The vibration feels like a wheel hop/bounce, and it becomes most noticeable around 60mph, increasing in intensity with an increase in speed. It is exacerbated by any rhythmic imperfections in the road surface, such as ripples.
The way I see it, if I have new bearings and my alignment is correct, I should be able to do over a 100 mph easy, just as older dragsters do with the same type of front end, provided my wheels and tires are good, and there are no loose/worn suspension or steering components. That said, I’m only looking for 65 with no vibration…..and I will continue to drive it at 60, as usual.
So-
I jacked the truck up today and followed the procedure posted by flatblu4748 . I have a low spot on every tire. The worst one was on a front tire, and it was 0.10. A tenth of and inch! The rest were .065 to 0.070. This measurement was of a definite “low spot”, not really a radial runout.
I didn’t dismount the tires, so I could not properly check the rim lateral and radial runout from the inside of the rims, but I did run the dial indicator along the outside of the rims as best I could- lateral and radial deviations ran between 0.010 and 0.020 on the outside of the wheels, and this is after they were blasted an powder coated, so I think the wheels are probably okay. We’ll see after the new tires are mounted.
My tires are ruined due to the truck sitting for many months on them. My mistake. I tried all the tricks- slightly over inflating and taking 50-60 mile trips, etc… after over 1,200 miles of trying, I am giving up and buying new tires. With my 3.73 rear end and my T5 close ratio trans, I need a taller tire anyway- 1st gear is like a granny gear right now.
I’ve got 15x6 wheels and have ordered a set of Diamond Back Auburn Deluxe radials, size 820-15. They will be the perfect diameter (I was running 215/75/15 and they were not tall enough). About a tenth of an inch narrower in the tread than my 215’s , which is good. Perhaps it did not help that my 215’s are on a slightly narrow rim (6” width is limited to 205’s per most charts I have seen).
Anyway, in a couple of weeks I’ll post again after the new tires go on, with pics and a test drive on the highway.
BTW- those Auburn tires are NOT cheap! $279 a piece, but Summit Racing offers free shipping. I don’t like ordering anything from large companies, and would have preferred to order direct from DB, but I figured the shipping $$$$ all the way across the country would be prohibitive. And since this is an unplanned re-do, the expense is already depressing. The reviews on DB tires are almost all stellar, and I want to get it right this time. DB told me that they will not ship tires with a cure date over 2 years, and that presently, because the product moves quickly and they just got a container in October, my tires will have a much more recent cure date.
Last edited by Norcal Dave; 12/09/2023 1:55 PM.
