Non boost cranks in...
 

[Closed] Non boost cranks in boost frame - chainring position

Posts: 812
Free Member
Topic starter
 

Hi all,

first new build in a decade so getting my head around all the new standards is exhausting! Its going quite slowly. My new frame is boost spacing and im fitting an old pair of RF Deus cranks. If im right in thinking that a boost chainline is 3mm further outboard than a non boost chainline, would i not be better off fitting the single narrow wide ring on the outside of the crank arm where my bash ring used to be?? If it makes any difference i can space the x type cranks on the spindle between 49-51mm for a normal non boost setup with the tiny spacers. Thanks for any help


 
Posted : 05/02/2020 8:54 pm
Posts: 43889
Full Member
 

I'd try it as normal and see how it goes. Don't get hung up on exact chainline. It'll be better in some gears, worse in others. Lots of folk (including me) are running non-Boost cranks in Boost frames.


 
Posted : 05/02/2020 9:15 pm
Posts: 538
Free Member
 

If the chainring clears the chainstay you'll have better chainline in the lower gears. I run a non-boost crank on a boost frame.


 
Posted : 05/02/2020 9:34 pm
Posts: 0
Free Member
 

I’ve run a non boost crank with narrow wide on a boost frame for over 3 years and never had a single issue, it started life as a 2x10 then converted to 1x10 now 1x12. Id try it on the inside first, I’d have a bet that it will work.


 
Posted : 05/02/2020 9:36 pm
Posts: 17771
Full Member
 

One of my bikes runs a non boost crank with a boost rear end.
As long as the chainring doesn't touch the frame it'll be fine.
I think the chainline is actually better like this anyway.


 
Posted : 05/02/2020 9:41 pm
Posts: 5043
Full Member
 

I also run standard cranks in a boost frame.
Deore triple, with the big ring removed, the 32T middle ring in its normal position, and both the BB spacers on the drive side.
This is on a surly karate monkey.


 
Posted : 06/02/2020 8:27 am
Posts: 4277
Full Member
 

It’ll be better in some gears, worse in others

I think the chainline is actually better like this anyway

Agreed - with non-boost cranks and a boost wheel, you're improving the chainline in the bottom gears, which I would argue you are normally pushing far harder, and for longer than your top gear.


 
Posted : 06/02/2020 9:22 am
Posts: 0
Free Member
 

I’d try it as normal and see how it goes. Don’t get hung up on exact chainline. It’ll be better in some gears, worse in others. Lots of folk (including me) are running non-Boost cranks in Boost frames.

If the chainring clears the chainstay you’ll have better chainline in the lower gears. I run a non-boost crank on a boost frame.

I concur. If it clears the chainstay, I certainly wouldn't worry about it. Might get a bit graunchy back pedalling in top gear.


 
Posted : 06/02/2020 10:10 am
Posts: 812
Free Member
Topic starter
 

cool, thanks will leave it as it is and go from there..


 
Posted : 06/02/2020 10:26 pm
Posts: 6332
Free Member
 

+1 all that has been said already


 
Posted : 06/02/2020 10:38 pm
Posts: 7995
Full Member
 

Non boost cranks on a boost frame. Had the chainring both inside and outside the spider. Can't really tell much difference, but then I've never really worried about chainline on any bike I've built up.


 
Posted : 07/02/2020 8:07 am