Outside tire wear

[gmcbuffalo]

I was reading Roadpilot's post about his tire wear and got to thinking about mine. I have noticed that the very outside ring on the tread is wearing smooth on both front wheels. Does this mean I have the wheels toed in too much or some alignment issue. Over the phone with Les Schwab they were talking low pressure but that should give me wear on both outer edges of each tire, not just the one nearest the skin of the bus. I have 7 year old Toyo on the front with less then 15K miles.
GregM

[charlesebrownjr]

You most likely need a front end alignment. The camber or caster is probably out of adjustment but the other important note is you said your tires a 7 years old. Most everything I have been told is to not use the tires past 4 or 5 years for safety reasons. I under stand that even if they look good, change them out.

[Jon Wehrenberg]

Greg,

As you surmise it could be toe in, alignment, and even tire pressures although that is unlikely. The outer edge wear was a common issue with Michelins in the early 90's but the metric tires seem to have cured that problem so my guess is the issue is with your bus.

At 7 years of age those tires need close frequent inspection for sidewall cracking and for sure need to be run at the proper pressures.

[truk4u]

Greg,

If you have the same tires you had at OK City, some were cracked pretty bad. I don't remember the tire positions, but I do remember the sidewall cracks. Be careful, they could cause a lot of damage if they blow or worse. I'm not picking on you, I just remember some of the tire conditions I saw while we were dealing with the Code Reader. If you don't have any tire cracks, sorry, I got you mixed up with another bus.:p

[gmcbuffalo]

Tom
That was me, and they were on the tag axles. I have them on the list to change out before the next trip. The Drives were new last year and Fronts will be moved to the Tags with the new buys going to the Steers. Outside of the read wear the Toyos only smell funny.

[Jon Wehrenberg]

Greg,

If you have tires worn in an irregular pattern and you put them on the tag axle you may find they literally destroy themselves very quickly.

I had steer tires on our first bus that had the old style Michelin outer edge scallops and within 5000 miles on the tag they had worn spots down to the steel cords. A tire that comes apart on the tag axle has the potential to take out an air bag and or a brake chamber plus do some body damage. The tires were the 12X22.5. I have never seen outer edge wear on 315-80s.

[gmcbuffalo]

Jon
thanks for that info I had assumed the tag would be a safe place for older tires, hence the move from the front to the tag when I put on the new Toyos (315x80) on. My drive tires are 12R22.5 and they will stay there until I get new one for the drives, which will be back to 315's.

After new tires I will make a run to Eugene Or for a alignment and inspection by the folks that work on the Marathons and other big rigs.

thanks

Greg

[truk4u]

Greg,

Just curious why you would go to 315's instead of the 12R's?

[Jon Wehrenberg]

Good question. Greg, your bus should have dual aluminum wheels on the drive axle. When Prevost switched to 315 from the 12 they had to use a steel inner wheel due to clearance issues. I know 12.00 tires are getting hard to find and maybe they are out of production, but consider more direct replacements for the rolling diameter of the 12s without the width of the 315.

I think it was Truk that had to replace his aluminum inner drive wheels because the drives were rubbing on the skirt.

[truk4u]

On Jamie's bus, the previous owner removed the steel inside wheel and replaced with polished aluminum. The steel inner wheel is slightly smaller in width and by installing the wider aluminum wheel, it caused the outside tire to rub on the painted wheel well fenders under certain conditions.

Greg, you may find the availability of 12R's are as good as 315's and they will probably be a little cheaper.

[gmcbuffalo]

They are cheaper, I bought 4 OHTSU I think or some combo starting with O and ending U for like $370 each. So you think it is a good idea to go 12r's all around?

[Jon Wehrenberg]

If I had a coach that was delivered with 12's I would replace them with the same size. In that way I would never have to deal with clearance issues, problems associated with a change in rolling diameter and I would not be adding to the unsprung weight which affects both handling and ride. You will have a hard time finding 315s for that price.

[gmcbuffalo]

Jon
The build sheet on my bus say it original came with 315. I changed to 12R on the drives because of the price and very little difference in size outside of width.