The orange pad is the salmon pad.
Originally Posted by
sweeks
I've had this problem on a couple of my folders with 20" rims. Specifically, "Kinetix Comp", which were original on a Dahon and a Tern. I had severe rim wear, and was getting only about 2,000 miles on a rim. After 2 replacements, I switched to a Sun-Ringle "Rhyno Lite" rim, which has lasted almost 4,000 miles with little evidence of wear. The Rhyno Lite rim is a few mm wider than the Kinetix, which probably ameliorates a problem with rim fractures which were probably due in large part to tires that were technically too wide.
My rim problems were only on the rear wheel, in spite of my greater reliance on the front brake. I speculate that the rear wheel gets a lot of abrasive dust thrown up by the front wheel, though this does not account for the better survival of the Rhyno Lite rim. Another possibility is that the alloy from which the Kinetix rim is made is softer than that used in the Rhyno Lite.
As for the differential rim wear between the sides, I have nothing to add other than that I have observed the same thing. Can't explain it.
I doubt it has to do with one shoe hitting the rim before the other. The fraction of a second before both shoes are engaged is negligible compared to the time the shoes are both wearing. There would seem to be little difference in the pressure on the two shoes other than a minor variation between the springs, which is much less than the actual braking pressure. I have noticed that between wear on front and rear wheels, the wear is greatest on the side opposite the cable entry (drive side on the rear wheel and left side on the front). I have no good explanation for this either.
I also noticed that there is greater wear on the front non-drive side compared to the front drive side, which is also opposite of where the brake cable comes in from. But since the front wears so much slower than the rear, the difference between the sides of the front rim is less noticeable.
Maybe the non-symmetric wear has to do with the full length brake cable housing without a cable stop on the frame that Dahon uses? Maybe without a cable stop, when the cable is pulled, the housing is free to move, and diverts more pressure to the drive side rear or non-drive side front, opposite to where the cable comes from.
On my very old Speed TR, the Kinetix rear rim lasted 4000km before the drive side wall tore open, and that one I didn't clean very often. But the brake cable ran on the outside of the frame, with very tight fitting braze-on housing holders. The front rim after 6000-8000km is still fine, the front hub was the first to wear out, with the inner diameter widening itself and the cartridge bearing slipping from side to side.
On the newer Vigor D9, the old French made rear rim (forgot the brand) lasted up to 2000km before the drive side wear line was gone, and I also didn't clean very often. The new rim I built with Kinlin DDT32 is maybe at 1500km and shows significant drive side wear, even though I clean the rims and brake pads every 5-6 weeks. I scrape the pads with a knife until the dirty gray film is gone, revealing the original orange color of the Koolstop. There are no cable housing holders though on the Vigor frame, it simply runs internally in the frame, with a rubber stopper that covers the opening of the frame where the cable comes out of, and the housing is free to move around. Maybe this looseness causes more non-symmetric rim wear compared to the Speed TR with the firmer grip on the cable housing.
Maybe the only solution is to go for disc brakes, like the K3 Plus. I was thinking about the possibility of building it with Sturmey Archer cs rk3 3 speed cassette hub with disc brake, although it's usually only available in 32/36 holes.