lechatnoir Posted January 11, 2019 Share I'm building up an XC-type bike and the frame has boost spacing. Does this mean I need a boost-type crank? And if so, what is that exactly? Link to comment Share on other sites More sharing options...
fanievb Posted January 11, 2019 Share yes you need a boost crank otherwise your chainline will be offhttps://www.oneupcomponents.com/pages/understanding-chainline-for-optimal-1x-conversions-boost-and-non-boost Link to comment Share on other sites More sharing options...
Pulse Posted January 11, 2019 Share There is a ~ 1.6mm difference in chain line. You should be able to run normal crankset, depending on the size chainring you want to use. The chainring may cause clearance issues at the chainstays, but usually is no issue. Edit: There are some offset shainrings available that will negate the need for boost specific crank, and normalise chainline Edited January 11, 2019 by Pulse Mr. G and lechatnoir 2 Link to comment Share on other sites More sharing options...
dirtypot Posted January 11, 2019 Share You don't have to have a boost crank. If you already have a normal crank then use that and you'll be fine. I use a normal crank on my boost frame. No issues. Mr. G, B20PV, lechatnoir and 1 other 4 Link to comment Share on other sites More sharing options...
Captain Fastbastard Mayhem Posted January 11, 2019 Share I'm building up an XC-type bike and the frame has boost spacing. Does this mean I need a boost-type crank? And if so, what is that exactly?Same as a normal crank, except with the chainline offset 3mm further to the outer edge of the bike. But as people have said above, you do not NEED the thing. Existing one will work. Edited January 11, 2019 by Captain Fatbastard Mayhem B20PV and lechatnoir 2 Link to comment Share on other sites More sharing options...
lechatnoir Posted January 11, 2019 Share There is a ~ 1.6mm difference in chain line. You should be able to run normal crankset, depending on the size chainring you want to use. The chainring may cause clearance issues at the chainstays, but usually is no issue. yes you need a boost crank otherwise your chainline will be off https://www.oneupcomponents.com/pages/understanding-chainline-for-optimal-1x-conversions-boost-and-non-boost so, it's a chainring-thing, not the crank itself? so a chainring with the required offset on a regular crank will be OK to get the chain line right? many thanks dirtypot, fanievb, Milkman and 1 other 4 Link to comment Share on other sites More sharing options...
fanievb Posted January 11, 2019 Share so, it's a chainring-thing, not the crank itself? so a chainring with the required offset on a regular crank will be OK to get the chain line right? many thanks yes only a chainring with the correct offset (i made a booboo in my other post) Link to comment Share on other sites More sharing options...
splat Posted January 11, 2019 Share so, it's a chainring-thing, not the crank itself? so a chainring with the required offset on a regular crank will be OK to get the chain line right? many thanks That's the way I understand it.(unless the new BB is some strange width) What crank and ring do you have now? Link to comment Share on other sites More sharing options...
lechatnoir Posted January 11, 2019 Share That's the way I understand it.(unless the new BB is some strange width) What crank and ring do you have now? Scouring the classifieds as I type this... Picking up the frame tomorrow and will get an idea of what's what Link to comment Share on other sites More sharing options...
Grease_Monkey Posted January 11, 2019 Share Cranks are 100% the same. Your chainring will now be 3mm offset instead of 6mm. I would recommend getting the right chainring, don't wanna chew up an expensive cassette unnecessarily.... Captain Fastbastard Mayhem and GrahamS2 2 Link to comment Share on other sites More sharing options...
Li Mu Bai Posted January 11, 2019 Share OMG, dont go buy a new "Boost" crank.You can use your old crank and merely change the chainring to one with a 3mm offset rather than the standard 6mm offset.And save a lot too... Link to comment Share on other sites More sharing options...
Dirt Tracker Posted January 11, 2019 Share I've been running around with a normal crank in a boost frame for the last year and the cassette, chain and rear of the world has kept turning with out a worry. Haven't been throwing away cassettes or sobbing over the endless stream of chains I've had to buy. Pulse and B20PV 2 Link to comment Share on other sites More sharing options...
lechatnoir Posted January 11, 2019 Share OMG, dont go buy a new "Boost" crank.You can use your old crank and merely change the chainring to one with a 3mm offset rather than the standard 6mm offset.And save a lot too... I WAS a little clueless TBH, but nope... not buying a boost crank... more like buying A crank, as I have nothing at present. I see a crank in the ads, so now it's a boost chainring... or at least one with the appropriate offset Pulse 1 Link to comment Share on other sites More sharing options...
Pulse Posted January 11, 2019 Share I've been running around with a normal crank in a boost frame for the last year and the cassette, chain and rear of the world has kept turning with out a worry. Haven't been throwing away cassettes or sobbing over the endless stream of chains I've had to buy.Agree. Unless one is running SS, the chainline changes every time one shifts gear; so chainline is almost never ‘optimal’. BUT running the currecf chainline would minimise wear on the outermost cogs Link to comment Share on other sites More sharing options...
Dirt Tracker Posted January 11, 2019 Share Oh, let's not forget the introduction of the DUB standard. Link to comment Share on other sites More sharing options...
DuncanCT Posted January 11, 2019 Share Here's a really good article explaining a number of different aspects... https://www.wolftoothcomponents.com/pages/boost-chainline-and-chainrings See on non plus bikes the chainstay clearance is one of the most important on modern bikes. Link to comment Share on other sites More sharing options...
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