I’m just trying to work out if i can fit Disk brakes on my none disk braked frame.

The reason for this is multiple AND not just because i want the newest and bestest must have thing which is disk right here right now.

I have a YETI ARC-X CX Bike, some on here may be lucky enough to have one, they are a great ride and most importantly look good. So i’m not in a hurry to get rid although selling these second hand is quite easy.

The main reason i want to change to run disk is that i want to run 29er wheels and be tubeless. I’d like a wider rim hence the 29er in STANS Iron Cross. The only one available for Rim is the ALPHA 340 or the newer stronger 400.

Front end isnt a problem as i’ll just swap over forks for some with mouthing points which leaves me with the back end, It must be do-able, a few lugs and a bit of paint.

What do you think.

And yes i know should i should probably flog it and buy one with Disks on but i like it,

I had some disc mounts welded to an early GT I-Drive without any problems apart from having to go up a rotor size due to where the mount needed to be fixed(IS mounting 160mm rotor on 140mm caliper).

Many welders aren’t keen on welding mounts to already heat treated alloy frames as it can weaken the metals structure.

I know someone who did this with their factory Ritchey frame many years ago – off to Utah, first descent pulls lever, snapped seatstay, broken collarbone and next plane home! Frames for discs have reinforced chain/seatstays to take the additional stresses – welding bosses onto the frame can make it weaker if not heat treated correctly. Simply best to get a frame designed for the job.

If you attach a disc to the seat/chainstay you may cause premature failure. On a rim brake frame those parts were not designed to take the forces of a disc brake. You might get away with it. You might not.

Look at CX frames and plenty have a bridge around the disc brake to strengthen it, something you could consider.
To be hones by the time you’ve faffed around welded bits and painted it I would have thought you’d be better off selling it and buying another. There are plenty of nice looking/riding CX bikes out there.

Isn’t the rear spacing 130mm?

Steel frame: Yes, no problem, I do it all the time – with a brace from seatstay to chainstay to take the force.

Aluminium frame: No chance. Can’t heat treat the frame afterwards.

It’s the forks that I’d be more concerned about….

He did say he was going to get replacement disc forks – but yes, retrofitting a disc mount to forks is something to be careful with. Can’t run a brace to the down tube to keep it rigid 😉

It’s the forks that I’d be more concerned about….

You can get new forks (and spray them to match if you’re messing with the frame anyway), frame needs work, though.

[edit: beaten to it by bencooper]

Here’s mine. Chris Dekerf/ Chas Roberts/ Dave Yates collabo.

A2Z disc brake adaptor on rear new forks on front – no welding necessary.