Hey guys,
I have a 2000 250 with the 5.4 and I'm running 20" XD's with 33" nitto mud graps and a 3.5" lift. The lift was on the truck when I got it and I've had the wheels and tires on for about a month and half. Last week I got in the truck and started down the road and right at 40mph it felt like the front end started to "bounce." It is now a constant thing and it happens exactly at 40mph. But as soon as I get up to abot 43 to 45 mph it stops. Again it starts at EXACTLY 40 mph every time and then stops once i speed on up. Anybody got any idea what could cause this?

ps I talked to the guy at our local truck shop and his suggested getting the wheels and tires "road armored?" Something about wheels and tires arent perfect circles so sometimes they have to be matched up. Never heard of it before so I figured Id throw it out to you guys and see what yall come up with. THanks.

 

Have you checked your shocks?

Get your tires and wheels balanced by a tire shop that can do a "road force balancing". Usually, this involves using a Hunter GSP9700 balancing machine. Hunter GSP9700 Wheel vibration Control System solves wheel vibration and tire pull problems that balancers and aligners can't fix