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Exactly my point. It’s ok in Subarus book to put a spare on with 13mm rolling radius difference, but not replacing all four tyres if one pair still has 4mm left and a new tyre has 8mm is going to bolox the gearbox/diff up?
Space saver is only temporary in other words no other option , the wrong size long term is going to cause more issues than a short term use of a space saver , as i said i won’t use mine for exactly that reason , i have some tyre weld that is my temp fix and then maybe repair which they say you may not be able to or replace , modern tyres a lot less prone to flat tyres 👍
On Dons comment ,the man of all knowledge 👍👍 I heard about the tyre size in theory being the same brand to brand but are not 👍
it would be interesting to know what the difference in diameter different tyres have, they should put that info in tyre tests when certain magazines conduct them.
I can understand if staggered sizes were used it would cause a problem, I had new rear tyres on the back of my Volvo once, same brand as the front bit the garage ballsed up and put 225/50 on instead of 205/50 and that made the car have a melt down and confused it into thinking it was wheelspinning everywhere, tc coming on all the time etc.
Exactly my point. It’s ok in Subarus book to put a spare on with 13mm rolling radius difference, but not replacing all four tyres if one pair still has 4mm left and a new tyre has 8mm is going to bolox the gearbox/diff up?
The point being the space saver isn't staying on the car for thousands of miles and it's 13mm DIAMETER difference not radius.
The Gtr is staggered but it’s designed that way , it’s effectively a rwd car , I suppose they don’t put actual sizes on line between different brands as they expect the car that’s it’s fitted to is just one brand on all four wheels so it would not matter , at the end of the day people can do what ever they want , im sticking with the advice I’ve been told 👍😁😂
The point being the space saver isn't staying on the car for thousands of miles and it's 13mm DIAMETER difference not radius.
im not having a go, or trying to be argumentative. Just trying to get my head round it. That is still 6.5mm which is the difference of a bald tyre and a fresh one (if the same brand of course) and that is within Subarus spec?
Mentioning a space saver is probably a little extreme on my part.
There are, however, many Subaru drivers that don’t frequent owners forums and have no idea that it is better to use same brand tyres all round, or to replace all four at once.
I wasn’t aware that it can supposedly cause damage, and I’ve been on here a while.
I have never been advised by a tyre fitter or garage that this should be done either, the suggestion that people that run a Subaru with different brand rubber front to back probably scrimp on maintenance in other areas is possibly a little unfair.
Wrxrowdy , if it’s on line and subaru say don’t do the mixed tyre set up , to me it’s an indication that some one is not looking after their car in the best way , but that’s just how I feel , it does not mean every one else is of the same opinion , it is not a reflection on your service schedule etc , but causes me concern and would put me off buying a car , for the simple reason if they are not doing tyres at 200£ what else are they not doing 👍
The chances of breaking the drivetrain due to tyre mismatch is pretty slim....it's not a Vauxhall Calibra
That said, it's not optimal either. Bear in mind Subarus use different diffs depending on year and spec: Rears had viscous or plated LSD, whilst centres varied between passive plated, viscous which in turn varied from 8kg to 20kg/m rating and also active (DDCD). All are pretty robust. But if you did have a odd tyre, it would be less strain if placed on a axle without a limited slip diff, in other words...the front. In extreme situations a viscous would overheat to the point the silicone fluid (non-replaceable) degrades or the clutches burn out...similar to damage done by doing long burnouts and multiple donuts.
Anyhoo, my experience of mismatching tyres goes right back my early years when I had a new pair of Pirelli P600's on the front of my XR3, which then started wildly torque steering off to the right when hoofing it. After much head scratching and wondering if I had a knackered diff or lower arm bushes or something, I swapped wheels front to rear - problem solved.
Turns out that whilst both tyres were new, same make, model, size and load rating. One was H rated the other was V. That was enough to screw up the handling.
Anyhoo back to PS4. They are quite soft sidewall tyres compared to the PS2 and PS3 (and RE070's !), so personally I'd go XL on the premise it should be a heavier duty tyre. Price difference doesn't mean it's better/worse, it's more to do with supply/demand and if it's a OE fitment tyre
Last edited by ALi-B; 30 October 2022 at 05:18 PM.
Having fitted the two Pilot Sport 5 tyres to the rear, the starting tread on a PS5 appears to be about 8mm, I can say I'm definitely going to get two more for the front.
I moved my old Bridgestone Potenza Sport to the front, approx 5mm tread left. However, whilst the Bridgestones aren't essentially a "bad" tyre, I just don't think they are suitable for newage STi application, not for me anyway. The compound is quite hard in comparison, and doesn't feel as sticky. They have been ok in the wet to be fair.
Whilst the rolling resistance isn't miles apart in terms of tread depth front to rear, there is a significant difference in the compound of the rubber. PS5 is sticky, very sticky.
It's as though the rears far out perform the fronts, it's like a car of two halves in a way. The front is not as planted, the steering feels light and almost scrabbly when pressing on.
I'm getting a better, grippier push from the rear, leaving the rears saying to the fronts..."Is that all you've got?" best way to describe it lol.
Of course though, the power split is more biased to the rear which I'm aware of.
I am getting more road noise from the PS5 at the rear, but I don't mind that, bring it on, I see it as they are gripping better. I'm really hoping now that I've finally found a tyre that has at least a similarly sticky compound to RE070's that I used and loved for years...but cannot get anymore, man those things even just looked good on the car.
I hope that PS5 all round will see the car gripping better at last. We'll see.
28 October 2022, 04:03 PM
