Ducati Monster Forum

Moto Board => Tech => Topic started by: Privateer on February 23, 2012, 06:28:51 AM

Title: unbalanced tire?
Post by: Privateer on February 23, 2012, 06:28:51 AM
i recently had new tires put on and I've noticed a weird vibration when I get up to 45-50mph.  I haven't been able to isolate if it's the bike or the road, if it's front or back, or if I'm just imaging it.

I thought maybe it was an unbalanced wheel, but I don't know what that behaves like or feels like. 

so what does an unbalanced wheel feel like?
Title: Re: unbalanced tire?
Post by: zooom on February 23, 2012, 06:36:28 AM
check tire pressure and when was the last time the steering head bearing was checked/serviced/replaced?
Title: Re: unbalanced tire?
Post by: Speeddog on February 23, 2012, 08:37:26 AM
Put the bike up on stands and spin the wheels.
If you need to, push the brake pads back a bit so the wheel will spin longer.

Check the tires for lumps, and that they're fully and evenly seated on the rim.

The actual out-of-round at the tread is often a millemeter or thereabouts.

Do the wheels have balance weights on them, and how much?



Title: Re: unbalanced tire?
Post by: Privateer on February 23, 2012, 05:23:02 PM
Quote from: zooom on February 23, 2012, 06:36:28 AM
check tire pressure and when was the last time the steering head bearing was checked/serviced/replaced?
front was 34, which is a little higher than I normally put it, so I let it down to 31.
Rear was 33, which is where I normally have it.

steering head would've been serviced about 24k miles ago.

Quote from: Speeddog on February 23, 2012, 08:37:26 AM
Put the bike up on stands and spin the wheels.
If you need to, push the brake pads back a bit so the wheel will spin longer.

Check the tires for lumps, and that they're fully and evenly seated on the rim.

The actual out-of-round at the tread is often a millemeter or thereabouts.

Do the wheels have balance weights on them, and how much?


tires looked normally seated and round when I spun them with a make shift feeler gauage.

weights, front is 3/4 oz, rear is 1oz.
Title: Re: unbalanced tire?
Post by: zooom on February 24, 2012, 05:08:08 AM
Quote from: Privateer on February 23, 2012, 05:23:02 PM
steering head would've been serviced about 24k miles ago.

ding!....or at least, that'd be where I would be headed to 1st anyway...you can try tightening the steering head top bolt down just a smidge and then go order a new set of steering head bearings from allballsracing.com or any other bearing distributor....
Title: Re: unbalanced tire?
Post by: Howie on February 24, 2012, 05:47:36 AM
Hmmm...no vibration, install new tires, vibration pops up.  I would expect tire balance or wheel bearings.
Title: Re: unbalanced tire?
Post by: zooom on February 24, 2012, 06:15:19 AM
ooops...I kinda glazed over/past the "new tire installed" part....could be worth just generally rechecking all the bolts oriented around taking the wheel off in case something isn't quite torqued enough...not sure what if any of these would result in a wobble...but I guess anything is possible and worth checking at this point...
Title: Re: unbalanced tire?
Post by: ducatiz on February 24, 2012, 07:06:58 AM
Quote from: howie on February 24, 2012, 05:47:36 AM
Hmmm...no vibration, install new tires, vibration pops up.  I would expect tire balance or wheel bearings.

there you go with your damn "logic" and "reading the whole post" crap again
Title: Re: unbalanced tire?
Post by: Privateer on February 24, 2012, 07:16:02 PM
well yeah, I did ask what an unbalanced wheel feels like.  I don't know if what I'm feeling now is that or something else.

I checked the torque and alignment of the rear and it all looked good.  I'll check the front in the morning.
Title: Re: unbalanced tire?
Post by: monsterdan on February 25, 2012, 08:39:32 AM
Unbalanced tyres can make a bike feel weird, just depends how sensitive you are to it, and how familiar with the road (knowing where all bumps are).  I had an issue that took weeks to solve when I put some chunky alloy valve caps on. I never noticed when in commuting in traffic, as too much to concentrate on, but come weekend or late nights i could not figure out what the issue was with the bike feeling just weird.  After about two weeks of head scratching, bolt torquing, tyre pressure checking, i put the old plastic ones on, and the vibrations went away.  So, worth getting them checked of your not happy.
Title: Re: unbalanced tire?
Post by: Howie on February 25, 2012, 09:15:22 AM
Usually vibration at a particular speed range is wheel balance or an out of round wheel, up and down vibration static and side to side dynamic.