i recently installed some H&R RSS Club Sport coilovers, having previously had M7 springs. with the M7 springs and stock sway bars my mini had mild understeer, with just a touch of trail braking induced oversteer.

then i installed the H&Rs with IE adj camber plates up front. initially i set the camber at 2.5 deg all around (i do not have adj rear control arms). my car was so stiff that it didn't even lean in the turns AT ALL. it also pushed terribly. i figured that since it was not leaning, i should back off on the front camber. so then i tried 1.4 deg camber in the front and 2.8 deg (i lowered the rear a bit) in the rear. (i know 2.8 is too much, i am currently looking for a set of used urethane bushed control arms. BTW, anyone have some laying around?) now it was turning in. steering response was immediate. but, still pushing.

so, i thought, should i get a stiffer rear bar? how much stiffer can this car get. wait, how about REMOVING the front bar... sounds crazy, but with these springs rates, i think i'll be ok...

well it IS ok. it's GREAT! and... roll is still less than with stock bars and M7 springs! turn in is just a tad less razor sharp, but the front feels so much more planted. and the car is still "neutral" (in my view), meaning i can induce oversteer with the brakes, trail braking will pivot the rear around juuust enough. i can go front mild understeer to mild oversteer by modulating the brake/throttle. (i think i will try just a bit more camber in the front, since now it does lean a little, like 1.8 degress or so...) i get a little less inside front wheel spin. i also like the fact that both front wheels are now completely independent of each other. so, say going around a turn to the left and having the l/f wheel go over a bump. with a sway bar attached, when the l/f wheel goes over a bump, a force is transferred to the r/f wheel acting against the weight of the car (away from the pavement) causing a slight decrease in traction. with no swaybar, the r/f remains unaffected. .

anyway, i'm only posting this as an interesting experiment. i don't think most people will be able this. if you were to try this on a stock mini you would lean so far over that any handling benefit would be outweighed by very poor tread patch contact and very sloppy steering. but, if you have a very stiff suspension... hey, give it a shot. it's easy to try. all you have to do is remove one front link rod. that's it. the sway bar will not get in the way, it will follow one wheel up and down. yeah, i know, nitpickers will say that one side has more unsprung weight, which is true, but not much at all. besides, it's just to try it out...

i remember years ago on the VW forum there was a huge debate about this. one camp was no front bars. the other was huge front bars and even bigger rear bars. i used to be in the latter. now...?

anyone else ever try this?

 

The majority of tuning should come from the springs and struts/shocks... A swaybar is for fine tuning! The smaller the bar, the better...

 

I was thinking the same thing, but not as extreme. But really, it's a matter of degree. Massivly stiff spring increase roll stiffness, so you might as well back off the sway bars! Problem is, sorting this is a bit of a pain. I was thinking of trying the cooper front bar (not as extreme a change as you're making), I think Eric at Helix posted some racers were doing this that weren't allowed to make the rear stiffer. But choices for really adjustable bars or cheap options to choose from are a bit few and far between. Most options go from stockish to wayyyyyyy stiff!

Matt

 

i was also debating doing that. but it was really easy to just try no bar first, and i really liked it. it would suck to go through the trouble of dropping the subframe and installing another bar and still not be right. i say you should give it a shot, you may be surprised!

 

I installed the MC Spost Suspension (22.5mm) front bar a few weeks ago. My MC came with the SS+ suspension (24mm front bar).

The change has been very positive for my driving style. The main benefit is that on corner exit, I'm able to get more traction sooner from the inner wheel.

I'm a big fan of the change, and have now had the chance to autocross the car a few times in this configuration. I'm very glad I took the time to do the install (Randy Webb's how-to was spot on. ).

Dave

 

There are 2 trains of thought for a front swaybar on a stock class autocross car (where you are not allowed to change the rear swaybar)....

1) Go smaller because this will allow more traction on corner exit at the expense of body roll and slowing the car in transitions.

2) Use a BIGGER front sway bar, because this will aid in transition speed AND reduce body roll, which on a camber limited car like a Mini, means you'll have a better contact patch on the front tire. The bad part is that you'll loose grip on the inside front tire.

I don't think #2 will ever work on a Cooper S , since they already fight wheelspin too much. I know some people have been successful with #2 on HS Coopers, and I know some people use #1 on HS Coopers very successfully, too.

What I do know is, if you poll the really fast HS Coopers, you find a lot of variation in their setups. So in the end, I guess it doesn't matter! Myself, I just keep the stock SS+ swaybar on mine, because I'm too lazy to change it

 

Chris,
Appreciate your post. Your thinking makes perfect sense to me. Also, I have been thinking of using a MC front bar like Matt and others have suggested. There is the hassle of dropping the front subframe thought.

Will probably try you idea of removing a single front link and seeing how it goes on the track. A bit of an experiment. Will wait for warmer weather and dry track conditions.

Innovative thinking.

John Petrich in Seatttle

 

Less money... less time... and less weight (w/ no front bar or links)! Actually, Peter of M7 mentioned this to me darn near two years ago, and I never bothered to try it.

Thanks for sharing!

 

For anyone else thinking about this, but not quite ready to disconnect the whole thing (or that has and didn't find that quite to their suiting) there is also the option of using the 16mm Front Sway from the MINI ONE. Helix imports the MINI ONE bar here. It's not on their site as an individual item, however it is listed as part of their autocross package, and it is available if you call up Eric.

SS+ = 24mm
SS = 22.5mm
ONE = 16mm

 

I removed the front bar from my 1981 ford Fiesta. This was part of the advised European track setup thru BAT. A different car from a different time, but fwd, short wheel base yada yada yada - many identical layout features. The change was huge coming out of turns. The springs and dampers were designed along with the rear bar as a kit. So the engineers thought this thru.

The only downside was you had to keep your foot in it because the car could be prone to trailing throttle oversteer under some conditions. But on throttle it was big grin setup.

I don't remember anything about the rates or swaybar size...and it wouldn't be applicable given the Fiesta's 1,750lb weight. I miss that car...she was my first.

 

On my car i am using the H-Sport comp front and rear bars, the front on soft, with the rear on stiff. also a set of H-Sport Springs on Koni Yellows set to MED stiffness. i like this a lot. great at high speeds and turn is is great. (the added camber plates help that also)

i just added a 16mm front sway bar off a MINI One (from Helix) to a customers car here that autocrosses (down from a 24mm). (this bar will be up on your web site soon.) just installing the drop links to the bar would make the bar flex. so i knew the front was going to have a sloppy feel to it. i took the car for a drive and here is what i felt. driving straight down the road was no big deal, but if you tried to make a lane change or avoid something in the road, the car would have some serious lean and almost feel out of control. but this will totally be an advantage to a low speed autocross track. i also took it to a large parking lot and tried to do some turns like an autocross track would have, with a bit of speed. the car rotated nice at low speeds, so i am sure he is going to like it. and really the only reason he wanted to do this was because of the rules in the stock class. when i set my car up i wanted a good track car and fun for the street, with no reason to look at any rule books, so in the end who is having more fun?

but in the end be careful. there is a reason a front sway bar is on there, so any high speed stuff you need to make very small steering wheel inputs.

good luck

Chad
DT

 

Chris,

What are your spring rates from H&R ? I think it is important to know this bit of information to evaluate what you are saying.

Your post is thought provoking and has obviously sparked a lot of interest, especially from those of us who are running modified suspensions and increased spring rates.

Have had a minute after my initial post to re-read your post and think a bit. What you are describing about your chassis dynamics would be critically dependent on your spring rates, as well as your alignment settings, tires and other factors.

What's the scoop?

John Petrich in Seattle

 

Well, let us know what his tires look like after a couple of events To me, this sounds like a recipe for understeer, since you're leaning so much that you can't maintain any contact patch on the outside front tire.

 

if you increase the spring rates, you up the roll stiffness. You can drop the sway bar stiffness and still have the stock roll stiffness. So, any clue what the spring rates are on the cars we're discussing?

I'm running 325 lb/in front and 350 lb/in in the rear. But I don't know what the stock spring rates are. Anyway, I'm sure I can drop some bar stiffness and still have good lean in corners.

In concept, there's nothing wrong with this kind of suspension sorting. Adding some spring rates would help shed light on the discussion.

Matt

 

i'm afraid i do not have the spring rates. they are H&R Club Sport, so maybe if i contact H&R they could tell me. i do not have time right now as i am at work. all i know is they are very stiff. like i mentioned, i would not recommend this for a car that was not already quite firm in the front... .. that came out wrong... otherwise it would lean too much and you would loose your quick turn in ability. like i mentioned, i DID lose a little, but it was still more than with my M7 springs and stock front bar.

i hope that helps, but i do not have the rates...

 

front camber 1.4 both sides
caster is at 4.7 left, 4.2 right
front toe is 0.10 deg toe in (each wheel)
rear camber is 2.8 both sides (too much, need arms...)
rear toe is 0.20 deg toe in (each wheel)

the car has been lowered a bit. the front is about the same as my M7 springs, maybe a little lower (lowered about 1.5 inches?). the rear is about 2 inches lower (top of tire is just barely visible under wheel arch).

hope that helps.

 

Chris,

Thanks for the detailed response.

Understand your problem about quoting the spring rates. H&R is always very vague about their spring rates. I've telephoned them before and gotten little satisfaction. They advertise your set up as "the stiffest" they offer for street / track use. Don't know what to make of that. You characterize them as "stiff" enough to notice. I'm running 250#/inch spring rates and do notice the stiffness, some. Great for me, but close to the max for a consumer oriented street product. Matt is running 325#/in and 350#/in and don't know how "stiff" he'd characterize them. The stock springs are estimated by some to be in the 180#/in range. So, we can make a very rough guess that the H&R spring rate is "around" 250#/in.

There was the exact same thread this past Fall on our local Puget Sound BMW CCA Chapter website. A number of local racers and builders contributed and articulated Matt's position. Matt described that the roll is resisted by both the springs and the anti-roll bars (a.k.a. torsion springs). Increased spring rate will allow a reduced anti-roll bar rate to maintain the same roll rate (degrees / G of lateral acceleration). The BMW oriented racers who posted reported having implemented any number of combinations of no, medium and high rate front anti-roll bars all linked to spring rates. A number advocated no front bar with an adequately sprung car. So, Chris' observations make a lot of sense.

On the street with street tires, but higher rate springs, the anti-roll bar delete option would improve the ride and not make much of an objective handling difference. Most road irregularities, by a large margin, are not symmetrical and the anti-roll bar is almost always adding to the effective spring rate. So the ride will be 'better".

In the Autocross "reality", we've been told how less front roll resistence with stock spring rates affects things. Autocross with increased spring rates would probably work pretty well with the front anti-roll bar delete option.

Regarding the track "reality", all bets are off. The result will depend on driving technique, alignment as Chris described, chassis stiffness, tires and other variables, hinted at by Michael, that I cannot think of at the moment. I think that some experiments are in order. If I were to delete my front anti-roll bar and with my 250#/in spring rate, I'd expect a greater tendency to oversteer, only a slight reduction in my already miniscule roll rate, less inside wheel lift at "track out", and generally improved tire / track surface compliance. (our local track is notoriously "rough")

That's enought. I'm obviously thinking about this one.

John Petrich in Seattle

 

When you figure it all out, let us know! That will save the rest of us some time...

And FWIW, the 325 in front are just a hair firmer than I'd normally do for a street car. The 250s were too soft for my taste.... But then, that's me.

Matt

 

about the spring rates... if the stocks are 180lb/in then these are easily twice that, if not more. these things are VERY firm. the rss club sports are one step from all out race coilovers. the fronts have 5 coils, and about 3 of those are dead coils. the rears have 8 with 5 dead coils. i tried to push down on my front bumper to "jounce" the front and i swear it didn't even budge. with the M7 springs i could maybe get 1/2 to 3/4 inch. with these...nothing. just a crunchy sound from my bumper cover from me pushing so hard!

 

I'll be replacing the PSS9 front springs (progressive, I think up to 325) with H&R linears, 350's. The rear will remain with the PSS9 linear springs, at 340 or 350 in-pounds...

I will try disco'ing the bar shortly after that time.

Funny, while checking for a previous post from myself regarding the PSS9's, I found this: https://www.northamericanmotoring.co...6&postcount=48

Look forward to hearing input from others who try this...

 

...I think you can work backward from a known or existing wheel rate since this is a combination of spring and bar - all else off the table. Remove the bar's contribution and you'll get an idea for how much less wheel rate you have left.

You may find that mechanical grip improves a little if you can manage camber changes with a smaller wheel rate - more lean = a potentially less optimized camber curve - at the limit.

Of some consequence here is offset or wheel spacers as these two will affect camber strength to some degree because these affect the literal path or curve the tire follows. So I think you have to look at many things to be sure you can take this in the right direction...simply removing the bar is the first of many steps, but do you turn right or left after the bar is off?

...another thought relating to the above paragraph is track width and motion ratio. If you are autoXing and that is directing the majority of your decision making, you can decrease track width up front relative to the rear. This will improve motion ratio - spring rate will increase, and the Ackerman angle will also benefit aiding turn-in. As John wrote, these last few suggestions are probably the wrong direction if you plan to drive on a road course most of the time.

And finally, keep in mind that as spring rate increases, spring travel decreases for a given length spring; if you double the spring rate check the springs travel against what you need. You may find that you have to jump up in length...the coils are larger and consume valuable travel as the spring compresses. Megan increased spring rate in an attempt to fix a shock/damper travel deficiency. The rate went from 285 to 469. So the higer rate ostensibly corrected travel related problems, but in reality, spring bind caused the same condition because they used the same length spring.

All these problems seem to take place in the last inch of travel, think about that for a while...

 

i don't see how increasing the track will affect the spring rate on a macpherson strut suspension. a 1 inch compresion of the suspension equals 1 inch of compresion on the spring. it's a 1 to 1 ratio. increasing the track will not affect that.

also, track will not affect the ackerman angle, which is drawn from the kingpin, or steering axis in our case, to the centerline of the rear axle. moving the wheels in or out will not change the steering axis, only the scrub radius.

and what did you mean by turning left or right?

 

Increasing track absolutely affects motion ratio, and hence the the phrases reason for being. This is a simple lever arm calculation; Inner pivot point to damper mounting point is a given. But if the length from the damper's mounting point to the tire's centerline is changed, spring and damping forces will be affected. For example, adding a 15mm spacer will require adding 7.5% more spring rate to keep the spring rate identical to the rate sans the spacer.

Also, control arm movement and damper movement are not linear. The only way these can be linear is if the damper sits over the tire's center line. One of the reasons folks complain about deteriorated ride after dialing lots of negative camber is that as the control arm moves up - hitting a bump - the damper's stroke increases in velocity. In other words, at some point the damper's velocity is faster than the control arm's velocity.

I meant to write scrub...SAI is only altered if camber is changed.

...turning left or right is a philosphical question. When you remove the front bar you can take a road that enhances what you've done, or one that makes things worse.

 

forgive my crude diagram, but my point is that you can't gain any mechanical advantage on that lever system by grasping the bar further away from the pivot. you still must move the bar the same distance compressing the spring, no matter where you apply the force. am i missing something? not trying to be a smartass, just would like to understand what you mean. maybe i'm missing something...

i would also like to add that i like this thread and don't want it to get too far away from swaybar/no swaybar and pros/cons plus personal experiences of either set up. so things like track and such would affect a car whether or not it had the swaybar connected, so i don't want to delve to deeply into that.

of course by posting this, i am only exacerbating the problem... eek. oh well.... here we go!

 

Chris,

You are not exaserbating anything and nor are getting off your topic. Your topic is deeper than you think. It is impossible to touch anything and not affect something else.

Using your diagram; if we assume it takes 500lbs of force to move the control arm up one inch where the first arrow is, ( remember that in physics, the road pushes back up on the tire, so the road's leverage is part of the equation) it will take 250lbs of force to move the control arm up one inch if we double the distance - inner pivot to the first arrow is x and inner pivot to the second arrow is 2x. Lever equations are linear. Motion ratio calculations were developed for this very reason, to help tuners figure out leverage changes. As the lever arm increases (track width), spring rates need to increase.

The moment you begin to discuss leaning and spring rates and the absence of a front swaybar, the door automatically opens to other aspects of tuning that WILL affect how your car handles. And some of these other areas offer opportunities. I throw stuff out there all the time hoping that the folks reading latch onto some of it and use it to there advantage, or, realize that a seemingly simple mod has much larger implications.

I'm not challenging your goals here. As you have read in my first reply above, I did the same thing on one of my cars in 1981 - 25 years ago and it worked quite well...luckily physics has not changed much since then...black holes are not an immediate concern. So have at it, I think you're onto something that will work. But you have other ways to enhance what you've begun, the very reason for my reply. And I added the information about spring rates and lengths because so many either forget this or do not know it.

There is very little change with regard to the Mini's rear suspension since the double link setup has such a long lever arm - in this case the instantaneous center is the pivot point/fulcrum.

Ackerman is changed when offset is changed too. It has to since the the tires/wheels are hung farther out or pulled closer in to the car's center line relative to stock.