I think I already know everyone's answer, but want to hear it to be sure before I consider spending money to fix the problem .

Long story short: on the back of my 350Z I've now got a Continental ProContact 100H and ExtremeContact 91Y both 245/45R18 with similar treadwear. I only do standard driving -- no racing. Is mixing the tires in this way very dangerous? I didn't think this could be a big deal at the time when I had the used ProContact put on to replace a slowly leaking ExtremeContact, but an internet search is making me wonder. From what I've read, in general this seems to be a bad idea, but I guess I'm hoping because they're both same manufacturer it's less bad and that when people call it bad they're speaking more in terms of optimal performance than safety?

Follow up: If I manage to find a used ExtremeContact 91Y of the same size and replace the ProContact with it would that be reasonable? What about a new ExtremeContact if the other ExtremeContact tires are only about 1/3 through their life?

Thoughts?

Thanks!

 

Different tires, even the same make on the same axle is not advisable, more so if you like to drive with 'spirit'. You're in CA so you're you're not going to driving in heavy rain conditions regularly, but this then begs the question of these different spec tires and their ability to shift water, which could quite easily put you in the position of having your rear wheel trying to overtake your front (oversteer) and your ability perhaps at freeway speed being able to control this. Don't cheap out looking for a part worn, you won't know how old it is whether its spent its life in the sun etc. Buy a new pair for that axle. Its always advisable to buy tires as a pair for the reason i mentioned earlier, heavy rain, one new tire, one part worn, one shifts more water than the other, even as you say with your standard driving could leave you causing not only you but others in a wreck. Whenever I've go to look at buying a car and see a mix of Goodyear, Pirelli, Continental and Bridgestone on the same car, I walk away, the owner is a cheapass and if he's cheaping out on matching tires, just what else is he cheaping out on.

 

Mixing different tires on the same axle is dangerous. It might work (depending upon the brand and type of tire), but if it does not work, the consequence might be severe.

I’ve mixed tires front-to-rear, but only did it once on the same axle. I say once because the result was horrible.

--Spike

 

So what was the result? I'm failing to see what the issue could be.

 

Hah, darn, the answer was the most expensive option. Well I suppose at least I don't have to replace all 4. Shame having to throw out both back tires. The roads around me are always under construction and I have terrible luck picking up nails etc near the sidewall.

Thanks for the responses--it's good to know for sure.