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  #21  
Old 11-26-2019, 08:19 PM
Shizzly Shizzly is offline
 
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Meh, don't let these guys scare you. Put a set of LCAs on the car with a real track alignment and drive it however you want. Colleen daily drives Sparkles and it's a plenty capable track car with a TPC suspension yet refined enough to take to dinner. We run a set of RE-71R (200TW tire) that have seen a few dry and wet sessions this year, but mostly see street miles and long drives to tracks (1000's of miles alone) and have tons of tread left. The scrubs we run last us 6 days or so depending on the track and sessions. Good wear pattern.

I'd also recommend you watch the understeer. Not managing the understeer on the car is a great way to destroy the edges of the tire regardless of setup. Not saying that's what's happening as I wouldn't know, but something to watch nonetheless.
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  #22  
Old 11-27-2019, 07:34 AM
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This guy knows his stuff, listen to him. but speaking of

Quote:
Originally Posted by TomChan View Post
1) Flip the tire(if non-directional).
even if not non-direc, it's still ok to flip as long as youre running in dry weather? ive seen plenty of guys do it - yours truly included - but never heard of an issue (BUT have heard many differing opinions, some mentioning how running "backward" will increase chance of failure given that the loads are now reversed / stressing things in reverse??)
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  #23  
Old 11-27-2019, 08:24 AM
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Quote:
Originally Posted by Shizzly View Post
......I'd also recommend you watch the understeer. Not managing the understeer on the car is a great way to destroy the edges of the tire regardless of setup. Not saying that's what's happening as I wouldn't know, but something to watch nonetheless.
Yup!
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  #24  
Old 11-27-2019, 11:54 AM
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I have another related question. I have read the Michelin PSSs have significantly stiffer sidewalls than the PS4Ss. It has also been suggested the significant edge wear I've experience on the PS4Ss is because the sidewalls aren't stiff enough. Lastly, I got 18 track days out of the PSSs and 13 out of the PS4Ss. Is that why? They aren't terribly different on the track so I can easily go either way.
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  #25  
Old 11-27-2019, 12:09 PM
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The experts will chime in, but my thought is why are you talking sidewalls again? You just got a bunch of great advice, and the only "stiff" mentioned was sway bars and springs.
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  #26  
Old 11-27-2019, 12:16 PM
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Quote:
Originally Posted by John Clay View Post
The experts will chime in, but my thought is why are you talking sidewalls again? You just got a bunch of great advice, and the only "stiff" mentioned was sway bars and springs.
Knowing my dad, because he really doesn’t want to modify his car. It’s intriguing, but perhaps it’s now just which tire if not wanting to modify. And curiosity about maybe the reason one outlasted the other.
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  #27  
Old 11-27-2019, 12:40 PM
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Probably lasted longer because he wasn't driving (understeering) as hard.
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  #28  
Old 11-27-2019, 02:14 PM
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I got the sidewall stiffness idea from another forum. I'm just trying to find out if it makes sense in the context of these two tires.

As for understeer, how would I know? The tires aren't protesting to any extent and I'm getting the same wear on the rear as the front. That could be oversteer, I guess, but I've always interpreted it as neutral.

My driving is much better and smoother than several years ago. I now use trail braking to help rotate the car which ought to reduce wear. I used to just brake straight and plow through, which put a lot more wear on the left front.

My lap times haven't changed much in the last three years. In fact, my best lap at Pitt Race was on PSSs in 2016, but my best lap on any day is normally within a second of that. That's pretty wide for a really good driver but at 10-12 days a year I can't complain. It could be weather. I watch as many videos as I can from people I am confident know what they are doing. I no longer see any differences to speak of between what I do and what they do.

Bottom line is the only thing that has obviously changed for the worse in the last three years is the tires. I'm just trying to find out if that is actually the case and if so why.
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  #29  
Old 11-27-2019, 02:59 PM
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Quote:
Originally Posted by rbpeirce View Post
I now use trail braking to help rotate the car which ought to reduce wear.
This could be the bingo moment. Trailing braking subjects the outside of the tires to a different load than straight line braking. But usually this technique carries more speed up to the corner that'll (or should) make a difference in the lap time. Could be the car is over-slowed to the apex. But I truly wouldn't know. Just armchair guessing.

Only definitive way of knowing is to compare cornering speed, steering angle, and G-force data throughout the life of the tire.

As for the side wall stiffness of the tire my opinion is it makes some difference but not huge because the load from the weight of the car plus dynamic forces far overcomes the difference from one street tire to another. Some race car tires actually have a wall stiffness rating in in-lbs at a specific tire pressure. So tire pressure does change tire wall stiffness, but consequently also changes grip.
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  #30  
Old 11-27-2019, 03:41 PM
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Quote:
Originally Posted by TomChan View Post
Trailing braking subjects the outside of the tires to a different load than straight line braking. But usually this technique carries more speed up to the corner that'll (or should) make a difference in the lap time.
Once again, I hadn't thought of that. I'm carrying more speed into the corner and that is putting more load on the outer edge of the tire. Now that I think of it, the obvious wear has been more recent and correlates with when I figured out how to do this.

Quote:
Originally Posted by TomChan View Post
As for the side wall stiffness of the tire my opinion is it makes some difference but not huge because the load from the weight of the car plus dynamic forces far overcomes the difference from one street tire to another.
Thanks. Good to know.

I had been debating switching back to the PSSs. Looks like there's no real benefit from doing that. OTOH, if I am carrying more speed into the corners, now I have to figure out where I am losing time. I don't have any old data but I have old videos. I'm going to have to figure out how to watch them side-by-side with the newer one.
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