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Tire Wear Questions


john120283
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Over the last couple of races, I've noticed that the left front tire on our e46 is wearing a little funny.  The inside 2/3rds of the tire is wearing faster than the outside 1/3.  We are also seeing faster wear on the outside shoulder of the tire.

 

Does anyone have any have any idea of what we can do to correct this?

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Inside wear is to much negative camber and possible to much tow. 

 

Checking the tire temps right after a hard laps would give you the info needed. 

 

Get a pyrometer probe, check inner third tire, middle third and then outter third. Compare the three. You can learn a bunch from the temps like which part of the tire is working the hardest (hottest). All three temps closely the same means you are right on work set up and air pressures. 

 

The more wear on a certain area like your tire would generate more heat. Temping tires works the best with a new set of tires but can still get useful info work older. Trick is to document with a lot book and be consistent in how you check the tires meaning decide your procedure and stick with it. Inside, middle then outside. A probe is more precise but a Lazer heat gun would work in a pinch.

 

Check your tow. A few ways to do it. Tow plates and two tape measures work the easiest and gives reliable info. Start off making sure tie rods are straight. They take a lot of abuse bouncing off the edges of track surfaces and berms. Check to see both are the same length from rack to spindle. Some alignment shops don't take the time to adjust the tow from both sides and keep arms equal. 

 

Your should be able to make your own tow plates or find used ones in eBay. Make sure they not warped. My plates travel with car when ever we race. It's a daily ritual and takes just a few mins.

 

See link

 

http://www.longacreracing.com/technical-articles.aspx?item=47690&article=Setting Toe with Deluxe Toe Plates - Video Tech

Edited by cagedruss
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2 hours ago, Black Magic said:

Check for worn out wheel bearing, ball joints or tie rods. As previously mentioned, bushings as well. 

 

Straight up toe and 3 deg neg camber is not an unusual setup. Your in the ballpark.

The front wheel bearings haven't been replace in a while, so that might be a good place to start.

 

7 minutes ago, Team Infiniti said:

Some tracks wear tires differently then others, any more data you can share?

 

What kind of tire?

 

We've seen a similar wear pattern at Harris Hill and MSR Houston on both Dunlop Z3's, 615k+'s and Maxxis VR-1s.

 

I'm pretty sure that the second from the bottom tire came off of the front left.  These tires (Maxxis 205/55/16) had about 7 hours of track time on them at MSR Houston in July.

 

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IMG_4195.jpg.6e4623627e171b4b2993701d2941f5b5.jpg

 

 

Edited by john120283
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Should probably have at least an 8" wheel for that size tire.

 

We have almost exactly the same wear with a 205/50/15 Z3 on 15x7. I attribute some of that to the wheel not being wide enough to control the tire, your 225 would be worse.

Edited by mender
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The Z3's have been the best ones we've run so far.  We ran the Maxxis on Saturday (see the pics above) at MSR in July and the Z3's on Sunday.  The Z3's held up better and had more grip.

 

The 615k+ seemed to wear quite a bit faster than the Z3's as well.

Edited by john120283
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9 hours ago, john120283 said:

The front wheel bearings haven't been replace in a while, so that might be a good place to start.

 

 

We've seen a similar wear pattern at Harris Hill and MSR Houston on both Dunlop Z3's, 615k+'s and Maxxis VR-1s.

 

I'm pretty sure that the second from the bottom tire came off of the front left.  These tires (Maxxis 205/55/16) had about 7 hours of track time on them at MSR Houston in July.

 

IMG_4194.jpg.444d8630fdd6b18c5d4164507b359283.jpg

IMG_4195.jpg.6e4623627e171b4b2993701d2941f5b5.jpg

 

 

Those look like every one of them have been overheated by too much slip angle. Like they are either way too small or the car is being over driven.

 

More wear on the drivers side front is common at clockwise tracks. However, that is a lot of wear.

 

When was camber checked last?  Do you run the same tire pressures on every tire?  

 

It just looks like you are scrubb8ng that tire across the track.  Do you have understeer that is leading to overseer?  In other words, understeer until the car slows enough to re grip in the front, but since there is a lot of steering dialed in, it leads to the back end getting loose.  Sometimes this is referred to as "hooking".

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34 minutes ago, wvumtnbkr said:

Those look like every one of them have been overheated by too much slip angle. Like they are either way too small or the car is being over driven.

 

More wear on the drivers side front is common at clockwise tracks. However, that is a lot of wear.

 

When was camber checked last?  Do you run the same tire pressures on every tire?  

 

It just looks like you are scrubb8ng that tire across the track.  Do you have understeer that is leading to overseer?  In other words, understeer until the car slows enough to re grip in the front, but since there is a lot of steering dialed in, it leads to the back end getting loose.  Sometimes this is referred to as "hooking".

 

We checked had the alignment done just before the race, and if I remember correctly we ran 35 psi or 36 psi hot in the front and 34 psi in the rear.

 

We actually aren't getting any understeer.  Some of the wear can likely be attributed to the fact that this was a July race in Houston, and the trace surface temperatures were around 120 degrees.

 

 

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59 minutes ago, john120283 said:

 

We checked had the alignment done just before the race, and if I remember correctly we ran 35 psi or 36 psi hot in the front and 34 psi in the rear.

 

We actually aren't getting any understeer.  Some of the wear can likely be attributed to the fact that this was a July race in Houston, and the trace surface temperatures were around 120 degrees.

 

 

I figured it was a hot race.  Blisters are still from overheated tires.  I'm still gonna say that those tires got too hot from either over driving the car or being too small.

 

A tire pyrometer would answer moat of your questions and moat likely save you money and considerable time.

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The Z3s and the VR1s show pretty clear signs of overheating. Tire management is an important aspect of endurance racing, especially on a hot track. Have to back off when the tires start giving up.

 

Our Z3s looked quite good after 6 hours on a mid '80s day but the wear went up noticably the next day in mid '90s temps. After about 3.5 hours, we swapped year-old RE-71Rs onto the dominant side for the last half of the race and they held up very well considering and had more grip than the fresh Z3s. We all could feel the left sides working better than the right sides, and the lap times were almost identical to the day before despite the greasy Z3s so the RE-71Rs were doing more than their share to keep us going.

 

I'm hoping the R-S4s that we're going to will behave like those cycled RE-71Rs. 

Edited by mender
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That is a pretty classic example of "chunking" (where the beaver attacked your tire). 

 

You are outside of the temp\loading limits of that tire. In English that means too much work was being done at that location. Sliding too much, low air pressure (flexes the tire and make different contact patch shape), toe and uncontrolled compliance in suspension (joints) can all lead to this. 

 

Make sure no bushings or bearings are bad in your suspension.

 

Check out our youtube tech series for more instructions.

 

https://champcar.org/mainweb/shop-talk-series/race-tech-with-drew-nabb/

 

Then increase inflation pressure if you need to prevent the chunking. This will hurt your grip, so changing your slippage when driving is a better option for teams with discipline. 

 

Once your tires survive you can work on setup for performance.  

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  • 4 years later...

I took the race tires off to put in warm storage for the winter and found this:

image.jpeg.06236ddb5e57e73380e9d73295a74c8a.jpeg

 

This was from our last race. Track and tires were cold, around 50 F and I was fairly aggressive during the warm-up lap, using braking to get heat in the tires before the green. Slid the tires a few times, then they started to grip. Side to side to slide the rear and get them up to temp (FWD). When the flag dropped I was ready and immediately put in some decent laps. 

 

Looks like I might have been too aggressive on the warm-up braking. The chunks were only off the inside of the front tires, which makes sense given the -2.5 degrees of camber. No chunking on the outer edges or middle, so I'm thinking the old tires (2019) were fine once up to temp but a little fragile when cold. 

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