Bending steel frames?

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declan1
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Bending steel frames?

Postby declan1 » Sun Dec 09, 2012 17:48 pm

Hello all,

My current 'best-bike' (see BSA in my sig) has 7-speed wheels, and obviously in the near future they'll need replacing (I have no idea what condition the rim is in). Presuming, since they're 7-speed, the axle width is 126mm (correct me if wrong). Current wheels are 130mm.

I know you can bend the rear triangle to accommodate the new wheel, but I need to bend it with a fair bit of force just to get the current wheels in, so any more and it'll probably snap or something!

Any advice on this issue?

Road - Dolan Preffisio
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onbike 1939
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Re: Bending steel frames?

Postby onbike 1939 » Sun Dec 09, 2012 18:59 pm

The rear triangle can be widened to fit a wider hub. I can recommend this method:


http://sheldonbrown.com/frame-spacing.html

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Rolf F
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Re: Bending steel frames?

Postby Rolf F » Sun Dec 09, 2012 19:15 pm

Or just get the existing hubs built into new rims. Or replacement period wheels. Not hard to find.
Faster than a tent.......

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declan1
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Re: Bending steel frames?

Postby declan1 » Sun Dec 09, 2012 19:23 pm

Rolf F wrote:Or just get the existing hubs built into new rims. Or replacement period wheels. Not hard to find.


My LBS said they could build me a new set, but I would much prefer new wheels though, mainly because I may upgrade the groupset to a newer one in the future, needing a newer hub.

I'm just worried that the triangle will snap or be seriously weakened with all that bending! Maybe I'll get the LBS to do it - they'll probably know if it's too much for the frame...

Road - Dolan Preffisio
MTB - On-One Inbred

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declan1
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Re: Bending steel frames?

Postby declan1 » Sun Dec 09, 2012 19:59 pm

Ok, just measured the rear drop-outs - 120mm inside-to-inside...

That means it was probably an old 5-speed...

So, I presume taking it to 130mm is out of the question?

Road - Dolan Preffisio
MTB - On-One Inbred

I have no idea what's going on here.

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Rolf F
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Re: Bending steel frames?

Postby Rolf F » Sun Dec 09, 2012 20:38 pm

declan1 wrote:
Rolf F wrote:Or just get the existing hubs built into new rims. Or replacement period wheels. Not hard to find.


My LBS said they could build me a new set, but I would much prefer new wheels though, mainly because I may upgrade the groupset to a newer one in the future, needing a newer hub.


A new groupset is a new groupset but that doesn't mean it is an upgrade. Not convinced there is anything on the market today that is as nicely made as the Suntour groupset on my Raleigh. Probably weighs less than anything current as well. It's a nice bike - don't spoil it :wink:
Faster than a tent.......

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declan1
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Re: Bending steel frames?

Postby declan1 » Sun Dec 09, 2012 20:58 pm

Rolf F wrote:
declan1 wrote:
Rolf F wrote:Or just get the existing hubs built into new rims. Or replacement period wheels. Not hard to find.


My LBS said they could build me a new set, but I would much prefer new wheels though, mainly because I may upgrade the groupset to a newer one in the future, needing a newer hub.


A new groupset is a new groupset but that doesn't mean it is an upgrade. Not convinced there is anything on the market today that is as nicely made as the Suntour groupset on my Raleigh. Probably weighs less than anything current as well. It's a nice bike - don't spoil it :wink:


Yeah. I completely agree with you. I don't want to ruin it - I love the current Shimano 600 Ultegra, but, as with everything else on the bike, I have no idea how many miles it's had to put up with.

Road - Dolan Preffisio
MTB - On-One Inbred

I have no idea what's going on here.

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Rolf F
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Re: Bending steel frames?

Postby Rolf F » Mon Dec 10, 2012 10:37 am

You can always stock up with parts as they turn up if you are worried. Ebay and Retrobike forums have all sorts of stuff all the time often in unused condition. But unless you are doing 1000s of miles in all sorts of conditions, I'm not sure it is much worth worrying about. Sometimes I think I ought to get some back up spares for my Raleigh Record Ace but tbh it only goes out a couple of hundred miles a year so it will be decades before anything wears out! It did come with some fairly crap steel wheels but it wasn't hard to source some genuine Record Ace alloys (though ultimately they weren't the best purchase - non stainless spokes and an irregularity in the rear rim that can be felt on braking - not that I brake on the back much anyway). I'll be dead before I need a new block.......
Faster than a tent.......

Bordersroadie
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Re: Bending steel frames?

Postby Bordersroadie » Mon Dec 10, 2012 11:40 am

declan1 wrote:Ok, just measured the rear drop-outs - 120mm inside-to-inside...

That means it was probably an old 5-speed...

So, I presume taking it to 130mm is out of the question?


Not really. My 531 frame went from 120 to 130. Just take the precaution before you coldset to clamp the bridges with G-cramps plus wooden blocks shaped to the seat and chain stay profiles. Easy with the right size drill and a saw.

Note your dropouts will definitely need realigning if you go 10mm wider.

thecycleclinic
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Re: Bending steel frames?

Postby thecycleclinic » Mon Dec 10, 2012 23:12 pm

I hadf this issue with a customers bike that was in for restoration. He wanted new wheels but it was a120mm frame. I did no want to space the rear frame to 130mm so built the wheel with 126mm hubs (yes they are still avialble new from the right suppliers) and cut the axle to 120mm. I dished the wheel appropriatley and the 5 speed frewwhel did fit and everything cleared the stays just.

I would take a 120mm frame to 126mm but any wider will require alot more care and there is more risk which is why for a customers bike I did not take that risk. Also NOs shimano 126mm 7 speed hubs are still available. Everything is doable depending on what you want to do.
http://www.thecycleclinic.co.uk -wheel building and other stuff.


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