ex-webby

Hi All

To kick things off, I thought I'd offer this quiz. Post your answers in the format indicated at the bottom of this post. The answers will be posted up within the next few days.

(Disclaimer : All quesitons and answers are based on the "by far the most likely", rather than a hard and fast rule that will apply in every single situation).

There are some pretty easy ones, and some more difficult ones, so there should be something in there for everyone.

Good luck!

Question 1
You are competing in a circuit race and you car is fitted with a brake bias control. The heavens open and the circuit is wet within seconds and you're on a dry set-up. The only thing you are able to change is the brake bias, shoudl you.

a) Wind on more rear brakes
b) Wind on more front brakes

Question 2
Stiffening your front anti-roll bar will usually make the car tend more towards :

a) Understeer
b) Oversteer

Question 3
Bump steer is :

a) The steering force created in the tyres when you hit a bump
b) The change in toe angle during bump and rebound travel of the suspension
c) Camber changes during the bump and rebound travel of the suspension

Question 4
You are cornering in an standard AWD Impreza on the limit and all tyres are at the point of slipping. What course of action would most likely cause sudden oversteer.

a) Full throttle
b) Add more positive steering lock
c) Zero throttle

Question 5
Securely fixing something heavy into the boot of your car, is more likely to create

a) Understeer
b) Oversteer

Question 6
The Subaru Impreza suspension arrangement is known as :

a) MacPherson strut
b) Wishbone
c) Leaf Spring

Question 7
Taking two cars of the same power to weight ratio, one weighing more than the other (so also having more power to compensate) which will have the highest top speed.

a) Heavier, more powerful car
b) Lighter, less powerful car
c) Both exactly the same

Question 8
Taking the same two cars, which would be the fastest round a constant circle (like a roundabout).

a) Heavier, more powerful car
b) Lighter, less powerful car
c) Both exactly the same

Question 9
Which will stop the quickest from 100MPH

a) Heavier, more powerful car
b) Lighter, less powerful car
c) Both exactly the same

Question 10
What is the most likely effect on a car if you increase the rebound resistence of the front dampers

a) More front end grip under acceleration
b) More front end grip under braking
c) More rear end grip under acceleration
d) More rear end grip under braking

Question 11
During theoretical steady state cornering (not acceleraing, decelerating, etc) which of the following is most likely to caused more oversteer

a) More rear rebound resistence
b) More front rebound resistence
c) More rear bump resistence
d) More front bump resistence
e) More front negative camber
f) More rear negative camber

Post your answers as follows :

[question no] : [answer]

eg.
1 : D
2 : E
3 : C
etc.

All the best, and good luck

Simon

johnfelstead

1:A

2:A

3:B

4:C

5:A

6:A

7:A

8:B

9:B

10:A

11:E



10 i am pondering most because it depends what transition state you are coming out of. It also depends whether you mean grip or traction, because in an AWD car you gain more traction making the front more usable, but in a RWD car you would gain more rear end grip. So for AWD i'll go with A, for RWD i'll go with C. Some good questions.

ex-webby

well done John for answering.. Come the rest of you whimps! get stuck in!

ex-webby

PS. remember, it's just a bit of fun, and we'll all learn something.

Even John has got some wrong (can't wait for our "discussion" john!! LOL - drop me a mail if you want to discuss in the mean time) although admitedly only REALLY tricky ones.

If there's a good response, it will spur us on to do more, and create articles, etc.

PS. Damian Harty is not allowed to take part!!! LOL

Hammy Hamster

1: A

2: A

3: B

4: C

5: A

6: A

7: A

8: B

9: B

10: D

11: E

Shaun

1:A
2:B
3:B
4:C
5:A
6:A
7:C
8:B
9:B
10:A
11 Doh... that does a smiley should be 11=D

johnfelstead

some, as in more than one. LOL

ex-webby

It'll be interesting after the resulting discussions, how many *I've* got wrong!!

PS. This is probably obvious but, in the interests of being fair, it would probably be best not to discuss which ones we all think we have right or wrong until after the results have been published.

SUBTYPER

1) A

2) A

3) B

4) C

5) A

6) A

7) C

8) B

9) B

10) D

11) F

johnfelstead

yeh, i thought about that re not being able to say.

Should be a fun argu.....erm discusion about this later.

sammyh

iTrader: (1)

1=a)
2=a)
3=b)
4=a)
5=a)
6=a)
7=a)
8=b)
9=b)
10=b)
11=f)

bigsinky

i hope mycroft doesnt get a look in or we will be for the next 2 year discussing the ins and outs of vehicle dynamics

cheers

big sinky

Chris_P1

1. A
2. A
3. B
4. C
5. B
6. A
7. A
8. B
9. B
10. C
11. C

(Edited by webmaster to remove a potential clue)

Paul_M

1:A
2:A
3:B
4:C
5:B
6:A
7:A
8:B
9:B
10:A
11:E


Just like to say I answered all the questions before looking at anyone else's answers so as not to influence my decisions and find out how much (or little) I know about these things.

A good idea I'd say after seeing that John has the first reply! I think I'd definitely have done a bit of cheating had I seen that beforehand

RB5SCOTT

Here's mine

1:A

2:A

3:B

4:C

5:A

6:A

7:A

8:B

9:B

10:A

11:E



10 i am pondering most because it depends what transition state you are coming out of. It also depends whether you mean grip or traction, because in an AWD car you gain more traction making the front more usable, but in a RWD car you would gain more rear end grip. So for AWD i'll go with A, for RWD i'll go with C. Some good questions.

scrappydoo

1) A
2) A
3) B
4) C
5) B
6) A
7) A
8) B
9) B
10) B
11) E

chiark

1 A (would have said B, but then thought about it some more...)
2 A
3 B
4 C
5 B (you've seen my sub box, haven't you!)
6 A
7 A (depending on the effect of aerodynamics)
8 B (depending on so many other factors...)
9 B
10 D (? - stiffer front = less weight transfer = better grip at rear?)
11 (Mode=Ralf Wiggum) My cat's breath smells of cat food (/mode)

Can you tell us when we can have the answers, and the ensuing debate ?

scoobchrissy

iTrader: (1)

1 A
2 A
3 B
4 C
5 B
6 A
7 A
8 B
9 B
10 D
11 E

MarkT

1:a
2:a
3:b
4:c
5:b
6:a
7:a
8:b
9:b
10:a
11:e

madmoog

iTrader: (1)

Without having looked at anybody elses answers, but it's late and I've been in deep conversation with a nice South Africa Red...... here goes..

1 : b
2 : b
3 : b
4 : b
5 : a (unless rear engined i.e. Porsche or beetle)
6 : a
7 : a
8 : b
9 : b
10 : b?
11 : e

Chris L

1: A
2: A
3: B
4: C
5: A
6: A
7: A
8: B
9: B
10: B
11: No idea - B?

Chris

miles25

Well it's worth a try

1 : a
2 : a
3 : b
4 : c
5 : a
6 : a
7 : a
8 : b
9 : b
10 : b
11 : c

ex-webby

Hi All

Answers will be posted within the next couple of hours (maybe sooner, depending on time available).

Well done to everyone who's taken part so far.

Can we please be careful not to post any other comments apart from the answers until after the results have been published. eg "I would have said b but it depends on the angle of the dangle"

Cheers

Simon

coulty

1:A
2:A
3:B
4:C
5:A
6:A
7:A
8:B
9:B
10:A
11:E

ex-webby

Last chance.. Answers being typed up now, with explanations

ex-webby

Hi All

Well done to all that have taken part. Here are the answers with explanations. If you are not sure about any of the answers, or think they are wrong, this should start off healthy debate, so feel free to call me a liar!!

Question 1
You are competing in a circuit race and you car is fitted with a brake bias control. The heavens open and the circuit is wet within seconds and you're on a dry set-up. The only thing you are able to change is the brake bias, shoudl you.

a) Wind on more rear brakes
b) Wind on more front brakes

Answer a) Wind on more rear brakes.
This is contrary to instinct in many cases, as you would think you would want to be more careful not to lock up the rears. But the most important factor is that (Due to the reduced grip) you will have less weight transfer to the front wheels under braking, so therefore need less of your braking power going to the front wheels.

Question 2
Stiffening your front anti-roll bar will usually make the car tend more towards :

a) Understeer
b) Oversteer

Answer a) Understeer
The reason for this is that stiffening the front roll bar increases the amount of load transfer across the axle during cornering. As a general principle, the end of the car that shares the weight on each tyre the most evenly, will be the end that grips the most.

Question 3
Bump steer is :

a) The steering force created in the tyres when you hit a bump
b) The change in toe angle during bump and rebound travel of the suspension
c) Camber changes during the bump and rebound travel of the suspension

Answer b)
It is the change in toe angle as the suspension moves through it's range of travel. Named after the "bump" motion of the suspension (compressing suspension is in "bump", and extending is in "rebound").

Question 4
You are cornering in an standard AWD Impreza on the limit and all tyres are at the point of slipping. What course of action would most likely cause sudden oversteer.

a) Full throttle
b) Add more positive steering lock
c) Zero throttle

Answer c) Zero Throttle
The infamous Lift-Off-Oversteer. Transfering a little load to the front, and removing a little from the rear at the same time.

Question 5
Securely fixing something heavy into the boot of your car, is more likely to create

a) Understeer
b) Oversteer

Answer b) Oversteer (Shock Horror!!)
This should create a decent debate, and is widely mis-understood. In order to stop the rear of the car from sliding during cornering, the tyres need to be able to resist the mass that is acting on them (trying to go towards the outside of the bend - actually straight on, but never mind that!). Within the normal operating ranges of a tyre, as you double the load on a tyre, you less than double the grip (meaning (in this description) max lateral acceleration) it can produce. More mass, requires more grip to resist it, and the extra weight does not provide as much grip as is necessary. This is the main reason lighter cars are generall faster than heavier ones.


Question 6
The Subaru Impreza suspension arrangement is known as :

a) MacPherson strut
b) Wishbone
c) Leaf Spring

Answer a) MacPherson Strut

Question 7
Taking two cars of the same power to weight ratio, one weighing more than the other (so also having more power to compensate) which will have the highest top speed.

a) Heavier, more powerful car
b) Lighter, less powerful car
c) Both exactly the same

Answer a) Heavier, more powerful car
This is a really tricky one, and well done to those that got this correct. As the shape of the car is identical, the heavier more powerful car will have a better power to drag ratio. ie they will both encounter the same wind resistence, but the more powerful one will be able to counter it more easily.

Question 8
Taking the same two cars, which would be the fastest round a constant circle (like a roundabout).

a) Heavier, more powerful car
b) Lighter, less powerful car
c) Both exactly the same

Answer b) Lighter, less powerful car
For the same tyre reasons as in question 5. The tyres have less to resist, so the maximum cornering speed should be greater.

Question 9
Which will stop the quickest from 100MPH

a) Heavier, more powerful car
b) Lighter, less powerful car
c) Both exactly the same

Answer b) Lighter, less powerful car
Again, the tyre reasons. More weight means more grip, but not enough grip to counter the extra weight.

Question 10
What is the most likely effect on a car if you increase the rebound resistence of the front dampers

a) More front end grip under acceleration
b) More front end grip under braking
c) More rear end grip under acceleration
d) More rear end grip under braking

Answer c) More rear end grip under acceleration
This is a tricky one also. The reason for this is that increasing rebound resistence effectively lifts the front wheels off the ground (exaggerated, obviously) when the body of the car rolls backwards (under acceleration). This means that the weight of the car is being supported more by the rear tyres, which means more grip at the rear.

Question 11
During theoretical steady state cornering (not acceleraing, decelerating, etc) which of the following is most likely to caused more oversteer

a) More rear rebound resistence
b) More front rebound resistence
c) More rear bump resistence
d) More front bump resistence
e) More front negative camber
f) More rear negative camber

Answer e) More front negative camber
The reason for this is that "in general terms" adding negative camber will give some degree of increased cornering grip (this is in no way hard and fast as a rule, but it fairly likely to do this). The reason this weak reason is enough is that during theoretical steady state cornering there is no movement at all in the suspension, so therefore the dampers would not be operating or affecting any part of the handling.


---

I'll now go away and work out who's won

All the best

Simon

ex-webby

OK

The following people got all but one question correct each..

Chris P1
Paul M
scrappydoo
scoobychrissy

The following got all but 2 questions correct..

johnfelstead
hammyhamster
rb5scott
chiark
Chris L
coulty

Well done to all who took part

As Chris P1 was the first to post (out of the winners) he is crowned our first World Champion Driving Dynamics Guru

All the best

Simon

PS. To make it quick and easy to see which ones you got right and wrong the answers are :

1:A
2:A
3:B
4:C
5:B
6:A
7:A
8:B
9:B
10:C
11:E

Chris L

Not bad - the two I got wrong were complete guesses. Well done Chris P1

greasemonkey

I propose that this thread is both divisive and contrary to community spirit.

Not only has Felly been comprehensively deposed as the guru of Scoobynet chassis dynamics (two questions wrong?!), some of us were off playing at the Sunseeker and were thus unable to take part.

Now, if anyone wants a multiple choice quiz on the bowel-tightening properties of gravel tyres when used on a surface that is a mixture of snow or sheet ice, we have all the answers!

ex-webby

lol @ greasemonkey

john was probably just feeling a little off colour, there will be plenty more for him to regain his crown.

Sunseaker on gravel tyres would have been lots of fun. What kind of pant-slip angle were you running?

How many, if any, would you have got wrong greasemonkey?

Cheers

Simon