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Dec 19, 2010 19:26:01 GMT
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Increasing front grip can only be done by softening the front end. Can be detrimental to suspension geometry, especially on little french hatches which have very little camber gain anyway, and zero on the rear. The only good handing FWD cars I've seen that don't cock a rear wheel are the ones on the hills that run something along the lines of 9" slicks on the front and 7" slicks on the back and really good roll control. Even Ralph Pinders little rocket ship picks up the inside wheel every now and again: www.zipp.co.uk/gallery/Prescott-2010-04-25/34+0303.jpg.htmlMore camber and castor would do that. The castor especially would help with the wheel lifting. Extra castor isn't easy to achieve without specialist kits, though, and isn't usually desireable in hill climbing specifically. Static camber is also undesirable as its detrimental to grip off the line. Static castor isn't good fun as it makes turning into tight corners a bit of a biatch. Its all a bit of a 'what works for you' at the end of the day. The issue is that the limiting factor of grip in a car with loads of weight infront of the front axle line (ie small FWD hatches) is the grip of the front wheels. You can get rid of loads of grip from the rear end without reducing the overall grip of the car, and it just so happens that reducing the weight on the inside rear increases the weight on the inside front, also increasing the grip at the front end. You aren't really reducing the grip at the rear end as, unless you're driving very stupidly, you will never be reaching the limit of grip at the rear. You are however increasing the limit of grip at the front, which you will be reaching quite regularly. Hence understeer is reduced and time go down! I suppose what i'm saying in a long winded way is that you aren't just reducing rear grip, you're increasing front grip on the wheel that is reaching the limit of grip (ie outside front).
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1997 TVR Chimaera 2009 Westfield Megabusa
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Dec 19, 2010 19:55:18 GMT
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Thanks for all the help and advice it will be put to good use
the car in question is a mk1 clio with a vts lump will be built purely for tarmac based motorsport
full build thread after christmas
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Dec 19, 2010 19:55:41 GMT
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my mates maestro used to do it on one particular corner when taken at....speed
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1984 Subaru GLF Hatch 1983 Skoda 120LE Super estelle 1977 Subaru DL Wagon 1978 Datsun 120Y Coupe 1995 Skoda favorit estate
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CIH
Posted a lot
Posts: 1,466
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Dec 19, 2010 20:39:36 GMT
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More camber and castor would do that. The castor especially would help with the wheel lifting. Extra castor isn't easy to achieve without specialist kits, though, and isn't usually desireable in hill climbing specifically. Static camber is also undesirable as its detrimental to grip off the line. Static castor isn't good fun as it makes turning into tight corners a bit of a biatch. Its all a bit of a 'what works for you' at the end of the day. The issue is that the limiting factor of grip in a car with loads of weight infront of the front axle line (ie small FWD hatches) is the grip of the front wheels. You can get rid of loads of grip from the rear end without reducing the overall grip of the car, and it just so happens that reducing the weight on the inside rear increases the weight on the inside front, also increasing the grip at the front end. You aren't really reducing the grip at the rear end as, unless you're driving very stupidly, you will never be reaching the limit of grip at the rear. You are however increasing the limit of grip at the front, which you will be reaching quite regularly. Hence understeer is reduced and time go down! I suppose what i'm saying in a long winded way is that you aren't just reducing rear grip, you're increasing front grip on the wheel that is reaching the limit of grip (ie outside front). I don't understand how lifting a rear whel isn't reducing rear grip ? I agree too much camber impacts upon traction but IMO you would need a lot to really be an issue, say ~3.0 negative.
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Last Edit: Dec 19, 2010 20:40:03 GMT by CIH
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Dec 19, 2010 23:14:17 GMT
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You are reducing the amount of rear grip available, you aren't reducing the amount of it you use. Is that worded slightly better? I know what i'm thinking in my head but I'm curse word at writing it down!
About -3deg static camber is what you need on 205s/106s to make the most of the tyres if running relatively soft front end! Unless you reposition the top of the wishbone, which is illegal in most production classes.
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Last Edit: Dec 19, 2010 23:18:55 GMT by Adam
1997 TVR Chimaera 2009 Westfield Megabusa
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Dec 19, 2010 23:26:41 GMT
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Either you're going to have it stiff all round to maintain good camber control and keep heat in the tyres, or you're going to run compliant all round to allow the wheel to follow the road as well as possible.
Either way, the inertia created by the engine being out the front (which is not affected by suspension stiffness or geometry) will require more grip at the front than the rear, so you will always end up gaining maximum grip with a nice stiff rear which encourages weight transfer to the outside front. This will almost always end with the inside rear in the air (as long as the centre of gravity is high enough...) as the one tyre at the rear provides more than enough grip to keep the rear on the straight and narrow.
Even if the wheel isnt noticable off the ground, it will usually be almost completely unloaded.
There is no way around it!
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Last Edit: Dec 19, 2010 23:35:08 GMT by Adam
1997 TVR Chimaera 2009 Westfield Megabusa
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