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Tyre Regulations On The Strip

abcent

By abcent,
in Motorsport Discussion & Builds

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abcent Mentor

abcent

Posted
Posted

Theres an drag event coming up for SAUvic soon and I was wondering.....if i get some wide 15 inch drag slicks for the rear of my 33-t can i leave the street steel radial 17's on the front?

I heard ages ago that if you have slicks, they have to be on all 4 corners...any truth to this?

Can I bang the slicks on the back only and enjoy having traction for once?

Or am I destine to take on the 1/4 on my regular street tyres?

cheers

I've emailed heathcote park, but still no reply as yet... :(

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https://www.sau.com.au/forums/topic/113743-tyre-regulations-on-the-strip/
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MrBlonde Community Regular

MrBlonde

Posted
Posted

Heathcote is not an ANDRA sanctioned track so you are probably ungoverned on tmixing radials and cross plys. But I've never raced at Heathcote .. anyone who has care to comment?

The ANDRA ruling is that you can mix radials on the front and crossply on the rear until you run quicker than 12.50.

But you really don't want to run radials and crossplies. Try it and you'll find out why in the top end.

MS-75 Enthusiast

MS-75

Posted
Posted
Heathcote is not an ANDRA sanctioned track so you are probably ungoverned on tmixing radials and cross plys. But I've never raced at Heathcote .. anyone who has care to comment?

The ANDRA ruling is that you can mix radials on the front and crossply on the rear until you run quicker than 12.50.

But you really don't want to run radials and crossplies. Try it and you'll find out why in the top end.

Last time raced I had my Hoosier X-ply front runners on with the BF Goodrich Drag radials on the rear. It was amusing to watch the ANDR officials comb their regs to find a reason why I couldn't run like that. In short though-they couldn't find one. :) (because there is no rule on that one-and because it's fine as a combo)

As for the radial front/X-ply rear combo-Mr Blond is ,of course, completely correct.

The basic reason is that the radials don't much allow sideways movement of the car on the tyre, whereas X-plys do. What can happen is that the back of the car starts to move around on the tyre-bouncing from side to side, with the front staying put. This can get you into a positive-feedback condition where the bounce from side to side becomes more and more violent, eventually causing the car to sidestep and slide, or roll. Bad bad shit.

Think speedwobbles on a skateboard-but at 100mph plus in a car............. :(

Sean=-)

Al Grand Master

Al

Posted
Posted

Just some further question, from a novice :(

Barely street legal tyres, such as Mickey Thompsons (sp?) and Nitto's, are still rigid enough to run daily standard/road front tyres, as these are still classified as a street legal tyre?

It is only when you go to a full drag tyre that you need to comply with the regs?

MS-75 Enthusiast

MS-75

Posted
Posted

The only thing that governs the combination of front and rear tyres is the construction type.

Drag slicks, front runners and older (very old..) road tyres are of X-ply, or Bias ply construction. (have a siff about on the web for an in depth explanation and diagrams)

All other tyres are of Radial construction.

Nitto drag tyres, MickeyThompson radials(not the slicks), BFGoodrich Drag Radials and Hoosier Radials are all marginal for street use, but are still radials, and as such you do not need special front tyres to go with them (your normal street rubber is fine).

Hope this helps

Sean

abcent Mentor

abcent

Posted
  • Author
Posted

so in a nut shell......I'd be best to look for a set of drag RADIALS for the rear for a little extra grip and to maintain balance of the car.

thanks for all the advise guys, much appretiated!! :)

anyone know where I can find CHEAP 17" drag radials in Victoria?

Z1LLA Proficient

Z1LLA

Posted
Posted
Theres an drag event coming up for SAUvic soon and I was wondering.....if i get some wide 15 inch drag slicks for the rear of my 33-t can i leave the street steel radial 17's on the front?

I heard ages ago that if you have slicks, they have to be on all 4 corners...any truth to this?

Can I bang the slicks on the back only and enjoy having traction for once?

Or am I destine to take on the 1/4 on my regular street tyres?

cheers

I've emailed heathcote park, but still no reply as yet... :(

Hey mate I have raced at Heathcote heaps of times in my cars. You can run drag slicks on the rear and street tyres on the front with no problems up there.

I've been doing this on my Datsun and its recently gone 11.6/119mph with slicks on the rear and street tyres on the front and it has been straight on the track with no problems at all, top end included. Depends how fast your car is going to go I guess.

Heathcote Park owners have been on holidays the past week.

Put the slicks on and enjoy the G-Forces :(

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