Cold setting
05-14-23 | 08:15 AM
#2
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From: TN
I've done this a few times, after seeking out info online. However, I've never come across this wee factoid that came to mind during my last cold-setting adventure. Seems one can buy an internal expander, to achieve the desired effect ... widen the gap using the adjusting nuts until the gap is greater than desired but springs back to the correct gap. Something like that.
Here is my technique, that can be applied to widening or narrowing the gap. This example deals with widening:
Rear fork width - 126mm
Desired fork width - 130mm
Difference - 4mm
So, I bend one side until the gap is 128mm, taking care not to alter the position of the other side. Then I bend the other side until the gap is 130mm, taking care not to alter the other side.
Result! Gap widened perfectly in line with the frame.
I genuinely have never seen this mathematical method outlined in detail anywhere online. Sometimes, it seems to be inferred as 'obvious', but never explained in words and simple maths.
I hope this will be useful to someone.
Cheers!
Here is my technique, that can be applied to widening or narrowing the gap. This example deals with widening:
Rear fork width - 126mm
Desired fork width - 130mm
Difference - 4mm
So, I bend one side until the gap is 128mm, taking care not to alter the position of the other side. Then I bend the other side until the gap is 130mm, taking care not to alter the other side.
Result! Gap widened perfectly in line with the frame.
I genuinely have never seen this mathematical method outlined in detail anywhere online. Sometimes, it seems to be inferred as 'obvious', but never explained in words and simple maths.
I hope this will be useful to someone.
Cheers!
You might post some pics showing how you isolate one chainstay from the other when using the expander.
05-14-23 | 11:44 AM
#5
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From: Portland, OR
Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder
I still like to do the check with the main diamond. (ie the string test or similar.) Should completely confirm what you are saying but in the real world, often that redundant check finds something that would have slipped under the radar otherwise.
05-14-23 | 11:45 AM
#6
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this is the sheldon browm method more or less
and as a reminder steel frames only
https://www.sheldonbrown.com/frame-spacing.html
and as a reminder steel frames only
https://www.sheldonbrown.com/frame-spacing.html
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Life is too short not to ride the best bike you have, as much as you can.
Life is too short not to ride the best bike you have, as much as you can.
05-14-23 | 12:05 PM
#8
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From: Phoenix, AZ
"I bent & stomped, and it turned out great!
But I wonder what that '753' sticker means?"
(Disclosure: I have cold-set many triangles, with mostly successful results.)
But I wonder what that '753' sticker means?"
(Disclosure: I have cold-set many triangles, with mostly successful results.)
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Richard C. Moeur, PE - Phoenix AZ, USA
https://www.richardcmoeur.com/bikestuf.html
Richard C. Moeur, PE - Phoenix AZ, USA
https://www.richardcmoeur.com/bikestuf.html
05-14-23 | 12:13 PM
#11
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From: San Jose (Willow Glen) Ca
Bikes: Kirk Custom JK Special, 86 De Rosa Pro, '84 Team Miyata,(dura ace old school) 80?? SR Semi-Pro 600 Arabesque
IMHO this is way better that trying the rod and nut approach as between things like dimples for chain ring clearance there is not guaranteed even movement
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Life is too short not to ride the best bike you have, as much as you can.
Life is too short not to ride the best bike you have, as much as you can.
05-14-23 | 03:49 PM
#15
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Bikes: 1984 Gitane TdF, 1983 Colnago Super, 1986 Look Équipe, 1981 Gios Torino SR, 1988 Peugeot Chorus, 1988 Peugeot Biarritz, 1986 Bertin SC37
You don't mention checking the dropouts (fork ends) for being parallel after your cold set.
I once had a used bike that had funky handling. I took it to a competent shop with dropout alignment cup-tools and they straightened the dropouts to parallel.
The handling was transformed! A much better ride was the result.
I'm not knocking anyone's skills here. But anyone who can tie a pair of shoes could follow that string alignment procedure.
It takes top skills to produce a nicely riding bicycle. From now on, I take all my used bike purchases to a professional frame maker for alignment.
I once had a used bike that had funky handling. I took it to a competent shop with dropout alignment cup-tools and they straightened the dropouts to parallel.
The handling was transformed! A much better ride was the result.
I'm not knocking anyone's skills here. But anyone who can tie a pair of shoes could follow that string alignment procedure.
It takes top skills to produce a nicely riding bicycle. From now on, I take all my used bike purchases to a professional frame maker for alignment.
05-14-23 | 04:45 PM
#16
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Of course, steel is springy, so you have to bend it much more than 2 mm to get it to eventually stay 2 mm wider .... per side.
yeah, Sheldon Brown advocated this method decades ago .... and I am quite sure he didn't invent it.
I have had good luck with the threaded rod method, however .... whatever get you where you want to be .....
yeah, Sheldon Brown advocated this method decades ago .... and I am quite sure he didn't invent it.
I have had good luck with the threaded rod method, however .... whatever get you where you want to be .....
05-15-23 | 04:31 PM
#23
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I did it by making an alignment table from an old pool table slate. I epoxied a steel support tp it where a threaded rod could be locked out in the center so either side could be opened (or closed) as required. I got the idea from a frame builder who did this to "cold set" and align finished frames. You could also secure the frame from the HS, BB, or fork, to nudge as required. I think we might still have it, but I haven't seen it in years,
05-15-23 | 04:38 PM
#24
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It doesn't. Most frames will bend fine doing it that way, but some will have one stay "softer" than the other, and it will move first and with less force, and it will be obvious, and yes, gotta check against the rest of the diamond, but again, most times it will be ok after bending (I mean setting), if it started out ok to begin with.
05-15-23 | 05:40 PM
#25
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From: TN