Tyre Sizes

[sianb]

Apologies if this has come up before -
I am just about to order new tyres for my 924S.
The tyres I am currently running are 195/55/VR15. I had a look on the kwikfit website and it shows I should be running 195/65/VR15. I didn't trust this so rang the OPC and they confirmed that the aspect ratio in the manual for a 1986 924S is 65 not 55.
I'm assuming that this means I will need to replace all 4 (rather than just the back 2).
Anyone else had any experience of this?
Does it make much difference to continue running 55 or will this affect insurance etc?

Thanks
Sian

[verysideways]

Since your car is not four wheel drive i wouldn't be concerned about replacing just the rear 2 with the correct 65 ratio tyres. As long as you stick to axle pairs you should be just fine.

What you wll notice though is that higher profile tyres will give you a more comfortable ride but give you a little less feedback from the road - on the front this tends to mean that your turn in will be less sharp, on the rear this is likely to mean you'll break traction a little earlier but it should be a bit more progressive.

All IMHO of course (and assuming you stick to the same tyre brand and compound). Hope this helps.

VS

[diver944]

What it does mean is that your speedo is currently over reading by at least 10%

A 195/55 15 tyre has a circumference of 73.6 inches whereas the 65 profile tyre has a 78.5 inch circumference. Your smaller tyres will be making more revolutions for a given distance compared with the standard tyreshence over reading at the speedo. So when you do replace them your car will feel a lot faster as 70mph will be closer to 70 and not somewhere near 60 at the moment

Do you get many speed tickets?

[sianb]

Sorry!

Must have been having a blonde moment yesterday - checked the tyres when I got home and they are in fact 65!
The dilemma I have now, is that I had decided on Toyo Proxes T1-R's but they don't make them in the 65.
Does anyone have an opinion on the Toyo R610? or should I stick with my original plan of Pirelli P6000's?

Cheers
Sian

[domster]

Not many people make 65 profile tyres these days, as the trend is for lower sidewalls (better handling responsiveness from the tyre as the lower sidewalls are also stiffer). As such, you may not get your favourite tyre in the 'odd' size you need.

I think the p6000 is a good tyre and perfectly capable. They are also cheap enough as I am getting a pair for my Merc on Sat I personally wouldn't bother with the Toyos - you could probably do more to improve grip and handling in other areas if you wanted to turn your 924S into more of a weapon... getting geometry/tracking done, maybe changing springs and dampers, all things that may need doing on a classic 924.