Cracked rim - How long till it breaks

nick123

Likes Bikes
Hey guys,

So today was riding and noticed a BIG crack in my rim. Back rim, goes the whole width of the rim, the rim is a sunringle equilizer 31.
Just wondering if anyone knows how long I could ride with it until it snaps, etc.
Pics of the crack

Screen shot 2013-01-14 at 9.09.22 PM.jpgScreen shot 2013-01-14 at 9.09.32 PM.jpgScreen shot 2013-01-14 at 9.09.39 PM.jpgScreen shot 2013-01-14 at 9.09.49 PM.jpgScreen shot 2013-01-14 at 9.09.58 PM.jpgScreen shot 2013-01-14 at 9.10.06 PM.jpgScreen shot 2013-01-14 at 9.10.17 PM.jpg

Thanks guys! any comments are welcome :)
Nick
 

T-Rex

Template denier
It's a bit hard to tell what's going on since only one of your photos is in focus, so the following is a bit of guesswork.

Given it looks like a perfectly straight crack half way between two spokes, I'm guessing it's a "pinned" rim (spot welded), and you've cracked the lump of alloy that the join is spot welded to. If the crack is exactly opposite your valve, then my guess is correct.

I've done similar to a MTX in the past. If the spokes are correctly tensioned, they will hold the rim together pretty well. I had one that was cracked all the way through the join AND the vavle hole, it was still ridable.

Not ideal, but if you ride smoothly, it's ok. However, one day you'll case a jump, and it'll let go.

You can buy the same rim and relace the spokes and hub across, pretty straightforward. That's what I would do.
 

nick123

Likes Bikes
It's a bit hard to tell what's going on since only one of your photos is in focus, so the following is a bit of guesswork.

Given it looks like a perfectly straight crack half way between two spokes, I'm guessing it's a "pinned" rim (spot welded), and you've cracked the lump of alloy that the join is spot welded to. If the crack is exactly opposite your valve, then my guess is correct.

I've done similar to a MTX in the past. If the spokes are correctly tensioned, they will hold the rim together pretty well. I had one that was cracked all the way through the join AND the vavle hole, it was still ridable.

Not ideal, but if you ride smoothly, it's ok. However, one day you'll case a jump, and it'll let go.

You can buy the same rim and relace the spokes and hub across, pretty straightforward. That's what I would do.

Thanks for the help! yes it is opposite the valve, so your right. Spot weld has cracked!
Well I'm riding DH so that is certainly not "smooth riding". Say its time for a new rim.
More photos here!
Screen shot 2013-01-14 at 9.37.18 PM.jpgScreen shot 2013-01-14 at 9.37.29 PM.jpgScreen shot 2013-01-14 at 9.37.33 PM.jpg
 

driftking

Wheel size expert
Equalizers are shit I have one on front with a crack. It's horizontal though not vertical. If is is full width of the rim id bin it. Althoufht I'm still running mine,but I'm broke.
 

MTB Wanabe

Likes Dirt
Hey guys,

So today was riding and noticed a BIG crack in my rim. Back rim, goes the whole width of the rim, the rim is a sunringle equilizer 31.
Just wondering if anyone knows how long I could ride with it until it snaps, etc.
Pics of the crack

View attachment 254020View attachment 254021View attachment 254022View attachment 254023View attachment 254024View attachment 254025View attachment 254026

Thanks guys! any comments are welcome :)
Nick
Nick,

Is that "crack" opposite the valve hole as it looks like the rim joint. If this is the case, the rim should be right as it just looks like the rim bead at the joint is just misaligned. Try taking the tyre off and displacing the rim joint alignment, if you can't slide the 2 mating surfaces against one another then the sleeve or pins (the structural elements in a non-welded rim joint) are still fine and the rim is still good. If your still concerned, err on the side of safety and replace the rim particularly if you ride the bike hard. MTX 31's are relatively cheap compared to breaking yourself.

Good luck

Edit: What T-Rex said, who said reading all posts is over-rated, doh!!!!
 
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nick123

Likes Bikes
Nick,

Is that "crack" opposite the valve hole as it looks like the rim joint. If this is the case, the rim should be right as it just looks like the rim bead at the joint is just misaligned. Try taking the tyre off and displacing the rim joint alignment, if you can't slide the 2 mating surfaces against one another then the sleeve or pins (the structural elements in a non-welded rim joint) are still fine and the rim is still good. If your still concerned, err on the side of safety and replace the rim particularly if you ride the bike hard. MTX 31's are relatively cheap compared to breaking yourself.

Good luck

Edit: What T-Rex said, who said reading all posts is over-rated, doh!!!!
It is indeed opposite the valve hole! So it looks like a crack in the weld.
Im thinking of upgrading to mavic 721s or something along those lines! Thanks for your help :)
 

T-Rex

Template denier
721 would be a downgrade IMO, not an upgrade. Very soft and small outer diameter, prone to rolling the tyre off if you get a flat spot. See if you can get another rim with the same ERD, so you can just transfer it across. +1 for the MTX33 suggested above, a good value rim.
 

Shredden

Knows his goats
Leave the structural sticker on it will hold it together.

I cracked my 721 in the same spot riding over a 30cm high square edge at about 30kmh, have done about 7 days riding on it since with no issues.

Same rim also now has 3 cracks running off the spoke holes, as well as one about an inch long running like lengthways along the rim bead bit from bending back a dint. Might be time for a new rim ay.
 

The Duckmeister

Eats Squid
It is indeed opposite the valve hole! So it looks like a crack in the weld.
Im thinking of upgrading to mavic 721s or something along those lines! Thanks for your help :)
It's not a crack in the weld, because there isn't a weld to crack. :wink:. It's a pinned joint, and it's not at all unusual for the join to be visible like that. Even a slight misalignment of the ends of the rim section isn't all that unusual, especially on wheels that do cop a bit of a hiding. You can squeeze the sidewalls of the rim carefully with multigrips to smooth out the joint (the pins are deeper in the rim, inside the "shoulders" that form the centre channel). If the joint isn't moving then it's fine.
 

skwiz05

Likes Bikes and Dirt
Just looks like you flat spotted near the join and it deformed the edge of the rim a touch....
Straiten and keep riding I'd say.
Ive got a rear WTB 32 FR I-beam rim thats had a flat spot, and caused a crack across the valve hole........
I de-laced it, then using blocks of wood, car hyraulic jack under the towball of the car (on top of rim on wood blocks), managed to remove the flat spot........And its still going strong 3 years on, with plenty of abuse.

Then ive also experienced this below.....with a perfectly good rim, one jump, land and rim explodes.....
 

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markb84

Likes Dirt
The guy's asking a serious question, and your answer is just fucking stupid.
It's got atleast 32 mins. left in it. And that's ride time.
I think it will last until the precise moment you stop thinking about the fact that it might break and let your guard down, at that point it will explode into three gazillion pieces at least 12 of which will embed in your skull.

Don't ride stuff when you know it's broken (says the guy who rode his cracked frame about 3 times after finding the crack.....)
 
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