Alloy rim wear rate

[rogerzilla]

Salmon pads. A sort of rusty colour. They contain iron oxide, which does something beneficial for wet braking. They're actually harder than some other pads - harder pads are less likely to embed rim chips and grit so are paradoxically more kind to your rims. The only downside to Kool-Stop salmons is that they might need a bit more toe-in; they can squeal rather loudly in the dry if this isn't done.

[Brucey]

you can characterise polymer compounds by 'shore hardness values'. Softer compounds may more superficially abrasive (because of the fillers in them) and vice versa.

Often a soft compound can work better because when something hard and sharp gets embedded, it can't push into the rim so hard; it just pushes into the pad instead.

Don't forget slots in the brake pads; if necessary cut your own, and make them large enough to clear the particles that get stuck in the brake block.

cheers

[reohn2]

Don't forget slots in the brake pads; if necessary cut your own, and make them large enough to clear the particles that get stuck in the brake block.

cheers

That's something I've thought about,BBB Tri/Techstops have a lot of slots/cutouts and that may make all the difference.Whatever they're the single most improvement to wet weather braking with no grit embedding on rims brakes I ever experienced.And I've tried quite a few over the years.
By far the worst for picking up grit are Shimano V brake pads.

[Brucey]

I think slots are really important. My logic is that any particle that embeds in the brake block towards the toe end of the pad has probably made some kind of rolling contact before becoming embedded. Every slot and every edge gives a chance for particles to escape and therefore not become embedded.

I've definitely seen marks which suggest that particles can come unstuck, move down the length of the pad and then get stuck again.

My idea (which I've habitually done for a few years now) is to cut slots the pads. I think it is best to cut them at a compound angle, so

- ~45 degrees to the forward tangent in the plane of the wheel (the idea being to help eject the debris with wheel rotation), and

- ~60 degrees inclined so that the leading edge of each slot is present acute to the rim, thus giving a better scraping action, and

- tapered slightly so that the slot is unlikely to clog lengthwise.

I cut them ~2mm deep in V brake inserts, and (if the insert is thick enough) I will recut them part way through the pad life. Three slots in a 70mm insert seems about right.

If you cut the slots too deep the brake block starts to deform too much in hard braking, and presumably this will vary with the pad compound.

Unfortunately it is difficult to do a controlled experiment; very often the pads pick up different amounts of crud from one side to the other anyway so 'slotted one side, plain the other' isn't a reliable test.

cheers

[Neil C]

Last winter I was having a lot of problems with grating brakes and the pads picking up ali bits. That was with Shimano pads.
It was even the subject of my first post on this forum in this thread - viewtopic.php?f=1&t=84736

I have changed to BBB Cantistops and have had no problems at all this winter. It could possibly be due to the slightly better conditions this winter but I'm not changing back. The BBBs last well, brake well and only cost £4.50 for two pairs. What's not to like!

[niggle]

+1 for BBB tristops and canti equivalents, they halted the wear rate of my tourer's rims after starting out with Shimano OEM front (V-brake) and vintage Fibrax on rear canti brake caused fairly rapid wear to begin with and the wear limit grooves nearly dissappeared in one winter- the latter were the worst but may been age hardened, though they did stop fine. The BBB pads are a bit quick wearing so it is a good thing they are reasonably priced.

I have also had good results with Kool Stop Salmon and Kool Stop Dual Compound, plus great results with even better braking with SwissStop Green in dual pivot brakes, and horrific rapid wear with Tektro OEM pads which I will never use again- now if I am pricing up Tektro brakes I allow for the cost of changing pads before use.

[coffeedrinkerUK]

You could give Ashima rim brake pads/blocks a go. They are soft but not so soft that they are uneconomical and they work well apart from extreme wet "and what does work in really bad conditions", it just requires more judgment. As others have said hard rubber doesn't work well and if it does it gets it can be grippy and jerky , that is where and when the rim damage happens. Ashima do the winter or mud ones with the grooves in as well. Iv got no vested interest but in the past iv had some lousy well known name brake pads that have put the wind up me on some of my regular downhill commutes. But yes pull your brake levers in 3 or 4 times in quick succession at times to discard some of the dirt.

[TimP]

I'm using the same set of Mavic E2 rims for over 30 years now. Still in good condition and braking is fine.

[JohnW]

I'm using the same set of Mavic E2 rims for over 30 years now. Still in good condition and braking is fine.

Yes, but how many miles have they done - in what conditions - and are you in a hilly or a flat area? I have a pair of wheels which were re-built with Open Pros about 5 years ago.........they are showing no signs of wear at all.........impressive? - not really, they've not been ridden.