Sks chromoplastic guard - rivets ripped out

[matticus]

(Think this happened when I whacked the bike against our gatepost ... didn't create a fatal problem but really should attempt a fix/bodge! The guard stays in place despite this failure. Which is nice.)

Would a reasonable bodge be a zip-tie thru the two holes that did have rivets in? (I pushed the rivets out before these pics.) Other cheap suggestions welcome.

Photos attached for clarity. No doubt SKS veterans will already be familiar with the parts, and best practice.

 

[EckyH]

Would a reasonable bodge be a zip-tie thru the two holes that did have rivets in?

I think so. But I would deburr the edges of the holes in the metal plate and the mudguard so that the makeshift solution proves the saying:

Nothing lasts as long as a provisional arrangement.

My solution would be stainless steel screws with flat heads on the inside of the mudguard and a washer and a locknut on the outside.

E.

 

[Jenkins]

Zip tie for a bodge, a couple of small nuts & bolts for a fix.

 

[Tom B]

I have this issue with my Chromos.

I thought it would just be a simple case of replacing the rivits, but they never seem to last. I've ended up with nuts and bolts, but usually view it as a warning the time is nigh for a new set.

 

[Oldhippy]

I need to get some aluminium ones for mine I think. I broke the rear in the middle and it's bodged with gorilla tape at present.

 

[Mark Grant]

Get a few big headed rivets and re rivet it.

 

[silva]

Cut a piece of 6 cm washing line with single stiff steel core, put it through the holes of the parts so that both protruding ends are equal, then bend them together.
Then, after a next whack against your gatepost, it will bend open abit, absorbing the energy thereby no damage, and solved by bending back.

 

[Big John]

Pop rivetter. Simples 👍

 

[silva]

The problem with steel pop rivets is that they may break themselves through the plastic when fitting them.
The problem with alu pop rivets, that risk that much less, is that alu is soft, vibrations will make the plastic wear them, causing play, more rattle, more wear, until the hole grew bigger than the rivet, and the connection coming loose.

Same with bolts, even with washers, when sufficiently tensioned they will compress the plastic, causing cracks, without enough tension, they will come loose.

So, I started to do what I described in previous post.
The problem ceased repeating.
If a guard / fender gets a hit, nothing breaks, instead the steel wire "gives", which can have quite some bend cycles before breaking.
And replacement is just another piece.

Just an idea I arrived at, many years ago, that proved itself all times since. Instead of bolting ziptie things together, use connections that can absorb energy, like pieces inner tyre, bend washing line.

The rear guard of my avatar bike is an assembly of 4 pieces of 4 different guards, connected together by overlaps with holes drilled through, then washing line pieces bend together.
If it gets a smack and deforms, I can get it back like it was by just pushing and bending again.

 

[presta]

When my Horizon was new I removed the bracket from the bottom of the front mudguard so that I could sandwich a mud flap under it, then refitted it with rivets. That was 25 years and 45,000 miles ago, and it's never been any problem. None of the other brackets that I didn't remove have been any problem either. I'm not sure what make they are, but as the Horizon was bottom of the Dawes range I expect they're cheaper ones than SKS.

If the rivets are pulling through it's because the heads are too small for soft material, make sure you use rivets with heads that are a good bit bigger than the holes, and if they aren't, use washers to spread the load.

 

[raleighnut]

I'd be looking round for a lamp/reflector that has similar spacing and screws on from inside the mudguard, they used to be quite common and were fitted after drilling the rivets out to a lot of touring bikes.

 

[Paulus]

I have had similar problems over the years. Small nuts and bolts are the solution. Two of my bikes are still running around with the mudguards fixed this way 10 years later.

 

[EckyH]

without enough tension, they will come loose.

This broad-brush assertion is wrong, because locknuts exist.

E.

 

[silva]

This broad-brush assertion is wrong, because locknuts exist.

E.

This broad-brush reading is wrong due to another interpretation than the intended.
I didn't say the nut moved, I said the bolt will come loose, due to the brittle chromoplastic around the guards 'mount hole, vibration will rattle out small chips of it, causing the bolt to come loose.
"Tough" soft mudguards, that is, some elasticity, suffer this much less, because these absorb the vibration energy, and, once the circumference around the mount hole has been deformed to a distance, loose contact, and no further deformation.

Washing line has, much like electrical wire, a tough plastic as insulation, which will, again, absorb vibration energy.
Much cheaper than bolts (lock)nuts washers, and, as said, can prevent shocks from cracking/breaking the guard, since it can again bend open, thereby allowing the guard to move instead of break. Move it back, bend the ends back together, and done, peddling further on the bike with no grown TO DO list.

 

[Regular.Cyclist]

I’ve previously used pop rivets on something similar, with a small washer on either side, with good results.