Tire wear question

[SlowPoke]

Greetings all, first post here. I've been to 3 or 4 Level 4 days of School, ride a heavier Sport Touring bike on the street, Yamaha FJR1300. The guy I ride with has the same bike, we've been to Superbike School together, every time. Our track lap times are very close and on the street we ride extremely similar. At no point does either of us really leave the other one behind. We ride flat roads to get to the mountains but spend most of our riding on mountain and twisty roads.

We were both running the same tires, Pirelli Angel GT's and have been for 50,000 miles for me. Back in August, I replaced mine because the sides of the rear tire were worn out. The front tire was rounded in the wear profile and it looked like a new tire, just with less tread. Nice even wear, no issues, probably had 2,000 miles left on it.

The other guy changed his tires this week because his front was worn out. It had a trapezoid shape on the front tire. I know they are dual compound tires and I've seen them wear like that before. It was pretty severe.

We weigh about the same and our suspensions are setup the same and I'm just curious why our tires wear so different riding the same roads on the same bike. My question, is that riding technique differences or something more along the lines of tire pressure. He's been running about 3-4 lbs less on the front than I do.

We're doing a couple more days of level 4 in the spring so if it's technique related, it would be nice to know so we can work on correcting it (whichever one of us it is) at those level 4 days. I wonder if he's carrying more speed into the corners than I am, or perhaps he's braking harder than I am? It has to be a small detail because we are always so closely matched on the road.

Thanks in advance!

[Hotfoot]

Does your riding buddy trail brake harder and/or deeper into the corners than you do?

When you ride with him, in mid-corner and corner exits, is there a difference between your acceleration and his? Does he pull away from you mid-corner or do you gain on him mid-corner? What about at the corner exit?

[SlowPoke]

1 hour ago, Hotfoot said:

Does your riding buddy trail brake harder and/or deeper into the corners than you do?

When you ride with him, in mid-corner and corner exits, is there a difference between your acceleration and his? Does he pull away from you mid-corner or do you gain on him mid-corner? What about at the corner exit?

That's a good question. He doesn't pull away from me, we are right with each other, but I do know a bad habit I have, especially on the street is engine braking. If I could say one main difference in our riding is I engine brake considerably more than he does. I'm working to change that, so I'm using my brakes more now, but overall, that would be the only difference I am aware of between our riding styles. No one is really putting any distance on the other one, regardless of who's leading the ride at the time.

[Hotfoot]

It seems more likely, to me, to be a difference in riding style than in the difference in tire pressure, although I suppose either is possible. 

It logically makes sense that if he brakes more with the front brake and you 'brake' more with engine braking, that he would have more front tire wear and you would have more wear on the rear, since he is using drag from the front tire to slow the bike and you are using drag from the rear. Either technique is workable, but consider that brake pads are cheaper to replace than engine parts - if you overuse engine braking (like using early, high-rev downshifts to slow the bike) you can create some extra wear and tear on the engine.

I asked about throttle application because tire wear can be a very clear indication of how a rider uses the throttle. Late, hard acceleration creates more wear on the rear tire than an earlier, slower roll-on. A rider that accelerates hard with a lot of lean angle will wear out the edges of the tire quicker.

A personal example - I race a lightweight, relatively low horsepower bike. The tires usually wear pretty evenly, since there isn't huge drive power at the rear. A few years ago, I noticed that some other riders were carrying more speed into corners, braking late and trail braking deep into the corner, for every corner. It isn't my usual riding style but I decided to really give it a try and see what happened to my laptimes. I matched what the other riders were doing, found that my corner entry speeds went up, but my midcorner and exit speeds went down. My laptimes did not improve (although I did get better at making passes into corners, by improving my trailbraking skills and bravery). The most noticeable effect of the riding style was that I wore out my front tire, long before the rear, a clear indication that I was putting a lot more load on the front entering the corners but actually get less drive OUT of the corners.  That was the biggest education point of the whole exercise! 

[SlowPoke]

Thanks for the reply, great information there. Thinking back to our last track session, he said he would catch me as we approached a turn, then I'd start to slowly put distance between us, then on the straight aways, I'd take off, but again, he'd catch me as we approached the corner. I think his words to me were something along the lines of "If you ever learn to use the brakes, you'll be checked out" 🤣

I'm working on it. I haven't quite had the internal switch click that allows me to trust the brakes to that level yet!

Heading to Barber in the spring so I guess that's about as good a place as any to practice my braking?

 

 

[Hotfoot]

Barber is a good place to practice, yes.  

What do you not trust about the brakes? What are you worried might happen? In what circumstances or situations are you tentative with the brakes?

[SlowPoke]

I think it's really just more of a habit that I bring from the road to the track than anything else. Following a coach around helps me more than anything. Once I see, and do, that, then I'm a lot more plugged in. However, I do revert to being easier on the brakes than I should be, I believe. I don't ride like a hooligan on the roads too much, so I just settle into a pattern of being on the side of caution and not needing a handful of brakes at every turn. Then I have to remember at the school days that I need to ramp it up and be comfortable with some hard braking.

I suppose I'm riding closer to my limits on the track and not nearly as close on the street, giving myself that big buffer in skill, should I need it for an emergency. I'm also riding a 650lb bike on the street, vs. the S1000RR's on the track so stopping on them is slightly different

Got any good drills to work on at the track for brake usage?

[Hotfoot]

There are loads of drills available in Level 4. Just tell your coach and consultant on your school day that you want to work on your braking, and they will incorporate that into your day. There is also an off-track bike that can be used to explore threshold braking, learn how much brake pressure it takes to lock up the front wheel, etc. There is certainly no shortage of drills for improving braking technique, and timing, and the visual skills that are needed to support effective braking.

[Cobie Fair]

Hi SlowPoke,

Good thread you guys have going here.  A few comments:

3-4 pounds diff in tire pressure can make a difference.  Bigger heavier street bikes can need more pressure than we run on our bikes, but that can go too high (just reducing traction, via smaller contact patch)

Do you ever do the 2-day camps when you come to the schools?  If so, one thing we should do is get you on the Brake Enhancement Trainer.  That will allow you to get to full braking, and a few things we can do on that bike we just can't do elsewhere.

If you guys come together (and ride your bikes) please bring this up.  I'm sure with a coach looking at both of you, we can find out what the difference is!

Best,

Cobie