Clydes and Wheels,
 

A couple of weeks ago when I took my bike out for the first ride of the spring riding season, I noticed a tiny crack around one of the spoke holes. Sadly, the crack has worsened, and so now I am building a new wheel around my Velo Orange hub. My mechanic just ordered a new Velocity rim which hopefully will last at least as long as the cheaper Alex rim I was using.

Check your wheels folks. Though it is a huge bummer to be buying another wheel, or at least rim, it would have been much worse had the wheel failed in the middle of a big ride, or had I discovered the problem the day of a big ride.

We are going with the Dyad. Hopefully will be the right mix of durability but still reasonable weight.

Alex rims, while they're inexpensive, are usually built stouter than higher-priced rims. This is where a spoke tensiometer can help, or failing that, a musical tuner. Unless you've ridden over curbs or canyon-sized potholes, you've exceeded the upper limit on spoke tension, which cracked the rim. As a fellow clyde, I can appreciate your need to increase spoke tension to prevent spoke breakage from cyclic stressing, but as you've found out, too much is just as bad as too little.

There is a possiblity this happened early last fall when I hit something in the road and went down hard, though I assumed it was my front wheel that hit the crack/pothole, but it is possible my back wheel hit it, too.

The Velocity Dyad is a very nice rim. I have them in 36 holes on my second wheelset for rough road riding. That is now my primary wheelset with the Alexrims A23 now being the secondary. The builder said I could have easily gone to 32 holes, but said the 36 was a good choice for my uses. I also had Velocity Veloplugs (red) installed. The Veloplugs make tire mounting so easy that I only need levers for the initial install. YES, no more rim tape! I do not feel any weight increase, but these wheels have butted spokes and the Alex A23 OEM wheels had straight guage.

I got mine in silver with machined side walls and use cantilever brakes. The maker/model name decals were a bit large, but they came right off. Two years now and still good and still perfectly true..

Rims can crack. Any rim can crack. I’ve ridden a lot of expensive rims and a lot of cheap rims. I’ve ridden lots of different brands of rims as well. The number of ones that have cracked at the spoke holes are about evenly distributed between brands and cost. I’ve cracked Velocity rims, Mavic rims, Araya rims, Weinmann rims, and a bunch of others.

Cracking of a rim can occur with either tight spokes or loose spokes and both have a similar cause. Spokes are constantly undergoing tensioning and detensioning. Aluminum is a soft material and doesn’t really undergo constant flexing well but that constant tension/detension cycle is exactly what the rim is undergoing. There’s a pseudo Goldilocks tension level but the rim is still going to flex with each rotation. We big guys happen to make the rim flex more than smaller people so we (probably) tend to crack more rims.


You are also making a mistake in thinking that a cracked rim will result in a catastrophic failure. The wheel is not likely to collapse in the middle of a ride. The wheel may not stay true but it’s not going to fail in a mode that would result in a crash.

Dropping off curbs and hitting potholes aren’t going to cause the cracks. Cracks are more of a chronic problem. A localized impact...even a large one...will flex the rim but the rest of the wheel structure absorbs that impact. The aluminum, being soft, will likely absorb a lot of the energy of a single impact. The constant flexing during the tension/detension cycle is what does the damage to the aluminum.

I just run Gravel Wheels. Mavic Allroad and Shimano GRX. Double bonus is running very fat tires.

40mm Yksion on the Mavics
38mm GravelKing + on the GRX.

They're no Zipp 353 NSWs, but the tubeless are mounted, they hold air and can take a hit.

As all things Clydesdale / Athena your mileage may very (I guess literally in this case)

I recently found a brake track crack on a Velocity Chukker 700c rim on the back of one of my bikes. The rim is 15 years old, has 36 spokes, running on a Velo Orange hub. The brake track has quite a bit of wear. This bike was used on gravel roads a lot. I assume that the brake track wear plus all the rotational tensioning cycles over the years caused this failure. Probably buy another Chukker rim at this point. The rim failure was spotted by pulsing in the rim brake lever. This led me to inspect and find this problem. This rim had been installed on four different hubs over the years. Sorry to see it go.