IMO, as stated above, probably will not be a problem, but the dropouts may need to be re-aligned. I have cold set 2 steel frames, one from 126 to 130, and one from 120 to 130. The latter is a Fuji Ace that I would not have been happy, but not too upset, if something went wrong. Both times I used the same method and homemade spreader as RJ the bike guy, Youtube video. The Fuji, surprisingly, ended up with the dropouts still aligned, the other, Ochsner road with Aelle tubing, needed the dropouts re-aligned. I did that using another RJ video and homemade tool. They did not come out perfect, but close enough for me. If the Ochsner had been messed up from this procedure, that would have bothered me. If the drop outs are not parallel, the odds of the wheel slipping in the dropouts are high, especially when putting a lot of torque into the pedal stroke.
In reality, if being used just on the trainer, not being dismounted, spreading it enough by hand to get properly mounted and left there, I would not bother cold setting it. The only other thing I can add, I am nearing 70, and trying to spread the rear by hand was just too much of a pain. I am not as strong as I once was, and arthritis in my hands makes it challenging to do such things.
In the end, I do not regret cold setting, and would not hesitate to do another frameset. One just has to accept the possibility that it could do real harm, from fixable issues to destroying the frameset. If you can live with that, go for it.
Last edited by delbiker1; 02-23-22 at 04:26 AM.
Reason: add more info