Value to changing all 4 tires to same type?

[sickaroll]

I bought my Puma late last year, and the second thing I got 'fixed' was a big set of winter wellies on her. Now, it didn't snow nor was there any ice this year, but better safe than sorry.

I've got a track training day coming up, and I'm going to put back on the Summer tires.
Tires were a bit mutt when I bought it, 2 front tires were Firestone Firehawk Tz200s, which seem to get ok reviews, and the back has a Continental and something I've never heard of.

I've ordered 2 new Toyo T1Rs on the strength of recommendations here, and tyretest.com results, and I plan to put them on the driven wheels, and throw the Firestones on the back.

How much is it going to affect grip with different tires front and back?
Can't stretch to 4 new ones this month, but if it's really bad I suppose I could get two ones for the rear next month. Thoughts? Is anyone else on a mutt set?

Edit: Just looked up my winter tires, turns out the Semperit SportGrip I have on the rear may not even be real winter tires..
http://www.tyretest.com/wintercar_tyres/semperit/sport_grip/index.html" onclick="window.open(this.href);return false;
Front were more convincing;
http://www.tyretest.com/wintercar_tyres/continental/wintercontact_ts_760/index.html" onclick="window.open(this.href);return false;

 

[plasticsniffer]

The best way to ensure predictable handling is to use the same tyres all round, but I understand your predicament. I would suggest making sure the tyres are all undamaged and at the correct pressure for high speed work. Bear in mind that track work is incredibly hard on tyres, and you may need to up the pressures a little. Check them throughout the day at any opportunity to make sure they are still OK. Don't just look at the outside edge, the inside edge can take even more punishment, depending on the suspension. I might put the old dodgy ones on the front to finish them off, with the good ones on the rear. Understeer is usualy easier to deal with than oversteer! Put the new ones on the front after the track session, as with front wheel drive, the front will get the most punishment on track. It's not beyond possible to destroy a pair of tyres in a day on the track. (I've seen a race slick destroyed after 5 laps of practice!)

 

[sickaroll]

yikes, thanks, I'll bear that in mind; ended up getting just two Toyos, and when I went to put the old Summers back on, one was shredding, so I had to buy a refurb bridgestone mutt in the tyre place, gutted.