29 replies to this topic

[Nev]

You guys had me doubting myself lol, had to check my print outs... Yes i have toe OUT at the rear. Because its mainly a track car and hardly used on the road. It does make it sketchy on a wet road. Keep in mind that I mainly drive Knockhill and this has been proven to work on other lotus based chassis here. In the dry its fcuking awesome. Anyways to answer the OPs question, adding some camber like you said and keeping the front and rear toe fairly standard it should be fine on the road. You can always change it back again with relative ease on these cars so just give it a try and see if it for you or not.

 

I think you ought to try toe in on the rear mate and toe out on the front - I think you'll get a more positive turn in as a result. Toe out on the front is particularly beneficial if you have lowered the front end, as it helps partly compensate/neutralise the steep bump steer curve when the front wheel hits a bump (ie under compression).

Edited by Nev, 24 June 2016 - 07:22 PM.

[NOSBandit]

I agree with Nev. I have slightly less negative camber, but mine is rose jointed so no change in geo when cornering.

Of cause there is a change.. Rose jointed just means the connections wont have any play, it doesnt mean the geo wont dynamically change..

Geometry is a lot more precise using rose joints then bushes, of course there will be some flex in chassis, wishbones and tyres

[chris_uk]

when you brake your geo changes... when you accelerate it changes, when you lean on it in the corners it changes.. 

 

so your geo changes dynamically to what you are doing..and im not talking about chassis flex,

 

if your car didnt change the geo when driving you would basically be driving a shopping trolly. 

 

[NOSBandit]

Obviously the geo changes whilst driving, but rose joints take out the unexpected movement that you get with rubber bushes making it more precise.

[chris_uk]

You guys had me doubting myself lol, had to check my print outs... Yes i have toe OUT at the rear. Because its mainly a track car and hardly used on the road. It does make it sketchy on a wet road. Keep in mind that I mainly drive Knockhill and this has been proven to work on other lotus based chassis here. In the dry its fcuking awesome. Anyways to answer the OPs question, adding some camber like you said and keeping the front and rear toe fairly standard it should be fine on the road. You can always change it back again with relative ease on these cars so just give it a try and see if it for you or not.

  I think you ought to try toe in on the rear mate and toe out on the front - I think you'll get a more positive turn in as a result. Toe out on the front is particularly beneficial if you have lowered the front end, as it helps partly compensate/neutralise the steep bump steer curve when the front wheel hits a bump (ie under compression).

Depends if he wants on power turn in, off power turn in, mid corner turn in.. The characteristic of toe out on the front usually gives great initial turn in but understeers mid corner as people tend tobelieve then can turn in at higher speeds and think they can carry the speed when in fact they cant, having toe in would take away the sharp turn in and just give a blander turn in but you would be less likely to wash out.. Having the toe out on the rear will mean the car will want to rotate through any corner whoch one could argue helps turn in. The reason it works well in the dry is due to the tyres keeping him in check, so his car might handle well in 1 scenario of good weather but when the weather turns it will handle like sh*t as he admits.. This is usually down to a car being really shitty balanced.. A well balanced car will be exactly that with what ever tyres you put on it, it will communicate with the driver at all times.. take away the balance and you basically have a shitty car which seems to handle well because the tyres are masking the cars handling faults.

[chris_uk]

Obviously the geo changes whilst driving, but rose joints take out the unexpected movement that you get with rubber bushes making it more precise.

Well, thats not what you originally said.

[NOSBandit]

Obviously the geo changes whilst driving, but rose joints take out the unexpected movement that you get with rubber bushes making it more precise.

Well, thats not what you originally said.

It might have been badly worded but I meant that I can run a slightly less negative camber, as I don't have any rubber bushes to crush under load that will effect the camber in cornering.

[Nev]

 

 

Obviously the geo changes whilst driving, but rose joints take out the unexpected movement that you get with rubber bushes making it more precise.

Well, thats not what you originally said.

 

It might have been badly worded but I meant that I can run a slightly less negative camber, as I don't have any rubber bushes to crush under load that will effect the camber in cornering.

 

 

 

Yes it was badly worded, precise words for a precise subject are required.

 

 

I recently did some bench tests of a new and old bush by sticking a bar into one on a vice, just to gain a vague feeling of their elasticity. When levering the bar up and down, it's surprising how hard it is to deform them. I can't imagine they even deform more than 1 mm under heavy load like this during bump or droop. However, what I did notice is that under braking/acceleration they are prone to move forward/backwards perhaps 2 or even 3 mm if the washers/spacers are not flush/tight next to them in the chassis leg.

 

 

 

 

Edited by Nev, 25 June 2016 - 06:33 AM.

[Nev]

 

The characteristic of toe out on the front usually gives great initial turn in but understeers mid corner as people tend tobelieve then can turn in at higher speeds and think they can carry the speed when in fact they cant, having toe in would take away the sharp turn in and just give a blander turn in but you would be less likely to wash out..
 

 

In regards to the front end, I think you are right Chris for OEM ride heights.

 

A point I was trying to make, is that when owners inevitably lower their front ends that many don't realise that they are causing the front end wishbones to be articulating on a steeper part of the bump steer curve (ie when the front end hits a bump the change of toe in increases faster than Lotus designed). This is because the bump steer toe in under compression is a logarithmic function, ie not much toe in for a little bump, but loads and loads of toe in for a big bump. For this reason if you have lowered the front end, if you initially had toe out on the front, when the car hits a bump the extra toe (from lowering) in is slightly alleviated by the initial toe out.

 

It's subtle stuff and I expect 95% of owners don't think about such things, I know I didn't when I first bought Nipper. It's knowledge of stuff like this that the better Geo shops/professionals will take advantage of and give owners a better drive.

 

 

Edited by Nev, 25 June 2016 - 06:35 AM.

[Aerodynamic]

From my learning -2.7 deg camber is about max for road using track car without destroying the tires, tested on both current and last car. If only used on track you can go more.