Traditional threaded bottom bracket shells have a width of 68 mm, with the bearings supported outboard by the BB cups. Normally, for press fit bottom brackets, the width is wider than threaded type, as the bearings are already included inside the BB shell width. For a comprehensive guide to the various BB specifications, check out this link.
For Cervelo BBright, it is odd because it is a hybrid specification. It is a press fit type, but the drive side is not shifted outwards. Only the non-drive side is shifted outwards by 11 mm, giving a total BB shell width of 79 mm (68 + 11). This supposedly allows sufficient crank and chain ring clearance on the drive side, while allowing the non-drive side frame to be made wider for better frame stiffness.
This idea in itself sounds OK, but it creates an asymmetrical frame and bottom bracket. This is not a problem, but I have heard and read about many bad experiences with BBright bottom brackets, as they creak and squeak quite frequently. This can happen to any press fit bottom bracket design, if the frame and bottom bracket tolerances are not controlled tightly.
One of the best solutions is to use a set of press fit bottom brackets that thread the left and right side together, to prevent looseness and play that will cause creaking. That is why I had to get a threaded BBright bottom bracket that is heavier and more expensive, instead of the normal press fit type.
Wheels Manufacturing makes many types of bottom brackets to fit almost every BB specification, you need to choose the correct one to match your frame and also your crankset.
BBright is based on Press Fit 30 specifications, in terms of diameter. However, the offset of the left and right side is non-standard.
This bottom bracket has a bearing with an inner diameter of 24 mm to fit Shimano crank spindles. BBRIGHT-OUT-1 is what you need for this Cervelo Aspero, for Shimano cranksets.
This is what comes in the box.
The left and right side threads together, to eliminate free play and creaking within the frame.
Sealed bearings with an inner diameter of 24 mm, to match Shimano crank spindles.
Set of seals and spacers. The two seals on the left are compulsory, to be placed on the outside of both sealed bearings. Spacers are optional depending on your frame requirements.
Bearing seal placed on the sealed bearings.
Bottom bracket with seals weigh 143 grams, which is quite a bit heavier than normal press fit bottom brackets. Most of the additional weight is due to the aluminium housing.
Non drive side flange is only 1.5 mm thick.
Drive side cup is about 9 mm wide, which compensates somewhat for the shorter BB shell on the right side.
Cup diameter that fits into the frame shell is just under 46 mm. The dimension on this threaded type press fit BB is slightly smaller than normal true press fit type, as there is no need to be very tight since it will be threaded together anyway.
Normal BB tools will not fit as the serration on the BB cups are bigger than usual.
A new tool is necessary, which has a bigger serration to fit this bottom bracket. I bought it together with the new bottom bracket from Wheels Manufacturing.
This side of the tool with a diameter of 44 mm is the same as Shimano standard.
This side with the larger 48 mm diameter serration is for this new BBright bottom bracket.
New tool is needed to install this new bottom bracket.
Non drive side cup is tight and need to be pressed into the frame using a press fit tool.
Drive side cup is slightly looser, and can be placed into the frame by hand.
Once the threads in the middle of the bottom bracket contact each other, just rotate the bottom bracket to tighten them together. For my case, the non drive side cup fits tightly with the frame, so there is no need to hold that side. I only needed to use the tool to rotate and tighten the drive side cup. Once the cups are nicely tightened to each other, installation is complete!
Hopefully this bottom bracket will prevent any bottom bracket creaking on the Cervelo Aspero.
Hi - I was curious how this worked for you? Any creaking?
ReplyDeleteNo creaking at all, perfect after 1 year of riding.
DeleteHi. How many spacers did you use on the drive side cup? It seems to be narrower than the stock cup the bike came with
ReplyDeleteI added 1 mm spacer on the drive side. More details here. https://handsonbike.blogspot.com/2020/05/cervelo-aspero-off-road-riding.html
DeleteWhat SRAM 1x cranksets will fit the Bright BB?? How do I know? They all state GXP? Help!
ReplyDeleteHi is the outside of the bearing 37 or 37.1 mm
ReplyDeleteThanks for sharing!
ReplyDeleteJust wondering how did you made sure to have 34-50Nm without using the socket and wrench? Just wondering if I can do the job without the socket :)
I couldn't check the torque, just by feeling. It is a very high torque so just make it tight.
DeleteIn your 3rd paragraph, you state that it's the non-drive side that extends 11mm out from the frame when in fact it's the drive side that does this. The last photos of the BB clearly show this.
ReplyDeleteThe BBright frame extends 11 mm more on the non-drive side than the drive side, relative to the centreline of the frame. To balance the crankset position, the drive side BB adapter is thus 11 mm longer.
DeleteHi, thanks for this info, super helpful. I'm curious what you put on the bottom bracket before installing- grease or anything? Thanks!
ReplyDeleteI always use grease, so that if it does move slightly, it does not creak.
DeleteHi good article can you simply knock the bearings out to replace them without removing the whole bb assembly from the frame
ReplyDeleteThanks
I'm not sure about that.
DeleteTelboy - I just went through this exercise myself. My 2021 Aspero had 100 miles on it when the drive side bearing gave out. I bought a pair of ABEC-3 bearings from Wheels Manufacturing and installed them in the OEM BB. 5 miles later they were grinding, creaking and chirping (yep - that's a new one for me!).
ReplyDeleteI purchased the Wheels Manufacturing BBRight bottom bracket with ABEC-5 bearings (angular) and installed it this morning. I then rode this morning on a combination of road and single track. After 40 miles, the crank feels perfect. Perhaps the placebo effect, but I'd swear the crank spins more freely now. My suspicion is that the OEM BB compresses the bearings and distorts/destroys them.
So, my advice to any owner of a Cervelo Aspero is to replace the BB immediately with a high quality replacement. I like the Wheels Manufacturing price/performance but there are certainly other options as well. I just think Cervelo cheaped out here and the OEM part just isn't viable.
Hope this helps!
Any tips on removing the old BB on the non drive side?
DeleteI've had a lot of trouble with my Sram GXP BB. I've got a SRAM Force QUARQ PM so the drive side needs that 1/2" clearance to work. Tried knocked out the bearings and replacing but they still make a ton of noise. Spin great, but as soon as I apply watts, it's a mess. My Aspero BB is an internal threaded and still haven't figured out what to do. LBS said Cervelo is reporting the stock BBs are out of stock.
ReplyDeleteWhat tool is used to remove the original bottom bracket?
ReplyDeleteYou can use a press fit removal tool such as this. https://handsonbike.blogspot.com/2022/06/toopre-press-fit-bottom-bracket-tool-set.html
Delete