Brompton rim longevity

[Sergeant Pluck]

While adding some air to my tyres, and marvelling at how my new chain tensioner and idlers look just like the old ones after about a month, I noticed that the brake tracks are alarmingly concave. The rear one is going to need changed soon. That’s with Koolstop salmon pads and well under 4k km. Are the Brompton rims as good as any in this respect or are there aftermarket ones that last longer?

[rogerzilla]

I think the main problem is that small rims always wear faster, not that they are particularly soft.   However, ceramic rims are made: https://www.sjscycles.co.uk/rims-tape/ryde-andra-20-16-x-1-38-349-css-alloy-rim-black-28-hole/

[Sergeant Pluck]

Worth considering, thanks RZ. Even the front wheel isn't great.

[Pickled Onion]

The normal use-case of a Brompton – stop-start, traffic, all weathers – does tend to eat rims. And, as Rog says, the fact there's a lot less to start with on a small wheel. Even so, 4,000 km sounds alarmingly short. I'd suggest investing in a rim measuring tool before writing it off on the basis of concavity. My last front lasted A Several of Bromptons before I changed the rim (though it was dangerously close to going bang at that point).

[Sergeant Pluck]

I do have a rim measuring tool somewhere but I’ll take a spin by Phoenix Cycles next week and see what they say. I also noticed that my brake blocks seem to have gone from “acceptable” to “change immediately” in what seems like a short period of time. I’ll have a proper look tomorrow when I change those.

[drossall]

I've just rebuilt both wheels on mine with Ryde Andras, in the last month or so. The bike is over a decade old and I've used it frequently, often daily (though obviously not in Covid) in the eight years I've had it. So I hadn't thought the wear unusual.

Sadly my rims aren't the posh ceramic ones linked by rogerzilla, but the ordinary basic ones. Turns out I'd had them put by for ages, having originally seen the issue developing a month or so before Covid struck. I timed the change about right, as one sidewall broke when I put a tyre lever on it

[Sergeant Pluck]

Quite a deep groove on one side due, I see, to a substantial bit of metal embedded in the brake block. But overall the rim will do for a while I think.

[toontra]

I've recently added brake-block inspection and clean to my routine service. 

Firstly inspect for any foreign bits embedded on the block surface & remove with a fine-point bradawl.  Then clean out the grooves with a blunt knife.  Then gently rough up the surface with a small, fine & flat file, and finally wipe clean with isopropyl (and do the rims at the same time).

I just can't abide the sound of grinding on ally rims 

Oh - and decent blocks to begin with - e.g. SwissStop.  The extra cost repays itself in rim wear and generally better braking and less noise.