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Crazy physics: Stopping ability does not increase with tyre width ... SOLVED!

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bajachris88 The international telephone dialing code for Antarctica is 6

6,661 posts · joined Apr 2005 ·

#639761
Pastit wrote:They say that people who "Intelchooilize" things are making up for inadequies in the "Bedroom flute" department. Any truth?🤓
hahaha

no comment 😂

yea, its a waste of time, but in the end, this is all locked in my mind now. ready for the uni physics quiz next week 🤓

uni sux
(ô_!_/ô) (ô_!_/ô)
69' baja: kombi box, thing spindles, irs, disc front, type 3 rear drums, 2 inch lift kit, 31x10 rears. 👍
New engine in process: 94mm p&bs, 74mm C/w chomol Crank, 35.5x39 SP heads, turbo. Wierd combo, hopeful torque monsta!

Pastit Seriously Crusin Dubber

150 posts · joined Feb 2008 ·

#639790
bajachris88 wrote:hahaha

no comment 😂

yea, its a waste of time, but in the end, this is all locked in my mind now. ready for the uni physics quiz next week 🤓

uni sux
You have a choice, go and cook burgers or maybe get one of those flashy dayglow vests and retrieve runaway shopping trolleys.........................or you could go to Uni, I think you've made the right one.

Going back to your other problem, there is help. The IMHSA (International Mens Half Size Association) is an association formed for the networking and fellowship of men with undersize genitals. I'm sure your Uni will have a local chapter or you could be like me and form your own. You will be surprised how many people you know who are so inflicted, our previous PM (That's where the term Lil Johnny came from) was a founding father of the Australian branch. So go forth and seek help, you need'nt suffer alone.🙅

sinecure Want another... :(

1,031 posts · joined Mar 2006 ·

#639989
bajachris88 wrote:As for tyre to road friction, despite whether braking mechanisms are working or not, they all only retard the spinning of the wheels, not the car's velocity. The only thing that slows down the car is the friction between the bitumen and the tyre, otherwise the wheels would consistantly lock up due to the braking mechanisms and hence the car would keep sliding along the road (if friction was very small)

If the car was rolling to a stop, or braking suddenly, it will always be using the road as its only base for stopping.
Thanks mate! I KNEW I'd screwed something up there, just couldn't figure out what 🤪
A POSSE AD ESSE.

I live in my own little world, but it's okay, they know me here.

Baja Wes V6 Baja Pioneer

3,119 posts · joined Aug 2002 ·

#640455
What if i told ya that the stopping ability of your car never increases with wider tyres, nor with extra weight above?
....

Function 2: f = u x n (f, being the friction force. I couldn't find the funky u symbol for the coefficient of friction, however thats what the u stands for.
Unfortunately your statement and the title of this thread is incorrect.

The friction function shown is an approximation and the fraction values used in it are empirical.

To calculate the friction more accurately takes into account a whole lot more variables that simply aren't in the simplified equation. These more complex variables include contact patch area and pressure. This is because you start having molecular adhesion and deformation of the tyre itself. The simple equation is the most correct for hard on hard sliding surfaces.

The tire companies keep the more complicated equations secret as they use them for racing where they compete against each other.

Widers tyres have more grip, and lower tyre pressures increase the tyre contact patch also giving more grip. But there is a limit to both of those too. If you inflate your tyres to 50psi you'll notice your contact patch will be very small and you won't get much grip. But this same tyre with the same rubber compound will have more grip at 30psi with the larger contact patch.

If you want to see how complicated the tyre friction can get have a look at this;
http://hal.inria.fr/docs/00/05/14/75/PDF/vsd05.pdf

or just google "Pacejka's magic formula"
Wes - www.offroadvw.net - 200HP Quad Cam V6 in a VW Baja - with climate control... 🙂
www.taylorcycles.com.au - My DH MTB racing brothers shop.

Volkswagenboy Staggers Automotive.

2,437 posts · joined Jul 2005 ·

#640483
bajachris88 wrote:Its a good topic, we need baja wes in here as well.
Ah there he is!!!
-Staggers.
STAGGERS AUTOMOTIVE - Heavy Vehicle Diesel Specialist
JB CUSTOMS & CLASSICS - Car Builders
2/53 Tradelink Drive, Browns Plains

camando Commited Dubber

52 posts · joined Jun 2006 ·

#640546
Great topic.
But you forgot Static friction.

Static friction is the coeffiecient between two surfaces not moving in relation to each other.
This coeffiecient is greater than Kinetic friction (slip).
Depending where you look up to ~0.8 for wide soft tyres on a good road.
Down to ~0.4 for Kinetic friction

This is why ABS stops you quicker than locking up.
Or burnouts get you no where.

Static friction is more closely related to contact area as the electric charge between the molecules from the different surfaces can create a better bond.

Hence why F1 went for grooved tyres to reduce grip (speed).

Volkswagenboy Staggers Automotive.

2,437 posts · joined Jul 2005 ·

#640826
Baja Wes wrote:Better late than never hey 🙂
Yep!!!
😂😂
-Staggers.
STAGGERS AUTOMOTIVE - Heavy Vehicle Diesel Specialist
JB CUSTOMS & CLASSICS - Car Builders
2/53 Tradelink Drive, Browns Plains