Lifting right front wheel

[Oh Haha]

Not me.
I watched some club racers at Gingerman this weekend. WOW!!
One car, a 80-88 Carrera/SC, would carry the right front all the way through the right handers. Pretty cool to see but why would the car be set up like that? Seems to me it would hamper the control. It didn't seeem to bother this guy, though. I didn't get a chance to track him down after the race and ask him.
Thanks for your thoughts, guys.

[Dantilla]

I'm told I lift front wheels when autocrossing quite a bit.

Common for early 911s to do that. Most of the weight is over the rear. Even the factory racers would lift the inside front. Nothing to worry about.

[Gumba11]

Common on older torsion bar cars. The inside tire would be more useful on the ground. ERP has some snazzy suspension items that can take care of that for a $$$. Though it is expensive it is amazing stuff. I have 935 spring plates and mono balls for the rear of my 930 that I am very excited to install soon!

.................................................. ....C

[Steve@Rennsport]

Hi:

The main reason that 911's lift their inside front wheels in hard corners is due to insufficient rear stiffness.

One adds bigger rear torsion bars (springs) and a stiffer or adjustable rear swaybar to fix this. In some cases, we raise the front spindles on the struts (Bilstein only) to raise the front roll center to reduce lateral weight transfer.

Without question, "4-wheeled" cars corner at a higher speed than "3-wheeled" ones,..... :

[Jack Olsen]

I always agree with Steve. But I agree with him only up to a point on this one.

My 911 has 600# rear coil springs, a 23mm SRP rear swaybar, and the SRP alternative rear trailing arm mounts. The car lifts the inside wheel less than it used to, but it still does it.

I'm happy to say that (thanks to guys like Steve) my car corners better than most "4-wheeled" cars.

You want to reduce this lift, in my opinion. But I wouldn't obsess on eliminating it entirely. Formula 1 cars lift inside wheels and they still corner pretty well.

It was recently discussed in this thread.

[NoLift911]

Originally posted by Jack Olsen
"I always agree with Steve. But I agree with him only up to a point on this one. "

Ha - interesting. I always agree with Jack - but disagree on this to a point...

You need all 4 on the ground. My buddy and I were arguing about this a few weeks ago at the track. Aside from the cool factor the wheel cannot do it's job hanging in the air. Just like with 4 wheel drive vehicles - axle articulation is key for traction and what all off roaders strive 4 - keeping them all on the ground.

Think how much better cornering would be with the added grip of that one wheel in the air - how much deeper you could drive in and how much faster you could exit out?

Maybe some of those F1 cars were not setup properly - or could be setup better or just setup to suit a particluar driver. We all setup up our cars that best suit our tastes and there are compromises in certain areas (such as inside tire lift)

Wonder what would happen if the car was setup to eliminate that characteristic - would you still hold the same view after a few laps around the track? Even if money was no object?

And yes I agree - not much to get too worried about. Each car has a characteristic that makes it unique just like the rear wheels on Dodge Neons and A2 body style V-dubs.

-Jeff

[ZOA NOM]

Corner Balance.

[island911]

Well I'll disagree, to a point, of a disagreeable point of dis . . ah where are we?

Say you get all four to touch; Just how much work will that barely loaded wheel be providing? How will the toe angle be contributing (helping or hurting) with next to nothing of loading?

So, what I'm getting at is, I think that this is not a linear (or binary) issue. I'm speculating that just having the 4^th wheel touch will NOT suddenly start adding more cornering force. (it will be a transient thing . . .until the 4^th is properly loaded. ...properly aligned for the conditions)

[chrisp]

Don't forget the size of the tire sidewall in F1. Most of that lift comes from uncontrolled compression of the diagonal rear tire. In addition to the miniscule down travel those cars have it's easy to lift the front.

[Eric Coffey]

What F1 cars you are speaking of? I have watched almost every practice, quali, and race this season and have yet to see a modern F1 car "up on three" at any circuit (without the aid of the curbing). The closest I have seen in the common inside wheel lock-up under braking. If your inside wheel is visually off the surface, the car (set-up) needs to be looked at IMO.

[jluetjen]

Originally posted by nolift911
Originally posted by Jack Olsen
Maybe some of those F1 cars were not setup properly - or could be setup better or just setup to suit a particluar driver. We all setup up our cars that best suit our tastes and there are compromises in certain areas (such as inside tire lift)

100's of employees, 10's of engineers, Millions and millions of $'s. You're saying...

*

I assume that you've taken the time to roughly calculate the load transfers on a car with a 911's weight distribution and CG? Do you know how much load would be on the inside front tire -- even if you could keep it on the ground with suspension changes? The practical reality is that most suspension tuning is about trying to maximize the performance of the outside wheels (as well as the inside rear when accelerating and to a lesser degree the inside front when breaking) since they are carrying the overwhelming majority of the load, and are generally limiting the maximum cornering speeds.

(* I've been dieing to use that smiley for a long time. Now an inoffense means! Thanks for the opportunity).

[ZOA NOM]

It seems to be pretty basic math and physics to me. More tire on the ground = more grip = faster cornering speed. It's why there aren't any trikes in F1.

[911pcars]

I concur with Eric. From my recollection of current F1 races, the only time the inside front wheel is in the air is when they're short-cutting over the corner berms.

Sherwood

[efhughes3]

Guys, guys. Read Island's post again! He is right on the money, IMO. If the tire was touching, it would be minimally loaded.

[Dantilla]

My car lifts a front when at max acceleration coming out of a corner. I'm already at or past the apex. If I'm already at max acceleration, and staying on the proper line, I don't see what difference it makes. I'm not lifting when cornering hard.

[emcon5]

Originally posted by ZOANAS
It seems to be pretty basic math and physics to me. More tire on the ground = more grip = faster cornering speed. It's why there aren't any trikes in F1.

Hmmmm.




But we aren't talking about F1, are we.

Whip out your slide rule and tell me the basic math and physics of why I run the rear tire pressure at ~50 PSI cold on my race car to decrease rear grip, even though it does this in almost every corner:



BTW, this is yet another subject that has been beaten to death. In my opinion, the best of the 5 or 6 threads covering front-wheel lift is this one:
Why lifting a front wheel is bad

John sums things up pretty well:

Originally posted by jluetjen in another thread
Now admittedly, adding weight to a tire while cornering produces diminishing returns which is why if you can keep the inner tire on the ground and get grip from it, it will help that axle get more grip. But in the case of the 911, it's not the front axle's grip that is limiting the cornering potential, but the rear end's grip.

Tom

[911pcars]

"...If I'm already at max acceleration, and staying on the proper line, I don't see what difference it makes. I'm not lifting when cornering hard."

Sounds fine in your case, but what if you had a 1/2" more pedal to push, and if you could, your slip angles might lead you off-track? Back to the basic assumption that 4 contact patches are better than three while cornering. An urban myth?

MHO,
Sherwood

[911pcars]

Tom,
Thanks for the opposing evidence. I guess I'm not so observant during the early morning F1 telecasts as I pry my eyelids open. However, does this fact signify a design element that chassis engineers strive for or an effect they wish to minimize? I think this phenomenon occurs during low and moderate speed, acute-angle corners. I don't think they want to see this happening at all during max. G, high speed corners.

I'll bet if they had their druthers, they'd prefer all 4 planted as the machine rolls around the circuit.

Sherwood

[chrisp]

Interesting discussion and interesting how we think F1 has ideal car set-ups. Again, their set up is a huge compromise given the tires they have. I am sure they would run a much lower aspect ratio if they could. Then front wheel lift would probably go away. We would all be saying "if F1 cars have no lift then my 911 with lift severly compromises grip."

I see F1 as having the ultimate technology, largest available dollars, and organizations providing the most resources for perhaps the largest accumulation of the brightest engineers (per team). I wouldn't categorically say that we should emulate everything they do.

[911pcars]

This link is one in a series of cornering articles. This page describes what causes the inside tire to lift.

http://www.turnfast.com/tech_handling/handling_antiroll.shtml

Sherwood