Brompton rim wear indicator pictures


Well-Known Member
Hi all,

I've have my brommie (S6) for a year now, and have happily commuted on it daily to and from the station at both ends of my journey in all weather conditions (including snow...), while my daily mileage isn't particularly high, I am conscious of the fact that I will need to be on the lookout for wear and wondered if anybody had a definitive picture of what the brompton rim wear indicator looks like?

Googling it doesnt throw up anything definitive, but the brompton data sheet says that:
"As the rim wears, a void will appear in the braking surface. At this stage the rim should be replaced"

Is this a shimano style 'hole' void or something else?



i have been changing my rims when the indicator wears through. later years i have placed the brakes to wear on the inner side of the indicator, because there you can actually let them wear through the rim without the tire seat letting go and the soon to follow tyre explosion.

so nowadays i change the rim when brake surface turns soft if you try to dent it with the corner of a screwdriver.

how the newer double-walled rims can handle this i do not know.


Well-Known Member
i have been changing my rims when the indicator wears through
The OP is asking for advice for a Brompton that is one year old. This obviously has the double-wall-rims that are factory standard since 2013. Your pictures show the old single wall rims that were used in different flavors up to 2012 (some with, some w/o wear indicator, depending from the age of the bike). This had the wear indicator always visible from day one on and once it was gone through rim wear caused by the brakes the rim had to be exchanged. As you say this is not a 100% trustworthy indicator - sometimes the rim blows despite the indicator still looking perfectly fine.

The new double wall rims lack this kind of indicator - it is not visible from the start. I've not yet managed to brake through one of the new rims and therefore do not know how it really works with those rims. I can only assume that - in opposite to the old rims - when the wear limit of the rim is reached an indicator shows up (being inside the rim wall) instead of disappearing along with wear. As long as it does not everything is fine. However, I do not know if it really works that way, just that your explanation definitively does not apply to the rims of the OP.
Slightly off topic but I wonder why they don't like interlaced spokes? I've built Brompton wheels both ways and never had any issues. The factory wheels on mine were so woeful that I pulled them apart and rebuilt them in the first week. Barely enough tension for them to stand up!


berliner; regardless of new or old its a good idea not to excessively wear the rim next to where the tyre sits. failures there tend to cause more trouble. someone might have driven also the new rim to the bitter end and can show us similar photos ;)

even older rims than seen here lack the external indicator as well.

rogerzilla; to me interlaced spokes is really a solution searching for a problem. they make building and adjusting a wheel harder as you always tension two spokes at a time, and really cannot individually adjust them. i interlace only when i need to make room for disk brakes.

the wheel on the photos above, before and after rim exchange is a dished 130 mm wheel with a 10speed dura ace cassette.
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