Carbonda fm936 Thoughts

[Medico]

My frame is set to be delivered Friday, and I have a Mara on the way as well... hopefully it all plays together nicely, I went with the mara because it runs lower than most other shocks and has a max psi of 400, necessary for a clyde like myself. I'll see how much room there is and maaaaaaaybe I can fit a king can on there to improve progressive qualities

Which size mara did you order? I can only find 165x40 or 45... There should be spacers to.make it 42.5...but where?

[Swolie74]

Which size mara did you order? I can only find 165x40 or 45... There should be spacers to.make it 42.5...but where?

I got the 45, I can make an HDPE spacer to bring the travel down as much as I need. Adding a custom spacer is much easier than trying to destructively remove the aluminum spacer inside the shock.

[Swolie74]

The silver aluminum spacer is what limits the stroke... like I said, I would rather add another spacer than try and cut that off/modify

[InsaneDawe]

Random Update:

I've been using my FM936 setup 165x42.5 rear with 130mm Pike up front and it has been a amazing. Not the fastest but it has been more than capable for a lot of the riding I do. My fork is a 51mm offset and it feels very twitchy with 760mm bars, I imagine 4Xmm offset would suit the bike much better. I setup my Deluxe RT3 shock,off a giant anthem, quite soft and it bottoms out on jumps sometimes but I think with some air tokens I can get it just right. I am 5'11" and bought a large and it does feel a bit long but it is a nice race position vs the short reach position a lot of other bikes I've tried.

I took my bike down to Brown County State Park in Indiana this weekend. Took it down Hobbs Hollow "Jump" trail and it didn't snap. I was probably jumping 1-3 ft in the air and still casing some of the jumps. Normal 2300g layup for reference. I have full confidence in the durability of my frame

[Swolie74]

My other question is fitment of the headset bearings,

https://imgur.com/a/PpyGDTy

That is as flush as I can get it, and is not a tight fitment at all i.e. will fall out under its own weight - not like any pressfit bearing I have used before!

I haven't seen it mentioned elsewhere but after several days of chasing down my frame (UPS has been a nightmare) I have this exact issue... I measured the cavity for the bearing and it is a hair over 42mm (42.038), while the bearing and headset sent is IS41 (41mm OD). I emailed them and was told that I was sent the CORRECT hardware and they designed the gap to be way oversized... also aside from that the surface finish in the frame taper where the bearing seats against is atrocious.... even if it was supposed to be a "loose" fit (never heard of a bearing fit with 1mm oversized clearance), that surface finish would in no way provide a solid/even locating surface to spread out a load...


On a lark I decided to look up the spec that NS uses, and they spec a IS41.8 (IS42)... which makes total sense. Do I bother arguing with them or just order the correct headset and move on. Not only that the cap which fits over the bearing doesn't seal against the frame and leaves an obvious gap.... There's no way that can be correct.

I measured the cover and it is 7.5mm thick, after doing some research Can Creek makes a headset with a cap 9mm thick.. which I believe should be adequate....

https://www.jensonusa.com/Cane-Creek-40-IS42-1-18-Headset

This is the first bike I've built so I'm not sure what is traditionally acceptable and what isn't... as a Machinist by trade I can easily machine the cavity to correct the taper and order the correct headset, but I didn't anticipate it requiring this much additional work. I'm almost more inclined to machine an insert and epoxy it in place.. It will increase my stack but give me an absolutely perfect surface for the bearing without potentially sacrificing some of the structural rigidity.

[Kk5551]

Hello all!  I am 6'2 with 34 inseam and can't decide between a L or XL FM936.  Any thoughts or feedback from those who have built theirs up?  Thanks!

[Lovewookie]

Hello all!  I am 6'2 with 34 inseam and can't decide between a L or XL FM936.  Any thoughts or feedback from those who have built theirs up?  Thanks!

go XL. I'm similar, albeit slightly shorter legs and went for a L. It just felt really short when seated and a compromise. yes, the seat tube on the XL is pretty big, but the fit will be better.

[Swolie74]

Hello all!  I am 6'2 with 34 inseam and can't decide between a L or XL FM936.  Any thoughts or feedback from those who have built theirs up?  Thanks!

Really depends on what you personally find the most comfortable. I'm about the same size and went for a L because it more closely matches the geo of my current bike that I intend to do all my training on....

What do you currently ride and how does it relate to this frame?

[AdamR28]

*snip*

20+ years in the bike industry and keen hobbyist general 'engineer' & DIY framebuilder here... I feel your pain. Some bike stuff is weird and just wouldn't be acceptable in the areas / tolerances you normally work in!

The frame is definitely for the larger 41.8mm size bearing, but it is not designed to be a press fit in my experience. The reaming tool I have measures a hair over 42mm, for example.

In short, I'd stick the 'correct' bearing in there (41., and ream the head tube so the bearing surface is nice and clean. That should do the trick. You can buy just one of these bearings separately if you need, and all the other hardware you've got already will work just fine.

The 'next level' would be to get a nice quality headset, something like the one you linked to, with a top plate that actually is the correct height and has a seal - however, don't be alarmed if you have to spend some time tinkering to make that happen, there really isn't much of a 'standard' for how much bearings stick up out of top headset cups!

[NathanJudge]

Shifting issues. Transmission or frame/hanger?

Had my FM936 built up for a few months now, 500miles and enjoyed it for the most part aside from one, rather major grumble.

Since day one I've not been able to get the gears shifting correctly.

Transmission is 12speed XT (cassette, mech, shifter, chain, optislick inner cable that I then upgraded to the polymer, SP41 outer cable).Yes, cable routed correctly. It's always a little out and as 12speed sprockets and chains are so narrow a little out is almost intolerable. It alters during the ride, i.e 1-2-3 good a start of ride but then not good by the end (even if an easy ride so haven't hit it on a rock, etc). It alters depending on the suspension setting (have a nude shock with 3 settings). It alters during suspension compression. It's never quite right.

I wonder if the clutch on the mech is partially to blame for a number of reasons. Firstly, I know the clutch affects shifting, increasing friction at the shifter and think it alters, ever so slightly where the mech rests after a shift, which if true means that because of suspension movement and chain growth the clutch is constantly 'working' and so minutely affecting where the mech sits and given how minute adjustments affect shifting it must be having an impact.

But also wonder if the clutch is actually causing the hanger to bend - as I say when the suspension is compressing causing chain growth it's effectively pulling at the clutch, and so mech, and so mech hanger all the time - it must be having an impact - which is kind of confirmed that when I check the hanger alignment with the tool it's always ever so slight out - is it plausible? Maybe the hangers on these fm936 are a little soft?

I've serviced the clutch, and backed off the tension as much as I dare and it is better but I just dont like the fact I feel like I'm having to compromise on a nice bike!

Like the idea of 1x12 but just seems to sensitive or is it the hanger/frame? - bring back 2 x 10 I say 

Any thoughts appreciated.

[Medico]

Moet likely your hanger is bend. And no way it's because of your 1x drivetrain.
Other thing I had: you have to check how you did the cable at your derrailer!

No way I will ever go back to 2x or 3x drivetrain...like going back to horse and wagon.

[PrincessZeeeeta]

when I check the hanger alignment with the tool it's always ever so slight out - is it plausible?

I would say definitely yes.

Maybe the hangers on these fm936 are a little soft?

Actually it's normal. Changed already two after hits by rocks. I have some cusom milled hangers and it's way more stiffer but I would like to bend another hanger instead of mech:)

Transmission is 12speed XT (cassette, mech, shifter, chain, optislick inner cable that I then upgraded to the polymer, SP41 outer cable).

Does it requires different hanger like on some other frames?

I finally killed my gx derailer and wanna try new shimano stuff. I read shimano 12 speed shifter/mech should work with 11 speed cassettes with no problems.

[PrincessZeeeeta]

Meet another one red carbonda

Oh, I think I can share some experience and write some review already. May be it helps to someone.
Rode ~120 hours, ~1700km, through winter, week in mountains, ~10 xco/xcm races.

So I must say it's the most chill an forgiving bike that I have. It doesn't feel like a typical xc bike when you move yourself around all the time on tech sections and may be sometimes trying to survive. It's something like "hey boi relax and stay on pedals, I do the rest". And here is the caveat - now I ride tech section with greater speed and confidence so mistakes became "more expensive". Overall it's an xc bike that feels like older enduro in my opinion and I love it.

Little notes about setup and hardware:
1. 120mm on the front - just great. Feels like infinite amount of suspension. Actually I can't imagine this frame with 100mm on the front. Bb is quite low on my taste.
2. No remote locks. I decided to not take part in races this season so no need to lockouts I thought. But this season already the most race filled season I ever had  . And you know what? It turns out that remote lockouts not so required as I thought before.
3. 720 bar switched to 760 riser with 45mm stem. Just +100 to handling and confidence on descents with a little penalty on narrow sections. +10mm headset spacer for even better feeling, but it's no go for xc races for me.
4. SDG Tellis dropper - just piece of shite. Those cheaper brandx/tranzx much better.
5. Changed already 3 lower bearings on headset. It's just starting creacking and it becomes worse. I should try to trim fork crown may be.
6. Tried to run "dropperless" but it's sooooooo uncomfortable. Saddle being not in that position like on my previous xc bikes so it limits butt movements more than ever. Not a problem on learned race courses but I'm too lazy to swap seatposts.

[Zomb1e]

4. SDG Tellis dropper - just piece of shite. Those cheaper brandx/tranzx much better.

Nice review, thanks!
Tell please a lil bit more about your experience with sdg dropper. A was always thinking that it is nearly the same beast as tranz x/brand x (which are also crap imho).

[PrincessZeeeeta]

Tell please a lil bit more about your experience with sdg dropper. A was always thinking that it is nearly the same beast as tranz x/brand x (which are also crap imho).

So I had both tranz x and brand x and it's not the best thing but for that price it's acceptable. When I assembled carbonda I decided to try something better and somehow sdg tellis was the amazing dropper by magazine and user reviews. Ok, take my money. It turns out that for the double priced brand x you get a brand x but with huge play from the box, absolute crappy bushings and seal that doesn't work. Seal by itself may be not bad at all but sdg did a genious move - they made a moving part (shaft?) not slick like stanchions of your fork for example but ribbed. See the problem? Tons of dust below seal especialy in wet conditions. On the last race it's just stuck (was a lot of water) with full of dirt under the seal. Never had any problems with cheaper droppers. Now I can't decide what to try next: trusted brand x or something else.

Also much appreciate theirs 120 hours service video, lol. "Just rub stanchion, put some grease inside and go for a ride". No way it works:)