How do you know if your rims are worn?

[Glover Fan]

Have you done a lot of wet rides?  Rim wear is many times worse when wet than dry, and you can't be expected to keep on cleaning and drying your rims and pads during rides.

Well it gets used through the winter, and I do like hilly rides, so although I don't use the brakes often, when I do it will be applying a lot of heat into the rims.

I suppose disappointed is the wrong word. Surprised would be more accurate, I will know for the future to put a little bit of money aside ready for new wheels. At the moment I may need to be rescued by a credit card.

[contango]

Have you done a lot of wet rides?  Rim wear is many times worse when wet than dry, and you can't be expected to keep on cleaning and drying your rims and pads during rides.

Well it gets used through the winter, and I do like hilly rides, so although I don't use the brakes often, when I do it will be applying a lot of heat into the rims.

I suppose disappointed is the wrong word. Surprised would be more accurate, I will know for the future to put a little bit of money aside ready for new wheels. At the moment I may need to be rescued by a credit card.

Can you buy a replacement rim and transfer the spokes and hub across?

[andrew_s]

If they're so concave your finger fits snugly in, you're living on borrowed time.

If it feels like your fingertip fits in, the hook part of the rim is bent outwards by the tyre pressure. Then when you brake the rim gets squeezed back in, and it takes very little bending back and forth before it breaks. It's a case of reducing the tyre pressure and returning directly home, trying to avoid the use of the brake on that wheel, and replace the rim/wheel before riding on it again.

[Rhys W]

That figures - in the incident I witnessed it went with a very loud bang and the hook was detached from the sidewall on a 10-15cm length.

[orienteer]

Have you done a lot of wet rides?  Rim wear is many times worse when wet than dry, and you can't be expected to keep on cleaning and drying your rims and pads during rides.

Well it gets used through the winter, and I do like hilly rides, so although I don't use the brakes often, when I do it will be applying a lot of heat into the rims.

I suppose disappointed is the wrong word. Surprised would be more accurate, I will know for the future to put a little bit of money aside ready for new wheels. At the moment I may need to be rescued by a credit card.

Can you buy a replacement rim and transfer the spokes and hub across?

I've done this on front a wheel, just tape the new rim to the old, loosen all spokes and swap over spoke by spoke, then adjust tensions to maintain symmetry.

Now I have to replace an asymmetric rear wheelrim, I'm leaving it to an expert!

[mrcharly-YHT]

It's no harder. Just do the tensioning in the frame, check that the rim remains central in the frame.

[Greenbank]

Search eBay for:

BICYCLE RIM GAUGE DEUXIEME GAUGE

They're £4 or so and make it easy to measure rim width without needing to do the spoke trick.

And to explain how I use it:-

I check the rim thickness using one of these gauges a few times a year; usually when I'm mending a puncture (at home) or giving the bike a service. It only takes a few minutes to deflate the tyres, check the thickness at 5 or 6 points around the rim (both sides) and then pump the tyres back up to normal pressure.

I used to keep a note of rim usage and wear levels on cyclogs but I stopped using that ages ago. I'll just retire the rim when it gets to a dangerous level (somewhere around 1.0mm - the exact level depends on the rim and what bike it's mounted on).

More frequently (every 2 weeks or so) I keep an eye on the state of the braking surface (looking/feeling for concavity), check brake block state and alignment and check for any swarf in the brake pads.

Fate has conspired such that I haven't actually retired a single rim yet. My Audaxing and commuting has been spread over various bikes and wheels (SON hubbed wheels in the winter, lighter wheels in summer with battery powered lights, different fixed rear wheels with different sized sprockets on, PowerTap rear, etc) and the most worn rims of all (the SON front in Excellight S.S.C. from Bike+ and an Open Pro fixed rear) were on the old Tempo when it was stolen.

When I do retire one I intend to transplant the spokes/hub into a new rim myself for my first full wheelbuild and then measure the old rim and then cut it up to see what the cross section looks like and check to see how even the wear is.

Reminds me, I'm due a check of the rims on my commuter and fixed.

[zigzag]

i'd be very interested to see cross section of Lars's ksyrium sl rim that failed due to wear just before bcm. i have been using the wheel for four years and the braking track is pretty concave (i run a new front wheel now, btw), but just wondering how many safe miles i can get out of an old one as it is still dead true and bearings are smooth. i'll take a pic later on.

[Glover Fan]

I've just bought a pair of Shimano RS10's to replace the RS10's that are already on there. £90 for the pair which is a steal.

It will put my mind at rest, at least.

[Ham]

Just adding if anyone is about to throw out a rear that they think is not worth riding, I'm looking for a wheel (Shimano 9 speed) to use as and when on a trainer, so could be persuarded to part with a few shillings. No worries about roadworthiness, none about true (as long as it can still rotate and no braking surface required. Only caveat that it does need to be run at high pressure.

[Cudzoziemiec]

Interesting thread. I've no idea how many miles the rims on my oldest bike have done.

The other test is to pump up your tyres to ~150% of normal pressure.

However DON'T do this the day before a big ride as this is a destructive test if they fail and DO wear ear defenders if you think they might fail.

And maybe eye protection?

[marcusjb]

Just adding if anyone is about to throw out a rear that they think is not worth riding, I'm looking for a wheel (Shimano 9 speed) to use as and when on a trainer, so could be persuarded to part with a few shillings. No worries about roadworthiness, none about true (as long as it can still rotate and no braking surface required. Only caveat that it does need to be run at high pressure.

Might be a bit wide for you - I have a Cannondale hub, 36 spoke with a Mavic T520 rim.  Shimano freehub. 

Bearings are a bit rough in the hub - but it's round and spins.

We're in W4 if you want it (drop me a PM - I am away this weekend though).

[Biggsy]

Interesting thread. I've no idea how many miles the rims on my oldest bike have done.

The other test is to pump up your tyres to ~150% of normal pressure.

However DON'T do this the day before a big ride as this is a destructive test if they fail and DO wear ear defenders if you think they might fail.

And maybe eye protection?

And have a spare inner tube standing by.  The tube may explode if the rim fails or if the tyre blows off.

[zigzag]

my mate who works in a bike shop says they sell/replace loads and loads of wheels because of worn out/split rims. commuters are usually very surprised that after one year's of riding to work the wheel needs to be thrown away (as it is usually cheaper to get new rather than pay for a new rim(s) plus wheelbuilding costs). then they start inquiring about the disc brake equipped bikes.

[numbnuts]

I have Sun CR18 rims the rear rim lasted 10,000 miles before it split, the front one has done 28,000 miles and it has only worn down .5mm from brand new.

[edscoble]

my mate who works in a bike shop says they sell/replace loads and loads of wheels because of worn out/split rims. commuters are usually very surprised that after one year's of riding to work the wheel needs to be thrown away (as it is usually cheaper to get new rather than pay for a new rim(s) plus wheelbuilding costs). then they start inquiring about the disc brake equipped bikes.

I observe exactly the same thing in my shop, like I said earlier, it's one of those issue where people don't think it'll happen to them.

To be fair, the majority of commuters does little to no maintenance on their bicycle, the last one I got was very surprised and angry at the fact I told him it would cost him £250 to fix his bicycle, despite the fact he "only" own it for 4 years.

Wasn't very nice to be called a Nazi and to "go back home" just because I was trying to be realistic.

[mattc]

Interesting thread. I've no idea how many miles the rims on my oldest bike have done.

The other test is to pump up your tyres to ~150% of normal pressure.

However DON'T do this the day before a big ride as this is a destructive test if they fail and DO wear ear defenders if you think they might fail.

And maybe eye protection?

And have a spare inner tube standing by.  The tube may explode if the rim fails or if the tyre blows off.

And a spare tyre? Can they get damaged?

(Never been brave enough to try this ... )

[Biggsy]

Nah, the tyre will be ok, unless perhaps it was already faulty or damaged.

[andrew_s]

And have a spare inner tube standing by.  The tube may will explode if the rim fails or if the tyre blows off.

It's also worth retreating to the full length of the track pump hose. Sometimes the rim bead hook can come off at one end of the broken section and flail round

[Biggsy]

I was just in time once to let air out as the tube started ballooning from a tyre that popped off during a ride - with my unprotected ear dangerously close to a potential big bang.  But you've got little chance if the pressure is much higher than normal, and no chance if a valve cap is fitted!

[zigzag]

i'd be very interested to see cross section of Lars's ksyrium sl rim that failed due to wear just before bcm. i have been using the wheel for four years and the braking track is pretty concave (i run a new front wheel now, btw), but just wondering how many safe miles i can get out of an old one as it is still dead true and bearings are smooth. i'll take a pic later on.

is there any life left in this rim (for riding in dry only)?

[mrcharly-YHT]

If you don't use your brakes, probably.

[andrew_s]

That's brake wear with no bending, and as such is OK to ride on provided that it looks the same with a fully inflated tyre on it.

It's at the point where you should check it every couple or three weeks, either using a gauge or by a pressure test (take it up to 130-140psi and check there's no increase in the amount of concavity in the braking surface).

If it stays largely dry and you use rim friendly brake blocks you may get the rest of the summer out of it (1500-2000 miles).

[Jurek]

DSC04013.JPG by jurekb, on Flickr][/url]

Ksyrium rim retired due to concavity of the braking surfaces (more evident on the rh side) after ~ 10,000 miles.
Despite the concavity, there's a surprising amount of material still present, and if anything, the retirement may've been a bit premature.

[jane]

Speaking as someone who has suffered an exploding rim which had far less wear than that when checked a couple of days before, I wouldn't risk it.  Admittedly, the weather was showery and I had also been down some rough tracks and I was on a very steep downhill in the Peak District and braking very hard due to oncoming car, but it's not an experience I'd care to relive.