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Old 11-07-2007, 07:10 PM   #1
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Someone please explain this to me.

I just put two new tires on the rear of the car. They are Pzero Asemetico 275/35/18. On the front I have PS2 pilot sport.

I did not put PS2 on the rear because they were on back order, and the front tires are faily new, I will soon replace them with Pzeros as well but for now I left them.

I found that the Pzero tires are very slipperly. From a dead start the tires will spin and smoke, and on turns I feal like I am on Toyko Drift.

I have heard that mixing tires front and back affect the grip, but my question is....

Why would the front tires have any effect on the grip of the rears?

Has anyone else been dissatisfied with these tires?
Thanks,
James

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Last edited by jhandy; 11-07-2007 at 07:22 PM.
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Old 11-07-2007, 08:24 PM   #2
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For them to be slippery from a dead stop I would assume there is a tire issue.

From my experiences i had the ps cuos on my car and took them off for toyos and the car felt like it was on ice all the time. I went back to ps cups a few months ago and feel planted again, my point is the ps cups may be so good the others feel bad.

Please someone who actully knows the answer chime in I am interested in the answer also.
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Old 11-07-2007, 08:28 PM   #3
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Isn't there a break-in period for new tires?
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Old 11-07-2007, 09:07 PM   #4
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This just my theory:
Since the front and back have different threads, and possibly different rubber stickiness. If the front set or rear set is catching and turning before the other set then that may be causing the slipping and sliding your describing.
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Old 11-07-2007, 10:01 PM   #5
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I don't think the front is affecting the rear traction. I agree with the comment, that it might be taking a while to scrub in your new tires.

I used to race motorcycles and spent a good chunk of a season running Dunlops on the front and Michelins on the back. I'd have no problem mixing brands as long as they are both about as sticky.
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Old 11-08-2007, 06:15 AM   #6
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Tires should scrub-in in less than 500 miles. Probably as little as 200. The owners manual says about 200 miles IIRC.

Could be as simples as tire pressures. Maybe they even mounted them on the wrong side of the car.

How cold is it where you are now. Our tires don't have much grip below 40-45 degrees either.
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Old 11-08-2007, 06:37 AM   #7
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You need to take it easy on new tires... they need to scrub in before they work well. The surface of new tires has release agents from production that have to wear off. Dont spin the tires when they are new as you will bond the release agents into the tire and extend the time it takes to scrub them off!

You really feel the difference since the front tires are sticking well, while the rears are slippery and not scrubbed int.
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Old 11-08-2007, 06:43 AM   #8
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I tell you i Pirelli Pzero's up front and SO2's on the rear on the S 17's and they were okay and never really lost grip ,occational slip etc...

I blast my car everywhere i love a bit of tail out as much as the next guy!!!!

I know this is of topic but, I have Cooper Zeon's on my 19's which are the same width front and rear as the 17's and myCar doesnt budge it is locked to the road in the dry and wet, the tyres are just unbelievable. I had never heard of Cooper before now i wouldnt think of getting any other tyre.

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Old 11-08-2007, 06:47 AM   #9
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Temp here in texas is not cold, maybe 60 or so. 50 at night.

I sure hope that these tires have a break in period. They are like ice. On black top road it is nothing to spin the car with the slightest acceleration. On concrete they stick like glue, but i suppose anything would stick to concrete.

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Old 11-08-2007, 07:22 AM   #10
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Jhandy,

It looks like your tires are very different and may not be a good match.

Michelin PS2- wear rating 220, very sticky amazing summer street tire, lousey in cold weather.

Pirelli Asimmetrico- Several models, wear rating 420 I think?? decent all season tire, fair grip in summer, good grip in winter.

Mixing brands of tires is ok as long as you stay with the same tire performance type. Using tires with very different characteristics is probably causing your handling problems. Go back to your tire tech and explain the problem. Maybe you can find a better match.
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Old 11-08-2007, 08:21 AM   #11
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The ones I bought are the Rosso 275/35ZR18
Load Index 95 = 1521lbs (690kg) per tire
Speed Rating Y = 186mph (300kph) 95Y SL Asimmetrico Treadwear: 220
Traction: AA Temperature: A220 AA A 1521 lbs. 51 psi

They have the same treadwear as the PS2,
I guess they will just have to wear in.
I will put Pzero Rosso up front and see if that makes any change, until then , I guess I will just have to be careful.

James
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Old 11-08-2007, 08:31 AM   #12
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Sorry J,
I was not sure which ones you had. My advice is the same though. Talk to your tire tech and explain the problem. He may be able to help.

I currently have PS2's on the front and standard Pilot Sports on the rear. Handling is pretty neutral now but I will replace the rears soon with PS2's for the most consistent handling I can get in street tires.
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Old 11-08-2007, 08:32 AM   #13
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James, what is the tire pressure? Is the rotation arrow pointing in the right direction?

I bet they are over-inflated. Tire shops typically make this error.
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Old 11-09-2007, 01:08 PM   #14
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Quote:
Originally Posted by jhandy
Why would the front tires have any effect on the grip of the rears?
They don't directly impact the performance of the rears. However, since they are made by 2 different manufacturers the tires will have different consistencies.

If you put race slicks on the front and skinny snow tires on the rear, you would expect the handling to be in-consistant front to rear due to the differences in available grip.

Tire composition (1 ply, 2 ply, 3 ply, nylon belts, steel belts, rayon belts etc) as well as the rubber all impact grip. As does tread pattern.As does temperature. As does, to an extent treadwear rating (itself a tricky, inconsistant rating that generally is accurate for "all season" type tires, but can be manipulated by a manuffacturer - ie some "R" comp tires have been "mis labeled" in this catagory.)

So.. By not getting a matched brand/style on the car, you are experiencing some performance differences. It took me a bit to notice the performance differences between the BFG KDWs the previous owner put on the rears vs the Khumo Ecstas he had on the front.

I would allow a couple hundred miles of "scrub in" to see if it gets better.. but it may not.

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