canklecat

I skidded on a patch of gravel during a routine turn this week. I didn't fall and was traveling maybe 12-15 mph. The bike skidded right, I caught myself with one foot down and fishtailed slightly the other direction. The snapping two-way skid warped the single wall rim on the rear wheel (Araya PX-45).

Here's how it looked from my helmet cam video:

I managed to straighten it enough to ride home slowly, and the LBS mechanic whanged it back into shape. There's only a very slight wobble now.

I'll probably replace it with a double wall rim soon anyway. But I'm wondering whether it's worth salvaging, maybe for another bike, and whether it's safe to continue riding for now. No stunts, nothing fancy or fast, I usually average 12 mph riding decent pavement and the paved part of the MUP.

And after I replace the wheel (depends on my budget this month), I'll probably use the original hub to build my own budget wheel. Just a challenge I want to tackle. I need to learn to do more of this stuff myself. Can't afford to pay the LBS every time something goes wrong, although they do good work at reasonable prices.

Bill Kapaun

If you didn't hit anything, your spoke tensions had to be very uneven.
Possibly to correct for a previously bent rim.
A "good" rim wouldn't require whacking.

canklecat

Could be. I bought the bike used a couple of weeks ago. I checked the spoke tension on both wheels with my fingers, and didn't notice any significant differences.

Some spokes were definitely loose after the skid and rim was warped. I don't have a spoke tool yet and am not sure I wouldn't have made things worse by fiddling with it on the roadside. That's one reason I want to learn to do this stuff myself. I'd like to ride a self-supported tour someday, so I need to learn more basic mechanics.

fietsbob

Maybe you can slam the rim flat again, with Force?

canklecat

Already done. Per my initial post: "...the LBS mechanic whanged it back into shape."

I'm wanting to know whether it's safe to continue riding -- cautiously, and for no more than a month -- after minimizing the warp, checking the spokes, etc. I don't recall hearing reports of any catastrophic failures from repairing stuff like this, but maybe these did occur and there were no survivors to tell the tale.

Retro Grouch 

If the wheel looks kind of like a figure 8, that slamming the rim against something to spring it back will probably work.

If the rim looks like it's just out of wack in one area, you might be able to bend it back (kinda) straight against a post or workbench edge or something like that.

A single wall rim is pretty low end. If it was my bike I'd plan on replacing it.

cny-bikeman

The factor as to whether a rim is stable is spoke tension and very little else, unless it is cracked. If sufficient and fairly even spoke tension can be achieved after physically straightening the rim then it's perfectly safe.

Bezalel

I can't see how that slide could bend a wheel in good condition. I'd say to remove all the tension and see how out of shape the rim is in. Then you can make a decision whether to just retension, bend and retension, replace the rim and retension, or replace the entire wheel.

dabac

It's usually not the slide, but the sudden stop. Coming off a slippery patch and onto good traction can be similar to skidding into a curb.

dabac

I've manually straightened, pulled out low spots and fixed pulled through spokes by replacing spokes with slightly longer and adding washers on the nipples on several rims before degrading them to beater use. Never had any issues.

andr0id

It's safe enough. The annoying thing about warped or taco'd rims is that you have to use uneven spoke tension to make them round again. This usually results in spokes starting to break after a few months. Depends on your weight and how you ride them though. Could be fine for a while.

bradtx

canklecat, The wheel is very likely safe to ride as long a brake performance has not been degraded. If it is safe to ride for a month, it may be safe for many more. For your own peace of mind replace as soon as possible. A good option is to have your bike mechanic reuse the current hub and build with a new rim and spokes. A new hand built wheel for not much more than a budget wheel bought online. You may also want to have the mechanic check your other wheel as I don't think a single walled rim was the root cause of the failure.

Brad

WizardOfBoz

Canklecat, your politeness to the nice concerned driver, and her concern, remind me of one reason I liked Texas a lot.

Hook 'em. Good luck with your wheel.

cny-bikeman

No, uneven spoke tension means the rim was not physically straightened sufficiently before truing, and warped/taco'ed rims are not out of round unless that has not been done. When I was an active mechanic I often repaired such wheels without subsequent problems.

ThermionicScott 

It's possible that the weight put onto it while tilted over caused it to collapse into a taco shape. It's a known phenomenon.

canklecat

Thanks, all. I think I'm going to replace the rear wheel and save the original to practice on. I really need to do more of my own wrenching, especially because I'm interested in self-supported touring someday. Now I just need to settle on a basic tool kit. Too many choices now besides the Nashbar and Park.

I see from the Araya website the original PX-45 rim was rated "light duty". The bike came with front and rear racks and I'll feel more confident in lugging loads if the rear at least is a double wall rim.

Same thing happened to the single wall Alex Z1000 rear rim on my other bike, after some gravel and off-road rides. No tricks or jumps, but some rough terrain including washboard ruts and unpredictable sandy washouts with some sideways slides. Spoke snapped and the wheel warped. The LBS replaced it with a Weinmann Zac 19, with heavier gauge spokes and hub. Since I occasionally haul 40+ lbs of groceries and whatnot on the rear rack of that bike, I like feeling more confident in the replacement wheel.

In this case, I think the two-way snap may have contributed to the warp. It didn't show on the helmet cam, but the rear end fishtailed right (counter-clockwise), then snapped left when I put my left foot down and turned the bar in the direction of the skid. It all happened so quickly I'm still surprised I didn't hit the ground. I weigh 160, probably not enough to be a big factor in the incident.

canklecat

I've found folks to be uncommonly friendly in that part of Texas, even by Texas standards. At least two other folks have stopped to offer assistance over the past year in that same little town when they saw me stopped along the road. One of 'em gave me a lift home when I had my first flat tire and had forgotten my pump.

A few weeks later the same fellow offered me a ride when he saw me in the rain, but I politely declined because I was specifically testing out a new set of puncture resistant tires in the rain to get a feel for the handling. I still stop and visit with him occasionally when I'm passing through if he's out working in the yard. Good fellow.

I try to return the favor or pay it forward whenever possible. I've stopped a few times to offer assistance to other cyclists. On a few group rides I've noticed a tendency for so many riders to stop and offer help that the cyclist with the mechanical or maintenance issues could sit on the roadside while other cyclists fix his/her bike!

Funny ol' place, Texas. Every time I think I've got it figured out, it stops, does a little dance and magic act, and defies my expectations. Not necessarily always the way I'd prefer, but everything seems to work itself out.

canklecat

Well, I've ridden the Univega as-is for almost another week, including a 40 mile group ride over the weekend. No problems. I may hold off a while on replacing the rim.

Meanwhile I bought a basic tool kit, a Venzo brand that appears to be pretty good. Had the stuff I needed to properly adjust the center pull cantilever brakes, although I need to replace the pads -- they're pretty much hopeless. Braking is only a suggestion with these hardened old Shimano pads.

So I'll study some tutorials and take a whack at tuning the rims myself. The rear wheel that was warped is now straighter than the front, which has a slight wobble.

If I screw it up I'll replace 'em with some affordable machine built wheels. The LBS put a pre-built Weinmann Zac-19 wheel on my hybrid a few months ago when I warped the original rear single wall wheel. Good stout rims with sturdy spokes, basic hub. Good enough for my needs, and if I purchase directly and install 'em myself, I can afford to replace both for the cost of one through the LBS.