ollysidc

Have just read my Subaru Impreza owners manual, September 2002 edition (on the back cover), section 11-41, tyre replacement, there is a "Warning" section that states: "All four tyres must be the same in terms of manufacturer, brand (tread pattern), construction, degree of wear, speed symbol, load index and size. Mixing tyres of different types, sizes or degrees of wear can result in damage to the vehicle's power train. Use of different types or sizes of tyres can also dangerously reduce controllability and braking performance and can lead to an accident" I feel more comfortable I've changed all four now! Cheers

Hi Have a look at this on another site, the 4th entry down has a couple of drawings relating to the internal vanes in the disc (effectively expelling the heat not keeping it in), hope it helps! Cheers Olly http://forums.racingbrake.com/showthread.php?t=74

Hi, The garage that advised me to change the tyres on the rear don't even fit tyres, so there was no work for them there, therefore nothing for them to gain. Don't think anyone has said that the brand difference affects the diff, just the handling of the car maybe. Did a quick calculation a few days ago (just for the hell of it) and for a 4mm difference in wear from front to rear, one set of tyres will travel one extra revolution/km more than the other, so it adds up on long journeys. I'd have liked not to have forked out for another two tyres, but I feel more comfortable now I have and will swap them over regularly from now on - I didn't do this previously and my cars now done 35k, but I'm not taking the chance any more. Google it and have a general read, consensus seems to be that you should keep them with a similar circumference. Hope this helps Cheers Olly

Think its got a lot to do with the vanes inside the disc itself that will force air out of the disc rather than into it, which might be why you've seen them both ways on the outside. You'd be best to contact the manufacturers and ask them which way is correct. Sorry that doesn't help 100%. Cheers Olly

Will do, should have them fitted early next week, due to be delivered tomorrow, £167 for two from Camskill, not bad really. Will give you an honest update next week. Cheers Olly

Thanks very much for all your replies and advice, I'll be ordering the same new tyres for the rear today and get them fitted asap. Cheers Olly

Hi Have just had two new Vredestein Ultrac Sessanta's fitted to the front of my STI, its just been for a service and the guy has recommended that I change the rear tyres (currently 50% worn Potenza's) for the same tyre thats on the front and do it quickly . The reason being that I could fry the centre diff. Couldn't find an answer to this elsewhere on here - apologies if its been asked many times before. I believe the guy at the garage and am gonna take the plunge (another £180 on top of a £450 service , but thats a lot cheaper than a new diff!), just wondered if anyone else had had the same advice or had a diff fry because of this? Cheers Olly