When I bought the car it had bias ply tires and cornered like a cat. Since I put radials on it it corners like a sick pig - oversteering badly. Do most people put sway bars on in this kind of situation? Someone suggested changing castor and/or camber, but I don't recall any details. Good idea? Bad idea?

Ross,

Usually, going to radials makes handling better, so there must be something else going on. Are the new tires a much different diameter/width, or are the wheels different? You need to run at least 32psi cold in radials, and I usually run 34. Bias ply tires use much less air. Ignore the stickers on the car for pressure ratings since they are for bias plys. Better shocks will also help a lot - like the KYB Gas-a-just.

Lou

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Home of Slant6-powered fun machines since 1988

What kind and size of tires and rims are you running?
Did you put radials all around? Mixing radials and bias ply tires can lead to interesting handling.
You may have just upgraded the tires enough to bring up the next weakest link.

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"When you find a big kettle of crazy, it's best not to stir it." - Pointy-haired Boss

1964 Valiant V200, 225/Pushbutton 904
BBD, CAI, HEI, LBP, AC, AM/FM/USB, EIEIO

As close as I could get them. I think I used 34.

I may have described the difference poorly. The turn with the bias ply tires was flatter, but not "stickier." I'd agree the radials should stick better. But wouldn't it make sense that greater traction would give a greater sense of oversteer in a hard turn? (I've never held it in a turn to see what would happen if I didn't back off the turn.) It doesn't feel like its sliding. It feels like it turns a tad late because of the softness then wants grab suddenly and roll over.

I guess the cat analogy came from life experience. I saw a cat charging through the house and trying to turn a corner on a freshly waxed floor. He wasn't turning much, and his "wheels" were spinning, but he stayed straight up. (That was in the early '60's so I assume he was running bias ply.)
Food for thought. Thanks

Hmmmmmm.

Uniroyal Tiger Paws. Original 13 inch rims. Something just now occurs to me. Maybe the 185's shouldn't be too huge a problem, but maybe the 80 width is too much for the original rims? Maybe just too much blubber on those wheels? But I think I started out with 60 width. (Maybe there was no such thing as 60 width. That was a long time ago.) Thanks.

Radial tires allow more sidewall flex and the sidewalls are decoupled from the tread; that is, they flex and move more or less independently, that's how they keep the contact patch on the road. The difference can be disconcerting when you first switch. The better new designs have sidewall stabilizers in them to reduce side sway but the lower end products may not have them. Lower profile tires are also stiffer in the sidewalls but the 80 series profile is pretty tall and will wobble a bit.

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David Kight
'62 Valiant Signet, White
'98 Dodge Dakota
'06 Jeep Liberty

Growing older is unavoidable but growing up is strictly optional.

I guess I'll probably be putting 14" wheels somewhere on my priority list. They would be wider, right? I don't know where you find that kind of info. Thanks.

More grip means more body roll. On an A-body, body roll reduces traction more at the front than at the rear. The rear axle stays perpendicular to the road, but an independant front suspension doesn't keep the tires as perpendicular. So there is less traction up front, and that causes more understeer. Mopar's engineers did not expect a stock A-body to wear tires as sticky as some of the modern street rubber out there. Your best bet may be to reduce body roll using anti-roll bars and/or stiffer springs.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

First let's go over how to read the #'s on the side of a tire. Let's go with a 185-80-13. The 185 is the section width in MM, it is 185 mm wide. The 80 is the aspect ratio, This is the side-wall height in relation to the width of the tire in percentage. So the side-wall is 80% of the tire width. And the 13 is the rim diameter. With that much side-wall and the fact that the tiger paws have a soft side-wall for ride and comfort they aren't going to corner all that well. To get the car to grab better you need to get a tire with a shorter and stiffer side-wall. That tire is 24.7" tall with a side-wall that is 5.85" tall, to get a tire that is the same height with a shorter side-wall you need to increase your with and decrease you aspect ratio. A 205-60-15 is still the same height, but has a section width that is 20mm wider and a side-wall that is 4.85" tall which will give you much better handling and still ride nice and comfortable.

As for radial tires they give you a better ride and track better then bias-ply tires. This is how they go over bumps and grooves in the road. Bias-ply grab the wear grooves in the road and make lane changes a bit jerky, radails don't. Radials also hold their shape better for better stability.

The 185 80 13 tire is correct for the 13x4.5" rim.

What you describe sounds more like understeer than oversteer. With oversteer you'd be tail happy and want to slide out. As for the flat cornering with bias plys, it's because they had less grip. With the radials, they're gripping better, and the car rolls over.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

As for 14" tires, you can use either a 195/70 or 205 /70 on a 14 x 5.5" rim. And if you have the small bolt pattern, a 14" rim is about it.


I'm running with 195/70 14's on the 14 x 5.5" rim with F/R anti-roll bars, and KYB's. The handling is great.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Definitely one of the options I have in mind. thanks.

So 60, 70, 80, etc. are hight instead of width. Thanks.

I've never seemed to get that right. Every time I think I have it, I have it wrong.

With the radials the turn rate seems to increase, whatever you call that. Thanks

The 14s are 5.5". The 13 inchers are narrower, right? I could definitely use some handling improvement. Other than that, I think I need to either increase my tire diameter or get overdrive, considering where gas prices are going. All this time I thought I might be able to take a trip soon??? Thanks.