27.5er carbon FS build

[dadgel]

Hi all,

First time posting here. Go easy...

I'm looking to build a XC FS bike. I was after a 27.5 because I'm not the tallest chap in the world and I like the idea of keeping the rotational weight down.

However it seems my frame options are pretty limited, and many frames listed from chinese sellers are really 29". (Eg, from what I can make out an FS27 is the same geometry as an FS29)

So my question is: do I need to find a specific 27.5 frame, or will everything work out well if I pop smaller wheels on one of these frames?

I want to keep the weight of the frame down to under 2kg and I'm currently considering an M06, FS27 and FM936. The latter seems to be popular on here, although it seems to be coming up about $300 more expensive at the mo.

[emu26]

If you are going to use a 29er frame keep a close eye on BB drop. Many of the 29er frames have BB drop over 35mm and I think this will lead to pedal strike when you drop to 'Tweener wheels.

Good luck, I'm also looking but I want to go 27.5 x 2.8 - 3.0.  It's like looking for a needle in a haystack.

[ChinaCruz]

You might notice that the frames are advertised as 27.5+/29er. There are some things that you can do to convert to 27 wheels - bigger fork, use 2.6" tires, use offset bushings in the shock, use shorter cranks. I'm using 170mm cranks (from 175mm), one offset bushing, 2.6 tires, and 130mm fork on a 29er spec'd for a 100mm fork. Just pay attention to the axle to crown length.

[jabbajaw99]

You might notice that the frames are advertised as 27.5+/29er. There are some things that you can do to convert to 27 wheels - bigger fork, use 2.6" tires, use offset bushings in the shock, use shorter cranks. I'm using 170mm cranks (from 175mm), one offset bushing, 2.6 tires, and 130mm fork on a 29er spec'd for a 100mm fork. Just pay attention to the axle to crown length.

I'm a bit confused about how offset bushing help. It is my understanding they lower the BB. I figure you want to raise the BB when using smaller wheels. Here is my reference: https://www.offsetbushings.com/pages/how-they-work

[StefanB]

Hmmm, can the offset bushing be used the other way around, to raise the BB instead of lowering it?

That could be usefull when building a bike with 27.5" wheels on a 29" frame.