MegaSack DRAW - This year's winner is user - rgwb
We will be in touch
Am I right in thinking that bunging a single ring on the outside ring position of a normal triple will pretty much give me a Boost chainline? (52mm minimum?)
Quick bump for this. Normal triple is about 49/50mm - moving to the other side of the tab mut give another 2.5-3.5mm, right? So around 52/53mm, with 52 being boost standard?
Yeah you are right there. Worth noting though that because of the way frames are designed, you might get away with the middle ring too, if the chainring is small enough.
Yeah - it's for a new frame, has a 6mm offset rear end for clearance, so they have a 52mm minimum - but reusing my old cranks will save me a few quid that can be used for other goodness like 11 speed XT at the back.
Also if you have a frame with a BSA BB, you could move the 2.5mm BB spacer to the non drive side and the chainring in the outer position to get the right chainline.
If you think about it, a triple tab is about 2.5-3mm thick, a NW chainring is 3mm thick, so centre line of the chainring will be 1.5. moving that to the other side of the tab will bring the centre line out by about 5-6mm. Taking the ablve figures it moves the chainline from 49-50mm to 54-55mm. Removing a 2.5mm spacer from the drive side BB will bring that back to 52-53mm or therabouts.
Unles you've a PF BB then it'll be more of a compromise, unless you can space out the spider a bit from the back to the cranks.
Yeah... I'll get a proper crank for it later, will just use the old one temporarily.
honourablegeorge
That new frame with the 6mm offset wouldn't be a Last Bikes fast Forward would it ? either way, whats your plan for re-dishing the rear wheel to compensate for the 6mm offset ?
It is, yes. I had a Specialized Demo a few years back with a similar offset, my LBS redished a wheel for me, took him ten minutes, and I rode DH on it for years after.
Wheels for the last will be new, so will have them built with the offset, but I wouldn't see it as an issue for most wheels, it only makes 0.8mm difference to spoke length
Good stuff, Hopefully I can get my new American classic AM rear redished without any hassle, I must admit I ordered the frame before I read the spec in detail, bit of a stock when I noticed the 6mm offset..
oh well, fingers crossed the frames come on time !
Yeah, February is a long time away, deffo didn't seem this long when I ordered.