One for the Tyre guru's among us....

[MARTINGTI]

So I was at Mondello today with the Celica. Had a set of second hand medium compound dunlop rally tyres on the front. Pressure at 28psi. Ran all morning no problem. Around half 12 got a lot of vibration into the steering and the car pulling badly to the left. Came in thinking brake stuck or something. Checked all the brakes, sliders, pistons all Ok. Iv no idea why but I swapped the front Tyres from right to left and vice versa. Went back out and vibration still there but car now pulling to the right! So now I'm thinking a wheel has buckled or something. So I changed the two front wheels to another set I had with a048s on them. Car was perfect. When I got home I noticed my problem.... Would really love to know if anyone came across it before or what caused it. Now iv ran medium compound before many times, same pressure etc for full days with no issues.... Cheers

 

[Markokavo]

I usually let air out as they heat up.
I drop the 888's to 30psi, but usually up in psi again after few laps.

 

[keith dublin]

I have a set of them on wheels here at home with the same problem I put it down to the rubber been old and having gone through 2 many heat cycles and has just broken down

 

[KENC]

There is a reason tyres like these become available 2nd hand.

 

[midlandbe5]

The tyre in first picture looks to have a bulge in it, would explain vibrations and pull in steering

 

[keith dublin]

Yea it's like the top rubber comes away from the shell of the Tyre and bulges mine are exact same it's pot luck with them really.

 

[toyscrota]

My experience of running the rally car (1600 civic) around Mondello is that you need hard compound tyres.
If they are X12 or X22 Dunlops they will not last. Those tyres must be at least 3-4 years old at this stage.
For them to change patterns etc. they use basic size slick and then wrap another layer around the tyre with the chosen pattern.
As said above they have retracted with heat change too many times id imagine.
If it was a X12 we would set them at 26-27 psi before the start of the stage and they should be up to 32 by end of the stage if they are working correctly, but as i said they wouldn't last around mondello.

If getting rally tyres again try get the following
Dunlop: X04 and X08
Kumho: K51 and K61
Pirelli: RK5 +
Cant buy Dunlop anymore, Kumho off ears.ie (15" are €190 each), Pirelli off Bill Adair (€220 +++)