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cold setting

Posted: 14 Dec 2015, 10:46pm
by cyclop
Has anyone cold set a steel frame.Looks easy enough according to sheldon brown.I,m wanting to go from 5 to 7speed freewheel i.e.120mm to 126mm and don,t want to simply spring the rear triangle.Any experience of doing this welcome.

Re: cold setting

Posted: 14 Dec 2015, 11:34pm
by phil parker
Yes, I have, numerous times, mainly on 531 frames, also 525, 520 & 501 - I have never had a problem. Some frames and steel material will not cold set (753, I think) so please consider?

I do have a set of drop-out alignment tools, but they are not really necessary, just a confidence booster as well as confirmation if other problems arise. I used to use a car scissor jack and you do have to extend up to 2" beyond your final measurement before the chain stays spring back to their new position, but, needless to say, you must do this in smaller increments first and determine the spring back final measurement. There is also a simple method to ensure triangular symmetry if required? (I can advise)

Good luck!

Re: cold setting

Posted: 15 Dec 2015, 5:52am
by cyclop
Thanks for the confidence booster.The frame is a "Maurizio"-Fausto Coppi model,possibly 50,s,with no indication of tube type.By triangular symettry,do you mean the dropouts being equidistant from the centre line after setting and,if so,is the string method shown by sheldon brown good enough?

Re: cold setting

Posted: 15 Dec 2015, 7:31am
by [XAP]Bob
Yes, then check the dropouts - they should be parallel as well, again Sheldon is quite clear :)

Re: cold setting

Posted: 15 Dec 2015, 8:04am
by phil parker
I've not read Sheldon for a while,but I've no doubt his method will be good enough!

I use a known straight edge (which can even be a new broom handle, but I use a long spirit level that I have) and place against the head stock and the seat tube at such an angle that it passes the inside of the drop out - and measure the distance between dropout and straight edge. Then place the straight edge on the other side of head stock and seat tube and measure the distance to the dropout etc.

As mentioned above, the dropouts should be parallel, which I do with alignment tools, but can probably be done fairly accurately be eye.

Re: cold setting

Posted: 15 Dec 2015, 8:12am
by 531colin
First job is to check the frame is straight now.....
I prefer to pull out one dropout at a time, if you put a jack between the dropouts there is no guarantee they will come out evenly, particularly if the right chainstay has a dent to clear the chainwheel.
Lay the frame on the floor with supports (eg fencepost) under the seat tube and head tube, stand on the seat tube and pull the first dropout until you have 123mm, then pull the other one to 126mm.....or use Sheldon's lever method.
Then check the dropout alignment, and re-check the frame alignment.
On the other hand, springing a steel frame a small amount doesn't seem to be a problem anyway.

Re: cold setting

Posted: 15 Dec 2015, 8:15am
by Mick F
I didn't like Sheldon's idea, so I did it with my own method.
It worked, I can assure you.

Strip the bike down to the bare frame and lie it down on the floor. Carpeted floor is best.
Put one foot on the lower chainstay right up against the chainstay bridge and the other foot on the dropout.
Grasp the other dropout with both hands, and tug hard. You'll feel it "give".
Turn the frame over, and repeat on the other side.

Obviously, don't tug too hard, just enough to overcome the springiness of the rear triangle.
After each tug, do some measuring. Get the rear gap correct, then fit the rear wheel and check the alignment. If it's off to one side, re-adjust as necessary.

I did this with Barbarella. She originally had a 5sp freewheel, and I opened her up to an 8sp Nexus. Alignment is perfect.

Re: cold setting

Posted: 15 Dec 2015, 9:14am
by Brucey
a small amount of frame springing isn't usually a big deal but I've seen enough sprung frames break to know that it almost certainly increases the chances of breakage. So if you are going to fit a wider wheel, its best if you know it is a permanent change and you cold set the frame to match it.

If you are going to cold set it I too favour some method whereby you do one side at a time (as per Colin or Mick); most frames don't 'give' each side evenly, not least because there is often a big dink in the RH chainstay. Note that even a small dropout misalignment can hasten the failure of the axle or the dropout itself, so check this carefully and reset accordingly.

Note also that if the frameset is CrMo and it has been brazed in a bit of a rush the chainstays could be lacking in ductility. On any older frame there is a chance of corrosion inside the frame too. Thus cold setting an older frame in unknown tubing is never entirely risk-free.

BTW although I've cold set many frames wider (and at one time would have done this to your frame without a second thought) I have since begun to question this practice; not because 'it doesn't work' per se (it usually does) but more because the several of the reasons for cold-setting such framesets are now less relevant, for example;

- 'to give the machine more gears' ; well you can get the range some other way, and unless you are riding flat out in a group, larger gaps between the gears are not as important as most people suppose.
- 'to allow the use of contemporary parts'; -well I don't think it matters much between 5s 6s or 7s, there's not that much choice in decent quality new stuff...

On the other hand there are good reasons for leaving it alone, eg that if you are riding a frameset from the 50s or 60s and you can do, you may as well build it up with period correct components where possible; in another ten or twenty years time the use of such machines (when they were new) may well have fallen out of living memory and such a machine will be seen more as an antique.

If you want to have your vintage cake and eat it, there are a few options for 'more gears' on a non-period correct rear wheel around 120mm. Obviously this doesn't stop you from using a period correct 120mm rear wheel when the fancy takes you.

- a compact 6s freewheel. These were quite common at one time; Maillard, Atom, Sun Tour etc all made them and you can still find them on e-bay, at cycle jumbles etc. You can sometimes make your own by taking a 7s freewheel and (if the top two sprockets are threaded and overhang a short body) you can simply delete the smallest. If this means (say) losing a 13T sprocket, I'd argue that you are not missing that much if you don't have it.

- freehub options. The very first shimano freehubs were available in 120mm 5s versions. If you can get a hub like that, you can (by modifying one spline on the sprockets) fit sprockets from any modern cassette onto the freehub body (except in the top position which uses a threaded sprocket to retain the others). Using this approach you can build (say) a 7-from-10 cassette hub that is about 120mm width.

In point of fact for the latter approach, all you need is the 5s freehub body itself; although not originally bolt-secured, it turns out that these 5s freehub bodies can usually be secured to later shimano hubshells using the bolt-securing approach. The bore dimensions and drive spline interface are common between early bolt-secured freehub bodies and the previous non-bolt secured freehubs.

- Because there are many people wanting to preserve the originality of older frames and yet gain the advantage of modern technology, you can now buy cassette hubs in narrower OLNs for older frames. eg compass bicycles



Re: cold setting

Posted: 15 Dec 2015, 4:50pm
by cyclop
Some good info here,thank you.

Re: cold setting

Posted: 15 Dec 2015, 10:46pm
by Ross K
Just to add another reassuring tale:

My from-new 531c frame of 1986 was 120mm but had a 126mm wheel crammed in for many years, without cold setting. It measured 122mm when the wheel was out, and the wheel, when in, sprung it to 126mm.

Four years ago I cold set it a la Sheldon to 130mm and used a big adjustable spanner to make the dropouts parallel again

Since then I've done a couple of thousand miles a year on it, with an 8 speed cassette on a modern hand built and friction shifters, with no problems whatsoever.

Re: cold setting

Posted: 16 Dec 2015, 9:59pm
I've done the Sheldon method. It worked fine, although the process is a little unnerving. I would only add (if Sheldon didn't mention) that the drive side chain stay will bend very easily compared to the NDS if it has an indent for the chainrings.

Re: cold setting

Posted: 16 Dec 2015, 10:19pm
by mig
daft question. has a frame been cold set successfully to make the dropouts narrower?

Re: cold setting

Posted: 17 Dec 2015, 12:13am
by Brucey
yup, its pretty much the same thing in reverse. The only thing is that the seat stays can end up looking a bit weird.

If they bulge inwards slightly at the bridge (because the frame has been spread), that usually goes unnoticed or at least doesn't look too peculiar, but if they bulge outwards at the bridge as a result of cold setting the other way, that looks a bit odd to me.


Re: cold setting

Posted: 17 Dec 2015, 6:30pm
by hubgearfreak
sheldon's method worked fine for me too. i went narrower