I purchased this bike used (and like it a lot). I’m looking at upgrading and need the size for the BB. Online I can see that in recent years the size is 42mm x 79mm. But the R5 isn’t a new “model”.
Does anyone know for sure whether or not the R5s of the last decade also use this size?
TIA
Yes, that bike has a BBright format which is offset 79mm
I recommend a thread together BB - lots of options here https://wheelsmfg.com/bottom-brackets/bbright.html
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I don’t know anything for sure but came here to say I feel your pain.
I recently replaced a BB on a 2018 Cervelo S5 and a 2013 Cervelo P5.
I *think *(please treat this as totally useless conjecture) that the S5 was a BBright with dimensions 46x79.
Happy BB search!
I can recommend wheels mfg BB press as a high quality tool though! (no affiliation)
If you need rapid response, Hambini happens to have excellent and professional customer service no matter what folks think about his youtube videos. He’ll point you straight to links for exactly what’s needed, if you decide to go with one of his one-piece BBs. This is not an endorsement for Hambini and I have no affiliation. He’s just fast on email, and helpful with specifics and answering questions for interested customers.
I *think *(please treat this as totally useless conjecture) that the S5 was a BBright with dimensions 46x79.
I’m hopeful, but really, what’s 4mm between friends? 
Just slap a little extra loctite in there and you’re good to go!
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Cervelo BB are a nightmare. Often Cervelo do not know as the BB differs depending on bike spec, for example some models a spacer was incorporated into a unique Rotor crankset, so the BB length was different. The R5CA has a different BB diameter to the R5 etc. It’s a bit of a minefield
Cervelo BB are a nightmare. Often Cervelo do not know as the BB differs depending on bike spec, for example some models a spacer was incorporated into a unique Rotor crankset, so the BB length was different. The R5CA has a different BB diameter to the R5 etc. It’s a bit of a minefield
You’re not given me a warm fuzzy. 😂
Is the only way to know for sure to get some calipers and measure it?
My bike does have “SL†on the front forks if that makes a difference.
The R5CA has a different BB diameter to the R5 etc. It’s a bit of a minefield
If you could afford the R5CA, you could afford to send your Bentley round to the bike merchant to fetch the mechanic to fix it.
Yes, that bike has a BBright format which is offset 79mm
I recommend a thread together BB - lots of options here https://wheelsmfg.com/...rackets/bbright.html
I second the comment, you absolutely want a threaded BBRight bottom bracket from Wheels Manufacturing. Just choose one with the appropriate bearings to handle your crankset, and as Ron Popeil of Ronco Rotisserie fame would say, “set it and forget it”
Okay, I’m learning a little as I go, and I’m a slow learner.
So, the BB is like the old rear axle of a truck without the pumpkin. There’s an exterior tube and an interior axle. The bearings on the ends of the axles have an outside diameter that must fit the exterior tube size and the inside diameter must fit the axle. With a BB the larger number (79mm) must be the diameter of the hole in the frame and the smaller number (42mm in my example) must fit the “axle†(I don’t know what it’s called) of the crank.
Is this correct?
If so, then I’m looking for a 79mm outside diameter BB with an inside diameter that fits whatever crank I’m getting. This could be 42mm, 46mm, or something else, or are all crank “axlesâ€/“shafts†the same diameter (hard for me to believe that).
Thanks for all the education.
You’re not given me a warm fuzzy. 😂
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It’s not as hard as he is making out.
The only way a Cervelo released after 2011 doesn’t have a pressfit 46/79 is if it’s an R5CA with direct fit 42/79
You don’t have one of those so there is no confusion
Mattsurf is referring to the variety of cranks that have been specced on the bikes, which is a different problem from the size of the shell in the frame
Post a pic of your bike if you want to be really, really sure
Okay, I’m learning a little as I go, and I’m a slow learner.
So, the BB is like the old rear axle of a truck without the pumpkin. There’s an exterior tube and an interior axle. The bearings on the ends of the axles have an outside diameter that must fit the exterior tube size and the inside diameter must fit the axle. With a BB the larger number (79mm) must be the diameter of the hole in the frame and the smaller number (42mm in my example) must fit the “axle†(I don’t know what it’s called) of the crank.
Is this correct?
If so, then I’m looking for a 79mm outside diameter BB with an inside diameter that fits whatever crank I’m getting. This could be 42mm, 46mm, or something else, or are all crank “axlesâ€/“shafts†the same diameter (hard for me to believe that).
Thanks for all the education.
No. The 79mm spec is a reference to the width of the bottom bracket/frame width at BB. The smaller number, which is 46mm for BBRight as Alex listed, is the frame shell I.D.
Contrary to others here I’m not a wheels mfr. BB fan because the guys that run the company refuse to support individual bike owners or questions about their products. Their answer for any inquiry is to take it to the shop. If you have a PF BB shell that’s out of spec the screw together feature won’t overcome a loose shell.
For PF BB’s the one piece BB is a great option. I recommend BBInfinite.
The other criterion here is what kind of crank you will be installing as this will set the diameter of the inside of the BB bearings.
Okay, I’m learning a little as I go, and I’m a slow learner.
So, the BB is like the old rear axle of a truck without the pumpkin. There’s an exterior tube and an interior axle. The bearings on the ends of the axles have an outside diameter that must fit the exterior tube size and the inside diameter must fit the axle. With a BB the larger number (79mm) must be the diameter of the hole in the frame and the smaller number (42mm in my example) must fit the “axle†(I don’t know what it’s called) of the crank.
Is this correct?
If so, then I’m looking for a 79mm outside diameter BB with an inside diameter that fits whatever crank I’m getting. This could be 42mm, 46mm, or something else, or are all crank “axlesâ€/“shafts†the same diameter (hard for me to believe that).
Thanks for all the education.
No. The 79mm spec is a reference to the width of the bottom bracket/frame width at BB. The smaller number, which is 46mm for BBRight as Alex listed, is the frame shell I.D.
Contrary to others here I’m not a wheels mfr. BB fan because the guys that run the company refuse to support individual bike owners or questions about their products. Their answer for any inquiry is to take it to the shop. If you have a PF BB shell that’s out of spec the screw together feature won’t overcome a loose shell.
For PF BB’s the one piece BB is a great option. I recommend BBInfinite.
The other criterion here is what kind of crank you will be installing as this will set the diameter of the inside of the BB bearings.
Our experiences with Wheels Mfg customer service are wildly divergent. I’ve had great interactions with them.
Okay, I’m learning a little as I go, and I’m a slow learner.
So, the BB is like the old rear axle of a truck without the pumpkin. There’s an exterior tube and an interior axle. The bearings on the ends of the axles have an outside diameter that must fit the exterior tube size and the inside diameter must fit the axle. With a BB the larger number (79mm) must be the diameter of the hole in the frame and the smaller number (42mm in my example) must fit the “axle†(I don’t know what it’s called) of the crank.
Is this correct?
If so, then I’m looking for a 79mm outside diameter BB with an inside diameter that fits whatever crank I’m getting. This could be 42mm, 46mm, or something else, or are all crank “axlesâ€/“shafts†the same diameter (hard for me to believe that).
Thanks for all the education.
No. The 79mm spec is a reference to the width of the bottom bracket/frame width at BB. The smaller number, which is 46mm for BBRight as Alex listed, is the frame shell I.D.
Contrary to others here I’m not a wheels mfr. BB fan because the guys that run the company refuse to support individual bike owners or questions about their products. Their answer for any inquiry is to take it to the shop. If you have a PF BB shell that’s out of spec the screw together feature won’t overcome a loose shell.
For PF BB’s the one piece BB is a great option. I recommend BBInfinite.
The other criterion here is what kind of crank you will be installing as this will set the diameter of the inside of the BB bearings.
Our experiences with Wheels Mfg customer service are wildly divergent. I’ve had great interactions with them.
That might change if you found yourself with a shell that didn’t match their BB spec. That is why I qualified my specific complaint. Their BB installed loose and screw together isn’t a fix for that. In the same shell Chris King and Kogel options both ended up fitting. To be fair all three BB’s mic’d out to different O.D.’s. But my contacts with them requesting guidance resulted in multiple rude, dismissive and unapologetic responses.
Thanks for the clarification. It definitely helps me,
I’m looking at upgrading to SRAM Force AXS etap wireless, with the non-power Force crank. I’m trying to make sure I either have the correct BB now or purchase the right one.
I have a couple of photos, but have to get them reduced in size to upload. Maybe I can get that done later this afternoon if anyone thinks they would help.
Those cranks should be interchangeable using your current BB
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Thanks for the clarification. It definitely helps me,
I’m looking at upgrading to SRAM Force AXS etap wireless, with the non-power Force crank. I’m trying to make sure I either have the correct BB now or purchase the right one.
I have a couple of photos, but have to get them reduced in size to upload. Maybe I can get that done later this afternoon if anyone thinks they would help.
Going with a SRAM AXS crank will generally mean you’ll be going with a DUB crank spindle so you’ll need a DUB-specific BB. These BB’s are basically just the 30mm BB30 standard with the crank spindle diameter reduced (28.99mm) to allow plastic bushings between the spindle and the bearing inner race. Having another standard is a PITA, but at least some of the complaints about creaking bottom brackets come from the metal to metal contact between spindles and bearings which this eliminates. This also may mitigate wear at this same interface as it is common to see used cranks with the spindle anodizing worn thru where is meets the bearing race(s).
SRAM does offer the GXP option (24/22mm spindle diameter) for some of their cranks. These will be harder to find and might require using GXP replacement crank arms to yield a full GXP crankset. DUB is going to be much more common so probably not worth going with their older standard.
I would guess your current BB is not DUB.