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Discussion Starter · #41 ·
Mr. rcannon409, if you could get a 19" knobby to seal on a 17" wheel you are indeed a miracle mechanic.
i think you missed his point
i dont think he was saying that he could actually mount a.....never mind
 

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Yea, just havign fun...I dont think it could be done, could it?

I do remember trying to put a 17 on an 18 inch rim. We were kids.....
 

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with a few basic tools its not bad at all to swap the tires out.
i'm not trying to say you're wrong or anything negative here.
Yeah, but my friend has a professional tire changer in his garage and does it in about 5 minutes and only charges $10. It's good to have friends who do so many track days that they buy their own tire machine to save on tire changes!
 

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I've done enough to where I dont think it takes me 5 min with irons. Breaking the bead is the tough part.

Oh, but mentally, I dont think I'll ever adjust to the sound of a bead seating. That sound sends chills through my arms.

I accidentally exploded a 20 inch bicycle tire. The backside had crept of the rim, and I was not paying attention. I was using the compressor..I saw the tube growing, and that was that. It might have been 20lbs..maybe, but my ears rang for 30 minutes afterwards.
 

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i noticed that when i replace a tire, even when the indicators are about to come through, is noticeably flimsy.
Yeah, I was shocked at how thin a used tire feels in the middle. You can easily indent it with a thumb while it's still on the wheel. It's clearly only about 1/8" thick and has very little puncture resistance.
 

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Yea, just havign fun...I dont think it could be done, could it?

I do remember trying to put a 17 on an 18 inch rim. We were kids.....
Really, I assumed you were dead serious. :poke:

The reality is that I'm pleased and impressed with your offer to help and if I ever make that dumb mistake again I'll take you up on it.
 

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Oh, we coudl have done great things, that day..had we only known!

I did picture you, motoring away, that worn dunlop 756rr thumping with every rotation....but, we'd have balanced it. I saved oen of those. They were the closest offroad "works" lever tire released to the public. SOFT, but sticky like superglue.
 

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I meant to post this the other day, but forgot.

I believe it is an incorrect assumption to assume that uneven tire wear near the end of a tires life is caused by balance.

Was it still balanced when it was near the end?

The road surface is not consistent nor are braking and acceleration forces applies to the tire, nor suspension loads applied to the tire. I think there are way too many variables in a street tires life to narrow uneven wear to any one thing.

I would be extremely surprised if there was much of a difference in rubber thickness around the tire with the quality tire brands.
 

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If you took a new tire, made sure it was off balance, and ran it until worn out....

At the end of its like, I'd expect wear like this....Question, at that point, would it be closer to or further away from balance? Would running it and uneven wear, make it closer to balance?

You guys woudl be proud..I balanced my own lawnmower blade....balanced it on a screwdriver blade. Guess what? It worked like a champ! LOL
 

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Has anyone else experienced it on a motorcycle where you let go of the bars and as the bike slows down it starts to get head shake, gradually worse and worse until you have to grab the bars? Tends to happen at the same speed over and over....

This happens because the front tire is out of round. Now it did not do this when the tire was new, because when new the tire was round. Tires do not wear evenly.

Now you can balance the front tire/wheel assembly when you have this happen, and you will notice it will keep on happening. The only fix is to replace the front tire.

Tires don't wear evenly because what they touch is not even and the forces applied to them are not even. That is my opinion anyway :)
 

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Absolutely. In my experience it's right around 40-45 mph and multiples thereof. And it sometimes has NOTHING to do with the tires. I've experienced this when:

Put a top case on a '90 VFR. Anything over a pound or two in it and got that symptom.

Ventura luggage on multiple VFRs did this IF the case was mounted behind the rear seat. Flip it around so the bag was over the passenger seat and all was stable.

An ST1100 with what turned out to be a bent rear shock rod (new from factory) had this same problem.

Dunlop tires in the early 90's on my VFR did this after a couple thousand miles. They cupped and vibrated and caused the headshake as well. Running them at lower pressure solved the problem but I didn't like the handling.

A Metzler bias ply tire on my '87 VFR did this from new. Took it back and got it rebalanced. Same issue. Finally someone noticed the runout on the tire was out of spec. A new tire fixed the issue. Runout, in this case, was left-right motion of the tire when you spun it on the balancer. It was about 3mm and the maximum spec for it was about half that I think.

Flattened steering head bearings did the same thing. Replacing them fixed it.

There were articles back in the day about loading motorcycles and how any weight behind the rear axle was bad news. This kind of headshake was pointed to as one of the symptoms of an improperly loaded bike. It also had a lot to do with fork flex, tire sidewall flex, frame stiffness, etc. so things might be a bit different now with upsidedown forks, stiffer frames, bigger tires.

The thing that always fascinated me was that one finger on the bars and you never knew the headshake was there. Given total freedom, it shook like crazy.

Hands off the bars on the Ninja causes nary a wiggle. See:

Asphalt Mode of transport Lane Vehicle Road
 

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Absolutely. In my experience it's right around 40-45 mph and multiples thereof. And it sometimes has NOTHING to do with the tires. I've experienced this when:

Put a top case on a '90 VFR. Anything over a pound or two in it and got that symptom.

Ventura luggage on multiple VFRs did this IF the case was mounted behind the rear seat. Flip it around so the bag was over the passenger seat and all was stable.

An ST1100 with what turned out to be a bent rear shock rod (new from factory) had this same problem.

Dunlop tires in the early 90's on my VFR did this after a couple thousand miles. They cupped and vibrated and caused the headshake as well. Running them at lower pressure solved the problem but I didn't like the handling.

A Metzler bias ply tire on my '87 VFR did this from new. Took it back and got it rebalanced. Same issue. Finally someone noticed the runout on the tire was out of spec. A new tire fixed the issue. Runout, in this case, was left-right motion of the tire when you spun it on the balancer. It was about 3mm and the maximum spec for it was about half that I think.

Flattened steering head bearings did the same thing. Replacing them fixed it.

There were articles back in the day about loading motorcycles and how any weight behind the rear axle was bad news. This kind of headshake was pointed to as one of the symptoms of an improperly loaded bike. It also had a lot to do with fork flex, tire sidewall flex, frame stiffness, etc. so things might be a bit different now with upsidedown forks, stiffer frames, bigger tires.

The thing that always fascinated me was that one finger on the bars and you never knew the headshake was there. Given total freedom, it shook like crazy.

Hands off the bars on the Ninja causes nary a wiggle. See:

View attachment 80291
Boss we will just have to agree to disagree on this one. I have had a very different experience in my motorcycle life. Having worked at a couple of different motorcycle shops and in doing so having the chance to ride a ton of different motorcycles on test rides and what not, it has always been my experience this happens with a worn front tire and is always fixed with a new tire.

Your Metzler tire experience is another example, although new, it was the runout (out of round) that caused the headshake with hands off.

I have personally experienced slack in a rear suspension linkage causing head shake, but not shaking when you take your hands off the bars.

Typical head shake as most people know it happens when you are leaned over and on the throttle. The tire hits a bump and in doing so becomes out of round, the forces acting on the tire fight to get it back round be keep over shooting causing the wobble that is no fun. Certainly many things can make it happen more frequently or make it more violent, but typically starts out with a bump on the throttle.

I know I would get wicked head shake landing fast wheelies with a low psi tire on my R1.
 

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And next pic we need a one handed wheelie :) Can be a sit down to start with if you like, but then working into a stand up one hander :)
 

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Has anyone else experienced it on a motorcycle where you let go of the bars and as the bike slows down it starts to get head shake, gradually worse and worse until you have to grab the bars? Tends to happen at the same speed over and over....

This happens because the front tire is out of round. Now it did not do this when the tire was new, because when new the tire was round. Tires do not wear evenly.

Now you can balance the front tire/wheel assembly when you have this happen, and you will notice it will keep on happening. The only fix is to replace the front tire.

Tires don't wear evenly because what they touch is not even and the forces applied to them are not even. That is my opinion anyway :)
I've had this on most of my bikes at around 40mph. My Ninja does it right now. Haven't been able to pin down the cause though I haven't tried very hard yet.

Reminds me of that joke:

Rider: Hey Doc, it hurts when I go like this.

Doc: Well don't go like that.
 

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I've had this on most of my bikes at around 40mph. My Ninja does it right now. Haven't been able to pin down the cause though I haven't tried very hard yet.

Reminds me of that joke:

Rider: Hey Doc, it hurts when I go like this.

Doc: Well don't go like that.
You should first re-balance it for sure. It will be informative. After that I bet you $130 that a new front tire makes it go away...lol It's pretty common.
 

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And next pic we need a one handed wheelie :) Can be a sit down to start with if you like, but then working into a stand up one hander :)
I'll hand that one off to bakwheeltango! Can't wait to see that video either.

As I've noted my experience is pretty much limited to VFRs but I only report on my experience. I find this a fascinating issue because no matter how much I've read over the years I still don't quite understand it. Especially the rear loading and bent shock rod causes of head shake.

Personally, I feel headshake is an indication of something out of whack so I try to track down what's causing it because I don't want a "hands off" shake at 40 mph to bite me in the a$$ at 120.

And Hey sqid, riding a motorcycle can hurt you so don't do it! :)
 

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I'll hand that one off to bakwheeltango! Can't wait to see that video either.

As I've noted my experience is pretty much limited to VFRs but I only report on my experience. I find this a fascinating issue because no matter how much I've read over the years I still don't quite understand it. Especially the rear loading and bent shock rod causes of head shake.

Personally, I feel headshake is an indication of something out of whack so I try to track down what's causing it because I don't want a "hands off" shake at 40 mph to bite me in the a$$ at 120.

And Hey sqid, riding a motorcycle can hurt you so don't do it! :)
I think this is where you are me are having a difference of opinion.

What causes a hands off wobble at 60-40 mph has nothing to do with what causes an actual head shake while under power. They are two completely different things.
 

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I saw a sentence in one of the British mags. It said to split up the weights, to both sides of the rim, if using over 10g of weight. .35 ounces, then...if using that much, split the dose in half, and go to each side of rim. It must be true, it was in a magazine.

Regarding wobbles...I wish I were smart enough to understand this page. He explains it....But.....click on it and you'll see the issue. Maybe I can hire Manracign to read it for me?
 

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About six months ago on my DL650, I mounted a new Michelin tire Pilot Road 3 - the first time I put on a pure street tire. From day one, it had an annoying wobble on hard deceleration and certain speeds above 85MPH. So mostly I didn't notice it but I knew it was there. I mount and painstakingly statically balance my own tires. At one point I reseated the tire and rebalanced it but it still had the same problem. I then took it to someone with a Snap-on spin balancer and it calculated the same amount of weight with 1/2" of where I had it placed. That too made no difference. I then statically checked the wheel for runnout and it was fine but the tire had a slight lateral deflection of 2-3mm. I had been an ardent Michelin tire fan and didn't want to believe they sold me a defective tire and it was the last thing I checked. When I contacted Michelin they suggested I take it to an authorized dealer. I didn't do that because I bought the tire online and even if a local dealer agreed and offered some kind of credit it would have been towards an inflated tire with installation costs. I called the online dealer where I bought it but because a few months had passed they were less than sympathetic (I would not have been either). I have since sold the bike but I learned a lesson that you have limited recourse when you buy a tire online and not all new tires are perfect - even from major brands.
 
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