After Blyton looking round the cars I wanted to ask your opinions on rear anti roll bars on a mini.
I can't see the point or advantage. Unless you were running a Hydrolastic car.
When I see cars on track taking a hard corner with one rear wheel in the air, (even Pete's hornet is pictured on three wheels ) surely even although it is the lightest corner, you would still gain some grip advantege with the trailing wheel on the tarmack.
So I'm thinking in this situation the front corner is set too soft allowing the car to nose dive lifting the rear ?
What are your thoughts ? I am probably barking up the wrong tree ?
It's a hard one this, I've always had a Janspeed one on the back of my hydro car, this has recently been replaced by a KAD road version (I changed the exhaust and the Janspeed one wasn't going to fit comfortably) the KAD bar has stiffened the rear more as it's a bigger diameter, when I use the car for hillclimbing I don't want the rear wheel to keep dropping and causing the helper spring to stretch, I've never had one on a dry car as ultimately the wheel will only drop as far as the shock absorber shaft will let it (though this probably doesn't do the internals of the shock any good)
As for the wheel lifting and reducing grip, that's exactly what it's there to do,(no offence to anyone as I'm sure you are all aware of this already) with more oversteer at the back it's counteracting the understeer at the front so you can turn the car harder.
I've not had a chance to test the new bar on a circuit yet, and due to some other issues with it I'm not sure if I will competitively this year, but this is when I'm expecting to feel the most difference over the old bar
IAIN wrote: surely even although it is the lightest corner, you would still gain some grip advantege with the trailing wheel on the tarmack.
As Mark explains above you want to loosen the rear not have more grip , you can then steer the car from the rear as you're hard on the throttle. I have to admit my car was set a little soft on the front (didn't finish playing with it due to brake failure). Also depends on the camber of the surface the degree to which the tail will lift. I didn't feel a spin coming on at any time with my set up and in fact really could have done with a little more oversteer.
AIUI... a roll bar acts to transfer weight diagonally across the car. A rear bar acts to load the inside front wheel. You want to increase front grip..not reduce that at the rear..
I have never driven a mini with an anti roll bar but thought stiff front shockabsorbers would be enough. With the rear shockabsorbers set firm the inside wheel won't drop in a hurry any way.
I supose it all depends how stiff you can get away with setting the shockabsorbers and what type surface you are running on.
I drive my minis VERY hard, and I am from the school of thought that a rear anti roll bar is a great thing. I know Vizard and Trickey are indifferent about them, I disagree, they "make it right" and here is how.
Bear in mind, I took the hydro off my 66, as I wanted a Mini and not a Citroen BX. I found the Hydro (with ST displacers) unacceptable. My mini runs on NOS Pre 64 dry cones (which are more resistent than the later sort), they are also more linear in response than the reprofiled racing ones (with more of an exponential response).
I spent a lot of time tuning my suspension to make the car handle better and I fitted a roll cage, purely to stiffen the shell up and make the suspension settings "work". You can't have all this superduper adjustment and then you fly around a corner and the shell twists in response.
Understeer is the enemy and there is only so much negative camber and sticky tyres you can get away with. The ARB makes the car flatter through corners and it understeers less as a result.... you don't get so much of the feeling you are piling all the weight on one wheel, which then starts to slide. If you throw the car, because your inner rear wheel is barely gripping, you can get a nice controlled 4 wheel drift. It will show up any errors in your rear tracking with either irritating (tow in) or frightening (tow out) results.
It is much more than degripping the rear, it does help the front to grip and also allows you to run the suspension lower (concentric within the arches for me).
I find a 12mm fixed rear bar the magic medicine for my mini and is the best upgrade I made to the car and one of the first things I'd do when buying another mini.
I have an anti roll bar on my car and running coilovers and yoko a048's I cannot get my car to cock a rear wheel. I was coming out of the bend onto the runway at 60mph fit flat to the floor all the way round and on the photos the pro took, my car was level as a radiator in your Livingroom. I love the feel of my car though some might say is to hard for the road, but it's just a toy.
Rear anti roll bars are down to useage and personal preference. In a hard driven car the rear comes out easier going into a corner and seems to stay in a more stable slide under power, but what happens if you have to lift off? Probably best left to competition use, but there again personal preference.
I've got no bar on my race car but I have rear arm travel-limiting-rods, which seem to do a similar thing but they are much lighter. It readily lifts a wheel and that is helpful to steering the rear. I am still out on the decision and I should probably try an ARB one day to see what it does.
An interesting thread this one as I have been considering a rear bar for some time myself.
My understanding is they are used to reduce roll, therefore allow the car to corner flatter by using the combined mass/spring rate of the inner wheel to effectively stiffen the spring rate of the outer wheel. When both wheels are raising and dropping at the same speed it should not have any effect. My thinking was fitting an ARB would allow me to run softer settings for a better ride without the huge tyre on arch scrubbing load on the twisty bits.
For me, I am simply going to try one and see what happens as I think handling is as much about confidence in the car, and this is a personal thing.
I would be keen to hear any thought about front ARB's
sr001 wrote:My understanding is they are used to reduce roll, therefore allow the car to corner flatter by using the combined mass/spring rate of the inner wheel to effectively stiffen the spring rate of the outer wheel. When both wheels are raising and dropping at the same speed it should not have any effect. My thinking was fitting an ARB would allow me to run softer settings for a better ride without the huge tyre on arch scrubbing load on the twisty bits.
A good part of the equation is to use one rear wheel only (outside) on hard cornering, allowing that wheel to "steer" and taking advantage of any toe-out and negative camber. This can be done with an ARB or with travel limit rods like are on my car.
interesting............. any more thoughts.
