I am looking at bikes to build into a single speed cross bike.

I want some kind of rack and fender compatability, disc ready, canti bosses, at least 35c tyres with possibility for gears (as it may be used as a light tourer and commuter in future versions). I have a cross bike that has cantis and is 130 spacing at the rear and as I have 3 rear wheels for it that isnt something I want to let go but if I do go to a disc cross bike or a 29er I want to be able to use the wheels in it.

Current options are the cotic road rat (which looks alright), Soma Double cross DC (which is impossible to source and is a little pricey), both of which have 132.5 spacing and steel frames.

Now I am considering the Cotic X (same tubing as the road rat) as it also ticks all the boxes but has 135 spacing, should I have it cold set (it is a heat treated frame) to 130 or just use a mtb skewer? I talked to cotic and Cy wasnt the one to answer but, they said “its probably fine, but may crack the stays”.

What to do? Road rat the shit out of it? Cold set? MTB skewer?

Funnily enough, Cotic build the Roadrat with a 132.5 rear end, so youc an use either size as desired. A couple of mm of washers?

Get some 10-14mm ali bmx spacers they are 2.5mm thick. File them down to fit your dropouts. Sorted, this fixed my Ali framed sscx as that would defo snap.

with the spacers would the axle not be sitting in the frame though? My kind of riding has been called ‘unsympathetic’ by some due to my IDGAF attitude towards what I am riding on at a variety of speeds. I would rather not be snapping axles on the hubs, the QR skewers (as far as I am aware so correct me if I am wrong) only pull the frame onto the hub but the hub itself sits into the frame.

TL;DR would the spacers not then stress the hub?

I’ve got a 120mm rear hub that I spaced out to use in a Roadrat frame.
Ran it fixed for a few months and it worked fine.

My Cotic x is sodding tight for 135mm so maybe that’s a bit under as well. Having said that its only gas pipe so just drag it in.
Cold setting is a posh word for bending the bugger.

Ran my On one TiX for ages pulled in to 130mm. First owner did too.
Rear disc mount was a bit squiff, but changed to cantos anyhoo.

The bmx spacers have an external extrusion that go into the dropouts. If its strong enough for bmx it’s strong enough for Sscx!

These are the ones I use