Hi everybody!

I was out biking the other evening, cruising along at a good pace, when someone did a U turn, may or may not have seen me but I did have to lock up the brakes and do a nice sideways skid, didn't lose it though...

Anyway, I had my bike up on a stand adjusting the gears, when I noticed the wheels, both front and rear, seem to be out of true. I never noticed this before and wondering if the hard braking with a skid could've caused it. I ride in the city, not really smooth streets, I do need to ride over speed bumps and small cracks here and there.

Thanks, Rick

Skidding wouldn't do that. I assume that is a cheaper bike with factory built wheels and over the life of the bike you never tensioned / trued the wheel. Even expensive hand-built bikes can go out of true over time.

Re true and ride again. Just plug some spokes and hear how they sound differently, means they are tensioned differently.

A very effective way of getting a rear wheel out of true is doing a skid that's suddenly stopped. Skidding into a curb is near-guaranteed wheel misery.
Fronts rarely skid, so are generally safe.

Sure the skid could have helped any out of true happen but any other large force could too as well as mere spoke settling in can. So my answer is "sure, but".


Since the skid put the wheel a bit sideways it saw more side force then usual. Only way to really know would have been to document the wheel just before the skid and then right after. Otherwise too many other real life stuff can happen that also can contribute. Andy.

Thanks for the replies!

Yeah, I visually check wheels (700x32's) for true almost daily...

That day I was running at a lower air pressure than normal, instead of @80psi I was at @60psi. I was going for that "softer" ride. I think the lower pressure and sideways skid knocked it out. Front wheel stopped mostly straight, the rear skid sideways almost parallel to front. It's not so bad that any brake pads rub but noticeable.

Just surprised that could happen but I did read lower pressure might cause it...

Thanks!!!

this could become an interesting physics thread....(or one where we end up name-calling each other...)

If the wheel doesn't skid it it experiences sideway force up to the static friction force available. If the wheel skids, it experiences force up to the sliding friction, which is always much less than static friction. that is why once you skid, you don't stop skidding before you release the brakes or run out of speed. also why ABS in cars helps since with skidding tires brake path is longer.

Unless you skidded against something (a curb etc.) i'd say the wheel wasn't properly tensioned / trued. Or you skidded sidewyas and the wheel got a rougher (more friction) spot and stopped skidding and the momentum bent the wheel.

Best way to answer that question is repeat the process and set up slow-motion cameras all around so we can evaluate

Air pressure and rim trueness is not a direct connection, other then overwhelming the tire/pressure with an impact (the pinch flat) to such a degree that the rim also get's deformed (rim blimps). Side to side forces happen regardless of tire pressure levels. Andy

Hopefully SMIDSY, "Sorry Mate I Did Not See You", applies rather than someone having a contract out on you. Since it has happened and you are OK I guess you get to fix what may have been there before or what happened as a result of it. I guess there may be a question about 'liability' if you made contact or otherwise.

Reminds me of the time, memory probably fails me since it was a long long time ago,

I was going home from College, also at a good pace, and someone decided to drive their car out of an underground car park in front of me. I almost stopped the bike but the handlebars got turned for me by the final impact with his front wing, or I may have flinched, and I ended up rolling over his hood landing on my feet on the other side. I go back and pick up the bike, tell him I am OK and pedal off. I cannot say for certain that I did not see it coming when it presented itself and reacted subliminally.

Lots of wheel threads this weekend...

If the wheels are out of true, you've probably got problems with (lack of) spoke tension, uneven tension, and probably stress relief. IF there's a good wheel mechanic locally, take the bike to him, explain the problem, and let him fix it for you. Otherwise (the more likely case), prepare to learn how to (re)build bike wheels yourself.