Bear with me, maybe I answer my own question here. I bought 3 new Wrangler HPs with the raised white lettering. Why three? I figured I had 44k on the old ones and one tire was scupping-right front, so the nicest with about 10k of tread left becomes the spare. This way I put the brand new spare on the road with the three new tires. I get a vibration. 58-68 mph. Not above and not below, some macadam roads worse than others, but not above and not below 58-68 mph. I swear it's the tires. Dealer balances the tires 2 times, 3 times. Then he says you got a brake pedal vibration, I say yeah, but now before this, I put new rotors on the car. Same problem. Now, I been living with it for 14k miles, truck has 58k now. Left front tire scupping outside, So, I rotate the tires. Now, it is vibrating worse. Same speed 58-68mph. What? Could it be that fourth tire? The OEM blackwall Wrangler HP brand new spare that I put on? I don't know does the raised white walls on the new HPs mean a different tire structure or something? . Took it to get alignment yesterday Goodyear said minor toe in, hardly out. What do you think? Should I get a fourth tire then I got three with 14k on them. This vibration is through the floor mostly seems passenger right front to my foot on gas pedal feeling. Man it's annoying and I don't need to hear about this is not a luxoboat as I got a 3 Silverados at work that are smooth on any highway. Thanks in advance. Regards, MIKE

 

I was reading this thinking that it must be the tires untill you mentioned feeling it through the floor, have you considered wheel bearings as mine did the same thing at a particular speed and felt through the floor and pedal. Turns out they both had failed and were totally dry, the inner race was totally gone. Steel on steel.

 

My 2007 Ram 1500 w/ 20's has a brand new spare....unused.

I too thought about getting 3 new HP's and using the spare. I dropped the spare and it's got dents in the sidewall that scare me. Plus I don't like the HP's in cold, rain or snow, something I deal with here in upstate NY.

So maybe that you have some sidewall deforming like my spare does ? My spare is new, but the tire is from 2006/2007 and been squeezed against the frame rails for all this time. Good for a spare, bad for a full time tire at this point, imo.