Spreading rear dropouts.

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hoogerbooger
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Re: Spreading rear dropouts.

Post by hoogerbooger »

Thanks for the question and the answers.

I used the threaded rod method on an old Bob Jackson 531 mixte for the missus and it worked very well RE alignment. But I recently realised (!!!) that I've been happily riding my Raleigh Randonneur with 8 speed 130mm hub in the 126mm drop outs. So clever am I, I only realised this when I was trying to work out why the right rear stay was slightly further away from the rim than the left.....on a perfectly centred rim. I have concluded the chainstay dimple must be the main factor, but perhaps also un-parallel drop-outs. I also therefore concluded that the threaded rod method would lead to more movement on the RHS.

Having failed to find a proper frame builder in any sensible travel distance, I will 'man-up & follow the above one side at a time advice......very nervously.....as I care about this frame.
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Mick F
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Re: Spreading rear dropouts.

Post by Mick F »

One way, is to use the "Foot in the Triangle and Pull the Other One" method.
When I did the Eleswick, the threaded bar idea didn't work linearly and accurately, so I resorted to brute force to get the wheel centralised a bit better.
Mick F. Cornwall
Vorpal
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Re: Spreading rear dropouts.

Post by Vorpal »

There are some previous threads on this or similar topics...

viewtopic.php?f=5&t=44455
viewtopic.php?f=5&t=71013
viewtopic.php?f=1&t=139746

Good luck 8)
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Vetus Ossa
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Re: Spreading rear dropouts.

Post by Vetus Ossa »

Still stripping the bike down, everything is tight but I will prevail.
Actually looking forward to spreading the dropouts, I like a challenge. The tracking is good at the moment, just the wrong gap.
Really wish I had a fixed vice, mine is fitted to my workmate. It would be so much easier if I could clamp the bottom bracket in the jaws and give the seat stays a tug like the guy in the video.
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cyclop
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Re: Spreading rear dropouts.

Post by cyclop »

I repeat the previous advice,don,t do this to 753.I bought a resprayed 753 bike many years ago from "Cycling Weekly"which had been spread.Having ridden it for a month or two,I removed back wheel for a good clean and ,to my horror,found two cracks on the inner aspect of chainstays,just before the cross brace/mudguard fixing!!Buyer beware!
I,ve used the Sheldon brown method of spreading stays twice on my two steel frames,no problem.Surprising amount of force needed ,keep measuring as 5mm per side isn,t much.
gxaustin
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Re: Spreading rear dropouts.

Post by gxaustin »

I've used the Sheldon method on a couple of bikes - checking with string, as described by Colin 531.
I used the threaded rod method on a mixte for my wife. I spread the front forks and rears without problem and used this method because the mixte has a very stiff rear "triangle". Front forks are very stiff too. The dimple on the drive side chain stay didn't cause a problem, luckily. I then used the big adjustable spanner method to true up the drop outs, and filed them out to accept QRs.
I fitted 700c wheels in place of the 27" using long reach brakes while I was at it.
fastpedaller
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Re: Spreading rear dropouts.

Post by fastpedaller »

I wonder (irrespective of what steel tubing) whether it's prudent to restrict the bending to the part of the tubing behind the chainstay bridge?
an aluminium U maybe held by a steel G clamp could be sufficient to support it. If the cost is low I'd be tempted to rely on an experienced frame builder to do it - If they have 30 + years of metal manipulation they are more likely to do it well.
mig
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Re: Spreading rear dropouts.

Post by mig »

i had the OLN of some dropouts spread by a frame builder from 126 to 130 a few years ago.

it worked okay but he did mention that the spec of the dropout itself was 'imperial' and hence struggled to accept a 'metric' wheel easily.

at the time i thought that he meant the vertical 'height' of the dropout spacing was a tad smaller.
Norman H
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Re: Spreading rear dropouts.

Post by Norman H »

mig wrote: 8 Dec 2021, 2:09pm i had the OLN of some dropouts spread by a frame builder from 126 to 130 a few years ago.

it worked okay but he did mention that the spec of the dropout itself was 'imperial' and hence struggled to accept a 'metric' wheel easily.

at the time i thought that he meant the vertical 'height' of the dropout spacing was a tad smaller.
He probably meant that the dropouts were for a 3/8” rather than a 10mm axle. Easily corrected with careful use of a file.
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Vetus Ossa
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Re: Spreading rear dropouts.

Post by Vetus Ossa »

I had the necessary bits arrive today and though pushed for time had a quick go at opening out the dropouts. It is currently spaced at 114mm so wound out the nuts on the threaded bar to 140mm. When I slacked them off it went back to about where it was before. Obviously I need to go a lot further than 140mm , but how far, it’s a bit scary isn’t it.
Btw it isn’t a 753 frame, not sure how that got into the conversation, I know that won’t budge having had one.
Mine is just 531.
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David9694
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Re: Spreading rear dropouts.

Post by David9694 »

I have a butchers block in my garage and I trap a dropout and a few inches of chain/seat stay in the open draw and bear down on the head tube. The amount of force needed I have found to be quite variable, so you’re taking it out measuring for any change and turning over frequently.

You should then check the dropouts are aligned and straight - I have a cheap version of the tool for this, but it’s a strange set-up that I’m not sure I’ve fully understood. I’m a bad cyclist, though, I don’t check for tracking and I don’t understand measuring chainline.

When you get a puncture fairy visit, you’ll be glad the wheel goes in and out easily.
Spa Audax Ti Ultegra; Genesis Equilibrium 853; Raleigh Record Ace 1983; “Raleigh Competition”, “Raleigh Gran Sport 1982”; “Allegro Special”, Bob Jackson tourer, Ridley alu step-through with Swytch front wheel; gravel bike from an MB Dronfield 531 frame.
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Vetus Ossa
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Re: Spreading rear dropouts.

Post by Vetus Ossa »

David9694 wrote: 11 Dec 2021, 3:19pm I have a butchers block in my garage and I trap a dropout and a few inches of chain/seat stay in the open draw and bear down on the head tube. The amount of force needed I have found to be quite variable, so you’re taking it out measuring for any change and turning over frequently.

You should then check the dropouts are aligned and straight - I have a cheap version of the tool for this, but it’s a strange set-up that I’m not sure I’ve fully understood. I’m a bad cyclist, though, I don’t check for tracking and I don’t understand measuring chainline.

When you get a puncture fairy visit, you’ll be glad the wheel goes in and out easily.
I have a big adjustable that I plan to square up the dropouts with, I think that won’t be too much of a problem.
Totally agree about the desirability of having a wheel drop in and out easily.
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Vetus Ossa
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Re: Spreading rear dropouts.

Post by Vetus Ossa »

This is proving to be more difficult than I thought it would be, grrr.
I did manage to get the right spacing (126mm) using threaded bar and nuts method,but the wheel sat towards the none drive side in the dropouts.
So thought I would try the SheldonBrown way.
I did manage to bend the left hand seat stay back in quite easily but the drive side one is proving very difficult, so difficult I broke the wood I was using.
As I still need to find another 6mm I guess I will have to find a bigger bit of wood :(
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Jamesh
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Re: Spreading rear dropouts.

Post by Jamesh »

Would it work warming the frame?

Doing it in a cold garage imho is asking for cracks. Putting it above the woodburner would be me preferred preparation. Remember the liberty ships....

Also wouldn't frames about 531 be tougher more likely to crack?
Seen plenty of 953 and titanium frames with cracks.

Cheers James
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Re: Spreading rear dropouts.

Post by Vorpal »

Jamesh wrote: 22 Dec 2021, 2:19pm Would it work warming the frame?

Doing it in a cold garage imho is asking for cracks. Putting it above the woodburner would be me preferred preparation. Remember the liberty ships....
Warming it to much hotter than what you'd get above the woodburner would only make a slight difference in the forces required, and I don't think it would make any difference whatsoever in the likelihood of a crack forming.
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