ratrod

I have a bend in the braking surface, it's folding in. There is no issue with the rim being out of true, its just folding in. I am running deep Vs on an old road frame converted to fixed. I weigh 130 lbs, with all my books 160 lbs at most and only occasionally. I don't jump off curbs and avoid almost all potholes. I don't use a rear brake. This is the second deep V rim that this has happened to. I have been riding on this rim for less than 3 months. This frame has never been in an accident, it is 25 years old-but it was not ridden for the first 13 years. The frame has always been difficult to balance with no hands, you have to lean a bit to the left. (No its not dish, I have checked and it doesn't matter which wheel set is used you need to lean a bit) Could this be a sign that the frame is out of alignment? Could that be the reason behind the problems with the rims? Has anyone had any similar problems with deep Vs? I did run another wheel set for about 6 months with no problems too.
Thanks....

FlatTop

Hey, great username.

I'm not familiar with those particular rims, but somehow I can't see this problem as being a frame issue. Is there a fairly sharp dip or line developing radially in the brake surface? Maybe the wheel is taking a beating from the tire not being inflated enough...a tire with enough air pressure transmits less stress to the wheel.

Maybe there's something I don't understand about the forces fixed riding puts on wheels, but I can't see this happening in normal riding, only using the wheel for power and braking.

waterrockets 

My brother-in-law and I are both riding Deep Vs that I built. I weigh 185. He started at 230 and is now down to 190. Our Deep Vs look like new -- the first pair has 2000 miles on it.

All I can think is that you're underinflated and hitting a pothole. I'd just straighten it as much as possible with an adjustable wrench, then inflate tires to max pressure. You can adjust the brake pads further away from the tire to keep them away from the worst bent area, which will lower the pulsating feel.

TallRider

ratrod - please describe the bend more carefully. Is it bent radially? Longitudinally?
Better yet, post pictures.
For now, all I can guess is the same thing the other two responders did.
The Deep V is known as a very durable rim, and lots of fixed riders use it.

ratrod

I don't own a camera so no pics. The bend starts at the top of the braking surface, its about 1.25 inches long (going along the curve of the rim) its maybe a 1/4 inch wide at the widest part. It has a half circle shape with the center of the half circle being the most pushed in. its not pushed in a lot, but noticible at a glance. It looks like I took a big ball peen hammer and hit the rim really hard. (Which I haven't done, nor have I been in an accident, nor do I throw my bike around, really I am a gentle guy when on the road.) It is on the left side of the rim. The other rim that did this started the same and then the dent or folding got bigger, interfereing with the bead of the tire. I am anal about tire pressure 110-120 psi, no brake, 2 sudden flats (rode to a stop no further), flats were from debris in road. Does this help? Thanks for the advice so far. I am just stumped on this, and don't want to keep lacing new rims up if its something wrong with the bike.

Landgolier

Sounds like you might have rolled through some street grates. I'd also contact velocity, they might be able to help you out.

TallRider

I have no idea how this happened, beyond Landgolier's thought. Tell us if you figure anything out.

Michel Gagnon

I have had a similar problem on the rear Velocity Dyad rim on my tandem. The tandem has a fairly light load, since I weigh 170 lb, my stoker weighs 55 lb and my second stoker on trailercycle weighs 45 lb. I also have panniers. However, we have plenty of potholes, so I have to hit a few of them, and even with proper pressure, I bent the rim inside once.

Anyway, to fix the problem I have straightened the rim by going softly with a pair of pliers (after I removed the tire, obviously). Make sure you protect the rim surface beforehand otherwise the pliers will leave marks that would interfere with braking.

So I solved that problem, but I now discover that the rims want to crack in many places and really don't like shocks whatsoever. They remain straight, but show cracks around the valve and nipples. So I will soon replace these rims with Mavic 719 rims which seem to last much longer when riding loaded on uneven surfaces.

DannoXYZ 

Sounds like you hit a big pothole or something that caved in your tyre completely and banged the rim on the ground. You can use small adjustable crescent wrench to grab the middle of the dent, then bend it back outwards. Use calipers to measure rim-width at three other good spots on the rim, take the average and bend the dent back out to that value.