Show Posts
1
29er / "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.
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.