new tires, unstable?

[GHill762]

upgraded the IRC's on my 300 to pirelli DR2's in 150/60 and 120/60.. at the same time had the steering bearing replaced. now, I find that at in-town speeds, it's hard to hold a straight line (cruising down a straight road). Is it because these new tires are so much more round (old tires had a squared off center)? or did they mess something up during install (forks out of alignment, overtightened axles, etc)?

did anyone else notice this when going to a DR2 in 120 & 150? driving straight it feels like trying to stand on a bowling ball, or stacking marbles.. like it doesn't want to stay perfectly upright, it shifts back and forth (very slightly, but enough to be annoying).. if it's just the tires, I'm sure I'll have a nice squared off center again in no time, but if they boogered something up I want to make it right..

Thanks,
Garrett

[tooblekain]

Originally Posted by GHill762

upgraded the IRC's on my 300 to pirelli DR2's in 150/60 and 120/60.. at the same time had the steering bearing replaced. now, I find that at in-town speeds, it's hard to hold a straight line (cruising down a straight road). Is it because these new tires are so much more round (old tires had a squared off center)? or did they mess something up during install (forks out of alignment, overtightened axles, etc)?

did anyone else notice this when going to a DR2 in 120 & 150? driving straight it feels like trying to stand on a bowling ball, or stacking marbles.. like it doesn't want to stay perfectly upright, it shifts back and forth (very slightly, but enough to be annoying).. if it's just the tires, I'm sure I'll have a nice squared off center again in no time, but if they boogered something up I want to make it right..

Thanks,
Garrett

Its your steering bearings...They were tightened it down way too tight. I had the same thing happen trackside and had the exact feelings you described. It was like fighting the bike to just not crash. Tighteing down the steering bearings is tricky. It can't be too loose or too tight. I spent my whole trackday trying to fix this problem. Too loose and under brarking the front end would shake violently back and forth.

[GHill762]

Originally Posted by tooblekain

Its your steering bearings...They were tightened it down way too tight. I had the same thing happen trackside and had the exact feelings you described. It was like fighting the bike to just not crash. Tighteing down the steering bearings is tricky. It can't be too loose or too tight. I spent my whole trackday trying to fix this problem. Too loose and under brarking the front end would shake violently back and forth.

I don't get any front end wobble, shaking, etc.. the front end is VERY smooth now with the tapered roller bearings.. it's more of a balance issue during in-town cruising.. like the whole bike wants to lean rather than stay perfectly upright (this is very minor, but annoying).. when I let go of the bars there is no wobble or shake at all (like there was prior to the bearing replacement)..

but you're saying it's the bearings cranked too tight? is it not allowing the bike to cope with changes in the road? what do I do to correct this? do I just loosen the center steering stem nut?

[GHill762]

If I am looking at the manual correctly, it looks like 15 ft-lbs torque on the steering head nut. with tapered roller bearins, will that change? do I just need to play with it until it feels good?

[tooblekain]

Originally Posted by GHill762

I don't get any front end wobble, shaking, etc.. the front end is VERY smooth now with the tapered roller bearings.. it's more of a balance issue during in-town cruising.. like the whole bike wants to lean rather than stay perfectly upright (this is very minor, but annoying).. when I let go of the bars there is no wobble or shake at all (like there was prior to the bearing replacement)..

but you're saying it's the bearings cranked too tight? is it not allowing the bike to cope with changes in the road? what do I do to correct this? do I just loosen the center steering stem nut?

Im not going to completely rule out the possibility of it being too tight. You need to loosen the nut where you need spanner wrench a tad. You might have to remove your top triple to access it.

Maybe check for wheel balance. Might want to check wheel alignment with each other too. Make sure your chain tensioners are equidistant on both sides and that you have proper chain tension.

[tooblekain]

Originally Posted by GHill762

If I am looking at the manual correctly, it looks like 15 ft-lbs torque on the steering head nut. with tapered roller bearins, will that change? do I just need to play with it until it feels good?

That torque value may be different now with tapered roller bearings. I know for the steering stem and head bearings, its about getting it not too loose or too tight. That's for all bikes across the board.

[GHill762]

Originally Posted by tooblekain

Im not going to completely rule out the possibility of it being too tight. You need to loosen the nut where you need spanner wrench a tad. You might have to remove your top triple to access it.

Maybe check for wheel balance. Might want to check wheel alignment with each other too. Make sure your chain tensioners are equidistant on both sides and that you have proper chain tension.

could you elaborate on the section I bolded/underlined?

wheel balance would cause vibration issues right? it's not vibrating, it's super smooth..

my chain is perfect now, they had it too tight from the dealer, but I adjusted it and changed to a 15t front so rear wheel has been completely re-aligned..

I'll have to check wheel alignment (to each other).. not sure on that one..

[tooblekain]

THis is going off knowledge based on my Ninja 250, so Im not sure if the steering stem nuts are the same for the 300

Wheel balance can cause "speed wobbles"...on the track you may feel a wobble at certain speeds and then goes away if outside of the speed wobble parameters. You can double check your wheel balance by taking them off and using a static balancer to see if it's perfectly balance. A perfect balanced wheel will stay put not matter what orientation the wheel is on.

When you adjusted your chain did you make sure that both chain adjusters on each side of the swingarm are equidistant?

The best way to check for wheel alignment is the string method.

[rojoracing53]

Can you currently(not when you were 10 years old) ride a bicycle with no hands smoothly?

[krolinked]

Sounds like your just getting used to the new tires. Also they are much rounder since they are new, it feels like riding on a groove right? And your either on one side or the other of the groove but never perfectly on it.

[jkv45]

Sounds like the steering head bearing are too tight to me too.

I've heard similar comments from others that have replaced the ball bearings with tapered bearings, and found they over-tightened them.

It's not the top nut, it's the collar under the top triple that you need to loosen - if that is the problem.

[alex.s]

if you wanna go straight, buy a harley!

[CC Cowboy]

I haven't seen a straight Harley rider on years.

[GHill762]

Originally Posted by krolinked

Sounds like your just getting used to the new tires. Also they are much rounder since they are new, it feels like riding on a groove right? And your either on one side or the other of the groove but never perfectly on it.

I THINK this is all it is, since it's getting better not worse. And it's very faint anyway. If it continues after another couple hundred miles I'll look into it more.

[GHill762]

Originally Posted by jkv45

Sounds like the steering head bearing are too tight to me too.

I've heard similar comments from others that have replaced the ball bearings with tapered bearings, and found they over-tightened them.

It's not the top nut, it's the collar under the top triple that you need to loosen - if that is the problem.

Thanks, if it continues after a couple hundred more miles I'll give this a try.

[GHill762]

Originally Posted by alex.s

if you wanna go straight, buy a harley!

Lol I don't WANT to go straight but I can't zig zag to work




Thanks everyone for the help. I think it's just new, very round tires.. We'll see.

Thanks,
Garrett