Tyre Choice

[Rob Berson]

I need to buy some tyres for my 14x6 rims that I will be fitting to my Alfetta to meet group S specs.
What is the tyre of choice? From what I can see there is not a 205/60/14 available that is CAMS approved.
I would like to use Toyo R888's but they are only available in 185/60/14. I also assume that we are not allowed to downsize to 13" rims for which there are 205/60 tyres available.

Thanks

Rob

[Scott Farquharson]

Hi Rob,

You may struggle with the 205 width on 6" rims.  195's are the best fit and are used by most and are proven.

This is from the tyre thread:

http://www.cams.com.au/bulletins/B06-014%20Historic%20Group%20N%20-%20Approved%20Tyre%20List.pdf

Tyres must be from the production car list which I have just posted in the group s news section and must be 60% profile.  Most Alfa competitors are running the Yoky A032 which has just been superseded by the A048 which has been just added to the production car list.  The AO48 is the control tyre for a number of classes (eg Aus Prodn Car Champ) and is short supply ATM but should free up by the time we are ready.  The size is 195 60 14.  The supplier has said that based on testing the A048 is faster than the AO32.  You can use other tyres if you want as long as they are from the list.  A048's are about $230 each.

Updated Tyre list:

Note the Bridgstone RE 55 and the Dunlop D01 have now been added .  Some reports have the RE55 as being comperable to the Yoky A048.

Bridgestones available from Trackside Tyres (Craig) 03 9761 5557
Dunlops from Stuckeys (Russell or Michael) 03 9386-5331

http://www.camsmanual.com.au/pdf/0810_0701.pdf

As for tyres you should probably stay with either the Bridgestone RE55 (Trackside Tyres - Craig 9761 5557) Yokohama AO48 (Traction Tyres 9764 2811) or Dunlop D01 (Stuckeys 9386-5331) in a 195 14 60.  I have used the Bridgestones and the Yokies and both were excellent.  I have used the D01's on other cars but not in this size and they are pretty good too.  Price will be the factor.  Bridgies and Yokies are about $950 to $1050 a set.

Having said the above it seems CAMS has just released a bulletin on Group N & S Tyre List!!  See below link.

http://www.cams.com.au/bulletins/B07-090%205th%20Category%20-%20Group%20N%20and%20S%20Tyres.pdf

As per the above 195/60/14 in either Bridgstone, Yokies or Dunlops are the go.

Can't use 13's - must use as per spec sheet. 

But really the 195/60/14's are fine - good enough for a 1:56 at the Island and a 1:40 at Winton Long - so they do do have some grip.

[Rob Berson]

Scott

Thanks for the great advice as always.
There seems to be an even newer (2008) CAMS tyre update which includes Toyo's again, but they only stock 185's.
Will check price and availability on the 3 that you recommend and decide from there.

Rob

[alfagtv58]

I have used both the Yokies (A048) and Bridgestones (RE55) in 195/60/14.  Both seem to be very good, and although it is yet to be proven but I have heard that the Bridgestones do keep grip throughout the life of the tyre wheras the Yokie tends to "go off" as the tyre wears......come to think of it, I think I may have heard this from a Bridgestone employee!!

[Scott Farquharson]

Updated Tyre List for 2008

http://www.camsmanual.com.au/pdf/historics/0810_Approved_Tyre_List_Q108.pdf

[adriank]

Gents, wondering if you could advise me re my setup for my GT 1.6 Jn.

Standard wheeels on the car now are 14' x 4.5' or 5'? Pretty sure i'm running 185/70/14 but cant check at the moment.

If someone could advise what is the standard setup, so i can then calc the rolling dia. difference based on a new setup with a new set of rims to run the Yoky A032's 195/60/14.

What is the best width rim to use with the A032, 14' x 6' or 14 x 7'?

thanks, Adrian

[Paul Gulliver]

The following link maybe helpful in this process

http://www.miata.net/garage/tirecalc.html

I don't know what you intend using your car for but I would probably stick with the 185 X 60 tyres.
I have gone from 195 X 60 back to 175 X 60 on my 105 GTV. It has certainly made the steering a lot lighter and sweeter for everything but track work.

Also just remember that these cars came out with 165X60 tyres originally.   

[Scott Farquharson]

Hi Adrian,

Is this for Group S/N?

If so you should check to see if CAMS have a Specification sheet for the 1600 Jr - we don't have one posted (if you get one could you scan and post?).  The 1750 spec allows up to 6 x 15 wheels and up to 195/60 tyres.  I would imagine the 1600 is the same.  If so, the 195 60 14 would be the choice (same as we are all running)

VRA allow a maximum of 15 x 7 although if the logbooked category says less I would think the lower applies - could someone from the VRA confirm - Bill?

If Grp S/N then go wiith the 14 x 6 with 195 60 14 - this works well.  Tyres available are as per the thread above. Not sure of this size in the Toyo's?

I wouldn't worry about the standard setup, just get the OD of the tyre (from the manufacturer) and then you can claulate the rest with gear ratios and final drive.

[Scott Farquharson]

Hey Paul,  Handy calulator!

[Fast Eddie]

If Grp S/N then go wiith the 14 x 6 with 195 60 14 - this works well.  Tyres available are as per the thread above. Not sure of this size in the Toyo's?

Toyo skip the 195/60 and offer a 185/60 or a 205/60 for a 14" rim

[adriank]

Scott, thanks for the info.

For the moment the car will just be a regular driver with some new alloys, i like the look of the Yokies, which come in 195/60/R14. This would mean i should go the 6' wide rims based on your recommendation.

Would there be any potential issues if i went with a 14x7' size?

[alfagtv58]

Here is another calculator I pilfered from somewhere on the net....cannot remember where though, so if it is yours, apologies and let yourself be know to me and I will credit you!!!!!!!!!

[Scott Farquharson]

Here is another calculator I pilfered from somewhere on the net....cannot remember where though, so if it is yours, apologies and let yourself be know to me and I will credit you!!!!!!!!!

It only goes to 6000 rpm....i wonder if any excel genius's could modify it to go to 7500rpm?

[Scott Farquharson]

Scott, thanks for the info.

For the moment the car will just be a regular driver with some new alloys, i like the look of the Yokies, which come in 195/60/R14. This would mean i should go the 6' wide rims based on your recommendation.

Would there be any potential issues if i went with a 14x7' size?

Nothing other than finding a good wheel with the right pcd and offset.  Look if it's for road use and not Grp S - the sky is the limit - I am not much on current road tyre/wheel combos but you could go up to a 205/55/15 on a 15x7 wheel.  I personally like the look of the 14x6 minlites with the 19/60/14's but that's just me.    It is only for Grp S/N where the 14x6 and 60 profile tyre is essential.  Certainly if you intend to sprint or later race the car getting the right wheels now is a bit of a help.

[Alan Hopla]

Calculator modified to run to 7500 rpm.
Also adjusted 4th & 5th gear graph scales to go beyond 240kph
Exposed gear ratio setting area
Adjusted calculation formula, replaced the value of Pi which was 3.04 with 3.14

Haven't tested overly for robustness, but hope it helps.