XT Boost cranks in non boost frame

[whichway]

I want to buy a LR power meter and they are all based on boost cranks.

Can I install a shimano XT boost crank in a non boost frame (11 speed, but that should be OK) and will it work OK.

Can I get a chain ring setup that works for this?

Is the Q factor different?

I can't find anything on crank dimensions etc

 

[bear the bear]

Yes, and the difference is 3mm

 

[creaky]

Deja vu? Wasn’t this exact question asked recently?

 

[moorey]

Felix runs this without any dramas.

 

[moorey]

Deja vu? Wasn’t this exact question asked recently?

Didn’t you already say that?

 

[whichway]

Can I just fit a 3mm spacer between the crank and the chainring so that the chainline is back at the non boost line.

 

[whichway]

Didn’t you already say that?

 

[whichway]

I thought my bike was boost, but it's not. This is about the difference between boost and non-boost, not 11 and 12 speed.

 

[moorey]

Can I just fit a 3mm spacer between the crank and the chainring so that the chainline is back at the non boost line.

I definitely wouldn’t.

 

[moorey]

Sorry, I miss read your original post as non-boost cranks in a booth frame. I still wouldn’t recommend spacing out the ring by 3 mm.

 

[Ultra Lord]

Sorry, I miss read your original post

 

[moorey]

View attachment 365223

Reporting. I want to speak to the manager.

 

[Ultra Lord]

Reporting. I want to speak to the manager.

You are the manager?
Moderating this place must finally be taking it’s toll on you.

 

[bear the bear]

Can I just fit a 3mm spacer between the crank and the chainring so that the chainline is back at the non boost line.

No, boost chainrings/ cranks are offset outboard by 3mm. Installing a spacer on the drive side will push it further outboard.

 

[Halo1]

I thought my bike was boost, but it's not. This is about the difference between boost and non-boost, not 11 and 12 speed.

Now every pedal stroke you are going to be thinking would this be better with boost. New bike time.

Thanks for asking as this is helpful for me as I have both a boost and non boost frames.

 

[PJO]

Can I just fit a 3mm spacer between the crank and the chainring so that the chainline is back at the non boost line.

I don't see why not, you mean something like this (spacers in red, chaingring in green)?

 

[PJO]

I'm currently running a non-boost crankset in a non-boost frame with 1mm spacers because I wanted the chainline to be 49mm and the original was 50mm.

Just need longer chainring bolts

 

[bear the bear]

I don't see why not, you mean something like this (spacers in red, chaingring in green)?
View attachment 365224

This probably won't work, as 3mm of spacers will push the chainring past the tabs and the ring will be "floating" on the bolts alone.

 

[whichway]

This says 8120 chainline is 55mm.
https://bike.shimano.com/en-NZ/product/component/deore-xt-m8100/FC-M8120-1.html
This says the 8000 chainline is 53.4mm
https://bike.shimano.com/en-EU/product/component/deorext-m8000/FC-M8000-B1.html

Does this mean that the difference in chainlines between 8000 non boost and 8120 boost is only 1.6mm?

Also with the direct mount I didn't think there were any bolts for the 1x shimano.

 

[Chriso_29er]

This says 8120 chainline is 55mm.
https://bike.shimano.com/en-NZ/product/component/deore-xt-m8100/FC-M8120-1.html
This says the 8000 chainline is 53.4mm
https://bike.shimano.com/en-EU/product/component/deorext-m8000/FC-M8000-B1.html

Does this mean that the difference in chainlines between 8000 non boost and 8120 boost is only 1.6mm?

Also with the direct mount I didn't think there were any bolts for the 1x shimano.

That is the difference between M8000 'boost' and the 8120 ' boost'

New Gen shimano is hella confusing. Apparently now 52mm chain line M8100-1 will work with both non-boost and boost! Used to be 50.4mm Sounds to wide for non-boost to me. But may be due to differences with cluster position on microspline?
Then you have 55mm 'boost' M8120-1 and 56.5mm M8130-1'super boost'