Nick Graves

According to the Certificate of Conformity:

Max weight 1535kg divided 703 front, 832 rear.

A lighter rear should give you more dry road grip for the same sized tyres, but it is likelier to be trickier in the wet or on a bumpy road.

A lighter rear should be easier to catch, as it carries less momentum.

Turtle

Unless you're past the limit of grip, the more weight on a tyre, the more grip it generates.

The max weight isn't relevant - it's the weight per tyre that is - if you want to know what your car is, have it corner weighed.

-Brian.

zero_to60

I'm with you Brian

I used to live in the US....drove an eighties Oldsmobile nice big V8 lump up front........no weight over the rear tyres equallyed a very tail happy car.....people think an S2000 is bad to drive in the snow....try an 'Olds'

Anyone who disagrees with Brian should remember F1 cars use 'weight' in the form of downforce to increase grip.....

The only time when weight is relevant is the pendulum effect.....but that's another story

MarkB

At Donnington the other week, my racecar was a bit tail happy going through Redgate corner, I didn't have time to do much, but one thing we did was to lower the rear spring platforms a bit.
This places more weight over the rear axle since the car is 'tilted' slightly backwards.
Result - more grip and less spins.

Think of tyre grip like pressing a rubber (eraser) onto a desk.
If you try and slide the rubber along the desk with only it's own weight resting on it, it's easy to push.
Now press down on the rubber and try to slide it, you need to push it harder to move it because it has more grip. Same with tyres.

More weight over the rear will increase momentum only when the limit of grip has been exceeded by the tyres.

Nick Graves

Exactly my point.

Turtle

But not really relevant in this case. You lost the back through too much power with too much lock on in 1st gear. Driver error. You did what every driver does unless they're used to it - paniced. (I've done this too.... as I'm sure anyone who's being honest has, short of the likes of Senna.).

I was trying to make this point a little more subtlety earlier in the thread.

Nothing to be gained by blaming the car in this instance - unless the car had a fault, like tyre pressures off etc. Though in that case, who's job is it to know about the fault?

Spinning, or losing the back end feels really quick when you're driving. But once you're used to the sensation, it's possible to notice the fraction of a second it takes. Once you're at that stage, you're past the panic and ready to take action in the fraction of a second. It's the panic - natural reaction - that's the problem.

The way I see it there are three choices for S2000 owners.
- get some training, so you know how the car behaves, and most importantly go through what it feels like so hopefully when something on the road puts the car out of control, driver panic won't make it worse.
- change the alignment (rear toe for one....) to build more self correction in if you want lifting off to work. Won't catch everything, and won't be pretty.
- buy another car, and go for all the electronics you can muster.

I favour the first option.

End of rant.

-Brian.

Nick Graves

Or an anger management course, eh Brian?

I thought I'd made it perfectly clear as to why I spun the car. As someone who has never had any problems with it in two years of hard driving in different conditions, I was merely sympathising with some that have experienced the sharp turn breakaway.

You weren't there, as far as I remember. I didn't panic. I was trying to relate that the rapidity of the breakaway, such that I couldn't have caught it. As I said, had I foreseen the road problem, I would have been better prepared/used less gun and it would not have happened.

Any car with a high g will (natually) break away rapidly once its limits are exceeded, I was merely suggesting characteristics that tend to exacerbate the effect.

I would also like to de-flame that I was not blaming the car. Others have got into long discussions about the effect of the LSD under such conditions (a normal diff allows the inner wheel to spin off excess torque) and I was confirming my agreement with this.

I would not recommend anyone to mess with the rear geometry. Breakaway characteristics are also a function of tyre design (as I was somewhat simplistically alluding to) and camber angle, as well as toe. Unless your name is Lotus, you will make it worse. In this case, It probably would have made little difference to a low speed/tight turn breakaway anyway.

Electonic aids are fine on a different car, although I suspect they may lead to less driving concentration, and therefore the greater likelihood of the laws of physics taking over.

Re-reading my post, perhaps it does come across with the wrong emphasis, but I am still delighted with the S2K.

Anyway, sorry to have upset you.

Turtle

Nope, how far you exceed the limit is the important bit - because you have to come back that far before the tyre will grip. Nothing to do with the weight of the car. You're right I wasn't there - I'm basing some of this on what you posted. Running out of RH lock - suggests you did have time to get the lock on, hence it wasn't 'snap'. Appears more like you weren't aware of how far past the limit the rear tyres were - driver error. Easily done - 1st gear, tight corner, sensitive throttle. Calling it 'snap' oversteer annoys when from what you've said it wasn't, and the setup of the car wasn't a major contributing factor.

Honda UK's recommended alternative alignement does exactly this. I have helped develop a different alignment for an S2000 running different suspension, with very good results. It's certainly not something to attempt blindly. Lotus's great skill is in damper valving (and spring rates), more than anything else.

It's not particularly aimed at you, but lots of people simply lurk and read posts. Internet forums can be good places for information, they can also spread loads of complete garbage. Whether I'm talking the garbage in this case or not I'll leave to the reader. But, having read your post I didn't want to leave it without comment - snap oversteer, weight distribution, lsd... etc. It's so easy for anyone to read posts and then think that's the whole story. I'm hoping to make the lurkers at least think a little - or better still get some training.

I wasn't intending to pick on you. Could have gone for Paul's post as well - pre-MY2002 cars can also understeer....

-Brian.

UK Paul

Ah but I was just being a tw@t .

Worst understeer I got was in packed snow at about 4 mph, I think I got full lock L & R twice before I booted it with pretty impressive results (and display ) felt Like Ayrton Senna, except only 160 mph slower.

However at Bedford only -steer I got was after advice from an instructor (do it in 3rd son, not 8500 in second so you can toe it down the straight), lovely snap oversteer when I lifted off in a wide corner because I knew I was going too fast in (although I think it would have scrubbed out speed in understeer if I kept it in, but this corner is the only one with Armco further round, so 'instinct' took over haha.

The tight chicane there is bloody marvellous in the S2000, a fully tooled up Subaru (All Prodrive bells whistles, flutes and more went by me on the straight into that corner, and as he understeered onto the grass I smartly turned in and went past him again.

Mans Best

[QUOTE]Originally posted by MarkB
[B]Think of tyre grip like pressing a rubber (eraser) onto a desk.
If you try and slide the rubber along the desk with only it's own weight resting on it, it's easy to push.
Now press down on the rubber and try to slide it, you need to push it harder to move it because it has more grip.