1970 Dart Manual Steering-Car jerks left and right when trying to drive straight...

67autocross said

I have a truck that I have run with 295 tires on 20 inch rims and 295 tires on 15 inch rims on all four corners, on the 20 inch low profile tires the truck jerks all over the place, put the 15"s back on and it stops doing it... And nothing is even close to out of spec on the front end. You would not risk taking your hand off the steering wheel on the 20"s.....that's my experience yours may differ.

Click to expand...

There's decades worth of Dodge Rams and diesel powered Ford trucks with "death wobbles" and steering geometry issues straight from the factory, all of them are "in spec". Maybe the big squishy sidewalls on the 295's for those 15" rims are masking your suspension or steering problem. Not to mention, how tall are those tires? I bet the 295's on 20" rims for your TRUCK have the same height sidewalls as most of the tires on 15" rims for these cars. But you didn't list the profile #'s so you're the only one that knows if you're making a fair comparison.

Sure, tires with shorter sidewalls will tend transmit more road noise/feel. And wider tires will track more than narrower tires, generally speaking. But regardless, changing from 15" rims to 17" rims should not cause your steering to "violently jerk", which is how the OP is describing his problem. That's not tires.