making non boost crank compatible with boost?

[serviceguy]

Shimano's own instructions dont show the same amount of spacers on each side...
View attachment 108113

That has nothing to do with boost, is just the way you adapt different BB shell width to match the correct width of the standard crank. The 5mm difference between the 68mm and 73mm BB shell is equally split on both sides.

Boost is dead. Super Boost is the now!!

Anyway, there's no point to this conversation, what @jimvreeland said!

 

[Patrick]

If they made the crank arms and chain stays thinner, they could make super mega boost.

who are they? certainly not the peasants.

 

[jShort]

Boost is dead. Super Boost is the now!!

Ironically, super boost has been around forever in DH.

 

[stb222]

That has nothing to do with boost, is just the way you adapt different BB shell width to match the correct width of the standard crank. The 5mm difference between the 68mm and 73mm BB shell is equally split on both sides.



Anyway, there's no point to this conversation, what @jimvreeland said!

lol, boost shimano has a wider spindle, so just need more spacers. I have 500 hours on it with uneven spacers

 

[jShort]

While we're here, would an ultegra arm fit on a Shimano xt crank? @jimvreeland or @stb222

 

[Steve Vai]

While we're here, would an ultegra arm fit on a Shimano xt crank? @jimvreeland or @stb222

Yes. But it won't clear your frame, the offset is way different.

 

[jShort]

Yes. But it won't clear your frame, the offset is way different.

Even on a hardtail?

 

[Steve Vai]

Even on a hardtail?

It'd have to be an older school 29er for the stays to be narrow enough. The MTB arm has a deeper curve to clear the stays, where the Ultegra goes out more gradual.

 

[serviceguy]

lol, boost shimano has a wider spindle, so just need more spacers. I have 500 hours on it with uneven spacers

Uhm, I was under the impression they had a flatter spider for boost cranks. I must have been wrong, what would I know, I have super boost plus.

 

[stb222]

Uhm, I was under the impression they had a flatter spider for boost cranks. I must have been wrong, what would I know, I have super boost plus.

Nope, the difference is in the spindle lengths, hence where there is only one model chainring for each level (SLX/XT/XTR). You may see different offsets fro after market manufactures that are designed for shimano's 12 speed chains.

 

[grilledcheeseking]

super mega boost

*Mega-Super Boost®

 

[serviceguy]

FC-M7000-11-1 (standard) and FC-M7000-11-B1 (boost), same Q-Factor, same chainring (notice the boost has less range, no 34T) , different chainline. I guess the 3mm are factored in the crank/spider only. Same goes for XT.

 

[stb222]

View attachment 108235

FC-M7000-11-1 (standard) and FC-M7000-11-B1 (boost), same Q-Factor, same chainring (notice the boost has less range, no 34T) , different chainline. I guess the 3mm are factored in the crank/spider only. Same goes for XT.

Regardless, you can still has a spacer, to make this up.

 

[TJYeti]

...

 

[Santapez]

Shimano SLX 170mm cranksets have been impossible to get. REI ended up with stock and by that time I forgot to check to make sure it was boost. It wasn't...

Before I put them on I did a quick googling of how much the crankset will not work on my boost bike...this thread was at the top.

I can say no issues in the parking lot test. If anything it does seem to work slightly better in the larger gears. If I had some spacers laying around I'd probably try to push it out a mm or a few mm. Only ones I have are the regular ~3mm spacers and didn't want to mess with BB.

Seems to be A-OK.