Mismatched tyres - something to think about

[Kenneth]

I have seen a couple of poeple at NZ meets with mismatched tyres.

Maybe I should have brough this up earlier...

mismatched tyres can be bad.

The worst possible combination you can have is:

Front: Uni-directional with good grip
Back: Bi-directional with poor grip

With this combination, I have managed to spin out (this was my galant btw) going UPHILL (and a steep hill at that) at a very low speed. It spun so quick it stalled the car (an auto)

Any combination of uni-directional front and bi-directional back tyres is very bad, especially when you get moisture on them (ie: wet road)

If you want to slide about, sure this combo will let you drift the tail end but be warned sooner or later its going to catch you out.


Tyres are also made differently. This means that even if you have tyres of the same size but different specs, they will have slightly different handling characteristics. This can affect your car from very mildly (almost un-noticeable) to having it handle like crap.


If you are going to push your car hard (ie: track, windy roads) and don't feel 100% comfortable with your mismatched tyre setup (because you dont like feeling unsafe) the best thing you can do is put your best tyres on the back.
If you start loosing grip in the front, you back off the throttle and the car is more likely to come back on line or just push a bit wide.
Once the back starts comming around, things get hairy because you have to counter steer (probably) and make sure you dont pull right off the throttle else you could end up with a "tank slapper" (fish-tail or whatever)


This is my experiance with tyres. Unfortunatly I learned most of this the hard way. I was told that my mismatched tyres would induce a very loose back end, but didn't take much heed


In the end, the choice is yours. The worst thing that could happen is you have a serious crash that could have been avoided by better knowledge of tyres... And I know I would regret if I hadn't mentioned it.

[KiwiTT]

I agree Ken. My preference is to rotate my tyres at every service, so I get a reasonably even wear, and then replace all four at once.

[Nick Mann]

I think all of the above is fair comment on any car, but it is far more important on a car with 4WD.

[I-S]

If you don't regularly rotate tyres, always fit new ones to the back, even (especially) on FWD. That will bias the handling to understeer rather than exacerbating snap oversteer.