Rust hole in chain stay bridge

Hello lovely people,

Was wondering if anyone has an opinion on this -

Just bought a nice old frame that is perfect bar a rust hole in the chain stay bridge - see pic.

I imagine the rust will have spread inside, and so can anyone recommend the best way to preserve this - maybe something I can inject inside OR should I aim to get the frame repaired.?

OR... is it OK and I'm just being paranoid ?

Thanks all!

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That looks bad. I would get the bridge replaced before it spreads to the stays.

It's ok to leave it if you want to. Chainstay bridges are not even necessary really.
But I would at least paint it as it will rust on the outside now too.

It's a fairly simple repair if you do want it done professionally.

You could try to find some framesaver or other rust prevention solution like ACF50 to hold it off a while longer

yeah I think I will and also take @PhilDAS' advice in the meantime as this bike needs riding :) Thanks both.

Anyone recommend a frame repair outfit in North London?

Take it to Varonha frameworks. Worth trekking about of the river for.

You could definitely ride it as is, my crusty old brompton has been ridden to death with the bridge rotted through and fallen out.

I would fill it with rust inhibitor and plug the hole to stop anything getting in there and making it worse.

That hole won’t affect the rigidity of the frame and if it gets worse you will have plenty of warning. If it does get worse I would maybe replace it later down the line. A fix at this point if done tidily and correctly may just sort it out and go no further.

Getting it replaced would mean taking it somewhere to be fixed, waiting, getting it sprayed etc and I personally wouldn’t want to wait around and potentially end up paying more than the frame is worth.

I've gone for the low-tech approach for now -

• rust inhibitor
  
• some frame repair putty on the way
  
• stripped the stays & same treatment too as was some bubbling there & was paranoid
  
• going to give it a spray in keeping with its beater status
  
  

It's a proper ratty 60 year old Mercian Superlight, so it's either going to be awesome or a death trap. If former I'll get the stay bridge sorted properly.

thanks all

I have 3 Aende frames and a Bob Jackson with no chain stay bridges, I guess it's 531 being a Superlight? I'd sort the rust there and anywhere else and ride it. Any more pics of the frame?

I have one bad picture (frame is drying currently)

The red is rust inhibitor - stripped the bottom bracket in the end too... intention is to give it a garish 80s two-tone and then ride the fuck out of it.

The frame confuses me tho - seemed to be a legit superlight (lugs & geometry check out) yet I assumed there'd be a derailleur hanger on the drop out for the road version of this vintage.

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Nice :) deffo a Superlight. I wonder if someone has cut off the hanger? Long shot are really old campag Paris Roubaix dropouts with the ridges filed off?

Let me know when you want a “new” triangle and I’ll dig out one that’s cosmetically not great but not rusted through?

sorry didn't see this. Nope - no sign of hangar having been cut off or anything filed off. Wonder if it was just a custom single-speed setup, or intended to have a hub gear

Went all in, and stripped it down & re-painted it myself in the end.

Various injuries along the way with the power tools, but very happy! Next step is another coat of clear, and then I need to learn how to wheel build.

Rear drop outs are 130mm so I'm planning on a surly fixed/free hub on some H plus son rims I'm going to cannibalise from my trashed commuter

Learnt a lot, and the hot weather definitely helped with the painting process.

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Don’t wanna teach you to suck eggs but obviously be aware of the suicide dropouts if running fixed gear

Suicide dropouts?

Classic SS / fixed frames have horizontal dropouts facing backwards; this has semi horizontal facing forwards.

With just one gear your often going to put a lot of torque through + with braking etc that wheel has the potential to move in the dropouts. On rear facing it can kick to one side but is ultimately caught; with this frame the wheel could come flying out..

@sbbohr Thanks, but no need to worry - I no longer have the knees for fixed.

I rode fixed every winter with bikes having road dropouts and also did grass track using the same. Don't recall any issues. The only problem was chrome road dropouts and quick release, had to do the levers up so tight made a mark on the palm lol

Daft way of saying front facing dropouts IIRC. The fear being that you’ll skid the wheel completely out of the dropouts, although I’ve never actually heard of anyone doing it.

Sorry, I'm from the 70's. Dropouts were either road or track. Occasionally there were vertical dropouts but usually on TT machines.

I’ve never heard them called suicide dropouts and know framebuilders who have built purpose made fixed frames with forward facing dropouts as they are the better option of you want to run mudguards.

I'd always assumed that wheel slippage was possible, but unlikely. Last time I rode fixed I actually landed on my face, so it wasn't really part of the plan anyway.

Everyday is a learning day ;)

I have had a customer convert an older bike to fixed and walk in to the shop with the wheel absolutely jammed and pretty much out of the dropout; whether it was done up tight enough we will never know.

Never sure to trust a frame builder; without stirring the pot, a few old wrench’s always stood by this and my experience on paper aligns; beautiful aesthetic but built horrendously mechanically, frames not straight, wheel dished off to make it fit the frame etc…

Getting away from the point, SS, you will be fine I’m sure

I'm sorry but I have to disagree with your hypothesis.

I can see why it appears to make sense, with a forward facing horizontal dropout (ffhd) the upper run of chain pulls the axle up into the top of the dropout as you drive the pedals whereas when you resist them the lower run of chain applies its force inline (or at least much more so) with the slot in the dropout so all that's holding the axle in place is the nut/locknut clamping the top and bottom of the slot.

Where I think this falls down is when you consider the track end. In it's usual application on a track or fixed wheel road bicycle the chain applies its forces at an angle that is approximately in between the two scenarios in the ffhd and that angle is much the same whether you are looking at the top or bottom run of chain. Wheel pulling is of course not unknown with track ends but, in my experience at least, is much more common under driving than braking (I'd go as far as to say almost unheard of under braking) and usually there is more at play than a lack of torque in the wheelnut.

As previously mentioned, the angle the force is applied at is the same for driving and braking with a track end so if wheel slippage is more common under drive then something else is at play. I'd guess that the average rider is unable to push back with as much force as they drive forward and I'd also guess that the momentum of the bike moving forward keeps the wheel which is being decelerated from sliding forward in the track end.

If we now consider less common applications of the track end, bikes used for polo, speedway, artistic cyling and radball, we would find two common denominators between these applications. Smaller chainring sizes and lower gear ratios. Smaller chainrings will apply the forces to the axle/wheel much more inline with the slot in the end (akin to how it is applied when resisting the pedals in a ffhd) and the lower gear ratios would mean more torque (not sure if torque is quite correct but I'm sure you know what I mean) which would be more likely to cause a slippage. If a wheel can be adequately retained in a track end on these types of bikes then there's no reason why it cannot be adequately retained in a ffhd.

Where I know a ffhd does fall down is that they are often thinner than track ends and other modern dropout designs and as such the stub of a qr axle which protrudes beyond the lock nut can be longer than the dropout is thick so the qr skewer bottoms out on the axle before applying the proper clamping force to the dropout. This leads to the myth that it is impossible to hold a wheel in place in a ffhd.

Fuck knows why I picked this particular hill to die on...