S2 111S understeer
Discussion
kelvyn said: After watching jemery Clarkson on top gear last nite driving the s2 111s then the geezer from lotus driving it, me dont thinks its the car understeering, me thinks its driver problem??????
Little more of the right foot needed
>> Edited by kelvyn on Monday 2nd December 19:42
>> Edited by kelvyn on Monday 2nd December 19:43
Hmm, anyone fancy braking while turning in on the road?
Has anyone got a set of the wide front tyres? I'd love to know what size they are.
As usual a bit of misunderstanding here
Yes on the track the clarkson comment was that he couldn't get the back end to break away. The lotus guy did liftoff and tip the car in to provoke a rear wheel break away - which he then recovered by accelerating through the corner
Clearly no-one is going to try this on the road.
The car is set up for safety - understeers first, to correct the understeer - should you wish to - the geo settings from arno above are spot on - or std geo with 185 tyres (possibly some experiementation may be necessary)
My point here is that few drivers can really approach the steering/grip limits of this car - and certainly will never do so on a public road
I notice stig had no problems with understeer ....
Yes on the track the clarkson comment was that he couldn't get the back end to break away. The lotus guy did liftoff and tip the car in to provoke a rear wheel break away - which he then recovered by accelerating through the corner
Clearly no-one is going to try this on the road.
The car is set up for safety - understeers first, to correct the understeer - should you wish to - the geo settings from arno above are spot on - or std geo with 185 tyres (possibly some experiementation may be necessary)
My point here is that few drivers can really approach the steering/grip limits of this car - and certainly will never do so on a public road
I notice stig had no problems with understeer ....
For anyone interested, Nick Adams of Lotus gave an explanation on the OLC BBS some time ago for the change in tyres sizes on the S2. The main points were as follows:
- The original Elise used an off the shelf tyre set and as a result did not have the ideal handling balance Lotus wished for. Essentially, the car had a bit too much front grip in the dry (making it more prone to lift off oversteer) and a bit too little front grip in the wet. The latter was essentially due to the front tyres being a bit too wide for the low front axle weight of the car (less than 1/3 of that of a typical FWD hatch for which the tyre was designed) resulting in the water getting under the tyre.
- The narrow front tyre on the S2 (and VX220) was chosen not to promote understeer as everyone seems to think, but to provide better front end grip in the wet. The narrower tyre increases the front contact patch pressure, thus cutting through the water better.
- All things being equal, the above would reduce dry weather grip too much so the compound of the tyre was softened to compensate for this. Lotus claim that this works and that ultimately in the dry a standard S2 will stay neutral longer than a standard S1.
- There is however a slight problem with the above approach, which explains why some S2 drivers experience excessive understeer. Softening the tyre to compensate for reduced width only works fully when the car has settled into a corner and achieved maximum weight transfer to the outside wheel. In practical terms this means the S2 requires a gentler approach to turning in so that the outside tyre can load in phase with the build up of lateral g. Drivers, on the other hand, who turn in abruptly will be more likely to get unwanted understeer as the lateral force will build up quicker than the car can roll and load up the outside tyre. Once the understeer has started its too late regardless of the tyre eventually getting the benefit of the weight transfer (as dynamic friction is less than static friction).
- So in a nutshell the S2 needs to be driven with smooth inputs to the helm to get the best out of it. If driven so, a standard S2 will stay neutral at marginally higher speeds than a standard S1 in the dry and at considerably higher speeds in the wet.
Hopefully my memory is good and that is an accurate summary of the official line from the Chief Engineer on the S2 project. As an automotive design/development engineer myself it all seems perfectly sound, although I will admit that ride and handling is not my particular field of expertise.
So next time that someone says that the S2 has skinny tyres to cater for hairdressers or some other section of society deemed to be unskilled drivers you will know that they are talking out of their ill-informed arses. In fact it seems that the exact opposite is true; the car requires a degree of finesse to perform to it's best as fully demonstrated by the time achieved (in the wet) by the Stig on Top Gear last Sunday.
>> Edited by Blackwheels on Tuesday 3rd December 19:20
- The original Elise used an off the shelf tyre set and as a result did not have the ideal handling balance Lotus wished for. Essentially, the car had a bit too much front grip in the dry (making it more prone to lift off oversteer) and a bit too little front grip in the wet. The latter was essentially due to the front tyres being a bit too wide for the low front axle weight of the car (less than 1/3 of that of a typical FWD hatch for which the tyre was designed) resulting in the water getting under the tyre.
- The narrow front tyre on the S2 (and VX220) was chosen not to promote understeer as everyone seems to think, but to provide better front end grip in the wet. The narrower tyre increases the front contact patch pressure, thus cutting through the water better.
- All things being equal, the above would reduce dry weather grip too much so the compound of the tyre was softened to compensate for this. Lotus claim that this works and that ultimately in the dry a standard S2 will stay neutral longer than a standard S1.
- There is however a slight problem with the above approach, which explains why some S2 drivers experience excessive understeer. Softening the tyre to compensate for reduced width only works fully when the car has settled into a corner and achieved maximum weight transfer to the outside wheel. In practical terms this means the S2 requires a gentler approach to turning in so that the outside tyre can load in phase with the build up of lateral g. Drivers, on the other hand, who turn in abruptly will be more likely to get unwanted understeer as the lateral force will build up quicker than the car can roll and load up the outside tyre. Once the understeer has started its too late regardless of the tyre eventually getting the benefit of the weight transfer (as dynamic friction is less than static friction).
- So in a nutshell the S2 needs to be driven with smooth inputs to the helm to get the best out of it. If driven so, a standard S2 will stay neutral at marginally higher speeds than a standard S1 in the dry and at considerably higher speeds in the wet.
Hopefully my memory is good and that is an accurate summary of the official line from the Chief Engineer on the S2 project. As an automotive design/development engineer myself it all seems perfectly sound, although I will admit that ride and handling is not my particular field of expertise.
So next time that someone says that the S2 has skinny tyres to cater for hairdressers or some other section of society deemed to be unskilled drivers you will know that they are talking out of their ill-informed arses. In fact it seems that the exact opposite is true; the car requires a degree of finesse to perform to it's best as fully demonstrated by the time achieved (in the wet) by the Stig on Top Gear last Sunday.
>> Edited by Blackwheels on Tuesday 3rd December 19:20
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