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I've been wondering what the funny sound is coming from the back of my Mango Point AR when riding on the roads (thought it was bearings but nope) and found at least 6 cracks around the nipples on the back wheel.
I've been riding bikes for years (mainly off-road) but this is my first road bike and the first time I've ever seen this - I'm not light (85kg) but still not sure whats caused this to happen - I've only ever ridden this bike on the road.
I'm wondering what my options are to replace but would you still ride it with these cracks?
<img src="https://imgur.com/2ZOYpT1
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Personally I wouldn't ride it. That's not cracks on one spoke hole because you've walloped a wheel by the look of it.
How many more weak spots are there waiting to do the same? How many could go at once?
FWIW I am in a specific-bike FB group where the stock rims are i25 and i29 WTB and there are a lot of threads on there about this happening with them.
I recently re used one of those rims to build a new wheel on my hardtail, so I am looking at it every couple of rides. I haven't had an issue, but I err on the looser side of spoke tension on home built wheels.
It is either some batches of machine built wheels have been sent out with too high spoke tension or the rims have a fault. I hope it is the former!
Wheels should buckle and ding and flatspot well before spokes start to crack the spoke holes.
Thanks Dannyh I'll probably not take the risk. I've had them rims in the past on a full suss and they've been ok so hopefully just a bad batch perhaps
Same thing happened to me on an i19 rear, well it had gone quite a bit further but was covered in mud and only came to light when it got its annual wash. Was on a commuter running up and down the canal daily for 5 years so was fine with it. Managed to pick up the same rim on eBay for about £15 new. Swapped it over, and all’s good.
Maybe QC at WTB isn't AOK?
I've had cracks around spoke holes before, but I won't touch another WTB rim after what happened to me on an i29. I was riding on a tame flat trail (after something a bit more hectic), when the bars spun and I flew over them. I assumed i'd hit a rock but there was nothing nearby. Out of the blue the rim had separated at the join and obviously the tubeless tyre let go. Scared the shit out of me and badly hurt my quad. Had to limp several km back to the car park using the bike as a crutch and both brakes to get down steep hills.
Which rim is it? i19 is just the width? ST, frequency, ASYM. Looks like mayne an ST?
That sounds rough reeksy. I've never had any issues with them, they're decent rims and quite common.
Cracking spoke holes could be related to dodgy spoke tension, which seems a lot more likely than a fault with the rim. Also road salt could be a factor.
TBH it seems a common fault across a lot of modern rims.
You cant have a mavic XC317 26" with a 17mm internal width weigh 420g 20 years ago. Then make a 29x 19mm rim from basicly the same material (i19 were about 430g iirc?) and expect it to be as strong. Crests are even worse, they're 340g! Ive got them on my gravel bike because I got them for a bargain price but basicly expect them to die long before would be thought reasnoble.
It is either some batches of machine built wheels have been sent out with too high spoke tension or the rims have a fault. I hope it is the former!
125kgf max spoke tension for WTB rims.
Light weight rims will not deal with being over tensioned in the same way some older/heavier rims will.
Nipple washers can help spread the load.
Its a STP i19 rim, on closer inspection it seems the cracks are on every spoke coming from the drive side.
@Reeksy - your story has definitely put me off taking any chances of riding it for sure!
depending on how old the rim is, it's probably from when they specced a different alloy. As a few people mentioned, there's a number of stories about cracking wtb rims. Newer ones (and I'm talking like 4 or 5 years old and newer) used different alloys and are more crack proof. if it's under warranty, you'd be able to get them replaced. FWIW any that I've replaced (and i've seen this on ST, Asym and Frequency Team versions) have all been fine since.
It's not the only brand I've seen it happen on, and it is higher spoke tensions that cause it, but as everyone has said, not worth riding in that condition.
The replacement i19 I got, despite having the same specs on paper, had some visual differences and appeared to be about 1mm smaller on the inner width. Different batch or a design iteration I’m not sure.
Had i25 on my mtb in the past with no issue at all.