Reddit reviews Race Car Vehicle Dynamics - Problems, Answers and Experiments

Again, please stop trying to apply your physics 1 understanding of friction to this. The way friction is taught in a course like that is completely inaccurate and flat WRONG with how friction and tires actually work. It would be like trying to newtonian physics in astronomy, where relativity is incredibly important.

Have you ever stopped to think and ask why sports cars have wide tires? According to your sources and the physics 1 modelling of friction, surface area has no factor in lateral force, so why would they ever want to have those big, heavy, wide tires when they could just get nice skinny and light ones which get the same amount of grip? Its because friction is a nightmarishly complicated topic and all of those numbers youre looking at are at best rough ballpark guesstimates dont hold up in reality.

First off, in YOUR OWN SOURCE, there are items in there with higher than 1 coefficient of frictions, so its clear that even the completely basic (and wrong) understanding of friction isnt bounded at 1.

Second, there are a ton of readily available examples of street cars exceeding 1G in acceleration, braking, and cornering. Basically every reasonably quick sports car today has a higher than 1G skidpad, most of which dont generate any downforce, and even the ones that do arent generating anything meaningful at skidpad speeds. Under your assumption it would be literally impossible for the corvette z06 to hit the 1.2G on a skidpad that it did in car and driver's test. The Tesla model S also would not be able to hit its 0-60 time of 2.3 seconds, and it definitely isnt generating downforce. On top of that, basically every car on the market can hit >1 peak braking Gs.

third, "you dont increase the u" is completely wrong. u is an ungodly complicated variable which depends on temperature, chemistry, surface conditions, surface properties, deformation, contact angle, system dynamics, and funny enough the normal force as well. Its why you have to warm up a racing tire, its why race tires use very different rubber compounds and construction methods than street tires, its why racing brakes dont work worth a shit the first few times you try to stop, its why vehicle suspension matters, its why vehicle weight matters in a corner.

Start on page 13 to start learning about how tires and friction actually work then after youve read that book about 10 times go buy race car vehicle dynamics and read that about 5 times. Then go work on a racing team for 5 years, then come back and talk to me about your understanding of friction.

Totally forgot about this test! Hard to believe it was only 3 years ago.

From what I remember, I did the acceleration testing and one of the other test drivers did the handling testing. Essentially the 1LE performed identically on both tires. The figure eight test is so short that the 0.03 avg lat g difference is basically noise.

Much of the reasoning why has to do with optimization of the suspension for a given tire. I won't pretend to be an expert on suspension setup, so I'll point you here: https://www.amazon.com/Race-Car-Vehicle-Dynamics-Experiments/dp/0768011272

This question has been asked a bunch of times, but the one post I've found the most helpful was /u/that_video_art_guy's response in this post. For quick reference, here's the copy/paste:



I've read many of these books, I'm partial to the mechanics and team member books but find all of them to be very enjoyable.


The Super Collective Super list of Super Good F1 Books:

Mechanics/Team Members


[Life in the Pit Lane: Mechanic's Story of the Benetton Grand Prix Year](
http://www.amazon.com/Life-Pit-Lane-Mechanics-Benetton/dp/0760300267/ref=sr_1_5?s=books&ie=UTF8&qid=1356716346&sr=1-5&keywords=steve+matchett) - Steve Matchett

[The Mechanic's Tale: Life in the Pit-Lanes of Formula One](
http://www.amazon.com/Mechanics-Tale-Life-Pit-Lanes-Formula/dp/0752827839/ref=sr_1_1?s=books&ie=UTF8&qid=1356716346&sr=1-1&keywords=steve+matchett) - Steve Matchett

The Chariot Makers: Assembling the Perfect Formula 1 Car - Steve Matchett

Team Lotus: My View From the Pitwall - Peter Warr

Jo Ramirez: Memoirs of a Racing Man - Jo Ramirez

Art of War - Five Years in Formula One - Max Mosley, Adam Parr, Paul Tinker

Tales from the Toolbox: A Collection of Behind-the-Scenes Tales from Grand Prix Mechanics - Michael Oliver, Jackie Stewart


Technical Books

Red Bull Racing F1 Car: Haynes Owners' Workshop Manual

McLaren M23: 1973 Haynes Owners' Workshop Manual

Lotus 72: 1970 Haynes Owners' Workshop Manual

Tune to Win: The art and science of race car development and tuning - Carroll Smith

Engineer to Win - Carroll Smith

Nuts, Bolts, Fasteners and Plumbing Handbook AKA: Screw to Win - Carroll Smith

Race Car Vehicle Dynamics: Problems, Answers and Experiments - Doug Milliken

Chassis Design: Principles and Analysis - William F. Milliken, Douglas L. Milliken, Maurice Olley

The Racing & High-Performance Tire: Using Tires to Tune for Grip & Balance - Paul Haney


Technical Driving

Ultimate Speed Secrets: The Complete Guide to High-Performance and Race Driving - Ross Bentley

Going Faster! Mastering the Art of Race Driving - Carl Lopez

Working the Wheel - Martin Brundle


Drivers and Rivalry's

Senna Versus Prost: The Story of the Most Deadly Rivalry in Formula One - Malcolm Folley

The Limit: Life and Death on the 1961 Grand Prix Circuit - Michael Cannell

Winning Is Not Enough: The Autobiography - Sir Jackie Stewart

Shunt: The Story of James Hunt - Tom Rubython

Alex Zanardi: My Sweetest Victory: A Memoir of Racing Success, Adversity, and Courage - Alex Zanardi, Gianluca Gasparini, Mario Andretti.

It Is What It Is: The Autobiography - David Coulthard

Flat Out, Flat Broke: Formula 1 the Hard Way! - Perry McCarthy The Black Stig, Damon Hill

F1 Through the Eyes of Damon Hill: Inside the World of Formula 1 - Damon Hill, Photography: Sutton Images


People Of F1

Life at the Limit: Triumph and Tragedy in Formula One - Professor Sid Watkins

Beyond the Limit - Professor Sid Watkins

I Just Made The Tea: Tales from 30 years inside Formula 1 - Di Spires

Bernie: The Biography of Bernie Ecclestone - Susan Watkins


Picture Books

McLaren The Cars: Updated 2011 Edition

Art of the Formula 1 Race Car - Stuart Codling, James Mann, Peter Windsor, Gordon Murray

Here are the two best intro books on the subject:

https://www.amazon.com/Race-Car-Vehicle-Dynamics-Experiments/dp/0768011272

https://www.amazon.com/Fundamentals-Vehicle-Dynamics-Premiere-Books/dp/1560911999

Formula SAE in college is a great resource. Look for a co-op opportunity in vehicle design (it'll probably have to be in Michigan unless you're lucky or go into commercial truck). Experience is highly valued when you're trying to get that intro level job because co-ops and internships are so widely available in the industry.

http://www.amazon.com/Race-Car-Vehicle-Dynamics-Experiments/dp/0768011272

http://www.amazon.com/Racing-Chassis-Suspension-Design-PT-90/dp/0768011205


Can't learn suspension design without chassis design!

Find the Milliken book. Aka, this one.

The 'bible' for vehicle dynamics is the Milliken and Milliken Race Car Vehicle Dynamics which has all the relevant equations and analysis to show how vehicles work. It's a really good book.

If you're looking for more of an intro book, and not so much detalied mathematical description, Gillespie's Fundamentals of Vehicle Dynamics.

https://www.amazon.com/Race-Car-Vehicle-Dynamics-Experiments/dp/0768011272

Though not really applicable to the engine side, and likely too conceptual for the tire wear models, this one is really good from the dynamics side and translates many aerospace concepts over to vehicle dynamics (Stability derivatives, etc.):

Race Car Vehicle Dynamics, Milliken & Milliken

Do you have any good links for more information? I see what /u/Wozrop is saying from the theoretical model of friction standpoint but I see a ton of empirical evidence to backup what you're saying—and no doubt racers know this. I'm basically looking for technical explanations of why this is the case.

Edit: Incase anyone cares (or even reads this) I found an excerpt from Race Car Vehicle Dynamics:

>Tractive force F_T and braking force F_B are a function of slip ratio. As the slip ratio increases (numerically) from zero, the forces rise rapidly to a maximum which usually occurs in the range of 0.10 to 0.15 slip ratio, after which the forces fall off.

So, yeah, Milliken's 10-15% slip ratio finding corroborates /u/Kkubaa's statement. The chapter on Tire Behavior is pretty interesting; a lot more going on than simple problems from undergrad mechanical engineering.

back in the 90s I got paid to do the dynamics on a racing game.

so much fun.

hardest part was understanding impulse vs. force applied, keeping the time dimension straight.

plus figuring out the axis of rotation of wheeled vehicles, how exactly tires turn a car.

https://www.amazon.com/Race-Car-Vehicle-Dynamics-Experiments/dp/0768011272 is the bible of course but it didn't answer any of the hard problems I ran into, like how to transfer the (uneven) forces in the shocks into angular vs. vertical acceleration.