Reading Slicks.

[YLD-16L]

I'd reckon go to 2.5-3 negative camber, but seriously look for more castor, up to around 4-6 positive.

This will keep as much rubber on the road in a straight line to give you as much rubber for braking.

The castor will allow the wheel to camber up as you turn in and it will add more weight on the tyre (work the tyre harder) without the body roll taking the weight transfer.

It'd be interesting to measure the camber gain against steering angle because your idea was going to be my plan of attack on the front end of my car but I found the steering angle I would see on the track wasn't enough to gain a sufficient amount of neg camber on cornering.

I'm not familiar with the GT4(8) arrangement though so it may be better?

[Rodger]

Yeah suppose you right YLD, not enough gain (if any) for the amount of steering lock required on the track. Justen needs good castor though for tracking and return of the wheels to centre so he can then opposite lock quicker as he power oversteers

I must check to see if I gain much with 6 postive castor on the 22.

Regards

Rodger

[JustenGT8]

Justen,

Do you know the castor settings? Have you got power steering on it?

Keep in mind the current spec slick the V8 boys run has very very soft side walls so they need a lot of camber to off set the side wall flex.

I'd reckon go to 2.5-3 negative camber, but seriously look for more castor, up to around 4-6 positive.

This will keep as much rubber on the road in a straight line to give you as much rubber for braking.

The castor will allow the wheel to camber up as you turn in and it will add more weight on the tyre (work the tyre harder) without the body roll taking the weight transfer.

Regards

Rodger

Note to Dodge "read thread before posting"

Castor is fixed. Already at 2.5 neg.

No easy way to change castor and only way i can see is to move strut top back which isn't really the idea eh?

Camber pins to go in to add to strut top camber adjustment.

[Fish]

you want postive castor.

a hotter inside 3rd means to much neg camber. but would try a stiffer spring rate too

fyi the v8 taxi's run 5 deg's neg. my race car runs 3 deg neg and that give me good wear and cornering. i have 450lb fronts.

there is an easy way to check if pressures are to hot or too cold for the tyre. you have to read the grain.

A finely even grained surface across the width of the tyre means the tyres are working at its optimum.

a heavy grained deep rooted pattern across the tyre means its being over worked and that there is something wrong maybe a chassis problem ( you don't have more aero so don't worry) or the compund is too soft for your car.

heavy graining on one side of the tyre means either too much camber or too much toe.

a section of the tyre that is ungrained means too much camber. if the tyre is "polished" means the tyre isn't coming up to temp.

[JustenGT8]

you want postive castor.

a hotter inside 3rd means to much neg camber. but would try a stiffer spring rate too

fyi the v8 taxi's run 5 deg's neg. my race car runs 3 deg neg and that give me good wear and cornering. i have 450lb fronts.

there is an easy way to check if pressures are to hot or too cold for the tyre. you have to read the grain.

A finely even grained surface across the width of the tyre means the tyres are working at its optimum.

a heavy grained deep rooted pattern across the tyre means its being over worked and that there is something wrong maybe a chassis problem ( you don't have more aero so don't worry) or the compund is too soft for your car.

heavy graining on one side of the tyre means either too much camber or too much toe.

a section of the tyre that is ungrained means too much camber. if the tyre is "polished" means the tyre isn't coming up to temp.

Cheers, this is more what i was looking for. I'm not experienced enough with slicks to pick the difference in 'grain' you are referring too......i'll post some pics which i hope will be decipherable?

[Fish]

yeah mate.
send me a line to txc0upe at optusnet com au and i'll scan you some good reading too

with the grain if it looks the sand on the beach where the water has been its good.

if it looks like your back after you gf has copped a pounding then its bad grain.

pics to help...

bad tyre graining


good tyre

[Fish]

a good read here.

http://www.formulastudent.de/academy...ticle/tyres/2/

[JustenGT8]

Bingo

The outside of the tyre looks like the bottom pic and the inside looks like the top tyre...specifically the 'rippled' edge closest to the 'Hoosier' sidewall.

I'll get you some pics to confirm though.

[JustenGT8]

Uh oh

"Excessive Ackermann angle will wear the tyre by causing the inner tyre to be dragged across the turn apex."

This might not be good. A consequence of the front mount rack and the reversed stock steering knuckles was a crap Ackermann angle....for a street car not too much of an issue just a less than optimal scrub radius. Might be contributing to the slicks 'issues' though?

Going faster may be tougher than i though

[Fish]

nothing that sorting out the bump steer will fix i think or a good wheel alignment.

[JustenGT8]

No bump steer issues...we spent hours tweaking the rack position to get fark all toe change with bump and droop.....way better than stock. Ackermann is fixed so nought i can do about that?

[oldcorollas]

ackermann is changed by forwards/backwards positioning of rack..

bump steer is more about height and width of rack? (or so my tired mind is imagining) relative to the lower arm and steering arm.

ie, if you keep heigth and width same, you should be able to change ackermann with minimal change in bump steer...

but of course since there is castor and camber of strut/upright, when you turn, you are changing the requirements of rack height for zero bump etc...
thoughts?

edit:: noticed this when trawling
http://www.formulastudent.de/academy...ticle/tyres/1/
http://www.formulastudent.de/academy...ticle/tyres/2/
http://www.formulastudent.de/academy...ticle/tyres/3/


mmm Schallamach waves....

[JustenGT8]

Ackermann is based on the position of the rack end ie the steering knuckle...v'difficult to change?

[Fish]

could you use spacers?

[Fish]

bit late stewart with those links