Tire question

[George Doogle]

I've got a question about tire performance on my '01 4x2. I'll try to make it short but it takes some explaining. Within the last year I replaced the upper and lower ball joints, front and rear shocks, bearings, rotors, brake pads and one spindle after I damaged the threads. All this was followed by a new set of Uniroyal Laredo's and an alignment.



Initially I felt the ride improved over the worn out tires that were replaced. However, the tires did not ride as well as I was hoping but figured it was never going to ride smooth like the wife's minivan. After the first rotate and balance I noticed a rythmic bounce from the rear end when riding at a constant 49mph and again around 65mph when running on a smooth road. Over the next weeks I went back to the shop four times about it. The first three revisits they rebalanced the tires, did a 'road force' balance, and spun one tire on the rim before rebalancing all four. On the fourth visit the shop foreman road with me and said it was bad tire. Great I thought! When I picked it up they said they 'measured' all four tires and 'replaced the worst one'. They said the tread was 'running in and out' and that was what I was feeling. The 'bounce' improved alot but I can still feel it get into a rythm just under 50mph and again at 65mph.



Is there anything, other than tires, that could cause what I describe as a 'rythmic bounce' when driving at certain speeds? 49 and 65 seem to be my magic speeds. I'm no truck tire expert and I've purchased multiple sets of tires from these guys over the years, so I'd like to know if there's any other possible reason for feeling this. In all the return visits to the shop they've never said there was anything else wrong with the Trac. I'm trying to decide if it's easier to take a loss and replace the tires at my expense (from a completely different retailer) or keep going back to the place I bought the Uniroyals to see if I can get somewhere.



Thanks for any advice!



george

 

[Jerry Gerner 2]

One or more of the tires could be out-of -round, which means that there is just no balancing them perfectly. Some shops will just get it within 1/4-3/4oz. and say it's balanced but certain tires you can tell if their balanced or not.



ALso check the wheels and axle to see if their bent at all, that will cause it to feel out of balance too.



Jack up the rear of the truck (block the front tires front/rear put jack stands under the frame or axle) start the truck up and put it into drive, just let the wheels turn slowly as it's usuaslly easier to see at a slow pace, have someone otu back look at the wheels and see if they can see any wobbling, etc. (always have someone in the drivers seat incase truck happens to come off jackstands, never had it happen but for safety I suggest doing so).



While doing the above check yopu can take something hold it just above the tread while tire is turning and if thetread hits the object then you have an out-of-round tire.

 

[Scott Tanner]

If you still have factory shocks, then that's your issue..

 

[George Doogle]

I found I had 50 miles left on a front end alignment warranty at a different shop and decided to have take a look at the front end. They said the tires were balanced perfectly but the right side alignment was out. I have had chance to see if what change it makes. However, they said the bounce at 45 in the rear end sounds like the overdrive sticking or perhaps the ujoints going bad or the drive shaft is out of balance. Since the problem doesn't happen at all speeds and the bounce goes away when you accelerate it sounded to them like a drive train issue. They said the ujoints had a little play but not enough to cause an issue. Their advice was to have a real transmission shop or a drive train specialist have a look at it.



When does the overdrive kick in? Is it possible for it to cause the type of bouncing that I'm feeling from the back end when riding on a smooth road at a steady 50mph



Does an out of balance drive shaft cause roughness at certain speeds and could anyone explain how it feels?



Personally I was really impresssed that the shop offered up some ideas, other than tires, that the first shop had never done. On top of that, they didn't pretend to be capable of doing the work and didn't charge me for the time they spent looking at it. Maybe I'm easy to impress.



George