Why do rear mudguards always fail at brake bridge?

[LittleWheelsandBig]

Leather should be waxed, greased or otherwise protected in a British climate. In California, not so much.

[Shuggie]

Also, how thick is the mudguard? I would think anything less than about 1mm wouldn't be all that durable.

Just measured it at 2.0mm, 2 coats of plastic (can’t tell what type) with a thin film of aluminium foil sandwiched between.

Replacement just arrived from Spa, has a rear reflector on it which I’m minded to remove, just in case

Cheers, Hugh

[Cudzoziemiec]

A reflector weighs just a few grams and will strain the mudguard a great deal less than the Secula.

[Shuggie]

Very true, have left it on & see how it goes

[hubner]

The instructions for fitting Portland metal mudguards says drilling a hole for direct mounting weakens it. They even sell a crimp on brake bridge bracket for direct mounting.

My suggestions:

use a brake bridge bracket or

direct mount:
make sure the surfaces around the hole are smooth to reduce stress risers,
use large washers, shaped to fit the mudguard curve, to reduce tension on mudguard
use rubber and/or leather washers to reduce vibration, although I would have thought rubber would be better.

[mrcharly-YHT]

Oops, first time this has ever happened to me!




SKS Chromoplastic P-45 which had been on my Sabbath September AR-2 for about 1800 road miles and the rear mudguard broke on Sunday. I had added a B&M Secula battery operated rear light onto the back at about 800 miles which probably created much more stress. Several weeks ago I had to tighten the seatstay bridge screw as it had become really loose mid ride, maybe I did it too tight. I had thought of adding threadlock but this fracture beat me to it.

Have used SKS chromoplastics P-35 and P-45 with the same rear lights before on other bikes without a problem but the metal clips on the P-35 do wear the guards and have snapped in the past.

Will be replacing the guard but putting the rear light elsewhere .

Cheers, Hugh

I don't like the look of that weld.

Maybe (hopefully) it is just the angle.

[Shuggie]

Think it’s just the angle and dirt