No traction at all and rear end question

[allen123]

Alright my truck gets no traction what so ever. It has brand new 295/50's on the back but when its raining if i barely hit the gas the tires just break loose and i have to let off the gas completly because once they start spinning you cant feather out the throttle to stop it, you have to let off and let it stop.

And also i've asked before but does anyone know why my truck will sometimes posi up and sometimes do a peg leg?
Like everytime i leave school we all get on it and mine everytime will spin them both and throw me sideways but other times it will just do one side, and everytime when it rains it will spin them both, and it spins both in reverse. It is a 12 bolt but thats all i know about.

Just wondering if anyone would know.
thanks!

[71tahoe]

I'll guess it isn't a posi. An open diff will spin both tires.

Also:
1. Your wide tires have less downward pressure per square inch than narrow tires.
2. The coeffecient of sliding friction is always less than starting friction. Add a lubricant (water) and it lowers more. Friction = grip.
3. There's no weight in the rear end. Weight addes downward pressure and increases friction at the pavement.
4. You could spin forever.

[cdowns]

what are your tire pressures

[Longhorn Man]

unless you have an engine with some 300 ft pounds of torque at 1200 RPM, then I say it is the driver's right foot making the tires spin.
This isn't like the drivers ed 2005 toyota that has 112 horses. On that car, you just floor it from a stop and it takes off. Not enough power to spin the tires. This truck was built back when people learned how to drive cars, as opposed to how people are tought to operate cars today.

[mclairmo]

Add about 500 pounds to the back of the bed.

[mtdave2]

my 5000 pound long horn isnt worth a dam in snow, ice, or mud. it will spin the tires very easy. i do see a posi in the truck before long.

[woodchip]

I have a 1968 Chevy LWb,with a 396 eng 400 trans. When i start off ,wet or dry the wheels don't spin.I run 25 lbs in the rear tires, no posi. Like longhorn said its how you drive.. Now if I get on it , it will spin.

[kelsfine69]

Mayby its got 4:11's in it?

[woodchip]

I just wanted to add I have M+S P235/75R15 tires on the truck,also when I own this truck back in the 1970s I drove in the snow to work many many times. Just put about 10 8inch cement blocks over the rear axle and go. It has a 373 rear end.

[allen123]

I do have a heavy foot but im really not getting on it that i hard, i'll just drive off at a normal rate of speed and the tires just start spinning, and my truck does have quite a bit of power, it has a built 350 that i dont know much whats done internally, but i do know it has a pretty big cam and domed pistons, thats all that i know of now, but im going to be tearing it down soon

[SactoJim]

Just pull a couple plug wires every time it rains.

[WyoGMC]

What make and type of tires do you have? I had 305 Pirelli's P Zeros and those are way bad for traction in wet conditions. I was turning in a wet concrete parking lot, just idling and it pushed the front end. Driving in water was just about the same as driving on ice.

Point is if you have a performance tire you give up alot of your wet traction compared to an all season tire.

[unclewatts]

Originally Posted by WyoGMC

What make and type of tires do you have? I had 305 Pirelli's P Zeros and those are way bad for traction in wet conditions. I was turning in a wet concrete parking lot, just idling and it pushed the front end. Driving in water was just about the same as driving on ice.

Point is if you have a performance tire you give up alot of your wet traction compared to an all season tire.

Right on WyoGMC. That's what I was gonna say. The tread formulation and tread design go a long ways in determining a tire's wet traction. BTW, Posi is not a cure all. I have a GM corporate Posi rear end and if I get on a slick road or dirt and punch it the whole rear end of the truck wants to come around to the front and I got heavy cleated off road type tires on it. The solution is to get a set of better performance rain tires and stay off of it until you do.

[LONGHAIR]

Originally Posted by unclewatts

BTW, Posi is not a cure all. I have a GM corporate Posi rear end and if I get on a slick road or dirt and punch it the whole rear end of the truck wants to come around

This is totally correct, adding a posi-traction device to something that spins one tire so easily can just make it worse. At least with an open differential, you have one tire that is "rolling" on the pavemenmt, maintaining control of the rear. Both tires spinning can result in total loss of control.
Ease up on the throttle.

[riche]

could be worse... you could be driving a new truck with so much traction asist and torque management that the tires will not spin at all!!!!

[UltraBlue71]

Put a set of ladderbars on it! Or studded snow tires!

[71tahoe]

Originally Posted by UltraBlue71

Put a set of ladderbars on it! Or studded snow tires!

If it's a coil spring rear, he already has the equivalent of ladder bars. Studded snow tires will get less traction on wet pavement than what he has now but they leave really cool skid marks!!!

[69GMCLonghorn]

When I was in high school, I drove my dad's '69 C-20, with a mildly built 307 and SM465. My daily goal in the rain was to see how far I could A) light 'em up and B) pitch it sideways. Special note: B) is hard to do with a long bed and no posi, but I could do it! Now quit your whining and go ROAST 'EM!! HAHA

[big_al_71]

IF I floored my truck out of the hole it will burn my 295-40-20's for aty least two-three blocks now if I drive it like a human being I can drive it over snow and it will not spin it is all regulated by how my right foot presses the pedal and that is a fully built 406 with 438 hp at the wheels....

[allen123]

it has bfg radials
and on the rear end, does a open spin both sides sometimes? im just trying to figure what kind of rear end it is

[BLACK AND BLUE 67-72]

BFG Radials suck on wet pavement, mine has 275 60 15's and it will spin everytime it shifts, driving normally. You may have a limited slip rear end, it will spin both usually but sometimes it will spin only one. The easiest way to tell is pull the rear cover off and look at your carrier, if you can see all 4 spider gears then it is an open differential, if you see a clutch pack with 4 springs, then you have a limited slip.

[Ackattack]

I'm thinking you have a posi that is worn out and you have a heavy foot.

You foot will get lighter when you piss yourself after spinning it around in a place you don't want to.

[SCOTI]

Another factor are those 26.5" (short) tires. A bunch of these old trucks have 3.73 or 4.11 gears. Combine those ratios w/that short tire & it will want to spin pretty easy.

Maybe consider increasing the contact of rubber by going to a taller tire (275-60 BFG if you're wanting to stay in the same tire line).

[Seven Dub]

Get a taller tire. 50 series tire is not going to cut it. B.F.G. T/A Suck at anytime to heard of a compound. B.F.G. G-Force great tire and great grip.

[highperf4x4]

Originally Posted by SactoJim

Just pull a couple plug wires every time it rains.

Originally Posted by UltraBlue71

Put a set of ladderbars on it! Or studded snow tires!

studs? you trying to make life more exciting for him?

Originally Posted by allen123

it has bfg radials
and on the rear end, does a open spin both sides sometimes? im just trying to figure what kind of rear end it is

You can spin both in a straight line if you throw enough coals to it. Or you can make a limited slip spin just one.

You're going to give up wet traction for 2 reasons. A performance tire is designed for dry pavement. It's not meant to disperse water like an aqua tread or a highway tire. 2. You're tires are super wide so they are catching even more water. This promotes hydroplaning.