Xt bottom bracket s...
 

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[Closed] Xt bottom bracket spacers, do I need them?

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Just received my new chainset and BB and the bottom bracket has 3 plastic o rings with it. Firstly where do these go and how do I know if I need them?


 
Posted : 17/08/2011 3:49 pm
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You definitely need at least one. If your BB shell is 68mm wide then you need 2 on the driveside and one on the non-drive. If your BB shell is 73mm wide then you only need one on the dive side. They mount between the cup and the BB shell.


 
Posted : 17/08/2011 3:51 pm
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68mm shell 2 on drive side, one non drive side.

73mm shell one on drive side.

(assuming no funny mechs or chain devices involved)


 
Posted : 17/08/2011 3:51 pm
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I'd ignore the above and add 3 if you have a 68mm BB or 1 if you have a 73mm BB. Put them in whatever order gets you the best chainline, there is no set rule.


 
Posted : 17/08/2011 3:52 pm
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According to Shimano there is!


 
Posted : 17/08/2011 3:55 pm
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Many thanks guys, it's a 73mm so jut put the one on the drive side, see how that goes


 
Posted : 17/08/2011 4:36 pm
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Did the chainset come without instructions?


 
Posted : 17/08/2011 4:39 pm
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Or put one on the non drive side and see how that goes?

Put it on whichever gives the best chainline.

According to Shimano there is!

I dont think its a set rule!


 
Posted : 17/08/2011 4:39 pm
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Yea the chainset came without instructions, saved a packet though!


 
Posted : 17/08/2011 4:42 pm
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I dont think its a set rule!

This.

I have a DW link 5 Spot & have put one on the non drive side only. As recommended by Turner bikes.


 
Posted : 17/08/2011 4:43 pm
 anjs
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I have a DW link 5 Spot & have put one on the non drive side only. As recommended by Turner bikes

Which is the same as Shimano 😀

If you are running a triple shimano chainset you will want a 50mm chainline. The only reason you would move the spacer(on a 73mm shell) to the non drive side is if you had a 2x9.


 
Posted : 17/08/2011 6:34 pm
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[b]davidtaylforth - Member :"I'd ignore the above and add 3 if you have a 68mm BB or 1 if you have a 73mm BB. Put them in whatever order gets you the best chainline, there is no set rule."[/b]

as a professional bike mechanic, I'd advise you to ignore this advice^^

the non-driveside Shimano cup has considerably less thread depth than the driveside cup...

...and adding too many spacers to the non-driveside can leave your cup hanging off a couple of threads

potentially ruining your frame's bottom bracket shell, and definitely ruining the bottom bracket cup 🙁

for 68mm its 1 spacer on the non-driveside, and 2 spacers on the driveside

for 73mm its 1 spacer on the driveside, and no spacers on the driveside


 
Posted : 17/08/2011 6:41 pm
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[i]If you are running a triple shimano chainset you will want a 50mm chainline. The only reason you would move the spacer(on a 73mm shell) to the non drive side is if you had a 2x9.[/i]

I run the single spacer on the non drive side with 3x9 as it gives a much much better chain line for my set up though i lose some tyre clearance in granny with front mech.


 
Posted : 17/08/2011 6:42 pm
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I run the single spacer on the non drive side with 3x9 as it gives a much much better chain line for my set up though i lose some tyre clearance in granny with front mech.

How is it better? Come on share the info 😆

I get paid to fit this stuff every day and manufacturers specs rule the roost


 
Posted : 17/08/2011 7:10 pm
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better in that it lines up nearer to the center of the block when in the middle ring without it on the drive side.


 
Posted : 17/08/2011 7:20 pm