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Tyres, traction, G force etc..
zilspeed - 27/8/05 at 05:57 PM

New tyres fitted to the GTM.
Yokohama A-032Rs on the front
Yokohama A-008Rs on the back.

Now.......

Some of you may remember my trials and tribulations with the car as regards handling, tail-happiness etc... and the fact that I have literally just got the engine back and running health again - healthier than ever in fact.

My question.
Today on the way home from the hillclimb where I had been marshalling I found a bit of flat dry and smooth deserted tarmac. So, I stopped, dialed in 4500rpm and tried a launch. Before, on the old tyres the clutch would have bit hard and the wheelspin would have taken care of the launch. Today was different though. Not a whiff of wheelspin - even with the stronger engine and clutch slip for the first time ever.
My point is, will this new found and frankly phenomenal traction be translated into cornering grip or is it not quite as simple as that ?

Any thoughts, anyone ?



[Edited on 27/8/05 by zilspeed]


Northy - 27/8/05 at 06:07 PM

Sounds to me like it'll be translated into a new clutch soon!


britishtrident - 28/8/05 at 04:05 PM

Yes --- if the extra grip comes soley from the compound -- but the tyre construction and tread pattern play big part -- generally road tyres have more grip fore/aft (traction/braking) than lateral (cornering).

Plotted out on a graph the maximum combination of cornering and acceleration load the tyre can sustain will give an ellipse --- not disimilar in concept to Mohrs circle.

From it you could work out the maximum cornering g the tyre could sustan at a give acceleration. Of course in the real world it isn't that simple but thats the general concept.


britishtrident - 28/8/05 at 04:07 PM

I should add take care of the clutch -- the Valeo clutch on the 1.4 k series ain't exactly big & butch.


zilspeed - 28/8/05 at 05:06 PM

Minor update.....

Today at Forrestburn was wet wet wet...
Well, it improved to dampish in the afternoon. Traction was nothing like as good off the line, but my God what a difference decent tyres makes. I stil had to fiddle with pressures to sort it out a bit, but it is all moving in the right direction. All very pleasing.
Started off the day dog slow and found 13 seconds of improvements as the day progressed. All in 4-5 second cunks.


SeaBass - 28/8/05 at 07:11 PM

Good effort mate. Your first hillclimb eh? Shame I wasn't there to see it. Callander classic was rained out again this weekend... I'll see if I can find those pics of you stood at the start line the other night lol ...

Cheers

[Edited on 28/8/05 by SeaBass]


zilspeed - 28/8/05 at 09:26 PM

quote:
Originally posted by SeaBass
Good effort mate. Your first hillclimb eh? Shame I wasn't there to see it. Callander classic was rained out again this weekend... I'll see if I can find those pics of you stood at the start line the other night lol ...

Cheers

[Edited on 28/8/05 by SeaBass]



Yep - first hillclimb. Ended up just over 64s. Miles off the pace of the megabusas, but they're down among the single seaters though....
It seems there is a possibility that bike engined cars will be shipped off into a class of their own for next year. Let's hope so.

Regarding those pics. I can hardly wait...


britishtrident - 29/8/05 at 03:13 PM

Of all the hillclimbs Doune is the danglers
I loved Doune -- the top bit not so much the botom section. Trouble is every time i go there I get reminded of what happened to Norrie Galbraith --- a good guy


DarrenW - 30/8/05 at 02:16 PM

Its a shame you didnt have a DD2 fitted Zil. You could have plotted before and after G-forces and also datalogged a 'track' section so you can see the tangible improvements.