KymcoForum.com
General => Technical | How To => Topic started by: Stig / Major Tom on December 12, 2019, 02:48:36 PM
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Read an interesting motorcycle article recently about tire wear.
It basically said that some tire cupping is normal, and is not a sign that something is wrong with the suspension, the PSI, the alignment, the rim, etc.
Sure, there can be problems with any of the above - but tread cupping, being normal, is not definitive proof that something is wrong.
Stig
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Most of my front tires cup to some extent as they get worn. Sometimes it happens on my rear tires but usually not as much. The more aggressive the tread pattern, the more cupping there normally is. Braking and cornering forces are the primary reasons for cupping as I understand it. On the rear tire you have acceleration, braking and cornering forces. I think the acceleration and braking forces do opposite things to the tire since those forces are in opposite directions.
The front OEM tire on my Like is pretty much worn out and has some interesting wear on it so I went out and took some pics. This tire has around 5700 miles on it. It lasted much longer than the OEM rear which was worn out in 1700 miles.
(https://photos.smugmug.com/2019-PICS/i-XQJDTXN/0/06825f11/L/PC120001-L.jpg)
As you can see, plenty of tread left in the center but worn out about halfway to the edges. Most of that wear is due to cornering, not braking. There are little strips of rubber hanging off the tire.
(https://photos.smugmug.com/2019-PICS/i-4Wc6wkt/0/be966f8d/L/PC120003-L.jpg)
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(https://photos.smugmug.com/2019-PICS/i-QsSwx72/0/ae3b39c0/L/PC120006-L.jpg)
I had my local dealer order a Pirelli Angel for the front. I just need to go get it mounted. The rear City Grip is also nearly worn out at around 5,000 miles. I'll replace that with a Pirelli as well. I'd prefer City Grips but they don't offer one in the correct size for the front of the Like. The City Grip on the rear has noticeable cupping as well but it's worn out mostly in the center.
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I've read threads on motorcycle forums on this cupping topic for years. I've never heard a definitive explanation. Cupping happens. Move on.
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Cupping with bike tires just seems to happen--- different from tire to tire, bike to bike----bothers you, change tires/try different brand of tire.
Cupping not happening with my 2019 XTown 300i----OEM front tire/rear Michelin City Grip with maybe 6,000 miles.
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What's wrong with my bikes, the front tires on my Burmgan 650s and Kymco MyRoad have the same Bridgestone tires and they all cup the same as the tire wears. There must be something wrong with the bikes, lol.
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At almost 19 000 km on my front tyre the cupping is quite bad. The sharp V- shape of the tyre makes steering even more sensitive than usual on the 12 inch wheels. It reached a stage where I think the contact area between the wheel and road is just too small to ensure a safe ride.
In my case both original wheels were nylon. The center part of the wheel at the rear got worn out and the wheel has been replaced with a City Grip (rubber). The old rear tyre still has about 5% grooves left and at this stage I am tempted to mount it at the front just to see what difference the bigger contact area between wheel and road will cause on a scooter with 12 inch wheels.
The steering on a scooter with 12 inch wheels is simply too direct and sensitive to my liking. If I find any improvement with the old rear tyre in front I will probably go for a new rubber tyre with bigger contact surface at the center.
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What's wrong with my bikes, the front tires on my Burmgan 650s and Kymco MyRoad have the same Bridgestone tires and they all cup the same as the tire wears. There must be something wrong with the bikes, lol.
Please post pic of you sitting the scooter.
"They" say cupping is caused by mostly favoring left cheek riding ( below the equator - right cheek!)
I saw a youtube proofing
Stig
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Please post pic of you sitting the scooter.
(https://live.staticflickr.com/65535/49215970581_460346a6a0_z.jpg)
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Looking carefully in bright light yesterday, my 2019 XTown 300 I, 9,000 miles---OEM front tire is starting to cup---should run to about 15,000 miles at which time, rear Michelin City Grip will be worn out----plan to replace with matched set of Michelin (model I forgot right now) based on past experience with both Burgman 400's and Honda SilverWing 600's----best feature=they wear round!