Track width alignment

[David Pozzi]

For max cornering traction the wider the better on either end.
On an autocross car, the width will hurt you on linked turns or slaloms especially.
Go-Karts adjust understeer/oversteer balance by spacers behind the wheels, widen the front track, more traction on that end.



As far as F/R track, I can't remember reading anything about it. making the front wider would affect tire scrub radius and the car wouldn't steer as well, especially going straight down the road. I think I'd try to keep the front as close to on center as possible. By on-center, I mean draw a line through the balljoints, where it touches the ground should be between zero and an inch inboard of the tire tread center. I don't have a definite figure, I just picked an inch as a number that would "sounds good" to me.

I don't think you want the rear way wider than the front, but if it were an inch or two wider I don't see any harm. The front has the most weight and would benefit from a wider track for better corner entry, but the rear helps you accelerate out of a turn and wider helps that.
In the end I'd make the tires fit the bodywork, try to make the front tires have a low scrub radius so it's easy to drive and brake without swerving around. I don't think an inch different backspace on one end or the other will be felt. On a go-kart it would since it's a larger percentage of the chassis width.

[JohnUlaszek]

Thanks David and Katz.

I need to keep working on that special valvetrain, maybe something bigger next time.....

Katz,
I keep forgetting you have a little Nova project of your own, any advice you can give me regarding balljoint location etc is much appreciated. Cutting up arms or moving things around is not a problem.

I am trying to get as much tire up front as possible, it looks like the Vintage Wheel Works V45 is limited to 4.75" backspace, hopefully this will allow the 245 up front. I don't mind working the sheetmetal to allow the widest tire up front as possible.

So, it looks like the 4.75" backspace is the driver here. The car is mini-tubbed and will have trucks arms so there is a ton of room out back to move the 285's wherever I want them. Appearance may become a factor. Ideally it sounds like I don't want the rear width any wider than front.

I will have a 2" engine setback in addition, so hopefully that will give the 245's up front a fighting chance.

[Salt Racer]

Actually, I'll be using JP IFS for my Nova and I didn't do any development on the car so to speak, so I can't comment much on the stock-based suspension.

But I punched in pickup point locations of G-mod'ed 1st gen suspension provided by David in WinGeo a while ago, and it actually looks pretty good save for bumpsteer curve. But I'm guessing you'll need some kind of drop spindles if you want to lower the car. I know mine was f'ed up, with subframe at 4" off the ground.

IIRC, the front outside sidewall-to-sidewall on my Nova measured about 69ish, while rear measured 70ish. 245s BFG Comp T/As (do they still make these tires?) measured 9-11/16", and 275s measured 11-3/16". So front track was like 0.5" wider than rear. I'm sure yours will end up about the same.

IF I were to modify stock IFS, I'd get a pair of custom drop spindles from SCP (since now I know they can make spindles with LBJ much lower than spindle pin), and build longer arms and use rims with more BS. Longer arms, better. Less scrub radius, better. The only down side is decrease in installation ratio.

But this obviously is not an option if you're set on VWW wheels. You could make something like Wilwood hubs (hub face is 3/8~1/2" closer to king pin axis), and make 1/2" longer arms, but that wouldn't be worth the effort.

Can you get 8.5" rims instead of 8", possibly with slightly more positive offset? (like 5.25" BS). That will helps reduce scrub radius, and wider rims make the tires work better.

[Salt Racer]

...Go-Karts adjust understeer/oversteer balance by spacers behind the wheels, widen the front track, more traction on that end....

Speaking of Go-karts, Brian Zales (baz67) and I went to an indoor kart track on Saturday. Within 3.5 hours, I spent more money than I had ever spent on a date (that's probably why I repel women). They have about 8~10 karts, and we tried almost all of them in an effort to find a good one.

Current track record is 22.22 sec, and I somehow managed 22.90 in a good neutral-steer kart


Sorry off topic. But, it's a really good for learning throttle steering so it's somewhat PT related.