Quick bottom bracket question

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Lookryder
Posts: 73
Joined: Sun Aug 06, 2017 12:37 am

by Lookryder

I just had work done on my bike to have a new 12-speed ultegra crank installed. I noticed after I got home that there is a 1-2 mm gap between the non-driveside crank arm and the bottom bracket (T-47) where you can see all the way to the spindle; is this normal? I don’t remember there being this big of a gap before and am wondering if there should normally be a spacer or something there to fill the gap so debris doesn’t get in.

Thanks in advance.

by Weenie


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edchristoph
Posts: 110
Joined: Sun Aug 18, 2019 10:40 am

by edchristoph

If there is a 1-2mm gap between the NDS crank and the BB you should have very noticeable side-to-side movement, i.e., play, in your crank. Do you have a photo?

Chris

Lookryder
Posts: 73
Joined: Sun Aug 06, 2017 12:37 am

by Lookryder

Not right now as I’m at work, but can get one tonight. I didn’t noticed much play when I rode home from the shop, but it was only 5 miles.

Karvalo
Posts: 3444
Joined: Fri Aug 10, 2018 6:40 pm

by Karvalo

You definitely shouldn't be able to see the spindle on a Shimano install. The crank arm should butt directly onto the bearing shield. What bike frame is it? Trek, by any chance?

Lookryder
Posts: 73
Joined: Sun Aug 06, 2017 12:37 am

by Lookryder

Karvalo wrote:
Thu Aug 18, 2022 4:39 pm
You definitely shouldn't be able to see the spindle on a Shimano install. The crank arm should butt directly onto the bearing shield. What bike frame is it? Trek, by any chance?
It’s a Factor Ostro

Karvalo
Posts: 3444
Joined: Fri Aug 10, 2018 6:40 pm

by Karvalo

Lookryder wrote:
Thu Aug 18, 2022 4:43 pm
Karvalo wrote:
Thu Aug 18, 2022 4:39 pm
You definitely shouldn't be able to see the spindle on a Shimano install. The crank arm should butt directly onto the bearing shield. What bike frame is it? Trek, by any chance?
It’s a Factor Ostro
Is it currently setup with the stock BB - an external cup on the DS and internal on the NDS?

kode54
Posts: 3749
Joined: Tue May 23, 2006 9:39 pm

by kode54

Ostro comes with many BB spacers and BB adapters. I'm surprised that the LBS didn't use any.
- Factor Ostro VAM Disc
- Factor LS Disc
- Specialized Aethos Disc
- Sturdy Ti Allroad Disc
- Guru Praemio R Disc

Lookryder
Posts: 73
Joined: Sun Aug 06, 2017 12:37 am

by Lookryder

Karvalo wrote:
Thu Aug 18, 2022 4:54 pm
Lookryder wrote:
Thu Aug 18, 2022 4:43 pm
Karvalo wrote:
Thu Aug 18, 2022 4:39 pm
You definitely shouldn't be able to see the spindle on a Shimano install. The crank arm should butt directly onto the bearing shield. What bike frame is it? Trek, by any chance?
It’s a Factor Ostro
Is it currently setup with the stock BB - an external cup on the DS and internal on the NDS?
Yes everything on it was stock from the factory before they did the replacement.

User avatar
wheelsONfire
Posts: 6283
Joined: Mon Jul 07, 2014 8:15 am
Location: NorthEU

by wheelsONfire

Lookryder wrote:
Thu Aug 18, 2022 4:59 pm
Karvalo wrote:
Thu Aug 18, 2022 4:54 pm
Lookryder wrote:
Thu Aug 18, 2022 4:43 pm
Karvalo wrote:
Thu Aug 18, 2022 4:39 pm
You definitely shouldn't be able to see the spindle on a Shimano install. The crank arm should butt directly onto the bearing shield. What bike frame is it? Trek, by any chance?
It’s a Factor Ostro
Is it currently setup with the stock BB - an external cup on the DS and internal on the NDS?
Yes everything on it was stock from the factory before they did the replacement.
Ofcourse they need to install an adapter if it's not fitted with a BB that is made especially for Shimanos 24mm crank axle!
Bikes:

Ax Lightness Vial EVO Race (2019.01.03)
Open *UP* (2016.04.14)
Paduano Racing Fidia (kind of shelved)


Ex bike; Vial EVO D, Vial EVO Ultra, Scott Foil, Paduano ti bike.

Karvalo
Posts: 3444
Joined: Fri Aug 10, 2018 6:40 pm

by Karvalo

Lookryder wrote:
Thu Aug 18, 2022 4:59 pm
Karvalo wrote:
Thu Aug 18, 2022 4:54 pm
Lookryder wrote:
Thu Aug 18, 2022 4:43 pm
Karvalo wrote:
Thu Aug 18, 2022 4:39 pm
You definitely shouldn't be able to see the spindle on a Shimano install. The crank arm should butt directly onto the bearing shield. What bike frame is it? Trek, by any chance?
It’s a Factor Ostro
Is it currently setup with the stock BB - an external cup on the DS and internal on the NDS?
Yes everything on it was stock from the factory before they did the replacement.
Were they replacing one Shimano crank with another Shimano crank?

Lookryder
Posts: 73
Joined: Sun Aug 06, 2017 12:37 am

by Lookryder

Yes, they were replacing the exact same crank.

edchristoph
Posts: 110
Joined: Sun Aug 18, 2019 10:40 am

by edchristoph

It's hard to judge without seeing it. But if the NDS crank is not kissing the dust cap of the BB bearing this means there is no preload on the bearings. Maybe the spindle is sitting very tight in the bearings and you didn't put down too many watts so you didn't notice it, but there will be play in your crank. If it's not fixed, your BB bearings will wear out in no time.

I see two options: either the shop didn't mount the NDS crankarm properly or they simply forgot a spacer during the reassembly. Both should be very easy to fix.

jih
Posts: 596
Joined: Fri Jan 29, 2016 12:54 pm

by jih

Grab the left crank at the end and pull it sideways left and rightto see if there's any play. If the bearing has no preload, there might be some play in the crank.

Next, try hitting the left crank with the palm of your hand. The whole crankset (both sides) will move to the right if there's a missing adaptor.

Tbh, I'd just get the crank out and try the spacers that came with the bike until one is right. Removing and fitting a hollowtech crank is less work than taking a bike to a shop.

I have a 12s Ultegra crank fitted (on bb86 BB shell and standard Shimano BB). Can take a pic of the NDS crank/BB interface if that's helpful.

Lookryder
Posts: 73
Joined: Sun Aug 06, 2017 12:37 am

by Lookryder

Here’s a pic; maybe there are spacers in there and I’m paranoid, but it does seem like there’s more space there than before I had the crank replaced. Thanks for the replies everyone, I’ll play around with it tonight and report back.
Attachments
F2552CBC-F58A-46FD-87BA-CFF6BF58FEFC.jpeg

Karvalo
Posts: 3444
Joined: Fri Aug 10, 2018 6:40 pm

by Karvalo

That looks like it could well be ok, I don't think that's bare spindle you're seeing. If you can't move the crank laterally in the bike then it's fine.

by Weenie


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