View Full Version : am i right in thinking


dannytwo
21 July 2004, 18:40
that when you brake going in to a corner it aids you grip,throwing the weight to the front wheels?

i know this does'ent always apply.

dannytwo:)

fitzscoob
21 July 2004, 20:16
I was under the impression that you needed to keep the speed constant for optimum grip, generally you lose traction on corners if you accelerate hard or decelerate hard. Keep the power even.

I may be wrong on 4wd but when I was hammering some poor sods set of supercars around a race track thats what I was instructed :P

ScoobySport (SdB)
21 July 2004, 21:00
There are two main things to consider.

1) the end with the most load on it, is the most likely to grip best.
2) if you demand longitudinal traction (accelerating / braking) from a tyre, you reduce it's ability to corner.

So.. whilst braking and / or accelerating in a corner should theoreticall reduce the overall grip of the car, the handling will be affected by braking or accelerating.

In moderation, accelerating will create understeer, and braking will create oversteer.

All the best

Simon

Red Man
21 July 2004, 22:10
There are two main things to consider.

1) the end with the most load on it, is the most likely to grip best.
2) if you demand longitudinal traction (accelerating / braking) from a tyre, you reduce it's ability to corner.

So.. whilst braking and / or accelerating in a corner should theoreticall reduce the overall grip of the car, the handling will be affected by braking or accelerating.

In moderation, accelerating will create understeer, and braking will create oversteer.

All the best

Simon
Thankyou my friend - whilst these points might seem obvious they have raised a certain fog of confusion I have about the scooby handling - see previous thread. So if I read this right braking hard into a corner throws more grip onto the front wheels, which could if the grip levels were loose cause the back to slightly break traction whilst the front wheels hold firm. This is what I seem to have been experiencing, but seemed to confound the Scoobynet common view that the car naturally understeers.

If I have got this right - then many thanks

Steve Whitehorn
21 July 2004, 23:04
Yes and No :)
It depends on how you drive it and many many other factors inc tyres, diff control etc
Lets say it is down to how you drive it

People say that scoobs do understeer and they are right if driven correctly, however they are prone to lift off oversteer.

Many people will acellerate, load up the rears. Get to the end of the straight brake, load up the fronts. Get the car balanced, equal load on front and rears, before they comit to the bend. Correct entry speed and a nicely balanced car is everything. Because a scoob has so much grip you can feed the power on progressively before the apex. When you do reach the limit of the tyres grip, usually towards the end of the bend because you are asking too much of the fronts in terms of cornering and acelerative grip the fronts will be the first to let go. Hence why people say scoobs understeer.


However if you are braking later, actually into the begining of the bend then the fronts will be loaded up with less load on the rears. Therefore you will be inducing a certain amount of induced oversteer. (trail braking if you like)

This is a higher risk strategy for fast road use. The first technique is safer as the car is more stable going into the bend and also this technique can give you very quick exit speeds from bends. which along with good brakes is what will really give you the advantage

Hope this helps
Steve

Red Man
22 July 2004, 07:25
Again great feedback guys - thanks a lot.
Am I right in understanding therefore that the typical scooby understeer occurs under power as you transition out of the corner - this I think I have experienced (or at least I can feel the steering getting light - if that makes sense?)

The few occasions where I brake very late deliberately are reserved for a farm track with good run off and sighting with sharp loose bends so the speed is relatively low. Here the front grips and the back goes light - I presume this is a degree of trail breaking. I am doing this to get a feel, safely, for how the car behaves - and I must say it seems pretty controllable - nothing gets away too quickly (but this is on rough road and gravel). I would be loathe, however, to take this approach on fast tarmac public roads - and your advice suggests I am right to be cautious about this:rolleyes:

Once again thanks for taking the time to help me get to grips with all of this:)

Claudius
02 August 2004, 11:48
So if I read this right braking hard into a corner throws more grip onto the front wheels, which could if the grip levels were loose cause the back to slightly break traction whilst the front wheels hold firm. This is what I seem to have been experiencing, but seemed to confound the Scoobynet common view that the car naturally understeers.
You're right.

The car understeers if you dont brake hard enough into the corner or if you are not driving fast and then accelerate out of the corner too early (because of the weight in the rear, the lack of grip in the front, the standard geometry, the lack of a LSDs and because you accelerated too early).

knap
03 August 2004, 23:28
Interesting article explaning load and grip
http://www.dsm.org/archives/1997/07/19970724.txt/32.html
and the traction budget
http://www.miata.net/sport/Physics/07-Circle.html

The Mini Daddy
07 September 2004, 19:00
hmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm

it does up to a certain point when the grip levels are exeeded by driving force.

at this point you go straight on into some unwanted object which always comes off better than your own motor.


A reg datsun sunny vs over steering zonda

game set and drawn , lol

l8erz

The Mini Daddy
07 September 2004, 19:04
also


lets say a tyre when stood still has a range of 100% grip to be shared by all the forces exerted on the wheel

if there is 60 driving force and 40 cornering force the car will be twitchy but controlable

if there is 75 driving force going through the rear wheels and 50 cornering force the grip "percentage" is exeeded and the tyre looses all grip. eg oversteer;)


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