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My bottom bracket shell is 68 mm English thread.

I put a 1 mm spacer on the drive side BB to move the chain rings further away from the frame, so to prevent the chain rub against the inside of the front derailleur cage when the chain is on the small front ring and largest rear cog.

I have already adjusted the FD limit screws, there is no way the FD can go any further to the frame.

Before I adding the spacer the rub is very obvious. After adding the spacer the rub is very minor but I want to eliminate it.

Should I　add one more 1 mm spacer on the drive side? I already added another 1 mm spacer on the non-drive side because left crank will rub the kick stand without it. So I already put total of 2 mm spacers on the BB.

Can I add one more on the drive side?

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  • This link describes what spacers you're supposed to be using. You're not using the right number or size of spacers as is. – Batman Jun 4 '15 at 11:53
  • Thanks. Mine is road crank (5700), so there should be no spacers used. But as I said I used the spacers to eliminate chain rub. There should be some 'tolerance' for spacers as there should always be. – thotwielder Jun 4 '15 at 13:30
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On M542 crank set and 68 mm BB shell, I use one spacer on the left, and 2 on the right.

I think that on 68 mm shells you always use all 3 spacers, and distribute them on the left/right side to get chain line you need.

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The solution is not in more spacers but a wider bottom bracket spindle. If you put too many spacers in your BB it will loosen easier and potentially cause more damage to you and your bike. I would take your BB off and bring it to your LBS and have them measure it and get you the next size or two (depending on how bad the chain rub is). You may have a bb that is 68X110 so you would need a 68x113 or 115 or even 118. Hope this helps!

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  • The crank is Shimano 5700, hollowtec 2, so no spindle. – thotwielder Jun 4 '15 at 14:19

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