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Automobilist · 06-08-2011, 10:46 PM

Interesting stuff... I removed the TSTT tire pressure monitoring system, reset all tire pressures, and they actually remained the same for 24 hours. The previous issue stemmed from low tire pressure, WITH the TSTT system installed. When I checked the system this afternoon, it showed one wheel sensor at 80 psi, (which I had set the day before to 101 psi) I removed the TSTT sensor, and my manual gauge still showed 101 psi. In fact, two TSTT sensors didn't register at all, but when removed the tire showed exactly the pressure I had inflated them to yesterday. In other wordsw, it appears when the TSTT sensors were attached, tires either lost pressure, or falsely indicated low pressure. The manual tire pressure gauge doesn't lie. (much) (I use a highly accurate race tire pressure gauge) I'm really wondering why the TSTT sensors would leak down, and / or erroneously report incorrect pressures? The only common factor is I had to use valve stem extenders on all tires, perhaps they caused the leakage?

Tomorrow I'll take a good long drive and get the four corners weighed. Don't know if I'll ever really trust the TSTT system though...

96 Wideglide · 06-08-2011, 11:01 PM

Quote:

Originally Posted by fxdave

my toyos did that for the first 800 miles or so

I'm concidering moving the steer wheels with Toyo's to the tag axle, and moving the Michelin XZE tag wheels, up front!

Piledrive · 06-08-2011, 11:25 PM

I just put 6 new Toyo's on our 37G Adventurer in April and will be very interested in what others have to say here. New to us MH had 24000 mi and 10 year old GY's on it. haven't yet gone anywhere but will be headed for MO. later this summer.
It seemed to track great on the 10 Fwy from Rialto to our place near Redlands CA.

AZgl1500 · 06-09-2011, 12:18 AM

First thing I would do is rule out improper toe-in.

If they are toed-out the slightest bit, you will play the devil keeping it on the road.

jack it up, put support under the suspension, just enough to clear the tires.

Now spin the tires and have a sharp pick/nail/scribe, etc.... Make sure this sharp tool is fastened so it can't move laterally.

Spinning the tire, push against the tire and leave a scribe mark in the tread. Do the same on both tires.

Set yourself up on the back side of the tires.
Now, using a tape measure, have an assistant hold the loose end of the tape at the 1" mark exactly in the center of that scribe mark. Now you look to see where that mark is on the other tire. 98" ??

Move to the opposite side of the tires and do the same measurement. If your theoretical measurement the first time (on the back side of the tires) was that number 98.0 inches, then the measurement on front side of the tires needs to be slightly less. Something around 3/16" inch for big tires. 1/8" for 15 inch tires like on my dually pickup.

costs you nothing, lets you sleep by ruling out toe-out. pun intended.

bbeane · 06-09-2011, 04:58 AM

I would willing to bet your problem is alignment and tire pressure not the tires themselves provided they are the proper load rang. As others have suggested over/under inflation will cause issues with wandering. Check Toyo's web site for proper inflation pressures. As to the alignment thats the only mechanical thing that was messed with, sounds like possable castor issues. I would have the shop recheck the alignment, computer alignment is the best thing since sliced bread. However one error on the setup makes the whole alignment wrong it's easy to do. Also when you have your coach aligned it needs to have the "normal load you travel with" 1/2 tank of fuel, water tank full/empty? as these could add up to 1000 lbs+ or more, do you pull a heavy trailer, all of these things affect alignment?

wa8yxm · 06-09-2011, 09:58 AM

Well.. I have had the shop mess up the alignment on a car, (Much more expierence with cars than motor homes in this area) So I'd say "Possible"

I also wonder about tire pressure. .if the pressure is too low the sidewalls may overly flex and give you the SENSATION of sideways movement which you then correct causing.

Well, it takes a while to damp down.

However over pressure is no good either, as it reduces control.

Scale the beast (each corner) and put the wheels to the recommended pressure.
(Recommended by the manufacturer of the tire based on weight NOT by the maker of the motor home)

Long Island Mac · 06-09-2011, 10:17 AM

Had same problem with an 05 38'. Had unit checked at a Spartan dealer. Front alignment was set at "0" for both front tires. This will give the wandering. had reset at +3.5, and problem gone. Handles great now. Have put 17,000 since buying. Was great at start, but didn't realize the small changes as milage built up. Really noticed on way back from Florida (to Long Island) last March. Now in Colorado, love the handleing. Best of luck.

Gadget Man · 06-09-2011, 08:05 PM

I am having the EXACT same problem with a new set of Yokohama's. You can read my post here.

I also run a TPMS, but I have seen no issues with my pressures or temps. I had my coach aligned about 1200 miles ago and installed a Steer-Safe shortly thereafter. I had the coach weighed and per Yokohama's tire inflation chart, have the front axle tires inflated to 100psi and the rears at 95psi.

Craig

pyroman175 · 06-09-2011, 08:31 PM

I would almost guarantee it is the TOYOS, I had the exact same problem, but it was on my F250 with 35" tires. I had 35" Pro Comp tires on it and the day I put the Toyos on, I was all over the HWY. I tried everything , changing tire pressures, shock absorbers etc. The tire shop is owned by a buddy of mine and I told him I would never buy Toyos again. To top it off they were $400 a piece... anyways just my 2 cents :-0

Coached · 06-10-2011, 01:23 PM

First, and in the interest of fair disclosure, I think Michelins are the only tire to use on a Motor home and am not much interested in hearing otherwise (this is our 5th class A) ... however, your problem started right after installing the tires, right? I agree that you should have the "before" and "after" numbers by the way; the alignment guy should have provided them. It is possible that you have belt separation or just a plain bad tire. Move the left front wheel and tire over to the right front and vice versa - any difference? If there is you probably have at least one bad tire.

Gadget Man · 06-11-2011, 06:52 AM

Quote:

Originally Posted by Tiff Inn

First, and in the interest of fair disclosure, I think Michelins are the only tire to use on a Motor home and am not much interested in hearing otherwise

Tell us how you really feel...

In my case, I re-checked the Yokohama inflation chart, and I have the tire pressures a tad high. I can lower the front tires 10psi and the rears 5psi, and still be within the recommended pressure for the weight they are bearing. I'm hoping this will cure my over-steer issue. I also just ordered the Super Steer Bell Crank, in case it's more than just the tires. This is an upgrade that I've been considering for a while anyway.

Craig

Automobilist · 06-11-2011, 04:13 PM

Weighed the coach:
Left front: 4400
Right front: 3480
Left rear: 7780
Right rear: 7940

Gross weight: 23,600 lb.

As indicated, Toyo recommended pressures are:
Left front: 100
Right front: 75
Left rear: 85
Right rear: 90

Mike Canter · 06-11-2011, 04:20 PM

All the tires on the same axle MUST be at the same pressure. So in your case you would run your front tires at 100 psi and your rear tires at 90 psi. It is also highly recommended to increase the pressures by 5% for safety so 105 on the front and 95 on the rears.

Just as a warning there are a few individuals who believe that you should run different pressures on tires on the same axle based on the actual weights. All the tire company say NOT to do that because it will make for unusual and dangerous handling.

Elkhartjim · 06-11-2011, 04:54 PM

Quote:

Originally Posted by Mike Canter

All the tires on the same axle MUST be at the same pressure. So in your case you would run your front tires at 100 psi and your rear tires at 90 psi. It is also highly recommended to increase the pressures by 5% for safety so 105 on the front and 95 on the rears.

Just as a warning there are a few individuals who believe that you should run different pressures on tires on the same axle based on the actual weights. All the tire company say NOT to do that because it will make for unusual and dangerous handling.

Exactly!