Odd Tire Wear

[manholt]

Pop, did you look at DOT # on tires?  Your coach is a 2017, your DOT # could easily be a 2015 or 16.  I will assume you have IFS...as Joe said about mine & after having 8 new tires put on, I had alignment checked in Canada...caster was way off...now I drive a different coach !  9,000+ miles since June!

[tireman9]

I don't see where the actual fully loaded "4 corner" weight.

Some input from a Michelin contact I have is suggesting the possibility if incorrect inflation for the actual load.

 

Could you post your 4 corner weights and your cold inflation numbers.

[mypopslou]

Tireman, I do not have a 4 corner weight but I do have axle weight, front axle is 13,820 and rear axle is 23491 GVWR is 38,600. Cold pressure is at 105, although as they heat up my TPMS reads 122

Thanks for your help

[mypopslou]

TIreman, also when I had my rig weighed my Jeep was attached so the front was 13820, rear was 21880 and it read my Jeep at 5400. My Jeep only weighs 3789 so I added the difference to the rear axle. Not sure that is correct but could not find a 4 corner scale.

Please let me know your thoughts

[mypopslou]

Tireman, I was mistaken, my Jeep does weigh ose to 5400 so rear weighed at 21880, I had a wrangler which weighed 3789, Grand Cherokee weighs closer to 5400

[tireman9]

On 10/14/2019 at 9:42 AM, Mypopslou said:

Tireman, I do not have a 4 corner weight but I do have axle weight, front axle is 13,820 and rear axle is 23491 GVWR is 38,600. Cold pressure is at 105, although as they heat up my TPMS reads 122

Thanks for your help

With a weight 13,820# I suggest you assume a 47/53% load split as a perfect 50/50 is very unlikely So 53% gives 7,325# which gives 115 psi according to the tables. ( You always go up in inflation)

I also suggest a +10% on inflation but not exceed tire sidewall number so that means 120 psi cold.

 

You will not find a "4 corner" scale except at FMCA Int'l conventions and some other large RV events.  You can also contact RVSEF to check their schedule. You can also check with local sand & gravel companies, Concrete companies and some building supply companies.  Here is the work sheet you will need to calculate your own 4 corner weights

[mypopslou]

TIreman, thank you for this information, so do you think the unusual tire wear on my left front is caused by under-inflation? The ride is already really hard and as the tires heat up they read 122, if I inflate to maximum will the amount they increase when hot become an issue since the wheel max is 120 as well as tire max.

[wolfe10]

Two points:

I don't believe anyone is suggesting "inflating to the maximum" UNLESS (read that BIG UNLESS, and hopefully not the case) that is the PSI recommended by your tire manufacturer for your actual weights  (plus perhaps a 5% fudge factor for safety).

 

And, both tire and wheel PSI are for COLD PSI.  Both tire and wheel manufacturers know that PSI will increase with temperature rise.

[mypopslou]

Brett, Tireman is recommending I inflate to 120 which is the max based on the weights and his calculating a 53% 47% weight distribution on front axle weight of 13,820. Thank you for reassurance when the tires reach operating temperature, I always worry when I see the inflation pressure exceed 120 and if it increases by 10% to 15% I could see readings of 132 to 138, do you think that is still OK?

[manholt]

Yes!  

A highway patrol station can tell you where to get corner weight done.  

[rayin]

6 hours ago, Mypopslou said:

Brett, Tireman is recommending I inflate to 120 which is the max based on the weights and his calculating a 53% 47% weight distribution on front axle weight of 13,820. Thank you for reassurance when the tires reach operating temperature, I always worry when I see the inflation pressure exceed 120 and if it increases by 10% to 15% I could see readings of 132 to 138, do you think that is still OK?

Think back, no-one ever gave it a thought before TPMS's were invented. Sometimes technology simply overwhelms us .

[manholt]

RayIN, I will agree, but before TPMS, we also had a lot more front end blow out's due to over/under inflation for weight!  A two edge sword...

[rayin]

On 10/17/2019 at 9:05 PM, manholt said:

RayIN, I will agree, but before TPMS, we also had a lot more front end blow out's due to over/under inflation for weight!  A two edge sword...

I agree with that. According to the Tire and Rubber Assn, over 80% of all tire failures are the result of underinflation/overloading. I used to have a hot link to the data, however they locked their website and I do not wish to pay  them simply to provide a valid link to that data.

This NHTSA/DOT pdf is quite interesting-IMO: https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/811617, pages, 6-8 pertain to tires as the cause of crashes.

[ispjs]

I think you can get pretty close by just using your axle weights and going by the charts, or at least close enough not to be underinflated.  I certainly would not want to air to maximum psi and then add a little.  

[mypopslou]

I found a highly recommended Truck Frame and Alignment here in Florida and will make an appointment to have my coach evaluated including alignment on both front end and rear end. Once I am confident that my alignment is correct I will make decision on my front tires. I will also ask this mechanic his opinion and act accordingly. I thank everyone for their help and suggestions and will let you all know what then end result is and what decisions I make.

Hoping to get an appointment this week or next

Stay tuned

[mypopslou]

UPDATE: I finally had my alignment checked and it was off on the front curb side as well as the rear was a little off but not bad. Both axles have been corrected. I asked the alignment mechanic and his boss about the unusual wear on that drivers side front tire. They both told me they had never seen tire wear like that and I should take it to a Michelin dealer fro evaluation. Coach rides much better with everything aligned so I think I will take a couple of good pictures to a Michelin Dealer to get an opinion before I get the coach out again.

Bottom line is I think I am looking at buying 2 new tires and hoping with the alignment that it does not happen again. I am upset that my 2016 coach which I bought new has 2014 tires on it although they are week 46 of 14.

Once I have the tires evaluated I will give you one last update on this issue.

Yes, my coach does have front independent suspension

Thanks again for your help and suggestions

[mypopslou]

Final Update on this issue: Took close pictures to a Michelin Dealer and he knew the tire wear immediately, called it River Wear which usually happens when the tire is under inflated or over weight. I told him I ran 105 in them based on the Michelin Tire charts and he told me never pay attention to those charts. RV tires should always have between 115 and 120 in them or else you will get unusual wear. He said they would never allow a coach to leave their business with anything less.

He also told me if your tire temperature ever reaches 165 degrees the tire is ruined. The integrity of the tire is compromised at that temperature and even if it did not malfunction then it is only a matter of time before it does.

The good news is that he told me the tires still had a lot of tread and are safe. I inflated all my tires to 115 and will keep a close eye on them but this is one thing I can stop worrying about.

Thanks to everyone who offered help and suggestions with this issue.

[manholt]

Pop, that "expert" is pure nuts!!!  All summer, I had 115 in my front tires and 110 in the other 6...I was close to max weight.  7 weeks ago, after removing a bunch of stuff that we carried but didn't use, I had my coach weight again and per the chart, I now have 110 psi on steer tires & 100 on the other 6, rides smooth!  

Tread.  We do not go by tread, sidewalls will go long before the tread does...time to change is normally 6/7 years!  You should be looking at new tires in 2020, please get new front tires NOW!

Merry Christmas!