AAARRGGHH!! (tyre / tire rotation)

OK, I know I was supposed to rotate my tyre/cranks before the tyre was almost worn out, but I didn’t. So now, even at medium speeds, I get this really annoying bouncing up and down thing going. Oh well, I needed a new tyre anyway. Duro Leopard 24x3" at 27 psi for the curious. I’ll certainly be rotating my new tyre.

haha, one of my tires has this problem also. It almost throws you off! YOu are bounceing along…boing, boing, boing! The tires get worn out fairly quick, so yeah, rotate them…

I rotate my tire every time I ride.*

    • has this joke been done before?

:slight_smile: You know, as I typed my original message, I thought someone would reply thus. I almost added “hey - no rotation jokes”. I can not respond with certainty, but I think this joke has probably been done before. But hey, I still smiled.

not sure if you know but don’t rotate your cranks… if they are press fit it stops working as well

Er… Pardon? I do not understand what you mean. What are “press fit” cranks? FYI, the cranks in question are cheap aluminium prowheel cranks (square taper) on a UDC hub.

Cheerz.

I really need to do that I have one bald spot on mine It doesnt effect anything yet though.

square taper (including what you have) and most splined cranks are press fit. basically the axel and cranks are tapered. when you tighten them you actually pull them together hence the “press fit”
the other cranks are pinch bolt and just slide right on and off. one bolt pulls the crank (where it attatches to the crank) tight to the axel and one bolt pulls the crank into the center of the wheel.

Is this really a problem? With square taper (which needs a bit more torque than ISIS - square has more taper), the crank material is reasonably soft, and I tighten the bolts as hard as I can (a largeish percentage of my body weight) with a 6 inch lever. This equates to about 60 foot pounds. Plenty enough to deform the soft crank material. I think the bolts fail at around 100 foot pounds. I might start using medium loctite, as the bolts need occasional tightening, even after weeks of riding, and several tune ups.

Thoughts?

Well exactly, you want to avoid removing and refitting square taper cranks as much as possible because you can only deform the taper so much before they won’t fit tightly anymore especially for aluminium cranks). Non-taper splines move around a little causing spline wear (for instance new profiles are very tough to get off the axle initially, but after riding on them alot will slide off easily) so it’s worth rotating them to even the wear out, but for square tapers rotating will do more damage than good. Just spin the tyre on the rim if your riding puts a flat spot on it.

Ok, this does make sense I see. But, does this apply to ISIS though? With less taper angle and splines, and somewhat lower torque on the crank bolt, doesn’t that mean you can pull the cranks on and off more times without damaging them too much?

you can yes, but you dont wanna be taking them off once a day just for th esaek of it.

What are you doing up this late? Tomorrows a school day!!

Obligitory thread bit: Hmmm. Can’t afford a new tyre for a while, so I am thinking of attacking my unevenly worn tyre with a stanley knife to even it up…

im about to go to bed. been busy talking, and not doing study.

im tired.

oh well school is boring whether im awake or asleep through it.

night.

I would worry much less about ISIS, you wouldn’t expect splined cranks to deform noticeably when they’re tightened up even if they’re on a taper like ISIS or the KH/Onza splines. While I avoid removing the square taper cranks on my 36" unless absaloutely necessary I’m perfectly happy to rotate my KH/Onza cranks on my muni and trials uni. Incidentally as removing sqaure taper cranks requires large forces in the tool you’re likely to damage the threads in the crank and the end of the hub that the puller tool presses on. I’ve had to have my coker hub threads re-tapped due to damage from a crank puller tool before, and seen the thread in a crank ripped clean out. By comparison splines seem to take less force (except profiles), and some have clever integrated self-pulling mechanisms that make it a doddle.

Sigh. You are right on the money with the sqaure taper removal damage syndrome. I found that the crank remover deformed the top of the hub thread slightly. This made it extremely difficult to re-insert the crank bolts without cross threading. I had to carefully dress the hub thread with a file to get them to go in again. At the time, I was wishing I had the right tap for the hub. I would have used it to clear out the top of the thread.

Thanks to all for the good advice :slight_smile:

hahaha! I just attacked my tyre with a utility knife, sawing of the knobs where they were too high, and the crazy bouncing is largely sorted out! Ok, I still need a new tyre, but it’ll get me by for few weeks. :slight_smile:

uhh
lol
pinch bolts wear out too!!
my axle has about a 1/32 ridge all the way around where the cranks hit the axle’

but that might be from ahem… i don’t know what that could possibly be from… ahemm