Wkend_Warrior

I starting to notice when I descend with speed greater than 40mph that I feel bumpy from my rear wheel. It kinda feel like there is a pebble on my tries. Now, if I slow down below 40 than I wouldn't be able to feel that.

Question: Is that got to do with the quality of the tires? or Is the wheel not true in the axile direction? If so, I'm can't tell with my untrained eyes. Btw, I only ridden less than 600mi on this wheelsets.

here is my spec.

WHEELS: Bontrager Race Lite Wheelsystem
TYRES: Bontrager Race X Lite 700x23
On a 07 Madone 5.2SL and i usually pump my front tires at 95psi and rear at 105-110psi.

Thanks in advance.

Spin Cycle

I had the same symptoms - turned out that my wheel was out of round, due to an encounter with a pothole. Used the opportunity to get some new wheels

waterrockets 

Possibly out of round wheel, possibly poorly seated tire. Pull the tire off, mount the wheel, and spin it fast. See if it hops up and down much when the bike is not moving (don't let the bike move during this test). Then, put your tire on and see if it moves any more or the same. If it moves more, it's the tire or seating. If it moves the same, then the wheel is out of round.

Wkend_Warrior

thanks guys.

I will try that out this wkend.

thanks again.

Wkend_Warrior

Waterrockets,
Thanks for your suggestion frist of all, do you have a suggestion of what to use to gauge the movement of the wheel while spinning? I can use the break pads to measure the wheels trueness [sp]. what would you suggest I should use to reference the wheel if it is round?

If anyone can chimmy up, I would appreciate verymuch.

Thanks.

Spin Cycle

Same way - watch how the space between the rim and the brake pads changes as the wheel rotates.

waterrockets 

Clothes pins work great. Just clamp onto your seat stay or a fork blade. If that isn't working for you, try rubber-banding a pencil on there.

Wkend_Warrior

thank you very much. I'll give it a try.