Argos fitted new 853 chainstays to my Salsa then didn’t give me enough tyre clearance. So I took it back (only after I’d painted it and built it) and they’ve compressed rather than crimped the stays which is ok, but I think they could have done more. But I haven’t the energy or inclination to argue the point, so I was wondering if it’s possible to do myself.

Apparently 853 needs heating up to bend it. But the question is, how much? I can’t imagine they got the tube red hot because he only stripped about 10cm of paint – if the middle was red hot he’d have bubbled the paint over a greater area surely?

But the internet suggests hot working needs to be done at 60% of melting point which would have had it glowing red hot. So either he’s got some fancy tool that locally heats it and compresses at the same time, or it doesn’t need to be that hot.

Any experience on the forum?

My very loose understanding is that the 853 refers to alloys in the steel alloy ( iron and carbon) that change the eutectic point of the molten metal weld to encourage a pearlite microstructure and hence a stronger weld- well a higher yield point than the surrounding steel.

I would warm up with a paint stripper and use a big vice. But it’s not my newly painted frame and I am no frame builder, just a Muppet.

Tightly wrap a cold wet rag round the tube at either end of the heated/paint free zone then cherry red hot with a brazing/oxy acetylene torch would be my approach.

853 is a heat-treated tube. It’s actually exactly the same composition as a 631 tube. The number doesn’t have anything to do with the composition.  Once the 631 tube is drawn and shaped, some get sent out for heat-treatment (not done in house). When those 631 tubes comeback from treatment they’re now 853. I *think* the 853 originally came from one of the temps used at the heat-treat stage.

FWIW, to answer your original question, adding heat to the tube in order to further process/shape it, isn’t really a good idea.  You want to do that stuff cold.

I didn’t think they made 853 chainstays but I may be mistaken.

2019 Reynolds catalog lists five standard 853 chainstays.

I have dimpled chain stays on a few frames, including 853 stays, for tyre, disc and chainring clearance and have always done it cold. Both before and after paint.

A pair of mole grips with a few suitable sized bits of curved wood do the job well enough, just do it slowly and support the back of the tube carefully.

FWIW, to answer your original question, adding heat to the tube in order to further process/shape it, isn’t really a good idea. You want to do that stuff cold.

Argos heated it up. They just didn’t go far enough IMO, I think they aren’t overly bothered about getting it how I want. But they said it needed to be done hot. Then again, he said he could only form it and not actually dimple/crimp it because he didn’t have the equipment. So maybe that’s why he heated it?

I have dimpled chain stays on a few frames, including 853 stays, for tyre, disc and chainring clearance and have always done it cold.

This is good to know. What makes you confident it’s ok? Just experience?

This is good to know. What makes you confident it’s ok? Just experience?

Just experience TBH. I dimpled a chainstay on a CX frame post painting (because I foolishly didn’t check clearance for a big enough chainring when I built it), I’ve been racing on it for three seasons now and it seen more than 1000km of race / warm up / practice / training so it hasn’t had a gentle life but is still going strong. Similar story with dimpling for disc clearence on a subsequent frame, same lack of issue.

Maybe I have been lucky that I didn’t need much extra clearance so was only adding 2ish mm dimple but tbh if I had a steel frame that didn’t have enough clearance I’d try to cold work it.

“A pair of mole grips”

I’m pathetic. But that made me smile

Well cold working seems to be a legit thing, lots of info about doing it both professional and amateur. I guess I can but try, if it’s too hard it’s too hard. I wonder if it’s worth annealing it after?

EDIT I found this:

Reynolds 853 Technical Advice
Manipulation

Reynolds 853 is a high strength material having limited manipulation capacity in the as-supplied form. Any ovaling/flattening or cranking operations that involve significant amounts of material deformation should not be undertaken. Reynolds are able to carry out these operations prior to heat treatment if required. Minor manipulation, i.e. setting or bending to fit can be carried out in the as-supplied heat treated condition.

Do not attempt to undertake severe manipulation of tube section in the as-supplied heat treated condition.

This suggests it shouldn’t be done at all, never mind hot or cold!