Roadster Front Tire Wear

[mark1400]

I ride the tail of the dragon, the blue ridge pkwy, the cherohala and the like. Some of the twistiest roads in North America. In 30+ years of riding and road racing I've only ever known cupping to be the result of under inflation.

That said I could be totally wrong about the Metzlers this is the only pair I've ever ridden. They seem ok to me so farand I don't expect great mileage due to the weight of the bike and my ridin style, but so far no cupping.

I check my tyre pressure every week & have never ridden with under 38 psi front.....( i try to keep it at 40)...do you think that is under inflated? What tyre pressure are you using?

 

[HansO]

no less than 42 psi for me, on a trip with trailer bump it up to 45 psi to allow for extra load while braking

 

[1olbull]

no less than 42 psi for me, on a trip with trailer bump it up to 45 psi to allow for extra load while braking

Just just thinking out loud here, Hans.
Are you going the wrong way on the front tire pressure?
Tire pressure has an effect on available tire friction. Therefore, if you add more tire pressure up front for extra forward weight shift you may be creating a more slippery front tire?

 

[Ishrub]

Just just thinking out loud here, Hans.
Are you going the wrong way on the front tire pressure?
Tire pressure has an effect on available tire friction. Therefore, if you add more tire pressure up front for extra forward weight shift you may be creating a more slippery front tire?

'tire friction' bring available tire contact area under compression where a lower pressure would allow greater deformation of tire and increase contact area? I suppose heavy load - 2 up + luggage and even a trailer under braking would counter the high pressure too.

 

[Speedy]

Perhaps a little thought about what causes tire cupping and how it is impacted by load, both static and braking, cornering forces, tire profile, and inflation pressures will reduce the argument to simple facts. All motorcycle tires will cup over time. Some just sooner than others.

Tire grip is a function of contact surface area, load (unit loading,) and friction characteristics of the tire materials (more factors too but complicated.) More pressure and the unit loading goes up which may or may not increase traction depending on the particular tire. If for example, you put 100lbs of pressure in a tire, the contact area becomes tiny. Thus it offers almost no traction and has a very high wear rate in the center only. On the other hand, low pressure increases contact area. This may increase traction but at a significant cost. Tread squirm! The tire must deform both axially and radially to contact the road. Therefore, the unit loading is lower than with greater pressure and it is not even across the contact patch with the greatest loading at the center and reduced loading at the perimeter. So, what happens? The area of the contact patch with the greatest unit loading will be stable, while the outer contact area with lower unit loading must slip as it both rolls into contact and again as it rolls out.

Keep in mind that the diameter of a round cross section tire gets smaller as measured further from the center of the tire. Force it to have a flat surface and the tire tread deforms to accommodate the change in profile.

Therefore, heavy breaking, abrasive road materials, fast cornering and low pressures means more cupping. Sedate riding with high tire pressures reduces cupping but increases flattening of the tire center.

Tire construction as in cord lay, ply angles, etc. and tread compounds and pattern affect tire wear. Being we all ride differently and on different roads, it is not surprising that we have different experiences with tires. Find what suites you. For me a rear tire run backwards on the front has been the best compromise of traction, wear and cost.

 

[mark1400]

Ill try going up to 42psi & see if it slows down the rate of cupping.
Cheers.

 

[HansO]

Actually. Even thinking of trying a Michelin pilot road in a 150/70/17 rear tyre on the front, turned around of course, has any body tried that yet?

 

[Claviger]

Perhaps a little thought about what causes tire cupping and how it is impacted by load, both static and braking, cornering forces, tire profile, and inflation pressures will reduce the argument to simple facts. All motorcycle tires will cup over time. Some just sooner than others.

Tire grip is a function of contact surface area, load (unit loading,) and friction characteristics of the tire materials (more factors too but complicated.) More pressure and the unit loading goes up which may or may not increase traction depending on the particular tire. If for example, you put 100lbs of pressure in a tire, the contact area becomes tiny. Thus it offers almost no traction and has a very high wear rate in the center only. On the other hand, low pressure increases contact area. This may increase traction but at a significant cost. Tread squirm! The tire must deform both axially and radially to contact the road. Therefore, the unit loading is lower than with greater pressure and it is not even across the contact patch with the greatest loading at the center and reduced loading at the perimeter. So, what happens? The area of the contact patch with the greatest unit loading will be stable, while the outer contact area with lower unit loading must slip as it both rolls into contact and again as it rolls out.

Keep in mind that the diameter of a round cross section tire gets smaller as measured further from the center of the tire. Force it to have a flat surface and the tire tread deforms to accommodate the change in profile.

Therefore, heavy breaking, abrasive road materials, fast cornering and low pressures means more cupping. Sedate riding with high tire pressures reduces cupping but increases flattening of the tire center.

Tire construction as in cord lay, ply angles, etc. and tread compounds and pattern affect tire wear. Being we all ride differently and on different roads, it is not surprising that we have different experiences with tires. Find what suites you. For me a rear tire run backwards on the front has been the best compromise of traction, wear and cost.

Makes a lot of sense, as I err, do all of "Heavy breaking, abrasive road materials, fast cornering and low pressures means more cupping", those things regularly, and our roads are ridiculously abrasive in Hawaii.

PSA: 140/75R17 67V, AV-71s are on sale at amazon for $102.88 shipped if you have prime, and $97.88 from dennis kirk: Avon Front Cobra AV71 140/75R-17 Blackwall Tire - 90000001421 Harley-Davidson Motorcycle - Dennis Kirk, Inc.

@Speedy Would love to know which rear you run on the front! I was toying with the idea of putting something from the sport touring world turned around with multiple compounds on the front to get the best of wear vs grip.

Something Like this:

 

[Speedy]

Currently using an Avon Azaro 140/80, but they are no longer available. Next up will be an Avon Storm-3D X-M 150/70ZR17, mounted backwards.

 

[1olbull]

Currently using an Avon Azaro 140/80, but they are no longer available. Next up will be an Avon Storm-3D X-M 150/70ZR17, mounted backwards.

Why not a 140 Avon front tire for the front?