: How to stop the inside front wheel lifting??
Dec 6th, 2008, 07:02 AM
When doing a recent track day the biggest problem I had with loosing time was on the sharp hairpin bends. The inside front wheel had a nasty habit of lifting & spinning :(
Now I know an LSD would make traction a lot better in these bends but if I don't have that sort of cash I wondered how to flatten things out a bit. I have just fitted some KW springs which has given the car a more aggressive stance but I believe some chassis stiffening will be in order. I'm sure if I fitted both front & rear strut braces as well as rear, centre & front ARBs it would corner flat as a pancake but which of these or which combination of these would go the furthest to eliminate this problem?
Dec 6th, 2008, 10:02 AM
Fit the upper and lower front braces, then rear, apparently the 2 front braces combined are vastly superior to just the top brace.
GTT do a package price for all 3 braces that was in last months Modern Mini Magazine, around the £500 mark, not the cheapest, but certainly worth the extra from what most people have to say
Dec 6th, 2008, 11:28 AM
The strut braces will have little or no effect , the front spring rates and rear anti roll bar will dictate wheel lift
Dec 6th, 2008, 12:28 PM
whiteline do a nice rear arb, 3 way adj,
i think minimania can supply these?
Dec 6th, 2008, 01:08 PM
The strut brace stiffens the chassis , think of a box with no top on it ,the brace forms a top
having the brace reduces movement of the strut tops ,on to which the shock/springs are mounted - if the strut tops move in or out during cornering with weight transfer it changes the angle that the shocks are at - this alter the geometry of the suspension
the angle that the shock is at is part of the calculation for the spring rates so in effect they change during cornering - this change along with other effects is why you feel the difference when the brace is fitted
Dec 6th, 2008, 02:20 PM
So having the bottom brace too doesnt help at all Adam, or just in this scenario ??
Dec 6th, 2008, 02:42 PM
The bottom side of the square is also a hole , but has the x member bolted across- an x shaped piece of metal which forms another side of the box , the engine itself also act like a brace in the middle
The lower brace helps stiffen these two but has a far less effect IMHO
keeping the chassis ridgid is the aim thats why the race cars have a roll cage bolted/welded in
The rear strut brace is questionable as to its usefulness except in the convertible ,but I have seen dents appear in the roof of track cars so something is moving!!
Dec 7th, 2008, 12:10 AM
So what you're saying is that the first port of call is a stiffer rear ARB?
Dec 7th, 2008, 06:23 PM
Simple answer is yes
This is not my strongest automotive topic but I will try ;
When the car goes into a turn the weight moves to the outermost side of the car and it rolls
two things act against the rolling 1 the stiffness of the springs and 2 the ARB
the combination of 1 and 2 at the front of the car and the rear of the car will give you the total roll resistance of the car
the total roll resistance as you can see is rear and front added , but how much roll is transfered at the front and how much at the rear can be adjusted -- by either using stiffer springs or a stiffer ARB or the opposite softer springs and weaker ARB
The total roll remains the same but you can decide if more is transfered across the front or rear of the car , increasing one end ,decreases the other -Front or rear
Increasing the rear roll resistance allows more roll "force /energy"(weight ) to be transfered across the rear and less across the front which will effect the amount of understeer
Yes is easier to understand and explain !!
Dec 7th, 2008, 06:38 PM
There are other factors such as is the car FWD or RWD ? and tyres and car height etc , but what works well on the track would not be what you need on the road , you could end up with springs so stiff that your teeth fall out on road surfaces:) and tracks are a lot smoother than roads -thats why an adjustable rear ARB is better as it allows you to alter to suit track or road and allows some adjustment for different spring stiffness
Dec 7th, 2008, 06:47 PM
Thanks so much for that. It does actually make perfect sense. Now I have the KW springs fitted it is lower & has a more agressive stance. They are also a good compromise between road & track....not that i've tested them on the track just yet but they will definately be better than stock as I can already feel that on every roundabout I take on.
I think the front wheel lift problem will have already been addressed slightly with the better outside rear resistance of the stiffer spring & lower stance but just need to address any chassis flex.
Like you say the rear ARB will counter a lot of this so i'll keep my eyes peeled. I notice that companies like GTT do a centre brace as well so I guess stiffening central chassis flex would also counteract this problem?
Dec 7th, 2008, 08:31 PM
Tony Foale Designs, article on car suspension geometry. (http://www.tonyfoale.com/Articles/carstuff/spring.htm)
Here is a very good article on what is happening when the car rolls