Bad news? Running different treaded tires front and back?

[Ferrariguyma]

I have been trying to find tires to fit a new set of rims I'm buying from Dave at TRE. I found a set of 205/50ZR15 Dunlop SP Sport 9000 Blackwall for the front 15x7's and 245/50ZR15 Dunlop SP Sport 8000 Blackwall to fit the 15x8.5's in the rear.

My question will there be any ill effects in handling running different treads front and rear?

Thanks sorry if this is a Duh question.

Andrew

[87coupe]

From what I've heard different tread patterns front & rear can cause "tram-lining" and all around squirrelly driving characteristics. I don't have personal experience running mixed tread patterns, so take this as second hand info

Cheers,

[Ferrariguyma]

I looked at the treads photos on tire rack and they look very similar on the 8000 and 9000's they are just not exactly the same, real close though.

[johnsjmc]

Diff tires front and back are not usually advisable.That said you are at least using tires from the same mfg.The Dunlop 9000 may be the "official" replacement for the 8000.Is the carcass construction similar also?

[Ferrariguyma]

Does anyone know if the "carcass's" are similar?

The stock on the 245's (8000's) is listed as very low at Tire Rack and I do not want to order them without knowing if it is a really bad move to run Dunlop SP 8000's in the rear and SP 9000's up front. Anyone???

Thanks

[RarlyL8]

It depends on what you plan to use the tires for.
If it's a street-only application your'e probably OK. Drag racing guys do it all the time.

[ThePointman]

Depends on your car and the condition of the suspension components. To say it will cause no effect is down right ignorant and plain wrong. On some cars it may cause no effect because they have solid suspension with newer tires plus minimal suspension wear or high perf parts etc ... yet that is weak at best. On many cars different tread patterns can spell disaster! At higher speeds you could experience steering bumps that could cause you to crash into another car or end up off the road.

My personal experience with my 85 Carrera Coupe is this,

It has worn suspension with Yoko's that are different models. Even having different models that are the same brand front to back can cause consistency front to back to come into question.

You are taking your life into your hands so be carefully when mixing tires. If you don't believe me go to a tire shop and talk to someone.

[Ferrariguyma]

The wheels and tires in question would be for a street only application and I rarely drive over 80 on the highways in New England.

So I am still questioning whether going with the mixed treads is a ok or a horrible idea.

Thanks for all of the input so far.

[CharlesJones]

I run Dunlop SP9000 on the rear and a pair of Michelins on the front. I only drive on the street, but I've racked up probably 10K miles with this combo, have driven 140mph plus and regularly drive over 110mph. I haven't experienced any problems or unpredictable squirrelly handling with this set-up.

I find it hard to believe that running different tread patterns fore and aft is an issue for the road. Surely there are so many other factors determining the physics of the traction front and back, including the different tyre widths for a start, that I can't see what difference tread pattern makes.

I wouldn't mix tread patterns on the same axil though. And I have to confess that I'm far from knowledgable about this subject - this is just my opinion.

[Ferrariguyma]

From someone who is actually running different treads front and back.

Im going to go for it and see what happens.

Thanks again.

[wholberg]

When I bought my car, it had 8000,s(205's) on the front and 9000's (245's) on the rear. On my car, the front end tended to push (understeer) under hard powered turns. I found that I had to lift up to slide the rear around and get the car pointed before I got back on the power. Of course, in normal day-to-day driving I never had any issues. When those tires wore out (it took a year), I put a set of Yokohama AVS ES100's, and these tires reduced the understeer to a great extent.

The problem with two different tread patterns is at the limits of adhesion. Normally not a problem on the street unless you need to react evasively. If you don't autocross, find an empty mall parking lot on a Sunday morning and see what the tires will do with extreme manuverings. figure out how they behave under panic braking and hard cornering and you should be just fine.

[ja78911sc]

I agree with Wholberg. I had an extra set of Dunlop's which did not match my rears - completely different tread pattern. I used the tires during a DE and noticed significant understeer issues.

On the street the tires worked well under normal driving conditions.