Just a n00b

No backstory, just curious. I'm under the impression that it's bad since you lose contact from one of the tires, theoretically decreasing your overall contact patch. But I've heard people--who may not exactly be the best to talk to about this sort of stuff--say that if you three-wheel, it attests to the stiffness of your chassis and is a good thing.

dirty19

iTrader: (1)

I think if you search the forum you'll find many a write up by one of our members who is obsessed with this stuff.
Honestly there is absolutely no way to keep all four wheels planted.
Its something you can reduce by chassis set up but eliminate never.

Xian

Not true... you can eliminate 3 wheeling completely by going stiff enough in the front. Granted, you'll go more slowly this way than letting that inside rear skim just above the ground...

RR98ITR

"I see how you are".

Hey OP...there are people who think that front wheel drive race cars oughtn't lift the inside rear tire because bad things happen - things they presumably think worse than keeping as much weight as possible on the inside front - and that only anachronistically set up fwd cars do it. Like these clowns:

Scott, who isn't "obsessed"...so you must be talking about somebody else eh Paul?

PS - apology and appreciation to OJSantiago for reprinting his AWESOME shot.

Xian

Inconceivable!

RR98ITR

OMG!!! That guy painted his Rotors orange!

Scott, who is trapped in a bizzaro world of mixed up wheels and what they do and how they do it...all because a great motor makes them do it...

Xian

I asked for Mad-Skillz Yellow but ended up with Overdriving Orange.

powerneedy

who needs 4 wheels? lol

Robin6

Cherry photo!

dirty19

iTrader: (1)

Ok Scott so you arent obsessed but you like it alot
OP there are many threads created by Scott who is a subject matter expert on wheel lifting
Just search his screen name and enjoy all the reading.

I know i dont want to dial out all the wheel lift in my car so i just tricycle around the courses every now and then.

miamirice

Xian

And the less your inside rear lifts, the smaller the window of "optimum" grip balance you're likely to have... or at least that's how it works in my head... which is where I do most of my thinking about this stuff.

Christian, not a Sooooper Genius... someday maybe, someday.

ReDemoN

I noticed when my car did not lift the inside rear I had a ton of oversteer.
When I lowered the rear of the car some, I fixed the oversteer but now the inside lifts.
I like it better this way

RR98ITR

Right, but the stiffer the car is overall, the less the peak lift, necessarily. Lift or not, I expect the smart/fast guys to be maximizing the window of optimumity.

Scott, who didn't have what it took to be an actual genius...but had what it took to get an Honorary (?) "Sooooper Genius"...

dirty19

iTrader: (1)

just for clarification

Xian

And maybe the way to do it is via big springs and small bars up front. Or maybe it's no barz at all but probably not. Then what to do with the rear? Medium springs are good on the curbs which makes a big bar a requisite. But our diff wont work too well with the inside front in the air... I guess that's what we've got pimp shocks for, right?

Christian, who may or may not have a set of triples in his future.

johnjw

when our car 3 wheels under trail braking we totally smoke (flat spot) that tire. It sucks! Then we have vibration and what not. Our LR at the Ridge only lasted 10hrs before cords show. The RR however looked almost new, as it should.

I know this is more of a brake balance problem than a handling issue but something to consider.

gringotegra

3 wheelin here too!






That being said i also want to know what everything thinks on the 3 weeling.

Robin6

Xian

You could try adding more rear bar to get the weight fully transferred/off the inside rear or droop limiters. Also, if you can set up the car looser to begin with, you won't need (or be able) to trail brake like you're describing... problem solved, right?

<--- has driven LeChumpers that let you trail brake all the way to the apex... they also made square rear tires regularly. Loosened the car up, the square tires went away, and the lap times dropped as well.

Lo-Buck EF

I've gone Scott's way. My car does not lift an inside rear tire now. And I run up front and qualify on pole most weekends (not tooting my own horn. Just pointing it out).

johnjw

http://www.youtube.com/watch?v=fhtkZ...embedded#t=878

go to 14:35 for full effect :p

RR98ITR

Do you now? Do you really? You have NO IDEA what you're asking. The body of validated front wheel drive chassis knowledge is like an ember never quite alight and constantly at risk of seeming to go right out. Even Smart Professional Big Show Racing chassis specialists don't get it right most of the time - which is natural considering most of them don't specialize in fwd. Here's an example: http://www.f1technical.net/forum/vie...caster#p346112

GSpeedR, who I hold in considerable regard and who is my superior in many ways, repeats something Horrendous when he says that as soon as a wheel lifts the roll stiffness of the car changes. That's not as right as it sounds. The car with biased front/rear roll stiffness has two roll "rates" (in weight per unit time): front and rear. There is no disruptive change in the rate of front weight transfer after the inside rear lifts. AND it's likewise not completely right that rear roll resistance goes to zero as soon as the inside rear lifts. Don't believe me? If I'm not right, then at that moment you would theoretically be able to flip the rear of the car with your pinkie finger. Forgetting about gravity? Also, when that inside rear is up, the other rear tire should just be starting to slide.

Sorry - went off ranting a little. Back to your question Gringotegra: What does everyone think about 3-wheeling? They think lots of different things. And if you don't know how to separate noise from data then you won't get far. And if you do then you're farther ahead than most already. FWIW your pics from the inside of T9/12 look just about right.

Scott, who is still learning and I'm one of the most obsessed people on the planet about this crap...

VTECIntegra9

The thing with lifting an rear wheel is that it's more of an indicator to your setup. For example the dodge neon (Spec Neon still runs at my local track) they lift the left in every damn turn where they're not WOT...
To me it's an indicator of having the front end of the car too soft. If it had a higher roll stiffness in the front, then there would be less roll per G of lateral accel. If you take the torsional stiffness of the chassis front to rear you make the rear of the car roll with the front... the rear roll stiffness tries to reduce that roll also and can only do so much because the weight transfer is going to pull that wheel up as long as the front end of the car (because it is off-throttle, remember) has the most weight transferred to that outside loaded wheel... We've talked before about how the roll rate (degrees of roll per G's of lateral accel) increases the instant that the rear inside wheel comes off of the road. I'd have to re-visit that to understand again the theory but it made [some] sense... So that increased roll angle causes camber/contact patch problems in the front... This is why you want to keep it to a minimum. Due to bumps and our stiff chassis and trying to get them to rotate... we get some lift.

The reason I'm lifting the front in this picture (okay there might be some bumps in this corner but the chassis is still doing it's thing)... is the rear transverse-leaf rear end is too soft but we can't do anything about it without a redesign. So we have to loosen/stiffen the front springs/bar to balance the car... Much like a FWD car where it seems easy to adjust the rear of the car with big bars and crazy high spring rates.. I think the front would need attention first and then once the roll is brought down... then you balance the rear.

Or we can just drive the **** out of what we have as long as it's not a death trap and figure this stuff out later :-)

Lo-Buck EF

t5 at summit-

t6/7/carousel at summit



What scott says about the rear roll rate vs front roll rate is HUGE. How the car transfers weight when loaded laterally is a big part of this theory.