ex-webby

Dear all

The first of many technical articles on various aspects of car performance has arrived as a new-year treat!

enjoy..

http://bbs.scoobynet.co.uk/article.php?a=tyres&p=1

Please feel free to post any questions or feedback in this thread.

Jamo

iTrader: (23)

wow!!! have you written all that? I have just flicked through it, but will read it in more depth when I get more time. I must say I am well impressed though

ALi-B

iTrader: (1)

So.....which is the best tyre for the UK's constantly wet and diesel covered roads?

Floyd

iTrader: (9)

I'm confused!

How could you test a particular tyre and suspension set up consistently? Is it as simple as doing circles at the break away point and recording the speed - the higher the speed for a given circle = better set up?

F

ex-webby

Hi Gents

Thanks for the comments.

Floyd

Do you mean in order to work out the slip angle graphs, etc?

When testing tyres, the first proper testing happens in the lab. Imagine the the tyre mounted on a wheel which is attached to a kind of rolling road machine. The wheel is then turned through different angles at different vertical loads, different cambers, etc. and the lateral forces measured.

As with everything related to tyres though, this only gives you a starting point and things can change once you get them out into the real world.

SDB

Bob Rawle

Well presented I must say, I've had the good (or bad) fortune to be able to try different tyres regularly due to the high mileage I have historically done, of all the tyres I've tried the best without doubt for me have been the current set which are Dunlop Super Sport Race, now they are definately not suitable for use in any standing water but suprisingly do better (for me) in normal damp/wet conditions than most others I have used. The striking thing though is the wear rate, the construction is clearly different to a road one as the tread is wearing evenly across its width without excessive shoulder scrub, side walls must be stronger to resist this yet, being a soft compund, the lateral forces are very much higher. This relates particularly to contact patch and vertical loading I think, interestingly despite only having 6mm tread depth instead of the normal 8 they have lasted me about 9000 miles so far with 2.8mm tread left, that included 45 or so full throttle launches in the TOTB period. On full lock the tyre tries to "jump" the rim which is a sign of grip.

I have also used Goodyear F1's, Falken, S03's, S02's, Toyos and Uniroyal (big mistake).

Anyone any views on the real differences between race and road construction as that seems to make a big difference to my usage and confidence.

Bob

911

Bob:
Are these Dunlops the D10J type?
Can you be more specific on the benefits youv'e noticed, ie performance from cold?
Are there any data numbers on the side walls, especially Traction (ie AA) and wear rate ie 80?

To my knowlege, the Dunlops are radial lay and nothing more.

Graham

bugeyewrx

911
I think Bob's talking about these camskill tyres they're not the same as the D10J .

I was about to order a set for trackdays , nice to hear some positive feedback on them .

Great article too

Martin .

Bob Rawle

Actually no they are non of these, wear number is 60 A A, these are they
http://www.tirerack.com/tires/tires....per+Sport+Race

bob

JohnS

iTrader: (1)

I've also used a set of these last year. Would agree with Bob's comments about the standing water.

In they dry they give amazing grip levels, and were OK on damp surfaces.

I would say in the dry the offered similar grip (probably better actually) than the Bridgestone RE-070s, but without the same side effects of tramlining on poor surfaces, road noise and a significant reduciton in ride quality (my in car CD skips over certain bumps when running on RE-070s). I used the Dunlops on several track events, and there was still a lot of life left in them when they were passed onto other for evaluation.

On smooth dry tarmac, when the RE-070s get warmed up they give fantastic steering response, which the Dunlops didn't quite match. I would say that the Dunlops are better overall for general road/fast road/occasional track use, where the RE-070s are better on super smooth dry roads and regular track use.

John

911

They do not sound like a hill climb tyre though?
Still think the Kumho v700 series are. (IMHO)
Graham

Thanks for the info though Bob!

STIUK

You should be able to find any of these tyres at a cheap price on www.top-tread-tyres.co.uk. If they're not listed email them and they'll get you price back very quick!

Cosmic37

Thanks very much for your interesting article.

Its nice to see some technical articles like this on scoobynet. Does scoobynet have a technical archive for articles like this? That would be really good.

Just one question - where does that formula come from?
"imaginary formula of :
tyre_limit_lat_acc / car_mass = car_cornering_ability"

It doesn't seem meaningful to me because it describes a quantity acceleration divided by mass. If it were force divided by mass obviously that would be an acceleration, something more tangible...