Heads up - tyre problems
 

I thought I would share with the community my experiences of a recent change of tyres that led to issues with my car, a MY05 JDM. Since none of the experts I discussed this with had come across this specific problem before, it might help someone else out there who comes across the same issue.

I had fitted a new set of Toyo T1Rs to my new wheels back in November 2006, replacing the original RE070s which by then had done around 19,000 miles. They have been an OK tyre, at least I no longer had the tramlining of the RE070s, but neither did I have the grip. Still, after another 16,000 miles or so, by February this year I decided to replace the front tyres as the inner edges had worn, and the rears still had 5mm of tread left.

After looking around for replacements, I ended up going for the Vredestein Ultrac Sessantas, in the same size, 235/40ZR18. These were fitted, and I went about my minimal mileage use of the car. However, I started to notice an odd sound coming from the transmission, together with a shunting motion. It seemed to happen when feathering the throttle, maintaining a constant speed on a slight downward slope, and at any speed.

I mentioned this when I had the car serviced, but it seems this is an unusual happening, though we started to discuss having the centre diff rebuilt, as, on the rolling road it could be seen to be alternating the drive from the front wheels to the rear, leading to the shunting motion. So, I came back from the service thinking about getting the car booked in for a centre diff rebuild (no expense spared!).

I then started digging for information, and contacted a couple of people who I respect for their knowledge of Subarus. Firstly, I have exchanged a number of emails with John Felstead, and, having logically eliminated potential problems, he gradually got me to think about the tyres, and went off to see if he could find the rolling circumference of both the T1Rs and the Vredesteins. Around this time I spoke to Dave Hollamby at Gatwick Subaru. He hadn’t come across this particular problem before, but suggested that I try a different set of wheels and tyres to see if the problem persisted. So, as I had ignored my wife, and still had my original wheels and tyres stacked up in the garage, I went back to my semi slicks.

All the symptoms have disappeared with the old setup, and my gear-changing ability is back – another by-product of the shunting issue was that the car snatched slightly with every gear-change – I assumed I was just losing it :)

I took a couple of measurements with the wheels off. The new tyres have 7mm of tread (the Toyos have 5mm) so not much difference there. However, the circumference of the Vredesteins is around 3.5mm greater, so the centre diff was having to compensate, leading to the shunting.

Needless to say, another 2 new Vredesteins are on order, and unless they are just totally unsuited to the car (which I don’t believe) it should be problem solved.

Many thanks in particular to John Felstead and Dave Hollamby, I guess we can add this experience to the pool of Subaru-related knowledge out there – don’t mix old and new tyres, even on different axles.

Have always been told that you should replace all four together when changing them.... Suppose this must be why??

Interesting read.
I get a little Shunt on the orig RE07. There is a little difference in wear between front/back but not a great deal.
Certainly noticed the shunt and whine on over-run when the oil is warm compard to my old classic. It's not loud just noticable.

I must admit, I did ask a couple of people if it would be OK to put new tyres only on the front (and the rears showed so little wear) and no-one seemed to have an issue with it, though I suppose I have always replaced all 4 in the past.

Won't make that mistake again :)

Top post, thanks for that :ok:

Shall i be concerned then, as i have some new toyo tr1 ready to go on the fronts but i cant really stretch to getting rears plus the fact there not really worn.

Thanks in advance

As I said above, the T1Rs on the rears still had good tread - 5mm, so I was really surprised that I had these problems.

New tyres arrived this afternoon, they're already mounted so I'll be putting them back on the car and making sure all is OK.

2 off 234/40ZR18 Toyo T1Rs for sale if anyone is interested :)

16,000 miles out of a set of T1Rs

That has got to be some kind of record.:lol:


This would not have happened if you rotate the tyres fequently,

I change mine round at every service.:doubleup:

IIRC there was/is a Technical Service Bulletin with regards to a 'whine' and it was suggested that dealers check the circumferences of each tyre as one possible solution.

again IIRC the circumference difference Subaru suggest should not exceed 1/4' , which is not a lot:nono: so a small ammount can make the difference:nod:

The same size tyres from various brands can have a different circumference, which is why they suggest changing all 4 at the same time:ok:

Have to say though, I have changed axle pairs in the past without issue. Perhaps its the newage vehicles that are a little more suseptable to the problem?

Hi Iain, when I suggested that they rotate my wheels at a service at Powerstation when I first got the car they said I shouldn't do it, so I haven't.

Don't forget, after 16,000 miles the rears still had 5mm tread left - they should have gone on for ages :)

Youll be telling us you get 40 mpg next..:lol::five:

Very interesting read :five:

Same as that, good post:doubleup:

My fronts wear quicker than the rears so i think i will change them front to back, also front outer edges wear but I think a full geo is needed.

pm me a price, might be interested

that was a good read :doubleup:
a couple of weeks ago i hit apot hole and damaged a wheel and tyre.lucky i have a spare.the tyres was avon zz3,so i put on vredesteins on the rear and have found out the avons zz3 on the front have a softer side wall than the vredsteins even though they are both xload and gives different fill to the car than having all the same make tyres all round.

from wot i have read about vredesteins they are **** hot in wet and dry