leafsun

Hi guys, my bike frame is Wilier Imperiale with Campagnolo crankset but now I am changing it to Shimano 6800. The bottom bracket does not fit to the Shimano one.It is old version WILIER OVERSIZE BOTTOM BRACKET. I searched it but someone says it is BB94 while someone says it is BB90. I am quite confused about the real specification of the bearing cups. Now I don't even know what key words I should use to search the replacement item to buy.... Thanks.

AnkleWork

What does the manufacturer say?

Maybe someone could measure it.

trailflow1

Read this chart. Wilier BB94 can be found at the bottom

https://wheelsmfg.com/bb-standards

BB94 and BB90 relates to the shell width. These number are not important. They both use the same 37mm OD bearings.

The inner width of the shell hole is the measurement you need. And whether it uses a plastic sleeve or not. Remove the crank and take a look.

If the bearings press directly into the metal bb shell. The bearing should be 37mm wide. For the Shimano 24mm spindle cranks then you need 37x24x7mm bearings also called 2437 bearings. Bike brands will sell you these re-badged as BBxx bearings.

If the bb uses a plastic sleeve measure it's width and post info here.

tomtomtom123

You should measure your BB shell. What is the width and inner diameter of the shell?
If it's meant for Shimano cranks, it would be 41mm inner diameter, and either 86.5mm wide for road or 91.5mm for mtb (Shimano and bikegremlin says 92.0mm), according to this site:
https://wheelsmfg.com/bb86-92-tech
https://bike.bikegremlin.com/1712/ov...-bb-standards/
It says BB86 standard is for the 86.5mm width shell, and BB92 standard is for 91.5(92.0)mm width shell.

BB90 is something different. It's a proprietary direct press bearing system for Trek.
https://wheelsmfg.com/bb-standards
https://www.parktool.com/blog/repair...nd-terminology

SM-BB94-41A is the model number of the press fit BB that Shimano sells for BB92 shells (and 89.5mm shells with the addition of a 2.5mm spacer). There are also other cheaper models on the list.
https://productinfo.shimano.com/#/sp...LLOWTECH%20II)

SM-BB92-41B is the model number of the press fit BB that Shimano sells for BB86 shells. There are also other cheaper models on the list.
https://productinfo.shimano.com/#/sp...LLOWTECH%20II)

What's important is the overall width from dust cap to dust cap on the BB.
On 68mm BSA shells, the threaded Shimano road BBs are 11.5mm thick, so 68+11.5+11.5 = 91.0mm overall width.
On 68mm BSA shells, the threaded Shimano MTB BBs are 10.5mm thick with 3x2.5mm spacers, so 68+10.5+10.5+7.5 = 96.5mm overall width.

The press fit BBs may be a little bit different in overall width, but they need to be very close to the BSA BBs in order for the same spindles to give you the same chainline.

Here is the instruction manual from Shimano. On page 20 it shows press fit BB for both road (86.5mm BB86) and MTB (92mm BB92), including 89.5mm shells with 2.5mm spacer. Page 10-11 shows threaded BSA, but only for MTB, doesn't show road.
https://si.shimano.com/pdfs/dm/DM-FC0002-12-ENG.pdf

I've never had a MTB bike before, so I'm not sure, but it seems that Shimano MTB cranks might have a 2.5mm offset built into the crank, so that's why 68mm BSA shells have 2.5mm spacer on the left side and 5mm spacers on the right side. I don't know if a BB92 (92mm shell) bottom bracket already has the offset built into it, or if the shell itself is offset. But an 89.5mm shell needing a 2.5mm spacer means either the 89.5mm shell is offset or else either the 89.5mm or the 92mm shell will be offset while the other is centered to the frame. Or if I'm completely wrong, then it means that the MTB cranks are just not symmetric.

leafsun

Thanks mate. Your information is helpful. Let me try to find the proper bearings to make a change. Result will be posted once done

davidad

https://www.ebay.com/itm/ENDURO-MR24...wAAOSwXI1cR29x The LLU seal is most effective in keeping crud out.

leafsun

I found a 2437 Enduro bearing and it fits the BB shell, only a little bit loose, which I believe it is a same problem as Trek, not a big deal. However, now the problem is the plastic sleeve (or called bearing cup?). The plastic sleeves for Trek's BB90 is 2mm thickness (measured by ruler, not accurate), but in Imperiale's BB94, these sleeves are not thick enough. They need 2mm more thick on each side (94mm-90mm). Is there any kind of plastic sleeve that thick? The second option is to use two 2mm thickness sleeves to press the bearings in the middle. But I doubt it will increase the friction.

As I have another bearings of 6805 in hands from my orignial Campagnolo, it is both ok whether its internal diameter is 24mm or 25mm. I just need a thick enough plastic sleeve on 2437 bearings or a thick enough adatper on 6805 bearings. Is it more difficult than find a right bearing?...

Another clue has just come from Wilier HQ, they tell me to find 'BB Shimano AV469H for the Imperial model', but I cannot find any thing with these key words. Can it give you some ideas?

And I found 'Repair Pack for 24mm (Shimano) Bottom Brackets' on WHEELSMFG. Does it what I need?

tomtomtom123

Why haven't you measured your bottom bracket shell?

tomtomtom123

It's difficult to understand what you're trying to do, but I tried reading your text again to decipher it.

Firstly, what BB shell do you have? You never mentioned it.

Going by what you said, you pressed a 24mm inner diameter x 37mm outer diameter cartridge bearing directly into the BB shell. Therefore, it is impossible to use a BB cup, because a BB cup is meant to go in between the bearing and the shell. If your bearing is touching the radial inner surface of the shell directly, then it is impossible to insert something in between the 2 surfaces. Going by what was mentioned by others previously and the WheelsMfg website, you might have a special rare Wilier BB94/93 shell, which WheelsMfg says is 93mm outer width. Are you sure you have 94mm as you have said?

Whether you have a 93mm or 94mm shell width, your first problem is that Shimano road cranks are designed to have around 91mm overall BB width from the dust cap to dust cap, or at least this is what I have with my Shimano road BSA threaded BB cups. Can your Shimano cranks insert itself 1mm or 1.5mm past each end of the shell? If not, then if you have to leave a gap of around 0.5mm between each crank arm and the end of the shell, then you will have to measure the thickness of the seal (end caps / dust caps) that you're using in between the cartridge bearings and the crank arms, and add some thin spacers (only if necessary) in between seal and the crank arms, to try and get either 93+1=94mm or 94+1=95mm overall width. However, because Shimano road cranks want 91mm, then you will be either 95-91 = 4mm or 94-91 = 3mm too wide. You might be able to get away with this, but it will mean your chainline is moved 1.5mm to 2mm outwards from where Shimano says it should be (which might be acceptable), and your left crank arm will have 3mm to 4mm less splines at the end of the spindle to engage, which is quite a lot of difference (depends on what you think is acceptable).

Your second problem is the location of the cartridge bearings inside the shell in relation to the spindle bearing surface. There are 2 widths of polished areas on the Shimano spindle, which are where the cartridge bearings is supposed to contact. Just because Trek BB90 is similar to Wilier BB94/93 does not mean that the bearings are in exactly in the same location with both systems (as you claimed). I would imagine that the Wilier BB94/93 would have the bearings spaced wider apart since it has a wider BB shell. However, if what you say is true, that the location of the bearings are exactly the same, then you might have a problem with the bearing location in your Wilier BB94/93, since the cartridge bearing is deeper from the outside end of the shell. If this is the case, then the right side bearing surface of the spindle will be offset from the cartridge bearing by 1-2mm, however the left side bearing surface would be offset even further if you need to space the overall BB width wider to clear the wider BB shell. 1mm to 2mm (bearing inset from the end of the shell) + 3mm to 4mm (extra BB shell width) = 4 to 7mm total offset of the left bearing surface of the spindle to the cartridge bearing. Depending on how it works out, the left side bearing surface of the spindle might not even touch the cartridge bearing. You should check whether or not this is the case.

Anyway, I would imaging you want "LESS" spacers, not more spacers, in order to get a narrower overall width, as close to 91mm as possible. But if the crank arms cannot clear the wider 94mm BB shell, then you might need to add some spacers to the seal (dust cap). The WheelsMfg repair kit that you mentioned comes with 1mm and 0.5mm spacers, along with a seal (dust cap). You could give it a try. Otherwise, you can buy 10 pack of spacers by themselves without the seal.

https://wheelsmfg.com/products/repai...-brackets.html
https://wheelsmfg.com/24mm-id-x-1mm-...r-10-pack.html
https://wheelsmfg.com/24mm-id-x-0-5m...r-10-pack.html

Also, the only "sleeve" is the water/dust sleeve that goes in between BB cups to prevent water from reaching the cartridge bearings through holes in the shell, but since you have direct press cartridge bearings, there are no BB cups to add a sleeve to.

Also, it doesn't make sense to use 25mm inner diameter cartridge bearings with 24mm spindles. How would you shim the gap from the 1mm difference in diameter? Unless you have some dust caps for Shimano bottom brackets. According to the website below, the older larger diameter Shimano bottom brackets (the newer high end bottom brackets use smaller outer diameter) are 25x37x7mm.
https://www.mountainbikerides.co.uk/f...placement.html

However, other people report that it's actually 25x37x6mm.
https://weightweenies.starbike.com/f...ic.php?t=38320

The Shimano dust cap does have built in insert that fills in the extra 1mm gap between the cartridge bearing and the spindle bearing surface.

tomtomtom123

Here, if you want to use your 25x37x6mm or 25x37x7mm bearings, you can buy these dust caps, or else go to a local bike shop that has used Shimano BBs in the trash and ask them if you can take the dust caps from them.

According to the Starbike forum thread, the 7mm dust cap is for the 6mm wide bearing because the cap itself is 1mm thickness in width. But I don't know if this applies to the Phill wood dust cap. If your bearings are 7mm, then you might go for the 8mm dust cap. But I'm not sure. You can email them to ask.
https://phil-wood-co.myshopify.com/p...iant=565755425
https://www.universalcycles.com/shop...s.php?id=47039

Or buy these cheap chinese ones.
https://www.aliexpress.com/item/4000043314276.html

If you're getting an overall width greater than 91mm and can insert the crank arms deeper than the 94mm shell, then you might want to use the narrower 6mm cartridge bearings, to get as close as possible to 91mm. You should take some measurements first to find out which case applies.

leafsun

I believe I mistook mixing English words PLASTIC SLEEVE, DUST CAP, SPACER and SEAL into one thing so make my words hard to be understood. I have installed the Ultegra crank but I am not sure whether it is the best way. I am now trying to explain what I was facing and my solution as best as I can. (sigh, language is a big issue)

1. The dimension of the Wilier Imperiale BB94 is 94mm width and 37mm diameter. The Wilier's original solution for Shimano crank is to use a 25*37*7 bearing and a 24*37*1 plastic sleeve to make the bearing fit Shimano spindle. I believe the reason Wilier choosing to use a 25*37*7 bearing is cost control that they don't need to prepare different bearings for Shimano users and Campagnolo users.

2. I guess (as I never used Trek before) the dimension of the Trek BB90 is 90mm width and 37mm diameter. The Trek's original solution for Shimano crank is to use a 24*37*7 bearing and a 24*41*1 dust cap. The dust cap is not designed to insert into BB shell. It is designed to cover the shell fully from outside. Therefore, the whole width of this COMPOSITION (I am sure whether this is an correct English word) is 90mm (BB shell) plus 2*1mm (two dust caps 1mm thickness) into 92mm.

3. Therefore, the whole width will be too long for Shimano spindle if the Trek BB90 package is applied into Wilier BB94. The dust cap cannot be inserted into the BB shell so the whole width will be 94mm (BB shell) plus 2*1mm (two dust caps 2mm thickness) into 96mm. Moreover, there is a 1mm width space between the bearing and the dust cap.

4. The Trek BB90's 2437 bearings are applied for use but the dust cap cannot be used in Wilier Imperiale frame, so I made an order to a plastic factory for two custom-made silicon seals with dimension 24*37*1. They can be inserted into the BB shell completely so the whole width of this COMPOSITION is 94mm without any extra outer part. Ultegra crank can be installed perfectly.

5. I am not sure whether these two custom-made seals can prevent water and dirt effectively. However, as this frame's BB shell is 94mm width, it means orignially Wilier didn't expect to make any REAL dust caps cover outside from BB shell as 94mm length is the maximum length for Shimano 6700 crank's spindle already. I don't have any experience of using custom-made small parts before. I am wondering whether the seal inserted into BB shell can take effect on preventing water and dirt as good as dust cap covering outside from the BB sheel? Physically, I doubt it. Maybe there is some better solution for this BB?

I have drawn illustration for my explanation but apparently my authority is not high enough to upload files.

smashndash

Are you sure that Wilier originally used plastic sleeves (aka “reducers”) for Shimano cranks? I have a hard time believing this because this would mean that the axial preload system (the one that works by tightening the large plastic bolt by hand) presses against those plastic sleeves. If those plastic sleeves are pressed in, it would be impossible to get any real axial preload.

Can I ask why Enduro 24x37 bearings are not being used?

https://wheelsmfg.com/enduro-24-x-37...d-bearing.html

I guess it is because you want to use some sort of dust cap? As you have concluded, I don’t think this is possible. I think the integrated bearing seals are enough for most cases as long as you don’t pressure wash or use too much soap.

leafsun

Yes, Wilier's official manual clearly shows it uses plastic sleeves for both Shimano and Campagnolo crank. I cannot upload any URL or illustartion. You can google with key words "Wilier-Cento-Uno-bb-diagram.pdf".

You remind me one thing. If Wilier was using the same 2537 bearings for both cranks, there is no need to apply plastic sleeve for Campagnolo's, unless it was using 2637 (I doubt whether it exists) for CP. If so, it means the reason Wilier choosing 2537 bearings for Shimano is not for cost control but for using plastic sleeve deliberately. Wilier maybe hopes the plastic sleeve can take the same effect as dust cap?

I may not wrote clearly. I am appling Trek's BB90 bearings 2437 for my frame but the 2441 dust cap in the pack cannot be used. I used two custom-made 2437 seal for my frame to take the effect as spacer, and dust preventing (if it can).

You mean the Enduro sealed bearings can prevent water and dust effecetively by itself? If so, it relieves my concern. But it goes back to my first assumption. If sealed bearing can prevent dirt and water, why Wilier insists on using plastic sleeves deliberately but not using correct bearings, even sacrificing axial preload system (if your point is correct)?

Interesting.

smashndash

Can you post a link to that PDF? I can’t see it in my search results. Modify the link a bit if the website won’t let you.

https://www.twohubs.com/pdf/Wilier-C...bb-diagram.pdf

^is this it?

The plastic sleeve is good because then the crank spindle will not wear out if it slips in the bearings. This is why Shimano made its spindle 24mm. It is supposed to be used with 25mm bearings and a sacrificial plastic reducer. BTW 25x37 are also known as 6805 bearings.

It’s definitely better to have a dust cap if you can fit one. Please post a picture of your custom dust caps when you get the chance.

According to that diagram, the Campagnolo system would not have any dust caps.

Also, it seems that there is enough space to use dust caps with Shimano according to that diagram.

See here: https://www.twohubs.com/Product/wili...8#.Xmclm8BlAlQ

^email these guys if you have any questions.

leafsun

Yes, this PDF file is the one. I mistook reading Sram into Campagnolo. Yes, there is no dust caps or seals for CP crank.

My custom dust cap is an O-shape spacer with ID 24mm, OD 37mm and thickness 1mm. Shape is normal as usual, but I am not sure whether the chemical composition is the same as brands manufactory made. I ordered four kinds of dust caps. The main composition of them are polyurethane, silicone, poly tetra fluoroethylene, and fluorelastomer separately. The mechanician tried poly tetra fluoroethylene ones first but found it made noisy when crankarms rotating. Then he chose silicone ones RANDOMLY. I think only materials professions can tell whether he made the best choice.

tomtomtom123

Instead of making your own sleeve insert to fill the gap between the 24mm spindle and 25mm inner diameter of the bearing, why not use the dust cap from a Shimano hub and insert it on the inside of the bearing? Then you can put something like a 78-80mm long tube with an inner diameter of 24.5mm in between the dust caps.

Or if you really want a dust cap on the outside of the bearings, then you should just have it on the outside of the shell without touching the spindle or the bearings. I really don't know what your shell looks like. You still haven't shared any pictures.

leafsun

I am looking forward to share links and pictures but this forum has rigid limit for new users. I don't have authority unitl now.

I ordered custom-made O shape seals. It is not plastic sleeve (or called reducer). My bearings are 24mm ID so it is no need to reduce the diameter. I expect the custom to take effect as dust caps and spacers.

The width of BB shell is 94mm. I cannot put any dust caps out from the BB as 94mm is the maximum allowed length for Ultegra spindle already. That is why I have to throw away the dust caps with 41mm OD of the kit of Trek's BB90 replacements but ordered two custom seals with 37mm OD, which is just the diameter number of bb hole.