Should I move the shim over to the non drive side.

[Gillstay]

I have fitted all Tiagra parts and the bottom bracket to a 58 mm bike and the front changer just wont go far enough out.

Shimano recommend two spacers on the drive side as in the photo and so I am thinking of taking one of them off.

Do I then need to have it on the non drive side ? Thank you.

 

[Cycleops]

If it fixes the problem for you give it a go.
Are you coming from a ST BB?

 

[Ajax Bay]

Far too shiny for a ST crankset!
BB-MT800 for SHIMANO 24mm MTB cranks.

 

[Yellow Saddle]

I have fitted all Tiagra parts and the bottom bracket to a 58 mm bike and the front changer just wont go far enough out.

Shimano recommend two spacers on the drive side as in the photo and so I am thinking of taking one of them off.

Do I then need to have it on the non drive side ? Thank you.

View attachment 720289

Surely you mean 68mm, as in 68mm bottom bracket with?

 

[fossyant]

Thats a triple chainset. Have you a triple compatible front mech too ?

 

[Gillstay]

Surely you mean 68mm, as in 68mm bottom bracket with?

Yes, that's rushing as my tea was ready. Sorry. 68mm it is.

 

[Gillstay]

Thats a triple chainset. Have you a triple compatible front mech too ?

Yes I have and the chain almost goes up on to the large chain ring, but not quite.

 

[Gillstay]

Thats a triple chainset. Have you a triple compatible front mech too ?

Will double check, I feel certain its what I ordered.

 

[wafter]

Are all those spacers correct for that crank? Are you getting full engagement between the spline on the crank axle and NDS crank arm? I was under the impression that road cranksets typically had shorter axles to be used on narrower (68mm) BB shells..

 

[fossyant]

Are all those spacers correct for that crank? Are you getting full engagement between the spline on the crank axle and NDS crank arm? I was under the impression that road cranksets typically had shorter axles to be used on narrower (68mm) BB shells..

A pic of the non-drive side axel with the crank removed would be good, as I think you may not have enough of the splines showing, which will cause load issues on the bearings.

 

[Deleted member 121159]

Yes, that's rushing as my tea was ready. Sorry. 68mm it is.

If using a 68mm BB on a 68mm BB shell, the spacers shouldn't be used? Check Shimano manuals but as far as I know you shouldn't use that many spacers.

Edit: I see what the issue is from the pic. You've got a 73mm BB which has a wider sleeve than a road BB, so you can't install it without spacers. You need a shorter sleeve which you might have lying around or a new BB that's road specific.

 

[Gillstay]

Thank you folks that gives me a few things to check through. Will get busy and report back.

 

[Cycleops]

Are all those spacers correct for that crank? Are you getting full engagement between the spline on the crank axle and NDS crank arm? I was under the impression that road cranksets typically had shorter axles to be used on narrower (68mm) BB shells..

Hollowtech uses outrigger bearings and as such the 2 piece cranks have to fit both sizes of BB, hence the spacers.

 

[wafter]

A pic of the non-drive side axel with the crank removed would be good, as I think you may not have enough of the splines showing, which will cause load issues on the bearings.

Indeed, or just the NDS crank arm with the threaded plastic preload plug removed. I think for this crank length no spacer should be used; which may or may not require another (road specific) BB..

Hollowtech uses outrigger bearings and as such the 2 piece cranks have to fit both sizes of BB, hence the spacers.

Yes; however road BBs fit directly to a 68mm shell with no spacers, MTB BBs fit directly to a 73mm shell or 68mm with spacers. Assuming that IIRC the effective width (or length, if considered with respect to crank axle length) of all BB cups / bearing assys are the same, the MTB BB assy when fitted will be 5-6mm wider than the road offering, and as such the crank lengths should also differ.

As such I think the OP has fitted the incorrect MTB-spec BB to his 68mm shell for the road-based groupset they're using. In theory they should just be able to remove the spacers; however in practice there might be issues with thread depth.

If this isn't resolved by the time I get home I can crack out the measuring stick as I have examples of both road groupset / road BB / 68mm shell and MTB groupset / MTB BB / 68mm shell..

 

[wafter]

My post above seemingly corroborated here:

Mountain external bearing crank spindles are longer than road spindles, and their respective bottom brackets are sized to fit one or the other. Shimano BBs have a plastic sleeve joining the two cups that protects the bearings from water dripping down from the seatpost opening and other contamination. That sleeve is a fixed length, so that if it's to be used the cups have to be that far apart from each other (give or take a tiny margin for variance from the exact nominal shell width, i.e. 67.95mm)

So in summary, BB is wrong for the crankset being used; safe answer is to replace the BB with a proper road-specific item, bodge might be to replace the placcy sleeve inside with a shorter road item and remove the spacers.

As above this can be confirmed by looking at the axle / NDS crank arm engagement under the preload cap, and / or measuring crank axle length and BB width for comparison to known-correct items.