Curmudgeon
Curmudgeon MegaDork
4/13/13 6:54 p.m.

Slapped some bias ply slicks on the Jensenator, man they grip like an alien facehugger but they don't respond to steering inputs anything like a DOT radial. I have the alignment specs, tire pressures and tire temps down pretty good, discovered they want a lot more slip angle than I'm used to and braking becomes a whole new thing; momentum conservation is definitely necessary. I know for sure I need to put some more time on them to get really comfortable with them, in the meantime does anybody have any pointers?

Giant Purple Snorklewacker
Giant Purple Snorklewacker MegaDork
4/13/13 9:14 p.m.

Slide those berkeleyers like a Jim Clark wannabe. No E36 M3, those tires want you to drive sideways right on the edge and with smooth transitions.

The polar opposite of radial slicks with regard to slithering around.

Streetwiseguy
Streetwiseguy UltraDork
4/13/13 11:16 p.m.

The very first thing I ever drove on bias ply slicks was the super late model a couple of years ago. Yowza. More slip angle for sure, and the tires move around under the chassis a lot more. Squirmy...

poopshovel
poopshovel UltimaDork
4/13/13 11:39 p.m.

I know you said you've got the pressures on lock. Have you thrown a pyrometer on 'em? I ran 27/24 on the crx.

SkinnyG
SkinnyG HalfDork
4/14/13 12:32 a.m.

I run around 13psi on the Lethal Locost :)

Curmudgeon
Curmudgeon MegaDork
4/14/13 8:00 a.m.

Yessir, the thing is squirmy and grippy at the same time, which sounds weird but is true. I was advised by an old time Formula Ford guy to not try to be precise, that helped a LOT. He also said the hell with the tire pressures, set 'em once in the morning then fuggedaboutit. I'm a bit OCD, so of course I checked/bled. They picked up about 3.5 PSI on the first run then almost nothing on the last 3.

At 22 psi, the digital pyrometer says I'm right on the money and given the grip I tend to believe it, lateral G forces made me wonder if I was gonna pass out. Or maybe that was just the previous night's beer. Of course, that's based on my radial tire experience, maybe I'm looking for something different on bias ply.

One odd thing: it's a stick axle with no negative camber but the inside of the right rear tire was ~13 degrees hotter than the outside, the left rear was ~9 degrees hotter. The limited slip is weak, I heard it spin a couple of times in hard right turns which explains why the RR was hotter than the rest, but more on the inside? I'm running ~.5 degrees negative on the front which gives me approx 11 degrees hotter on the inside, which makes sense. But why the rear temp variation across the tire? Final run temps:

The last hard turn on the course was a left hander under power which explains the hotter right front temp.

My car weighs in at ~1800 pounds, how much does the Lethal Locost weigh?

GameboyRMH
GameboyRMH UltimaDork
4/14/13 8:08 a.m.
Curmudgeon wrote: One odd thing: it's a stick axle with no negative camber but the inside of the right rear tire was ~13 degrees hotter than the outside, the left rear was ~9 degrees hotter. The limited slip is weak, I heard it spin a couple of times in hard right turns which explains why the RR was hotter than the rest, but more on the inside? I'm running ~.5 degrees negative on the front which gives me approx 11 degrees hotter on the inside, which makes sense. But why the rear temp variation across the tire? Final run temps:

Makes sense, when you lift the right rear in a turn the inside of the tire is going to have the best contact on a solid-axle vehicle, when you spin the tire this part is going to get hot the fastest. If you look at how solid-axle offroad trucks corner on pavement it's easy to see.

Curmudgeon
Curmudgeon MegaDork
4/14/13 9:18 a.m.

Ya know, now that you mention it that makes sense. The axle is going to 'lean' for lack of a better term and that's going to take load off the outside of the inside tire. So I'm not chasing something weird, then.

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