Front Tire Cupping/Scalloping

[2degreesout]

I had a cupping problem on my '07. This is on my '13. 5500 miles on PR4GT's. I run 39psi

Good lawd!! you must really be a really good trail braker.

I wish I could wear out a front tire to that extreme in only 5000 miles. Show us a pic of your feelers on your pegs too.

And on just the one side!! That's some serious right-hand cornering. I've never seen that in all my years of riding, unless you had some seriously under-pressured tires.

I ride a big clockwise loop around the neighborhood...lol Not sure what's causing it to wear unevenly, that is the side (fork) that's fully adjustable. I upgraded to racetech springs and valving 2000 miles ago, could be the cause or maybe I waited too long to do the upgrade?? Not trying to hijack JAB's thread

 

[07FJRVegas]

You're indicating that you have PR4GTs and still have the problem. How many miles on the PR4GT when you started getting cupping?

1500 miles. It's beginning to show. I'm bumping pressure up to 42 PSI, but I doubt it will do any good.

Wow 1500 seems early based on my experience with PR3s and 4s. My current PR4GTs didn't start to show any significant cupping on the front until 8500 miles; they now have almost 10,500 miles and probably have 1000 left in them. Last set of PR3s made over 10,000 miles on the other FJR. Lots of two up/fully loaded riding at high speed on both.

 

[JAB]

You're indicating that you have PR4GTs and still have the problem. How many miles on the PR4GT when you started getting cupping?

1500 miles. It's beginning to show. I'm bumping pressure up to 42 PSI, but I doubt it will do any good.

Wow 1500 seems early based on my experience with PR3s and 4s. My current PR4GTs didn't start to show any significant cupping on the front until 8500 miles; they now have almost 10,500 miles and probably have 1000 left in them. Last set of PR3s made over 10,000 miles on the other FJR. Lots of two up/fully loaded riding at high speed on both.

Based on what I just learned from N4HHE, I'm seeing the beginnings of scalping because they are following the tread pattern. It's slight at this point but it's definitely there.

 

[JAB]

You're indicating that you have PR4GTs and still have the problem. How many miles on the PR4GT when you started getting cupping?

1500 miles. It's beginning to show. I'm bumping pressure up to 42 PSI, but I doubt it will do any good.

Wow 1500 seems early based on my experience with PR3s and 4s. My current PR4GTs didn't start to show any significant cupping on the front until 8500 miles; they now have almost 10,500 miles and probably have 1000 left in them. Last set of PR3s made over 10,000 miles on the other FJR. Lots of two up/fully loaded riding at high speed on both.

Gen2's have a different front suspension than the Gen3 ES. My have some bearing on the difference in performance. Just a guess.

 

[Redfish Hunter]

Gen2s have different front suspension from all Gen3s. The Gen3 "A" model with conventional suspension is very different from the Gen2 even though they look the same at first glance. I am positive that the front suspension on both types of Gen3 is superior to the stock Gen2.

What does not change is the weight, the way that weight is distributed, the power and the available braking force. The FJR seems to almost dictate its own cornering style and that seems to encourage "cupping".

 

[N4HHE]

As mentioned by others, some cupping is very normal.... my front has approx 12000 kms (not miles) and it is showing some minor cupping. Nothing to worry about. So it depends how bad it is.

Cupping is never normal.

Scalloping/feathering is unavoidable on motorcycle street tires.

Cupping is caused by an unavoidable irregularity in the tire multiplied by worn out shock absorbers. It may occur in only one place on the entire tire, and it will cup a section spanning multiple tread blocks.

The rolling circumference of a rounded motorcycle tire constantly changes as one moves out from the center of the tire. This means the rolling "wheel" of your tire's contact patch is larger in the center of the patch and smaller on the sides when the motorcycle is upright. This difference must scrub. The tire will flex from parts of the contact patch trying to go one speed and others another. Tread pattern affects where the patch will scrub, slip, and flex. The blocks of tread move, differently, according to their shape. This results in scalloping/feathering. Same thing happens when the bike is leaned in a turn.

More tire pressure reduces the size of the contact patch and reduces the delta of rolling circumference. Stiffens the tire and reduces "squirm", the motion of tread blocks relative to each other. With more pressure the entire patch may scrub, but at least its more even.

 

[timk]

Or use balancing beads.

 

[RaYzerman19]

In addition to keeping your pressures up, one should get the suspension damping set correctly.

 

[Constant Mesh]

Run slicks with no tread blocks and you'll get fairly uniform wear.

Tread blocks deform when you lean, when you brake, whenever you exert a non-vertical force on the tire.

Obviously adding air makes the tire more rigid with less deformation but at the cost of ride harshness and a reduction of the contact with the road.

Lots of forces are exerted on bike tires. It's amazing that they perform as well as they do.

 

[sath182]

That is not cupping. Cupping is independent of tread pattern, does not repeat with the tread pattern. Scalloping and feathering do follow the tread pattern.

Beg to differ, it's generally interchangeable even when talking about car tires.

Cups or scalloped dips

3 - Cupping (Also Called Scalloping)

Cupping, which is more accurately described as scalloping

I didn't know the difference in terms! Thanks for clearing that up. In my situation the wear follows the tread pattern.

There really isn't a difference. The two terms are used interchangeably.

Based on what I just learned from N4HHE, I'm seeing the beginnings of scalping because they are following the tread pattern. It's slight at this point but it's definitely there.

Like this?

https://biketrackdayshub.com/motorcycle-tyre-wear-guide/

"Are the edges of the tread raised? If you have a raised area on either the leading or back edge of the tread (They mean the line itself here), this is a strong sign that rebound damping on the forks or shock is set either too fast or too slow. Usually if its on the leading edge rebound is too slow, and if its on the back edge its too fast."

Or use balancing beads.

No. Just, no...

What does not change is the weight, the way that weight is distributed, the power and the available braking force. The FJR seems to almost dictate its own cornering style and that seems to encourage "cupping".

Dunlop agrees,

"However, there are steps that can be taken to minimize cupping and uneven wear on a motorcycle: Maintain your motorcycle and particularly your front and suspension. Avoid hard braking whenever possible. Braking causes the tire to grab and wear in one direction. When braking is applied to the front tire, the load transfer over-flexes the tire and increases the tendency for cupping and uneven wear. Maintain your tire pressures. Under inflation and overloading of motorcycle tires are significant causes of cupping and uneven wear, particularly in association with hard braking and/or trailer use."

In addition to keeping your pressures up, one should get the suspension damping set correctly.

+1

Rebound is the most important for tire life. It's why the rear shock only has a rebound adjuster rather than only compression.

 

[eflyguy]

"Are the edges of the tread raised? If you have a raised area on either the leading or back edge of the tread (They mean the line itself here), this is a strong sign that rebound damping on the forks or shock is set either too fast or too slow. Usually if its on the leading edge rebound is too slow, and if its on the back edge its too fast."

I was at a track day with an expert (who worked for Traxxion) and he was helping one of the riders adjust his settings based on those kinds of indicators on the tires, and also explaining the whys and hows..

 

[Redfish Hunter]

Regardless of WHAT the "proper" term is, I don't let it bother me. I know going in that the type of bike I chose and my riding style are going to cause issues with how my tires wear. I buy what I think is best for me, I maintain my equipment as best I know how, and I ride the motorcycle. I have fun with my bike, I enjoy my bike. I could just drive my truck everywhere, but I choose not to do so.

Pop likes to accelerate through a corner harder than I do. This creates a slight "spin" or slip and it shows on the tread blocks. He and I both know this shortens the life of the rear tire but it is his tire, his bike, and his money. I like to brake aggressively. I have always enjoyed the FJR's brakes and I play with this often. It affects the longevity of my front tire. I could care less.

 

[N4HHE]

That is not cupping. Cupping is independent of tread pattern, does not repeat with the tread pattern. Scalloping and feathering do follow the tread pattern.

Beg to differ, it's generally interchangeable even when talking about car tires.Cups or scalloped dips

3 - Cupping (Also Called Scalloping)

Cupping, which is more accurately described as scalloping

Ah yes, the old, "I saw it on the internet so it must be true!"

Civilization is collapsing due to lazy non-thinking by those who refuse to consider the meanings of words they spout. OE is a subset of OEM but OE is what most mean when they say OEM. But OEM is almost as broad and nonspecific as saying "tires". OEM is who makes the component not what the component is or where it was used. OE is exactly the same replacement component as used as Original Equipment.

Cupping is a suspension problem which requires very bad shock absorbers and/or shot ball joints.

Feathering/scalloping is the result of tread block squirm when all points of the contact patch are not traveling at the same speed. This is unavoidable on motorcycles.

I didn't know the difference in terms! Thanks for clearing that up. In my situation the wear follows the tread pattern.

There really isn't a difference. The two terms are used interchangeably.

Very many terms are very wrongly used interchangeably. That doesn't make it right.

 

[Bounce]

Civilization is collapsing due to lazy non-thinking by those who refuse to consider the meanings of words they spout.

Like those who confuse smoked pork products "BBQ"?

Or [gasp] those who use a grill (and worse, gas) to cook and called it BBQing? We all know that BBQ is a noun (not a verb).

 

[mcatrophy]

Civilization is collapsing due to lazy non-thinking by those who refuse to consider the meanings of words they spout.

... We all know that BBQ is a noun (not a verb).

Quote: "There ain't no noun wot can't be verbed."

I do hate verbs created from nouns where there is already a perfectly good verb available. But then, I'm a fussy person where language is concerned. (I can hear all the cries of "surely not?" from my regular readers.)

I suspect both "cupping" and "scalloping" are verbs derived from nouns (a miserable attempt to keep on topic).

Also, some of the arguments discussions above do show the futility of semantic issues, where the same word can mean different things to different people. This is one reason why I'm a fussy b*gg*r where language is concerned.

 

[sath182]

That is not cupping. Cupping is independent of tread pattern, does not repeat with the tread pattern. Scalloping and feathering do follow the tread pattern.

Beg to differ, it's generally interchangeable even when talking about car tires.Cups or scalloped dips

3 - Cupping (Also Called Scalloping)

Cupping, which is more accurately described as scalloping

Ah yes, the old, "I saw it on the internet so it must be true!"

I supported my position with sources that are as reputable as one could reasonably expect for the medium that we are using, I challenge you to do the same with any source regardless of expediency. I'm genuinely interested to see the technical explanation as it pertains to motorcycles. So, gather some sources, and teach me please.

Edit: To be clear, this isn't supposed to be a sarcastic or snide response. only a request to perform reasonable due diligence. I'm open to changing my position given a convincing argument. (i.e. Fred and his ride height adjusters. It takes some thinking to come around to.)

Edited Edit: Re-reading your posts, I think I have misunderstood your position a little bit. So please correct me if I'm wrong. With the aggregate context defining your position as, don't call it "cupping" when it's "scalloping" from tread block squirm under load and the differential rotation characteristic of a curved tire surface. Especially considering motorcycles don't have ball joints, or a scrub radius, and the shocks rarely get that bad because you wouldn't be able to handle it if they did, never mind tire wear. So, the use of the term "cupping" is absolutely separate because it can't apply, thus the misnomer.

And so, this has been a total tangent from the topic.

 

[JAB]

https://www.rattlebars.com/tirewear/index.html

This article explains a lot about what is going on.

 

[sath182]

Heh, that was my third reference link earlier

 

[Bounce]

I like Pi

 

[Redfish Hunter]

I like Pi

What if it R not square?