Quest for a smooother ride....Or.... Tire Problems on Ford F-53 18,000 pound chassis.

Our 1999 Seabreeze 33 has never been the smoothest riding vehicle we've owned, but on the last trip it began to bother me severly, especially at speeds above 60 mph.  It seemed the rear end was out of balance, and "jumping" in time with tire rotation, to the extent I felt that something might eventually break.  This summer I heard about Equal tire balancing powder  (http://www.imiproducts.com/imi_htmlcode/imi_equa/imi_equa.html)   and found a tire dealer near me that recommended it strongly saying truckers loved it and would no longer use his $30K regular weight balancing machine.  We had it installed on all 6 tires, with the special screened shrader valve cores recommended, and I was impressed by the improvement.  The tire dealer also cautioned me to keep the tires at their 85 psi rated cold maximum pressure to avoid "scalloping", rather than lowering to 75 psi as I had been trying to do to cushion the ride (Does anyone know what scalloping is?).

After the Equal balancing, we took a short weekend trip, and I noticed the greatly improved ride, but also a "thump thump thump" from the left front tire that did not diminish as we drove.  I expected a few miles of thumping after sitting two months unused, but this stayed the whole trip.  It nagged at me, although I found nothing wrong when I looked, and although annoying, it did not seem to affect handling. After returning home I decided to change the OEM shocks for Bilsteins, not a bad thing to do on general principles after 42,000 miles, and ordered them online; perhaps a miracle will occur.  :-)  Later, when I was under the vehicle changing oil, I noticed a strange appearing spot in the left front tire tread.  At first I thought it was a tread belt failure bulge, and immediately decided to practice changing a tire!  The changing went easily with the 12 ton bottle jack I have; the lug nuts came loose easily standing on the OEM lug wrench, despite dire warnings they are really hard to break loose without a "pipe" wrench extender.  The tire's appearance puzzled me, however;  the problem did NOT appear to be belt failure but uneven "flatspotting" on both edges of the tire in one place on the circumference of the tread. The tires are all OEM equipped Goodyear G159 245/70R19.5 light truck tires.   

The rest of the tread around the tire was totally normal.  The tread at each edge on the flat spot appears worn flatter than in the center.

It is apparent that some flattening is also taking place a bit to the left of the flattest spot above the chalk arrow, with a high spot in between.

This is another view, showing the normal tread on each side of the flatspot(s) area. Does anyone have any idea what might be the cause of this problem?  This tire was changed for the spare, which was equal balanced before mounting.  No vibration problems or thumping at all were apparent after the replacement.  If anyone has ideas or comments on the cause, or cure for this problem please email me at  buzzy dot bee at netzero dot net   making the "dots" and "at" be the appropriate symbols, with no spaces. ( I am only online weekends, and miss many posts to usenet, so please do email also).  I am wondering if this is the "scalloping" phenomenon my dealer was warning about?  Can the tire be "scraped" round again, and if so by what type of shop?   I am now running 85 psi in my tires, and the 1100 miles of the trip we've made from MA to the Mississippi river has been the smoothest riding ever in this motorhome.....but MORE follows.

I originally intended to install my Bilstein shocks myself, but realized the error in my plans when it became apparent that (1) I needed a compression tool to install them (which I could rent locally for $18 a day) and (2) I could not get the 3/4 inch bolts to budge even when I used penetrant on them for a week and jacked an 18" breaker bar to the full extent of the room available under the chassis (bending it significantly).  The shocks had a prominent warning "DO NOT HEAT".  This was clearly a job for an air impact wrench.  The air setup cost $54 to rent for a day.  Camping world would install my shocks for $18 each.  We made an appointment in their Bolingbrook IL shop at a time that we thought we would be there.  They had the job done before I finished shopping their store, and the charge was just as advertised; no extras, no tax.  I went under the rig after the job and found all was as good as if I'd done it myself....maybe better!  They even kept the door closed to prevent our cat from escaping.  I'm happy with Camping World  and will use them again when I get in over my head.  :-)

I was very impressed with the improvement the new shocks made; the end result is a PLEASINGLY smooth ride, so much so that I had to warn my wife of the 75 mph speed rating on our tires.  :-)  The concrete highway panel cracks do not get thru the new shocks at all, and we get one thump for large bumps, not the several shaking oscillations the old ones gave us.  There is noticeably less sway in turns and the handling seems more "surefooted".  The F-53 chassis may deserve its rough ride reputation as it ships from the factory, but it cost me just $140 for equal balance in 7 tires, $325 for the shocks and $72 to install them to change the whole feel of the drive in this vehicle; that seems like one of the best $537 I have spent on the motorhome so far.  The rough ride on the F-53 CAN be fixed!  :-))

HTH someone else...

Barrie B