Gaining full contact patch on extreme lock

I fully understand the caster and contact patch part of this module turning from 20 degrees and such. It is my understanding that on normal circuit Racing it is very unlikely for the driver to turn more then this amount. However in drifting the car spend most of its time well beyond the 20 degree mark is there a way of maximising the contact patch at these extreme angles. Ensuring that front end grip isn’t lost by being in full oversteer. This problem has normally been solved by running extreme camber on the front of the car to ensure you have the grip but what is the correct way to measure this and where.

any help would be great thanks

From my understanding it's the range of angle that you are measuring, whether it be 10, 15 or 20 degree, the calculation should still achieve the same value.

I may be wrong but the calculation for 20 degree is the difference in the two camber angles in and out multiplied by 1.5

15 degree is x2.0 and 10 degree is x3.0

This is a post i saw on another forum

Caster is an inferred angle, not measured directly. It is inferred from the difference in measured camber (measured directly) with wheels turned 20 degrees in, then 20 degrees out.

Measure camber X degrees in & X degrees out.

If both camber readings are negative or both readings are positive, subtract the absolute value of the two readings and multiply by the constant for the angular in/out value you are using, below.

If one reading is negative and the other is positive, add the absolute value of both and multiply be the appropriate constant, below.

Angular value constants

20 degrees = 1.5

15 degrees = 2.0

10 degrees = 3.0

Hey Stu, so it is my understanding that when it comes to Caster for drifting, the max settings are usually a good starting point, this will help the steering wheel counter steer more quickly. The reason we measure to 20degs is simply to get our caster reading and thats how our bubble gauge is set.

For Camber settings, you should be able to do a camber reading with the wheels at full lock. This should give you a reasonable idea of how much tire is in contact with the ground (0degs camber will be the most tire contact). However, you need to consider that when the car is on track, that the chassis is always moving and therefor the amount of tire pressing down will be constantly changing, so your camber readings won't be completely accurate. The aggressive camber settings you see on drift cars is simply to compensate for the extreme amount of lock the drivers put in.

Hope this helped

Matt

Hey matt and James, thank you very much for your feed back on my issue. i will be attempting my first alignment of my Car this weekend so your advise was really helpful. I have normal used a standard run set up on my old Cars which have only had adjustable top mounts on them.

this will be my first time attempting to set the new car up using this kind of method now i have full adjustable arms, tie rods camber and caster both front and rear. i am very interested to the results. i will post up my set up if successful.

many thanks

Stu

Great to hear!!

Let us know how it goes

RaceCraft Team

Not something I'm that interested in, so might be quite wrong.

I suspect a big part of it is the use of large caster angles to help the self-centring of the vehicle from lock, especially when the wheel is released. I think it is required because these vehicles use a LOT of wheel offset which means a large scrub radius and more drag on the steering against the self centring which has to be countered.

To get a reasonable tyre contact patch quite a lot of negative camber is used to counter the camber gain from the caster and body roll.

That may also be part of the reason they use such STUPID amounts of stretch - heck, 'stretch' is stupid, period! - the trapezoid section it forms may also tend to have some affect on the tyre contact patch as it is loaded laterally, although it is really more useful with crossply tyres.

I repeat, though, not something I've much interest in - perhaps if you were to be-friend some of your local 'drift' chaps and talk to them?

Gordon,

I'm trying to use the caster as much as I can to avoid the need to run such an aggressive camber on the front. This is finding the balance between losing the self Centre effect and gaining as much grip on full lock. I’m pushing my luck trying for the best of both worlds having more grip in a straight line and grip on lock.

the stretch tyres thing is a controversial conversation in the sport I personally Don’t like the idea for running huge stretch but it’s finding a balance once again. I run a 10mm stretch on my current set up (front only) but only to avoid arch on full bump travel.

I find talking to a lot of people at my level it’s seems to be more of looking the part then it being effective Which is why I’ve turned to this form.