Front Wheel Bounce

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greggk47
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Joined: Fri Oct 23, 2020 1:02 am
Location: WA, USA

Front Wheel Bounce

Post by greggk47 » Mon Oct 26, 2020 7:55 pm

Gregg (first timer posting):
Riding a 2014 BMW G650GS when all of a sudden front wheel starts to bounce shaking the handlebars while coming home from a 3500 mile trip. Bounce was timed with speed. Kinda like riding a horse at 20 mph and getting more violent as speed progresses. At 60 mph it was so bad I couldn't read the big freeway signs that designate exits. Little background here is front tire has 15,000 miles on it and definitely dished on the tread while the back tire is almost completely smooth. Both tire are tubed and full of RideOn tire sealant. Tires are Shinko 705 running 33 psi in the front which is max allowed and 25 psi on the gravel. Changed front tire and used the old tube. Took a test ride and first 5 miles smooth and then the bounce returns. Checked wheel bearings and triple tree bearings and all are tight. Checked radial run out .080"on the rim and axial run out .034". Checked radial run out on the tire on the rim both cold and after test ride which equaled .100". Changed the tube and test rode the bike with the same results. Totally stumped. Called a friend who suggested changing the back tire which I was going to do anyway. When I laid the tire and wheel flat on the bench to remove the valve stem got about two table spoons of RideOn spaying out. Done this several times before and never got any sealant shooting out. Put new tube and tire on and problem solved. My question to the group is anyone else have this problem? RideOn folks say after 5 yrs product begins to thicken because corrosion inhibitors and moisture begin to evaporate and most people change the tube with the tire. I never have unless tube looks like it needs it.
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tire clockwise.jpg (57.49 KiB) Viewed 357 times
tire clockwise close.jpg
tire clockwise close.jpg (46.74 KiB) Viewed 357 times
distance view.jpg
distance view.jpg (87.66 KiB) Viewed 357 times

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Hugh
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Re: Front Wheel Bounce

Post by Hugh » Mon Oct 26, 2020 8:13 pm

Greetings,

Personally I would never refit a used tube into a new tyre. I don't know about the sealant product deteriorating but it would not surprise me.

No I am not rich, it was simply how I was trained to limit potential failures, not compromise safety and introduce unnecessary complications.

TTFN

Hugh.

Agent Orange
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Re: Front Wheel Bounce

Post by Agent Orange » Mon Oct 26, 2020 8:47 pm

Think the reply from the supplier is your answer,.seeing as you have now sorted the problem. I have used ride on before, used to swap out the tube once the valve stem showed signs of corrosion. ( normally every 2nd tyre..).I never got more than 4.5K out of a front. 15k is unbelievable, surprisingly so. Think you were fortunate not to have a problem earlier if you had the sealant in it for all that time. I suppose there must a limit to the product, and you may of found it.
Welcome :mrgreen:

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SHarper
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Re: Front Wheel Bounce

Post by SHarper » Tue Oct 27, 2020 7:04 am

I had this problem on my F800gs, changed the tube (‘cos I wasn’t sure if it had anti-puncture goo in it) and had the wheel balanced.
Anyhoo, long story short, It turned out that the disks had warped, but they had been on for 57,000 miles.
I ordered new ones, tried the cheapest option, but when they came they weren’t full floating disks I’d been sent, so reordered Brembo ones. Problem solved.

sledgegreen
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Re: Front Wheel Bounce

Post by sledgegreen » Tue Oct 27, 2020 9:21 pm

Do you still have the old tube? Might be interesting to cut it open and see if the ant-puncture goo has solidified.

In order to make the wheel bounce, the goo would have to get so thick that it clumped together. As long as it was able to spread itself around the wheel, it wouldn't affect the balance.

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