it used only about 70mm travel.  dropped it to 80psi post test-ride.  see how it goes on a proper ride.  the remote lockout works well - not a total rigid lockout, just firms the fork up nicely for the stompy stuff.
- bike certainly doesn't accelerate like my XC bike.  it has been a while since i rode a >10kg bike i suppose.
- the first thing i noticed when i turned a pedal was that the seat-stays are wide - my calves brush them.  over the years i have heard people having this issue on various bikes, and i always figured that it must be because they have big calves.  i've never had this before.  while i got used to it and forgot about it within about 10 minutes of riding it, i am thinking i'll try to minimise this.  i am rethinking the idea to buy another rotor rex crank, which has a narrow q factor.  now thinking about putting some more XT on the bike, and get a M8000 crank, which has a q factor more than 10mm wider. cheaper than the rotor crank too. if i get the boost version, i should get a chainline around 52mm with an aftermarket oval ring (either AB or oneup).  i had a look at my old xtr trail pedals (which are destined for this bike) and they are pretty much the same spindle length as the xtr race pedals that are on it.

not many ride impressions at this stage, but it seems pretty solid, no noticeable rattles, other than a few cables rattling against each other.  weather should be good for next weekend, and i'll give it a good thrashing then.

after i sort out the crank situation, i have a feeling that the main priorities will be a dropper post and a grippier front tyre.  the suspension changes (longer air shaft for the fork and different rear shock, maybe offset bushings) will likely be lower priority - unless something adverse happens on the ride next weekend.

sclyde2

Re: "XT" tantan FM08 29er build
« Reply #8 on: September 08, 2019, 03:01:33 AM »
I accurately measured the bottom bracket height.  It is lower than expected, at 337mm.  See photos - i measured it multiple times, both sides etc.  This is with a 130mm travel pike, rear shock at about 199.5 eye 2 eye, 29x2.35 racing Ralph tyres.  This is difficult to reconcile to flyingdodo's 365mm BBH with a 170mm travel fork - by my calcs, the 40mm longer fork should only lift the front end 36mm, and the BB by around 14-15mm, but his bike is nearly 30mm higher at the BB.  Maybe it isn't an identical frame, or maybe flyingdodo's taller tyres make more of a difference than i expected.

As stated earlier, my (old) rear shock is low volume, which combined with the progressive frame, results in way too much ramp up.  So I am currently running the shock at low pressure (120psi) which gives around 40% sag.

A few short test rides at recommended pressure for the fork (85psi) had it using not much more than half travel, so I dropped it to 75psi (10 under recommended), which gives it around 25% sag (a bit more than ideal).

I went for a 2 hour trail ride today, with a lot of connecting pavement.  Pretty mellow trails, tyres barely left the ground.  Bit hungover, and carried a heavy backpack, lot of tools just in case.  Didn't feel that great today, so not a great 1st proper ride of a new bike.

Suspension at both ends felt very firm, like it wasn't using much travel.  Even with 40% sag, the rear shock didn't use more than 90% of the rear travel (45mm of 50mm stroke) and the fork barely used 95mm of the available 130mm.  Was overall a lot firmer ride than I expected.  My XC bike is plusher. Maybe the fork's bushings need breaking in, or maybe there's some air in the lowers (not sure if there's any merit in the rumour of a secondary air spring in those rockshox forks).

Bike seemed a little steep, definitely needs a longer fork.  Gonna go ahead and order the 140mm air shaft for the fork.  Gonna probably drop out a few volume spacers when I do this, so it more freely uses the travel, so I can run it with higher pressure less sag.  Running that much rear sag made the bike seem pretty low.  Probably wouldn't want it any lower - had a few pedal strikes.  I reckon I should be able to maintain the same BB height with a longer fork, combined with a shortened rear shock, running a higher pressure in a higher volume, so less sag.  Gonna stick to the earlier plan - get a 200x56 McLeod and shorten it around 3mm.  Will probably end up with around 140mm travel front and rear, with an unsagged BBH just under 340. A bigger 2.5" front tyre will slacken it and raise it a bit further.

The bike developed a creak during the maiden ride, when stomping on the pedals. Was pretty bad by the end of the ride.  Not sure if it is the bottom bracket or the suspension pivots/bolts.  Gonna wash it now, and take the cranks off (and put them back on my XC bike).  The new xt cranks should arrive next week, and I'll install those with my old xtr trail pedals.  Hopefully the creak is sorted with that swap.  If not, I'll have a look at the pivot bolts - might take them all out, grease the bearings, grease under the bolt heads, and loctite the threads. Should probably do all this anyway.

Was really missing a dropper post today, even though the trail wasn't that technical.  I have a 150mm oneup dropper post on the way too.

Bike is heavier than hoped - 12.65kg.  by the time I put heavier cranks pedals and dropper post on, it will go over 13kg, and then another ~200g more when I put a heavier front tyre on.  I could drop some weight going tubeless, but doubt it'll end up under 13kg.

The calves brushing the seatstays was less of an issue than expected. Still glad I ordered the wider q factor cranks, which will definitely lessen the issue, probably eliminate it.

In summary, not a great first ride, too hungover, and the suspension is far from sorted, such that I cannot really provide any decent feedback at this point in time. Overall, with the minimal effective suspension travel, the low BB and steep angles, the bike seemed to handle like an xc bike, but much more solid, heavier and less responsive to the pedal.  There was no noticeable Bob.  Bike really needs a McLeod - will order that soon.
« Last Edit: September 08, 2019, 03:05:43 AM by sclyde2 »

sclyde2

Re: "XT" tantan FM08 29er build
« Reply #9 on: September 11, 2019, 06:23:43 AM »
New xt cranks, oval chainring and dropper seatpost arrived today.  So did a bit of tinkering on the new bike.

First thing I did was pedal the bike around the backyard, to confirm that the creaking was still there after I washed it on Sunday.  Yep, pretty bad.  Sounded too bad to be the bottom bracket, so I had a look at the main pivot - loosened and pulled the bolt out.  It was totally dry in there, no grease on the bolt, seals, bearings, totally dry.  So put some grease in, on bearings, seals, on the bolt (incl under the head), but put some purple loctite (the weak stuff) on the bolt thread.  Put it back together, test rode it, creak gone.  Need to do the same with the rest of the pivots - maybe on the weekend.

Took the crank/pedals (the stuff borrowed from the xc bike) off, and put new XT crank (662g), new 32T oneup oval ring (54g) and old xtr trail pedals (372g) on.  Weight gain (over the XC bike's crank/pedals) is 199g.

Crank's spacing (both chainline and q factor) looks ideal.

The seatpost is yet to be installed.  Gotta do a bit of cable routing for it - could be tricky.  Post is 497g.  Haven't weighed the remote/cable.

After the dropper goes on, next upgrades will be a new rear shock, maxxis front tyre and longer air shaft for fork.
« Last Edit: September 11, 2019, 06:27:12 AM by sclyde2 »

GreyCactus

Re: "XT" tantan FM08 29er build
« Reply #10 on: September 14, 2019, 09:51:43 PM »
Great info! Can you ride the bike in rough and steep single tracks? Jumping and bottoming out the on rear? I’m waiting your report!!

For now, I’m waiting the arrival of the rockshox Pike ultimate and recently I bought a coil shock 8) cane creek IL coil. These one because I love coil feeling and I want the bike for long days on bike, shock is light and has climb switch, and also, water bottle compatible  ;)
« Last Edit: September 14, 2019, 10:02:39 PM by GreyCactus »

sclyde2

Re: "XT" tantan FM08 29er build
« Reply #11 on: September 16, 2019, 07:22:29 AM »
What a difference a week makes.

Since the previous weekend, I have made a few changes:
* Put on new crank, chain ring and old xtr trail pedals on (see above post)
* Unbolted all the pivots, greased the bearings, seals, under the bolt heads and put loctite on the bolt threads.  No more creak
* Installed a 150mm one-up V2 dropper.  Some advice: route the dropper post cable BEFORE installing the bottom bracket.  It was probably the trickiest bit of cable routing I've ever done.  Capgo noise protection was put over the cable inside the frame. When I installed the dropper remote, I had to move the fork's oneloc remote lockout - only place I could put it was above the bar on the right side - it looks a bit weird but works well, so I think I'll hold off on getting a twistloc to replace the fork remote.
* Removed 2 volume tokens from the fork.  When i had a look in it, I discovered that the fork had 3 tokens.  Now running only one token, with the same air pressure as last weekend, at 75psi, which is about 10psi under recommended
* Increased the air pressure in the rear shock.  Last week I was running only 120psi (~40% sag) in an attempt to use most of the travel on my old low volume shock.  I used about 90% of the travel with this setup last weekend, but the ride was overly firm.  I figured it was firm because was riding too far into the travel (where the spring rate ramps up), so I added 10psi this weekend, which reduced the sag to just on 30%, maybe 32%.

Went for a 2.5hr trail ride yesterday. Similar to last weekend's ride, but a bit longer.  A few observations:
* Fork used just under 120mm of the 130mm travel.  Gonna leave it there - at least until the longer air spring arrives.
* Rear shock used 90% of its travel, about the same as last time - however, i did go a bit harder this time, went over a few jumps etc.  Rear end seemed definitely more compliant with the higher pressure, less sag.  Gonna add another 5psi to see if that improves things further.  Bike is still not exactly plush - it definitely needs a more linear shock (i.e. higher volume).
* while not plush, the bike still floated extremely well through the rough stuff, holding more momentum than i think i've ever held through those familiar trails.
* with the short fork, the steering certainly is quick.  almost XC-bike quick, esp around the twisty stuff, the agility was surprising.  I think it could have something to do with 51mm offset in the fork.  Never ridden a fork with that offset before - my xc bike is the shorter ~44mm offset.  i was very much enjoying the initial turn in, setting up corners, the adjust-ability this bike has.  it just seemed much easier than i am used to, to get the bike entering turns exactly where/how i wanted to, such that late corner adjustments/corrections were rarely needed.  maybe the stiffness of the wheels/fork/frame were such that it wasn't upset by mid corner bumps, could hold the line better.  dunno.  but i like it.
* BB height is pretty much perfect.  Feels nice and low in the corners, hitting pedals a few times, but not too often.  gonna try to keep the bike at this height.
* Bike now weighs 13.18kg.  yeah, more than a pound heavier than i'd hoped.
* I've been in two minds about what fork length to go for.  140mm (+10mm) or 150mm (+20mm).  Definitely want it a bit slacker, but without upsetting the steering that i am enjoying.  Gonna try 140mm first up - have ordered the air shaft.
* I have also finally ordered the mcleod 200x56 shock, and high volume king can.  still aiming to run it at high volume, minimal rear sag (~25%).  we'll see what geo that gives it (slackness, ride height), and maybe look into lowering the rear end later.
* minion dhf 2.5 is on the way.  need more front end grip
* Seating position pretty good on the seatpost which has a little bit of set back. Slid the saddle right back.  with the old 65mm stem, the saddle-to-bars measurement is 10mm shorter than my XC bike.  undecided on stem length - gonna defer this decision until the geo is sorted out with the suspension changes.
* Wider q factor cranks reduced the calves rubbing on the seatstays, but it is still happening (just).  not a problem. 
* bike seemed to accelerate better this time.  COuldve been the high rear air pressure.  COuldve been my non-hangover this time.
* rear axle came loose.  started hearing a ting-ting-ting noise - the rear brake rotor was starting to contact the caliper.  tightened it up and it stayed tight for the 2nd hour of the ride.  will keep an eye on it
* my backside has become used to the $25 chinese carbon saddles i have put on my commuter bike and XC bike.  gonna get one for this bike too.

Great info! Can you ride the bike in rough and steep single tracks? Jumping and bottoming out the on rear? I’m waiting your report!!


yeah, have been ploughing through some relatively rough trails, but no big drops-to-flat etc.  went off a few jumps, but nothing major - probably big enough stuff to bottom my XC bike, but not this bike - never got beyond 90% rear travel on my 50mm stroke shock.  as mentioned above, that shock is low volume, and would take a massive hit for it to bottom on this progressive linkage frame.

GreyCactus

Re: "XT" tantan FM08 29er build
« Reply #12 on: October 02, 2019, 08:07:19 AM »
What a difference a week makes.

Since the previous weekend, I have made a few changes:
* Put on new crank, chain ring and old xtr trail pedals on (see above post)
* Unbolted all the pivots, greased the bearings, seals, under the bolt heads and put loctite on the bolt threads.  No more creak
* Installed a 150mm one-up V2 dropper.  Some advice: route the dropper post cable BEFORE installing the bottom bracket.  It was probably the trickiest bit of cable routing I've ever done.  Capgo noise protection was put over the cable inside the frame. When I installed the dropper remote, I had to move the fork's oneloc remote lockout - only place I could put it was above the bar on the right side - it looks a bit weird but works well, so I think I'll hold off on getting a twistloc to replace the fork remote.
* Removed 2 volume tokens from the fork.  When i had a look in it, I discovered that the fork had 3 tokens.  Now running only one token, with the same air pressure as last weekend, at 75psi, which is about 10psi under recommended
* Increased the air pressure in the rear shock.  Last week I was running only 120psi (~40% sag) in an attempt to use most of the travel on my old low volume shock.  I used about 90% of the travel with this setup last weekend, but the ride was overly firm.  I figured it was firm because was riding too far into the travel (where the spring rate ramps up), so I added 10psi this weekend, which reduced the sag to just on 30%, maybe 32%.

Went for a 2.5hr trail ride yesterday. Similar to last weekend's ride, but a bit longer.  A few observations:
* Fork used just under 120mm of the 130mm travel.  Gonna leave it there - at least until the longer air spring arrives.
* Rear shock used 90% of its travel, about the same as last time - however, i did go a bit harder this time, went over a few jumps etc.  Rear end seemed definitely more compliant with the higher pressure, less sag.  Gonna add another 5psi to see if that improves things further.  Bike is still not exactly plush - it definitely needs a more linear shock (i.e. higher volume).
* while not plush, the bike still floated extremely well through the rough stuff, holding more momentum than i think i've ever held through those familiar trails.
* with the short fork, the steering certainly is quick.  almost XC-bike quick, esp around the twisty stuff, the agility was surprising.  I think it could have something to do with 51mm offset in the fork.  Never ridden a fork with that offset before - my xc bike is the shorter ~44mm offset.  i was very much enjoying the initial turn in, setting up corners, the adjust-ability this bike has.  it just seemed much easier than i am used to, to get the bike entering turns exactly where/how i wanted to, such that late corner adjustments/corrections were rarely needed.  maybe the stiffness of the wheels/fork/frame were such that it wasn't upset by mid corner bumps, could hold the line better.  dunno.  but i like it.
* BB height is pretty much perfect.  Feels nice and low in the corners, hitting pedals a few times, but not too often.  gonna try to keep the bike at this height.
* Bike now weighs 13.18kg.  yeah, more than a pound heavier than i'd hoped.
* I've been in two minds about what fork length to go for.  140mm (+10mm) or 150mm (+20mm).  Definitely want it a bit slacker, but without upsetting the steering that i am enjoying.  Gonna try 140mm first up - have ordered the air shaft.
* I have also finally ordered the mcleod 200x56 shock, and high volume king can.  still aiming to run it at high volume, minimal rear sag (~25%).  we'll see what geo that gives it (slackness, ride height), and maybe look into lowering the rear end later.
* minion dhf 2.5 is on the way.  need more front end grip
* Seating position pretty good on the seatpost which has a little bit of set back. Slid the saddle right back.  with the old 65mm stem, the saddle-to-bars measurement is 10mm shorter than my XC bike.  undecided on stem length - gonna defer this decision until the geo is sorted out with the suspension changes.
* Wider q factor cranks reduced the calves rubbing on the seatstays, but it is still happening (just).  not a problem. 
* bike seemed to accelerate better this time.  COuldve been the high rear air pressure.  COuldve been my non-hangover this time.
* rear axle came loose.  started hearing a ting-ting-ting noise - the rear brake rotor was starting to contact the caliper.  tightened it up and it stayed tight for the 2nd hour of the ride.  will keep an eye on it
* my backside has become used to the $25 chinese carbon saddles i have put on my commuter bike and XC bike.  gonna get one for this bike too.

Great info! Can you ride the bike in rough and steep single tracks? Jumping and bottoming out the on rear? I’m waiting your report!!


yeah, have been ploughing through some relatively rough trails, but no big drops-to-flat etc.  went off a few jumps, but nothing major - probably big enough stuff to bottom my XC bike, but not this bike - never got beyond 90% rear travel on my 50mm stroke shock.  as mentioned above, that shock is low volume, and would take a massive hit for it to bottom on this progressive linkage frame.
Any news?
I’m waiting your updates!
My fork hasn’t arrived yet  :(

Cheers!

sclyde2

Re: "XT" tantan FM08 29er build
« Reply #13 on: October 02, 2019, 11:41:32 PM »
I haven't ridden the bike since the last post (weekend of 14/15 Sept).   The following weekend involved some marathon xc racing on my xc bike, and last weekend was a no-riding weekend, as I had family visiting.

Will get back onto the new bike this coming weekend, to test out the latest upgrades:.
- fork extended to 140mm with new air shaft.  I also took out the last volume token, to see how it goes with max volume.
- 200×56 McLeod rear shock.  Also got a king can for it, and have it set at max volume.  I aired it up with 140psi, which is more than I had in the other shock, but on this one it feels a lot pusher.  Will check sag before I ride it (Will start at 25%) and will probably need to increase pressure further.
- new front tyre - 2.5 minion dhf wt exo maxterra.  Heaviest tyre I've ever owned, at 1037g.  Still running tubes at the moment.
- changed the saddle (to the same Chinese saddle I have on my other bikes) and ditched the qr seat post clamp for a hope clamp.

Bottom bracket height is currently around 443mm, which as expected is higher than before (longer fork, taller front tyre), but is lower than where I thought it would be.  With a 56mm stroke shock, I am guessing it has 150mm rear travel presently. As mentioned earlier, I plan to get some spacers to reduce the rear shock 2.5mm (to 197.5×53.5), which will give it about 142mm rear travel with a BBH around 337mm which is probably about as low as I want to go.

We'll see how it goes as is this weekend first though.

sclyde2

Re: "XT" tantan FM08 29er build
« Reply #14 on: October 08, 2019, 01:07:32 AM »
The new bike still hasn't yet quite reached its 'final' state, so the upgrade-testride cycle continues.

The latest test ride went close to expectations.  Not a great ride, as the trails were still wet from rain from the days before, and not familiar with the new tyre etc.

Firstly, the longer fork and taller front tyre definitely made the bike feel noticeably taller.  I was surprised at the difference.  I think it was barely 6mm higher at the bottom bracket - though I did re-measure it, and it was closer to 445 than the earlier measurement of 443.  I didn't hit my cranks once, riding the same trails as the previous ride, including a lot techy climbing.  And I was noticeably worse at cornering too.  Perhaps the wet roots and rocks contributed though.  Not sure.  But this has confirmed my approach with this bike, to lower it below the frame's standard specced geo, with a 10mm shorter-than-spec fork and lowered rear end via a shortened shock.  I still plan to start with 2.5mm off the shock's stroke/length, which translates to a ~8mm lowered rear end (to about 142mm travel), but I could end up droping it further again.  My only reservation about going further is that the angles might be getting a bit slack - I don't think my trails or riding style would benefit from a HA much lower than 66.5.  I'm glad I went for a 140mm air shaft for my fork too, as a 150mm fork would've made the bike too tall (or too slack, if I dropped the rear end to bring it back down).

For the first time, I noticed the feeling of being a little further back, which will get worse when I lower the rear end.  However this was only on a super steep climb (Probably 15%grade), so I don't think it will be a problem.

I thought I put 75psi in the fork, but I think I was mistaken.  I might've put the recommended 85psi in, just in case it bottomed with the no volume tokens in it.  Got over halfway through the ride and noticed the fork barely used 110mm of the 140mm.  I dropped  it to 75psi for the rest of the ride, but didn't hit anything big, so it barely used any more travel. I'll leave it as is, and see how it goes on some bigger stuff.

With the rear shock on full volume, I went for low sag initially, and pre-ride settled on 160psi to get just under 25% sag.  Mid way through the ride, it had used only 44mm stroke (of 56mm, so about 80%), so I dropped it to 155psi.  Was still around 44mm at the end of the ride.  I'll drop it to 150psi after I shorten the shock.  As expected, the McLeod shock was awesome at erasing bumps, while at the same time not ever feeling wallowy.  I thought the not-high main pivot on this frame could result in a bit of Bob, but it is near non-existent.

With the wet trails, i was a bit hesitant to really put the new DHF tyre into any big leans, but in hindsight it barely slipped at all.  Perhaps the next (hopefully drier) ride will be better, and I have more trust in it.

The latest round of upgrades added more weight (mainly the tyre).  Bike is now 13.44kg, which is probably as heavy as it will ever get. It will lose a little weight when I go tubeless, and a slightly lighter stem.
« Last Edit: October 08, 2019, 01:14:34 AM by sclyde2 »