Rim Wear :-(
 

The rims on my commute bike are showing wear on the brake track. These are Mavic Open Pros. The grooved brake track is smooth now, with a perceptible but not really measurable ridge at the edge. I've ridden these rims for two years, every weekday, and a couple of centuries. The pads are KoolStop inserts for Shimano carriers.

How can I slow the rim wear? Replace brake pads more often? Clean rims frequently? Do those make much difference? How much longer might the rims last? I like these wheels and while I can rebuild them, I was not hoping to do so as often as every few years.

Keep 'em clean. Grit and water make for an efficient sanding action.

My OpenPro rims don't have a grooved brake track.

Have found that current Open Pro's aren't that great for rim wear, older ones (from 2000 ish) where much better, would be looking for a heavier duty rim for commuting as well, as Open Pros are light weight rims.

Agreed.

Ceramic plasma impregnated rims are out there ... then the rim is more abrasive , so the pad is different and they wear faster /.

setting up a place to wash your bike and its wheels daily is certainly worth a try.


Reality is what it is.

Living in wet PDX and loving Classic road bikes with rim brakes will be resolved by ...

N+1.. a newer bike with disc brakes ..

I've never fatigued a rim but wouldn't a lightweight road racing rim need replacement even with discs sooner or later? The spoke holes are undergoing cyclical loading and unloading every time the wheel goes around and the spokes are fatiguing too.

I would love a disc brake road bike because discs simply work super well but wheels may wear out anyway even with them. They would tend to increase the fatiguing of the spokes and spoke holes in the rim because they apply braking torque to the hub and can relax the trailing spokes a great deal.

My only experience with discs is with Sun Rhynolite rims which are very strong and have held up for almost a decade but it may be different with road racing rims.

IDK either, My go to bikes use heavier duty and smaller rims (discs are on a Bike Friday)

My Road bike lacks Mudguards, so It is only taken out on nice days ..

Maybe jyl is in the edge of metro PDX then has to go downtown daily ..he seems to prefer Road bikes .

Honestly, its a little hard to say. No one currently makes a disc specific road rim. There are a few CX rims. On a disc specific wheelset you can easily compensate by reinforcing the spoke holes.

Huh? There are rims that are not built to tolerate the abrasion from braking. Wouldn't you call that disc specific?

Brakes all work by applying Friction to the rotating surface.

with the exception of a electric motor-regenerative-brake scheme which turns the motor into a generator. and the drag is magnetic.

Replace brake pads more often? Maybe, but it's just as important to keep them clean and properly adjusted. I only replace pads when they are worn out or get grit embedded in them I can't remove by cleaning or refacing the pads.

Clean rims frequently? Absolutely, I keep a quart bottle of 90% alcohol on my bench with paper shop towels. It takes about a minute each to clean the rims before putting the bike away. Open the brakes and wipe off any obvious grit there as well.

Do those make much difference? Oh yeah

How much longer might the rims last? It depends a lot on riding conditions. Wet roads with lots of sand and grit can chew up rims in a hurry. If you only ride on well paved roads on clear dry days, not so much. Average conditions, my WAG would be 50%+ increase in rim life.

How can I slow rim wear? Stay off the brakes :thumb:

I just put Open Pros on my road bike. I'm interested to see how they hold up. Most of my riding is on fairly flat roads and rolling hills through rural areas, so I'm not on the brakes a lot.

The number one thing the OP can do to reduce rim wear is move. It's nearly impossible to wear through a rim on the road under normal riding conditions, but commuting in Portlands wet weather means the shoes will constantly pick up rod grit and be unusually abrasive.

OTOH- I believe the rim wear issue is overblown, possible even for Portland commuters. It takes a long while to wear the brake track to where failure is a real possibility. This isn't to say it's impossible, just that it's a long slow process, and most wheels die accidental deaths beforehand.

The strength needs are proportional to tire width and pressure, so if riding with narrow tires at 100psi, you can let the rim wear more than someone riding wider tires at similar pressures. IME- you can wear away roughly 1/2 the original section at the thinnest place, so if concerned, use a dental caliper or improvised gauge to measure a new rim (of th same kind) and yours and see how you're actually doing.

Or ride until you feel the pulsing that's indicative of the rim bowing out under pressure stress. When riding a rim, I'm not sure about I over-inflate 15-20% then bleed back to riding pressure. This gives me a pressure test at higher stress and ensures a safety margin when riding.

I, for one, cannot wait until I can claim to have worn out a rim. Ride it till it makes you too nervous, and hang it on the wall as a trophy :).

The disc specific rims are all wider than a typical road rim (20-25mm external) for 23-25mm tires. Maybe I'm missing one, but they're difficult to find.

It depends also on rim quality. I've never seen a good rim break while inflating a tire, however worn out, but witnessed a couple of crappy ones do.

Thanks. I have some new Open Pros here, so I will try to compare rim thickness. BTW, my Open Pros have a machined brake track with fine concentric grooving, about as fine as a phonograph record's grooves.

I have now replaced the pads. The old ones were about 1.5 years old, maybe 2/3rds worn down, looked pretty bad. I have not been in the habit of regularly cleaning either pads or rim brake track, but will try to do so now.

Those are "scroll marks" left by the point of the cutting tool as it spirals in (or out) when the rim is machined. You see the same on many lathe turned objects, and they're incidental to the process. There's very little depth so it's not relevant when they smooth out. If the rim has just become smooth, you've probably only seen less than 10% or so of the service life worn off.

It's actually a deliberate finish.

Rims can be used as extruded and anodized but the brake wear will be ugly and uneven until all the anodizing wears through. They're smoother as-extruded than after machining. Only the lowest-end machined aluminum components have such a rough finish left on them incidentally. At the price of most non-entry-level wheelsets they could surely spec a finer finish if they wanted.

yes, if by deliberate, you mean that the makers left the scroll marks rather than make the effort to eliminate them.

The scroll marks are the result of the radial tool path while the rim is turning. The pitch is equal to the feed (radial distance per revolution) so coarse scroll marks are the result of fast feed rates whose benefit is a shorter cycle time and lower cost. There are various ways to eliminate scroll marks, but they all have drawbacks and raise production cost. OTOH- if you do a great job eliminating any hint of scroll marks, how would buyers know the rim has machined sidewalls.

So it's smarter to leave them in and let marketing sell the look, than to spend the dough to eliminate them.

I've worn through the anodizing on a new wheel. The brake pads leave streaks before they establish a wear track all the way around a rim.

Ridges may also increase the braking power slightly by adding surface area.

Only the very lowest end parts have tool marks which are that coarse. They leave the ridges to hide the streaks and possibly increase braking power a bit.

I don't know why you bring up anodized rims when we;re speaking about machined brake tracks. Anyway, nothing you posted contradicts my statement that scroll marks are the result of machining the sides. And, yes, pricier rims may (but not necessarily) have finer scroll marks, since the coarseness of the marks indicate a fast feed rate and shorter machining cycle time.

If the brake tracks weren't machined, they'd be anodized as they were extruded, and streaks would wear into the anodizing as they broke in.

The ridges conceal developing streaks.

Road whees have grooves which are coarser than the cheapest hub. That's because they were put there deliberately. They may have been made by a triangular cermet insert which could be indexed twice when it got dull, then reversed and indexed twice more, but it's just not germane. They are not incidental.

FWIW, my commuter has Mavic Open Pro rims laced up to DT Swiss Disc hubs. After 16,000+ fairly miles on some pretty rough roads the rims are still true and there is no cracking visible around any of the spoke holes. Disc brakes are pretty nice for a daily commuter around here.

Whatever you say. I've said my piece, you've said yours and readers can draw their own conclusions. It just doesn't warrant big time debate.