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Messages - Schoobang

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1
29er / Re: Carbonda fm936 Thoughts
« on: May 21, 2020, 02:07:00 PM »
Quote from: Pharaohollie on May 20, 2020, 05:48:01 AM
@Schoobang: Very nice build! Love that stem and now I want one :)

I think the 1.3kg difference in weight between our builds is mostly in the fork (yours is approx 600 lighter!) and tires. I dare not run those Schwalbes where I ride, though! I think I might rip them on the first ride out :)

What do you weigh and what pressure are you running in your shock?

The stem is really nice. Weights exactly as spec says. I was a bit worried it might flex too much but it seems solid enough for this kind of bike.

I weigh about 79kg and I run the shock at 220 psi if I remember correctly.

2
29er / Re: Carbonda fm936 Thoughts
« on: May 21, 2020, 06:13:48 AM »
Quote from: theirishrider on May 21, 2020, 05:41:43 AM
@Schoobang looks great! You'll have to give us a side shot  ;D


3
29er / Re: Carbonda fm936 Thoughts
« on: May 19, 2020, 05:45:27 AM »
My FM936 standard XL ended up at 11.4 kg with pedals and bottle cage which I am very satisfied with. With a pair of nice carbon wheels, carbon cranks and a new cassette it could be possible to get closer to 10.5 Kg. Especially if I loose the dropper (but why would I wanna do that?  :)).

Full Spec:
Carbonda fm936 Standard XL
Rockshox 29" SID Ultimate 120 mm blue 2021
2018 FOX Perf 165 x 42.5 DPS Float

Race face next 760mm
77Designz stem 1 45mm
Cane Creek slamset
MAGURA MT Trail Sport with Storm SL.2 180/160mm
ESI GRIPS Soft Grip Chunky

Rear deraileur XT 11-spd Rear RD-M8000
Trigger SHIMANO XT SL-M8000 I-Spec II for 11
Casette SRAM GX | 11-speed XG-1150 | 10-42
SRAM PC X1 Bicycle Chain 11
SRAM GX Eagle DUB Crank 1x12  BOOST

Hunt trail wide wheels, 30mm inner
Schwalbe racing ray/ralph evo
Tubeless

Seat Specilized phenom pro elasto 155mm
OneUp V2 Dropper 150mm + OneUp remote
KCNC MTB SC11 Seat Clamp

Shimano Pedal, PD-M540


Some thoughts:

Took the first 40+km ride this weekend and everything seems to hold up well. Bike is fast and agile. Climbs very well. I am used to ride a 140/140mm trail bike though... The bike is quite long but I only noticed that on a couple of really tight/narrow/slow passages. BB is low as mentioned in other posts but for me that is not an issue, you just have to be aware and adapt. Also it is nice with a low center of mass.

I got cranks with a boost chain ring on now, but the chain line looks a bit off so I may try a non-boost chain ring.

I had two issues building the bike. The first one was that I couldn´t fit my 180mm dropper beacuse of a manufacturing error. Carbonda compensated me for that and I switched to a 150mm instead which should be enough. Saved 50 grams too =). The other issue was that the linkage was mounted completely dry, but it seems fine after a full do-over.

4
29er / Re: Carbonda fm936 Thoughts
« on: May 07, 2020, 05:58:02 AM »
Quote from: Opadeira on May 07, 2020, 05:47:13 AM
what type of derailleur hanger does the frame use? Is one that's easy to replace through online bike shops or should I order spare ones from Carbonda?

Not sure if you can get them from anywhere else. I asked carbonda to sent two extra hangers with the frame. I believe they charged a few dollars for them. A low price for one less thing to worry about.

5
29er / Re: Carbonda fm936 Thoughts
« on: May 07, 2020, 03:40:32 AM »
Quote from: Zdrenka89 on May 07, 2020, 02:25:59 AM
Nice build wfl3!

I am trying to figure out if i should get 175 or 170mm cranks. What do you guys suggest? (Im 191cm or 6' 3")
Is the BB to low for longer cranks?

I went with 175mm cranks since I am also a tall guy. On my test rides I noticed that the bb was quite low, but not annoyingly low. I f you run a 100mm fork you might want to consider 170mm cranks however. The bb height differ 7-8mm depending on if you use a 100mm or a 120mm fork. The SID 120mm 2021 that I use is actually 5mm longer that last years 120mm model so that also helped with my decision.

6
29er / Re: Carbonda fm936 Thoughts
« on: May 06, 2020, 04:44:18 PM »
Quote from: wfl3

Almost done.  Just gotta get the cockpit adjustments finalized and cut the steerer down to final length.

Impressive weight! What’s the key? Drivetrain is probably a few hundred grams lighter than mine but where did you shave of the other 1,5kg? Super light wheels filled with helium?

7
29er / Re: Carbonda fm936 Thoughts
« on: May 05, 2020, 10:30:48 AM »
Good news. Half a liter of grease later and the linkage is finally silent. So is the bb! I did however just go back and forth a couple of times on the street outside my house so we’ll see if it stays silent.

Also found out that I can’t tighten the upper pivot bolt with suggested torque if I want smooth movement. Hopefully it will work anyway with some blue loctite.

8
29er / Re: Carbonda fm936 Thoughts
« on: May 05, 2020, 08:31:03 AM »
Quote from: Pharaohollie on May 05, 2020, 07:13:26 AM
With 22.2mm hardware I have a small amount of play in the upper shock mount. The hardware I have seems to spec measured with cheapo calipers. I am using a spacer, for now, to take up the play, but will order a different set of 3-piece hardware to try.

I have no play at all there, I even have to use some force to get the shock/bushing in position. In the lower mount I had to use some shims to remove play.

9
29er / Re: Carbonda fm936 Thoughts
« on: May 04, 2020, 01:45:46 PM »
Quote from: theirishrider on May 04, 2020, 07:27:07 AM
Quote from: Schoobang on May 04, 2020, 06:14:48 AM
The hunt for what causes the creaking goes on. I thought the linkage was fine since I couldn’t get any creaking sound from compressing it, but when rocking it sideways it creaks, and I believe pedaling creates the same kind of force. Therefore I dismounted the linkage and noticed that the upper pivot bolt shows a lot of wear after just 5km of riding. Not just visual wear but I can actually feel it. Shouldn’t all movement be handled by the bearings? I asked carbonda and they replied that I should just reinstall everything with some oil. I am not 100% convinced but I will give it a try.
I think this could be caused by the bolt being undersized compared to the Internal Diameter of the bearing. Oil would help, but then its going to act as a bushing if the bearing isn't rotating correctly. Maybe some grease would be better- would stay in place better than oil. check the bearings arn't feeling 'gritty' which would suggest premature wear.

It didn’t make any difference. Bearings seems fine and I used grease. Everything was installed more or less dry before. Now I am doing the bottom pivot bolt, and it looks the same. Worn down on the non-drive side and everything is dry. They must have used a lot of force to get the bolt in place the first time. It took forever to get out. To be continued...

TLDR - dismount and check linkage before riding!

10
29er / Re: Carbonda fm936 Thoughts
« on: May 04, 2020, 06:14:48 AM »
The hunt for what causes the creaking goes on. I thought the linkage was fine since I couldn’t get any creaking sound from compressing it, but when rocking it sideways it creaks, and I believe pedaling creates the same kind of force. Therefore I dismounted the linkage and noticed that the upper pivot bolt shows a lot of wear after just 5km of riding. Not just visual wear but I can actually feel it. Shouldn’t all movement be handled by the bearings? I asked carbonda and they replied that I should just reinstall everything with some oil. I am not 100% convinced but I will give it a try.

11
29er / Re: Carbonda fm936 Thoughts
« on: April 28, 2020, 08:22:49 AM »
Quote from: theirishrider on April 27, 2020, 03:03:33 PM
Quote from: Schoobang on April 27, 2020, 11:36:54 AM
Problem is that this kind of bb doesn’t exist for my dub cranks, or at least I can’t find it. So I would need to buy new cranks as well.

Really wish I knew you could get it threaded from factory before...

sorry I dont want to beat a dead horse but I think C-bear stock them :) https://www.c-bear.com/en/products/sram-dub

Sorry but I may be missing something here. How is this different from the SRAM one I have installed now? They look very similar and neither is “thread-together”?

12
29er / Re: Carbonda fm936 Thoughts
« on: April 27, 2020, 11:36:54 AM »
Quote from: theirishrider on April 27, 2020, 08:50:15 AM
Quote from: Schoobang on April 26, 2020, 01:33:24 PM
Yeah, makes sense.

Creaking is still there even if I stand up pedaling or when I don’t hold the handlebar (not at the same time!). I was also suspecting linkage but I can’t force creaking without putting pressure on the cranks.

I expect that it's the bb creaking. check hambini's videos for more details about why BBs creak. basically its oval bb's where the bearings go in. The engineering reasons why they creak can be a few different ones but they can be mostly solved with a one-piece bb.

https://www.hambini.com/product/bb92-to-shimano-mtb-black-bottom-bracket/

Scroll down the page to the FAQs :)
essentially, the screw together provides a circular fit for the bearing and distributes the force more uniformly.  I'm an engineer but I've not actually seen a bb92 or this one piece bb in person ever.

something like this might be cheaper than a hambini:

https://wheelsmfg.com/bb86-92-outboard-angular-contact-bb-for-24mm-shimano-cranks-black.html
https://www.bikeinn.com/bike/wheels-manufacturing-press-fit-bb86-92-shimano-24-mm-bottom-bracket/137541473/p
https://www.bikeinn.com/bike/wheels-manufacturing-press-fit-bb86-92-shimano-24-mm-bottom-bracket/137541473/p
https://www.c-bear.com/en/products/bottom-bracket/pressfit-86-92-shimano-fsa-race-face-rotor

You can see here how the cup holds the bearings now rather than the frame.
https://wheelsmfg.com/bb86-92-tech

Hope that helps?

Problem is that this kind of bb doesn’t exist for my dub cranks, or at least I can’t find it. So I would need to buy new cranks as well.

Really wish I knew you could get it threaded from factory before...

13
29er / Re: Carbonda fm936 Thoughts
« on: April 26, 2020, 01:33:24 PM »
Quote from: brex on April 26, 2020, 12:24:36 PM
Grease only with a press fit bottom bracket. Any locker of any kind will cause headaches down the road. Guaranteed.
I'd bet the creaking is coming from the stem, handlebar or seatpost

Yeah, makes sense.

Creaking is still there even if I stand up pedaling or when I don’t hold the handlebar (not at the same time!). I was also suspecting linkage but I can’t force creaking without putting pressure on the cranks.

14
29er / Re: Carbonda fm936 Thoughts
« on: April 26, 2020, 01:06:48 AM »
Quote from: ChinaCruz on April 25, 2020, 07:08:03 PM
Quote from: Schoobang on April 25, 2020, 02:48:34 PM
How did you guys mount your bottom brackets? I mounted a SRAM dub one with grease according to Wings recommendations, but it creaks a lot when pushing hard on the pedals. Or is it something else that could make the sounds according to your experience? It started after about 15kms of riding.

For BB92, I get the thread-together bb from ztto or wheels manuf. I clean thoroughly and mount with Loctite 648. Then I press in NTN double sealed bearings with Loctite 648. Allow to cure 24 hours. Coat the outside of the bearing seals with a silicone based grease, use Chevron Ultra duty EP grease on the crank shaft, and install.

The threaded-together bb sounds like a great tip, however I have a dub crank and can’t find that kind of bb for that standard. Only for gpx and shimano.

I may try thread locker like loctitite otherwise which works well on my other carbon frame. But I am not sure I can remove those bearings without damaging the frame easily...

15
29er / Re: Carbonda fm936 Thoughts
« on: April 25, 2020, 02:48:34 PM »
How did you guys mount your bottom brackets? I mounted a SRAM dub one with grease according to Wings recommendations, but it creaks a lot when pushing hard on the pedals. Or is it something else that could make the sounds according to your experience? It started after about 15kms of riding.

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