MinnMan

OK, I'm going to show my bike mechanics ignorance here. Kind advice will be appreciated.

Early on a club ride tonight, I hit a big pothole going fast and immediately afterwards I felt increased resistance. Nothing seemed to be terribly wrong, though I did wonder whether a spoke had broken or a rim cracked and how I would know without stopping to inspect (should I have?). Anyway, I completed the ride without incident. It was (for me) a very fast ride, averaging about 21 MPH over 29 miles. I did more wheel sucking than I might have otherwise, in part because my bike now felt just a little slow.

Anyway, after the ride I checked the wheels - there are no broken spokes or rim cracks, but the rear wheel is now out of true, and I'm pretty sure it wasn't before the ride.

How much effect could that have on the bike? Does an out-of-true wheel generate appreciable aerodynamic resistance?

Wogster

Pothole, eh, you probably bent the rim, so that it's rubbing the brake on one side or the other, if the bend is slight then the spokes on one side can be tightened more and loosened slightly on the other side to pull it back to true. An emergency repair is to loosen the brake cable slightly to widen the shoe to rim gap, so that it stops rubbing, but remember that this reduces braking efficiency. This is a temporary stop-gap repair and the wheel should be taken to a shop for inspection and truing.

MinnMan

No, the brake pads aren't touching the rim - that was the first thing I thought of. I will likely take the wheels in to the shop tomorrow.

KillerBeagle

If the pads aren't rubbing, maybe you got a slow leak due to a tube pinch, or the bearings are damaged. I can't think of anything else that would make you feel slower. I don't think the air resistance would change significantly when out of true in a minor way.

BluesDawg

Sounds like it made you go faster.

stapfam

Some one has mentioned it but if the bike was slower after wards- check the bearings. Not the bearings but the axle. Solid axles with nuts have a habit of bending with just normal use and I have come across QR axles that have been bent. Threw the wheel right out of kilter and gave the appearance of bent rim.

And I have seen rims bent so far that they would not turn within the forks- let alone brake blocks. Retruable by my wheel builder but Get him to check for any damaged spokes. Surprising how soon after a "BIG" hit- spokes start breaking.

DGozinya

I hate to use a trite phrase, but "this."

I do have to question the comment that your wheel is wobbly, but yet it isn't touching your brake pads. I, and most other riders I've ever observed, usually have the brakes tightened to within a gnat's-rectumn's-width of touching. If you can have a wobbly wheel and it DOESN'T touch the brake...hmmm.

chasm54

For future reference, if you hit a pothole and immediately afterwards notice something different about the way your bike handles, you need to stop and check it out. Having a wheel out of true isn't necessarily a disaster, but what if the wheel was no longer properly seated in the drop-outs, or you'd cracked a fork, for example? If something is clearly wrong it's best to know what before beginning your next descent, or sprinting...

bradtx

Yes, you should've stopped to see what was making the bike feel different.

Running faster than normal equals more exertion than normal. This might've made the bike feel slow.

Brad

donheff

I still have an old Specialized Crossroads bike that got hit by a car (me backing out of the garage). The front wheel seemed so bent it would have to be trashed but I was able to true it enough that it runs smooth. That was about seven years ago.

oldster

never mind

ericm979

No. No aero difference. It won't slow you down unless the brake pads are rubbing or the tire is rubbing on the frame. BTW that can damage carbon frames and will rub paint off painted frames.

A broken spoke can flip out and wedge between the wheel and frame, damaging a carbon frame or causing the wheel to stop turning suddenly. But I have completed a long road race with a spoke that broke in the first couple miles and been ok- it stayed in place for the race. On rides I stop and twist the broken spoke around another spoke so it won't flap around. Usually that, and opening the quick release, is enough to finish the ride. A few times I have had to do a quick field retruing so the tire would not rub on the frame.

t4mv

Technically, I think a gnat's-rectum's-width gap between rim and pad is a little too close because should you descend a long hill w/ a fair amount of braking, the hands will be sure to let you know. Your point is well taken though; even if there's enough wobble to hit the pad(s), just rotate the QR until the rim clears.

DGozinya

LOL... I am a little different in that I don't have a lot of hills around me and more importantly, my hands are the size of canned hams, so reach and such is never a problem. Just like in my automobiles, I like a brake that is "firm" without a lot of pedal/lever travel.

OldsCOOL

Agreed. I'd look into tire pressure immediately.

This is why I carry a Park Tool spoke wrench in my seat bag. Havent had to use it during rides but it's there in case. I hate it when rims are out of true....especially when so much time is spent staring at the front one. Oh wait, that's why we hit potholes

chinarider

I did a century last month (report here: https://www.bikeforums.net/showthread...ort?highlight=) and due to crash @ 10 mile mark, did the rest with a wobbly front wheel. Had to flip the brake QR to prevent rubbing on the brake. Otherwise, I didn't think it slowed me down at all.

stapfam

5 of us out on a ride this morning and we started from my house. I maintain my bike and one other but as one rider arrived I heard an intermittent brake noise. Checked his back wheel and it was out of true. 2 minutes later and it was true. Son-in-Law arrived and he said his rim was bent so passed him the spoke tool. 5th turned up and I decided to check his wheels as a precaution. No problem. He had just put his wheels in for an annual service and had 5 spokes replaced and new bearings.

Wheels go out of true very easily if you are offroad or hit potholes. Luckily a little bit of out of true will not be noticed but it does get worse if not attended to.

Bob Ross

+1
Coincidentally, on yesterday's ride my wife's Mavic Ksyrium Elite popped a spoke during a JRA and her wheel immediately went so out-of-true that it almost caused the bike to stop on teh proverbial dime. Opening the brake caliper's quick release did nothing to alleviate the problem; we had to loosen the brake cable and take out all the slack to get the pads far enough away from the rim so she could ride to the bike shop.**

Ordinarily my pads are a 2 or 3 credit cards' width away from the rims. I want the full range of modulation available.



** Incidentally, the oft-touted and seemingly apochryphal advice to avoid proprietary/exotic wheels due to the unliklihood of finding replacement parts when out on the road proved true yesterday. We were lucky to find a bike shop 3 miles away from where teh spoke popped, but despite having an enormous assortment of spare spokes in their inventory they did not have any exact replacements for a Mavic Ksyrium Elite. The shop mechanic actually had to make a spoke for my wife's wheel! He took a stock (non-proprietary) spoke, cut the end off, and tapped (threaded?) a new end so it would fit a Mavic nipple. Really impressive McGyvering...especially for a Sunday afternoon in the middle of nowhere. Guy was a real life-saver.

No more proprietary wheels for us. Conventional round spokes, please...and plenty of them.