Dropout Repairs - Old Fashioned Engineering...
Dropout Repairs - Old Fashioned Engineering...
I have a plastic bike with aluminium dropouts. Over the years, the front of the driveside and the rear of the non drive side have worn a bit so the wheel can sit a bit squiffy within the chain stays. Even with the QR's well tightened, the wheel can 'pull' over under the immense load of my Amazonian thighs...
I wondering about a bit of remedial work by a proper bicycle engineering company (rather than a shifter of Taiwan derived boxes...). I'm thinking of some sort of machined adapter or weld plus machining. I'd want to minimise damage to the carbon and paint so I may be asking too much.
Any experiences in fixing this and/or recommendations for pukka cycle engineering companies please? The grubbier and oilier the better as these tend to be a better bet.
I wondering about a bit of remedial work by a proper bicycle engineering company (rather than a shifter of Taiwan derived boxes...). I'm thinking of some sort of machined adapter or weld plus machining. I'd want to minimise damage to the carbon and paint so I may be asking too much.
Any experiences in fixing this and/or recommendations for pukka cycle engineering companies please? The grubbier and oilier the better as these tend to be a better bet.
Last edited by boblo on 8 May 2021, 9:24am, edited 3 times in total.
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Re: Dropout Repairs - Old Fashioned Engineering...
I'd suggest that the ideal 'fix' would be to machine the dropout slightly larger, and then 'face' it with steel to minimise wear - like the 'anti-bite guard' idea which is used on alloy freehub bodies. it'll probably be cheaper to buy a new frame.
Re: Dropout Repairs - Old Fashioned Engineering...
Aye, the throwaway society... A new frame is going to be ~£4k so am inclined to explore options. Cost is not the chief criteria as I like the frame, it's an old friend, new frames aren't that easy to come by and mine is Q/R and rim braked so obsolescent which makes getting a decent like for like replacement more difficult.
Re: Dropout Repairs - Old Fashioned Engineering...
Can you add some photos?
Would it be possible to extend the area over which the dropouts engage with the frame? That might allow more design options.
It doesn't have to be local. There's now a flourishing trade in machining to online orders. That can start either with a rough sketch and they do the CAD/ whatever and the metalwork, or you supply the CAD and they work to that.
Jonathan
Would it be possible to extend the area over which the dropouts engage with the frame? That might allow more design options.
It doesn't have to be local. There's now a flourishing trade in machining to online orders. That can start either with a rough sketch and they do the CAD/ whatever and the metalwork, or you supply the CAD and they work to that.
Jonathan
Re: Dropout Repairs - Old Fashioned Engineering...
@jdsk
The wear is very minor and hard to see. I think ~0.5mm each face but over the radius of the wheel, this puts alignment between the chain stays out by ~10mm. A lot on a close clearance road bike. The dropouts are obv vertical, forgot to mention that...
The wear is very minor and hard to see. I think ~0.5mm each face but over the radius of the wheel, this puts alignment between the chain stays out by ~10mm. A lot on a close clearance road bike. The dropouts are obv vertical, forgot to mention that...
Re: Dropout Repairs - Old Fashioned Engineering...
My thinking was that photos would inform the remedial options, rather than illustrate the wear...
Jonathan
Jonathan
Re: Dropout Repairs - Old Fashioned Engineering...
You've probably addressed this but bhat sort of QR are you using? Some are much better than others, I've used QR with fixed gear in horizontal drop outs without any issues.
Re: Dropout Repairs - Old Fashioned Engineering...
Aye. I was running Mavic's own which is a lightweight, external cam design. Switched to Shimano via Hope and they don't seem to make a lot of difference. Plenty of tension so probs not that.
I'll post some pics up in a bit.
Thanks all for your help.
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Re: Dropout Repairs - Old Fashioned Engineering...
Agree with the first part but not the latter. A small shim of stainless steel in 0.5mm would be relatively easy to cut and bend. Since it is mostly seeing a compressive force a good epoxy or methacrylate glue should hold it.fastpedaller wrote: ↑8 May 2021, 9:18am I'd suggest that the ideal 'fix' would be to machine the dropout slightly larger, and then 'face' it with steel to minimise wear - like the 'anti-bite guard' idea which is used on alloy freehub bodies. it'll probably be cheaper to buy a new frame.
Re: Dropout Repairs - Old Fashioned Engineering...
Yes, I'd be looking for compression rather than only injecting the load through the edge, and possibly using a larger area than the original.alexnharvey wrote: ↑8 May 2021, 12:31pmAgree with the first part but not the latter. A small shim of stainless steel in 0.5mm would be relatively easy to cut and bend. Since it is mostly seeing a compressive force a good epoxy or methacrylate glue should hold it.fastpedaller wrote: ↑8 May 2021, 9:18am I'd suggest that the ideal 'fix' would be to machine the dropout slightly larger, and then 'face' it with steel to minimise wear - like the 'anti-bite guard' idea which is used on alloy freehub bodies. it'll probably be cheaper to buy a new frame.
Jonathan
Re: Dropout Repairs - Old Fashioned Engineering...
Perhaps a sleeve over the end of the axle?
I.D. just enough to 'engage' the axle thread. O.D just enough to fill the gap.
Know anyone with a lathe?
I.D. just enough to 'engage' the axle thread. O.D just enough to fill the gap.
Know anyone with a lathe?
Re: Dropout Repairs - Old Fashioned Engineering...
This sounds OK to me.alexnharvey wrote: ↑8 May 2021, 12:31pmAgree with the first part but not the latter. A small shim of stainless steel in 0.5mm would be relatively easy to cut and bend. Since it is mostly seeing a compressive force a good epoxy or methacrylate glue should hold it.fastpedaller wrote: ↑8 May 2021, 9:18am I'd suggest that the ideal 'fix' would be to machine the dropout slightly larger, and then 'face' it with steel to minimise wear - like the 'anti-bite guard' idea which is used on alloy freehub bodies. it'll probably be cheaper to buy a new frame.
File out the dropout slots so when they are suitably shimmed the wheel sits central.
You can get stainless tube 10mm ID, 12mm OD ; bits of that would make ideal dropout liners, I should think.
https://www.ebay.co.uk/itm/402292859221 ... d586dc7e1f
....or maybe (as above) little sleeves to put over the axle, just less than the width of the dropout.
Bike fitting D.I.Y. .....http://wheel-easy.org.uk/wp-content/uploads/bike-set-up-2017a.pdf
Tracks in the Dales etc...http://www.flickr.com/photos/52358536@N06/collections/
Tracks in the Dales etc...http://www.flickr.com/photos/52358536@N06/collections/
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Re: Dropout Repairs - Old Fashioned Engineering...
That was my logic as well. I didn't realise the frame was £4k!alexnharvey wrote: ↑8 May 2021, 12:31pmAgree with the first part but not the latter. A small shim of stainless steel in 0.5mm would be relatively easy to cut and bend. Since it is mostly seeing a compressive force a good epoxy or methacrylate glue should hold it.fastpedaller wrote: ↑8 May 2021, 9:18am I'd suggest that the ideal 'fix' would be to machine the dropout slightly larger, and then 'face' it with steel to minimise wear - like the 'anti-bite guard' idea which is used on alloy freehub bodies. it'll probably be cheaper to buy a new frame.
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Re: Dropout Repairs - Old Fashioned Engineering...
It was the 'idea' of the anti-bite guard that I was referring to ie a 'harder surface' I wasn't envisaging just the edge, but exactly as alex explained it (better than I did )Jdsk wrote: ↑8 May 2021, 12:39pmYes, I'd be looking for compression rather than only injecting the load through the edge, and possibly using a larger area than the original.alexnharvey wrote: ↑8 May 2021, 12:31pmAgree with the first part but not the latter. A small shim of stainless steel in 0.5mm would be relatively easy to cut and bend. Since it is mostly seeing a compressive force a good epoxy or methacrylate glue should hold it.fastpedaller wrote: ↑8 May 2021, 9:18am I'd suggest that the ideal 'fix' would be to machine the dropout slightly larger, and then 'face' it with steel to minimise wear - like the 'anti-bite guard' idea which is used on alloy freehub bodies. it'll probably be cheaper to buy a new frame.
Jonathan
Re: Dropout Repairs - Old Fashioned Engineering...
If you want old fashioned engineering, then shim it with precision shims. These are readily available in a variety of sizes,in the form of car feelers gaugesboblo wrote: ↑8 May 2021, 9:07am I have a plastic bike with aluminium dropouts. Over the years, the front of the driveside and the rear of the non drive side have worn a bit so the wheel can sit a bit squiffy within the chain stays. Even with the QR's well tightened, the wheel can 'pull' over under the immense load of my Amazonian thighs...
I wondering about a bit of remedial work by a proper bicycle engineering company (rather than a shifter of Taiwan derived boxes...). I'm thinking of some sort of machined adapter or weld plus machining. I'd want to minimise damage to the carbon and paint so I may be asking too much.
Any experiences in fixing this and/or recommendations for pukka cycle engineering companies please? The grubbier and oilier the better as these tend to be a better bet.
Cut them up, find the one that's the correct thickness then glue it in place so it doesnt fall out when you take the wheel off.
I've fixed multiple worn suspension fork drop outs this way