Noticed a crack inside my rim where the valve hole is.
About 5mm long.

Just Mot’d the Bastd car and bought some new brakes so Bike tokens are used up for the month.
Will i die if i still ride it?

m8’s been using some rim that have several hairline crack’s around the eyelets (for about a year now), and still hasn’t died… not something I’d risk, but then he’s about half my weight.

Just keep an eye on it, if it starts growing quickly, replace.

I cracked a rim in the same way.
I first noticed there was something wrong when I saw the edges of the rim bulging outwards without realising what was causing it.
It was only when I got a puncture that wouldn’t seal that I took the tyre off to have a look.
The crack had started to open up and the sharp edges had cut the rim strip.

If the edges of your rim are still parallel then the crack hasn’t opened up and you’re probably OK to ride it for a while.

If you shock the wheel, ie do any jumping, or its a wheel on the rear of a hardtail ie no suspension it can fail suddenly with no warning… There are loads of cheap wheels on the classifieds… i wouldnt risk it.

If it’s only around the eyelets, it might be OK for a bit. If it’s the sidewall – replace! I’ve blown 2 rim sidewalls on my commuter in a year (V brakes are great!) and it’s pretty nasty – 60 PSI tube going flat instantly. Fortunately wasn’t in traffic either time!

Thanks for your comments.
I’ll get a new rim – and ask the lbs to show me how to build it.

I’ve been riding DH (whistler and the alps) for 2 years on a cracked rim. Granted, the rim is probably stronger in the first place, but I can’t see the problem. A rim isnt going to spontaneously combust in anything other than a big stack – it’ll just get progressively weaker and bend more out of shape. When its more flatspotted than you’d like, replace it. Till then, ride it

If you shock the wheel, ie do any jumping, or its a wheel on the rear of a hardtail ie no suspension it can fail suddenly with no warning…

You won’t even need to do that. I had a wheel fail because of a cracked rim, because I turned on a camber with my weight over the front wheel. (Poor description!). The rim collapsed, wheel folded and I went over the bars. Very slow speed so no injury.

Your wheel may not fail, and perhaps you won’t damage yourself. It’s up to you how much you want to risk, though……

5lab – Member
I’ve been riding DH (whistler and the alps) for 2 years on a cracked rim. Granted, the rim is probably stronger in the first place, but I can’t see the problem. A rim isnt going to spontaneously combust in anything other than a big stack – it’ll just get progressively weaker and bend more out of shape. When its more flatspotted than you’d like, replace it. Till then, ride it

Sorry but that’s just stupid advice.

Your crack is likely to be getting bigger. Maybe slowly, but if a crack has develop you’d have to ask why?

Since the wheel holds you off the ground, why would you carry on riding with a damaged one?

Have a think about what happens when you bank your bike over at speed – one side of the rim (the bit below the crack) will twist against the ground, and eventually this will collapse (as mine above did) taking the weight of bike and rider on a small piece of breaking metal. End result, rider hits the ground. Nothing to do with flat-spotting, unless all you do is ride in a straight line.

This managed another 40k at the dyfi

Aluminium does not progressively get weaker and bend more out of shape… it just fails. Especially the alloy used in bikes.