Ways to reduce lift-off oversteer

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OldNoccer	Ways to reduce lift-off oversteer		Lead	[-]
Registered Member Posts: 884 Sun, 29-Nov-2009 11:28	Tags : None I discovered lift-off oversteer a few months ago, when pressing hard on a sweeping left hand bend. I backed off suddenly (not advised) and the car instantly tried to shoot towards the left. It was very exciting for a moment as my brain caught up with my instinctive reaction. It was a sort of "Wow - what the hell just happened" moment. I have made a mental note to try not to snap-off the throttle when pushing hard, but I wonder if something in the setup could be adjusted. Just to make sure, I did it again on the same corner, this time prepared and with a bit more in-hand. I wasn't conscious that it was pushing the front before the event but it almost felt as if the front got more steerage rather than the back losing grip. I wondered if the blue front suspension polybushes are too soft, allowing the front suspension to deflect under load, but have since read that it is due to the rear end going light - but it didn't feel like a rear end break-away. Anyone else experienced this ? There's a lot of talk these days about green transport. Well, I am ahead of the game, I already have green transport ... British racing green.
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paulo		#1	[url]	[-]
Registered Member Posts: 128 Sun, 29-Nov-2009 12:02 Apprentice mechanic	I get the usual bump-steer which can be a little bit exciting at higher speeds but nothing like that. I've reduced the bump-steer I get by using wheel spacers at the front which, I guess, helps to correct the geometry of the chassis/wishbones etc. Makes the car look beter too.
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OldNoccer		#2	[url]	[-]
Registered Member Posts: 885 Sun, 29-Nov-2009 16:27	Bump steer has been done on mine - I suggest you contact Rory to get it fixed on yours : Bump steer fix There's a lot of talk these days about green transport. Well, I am ahead of the game, I already have green transport ... British racing green.
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Mike009 Gardner		#3	[url]	[-]
Registered Member Posts: 387 Mon, 30-Nov-2009 12:54 Junior mechanic	I think it is more to do with abruptly unsettling the balance of the car rather than anything to do with bushes etc. Smooth is order of the day with power on and off and braking too , that you way you can contol the balance of the car.
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zeke kaval	Ways to reduce lift-off oversteer	#4	[url]	[-]
Registered Member Posts: 2527 Mon, 30-Nov-2009 18:35 Major mechanic deity	Only time I got that was when I picked up a nail in the right front on the M40 but only found out about it when I was doing a 360 pirouette on the M4 sliproad, have you checked your tyre pressures lately?
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Jack		#5	[url]	[-]
Registered Member Posts: 1538 Mon, 30-Nov-2009 18:56 Guru mechanic	I had something similar years ago when I first bought the car... ended up going backwards towards the edge of a bridge right over a dual carriageway below! Rather scary but fortunately the only damage was to my pride! At the time I put this down to a lack of talent, but it turned out to be the rear suspension where all the bushes were very old & very knackered, the previous owner had recently replaced all the front bushes but not the rear ones, which unbalanced the car.... it was also probably a lack of talent too! Isn't the technique of smooth weight transfer called Trail Braking? http://www.drivingfast.net/techniques/track-corner.htm
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OldNoccer		#6	[url]	[-]
Registered Member Posts: 886 Mon, 30-Nov-2009 21:47	Thanks for the input - it shouldn't be the suspension bushes as the rear is all rose jointed IRS and I went over them and replaced as required a year ago, I replaced the front suspension arms and bushes at the same time. I am pretty sure it wasn't tyre pressures, though I admit to being a bit lazy and only checking them by eye 4 runs out of 5. I will check for bump-steer, even though it has been done, if I take the dampers off and compress the front to simulate weight transfer it should be apparent if extra turn is being added. I have had big engined cars for 30 years, but this is quite some way the lightest, so may weight transfer effects are more pronounced - though there is less weight to transfer ! However, if there is a way to reduce it, then I think it is worth tracking down. My first suspicion was that I had made it worse by refitting the front anti-roll bar. There's a lot of talk these days about green transport. Well, I am ahead of the game, I already have green transport ... British racing green.
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zeke kaval	Ways to reduce lift-off oversteer	#7	[url]	[-]
Registered Member Posts: 2528 Tue, 1-Dec-2009 00:53 Major mechanic deity	My Midas became tail happy if both the tyre pressures and fuel tank were low, so it had no weight to speak of in the rear and grip then became an issue if it was pushed, that said it was ok once I put wider tyres (without slow punctures) on it Last Edited By: zeke kaval Tue, 1-Dec-2009 00:57. Edited 1 time.
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dparslow		#8	[url]	[-]
Registered Member Posts: 725 Wed, 2-Dec-2009 16:41 Chief mechanic	Steve, you could just not ease off mid corner! It`s not more power you need, it`s less weight and a few subtle mods and some not so subtle!
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OldNoccer		#9	[url]	[-]
Registered Member Posts: 888 Wed, 2-Dec-2009 21:45	I had to ease off otherwise I would have hit an Elise up the jacksie ! I have added corner weghts to the list as I have yet to satisfy myself that I have them right. I found this link the other day with an idea for do it yourself DIY Corner Weights There's a lot of talk these days about green transport. Well, I am ahead of the game, I already have green transport ... British racing green.
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OldNoccer	Cause discovered !	#10	[url]	[-]
Registered Member Posts: 985 Sat, 8-May-2010 18:37	It took a while, but my car's problem is stiff front anti-roll bar and completely ineffective rear anti-roll bar (it has the IRS, and it loops forward of the diff). I have the car up on stands to do the CV joints, and have the dampers off. I realised I can lift one wheel hub up as far as I like without the other one moving. The anti-roll bar linkage looks OK, as do the bushes, but it is doing nothing! I think it is a standard Sierra type 12mm bar. So what's happening in a corner is probably the inside front wheel is going very light, maybe even in the air due to solid front ARB, and when I back off it hits the ground, gets grip, and I suddenly get 2 wheel steering, instead of a one wheel drift. Bingo, it whips the front towards the corner ! And that is what it felt like, it wasn't the back going out, it was the front suddenly turning in. This explains why it felt OK when I had the front anti-roll bar off. It wouldn't get out of a corner quick as the inside rear tyre got light, but at least both ends were nearly equally soggy, and as a result it didn't have any scary vices when you went on and off the power ! So thinking caps are on for a new rear ARB setup. Steve My car is not scary at all, in fact it's quite docile .. until I start the engine.
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Ways to reduce lift-off oversteer

Ways to reduce lift-off oversteer