So I am trying to swap bike parts to this Surly KM frame and I have run into an issue with the rear wheel.
I am trying to mount a Bontrager Line Comp 40 TLR Boost 27.5+ rear rim with 148 x 12mm thru-axle
But it doesn’t fit unfortunately. I am a little confused since on Surly official website they show that they have a rim with the same dimensions installed.
https://surlybikes.com/bikes/karate_monkey
It is clear I am missing something fundamental here. Any advice would be greatly appreciated!!
If this wheel doesn’t fit would anyone recommend me to a set that would? Thank you!!!
My apologies for the rookie questions.
by Significant-Role-828
4 Comments
Question: what does the other side look like and is the tire contacting anything that could prevent installation?
I have the same setup(karate monkey with rapid drive 148 hub that is) and it slides in without issue.
Technically the KM uses a “gnot” boost setup which is classified as 12×145. Where it spreads 3mm for boost or clamps 3mm in for non boost thru axle.
Here’s my girl. Currently just a 2 bottle setup, but singlespeed and ready to throw down.
https://preview.redd.it/duydokw565ac1.jpeg?width=1082&format=pjpg&auto=webp&s=e5bb5331321feb9afd775833b080266bc9610bb6
My understanding reading the documentation The ‘Gnot’ drop outs (145mm) are an in between boost (148mm) and normal TA (142mm) – because it’s steel the frame can be flexed or compressed to fit either standard with their provided axle. This is similar to early days of 130mm hubs when frames were made to 128mm to split between old 126 and new 130
my last frame was a KM with “gnot boost” spacing. it started with a 142mm hub and later switched to a 148mm hub. for the wider hub, you need to spread the dropouts apart just a bit. It worked fine for me for a few years. I used a Surly chain tug on the right side to help get the tension just right, then just centered the tire in the frame by hand before tightening that little bolt. IFAIK, that little bolt for the axle is supposed to be torqued to 16Nm, which is more than you will probably feel is safe. I never broke one, so it seems to work.
Are you taking into account the Gnot-Boost spacing? So basically, the frame spacing is more or less 145mm and relies on a little frame flex to accommodate for both 12 x 142 and 12 x 148 (boost) axles.