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Front tire cupping
Posted: Sun Feb 17, 2019 10:17 am
by easyrider
Noticing a slight bit of cupping on my front tire left side of center.Is this due to more left turns or balancing or other ?Appreciate comments.
Re: Front tire cupping
Posted: Sun Feb 17, 2019 10:34 am
by Mel46
That is usually because of improper tire pressure. Honda has a "recommended tire pressure" plate(sticker) on the bike on the left side under the glove box.
Re: Front tire cupping
Posted: Sun Feb 17, 2019 12:00 pm
by gn2
Could be camber of the road.
Try driving on the left side of the road for a few thousand miles and see if the right side of the tyre matches the left.
Re: Front tire cupping
Posted: Sun Feb 17, 2019 1:50 pm
by easyrider
Pressure checks are good. Thats an interesting thought on the road camber.
Re: Front tire cupping
Posted: Sun Feb 17, 2019 4:36 pm
by Mel46
This is what Google says about cupping on motorcycles and scooters:
When braking is applied to the front tire, the load transfer over-flexes the tire and increases the tendency for cupping and uneven wear. ... Under inflation and overloading of motorcycle tires are significant causes of cupping and uneven wear, particularly in association with hard braking ...
That says a lot.
Re: Front tire cupping
Posted: Sun Feb 17, 2019 4:44 pm
by NADman
If it's non directional-try turning it around.
Re: Front tire cupping
Posted: Sun Feb 17, 2019 5:46 pm
by easyrider
I believe it is rotational.The cupping is only on one side.If braking was the cause wouldnt the whole tire tread be cupping?I cant recall any real aggressive braking .Could it be defective tire??
Re: Front tire cupping
Posted: Sun Feb 17, 2019 6:14 pm
by davenowherejones
Really cheap suspension on the Forza. There is only one small clamp at the top of each fork. My clamps were not very tight.
I think the front suspension is adequate for 30 mph but not for 80 mph top speed of the Forza.
I bet most front wheels are also out of balance. I put Ride-On tire sealer/balancer in mine but I don't think it does much for the balance. Maybe a little.
My front CityGrip looks awful. Not a smooth wear pattern at all.
I also have a tire pressure monitor on my valve stems that reports via bluetooth to my iPhone. The temperature and pressure varies quite a bit during the day. The rear tire gets very hot since it is right next to the muffler.
I wonder if the right side of the Forza is the same weight as the left side. Muffler (heavy) on right side. Clutch and variator on the left is probably lighter. Both brake disks are also on the right with the muffler.
Re: Front tire cupping
Posted: Sun Feb 17, 2019 8:34 pm
by springer1
Dang !!! There's no bottom triple tree on that front end ???
Re: Front tire cupping
Posted: Sun Feb 17, 2019 8:58 pm
by davenowherejones
springer1 wrote:Dang !!! There's no bottom triple tree on that front end ???
None, you are right.
But it goes 80 mph!!!
Re: Front tire cupping
Posted: Sun Feb 17, 2019 10:27 pm
by springer1
davenowherejones wrote:springer1 wrote:Dang !!! There's no bottom triple tree on that front end ???
None, you are right.
But it goes 80 mph!!!
Well who am I to argue with Honda but ..... I guess it’s just another example how old I (and my assumptions about chassis design) are. Considering our litigation- prone society, I doubt they’d sell an unsafe design.
Re: Front tire cupping
Posted: Mon Feb 18, 2019 11:32 am
by easyrider
I guess Ill ride out this tire until it gets too choppy to live with , then I ll replace it with another brand name and see if the condition is repeated.If so I will do a further look at the forks,balancing,.Could be just the design and weight distribution up front.
Re: Front tire cupping
Posted: Mon Feb 18, 2019 4:27 pm
by gn2
springer1 wrote:Dang !!! There's no bottom triple tree on that front end ???
Wrong way round, there isn't a top one.
The Silverwing FJS600 doesn't have one either.
Weighs around 40 kg more than a Forza and can easily maintain 90mph two-up with luggage.

Re: Front tire cupping
Posted: Tue Mar 26, 2019 5:18 pm
by davenowherejones
My front Michelin CityGrip has a fair bit of cupping. I have been running at the recommended tire pressure.
I am going to replace my worn out CityGrips with Mud and Snow Heidenau K66 scooter tires just for a silly expensive experiment.
I am also going to increase the tire pressure in the front to 29 psi which will also be the rear pressure.
ps Does the Forza show 1xx,xxx after 99,999 km or does it go back to zero?