How do you interpret the surface tyre wear on slicks

[slipstream]

Howdy fellow racecar lovers!
Can anyone point me in the direction of reading and interpreting surface tyre wear (any good educated read via web or book, pictures of what to look for would be a great bonus). Iam a mechanic working my way up the formula stakes, i can prepare a great racecar but my understanding of racecar dynamics is errrr a little weak, soooo i guess the best place for me to start is understanding what a slick tyre is telling me. One thing i ask engineers is the blops of pick-up that usually appear on inside front tyres, some engineers tell me its pick-up, some tell me its the actual tyre rubber running itself off from to much sliding which then looks like pick-up, actually i showed same tyre to 2 different race engineers and recieved the answers i just described....doh now Iam confused. What i do know is that some engineers disguise there lack of knowledge by just blinding a budding mechanic with various answers, anyway I would appreciate good advice from those who understand what iam on about

S

[Carlos]

The Racing and High Performance Tire by Paul Haney
http://insideracingtechnology.com/booktiredescrptn.htm
Take a look at the 3 excerpts from the book, a lot of information there, the book's expensive, if you wanted a copy a used book site like Abebooks might have it a lot cheaper.

Here's another good article, mostly on the importance of tire temperatures:
http://www.porschenet.com/bfgtires.html

[TudorMiron]

Both engineers may be telling you the true. With more experience you may find out that there are no hard rules in racing. Rules of thumb may be.
Use your logic. Does your car understeer too much (data backed by good proper driver debreathing or other way around? Whats the difference between front/rear tire temps and more importantly (if you don't run tire temp sensors)pressure rise? If it's picked up marbels than why they are not present on rears. etc., etc. You say - inside front tire - do you race on ovals?

Cheers
Ted

[Giblet]

Taking accurate pressure, plus inside, middle, and outside size measurements before and after the race for each tire can also tell you volumes.

Even someone who is not an engineer can use this to tell where the car is working too hard or not hard enough for the track.

Sometimes setting up a basic scientific test method looking at the handling like an experiment with variables and constants can give you a baseline to work from, instead of laptimes and feel.

[Krispy]

The Racing and High Performance Tire by Paul Haney
http://insideracingtechnology.com/booktiredescrptn.htm

Paul Haney is a brilliant man. I had a chance to talk with him about tyres and suspension design and he is very approachable. He explained a few things to me that he didn't understand fully when he wrote that book (front and rear roll center timing)But he has a wonderful grasp on the concepts now. At first I thought the book was too old to be of much use however the concepts that are explained in the book are extremely applicable even today. I am now proud to say that I have an autographed copy of the book in my possession.

A lot of reading a tyre comes from experience with that particular car/tyre combination. The best advice I have heard is to consistently record data and make notes of what your tire data is when you are winning races (putting down fast laps) and shoot for that every time. Every car,tyre, and driver will want a little something different to make it work right for them. Just be sure to log temperatures, pressures, and lap times and you should get a good idea of where you are and where you need to go.

[marcush.]

thats an easy one to answer:

pickup is a function of too slow driving and too low tyre temps.You need to know which is the best tyre temp,and which temps you don´t want to see when coming into your pit slot be it high or low.
Usually ,on a green track on test days ,theres not much rubber laid down and you don´t have a lot of pickup.But on a busy track its a whole different story.
When you don´t push ,or you drive too much off line you are very likely to pick up everything .Also wrong balance(setup or else) may avoid getting tyre temps up on one axle causing pickup.
If the driver is unable to get rid of the pickup you have to help him setupwise(more toe,scrub),or delete at least some of the precise rosejoints,and use rubber to create the scrub (and heat)artificially...
A main point here is :under the pickup you will find the tyre surface and how it worked .
So first thing when analysing the tyre is to scape off the pickup and look at the tyre surface.Dont wait too long or you will need a heatgun to get that job done.
Then you look at the surface texture across the whole thread ,and the sign of a very fine grain spread out evenly over the complete surface width is a good start
of course you should have taken notes how much thread you started with so you have a clear idea how much is worn off where in which time at which conditions,and of course massively wrong suspension settings.
The knowledge base you are building up when checking all this ,plus cold plus warm pressures plus tire temps everytime the car comes to a rest (including ambient and track temps) will make a huge difference under changing conditions ,but for sure this is going to keep one guy very much on his toes on a typical day at the track when you try to keep record of all this.
I usually make notes on a prepared small notepad,and put the accumulated data into excel sheets.If you run the same tyre on the same track usually,you can get to a point to put in ambient temps and track temps,laps to be covered ,new or used tyre and come up with cold pressure settings spot on.
Paul Haneys book is definitely a musthave !I highly recommend it.

[slipstream]

Cheers chaps, will take all that into account and study a little more

[Richard]

Came across this wonderful theead by accident. What delightful technical conversation, hence this bump

[Jersey Tom]

SMH..

[Jon]

SMH..

Don't agree? Can you elaborate on that a bit JT???

[Jersey Tom]

Just don't agree with a lot in Haney's book.