Xmcarbonspeed CS-R01 build

[mark335]

My local bike shop. Genuine SRAM DUB T47. Being said I had one of the bearings give out after 700 kms which is hardly better than a KACTUS one I bought for my other bike. My solution was to replace the bearings only - Going on 1000 km now.

 FWIW the KACTUS one was near $50 and the SRAM one was $75 CDN

 The bearings for the KACTUS BB were $10 each locally and the bearings for the SRAM BB (MR3040H7-2RS) from Ali were near $20 for 4 - local shop would have to order them AND they were more $$ than Ali.

Very quickly this bearing blew out, 700km is not much.
I'm intrigued by this topic because I also have a T47 86mm in my frame (bxt) and installed bb Token. I have the same thing, the first bearings lasted 2000km then started to squeak, the second Token bb 1000km and the same symptom. The strange thing is that they don't have a rolling problem, they just squeak. Now I ordered bb Kactus, which has a flange on the bearing - that is, there is no metal-to-metal contact between the bearing and the crank axle. I wonder if this will solve the problem and what the reason is:
- friction between the metal-to-metal contact
- misaligned bb t47
- poor quality bearings

[Daviddavieboy]

Very quickly this bearing blew out, 700km is not much. . .
- friction between the metal-to-metal contact
- misaligned bb t47
- poor quality bearings

 Both of the BBs developed a creak/click at the same point in their revolution. Upon removal and cleaning I was able to wash out 'dirt ?'  that was found between the balls and race. On the KACTUS I assumed it was ceramic particles and even with no load and clean a definite rough spot could be felt in the rotation even when spinning unloaded. On the SRAM bearings the particles may have actually been dirt ingress but again when rotating the bearing unloaded a rough spot could be felt. To note, this was only on the non drive side of the SRAM BB. When installing the new bearings I SOMTHERED the seals with grease to help prevent anything getting past them. Both of the BBs I bought use plastic sleeves to protect the crank.

 Fingers crossed, they both have been perfect - near 1000km on the SRAM and 500km on the KACTUS BB in my gravel bike. I assume my BB is aligned as the crank doesnt bind at all.

[Icyseanfitz]

I'm using this:

SENICX T47 68mm Ceramic Bottom Bracket Suitable for Shimano/SRAM GXP Road Bike Crank 24mm Shaft Gravel Bicycle Central Movement
https://a.aliexpress.com/_mPAkXeP

1100km on it, perfect still, I don't ride much in the rain though

[Daviddavieboy]

I'm using this:

SENICX T47 68mm Ceramic Bottom Bracket Suitable for Shimano/SRAM GXP Road Bike Crank 24mm Shaft Gravel Bicycle Central Movement
https://a.aliexpress.com/_mPAkXeP

1100km on it, perfect still, I don't ride much in the rain though

 To be honest I think the problem is with cheap bearings in the DUB format. They are SO SMALL that they plainly do not last. Between this and me being extremely fussy about noises makes for a bad combination. If I had to choose over again I would NOT use cranks with DUB axle sizing - I have (Shimano/Campagnolo) bikes with literally 10,000 kms and more on the same BB.

[Serge_K]

To be honest I think the problem is with cheap bearings in the DUB format. They are SO SMALL that they plainly do not last. Between this and me being extremely fussy about noises makes for a bad combination. If I had to choose over again I would NOT use cranks with DUB axle sizing - I have (Shimano/Campagnolo) bikes with literally 10,000 kms and more on the same BB.

I'm lost. Are you saying that T47 + 29mm/DUB axle = small bearings?
Because i know that PF BB86 / BSA + 29mm axle = bad, but i thought pretty much the reason why T47 exists is to accommodate 29mm axles with adequate sized bearings?

[Daviddavieboy]

I'm lost. Are you saying that T47 + 29mm/DUB axle = small bearings?
Because i know that PF BB86 / BSA + 29mm axle = bad, but i thought pretty much the reason why T47 exists is to accommodate 29mm axles with adequate sized bearings?

 Yes they are tiny. Have you never disassembled one ? TBH I am surprised that roller or cone bearings are not used as to give a larger contact area but that would be more expensive.

[bremerradkurier]

Yes they are tiny. Have you never disassembled one ? TBH I am surprised that roller or cone bearings are not used as to give a larger contact area but that would be more expensive.

They used to be a thing in the 1980s.

https://www.lucio-bici.com/shop/p/rare-nos-vintage-1980s-galli-super-criterium-titanium-italian-bottom-bracket

[Serge_K]

Yes they are tiny. Have you never disassembled one ?

Well then that's retarded! Why does DUB exist? Why does T47 exist? If neither allows for properly sized bearings?
All the bikes i built were using 24mm axles.

[Daviddavieboy]

Well then that's retarded! Why does DUB exist? Why does T47 exist? If neither allows for properly sized bearings?
All the bikes i built were using 24mm axles.

 I have several bikes and the two DUB/T47 bikes are the only ones I have had issues with. I did have a creakingdale SuperSix with a BB30 but that was the Bb style not the bearings. The solution was a praxis thread together BB. I no longer have that bike tho.


 I do have to say though since I put quality bearings in both (and sealed they with extra grease ) I no longer have any issues.

[dominikjablonski]

I wrote the wrong bike, not the wrong frame. He's on bad tyres (french sponsor), butyl tyres, large bars, wheels that aren't deep enough, and yes, a slow frame, that's not made for the flat, which means he loves his position out of the saddle climbing, but he's not comfortable in tuck, and so he catches more wind than he should.
And so, ride for 90min at 40kmh on the flat, add all of these "marginal" things together all at once, and it hurts. Idk how slow that frame tested on the tour magazine, but it can't have tested well.

That said, maybe i'm lying. Maybe i dont exist. Maybe i'm a russian bot. Maybe i'm a trad wife. Maybe sometimes i wish i were a trad wife.

Im also considering CS-R06 instead of CS-R01.

Could You post some drivetrain side photo of finished build?

[Daviddavieboy]

Im also considering CS-R06 instead of CS-R01.

Could You post some drivetrain side photo of finished build?

 Why one over the other ? just curious .

[Gloopann]

Why one over the other ? just curious .

Not OP, but I am also leaning more towards the R06 than the R01 for two main reasons: racier geometry and I think it looks betters.

[dominikjablonski]

Not OP, but I am also leaning more towards the R06 than the R01 for two main reasons: racier geometry and I think it looks betters.

+1

I agree 100% with that.

[Rebel_Yell]

Not OP, but I am also leaning more towards the R06 than the R01 for two main reasons: racier geometry and I think it looks betters.

The stack and reach seem to be same from what I see.  What am I missing?

[Da11as]

Well then that's retarded! Why does DUB exist? Why does T47 exist? If neither allows for properly sized bearings?
All the bikes i built were using 24mm axles.

One should look at how it is constructed and look for good aftermarket solutions. From what I know Sram use same tiny bearings regardless of BB shell to cut the costs, whether is T47->Dub or BB86->Dub. I got the issue when I bought shitty BB86->30mm axle BB which abruptly fall apart and destroyed the axle of my cranks. Then I bought Hope BB which is of another construction, has slightly larger bearings and lasted far longer. Yet again, it failed miserably and abruptly during the wet race and destroyed another crankset again

Moral of the story: big balls in BB = good, small balls in BB = bad.