Front end shake between 80-95km/hr

[jefflthomas]

Check your rear wheel alignment (tracking), bearings, tire wear and balance. An oscillation in the rear will cause the front to feedback.

damaged the carcass of a rear GP208 on a rocky cottage road & the front started shaking like hell when i got back on the highway

[stangn99]

Thanks guys,
I'm going to check the tire. If it checks in OK, i'm just going to take it to the shop. After doing some more research, it seems like its highly possible that its the tires. If all else fails, I'll take it to a shop and have it professionally looked at.

[promac]

Front end shake can have many contributing factors that compound the effect. Wind buffeting and turbulence, bumps, more speed and/or "death grip" could result in a violent tank slapper. After you resolve most of the issues, a decent steering damper is good insurance.

[stangn99]

Ok..

I got home and ran my hand along the front tire - no abnormal grooves, or anything uneven. The wear felt and looks completely normal and even.

- I put the rear on a stand, and lifted the front.
- Removed calipers
- Got helper to hold the handle bar while I shook the tire from left to right and back and forth, and also spun the tire by hand.

Observations:
- There is absolutely no play in the wheel (nice and tight)
- There is no play in the handlebar (nice and tight)
- There was no strange noises when spinning the wheel (no scrape, whrrr, creaks or anything)
- The wheel spun freely for a VERY long time before coming to a stop


What I did notice, was a VERY VERY slight wobble in the tire when looking down towards the ground.

Did I miss any tests? Should I try something else while the bike is still up with calipers off?

[bocutter]

- The wheel spun freely for a VERY long time before coming to a stop

Mark the tire (chalk or small piece of tape). Spin gently it a few times. If it always stops at the same place it needs balancing (static test).

[stangn99]

Mark the tire (chalk or small piece of tape). Spin gently it a few times. If it always stops at the same place it needs balancing (static test).

Oh wow.. that's really smart.
I'll give this a try.

How to they balance motorcycle wheels? Is there a machine for it, like for car wheels?

[FriendlyFoe]

it's the same machine but all the machine does is a computerized version of a static test. Yes if you pull your wheels off (as i said in an earlier post) a shop will probably check balance on both of them for 20 bucks

[stangn99]

Did the test...looks like all I need is a balance.

I'm going to get new tires anyway. It doesn't make sense to balance these tires, as their only good for another season.

Question:
Stock tire size is:

Front: 120/60/17
Rear: 160/60/17


What would happen if I run 120/70/17 for the front instead?

[jefflthomas]

What would happen if I run 120/70/17 for the front instead?

don't know what you're riding but you may not have a safe front fender clearance

[stangn99]

don't know what you're riding but you may not have a safe front fender clearance

Is the 70 the height of the tire?

[jefflthomas]

Is the 70 the height of the tire?

i think technically it's the width of the sidewall...but yes

[slowbird]

Stick to the manufacturer recommended tire sizes for your bike.

[stangn99]

i think technically it's the width of the sidewall...but yes

Thank you.

Alright...looks like i'm going to be doing some tire shopping.

[bocutter]

It doesn't make sense to balance these tires, as their only good for another season.

It doesn't take long to do it yourself. I got some weights from Glen @ Flying Squirrel when I picked up a new chain. Rear tire took 28gm and about 1/2 hr.

[kneedragger88]

It doesn't take long to do it yourself. I got some weights from Glen @ Flying Squirrel when I picked up a new chain. Rear tire took 28gm and about 1/2 hr.

You cannot balance a rear wheel. Laws of physics make it that way.
You hang your weights on the wheel on your balancer then you slap cushdrive, sprocket carrier, at least 5 12mm nuts and bolts, not to mention a chain that doesnt hit the same spot on the wheel every revolution of the wheel on at install. Making the balance redundant.
Now tell me how your 28g of weights counteract the 15lbs of unbalanced weight your then going to hang on the wheel and spin?
Front is different, where all spinning parts are on the wheel when it is on the balancer.
Unless you have a shaft drive its impossible to balance a rear wheel.
My personal favorite is when a rider gets his wheels balanced attaches those lightup valve caps. Generally they weigh more than the weights.
I have had this argument with people for years including tire vendors at the track. Yet to have anyone convince me otherwise. Wanna give it a shot?

[stangn99]

It doesn't take long to do it yourself. I got some weights from Glen @ Flying Squirrel when I picked up a new chain. Rear tire took 28gm and about 1/2 hr.

Yes, I've bought from Glen before. He's a great guy. He hooked up my dad too.

I wouldn't mind trying it myself actually.

Question: Does the bike have to be perfectly balance on the stand to do this? When I spun the front wheel, the marked spot seemed to always stop at the same position.

I just thought about it right now, and was wondering if the slight include of my driveway would contribute to this.

Does the bike have to be off the ground and level to the ground 100% band on to achieve a good balance?

[jefflthomas]

You cannot balance a rear wheel. Laws of physics make it that way.
You hang your weights on the wheel on your balancer then you slap cushdrive, sprocket carrier, at least 5 12mm nuts and bolts, not to mention a chain that doesnt hit the same spot on the wheel every revolution of the wheel on at install. Making the balance redundant.
Now tell me how your 28g of weights counteract the 15lbs of unbalanced weight your then going to hang on the wheel and spin?
Front is different, where all spinning parts are on the wheel when it is on the balancer.
Unless you have a shaft drive its impossible to balance a rear wheel.
My personal favorite is when a rider gets his wheels balanced attaches those lightup valve caps. Generally they weigh more than the weights.
I have had this argument with people for years including tire vendors at the track. Yet to have anyone convince me otherwise. Wanna give it a shot?

picked up a static balancer a few years back

see your point but i'll balance what i can

[frekeyguy]

picked up a static balancer a few years back

see your point but i'll balance what i can

1/2 hour to balance a tire = 1/2 that im not riding.

its not necessary, but you can do it anyways.

im sure if i rip off your weights from your rear, you wont notice it

[jefflthomas]

takes me about 5 minutes to balance a tire mate

[stangn99]

takes me about 5 minutes to balance a tire mate

Where did you get the static tire balancer from?