In the June issue of Automobile magazine where they review the 05 MINI S there is a picture of an MCS cornering that shows the inside REAR wheel coming off the ground. I presume this was a stock MCS (they didn't mention anything to suggest otherwise).

My question is, if the stock rear anti sway bar is already stiff enough to cause the rear inside wheel to lift off during cornering, why would one need an aftermarket bar?

(I thought I understood the principles behind antisway bars and why people go for (stiffer) aftermarket ones until I saw this picture!)

 

If it is a stock MCS, then they would have to be very heavy on the brakes to get the wheel to lift. The aftermarket swaybar will cause the wheel to lift with less braking (on none )

It's all a balancing act. The stiffness that will cause the MINI to corner neutral with no throttle will oversteer off throttle and understeer on throttle. The mose stiff the rear swaybar, the more it pushes the limits towards oversteer. This is why the most stiff setting on the larger bars are intended for auto-x as you can keep the foot on the throttle through the corner and the bar will keep pressure on the front tires.

 

I would expect the rear wheel to come off the ground in very tight corners - on or off throttle. The rear swaybar is stiff enough to lift the rear wheel while jacking the car from the front jack point - not a scientific observation. This is part of the Mini's tight cornering character like so many VWs.

Yes, a larger rear bar will add to roll stiffness and has the potential to cause the rear wheel to lift sooner while cornering. BUT! This depends upon many other variables for which the permutations are endless. By contrast, the rear inside tire on my 99 Si with a 25mm rear bar does not leave the ground while cornering, but does while jacking from the front jack point. Different cars different set-ups etc.

 

I don't think I've ever lifted a wheel on the Honda. Nobody has shock travels during one of these experiances do they?

 

Thanks for the replies.

OK, I think the key thing as kapps said, is that the photo must have been taken under strong breaking during cornering. Otherwise, why would the MINI (stock) understeer in this situation (if it were "normal", i.e., no strong braking) with more traction in front (two wheels) vs the rear (one wheel).

 

In theory he would be loose in that situation. When you lift a wheel you lose half of your contact patch. Now the VW's and apparently some Mini's are the exception to the rule.

 

...and Ford Fiestas. I was able to get the inside rear wheel off the ground on my VW and Ford Fiesta under power in tight autoXing environments. Like Orthomini Jr. wrote, never in a honda.

Among the many differences between these cars, the standout is suspension type. Most Hondas employ a double wishbone suspesnion. This allows the suspension designer to lower roll centers and maintain their movement with a bit more accuracy. A higher roll center will in theory allow a back end to 'kick over' its roll center with a little more ease and drama.

In the end, there are many aspects that define a great handling car. If the Mini's lifting inside rear wheel is a liability, other portions of the Mini's character more than make up for that drawback. It's still one hell of a driver's car!

 

Somewhere I have a picture of me autocrossing my friend's stock class Integra Type-R in a slalom, and it's on 3 wheels. I also have pictures of my Civic EX on 3 wheels through a sweeper - and it doens't even have a rear sway bar. So Hondas can lift a rear wheel in the corners, but certainly not as profusely as a VW will My '88 GTI would lift the inside rear wheel almost over the cones!

ofioliti - people put big rear swaybars on VW's, too, and if you look at that rear suspension, it basically already *IS* a big rear swaybar with a couple wheels hooked to it

The rear end is a lot lighter than the front, and doesn't need as much traction, for one thing. . . Vw's really lift that rear wheel, but will still understeer.

 

 

um... sorry to burst your bubble but...


Oh, forgot to mention it's an aftermarket swaybar

 

My bubble is not burst. I've never lifted a rear inside wheel in my Honda.

Indeed, there are many factors that can contribute to this phenomenon not the least of which is roll center, and, its realtionship to the center of gravity, and, what G-load threshold will cause each car to lift its inside rear wheel, roll stiffnes...the list goes on.

Cornering on four wheels is faster than three. Therein lay a compromise between roll stiffness, balance, and pure cornering force.

...a little more; once the inside rear wheel lifts off the ground, rear roll resistance has contributed 100%! This means that any additional roll resistance must come from up front. After the rear wheel substantially leaves the ground, roll angles increase rapidly and the car will understeer. I prefer to set my car up so that I can get as much rotation as possible without lifting the rear wheel because...I can deley or prevent understeer...and, usually the rear wheel is still off the ground while appraoching a straight...and, exiting out of a straight with authority requires lots of traction...this is more obvious in a rear wheel drive car, but four wheels on the ground while exiting a corner in a front driver is more stable...take a fast sweeper on three wheels...bring toilet paper...and, just in case the reader points me to a Kart with its inside rear wheel off the ground...no differential, it needs to lift the inside rear wheel in order to achieve rotation. I may not be able to prevent the Mini's inside rear wheel from lifting, but my eye will be focused on it during my trials and final set-up.

Onasled, you startin trouble...dat ting is on two wheels, c'mon now! If that were me driving, you would have heard, "oops" or some other unprintable superlative.

 

wow...thats all i have to say... continue on as if i never posted...

-Josh

 

Sounds right to me. My Cooper has been seen on three wheel very brielfy. Sounds like my thought might be right that a stiffer front swaybar would bring that wheel back onto the ground.

Is it time to start playing with balancing my front and rear swaybars?

How much of a difference in there between slow / tight autocross corners and faster / larger radius track corners? Are we more prone to three-wheeling on an autocross course? If you remove that tendency on the autocross course, might you be hurting your track handling?

My setup is JCW suspension, stock sports suspension front swaybar, and RDR rear swaybar on full soft.

 

At NHIS and also Lime Rock, I will tend to pull the inside rear tire off the ground. In this last video I was told that this was happening to me on occasion in turn three (the one that I have to shot from outside the car)

I truly respect MEB's knowledge here, but I sometimes don't find the same conclusions. Lifting the inside wheel does little (of course this is IMHO ) to inhibit handling. The fact is that the contact patch of an inside wheel on a FWD car in the same turn is not much more then a book of matches. I find no ill effects of doing this, and in fact I usually don't even know it's happening.

Not much of a cure for this in a Mini. Putting a stiffer front bar on would only bring back more understeer. To neutralize this understeer you need to stiffen the rear bar (exactly where I am at), and then the rear wheel gets pulled up that much easier.

OK Michael, how about this one then .....

 

hehehe, nice try, but that guy hit the chicane.

 

A lot of them did .. http://www.wessexnetworks.com/jccgal...photos/2005/75

 

slowly .. beginning ... to ... understand ....

Interesting stuff.

OK, another related basic question that has come up because of someone's comment earlier:

Other things being equal, the more weight towards the front of the car, the more understeer? Is that correct?

(Initially, this seemed counterintuitive to me because I was thinking "more weight on the wheels, more traction." But then thinking about it more, the front wheels are trying to make that weight change direction during a turn, and thus having a harder time.)

 

Anyway, lifting a rear tire in Minis and VW's is fun!! Great notes above!

 

I'd be willing to bet that if the guy int he blue had his shock travels He completly bottomed out the right side. When he did that, the suspension looked for more travel and found it, by lifting the Left side. Some poor guy in a street stock car did that in 1 & 2 at Talledega short track and rolled it.

I prefer to use all four tires

 

Stold this from epeterson where he posted race update

 

Onasled, I appreciate the compliment. Thank you.

I don't have much time today, so here goes.

It is no surprise that some of us will find different solutions to similar handling problems. I personaly find this type of environment exciting - I get bored with my own thinking after a while.

I think it is important to seek out and follow thru with ideas within one's own realm. However, I think it is equaly important to discuss differing ideas, opinions, and, experiences. I find this grounds my thinking. If I appear to challenge some thinking here, it is not say I am correct...quite honestly, I'm searching for other ideas from you.

You must also appreciate that when we as a group begin to explore suspension tuning modifications, we make some assumptions based upon what we know, what we can afford to do with regard to time and money, and, where our cars will be driven. Therefore, there can be no perfect solution. for example, once I commit to the PSS9 system, I am limited to some degree to what I can achieve with my Mini. If I were to contact Bilstein or Koni or Leda and go down the path of complete customization, I would probably have more tuning control/options...at the expense of time, money and comfort.

By simply adding to the commntary, I'm hoping to trigger thinking. some of my suggestions are applicable to some, based upon their assumptions, but not to others.

Okay, enough metahpysics. I believe that I can control inside rear wheel lift to a greater degree with spring and dampers, rather than with a awaybar. But! I would probably not like the ride much on public roads. I don't know if I can eliminate this condition...and if I do with repect to the Mini, I may have a poorer handling car on my hands. Dunno??? The Honda sitting outside my office is currently stting on 400lb/in linear rate springs up front, 600lb/in linear rate springs out back, Show Room Stock valved Koni adustable dampers, stock front bar, 25mm rear bar, adustable upper control arms front and rear, poly and hard rubber bushings everywhere and this list goes on. This car is brutal on the street and still too soft on the track - a horrid compromise. In other words, I didn't get this one right. Yes, in some conditions it is a wicked accomplice. In others...well, I ask myself, what did you do Michael.

Apply my experiences and thinking with caution - do not supplant or de-value your own thinking as my goals may be quite different. Thomas Edison once wrote - not verbatim - "I tried to make a light bulb 2,000 times before it actually worked. I can now tell you 2,000 ways not to make a light bulb." Sometimes experimentation should be nothing more than asking this question to one's self, "what of I do this?" - with no outward goal or agenda. If you follow the leader, you'll never be a leader.