Community Forums

chris cross · 07-17-2005, 02:13 PM

I've got Toyo 120's with 20k miles and have been experiencing the outside edge cuping of the front tires. After reading every forum topic I could find about tires, I feel that I've got a little knowledge(dangerous). Using this newfound intelligence we are leaving Page Az. in two weeks for Albuquerque to have 6 Michelin XZA2 Energy 275-70-22.5 tires installed along with 6 Centramatic wheel units. From there we go to Deming for the install of a Steer Safe. I wish I could wait until fall for this trip but we plan to start with Homecoming in October and then cover the Olympic Peninsula.
By the power vested in me I hereby declare my search is over. Speak now, or forever hold your peace.
Just kidding, all comments will be most appreciated. (decision is almost final)
Thanks

chris cross · 07-17-2005, 02:13 PM

I've got Toyo 120's with 20k miles and have been experiencing the outside edge cuping of the front tires. After reading every forum topic I could find about tires, I feel that I've got a little knowledge(dangerous). Using this newfound intelligence we are leaving Page Az. in two weeks for Albuquerque to have 6 Michelin XZA2 Energy 275-70-22.5 tires installed along with 6 Centramatic wheel units. From there we go to Deming for the install of a Steer Safe. I wish I could wait until fall for this trip but we plan to start with Homecoming in October and then cover the Olympic Peninsula.
By the power vested in me I hereby declare my search is over. Speak now, or forever hold your peace.
Just kidding, all comments will be most appreciated. (decision is almost final)
Thanks

Dave Fernandez · 07-17-2005, 04:48 PM

Hello Chris:

The Toyo 120's cups like that because of their design not because they are a bad tire.

(Note: the federal government regulates truck tires)

I talk to a Toyo rep at Homecoming two years ago and was told that it was normal and not to worry. He even provided me with information from Toyo which indicated they were aware of the cupping and that it was normal.

I replaced my tires because of age not because of the cupping on the front tires.

If my tires had not had turned five years old they would still be on the Alpine. If you want, you should have the tires rotated and save yourself some money for right now and replace them when they turn five or six years old. The Toyo 120's are an all position tire and should give you a lot of miles.

I have spoken my peace or given my $0.02 what ever

Have a safe trip and enjoy Homecoming.

Dave

Danny Gayhart · 07-17-2005, 05:16 PM

Michelin tires are some of the best available. I think you are making a good choice, especially since you also included the Centramatic balancers. I installed Centramatics on mine and consider them one of the best investments I have made.

Safe travels and look me up at Homecoming.

Danny

Tom and Patty · 07-18-2005, 05:00 AM

You could never go wrong changing tires out for new unless you are downgrading. Michelin is a good choice. Everyone swears by Centramatics but I just balance mine.

The Toyo's are a good tire. The cupping,(river wear)is very common on a free rollong axle, like Dave F. says, just rotate them to the rear. I bought our coach a year ago and it had original Toyos's. I rotated the steer tires to the rear, ran 18K miles, and finally in this May replaced mine just because of age, six years. I can't see your tires so you must be the judge along with an expert. My attorney advised me to say that.

Danny, I enjoy my VMSpc. The HP and torque guages were a fun addition. I use it on the uphill grades. It helps to keep working the engine at 85% to 90% and not 100%.

Hope to meet everone at Homecoming. Our first one!

ggbanks · 07-18-2005, 05:21 AM

Chris, I was just curious why you chose the Michelin XZA2 tire rather then the XRV that they make for RV's. Check out this site:
http://www.michelinrvtires.com/michelinrvtires/productg....jsp?application=RV#

chris cross · 07-18-2005, 07:39 AM

Jeff & Linda:
As I tried to express in my post, this is all very new to me so if anything I say doesn't make sense, please let me know. I did use the Michelin site for some of my "knowledge?" The reason for my choice is the rim size and load range. The XRV, available in my rim size of 7.50 - 8.25, has a max load of 5202 @ 110 with a load range of G. The XZA2 in the same rim size has a max load far exceeding the max. load of my rim (7390)and a load range of J. To my way of thinking, this gives a bit of latitude. I'm aware that the max. GVWR of the coach is 33,000 lbs.(front 13m,20k rear) My weight is 12k front and 19,500 rear so I have to watch my diet.
What precipitated my decision was reading about front blowouts.
Two years ago my wife and I had a 24' Artic Fox trailer towed by a 2003 Excursion diesel. Traveling from Page to Phoenix, we had a blowout of our left front truck tire. When the rim hit the asphalt the entire rig turned left across all lanes of traffic and straight into the desert. How lucky were we? There was a gap in traffic and it was one of the few places where there was not a BIG dropoff. The truck turned on its side and both units were completely totaled. The tires were Firestone. When we bought the truck we were aware of the recall and were assured that these specific tires were not on the recall list. Neither of us was hurt but we will go to great lengths to avoid another blowout.
Which leads me to our install of Steer-Safe. Does anyone have one?
Thanks

EngineerMike · 07-18-2005, 08:09 AM

Chris,
Your calculus for tire load looks like you are erring on the side of caution, which IMO is smart money. I weigh each axle, divide by two or four to get tire load (averaged), then add 20% for unbalanced loading and turns. Unbalanced load may be around 1000# rear over two tires, 500 front/tire. Some weigh each axle, which is better for the moment, but if you shift your stuff around you need to re-weigh. The real off-balance impact IMO comes from centrifugal force in turns, which has to be estimated in any case.
In your case, that'd be 12k/2= 6000# /front tire. +20% adds 1200# for 7200# rating min. 7390 rating looks like a good load match.

chris cross · 07-18-2005, 08:27 AM

Engineer Mike:
I'm sure glad I asked!!! I'm printing out your post so I can study it. What is IMO?
Thanks

EngineerMike · 07-18-2005, 09:22 AM

In My Opinion, i.e. FWIW (For What Its Worth; my lawyer told me to say that).
The big variable of imputed load shift from centrifugal force is a swag*, which of course goes stratospheric during a blow-out. I don't think you can correct for that in tire selection. So recognition of CF in some approximation should make for a reasonable selection criteria (IMHO**).
Mike
*Scientific Wild A$$ Guess
**Humble

Cedar41 · 07-18-2005, 10:19 AM

We have Steer Safe. We have not had a blow out but it really is great for keeping you straight when you are in high winds and when you pass or are coming on a large truck with a lot of wind drift pushing you.

It also make turns easy as it recovers like a sports car.

Tom and Patty · 07-18-2005, 11:08 AM

Chris,

QUOTE] The XZA2 in the same rim size has a max load far exceeding the max. load of my rim (7390)and a load range of J. [/QUOTE]

The tire size of 275/70R22.5 is too small for the Alpine. It is 2 inches smaller in diameter and turns 30 more revs per mile than what should be the stock tire...a 295/75R22.5. You can carry the weight OK but you will have to have a higher air pressure than a stock G or H load range tire just to carry the SAME weight. The tire is smaller the air envelope is smaller so you have to have more pressure. Width is the smaller also by 20mm. about 3\4 of an inch.

If you want to reduce the size by 5%-6% keep in mind you will be effectively changing your rear end ratio by that amount too. More RPM at a "true" 60 mph.

IMO if the tires on your coach are 295/75R22.5 keep to the same size with a load range of "H" which will carry single 6610 @ 120.
The 275/70R22.5 will only carry 6510@ 120psi. Max load at 6940@130 psi according to Michelin.

If I am wrong on your original tire size, ignore all the above except that "The smaller the tire the more psi needed to carry the same weight." Load range doesn't matter, it just allows higher psi, therefore more weight capacity. The higher the psi the harsher the ride ect..

If I have this wrong please let me know.

Thank you

chris cross · 07-18-2005, 01:22 PM

NO NEW TIRES:
A Toyo dealer in Albuquerque and a service rep for Michelin both said there is a nationwide backlog for the tires I wanted. (Tom & Patty-originals are Toyo 120z R11/22.5.) So I'm going to rotate, install Centramatics and Steer Safe and go to Washington. My tires have 20m and were made in '03 so I feel ok to go.
Cedar 41--Did you have your Steer Safe installed in Deming, NM.? Thanks

SteveS · 07-18-2005, 04:03 PM

Chris - Did you read the post by Pat (AlpineAZ) and his tire blow-out? He had a very hard time keeping the coach under control in the turn. Under the situation he described it seems to me that a Steer Safe would hinder gaining control of the coach. I thought the springs in Steer Safe tend to force the wheels straight ahead...making it harder to turn. If so, this would only exascerbate the situation and make it harder to gain control. Best of luck whatever your decision may be.