Well, After 2000 miles on a new set of Bridgestone tires in the rear of my Barth, all I can say is THESE THINGS ARE COMING OFF AND MICHELINS ARE GOING BACK ON!!!

I had Michelins on with a few thousane miles left but as I was taking some others along, I didn't want to run the risk of tire trouble along the way, this trip was supposted to be about 4000+ miles.

Changed out the Michelins and was talked into Bridgestones by the tire guy, we compared the side wall difference, Bridgestones are stiffer and the rolling radius, slightly bigger, and his statement that he put the same size on his SOB and loved them, was convincing. Drove home on city streets and packed for the trip. Headed out very earliy the next morning and all I can say is WOW, the rear was like it was on marbles! Sure the Breakaway is a little tail happy but this thing is a hand full now. This is about as close to a back to back comparison as you can get, nothing else was changed, Tanks were full before and after.

Even thou the rolling radius of the Bridgestones is listed as larger then the Michelins, and was much larger then the worn Michelins that I took off, there was NO change in the MPH comparison between the speedometer and the GPS, go figger?!

Our trip has now been shortened partly due to high temperatures in the Southwest and some other issues have come up. Can't wait to get back get these things off! I sure wish that the rolling radius of the 225R70 19.5 would be bigger, but will just going back to the 8R19.5 on the rear, don't know what I will do on the front yet! Might switch out to Goodyear G670 225R70 19.5.

Bridgestones are stiffer...

If they are stiffer, you may be getting the SAME EFFECT as mixing non-radials with radials: horrible -read: frightening!- handling! (I speak from an automobile experience) Will the tire guy allow you to "test drive" two new Bridgestones on the front to see if this cures the problem?

OR: (unlikely) Possibly the rear tires' air pressure is too low??
2) Rule of thumb: Don't mix brands.

Did you have them balanced?

What tires are on the front?

What load range are the Bridgestones?

I have the Bridgestone R187s (8.00x19.5) on the back, and handling is very good.

Bridgestone all around after Michelins, ride is as good if not better on 28' Regal P30 454 JKB

Fronts are Bridgestone, tire pressure is 100 lbs (I always check each mornig before heading out)

load range F 12 ply, Bridgestone R187

Rusty, I think I have a greater over hang then you and for sure have a huge weight difference with the Cummins and Allison 6 speed, any tire differece or chassis change will have a greater effect on handling!

Will be seeing a top notch chassis guy tomorrow here in Las Vegas to help get this sorted out, but like I said, this was a back-to-back comparison, with very little change in loading. I have already checked the lateral bar and joints from the top of the diff to the frame and they are fine!

Have you had your Barth weighed? Both front and rear axle? What pressure are you running in the rear? 100# seems very high for the front. If you were running Goodyears on the front, the weight on the front axle would have to be 7430# to merit 100# Rear would have to be close to 14000# to merit 100#. A lot of these tire guys just pump the things up to their max. They're nuts.

Bridgestones are rated at 3305 @ 110 psi for dual use, which is very close to the axle limit of 13.5K lbs. I do run the fronts at 95, anything less, I get side tread wear (even on both sides) rear at 100 lbs. Anyhing less then 100 lbs on the rear with the Michelins would increase the rear movement.

The Alcoa wheels are also rated at 110 psi, and yes I do not run things at the max if at all possible, shouyld have the weight today as part of the investigation.

Ed, we both have the same length overhang, but you're right; I'd bet you have another 4-500 lbs. back there compared to the 6.5L TD and 4L80E. Rear axles are the same.

I don't know why your tire guy put on 225R70 19.5s instead of the R187 8.0R19.5s, but mine tracks like it's on rails.

I run the Bridgestones at 100 psi rear (10,650 lbs.), 95 psi front (5,260 lbs.)

BTW, since the inflation chart is dang near impossible to find, the link is http://www.bridgestonetrucktires.com/us_eng/load/index.asp

I have R187 on the rear! but I do have 225R70 19.5 on the front.

The trouble didn't start with the 2225R70s on the front (I put those on right after buying the Barth) It really started when I changed out the Michelins for the Bridgestones just before this trip.

Many guys with the 19.5 wheels are indeed putting 225R70 on the front because you have a lot more meat on the road.

I was thinking about 225R70 for the rear but they are shorter by an inch or so and I would give up 75 RPM at cruse, not good for mileage. I don't think the Alcoas are wide enough for dual 225R70 anyway.

I misunderstood...anyway, I have Kelly 8R19.5s in the front...

I wonder if you have an alignment issue or bad spring bushings (I noticed the exterior flanges on mine are splitting - the cores seem to be holding up - so I ordered and received a new kit from Spartan)?

quote:

Originally posted by Gunner:
Will the tire guy allow you to "test drive" two new Bridgestones on the front to see if this cures the problem?

That would be the first thing I would try.

quote:

Originally posted by Rusty:
(I noticed the exterior flanges on mine are splitting - the cores seem to be holding up - so I ordered and received a new kit from Spartan)?

I have looked at this as well, could you give some contact info at Spartan?

Again guys lets not loose sight of the rfact that this extreme tail wagging did not exist with Bridgestone fronts (225R70)and Michelin rear. (8R19.5) Only when and immediately after changing to the Bridgestones did this condition exist. It must be something with the sidewall construction of the Bridgestones, I noticed that these have sidewall plie (1 steel) and tread plie (4 steel)stamped on the side of the tire. The 225R70 front have the same plie rating.

I don't have Michelins here for a comparison but that would be interesting.

I got email from AAUSER@spartanmotors.com, but this is more likely useful: info@spartanmotors.com

The phone is 800-543-4277; they need the VIN to identify your chassis. They're very helpful, friendly, and most of all, they do what they say they will.

I wonder if you got a set of R187s with a belt problem. Mine had R187s (several years old) on the rear, which I replaced right after ferrying it home, due to dryrot. I was open to suggestion, but my Tire Guy (whom I've known for over ten years) recommended the R187s after looking at those and alternatives (I really wanted a more aggressive tread, since some of the boondocking I do is, well, in the boondocks - and nowhere near paving).

But I think Bridgestone offers the 30-day test drive on the R187s as well as car and light truck tires.

BTW, I have Bridgestones (including Daytons on the 1-ton van, Bridgestones on the car, and the SOB sports Firestones) on everything.