Wheel and Tyre track setup

[Nathannnnn]

Just wondering what everyone's preference is for tracking. Do you prefer a square wheel setup (same specs all round) or staggered?

Im getting a set of 235/45 tyres and deciding whether I should run 17x8 +35 all round or go 17X9 +22 Front and 17x8 +35 rear. I already have the wheels to do either.
opinions and advice would be greatly appreciated

I have a dc5r!

[tinkerbell]

i prefer square.

[Lonewolf]

square for me also, allows me to rotate tyres

[Fallenangel]

I'm currently running a square setup exactly like yours 235/45 17x8 +35 (with a 25mm spacer) although in a DC2R.
I personally find having a staggered 255/40 17x9+20 fronts, 225/40 17x8 +35 rear would be a more stable setup.

However it will depend on your car's setup/power/suspension. If you have a stock motor with the usual bolt ons, a square setup will probably work better but it'll be up to your driving style.

[Grant@Honed]

I'm currently running a square setup exactly like yours 235/45 17x8 +35 (with a 25mm spacer) although in a DC2R.
I personally find having a staggered 255/40 17x9+20 fronts, 225/40 17x8 +35 rear would be a more stable setup.

However it will depend on your car's setup/power/suspension. If you have a stock motor with the usual bolt ons, a square setup will probably work better but it'll be up to your driving style.

Do you have any pictures of this set up?

I'm interested in testing a 17x9 front with a 15x7 rear combo on my dc2.

[Fallenangel]

Do you have any pictures of this set up?

I'm interested in testing a 17x9 front with a 15x7 rear combo on my dc2.

I haven't got a photo of the 17x9 / 17x8 setup just of yet as i dont have tyres on them yet. But you'll need a lot of guard work for the front and a fair bit on the rear to get them to fit.
Not sure if its a typo with the 15x7 but it definitely wouldn't be suitable. The overall wheel size difference will make the car unbalanced and extremely tail happy

Also just keep in mind with a 17x9 front, you will not have much turning circle. You'll be limited to less than 1 steering lock but if its only a track setup it wouldn't be a problem, but i'd thought to give you a heads up

[tinkerbell]

pictures?

this is the track-talk forum, not the Appearance forum?

[Grant@Honed]

I haven't got a photo of the 17x9 / 17x8 setup just of yet as i dont have tyres on them yet. But you'll need a lot of guard work for the front and a fair bit on the rear to get them to fit.
Not sure if its a typo with the 15x7 but it definitely wouldn't be suitable. The overall wheel size difference will make the car unbalanced and extremely tail happy



Also just keep in mind with a 17x9 front, you will not have much turning circle. You'll be limited to less than 1 steering lock but if its only a track setup it wouldn't be a problem, but i'd thought to give you a heads up

Why would the wheel size make the car unbalanced? Not doubting you, just interested to know if you have sound reasoning for saying so.

What hits what first? Tyre on guard or rim on tie rod?

Tinkerbell: pictures?

this is the track-talk forum, not the Appearance forum?

Sorry I was unaware track talk had to be purely text based. My imagination is limited :P

[tinkerbell]

Why would the wheel size make the car unbalanced? My imagination is limited :P

wheel size has a direct effect on the "contact patch" of a tyre

imagine (if you can) the "contact patch" of a 9 inch wide tyre fitted to a 17 inch diamter rim and compare it to the contact patch of a 7 inch wide tyre fitted to a 15 inch diameter rim - assuming normal profiles

is one contact patch is larger than the other? which one?

which contact patch would provide the most lateral grip in a cornering situation?

what effect (if any) would this have on the oversteer or understeer tendencey of the vehicle?

[Grant@Honed]

Thanks for your reply tinkerbell,

The contact patch of a tyre is not actually defined by the diameter of the rim (or circumference of the tyre) or the width of the tyre.

Its a complicated concept but the two factors with greatest effect on the contact patch are:

1) The load on the tyre
2) The inflation pressure

Here's a link to the wiki page if you don't believe me
http://en.wikipedia.org/wiki/Contact...act_patch_size

The contact patch of a tyre is also a poor metric to define the lateral grip it can support. Camber thrust also plays a big part.

With our front engine and front wheel drive dc2's we have an approximate 65% front bias weight distribution. This means we have more load on the front tyres than the rear

The reason larger and wider tyres are used in motorsport is that they have a more material to distribute the heat generated at the contact patch through. Basically consistent grip levels for longer than a smaller tyre of the same contact patch. Also the larger tyres make more room for bigger braking systems.

[tinkerbell]

Thanks for your reply tinkerbell,

The contact patch of a tyre is not actually defined by the diameter of the rim (or circumference of the tyre) or the width of the tyre.

Its a complicated concept but the two factors with greatest effect on the contact patch are:

1) The load on the tyre
2) The inflation pressure

Here's a link to the wiki page if you don't believe me
http://en.wikipedia.org/wiki/Contact...act_patch_size

The contact patch of a tyre is also a poor metric to define the lateral grip it can support. Camber thrust also plays a big part.

so are you proposing to run positive camber on your 15 by 7's?

[Grant@Honed]

Camber will still be negative



No need to be facetious

[sleepingperformance]

I am running 16x8 / 15x7 (f/r) on my eg and honestly even tho it feels more direct than a 15x8 on the front, the 16in tyres have a slower compound than the 15in or 17in compounds.

That aside, I would not run a 17in front and 15in rear as the rear will be rolling around too much due to the extra height in the sidewall.

Also if you are looking at running a staggered set up, you do not want to run anything more than a 1.5in variance between front and rear widths.

For a DC5, we would most likely run a 18x10 front and 17 or 18x9 rear. We have found with the square set ups on lower speed tracks that they retain too much mechaical rear grip, causing the car to have a slight understeer tendancy. Good for a novice driver, but for those looking to get every last bit out of their set up, not so good.

On a DC2, to make 17x9's work, you will need to space the lower section of the front quarter panel, along with rolling and pulling of fhe front and rear guards. In turn, this will also require you to run a slightly higher ride height to allow for sufficent suspension travel

[Fallenangel]

Why would the wheel size make the car unbalanced? Not doubting you, just interested to know if you have sound reasoning for saying so.

What hits what first? Tyre on guard or rim on tie rod?

Tinkerbell: pictures?

this is the track-talk forum, not the Appearance forum?

Sorry I was unaware track talk had to be purely text based. My imagination is limited :P

Reasons for being unbalanced (In my opinion anyways) would be It'll change your suspension geometry due to the physical high difference of the tyre+wheel combo. The front will be higher than the rear. Unless you compensate for it with the height of the suspension, then it will screw it up.
Also the difference in overall diameter and circumference between the two tyres really bugs me. I dont like the idea that they are spinning at different rates to each other and the wear on the brakes would be uneven and probably freak the ABS sensor.
However in saying that, i would do a 1 size difference in wheels, such as 18x10 front and 17x8 rear ONLY to fit a bigger tyre (295 possibly) on the front, in which i'll be looking to do in the future.

The tyre will hit on the inner guard since we can't adjust caster (unless you got special camber arms) to bring it forward.

[Fallenangel]

I am running 16x8 / 15x7 (f/r) on my eg and honestly even tho it feels more direct than a 15x8 on the front, the 16in tyres have a slower compound than the 15in or 17in compounds.

That aside, I would not run a 17in front and 15in rear as the rear will be rolling around too much due to the extra height in the sidewall.

Also if you are looking at running a staggered set up, you do not want to run anything more than a 1.5in variance between front and rear widths.

For a DC5, we would most likely run a 18x10 front and 17 or 18x9 rear. We have found with the square set ups on lower speed tracks that they retain too much mechaical rear grip, causing the car to have a slight understeer tendancy. Good for a novice driver, but for those looking to get every last bit out of their set up, not so good.

On a DC2, to make 17x9's work, you will need to space the lower section of the front quarter panel, along with rolling and pulling of fhe front and rear guards. In turn, this will also require you to run a slightly higher ride height to allow for sufficent suspension travel

^This is exactly what i have done. Rose the car to 4WD height (pretty much), guards are pretty much rolled and cracked and spaced out 30mm. Minor rolling to the rear will fit a 17x8 +35 with a 225/40 tyre with no probs.