Cold Setting 4130

mr_eddy

I picked up a Single Speed frame recently during a black Friday sale, I have enough spares etc to make a half decent SS bike. My only issue is the frame rear triangle spacing between the track ends is 120mm but I need it to be 130mm.

I am planning on cold setting the frame using the threaded rod and bolt method but I just want to make sure that its ok to do it on this type of frame.

Forgive my ignorance but cold setting advice on various website states that it can only be done on steel bike frames but does not specify specifics - Is CrMo 4130 a suitable material for cold setting (is it 'proper' steel) and if so is it safe to go 120-130mm without braking anything like the welds etc.

I have a nice set of Shimano RS20 wheels that would work a treat plus a nice SS kit from Onza that would help make up a nice bike. I have a set of carbon drops and so Tektro cross levers and 105 brakes , Throw in scuffed but functional Prolite 46t chainset etc and I reckon I can have a decent SS bike at less than 8kg for less than £200

Advice please.

Ta.

timothyw

I'm sure it's possible, but I think you'd be better off getting a rear wheel with 120mm OLD - given the frame has proper sliding dropouts you're never going to get them quite parallel without a lot of faffing about, and if they're not quite parallel then it'll make it that much harder to get the wheel straight each time you come to adjust the chain tension, then if you do get a proper track wheel are you going to cold set it again?

Plus of course, you're denying yourself the chance to try riding fixed!

V-sprint aka Jim Varnish sells individual track wheels here: http://v-sprint.com/cycling-products/ca ... ck-wheels/

Failing that I'm sure you can get something dirt cheap second hand off LFGSS.

Honestly, I don't think it's worth it. Save the rear wheel for another project.

mr_eddy

I may look at a new wheel, The frame has integrated chain tension screws so surely that would resolve the alignment issue / chain tension ?

Just to clarify then cold setting by an extra 10mm on a 4130 frame is not going to break anything ?

mr_eddy

FYi - I did try fixed once but it was pretty scary ! Also I have a few biggish hills nearby so freewheel is best for me. Thanks for the link I will look into that.

timothyw

If you haven't read this, I suggest you do:
http://www.sheldonbrown.com/frame-spacing.html

Noone is going to come on here and say 'cold space your new frame, I guarantee you it will come to no harm'. There is always an element of risk - you are stretching the bike's frame, and in so doing you are bound to be weakening it's structural integrity at least somewhat. This is also why you won't find many shops willing to perform the procedure for you (and accept the liability).

I'm assuming the frame you have is new and shop bought, in which case you're immediately invalidating the warranty before even riding it?

To me, spacing it to 130mm would be reasonable if you actually needed/planned to run a modern 8-11 speed freehub (and gears) on it, but since you only want to run singlespeed I honestly can't see the point. 120mm track wheels are the current standard and widely available. If you can't use the RS20s elsewhere or down the line, sell/trade them on and get some proper track wheels.

I've never personally cold spaced a frame, but my personal experience which is somewhat related is:
- I rode my benotto beater bike with a 130mm OLD rear wheel for a few months as I had the wheel anyway, and the 126mm wheel it came with was dead. Ultimately, the weld failed where the seat tube met the bottom bracket - something benottos are a bit infamous for. Could be related to the big rear wheel, probably not though.

- My Fuji disc braked commuter has 132.5 mm rear spacing, a halfway house that allows you to run 130mm road wheels or 135mm disc road wheels. This is notable mainly because it is an Aluminium frame, and it's widely known that you can't cold set aluminium - but obviously Fuji feel that there is enough flexibility in it to accommodate both those standards.

mr_eddy

Thanks for the advice , That is a fair point. I have not done the procedure yet so will see. Re the warranty it only comes with a 3 month warranty as it is a old display model (hence the epic discount) so I am not too worried about that.

The Rookie

mr_eddy wrote:

I may look at a new wheel, The frame has integrated chain tension screws so surely that would resolve the alignment issue / chain tension ?

No, as you spread the rear the dropouts will no longer be parallel (they will be further apart at the rear than at the front) will you set it at 130mm at the front or rear of the dropout? Noting you need to be able to remove and refit the wheel roadside in the event of a puncture.