ryanw what do You think about c-bear bottom bracket: "Sram DUB : Pressfit BB86" is it normal size of bearings?ryanw wrote: ↑Tue May 04, 2021 9:53 amStop reading up on crap that people say about X... Most of these plonkers look at something and make a call based on their 'experience' (read this as they make a judgment call based on sweet FA actual real-world practice using the product).
Hambini (Sanjeev) states he is not a cyclist but an engineer. On paper maybe it isn’t as good as a bigger 6806 type bearing, but doesn’t mean it’s rubbish.
I am a cyclist and the people I build bikes for are pretty handy on two wheels too.
Three C-Bear PF4130/DUB units that spring to mind that I've installed have been faultless on bikes with riders who have 360-450w FTPs, 70-90kg body weight, 1,500w+ peak power. They have not been treated kindly yet still running smooth as silk after probably 30,000 combined KM.
Now if you're a stronger rider than the above and exceed their numbers, I can't comment on how it will last, but I doubt you are, so stop worrying and don't constrain yourself to a 24mm crank...
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I have one in now that's having a service after being installed in July last year. Had a hard life but still perfect. This is owned by a 90kg / 400w FTP rider so definitely been through the ringer.
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Photo doesn't show inside of the holders or races ... so it's not really illustrating anything. Regardless of weight or power, and potentially partly because of the tiny bearing size, if it's done significant distance, both are almost certainly worn given that the bearings are ceramic coated.
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Three C-Bear PF4130/DUB - i think on photo is this.ryanw wrote: ↑Tue May 04, 2021 9:53 amThree C-Bear PF4130/DUB units that spring to mind that I've installed have been faultless on bikes with riders who have 360-450w FTPs, 70-90kg body weight, 1,500w+ peak power. They have not been treated kindly yet still running smooth as silk after probably 30,000 combined KM.
"Sram DUB : Pressfit BB86" - what do You think about that bb for PF86, what kind of bearings here ?
Thanks.
They're the same, just the DUB model uses a shim / cover reducer.
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RDY wrote: ↑Mon May 03, 2021 3:08 pm
His critique of GXP is valid though. Its variability of tolerances and the axle / bearing / crank interface is crap.
Cranks themselves are excellent and good value for money - and a textbook illustration of why Shimano should also move to thermoplastic cranks (they're cheap, easy to mass produce & don't fall apart). But if DUB fits your bike, you'd be mad to go with GXP now ... it isn't perfect, but it's a whole lot less *f##k* than GXP.
IMO the weakest link is end-user installation. GXP makes installation basically fool proof...you tighten a bolt until you physically can't and then there's zero play in the system. With pinch-bolt designs like Hollowtech II, it's a multi-step process with more opportunities for end-user error. The same goes for single-bolt designs + preload adjusters. If the person installing the cranks leaves any amount of play in the system, then that potentially causes abrasion to the spindle and almost certainly reduces bearing life.
All of this is way more likely to occur than GXP crank spindles being made outside of tolerance, no matter what Hambini says.
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Ask C-bear about "bearing size" and get answer:
"It is a custom bearing for C-bear BB86 sram dub.
Not double row."
C-bear not name actual size of bearing.
Ryanw sayed that bearings is durable.
Definitely go with C-bear custom bearing if it's "same size" as bbinfinite custom bearing (30mm ID, 40mm OD).
Which size C-bear bearing in "BB86 sram dub" ?
Thanks
Last edited by Thejingerr on Mon May 10, 2021 5:55 am, edited 1 time in total.
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ryanw : They're the same, just the DUB model uses a shim / cover reducer.Thejingerr wrote: ↑Sun May 09, 2021 4:16 pmAsk C-bear about "bearing size" and get answer:
"It is a custom bearing for C-bear BB86 sram dub.
Not double row."
C-bear not name actual size of bearing.
Ryanw sayed that bearings is durable.
Definitely go with C-bear custom bearing if it's "same size" as bbinfinite custom bearing (30mm ID, 40mm OD).
Which size C-bear bearing in "BB86 sram dub" ?
Thanks
So gxp and dub version have same durability ? Thanks
GXP and DUB are completely different brackets, yet both shall have great durability if installed and maintained correctly.
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Who says my customers aren't pro riders?...
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OT but that is 4.5 W/Kg, which is very good but nowhere near pro.
400 @ 72 = 5.55w/kg. Not shabby.
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