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10-03-2006, 02:08 PM | #1 |
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So is this what slip angle is?
So is this what tread block deformation during with nonzero slip angle is?
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10-03-2006, 08:57 PM | #2 |
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Don't know the answer to your question... but that looks mighty familiar. Those outside corners of my tires are all torn up (looks like terry cloth)... I'd be interested in knowing as well.
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10-04-2006, 08:27 AM | #3 |
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I don't see any deformation just wear patterns. Seem like it could be camber and toe in, anyone? You're not using those tires enough..
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10-04-2006, 09:21 AM | #4 |
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Yeah, looks like normal wear to me.
Slip angle doesn't have anything to do (directly) with tire wear patterns. http://en.wikipedia.org/wiki/Slip_angle If you're cornering hard with excessive slip angles, then yeah, your tires will wear strangely. Pat |
10-04-2006, 09:27 AM | #5 |
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The scalloped edges look like tread block deformation during cornering.
It also looks like you've got the pressures too high. The wear should come to the top of the arrow. Excessive slip angle usually shows up as lines across the tread, as the tires slide over the asphalt and it acts like 10 grit sandpaper. |
10-04-2006, 01:32 PM | #6 | |
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As for the PSI, I chose this PSI based on pyrometer readings (inside, middle, outside). This is the PSI that gave me more even tire temps. I think the tread block below the scalloped portion is sidewall, although it may not look that way in the picture. I use different PSI for autox obviously. I think the scalloping came from the autox. |
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10-04-2006, 01:36 PM | #7 | |
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Scalloping can develop if you understeer a lot in autox and the side wall doesn't start where you're saying. It's at the base of that triangle is not even further down. My current tires are worned to the letters, to give you an idea. Falkens 615s. |
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10-04-2006, 01:53 PM | #8 |
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If you're on a stock alignment, it's probably because of the nasty camber gain you get during cornering.
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10-04-2006, 02:22 PM | #9 | |
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I'll let out some air from my tires to see. Currently I'm at 37 front, 35 rear (215/45/17). Since, I have added front and rear sway bars to help with the camber loss and will be gettng a negative front camber alignment soon. |
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10-04-2006, 03:26 PM | #10 | |
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Quote:
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10-04-2006, 07:21 PM | #11 | |
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Or maybe I'm interpreting the picture wrong, but that's what my tires look like and I know for sure that I'm getting on the corners of my tires... |
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10-04-2006, 08:28 PM | #12 |
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Ok... I've drawn all over my picture... so heres the legend:
red lines - these are the saw tooth scrub marks that I was guessing is due to my hard cornering during autox; probably during understeering purple line - the approximate border between the patch my resting car sits on and where the tire is no longer contacting the ground (note how the tread block gaps go from the V pattern to the horizontal direction) yellow circle - assuming this is the triangle referred to above as the "arrow" Which would you consider is the "tire sidewall": pink, green, or blue line? I was guessing the blue line was the "sidewall" (because of the purple line) |
10-04-2006, 08:49 PM | #13 |
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I would say the pink is the sidewall. Your aggressive use wear pattern appears pretty good, as the wear is about to the tip of the yellow-circled arrow.
Pat |
10-04-2006, 09:07 PM | #14 |
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My vote is pink for the sidewall.
What does one need to do in order to stay out of the red? I'm running stock alignment maxed out, -0.9 for me. I just got a WL front 22mm adj bar, but that's it as far as suspension mods up front. Is going in the 'red' inevitable w/out camber bolts/plates? |
10-04-2006, 09:21 PM | #15 |
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So, to summarize, my red section is ok *for the tire*, because it's not sidewall.
However, it's better not do have the red area because it means the tire patch is not flat on the ground (positive camber), and thus not as good traction. Is that right? |
10-04-2006, 11:55 PM | #16 | ||
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Quote:
Quote:
Pat |
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10-05-2006, 08:15 AM | #17 | |
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The triangle is the end of the tread patch and if he had pushed hard, the triangle wouldn't be there, mine were gone long ago. This alos means you're using all your treads not just the flat patch of it. On my current tires, the line I have mentioned between the top of the lettering and the botom of the tread blocks are gone. Just a little lower into the top end of the pink line. Hopefulyl that's clearer to you. Like Pat O says, "slow in, fast out" because you want to shave the necessary speed so you can get on the gas earlier. If you're on OEM settings, brake straight will give you better decceleration so you won't understeer as much trying to threshhold brake. |
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10-05-2006, 08:39 AM | #18 | |
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10-05-2006, 08:42 AM | #19 | |
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10-05-2006, 01:15 PM | #20 |
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Oh man, I just realized the tire pictured above was my REAR tire during the autox, and I had since rotated them front/back.
The original tire that was used as the FRONT tire during the autox was this: In this case, I definitely was rolling onto the sidewall. I had 38 psi cold and after my runs, it was 40.5psi. For the fun runs, I pumped it up to 42 psi and that (combined with better driving) produced less understeer and better times. |
10-05-2006, 02:35 PM | #21 |
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are those goodyears F1's
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10-05-2006, 02:37 PM | #22 |
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10-05-2006, 02:47 PM | #23 |
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Slip angle is the angle at which a tire has the most traction. The higher the performance tire, the shallower the slip angle is (with exception to rally).
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10-05-2006, 02:51 PM | #24 |
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I know this is unrelated. I'm getting F1 for my '04 wagon, what are your impressions of these tires? Are those 225's?
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10-05-2006, 03:34 PM | #25 |
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The F1's are stock size 215/45/17 and I love them for what I bought them for: which is everything in California weather.
- commuting - driving my family around (comfortable, not noisy) - great dry/wet grip (no snow around here, except the mountains, but then I switch back to the RE92 on the stock wheels) - autox worthy - reasonable price |
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