Testing the power of the Forum

J Clark · Post by **J Clark** » Sat May 19, 07 10:51 pm

Ok, now that I've hooked you in (and I have because you're reading this

)

I'm currently doing a bit of a rebuild on the Roadie and was wondering what the largest wheel/tyre combo would be that would fit under the rear arches? I was hoping to keep to a stock ride height as I am going for more of a road/race build. However I may still want to take it up the strip occasionally so would be good to stick the biggest possible slicks on for max traction. A pair of monos will be going on soon so could go for increased ride height, but prefer not to. Also what slicks to go for? (Hoosier seem the most ubiquitous)

So as my first thread I am 'Testing the power of the Forum'. One of you guys must have the answer.

Otherwise i'll have to get my tape measure out

Here's hoping

JC

Ian Z · Post by **Ian Z** » Sun May 20, 07 12:10 am

need to double check, but I using 15x8 with think 5-1/2 bspace and 11.5 hoosiers. Probably about 1" spare either side with stock setup. Slick size appears to be only one component of good traction, need to get the balance with everything else.

Dave-R · Post by **Dave-R** » Sun May 20, 07 9:22 am

Getting the tape measure out is the only safe way.

Check your axle is centered too. Usually they are not and that effects your measurements if you are going as big as possible.

J Clark · Post by **J Clark** » Sun May 20, 07 9:48 am

Thanks for reply Ian

I think we met very briefly at York on the 7th, but you had to rush off to the burnout box or something

I have to admit your car looked as if the rear end was a bit higher than standard. The Yellow 69 looked level, but had some pretty big rubber as well.

What's the overall diameter of your tyres?

I've attached some pictures below, I think its your car

and the yellow one for coparison, also my heap. Probably best to wait until new springs are fitted before I take any measurements. It's running pretty low at the moment so guess the old leaves are a bit tired!

By the way are you related to the yellow runner, you both have similar reg plate numbers.

P.S. are you at York the end of the month?

PS/PS Cheers Dave, I'll take that into account also

Anonymous · Post by **Anonymous** » Sun May 20, 07 12:48 pm

I have 10x15's on the back of my 70 Satellite with 265/50R15's on. Not sure of the backspacing though.

Holly · Post by **Holly** » Sun May 20, 07 1:02 pm

Bone stock, 275/60R15s should definately fit at the back, and 235/60R15s up front.

With a centred axle and rolling the enside of the wheelarches you can squeeze 295/60R15s under the back, but it needs to be done carefully ... any more and you have to mini-tub it. On the front if its lowered 235s can rub.

J Clark · Post by **J Clark** » Sun May 20, 07 1:26 pm

Hi Fingers

The overall diameter of your wheels would be around 25.43" seems quite small. Must help to lower the gearing for draging, are they slick, if so what type?

Hi James

The 275/60R15s would be about 28" dia then? The 295/60R15s about 28.9"

I was hoping to squeeze some 10x15" rims in with a tyre dia of about 28" So do you think a tyre around the 275/60R15 size would be the one then?

Thanks guys

JC

Holly · Post by **Holly** » Sun May 20, 07 3:21 pm

A lot of people use that size, unless things are seriously out of whack it's a safe bet ... on the 295s I forgot to adjust the profile to match

If in doubt ask a nearby member if you can borrow their wheels to check!

J Clark · Post by **J Clark** » Sun May 20, 07 5:12 pm

Ok people, now put on your 'clever heads'

What's the deal with drag tyres? I assume the idea is to get the maximum contact area with the track using a nice soft compound. Most people seem to use tyres that have a deep section (high profile). Is this so that the tyre flexes on launch thus creating even greater contact area than normal? I gather relatively low tyre pressures are used, is this also to make the tyre 'flatter' on the track and promote greater 'flex'?

Looking at the pictures I posted above, Ians Red Runner has the classic Hoosier tyres, he said he is running 15x8" rims and 11.5" wide tyres. So his tyres bulge quite a lot as can be seen in the pics. Does this promote further flex?

The Yellow runner however seems to be running a lower profile tyre with much wider rims. So I would imagine that this tyre would 'flex' a lot less relative to the rim?

Well, what do you rekon?

Bring on the opinions

Cheers

JC

Dave-R · Post by **Dave-R** » Sun May 20, 07 6:38 pm

You are correct with most of your comments except for wheel width/tyre width.

It is always best to have a tyre at least the same width as the wheel. Slightly bigger than the wheel width is OK up to 2 or three inches but that is as far as I would go.

The good points for having a wider tyre than the wheel is more area on the ground and the narrow wheel pulls the sidewalls in for more room under the car.

The bad point for it is the side walls do not work as they should and the tyre is not as stable side to side.

For example.
I have a 245/60/15 tyre (9.65") on a 8-inch wide wheel at the front of my Challenger and a 295/50/15 (11.6") on a 10-inch wheel at the rear.

They work out at about the same diameter and at just 1.6" wider than the wheels do not look too wide for them.

Dave-R · Post by **Dave-R** » Sun May 20, 07 6:41 pm

Also Drag Slicks sidewalls tend to bulge out more anyway.

These are 28 x 10 slicks on my car. More narrow than my street tyres but the sidewalls stick out just as much (at rest). They run at 10-12psi.

J Clark · Post by **J Clark** » Sun May 20, 07 9:27 pm

Thanks for all that info Dave

So your drag tyres are 28 x 10" are they fitted to 15 x 10" rims?

P.S. At the risk of hijacking my own thread

(if that's possible, it is mine)

Dave tell me about your GV overdrive, my box is being rebuilt at the moment and with my 4.10 gears it seems just the ticket. Low gears for the track, high gears for getting to the track and maybe also a mix of both on the track

(by the way i'm running an A833 box!!!

just how I like it!)

Cheers

JC

Ian Z · Post by **Ian Z** » Sun May 20, 07 9:41 pm

hi, its Jules, yeah? Running 225/60 coopers for street. The slick/rim combo was bought as is, just money/time thing. The new hoosiers are 27" tall, but the !4x6 (10") hoosiers I did have suited my 3.23 better, but offered smaller 'footprint'. Hence Im getting slightly reduced 60ft times coz of the naff gearing but better grip. I need to launch harder to offset the better grip methinks.
Springs are faily recent new ones which would account for the impression of the 'raise'. I think Colin's springs are old. Hope that helps.

Dave-R · Post by **Dave-R** » Sun May 20, 07 11:04 pm

J Clark wrote:
So your drag tyres are 28 x 10" are they fitted to 15 x 10" rims?

Drag slicks are listed by diameter and width. I just assumed you would figure they were also for 15" wheels.

i have the full horrible but ultimately satisfying story of my GV fitting in full detail on my own message board.

J Clark · Post by **J Clark** » Mon May 21, 07 12:27 am

Cheers Dave...

Ian

People who know me call me 'Jules' , but there is someone here on the board who's username is 'Jules' so best to call me Julian or JC. Anyway thanks for the info great help.
Maybe see you at York 27th-28th May?

Well I think I have all the info I need on this subject for the time being. All that remains now is for me to get those new springs fitted and get the tape measure out. Oh and to refit the gearbox... and an engine might be useful too.....

Thanks

JC