Tyre rules ??? For drags...

**ebxr8240** · 05-12-2005, 12:36 AM

I have 17's on my car as std..
I have some slicks that are crossply..
I can't put any smaller tyes on front than 17's due to 350 mm brakes...
Can I purchase radial slicks on the back and be o/k ???
With road radials on front??....

SpoolMan · 05-12-2005, 01:03 AM

Drag radials such as M/T are fine with your everyday tyres on the front...
.
The only time the std front wheels are a problem when you use a full slick the car will weave all over the place if you don't use a front runner with a full slick.

brenx · 05-12-2005, 01:31 AM

It doesn't weave all over the place with a slick on the back and radials on the front. That all depends on tyre pressures and speed. Do it right and their isn't an issue but most have no idea about tyre pressures etc.

I ran MT ET streets (crossply slicks) with radial tyres on the front running 12.950->11.96 for quite a few years. From 03 -> 05.

They are cracking down on it though apparently. I never had an issue but I got front runners after last financial period ended. I plan to go a little faster yet which means the car will get more than just a quick glance.

SpoolMan · 05-12-2005, 01:58 AM

You can not run with a standard street tyre with a full drag slick on the back, they wont allow it, nor should they its very dangerous...
I tried it by getting scrutinized 1st, then making the change on the tyres, my Ute weaved and wobbled at the top end of the track, lent them to Kev, Rodderz and my brother all the same result.

This explains it the long way:
Because front runners are cross ply construction and street tyres are radial. Cross ply don't grip much and radials grip heaps.... that's the whole idea. Don't mix radials with cross ply's construction tyres, simple... If you had radials on the front with slicks back, when the slick sidewall gets out of shape (because of the soft sidewalls that flex) and sends the rear of the car in one direction, your natural reaction is to correct it with a bit oposite lock the other way... With radials that will agressivleyy steer your car the other way sending the *** of the car hard the other way. Hope that makes sense. So guess what happens when you constantly correct the back of your car swinging left and right left and right. It get so out of shape eventually that you end up pointing for the WALL, and prob at high speed!

So with cross ply construction front runners, when you naturally correct it, it doesn't agressivley steer you and the whole car 'drifts' together left to right up the strip...

If you must run drag slicks with radials on the front, either put lots of pressure in the rear to firm up the sidewalls ie (over 15psi), and i find when it gets a 'little' wobbly the best thing you can do if your not going to back off is hold the steering wheel completly straight and floor it as hard as you can and hope it pulls it's self out of it! Its Dangerous.

XRQTOR · 05-12-2005, 10:56 AM

Quote:

Originally Posted by XRFPV8

and i find when it gets a 'little' wobbly the best thing you can do if your not going to back off is hold the steering wheel completly straight and floor it as hard as you can and hope it pulls it's self out of it! Its Dangerous.

Mate of mine got kicked off the track at Wizard for this, it's a big no no.

JG3282 · 05-12-2005, 11:09 AM

Quote:

Originally Posted by brenx

It doesn't weave all over the place with a slick on the back and radials on the front. That all depends on tyre pressures and speed.

Brenx this a very silly comment and is the sort of thing that young up & comers don't need to be hearing/reading

brenx · 05-12-2005, 11:15 AM

My car has tracked dead straight everytime. Only time I've ever had the wobbles is when I swapped to front runners (cross ply). Just my experience and I know many cars are run in the same config. You see them all the time @ Calder and Heathcote. I've seen 10sec pass's done with radials on the front.

xdclevo · 05-12-2005, 08:11 PM

Quote:

Originally Posted by brenx

My car has tracked dead straight everytime.

I know its not supposed to be, but for naturally asperated heavy cars running these sort of times, i too found it fine. I had M/T full slicks and 225 Eager radials on front, and it runs dead strait to 111 mph over the 1/4, and way more than that on a test road we have tested with many times(down to 14 pounds in rear). Still, i too have now got propper front runners and would recomend them if racing, as it is the law and maybe even safer

: .

nugget378 · 05-12-2005, 10:05 PM

I use crossply hoosiers for circuit racing and for the first lap and a half its hang on with all you got till they warm up, I have tried slicks in the XAGT a few years ago with radials on the front and it weaved around a bit but not real bad, just sort of a gentle sway here and there,still I wouldnt do it with my car now

**ebxr8240** · 06-12-2005, 12:52 AM

So I either reqiure Radial slicks or crossply front tyres?
With 400 rwkw I'll deff need to sort this out!!!
New radial slicks ... I guess ???

SpoolMan · 06-12-2005, 01:15 AM

A drag radial will not need a front runner, drag radial has a very firm side wall like your normal street car tyre, they have very sticky tread... the M/T drag radial I have seen George Haddad's 67 Falcon run 10.50 on them @ 131mph..
Give George a call he has the best prices on the M/T Range.
Haddad Race Cars & Engines
16a Amberley Crs Dandenong 3175 (03) 9794 6599
picture here.

brenx · 06-12-2005, 10:32 AM

400rwkw I'd suggest a full slick and front runners but it won't hurt to try the ET street radials. My tuner destroyed a set with only 370rwkw

jcxr · 06-12-2005, 10:46 AM

We know rules are rules, but you could go to your local VW wrecker and get a pair off 15'' conventional tyres and this passes o.k.

toby123 · 06-12-2005, 01:44 PM

GoodYear make front runners for 17" rims.

nugget378 · 06-12-2005, 04:14 PM

Quote:

Originally Posted by brenx

400rwkw I'd suggest a full slick and front runners but it won't hurt to try the ET street radials. My tuner destroyed a set with only 370rwkw

I destroyed a set on sunday,by the time i got the tune spot on they were cactus if only they held on a bit longer,they werent as good as I thought they would be though,I can only fit the 235's due to my wheels offset,I think the 275's would go better

302donk · 06-12-2005, 10:07 PM

[QUOTE=XRFPV8]You can not run with a standard street tyre with a full drag slick on the back, they wont allow it, nor should they its very dangerous...

your dead right there XRFPV8 your on the ball dude out right dangerous!!!!!!
-

**ebxr8240** · 07-12-2005, 04:03 PM

I think up to 130 mph the rules change and e/t times also?? Like roll cages etc....

HEMI POWER · 07-12-2005, 04:37 PM

Quote:

Originally Posted by XRFPV8

A drag radial will not need a front runner, drag radial has a very firm side wall like your normal street car tyre, they have very sticky tread... the M/T drag radial I have seen George Haddad's 67 Falcon run 10.50 on them @ 131mph..
Give George a call he has the best prices on the M/T Range.
Haddad Race Cars & Engines
16a Amberley Crs Dandenong 3175 (03) 9794 6599
picture here.

Mark a mate of mine runs that tyre and has run a 9.2 sec pass @ around the 140 mph.Not a bad effort on a radial tyre.

**Falcon Coupe** · 08-12-2005, 10:03 AM

Quote:

Originally Posted by FPVGT

Mark a mate of mine runs that tyre and has run a 9.2 sec pass @ around the 140 mph.Not a bad effort on a radial tyre.

Was it Balinor ? let me guess, full street trim as well.

08-12-2005, 06:02 PM

Quote:

Originally Posted by Falcon Coupe

Was it Balinor ? let me guess, full street trim as well.

Maybe if I had the horsepower & torque figures you blokes throw around........

brenx · 08-12-2005, 06:07 PM

Quote:

Originally Posted by balinor

Maybe if I had the horsepower & torque figures you blokes throw around........

ROFL

: One of us went and had an engine on an engine dyno. Which shows what's needed. Our XA-XC series vehicles are a little heavier.

nugget378 · 08-12-2005, 06:40 PM

Quote:

Originally Posted by brenx

ROFL

: One of us went and had an engine on an engine dyno. Which shows what's needed. Our XA-XC series vehicles are a little heavier.

Exactly,my mates call mine a block of flats lol

08-12-2005, 07:02 PM

Quote:

Originally Posted by brenx

ROFL

: One of us went and had an engine on an engine dyno. Which shows what's needed. Our XA-XC series vehicles are a little heavier.

Have you weighed your car yet? I thought this weight difference was shown to be crap on the other forum (my XTGT came in at 1540kgs without driver 1630 with,Wato's XRGT came in at 1609kgs without driver 1725 with).

brenx · 08-12-2005, 07:09 PM

Nope, . I have to find a weigh bridge that will do it. Our strips don't have the facilities. I have to find time and a place to do that.

As was stated on the other forum. Another XB was running 10.7's @ AIR (Adelaide International Raceway). He made the effort and came to Vic to run unlike some who whine about our times matching our power. He ran 11.12 or 11.13. A little slower than myself and he has more hp. 617hp vs 588hp. A perfect track comparison. According to the other XB's owners info if I went to AIR I'd run 10.7's as is. That's drive in swap tyres, drop exhaust and race.

I'm just waiting for some more $ and colder weather and I'll race again.

08-12-2005, 07:32 PM

Well brenx,if our tracks are so much better,make the "effort" & race on them.......

nugget378 · 08-12-2005, 07:58 PM

Quote:

Originally Posted by balinor

Maybe if I had the horsepower & torque figures you blokes throw around........

Are you expecting these types of cars to match the moroso,they cant mate.

brenx · 08-12-2005, 08:01 PM

Quote:

Originally Posted by balinor

Well brenx,if our tracks are so much better,make the "effort" & race on them.......

I'd like to see how you go on our tracks. I'd line up.

08-12-2005, 08:18 PM

Quote:

Originally Posted by nugget378

Are you expecting these types of cars to match the moroso,they cant mate.

I never mentioned the moroso mate.

08-12-2005, 08:19 PM

Quote:

Originally Posted by brenx

I'd like to see how you go on our tracks. I'd line up.

Hopefully one day I will get down there or you up here,would be good fun.

nugget378 · 08-12-2005, 08:33 PM

Quote:

Originally Posted by balinor

I never mentioned the moroso mate.

But you claim he dosent have the power he has from his et & mph, what do you base that off if not the moroso, I myself think he is pretty close to the mark coz ive biult a similar engine dynoed it and now raced it