Antnicuk
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| posted on 24/4/10 at 09:24 PM |
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Any Idea's How to Stop InsideFront Wheel Lifting ?
When ever i see photos of my car on track days its lifting the inside front wheel. Is there a cure for this? Any suggestions welcome?
600 BHP per ton, Stylus Brought back from the dead! Turbo Rotary Powered!
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mangogrooveworkshop
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| posted on 24/4/10 at 09:29 PM |
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I cant see what the problem is that looks fab
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mookaloid
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| posted on 24/4/10 at 09:30 PM |
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it seems to be rolling and squatting. I would try increasing the spring rates at the rear particularly and consider fitting anti roll bars or uprating
if you already have some.
"That thing you're thinking - it wont be that."
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phelpsa
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| posted on 24/4/10 at 09:32 PM |
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quote:
Originally posted by Antnicuk
When ever i see photos of my car on track days its lifting the inside front wheel. Is there a cure for this? Any suggestions welcome?
Do you find the car excessively understeery?
Stiffer rear springs would reduce it but also increase oversteer tendancy.
My 205 likes to kick up inside rear at every opportunity 
[Edited on 24-4-10 by phelpsa]
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Antnicuk
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| posted on 24/4/10 at 09:34 PM |
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i have just gone up from 250lb to 275 on the rear, the fronts are 300lbs, i have a massive antiroll bar on the front set on the firmest settiing.
Is it wrong to have the same spring poundage on the rear as on the front?
It doesnt feel very understeery but if ever does slide at the front on tighter bends, a quick blip of the throttle soon brings the back round
I prefer oversteer, i can deal with that but i hate undertseer
The pic was taken today.
[Edited on 24-4-10 by Antnicuk]
600 BHP per ton, Stylus Brought back from the dead! Turbo Rotary Powered!
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Humbug
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| posted on 24/4/10 at 09:34 PM |
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Take corners slower? 
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Xtreme Kermit
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| posted on 24/4/10 at 09:43 PM |
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I thought fronts were usually a lower rate than the rear.
Doesn't front sliding wide = understeer?
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zilspeed
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| posted on 24/4/10 at 09:43 PM |
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I'm not sure it's a terrible thing, unless it's picking up under slow corners under braking, where it is a bad thing.
Personally, I wouldn't want to stiffen up the rear end too much, because with all of that turbo grunt, the last thing you need is less
traction.
You already have an adjustable front roll bar.
Why not fit a rear one and bring the back one into play gradually whilst easing the front one off gradually. Try and find a balance that way without
increasing spring stifness
How does the car actually feel whilst it's cocking a wheel like this ?
P.S. It never harmed the great Jim Clark. Once he knew the Lotus Cortina did this, he used it to his advantage and got tighter into the corner.
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phelpsa
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| posted on 24/4/10 at 09:45 PM |
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quote:
Originally posted by Antnicuk
i have a massive antiroll bar on the front set on the firmest settiing.
There you go then. That's what's causing it! Reduce the stiffness and you'll get a more compliant front end and more front end grip.
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mookaloid
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| posted on 24/4/10 at 09:45 PM |
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I don't actually think it's a very serious problem. I've seen plenty of cars do this - and I'm sure I've seen pics of F1
cars doing it.
the inside front wheel doesn't do a lot on exit from a corner as all the weight is on the outer wheel anyway. A more serious problem is if the
inside rear wheel spins up thus losing drive out of corners. if this happens a lot it's time to get a LSD.
"That thing you're thinking - it wont be that."
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phelpsa
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| posted on 24/4/10 at 09:48 PM |
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As mook says, its not a bad thing unless you're missing front end grip.
Any weight that isnt on the inside front is on the outside rear, which is where you want it on the exit of a corner for more rear end traction
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Antnicuk
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| posted on 24/4/10 at 09:55 PM |
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i will try and ease of the arb ( meant to do it today at the track but i was having too much fun)
It doesnt do it on bigger bends, only smaller ones. Although i am very agressive which im sure doesnt help
I have a silva style rear so i have opposing trailing arms meaning that the live axle acts as an arb from what i understand.
I found that bend n the photo, which always seems to have the most lift, particularly hard to get right. Its hard to tell whats going due to my
inexperience and the car is a bit manic! great fun though!
The rear is so controllable and i can make the front or rear slide depending on what i do, it makes the car really easy to control beond the limit
and it will get very sideways and as long as im quick, i can keep it going in the direction i want.
It would be nice to feel a bit more planted in the corners though instead of having to fight it round the track. In the technical tight bits i found
stabbing the brakes as i went into a tighter corner improved front end tration and not getting on the gas too early helped eliminate any understeer in
the tight bends.
Not sure if this is right 
[Edited on 24-4-10 by Antnicuk]
600 BHP per ton, Stylus Brought back from the dead! Turbo Rotary Powered!
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phelpsa
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| posted on 24/4/10 at 09:57 PM |
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Sounds like backing off the ARB will definitely help!
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Steve Hignett
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| posted on 24/4/10 at 10:02 PM |
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quote:
Originally posted by Antnicuk
I have a silva style rear so i have opposing trailing arms meaning that the live axle acts as an arb from what i understand.
How is the rear attached? (rubber or poly bushes, if rubber, what type etc)
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adithorp
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| posted on 24/4/10 at 10:04 PM |
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Soften the front ARB and stiffen the rear. As the outside front suspension is compressed the front ARB is trying to prevent the inside suspension
extending and it lifts.
But if the balance is good and it's not understeering...
adrian
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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mookaloid
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| posted on 24/4/10 at 10:04 PM |
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with a live axle it is much simpler - the rear roll is entirely a function of the spring rates.
If you over do it on the spring rates then it will get very skittish at the rear so maybe try another step up at the rear to see how you like it but
be prepared to go back to the current ones if you don't like it.
as you are finding out - car set up is a compromise. if you get it working well on that slow corner then it might not be as good on the faster corners
as it is currently. So have a mess about with spring rates and see how you get on
"That thing you're thinking - it wont be that."
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Antnicuk
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| posted on 24/4/10 at 10:09 PM |
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thanks guys, i will have a play with the arb.
Dont shout at me but i rose joint the rear arms at the chassis ends and the axle ends are poly bushed, people have said its wrong but it works well
for me i think
600 BHP per ton, Stylus Brought back from the dead! Turbo Rotary Powered!
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JoelP
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| posted on 24/4/10 at 10:28 PM |
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quote:
Originally posted by Antnicuk
It doesnt feel very understeery but if ever does slide at the front on tighter bends, a quick blip of the throttle soon brings the back round
That sounds like it does understeer when pressed. With only one wheel on the ground you will get less grip turning in. The 205s etc lift a rear wheel
cos (i think) its a torsion bar at the back which cannot bend much, ie its like it has a tough antiroll bar. You have the same at the front. As the
body rolls the wheel gets lifted by the ARB.
TBH, myself id take it off entirely and see how different it is, you will get a much more noticable difference than if you just adjust it slightly.
Then you can see if you prefer it with or without.
Or, splash out, take it to someone who knows kit handling well, and let them fiddle.
Beware! Bourettes is binfectious.
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phelpsa
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| posted on 24/4/10 at 10:57 PM |
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quote:
Originally posted by JoelP
quote:
Originally posted by Antnicuk
It doesnt feel very understeery but if ever does slide at the front on tighter bends, a quick blip of the throttle soon brings the back round
That sounds like it does understeer when pressed. With only one wheel on the ground you will get less grip turning in. The 205s etc lift a rear wheel
cos (i think) its a torsion bar at the back which cannot bend much, ie its like it has a tough antiroll bar. You have the same at the front. As the
body rolls the wheel gets lifted by the ARB.
TBH, myself id take it off entirely and see how different it is, you will get a much more noticable difference than if you just adjust it slightly.
Then you can see if you prefer it with or without.
Or, splash out, take it to someone who knows kit handling well, and let them fiddle.
205 rear end is a completely independent trailing arm set-up with torsion bars, very different to the torsion beam as found on Golfs etc I have
fitted a 24mm rear ARB though.
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brianthemagical
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| posted on 25/4/10 at 08:56 AM |
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The issue with 205's, as with many hatch's and to a certain extend the OP's car, is roll axis inclination. The front and rear roll
centres are at different heights-on the floor on the back of a 205, and about 4"-6" on the front depending on lowering, on most live axles
it's at the axle centre height, so maybe 8"-10" depending on wheels.
This then causes the front and rear to roll at different rates, skewing the body, not just lifting the wheel.
As above, softening the front ARB may help, failing that try and lift the front roll centre, even if everything else on the car is wrong, and see how
it rolls.
[Edited on 25/4/10 by brianthemagical]
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britishtrident
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| posted on 25/4/10 at 09:48 AM |
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It dosen't look too bad but the front arb is too stiff, once you stiffen the front roll stiffness beyond a certain point you get 100% weight
transfer and increasing the front roll stiffness further has no effect.
Reduce the front anti roll bar stiffness and stiffen the rear springs relative to the front both of which will reduce understeer and may push you
into an oversteer situation --- an oversteering feels fast but isn't so test against the stop watch.
Order order doing things
(1) Reduce anti roll bar stiffness --- and test
(2) Swap front and rear springs --- and test
If that gives you too much oversteer try fitting a set of 300lb/in springs to the front rather than stiffen the arb.
[Edited on 25/4/10 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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mangogrooveworkshop
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| posted on 25/4/10 at 11:01 AM |
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Ive got some 300 lbs springs you can have for a token beer
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MikeRJ
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| posted on 25/4/10 at 11:22 AM |
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quote:
Originally posted by mookaloid
with a live axle it is much simpler - the rear roll is entirely a function of the spring rates.
Not on the live axle Striker/Fury etc. They have built in roll stiffness due to using a watts linkage for longitudinal location of the axle at each
side instead of the standard 4 link setup. In roll the linkages try to twist the axle and the deflection of the rubber bushes in the linkages
determines roll stiffness (+ springs obviously).
The OP's picture remind me very much of Mk1/Mk2 Escorts that I see on local tarmac rallies; for some reason they always seem to have far too
much roll stiffness at the front and end up with the inside front wheel way up in the air.
[Edited on 25/4/10 by MikeRJ]
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mookaloid
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| posted on 25/4/10 at 11:36 AM |
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quote:
Originally posted by MikeRJ
quote:
Originally posted by mookaloid
with a live axle it is much simpler - the rear roll is entirely a function of the spring rates.
quote:
on the live axle Striker/Fury etc. They have built in roll stiffness due to using a watts linkage for longitudinal location of the axle at
each side instead of the standard 4 link setup. In roll the linkages try to twist the axle and the deflection of the rubber bushes in the linkages
determines roll stiffness (+ springs obviously).
I didn't realise that the striker uses a watts linkage. So thinking about it - it would be a bad idea to make a watts linkage using rose joints
then?
quote:
OP's picture remind me very much of Mk1/Mk2 Escorts that I see on local tarmac rallies; for some reason they always seem to have far too
much roll stiffness at the front and end up with the inside front wheel way up in the air.
I have seen many escorts doing this too - they seem to get round the corners ok
"That thing you're thinking - it wont be that."
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sebastiaan
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| posted on 25/4/10 at 11:45 AM |
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quote:
Originally posted by MikeRJ
The OP's picture remind me very much of Mk1/Mk2 Escorts that I see on local tarmac rallies; for some reason they always seem to have far too
much roll stiffness at the front and end up with the inside front wheel way up in the air.
[Edited on 25/4/10 by MikeRJ]
Traction, traction and traction ;-) Keeping the rear wheels on the tarmac helps acceleration out of corners. By having the front roll stiffness higher
than the rear, most of the weight transfer happens at the front, thus lowering weight transfer at the rear. This in turn aids traction.
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