Tire Cupping vs. Tire Wear

[draser]

I see the "tire cupping" being brought up followed by a need to replace the tire(s) but, there's no mention of the review of the bike suspension to understand what is causing the "cupping". Is the term "cupping" used to describe tire wear?

Tire cupping is the actual uneven wear of the tire due to suspension continuous bouncing and not keeping contact to pavement. And that leads to suspension diagnosis and repair, followed by a tire replacement.

Tire wear on the other hand is (more often than not) the squaring up of the center of the tire - this is a uniform wear of the tire. There may be also a side wall wear for those doing a lot of twisties.

What do you guys reckon?

 

[ST1100Y]

load... torque... wear...
The studs deform under above, causing a different angle of contact patch...
Normal to a degree, related to riding style (read: aggressive braking & acceleration vs "coasting" through corners)...
way worse when tire is underinflated (allowing even more flexing)...

This has yet nothing to do with condition or setting of the suspension... (lack of damping leads to a wavy, sinus-shaped wear...)

 

[dduelin]

Often we confuse 4 wheelers and monotrack motorcycles when it comes to wear patterns and causes. Ride a motorcycle in a sporting manner and the tread face of the tire deforms much differently than the 4 or more of a car or light truck. Cupping is a consequence of acceleration and braking forces during varying lean angles. Dual compound tires bring another variable to wear patterns. Michelin for one has experimented widely with percentages of the tread divisions of hard vs soft as well as softness/hardness. They didn’t get it right early in the game. Hard riding on the first few generations of Pilot Roads resulted in lots of wear oddness from feathering to lumpy bumpy wear. The Road series in the 5 and 6 are far better. Bridgestone had its BT21 that wore horribly but the BT023, T30, T31 and 32s got progressively better to great tires.

 

[draser]

This has yet nothing to do with condition or setting of the suspension

Here's some info on causes...

https://motorcyclehorizon.com/what-causes-motorcycle-tire-cupping/ OR....

What causes motorcycle tire cupping?

A rider may be wearing protective gear from head to toe and always practicing defensive driving, but if tires are taken for granted and not regularly maintained, he or she could still be in danger. Once the tires start showing signs of cupping and a rider fails to act on it immediately, safety...

motorcycleaccident.org

 

[Al st1100]

Here's some info on causes...

https://motorcyclehorizon.com/what-causes-motorcycle-tire-cupping/ OR....

What causes motorcycle tire cupping?

A rider may be wearing protective gear from head to toe and always practicing defensive driving, but if tires are taken for granted and not regularly maintained, he or she could still be in danger. Once the tires start showing signs of cupping and a rider fails to act on it immediately, safety...

motorcycleaccident.org

Better not take a corner too fast, hit the front brake too hard in other words ride like your gandma.

 

[dduelin]

Better not take a corner too fast, hit the front brake too hard in other words ride like your gandma.

In both links it did say that some cupping is unavoidable if you ride your motorcycle. Can you imagine that?

 

[ST1100Y]

In both links it did say that some cupping is unavoidable if you ride your motorcycle. Can you imagine that?

Corrected that for you...

Like with brake pads: a tire that doesn't wear ain't doing its job...

 

[Upt' North]

Cupping can be caused by many things but suspension isn't always the answer.
If it was explain the following?
ST11 on BT023's, tyres destroyed after 4500 miles of touring, the front cupped to hell, resembling a worn out MX tyre.
ST11 on T30's, slight cupping after 5000 miles of similar touring use. Tyres worn out
ST11 on T32's, no cupping after 5000 miles of similar touring use. Still a little left on them.
All done on the same bike with no suspension maintenance carried out in between rides. The non ABS bike running uprated front springs and ABS oem shock.
Upt.

 

[draser]

Cupping can be caused by many things but suspension isn't always the answer.

Right, trying to understand what's going on here. Same suspension and riding habits, yet different tire wear. What's your take on it?

 

[dduelin]

Tire construction and rubber compound evolution. I wore out about 30 sets of tires on my ST and favored Bridgestones. BT020 all the way to T31s.

 

[Upt' North]

Right, trying to understand what's going on here. Same suspension and riding habits, yet different tire wear. What's your take on it?

The T series tyres are light years ahead of the BT's.
When I first switched to the 30's the bike was transformed. The 32's were the same leap again, not so the 31's.
Simple progress by the manufacturers in my opinion.
Upt.

 

[ST1100Y]

Right, trying to understand what's going on here. Same suspension and riding habits, yet different tire wear. What's your take on it?

Construction and compound used...
During braking & cornering loads the front tire cross-section "flattens", hence the contact patch changes (actually increases)...
The deceleration torques the stubs/thread abaft, the cornering forces twists also sideways, causing increased pressure and wear on the forward facing/leading/drifting edges...

Same on the rear, cornering loads impress the (normally circular) cross section, trail brake and opening the throttle increase the load hence flexing of carcass and thread surface...
(the reasons the rear is wider then the front...)

So while "performing" the thread pattern isn't parallel to the abrasive road surface, the tires aren't "round" anymore, the contact patch enlarges...

How much deformation and uneven wear is actually happening, is owned to the construction and hard/softness for the rubber compound being used...
The ST's are heavy, high torque motorcycles, hence some tires get just shredded, others (like the trusty Exedra) copes well with those loads...

 

[ASPC]

Some tires cup and some don’t. Same bike and rider. Different tire compounds.

 

[ST1100Y]

There also seems some connection to road surface/layout...
While running across Scotland the T32's on my GF's NT700VA began to show angular wear patterns, front and rear...
Pretty much like this:

Inflation pressures where checked regularly (2.5/2.9Bar)

Riding the very same roads the Exedra on my ST1100Y, wore evenly and round...