[DeTomaso] Impressive grip

[Jerry Knotts]

As usual it is great to see you "go for it".  OHHHHH  Another small 
speed bump for mankind.

jerry knotts


On 7/15/2013 10:11 PM, David Fisher wrote:
> I took the car out for a spirited (as in my neck hasn't compained this much since karting) drive down my favorite, very twisty back road early Sunday.
>
> I had the benefit that the local cyclists were few, and the traffic was non existant - although the suicidal gophers were a plenty. (what is it with gophers playing chicken?!)
>
> Well, the long and short of it is that this 40 year old car is pretty darn entertaining!  I still have a rather lazy motor out back, but the new sticky rubber up front along with a rebuilt suspension makes for car with pretty darn high cornering forces, and it is actually feeling like a mid engine car now.  I have mild understeer at the limit, but the limit is pretty high.
>
> Two gophers gave their lives for my Sunday drive, and I would like to hold a moment of silence to thank them for making it even more entertaining.  ;-)
>
>
> Sent from my iPad
>
> On Jul 12, 2013, at 11:05 PM, JDeRyke at aol.com wrote:
>
>> Stock alignment #s were designed for narrow, hard, belted-bias tires; radials didn't come into use until the mid-'70s. So most factory settings are wrong for good handling especially with wide radials. But Camber, the amount a tire leans in or out from the vertical, should still be pretty close to zero for best tire life. Running -1.5 degrees will wear the inside edges faster than the rest of the tire. It will also improve cornering power noticably. If you're happy with the way the car rides and handles at this setting, and you periodically rotate the tires on the wheels (not side to side on the same wheels)  to compensate for inner edge-wear (or can afford to replace them when the edges are worn throug), then go ahead.
>>
>> With understeer in corners, you're running into the stock-fendered Pantera's main weak spot: you simply cannot hang enough front tire under an uncut front end to balance ultrawide rears. Thats why the GR-4 racers got big flairs. Your rear meats are more than 1.5X as wide as the fronts, so even if you've realigned things to compensate for our car's designed-in understeer, ultrawide rear tires will only intensify the understeer. Several things come to mind that you may already have done (in increasing order of cost):
>> 1)- run a 1" rear swaybar with a stock or slightly smaller od front bar. A hollow 7/8" front bar is 10% softer than a stock solid 7/8" bar. Poly center bushings intensify any antisway bar's action, and sphere-balls on the ends of both will improve the action noticably.
>> 2)- Check your ZF to be sure its not a 75% locker with 4 friction clutches per side. Most Panteras got a 45% locker (three discs per side) but not all. Unfortunately, disassembly is the only way to positively tell, but testing may give a clue. Too much rear lockup will cause corner-push in any car. Adding some Antislip agent to your ZF lube may help the push a little.
>> 3A)- Use a 245-35x 17 front (8.4" tread width). Your current fronts are 8.0"
>> 3B)- Use a 315-45 x 17 rear (11.4" tread width) . Your current rears are 12.2"
>> If you change both tires as above, the mismatch in width will only(!) be 1.35 and your odometer will read closer to correct, too. I'm curious about how all this plays out; most guys that mount giant rear tires don't much care about cornering. Keep me informed- I'd like to know if you solve the issue. Maybe I can learn something, too.
>> FWIW, I run 245-50 x 15s in front (8.9" tread) and 295-50x 15 rears (10.9" tread) with a 3/4" hollow front bar & a 1" hollow rear bar, both with poly bushings & sphere-balls. Those tread size ratios are 1.22:1. Stock ratio was  only 1.09:1
>> Cheers- J Deryke
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