Tire Tread Life - Irrespective of Age

[Steve Ownby]

Originally Posted by Piker

Can I raise the pressure above 95 on this tire with an F load range? Says 95 psi max cold on the sidewall...

I was thinking maybe the RV should actually have G rated tires so I can go the extra 5 or 10 psi in the duals?

I have no idea what you mean by ride height? Are you thinking we have air suspension? We don't... Regular old shocks and springs... and hydraulic brakes. FYI... no exhaust brake either... really wish I had one... could really have used it in the mountains of Montana and Wyoming on our last trip.

Oh and thanks for the compliment... you are too kind...

-cheers

Hey Piker, I didn't realize you had the LR F tires. You are right, don't exceed the 95 max. When you replace I would go with the LR G. I'm guessing the tires are the most limiting thing on your weight rating. It's been so long since I followed your rebuild thread that I forgot you had a sprung suspension.

A guy with your skills could adapt an exhaust brake. You might have to downshift the transmission manually. They really are great.

[Piker]

So wait just a minute... if the chart I found on goodyear's website shows the max load at a given pressure... then where is the chart that shows the recommended pressure for a given load??

It looks like the recommended inflation spec on the manufacturers data plate of 80 psi front and 90 psi rear is way way off... especially with the 8R19.5's they call out. What in the world is that all about?

Kind of bummed... having the wrong load range tire is kind of an expensive mistake.

Someday Steve.... I do hope to have an exhaust brake adapted. I think I would just install a master on/off switch for it next to the allison control pad, and then wire in a relay for the exhaust brake to the switch on the brake pedal that turns the brake lights on. The brake pedal actually goes down a little ways to activate this switch before the linkage applies any pressure to the master cylinder. Seems like it would work slick. On our trip a few weeks ago, the steep and winding switchbacks over the Bighorn mountains and on beartooth pass were easy. Nit much traffic and I could go 10 or 15 mph if I needed... but I found that those long gradual 6% downhill grades on busy roads caused me the most issues with braking. I had to reduce the gearing so low in order to keep the brakes from getting scorched that my speed was ridiculously slow compared to the traffic around me. Normally I run slower than traffic anyways, but this was just silly. Once, just once... I ignored my gut and went to a gear higher... learned my lesson quick when the brakes got hot the very first curve I came to. An exhaust brake would certainly be an improvement. That said... there are probably 100 other things that need improved on this old rig first. Ok, so that was a bit off topic...

Cheers

[Steve Ownby]

Originally Posted by Piker

So wait just a minute... if the chart I found on goodyear's website shows the max load at a given pressure... then where is the chart that shows the recommended pressure for a given load??



It looks like the recommended inflation spec on the manufacturers data plate of 80 psi front and 90 psi rear is way way off... especially with the 8R19.5's they call out. What in the world is that all about?



Kind of bummed... having the wrong load range tire is kind of an expensive mistake.



Someday Steve.... I do hope to have an exhaust brake adapted. I think I would just install a master on/off switch for it next to the allison control pad, and then wire in a relay for the exhaust brake to the switch on the brake pedal that turns the brake lights on. The brake pedal actually goes down a little ways to activate this switch before the linkage applies any pressure to the master cylinder. Seems like it would work slick. On our trip a few weeks ago, the steep and winding switchbacks over the Bighorn mountains and on beartooth pass were easy. Nit much traffic and I could go 10 or 15 mph if I needed... but I found that those long gradual 6% downhill grades on busy roads caused me the most issues with braking. I had to reduce the gearing so low in order to keep the brakes from getting scorched that my speed was ridiculously slow compared to the traffic around me. Normally I run slower than traffic anyways, but this was just silly. Once, just once... I ignored my gut and went to a gear higher... learned my lesson quick when the brakes got hot the very first curve I came to. An exhaust brake would certainly be an improvement. That said... there are probably 100 other things that need improved on this old rig first. Ok, so that was a bit off topic...



Cheers

There are a couple of real tire experts who post on IRV2 who I have learned from about commercial tires. The manufacturers are silent about a recommended pressure and go with a minimum pressure. I generally take the pressure just above my actual weight and add 5 psi. We've been living full time in the same coach for 9 years so I'm comfortable that my weights are pretty stable. I think the pressure tables went through a pretty substantial revision several years ago but I'm not really sure what that was about.

I know your "to do" list is pretty long but I'm guessing that you will noodle out an exhaust brake before your next big western mountain trip. I've been over those Big Horn mountains & can't imagine doing it without my Jake. I'm about 47,000 pounds with my toad and the Jake made it easy.

Keep posting your projects, I enjoy reading about them.

Safe travels.

[Alan_Hepburn]

I've never had tires on our Class A wear out vs. age out, but when we had a fifth wheel we had an F450 as a tow vehicle and daily driver. It had 19.5" tires and we got close to 100K miles on the rear, and about 70K on the front tires. Unless the tires are run severely overloaded, or something is wrong with the chassis then the tires should give you well over 50K miles...

[Piker]

Originally Posted by Alan_Hepburn

I've never had tires on our Class A wear out vs. age out, but when we had a fifth wheel we had an F450 as a tow vehicle and daily driver. It had 19.5" tires and we got close to 100K miles on the rear, and about 70K on the front tires. Unless the tires are run severely overloaded, or something is wrong with the chassis then the tires should give you well over 50K miles...

The rear tires are definitely overloaded. I don't know what constitutes severely overloaded. I'm guessing when we are all loaded up the rear axle might have 1000 lbs more on it than what the tires are rated for? I can't say for sure until the next time we are loaded up...

I'm definitely not getting the wear out of the tires that others are experiencing... I don't really know why. Is an extra 1000lbs across 4 tires enough to do that?

-cheers

[Piker]

In an attempt to balance out some of the uneven wear, I went ahead and started pulling the duals off to rotate them. I was basically going to just switch sides while keeping them all spinning in the same direction. Outer duals would become the inner duals on the opposite side, and vice versa.

I neglected to consider one important thing though... doing this would orientate my valve stems backward since the inner duals have the long extensions and the outers are just stubs. The only way to put the tires in the positions they need to be in would be to break the tires down... probably not worth it...

I don't like wasting time, but I guess I needed to pull the wheels off to lube the slides on the calipers anyways...

In 4 years, the tires will be 8 years old. Even though I do all I can to keep the tires from aging too quickly... ie storing the RV in a pitch dark garage, and taking the weight off the tires when not in use... I'm concerned that 8 years will be pushing it on tires that have been overloaded. Besides... if the tires are half worn, I still have 20,000 miles left... I'd love to think I'd put those kind of miles on in the next 2 years, but that's probably not too likely. I seriously doubt we plan any more extended trips like the one we just took within the next 5 years... so I suppose it really doesn't matter anyways.

I'm still kind of in disbelief at the original tire specs given by the manufacturer... it just doesn't make sense... Unless tire load ratings have changed drastically since 1994, which I suppose is a distinct possibility. In that case, it's all on me...

-cheers

[Piker]

Originally Posted by Stevie3508

Piker, look at the rims. You said the original tires were 8R19.5, which call for a 6" wide rim, and you are now running 225 75 r19.5 tires that call for a 6.75" wide rim. Too narrow rims will cause the tires to wear unevenly.
Glad to see you have all of the big projects out of the way and are now worrying about the small stuff☺

Just wanted too follow up on this too... it looks like the 225-70R19.5's can be used on either a 6" or a 6.75" wide rim according to Goodyear's website... although it appears that a 6.75" wide rim is preferred.

Our rims are stamped on the sides - 6" wide.

Also, the minimum spacing on the duals for a 225/70R19.5 tire is 10". Ours measure exactly 10" and there is approximately 1.5" of space between the tires at their closest point.

-cheers

[Piker]

We took a short trip (1500 miles) earlier this fall up into New England, and on the way, I started to notice a wop-wop sound coming from the front tires. After we got home, I did a very close inspection and found that the front tires were chopped... quite a bit actually... The passenger side front tire was worn badly on the inside, but only on 1 section of the tire. The driver's side tire was worn on the outside, but again, only in one area. It's like the tires are not wearing round...

At this point, my goals are 3-fold:
1) Figure out what caused the uneven tire wear.
2) Correct the cause of the uneven wear so this doesn't happen again.
3) Do what i can to salvage what is left of the tires.

With regard to #1: I've checked the kingpins on both sides of the RV. They appear to be well within spec. The tie rod ends and steering linkage are all tight. The shocks are Bilsteins, and the passenger side shock appears to be good. (haven't checked the drivers side yet) I disconnected the top end and it immediately shot out and went to full extension. It was fun trying to get it collapsed and back onto the mount... I have not checked the bearings on the driver's side, but the passenger side bearings were a little loose... not terrible, but definitely looser than I would have liked them. I decided it was time to pull the hubs apart and inspect. Bearings and races were in good shape, but the grease was OLD. I cleaned everything up, repacked the bearings, and retorqued the spindle nut.

At this point I'm not seeing anything mechanical (at least on the passenger side) that would cause the severe wear that I'm seeing. I have not had the alignment checked yet, but I'm leaning towards the possibility that the wear is caused by the tires never having been balanced properly, or perhaps were out of round. We bought these tires on the way home from purchasing the motorhome 4 years ago... the tires that came on it were dry rotted, and we had a blow out before we got home. Rather than chance another blow out, we just had 6 tires put on right then and there. All I know is that the first part of the trip home with the old tires was smooth, and it drove straight as an arrow... as soon as we got the new tires, the vibration in the dash was very evident, and the rig pulled to one side pretty bad. I ended up swapping tires around after we got home and ended up improving the situation, but it was never quite right. Had I known then what I know now... I'd have gotten in touch with Goodyear and had this figured out... live and learn I guess.

At this point, I think I have to do some major rotating to try and salvage these as best I can. I'm starting with just the passenger side for now. Because of the valve stem configuration on the duals, I'm probably going to have to have the tires broken down and remounted where they will wear the best. I was told the tires would be bead balanced by the tire garage, so this will be a good chance to see if they actually were...

I'd like some input on what you guys think would be a good rotation. Below is a quick drawing of the tires, with some measurements that I took tonight of tread depth. The tread depth was measured in 4 places relative to the valve stem... and written directly underneath the respective representation of each tire. From what I can see, the inner dual has the most even wear of all the tires. I can verify this visually as well as with the measurements. I'd guess I should just swap the inner dual with the front and call it good? I don't know what else to think. Any suggestions?

I wish I had caught this issue earlier... but I didn't. I certainly have made some expensive mistakes with this old wagon... Nothing i can do now except try to move forward...

-cheers

[Reedster537]

Hey I have the same Goodyear tires with 22000 miles no wear. Proper inflation is important. The tire says to inflate to 120 lbs I have mine all at 110 lbs that's what les schwab said to go at. You wanted facts 36 ft. Thor 22000 pounds no toad g670 tires no rotation. Hope that helps

[Piker]

Thanks Reedster... looks like you have the G load range tires based on your inflation specs? The tag on our RV stated F load range tires, which is what we put on it... but based on the results from my trip to the scales, they don't have enough load carrying capacity when we're fully loaded. I know that this is one of the problems... overloaded tires, at least on the duals...

I also suspect the tires did not have enough balance beads added to them when they were put on... and/or the tires were out of round. Nothing i can do about it now... rotate and get what I can out of them.

-cheers

[Woodchopper]

Originally Posted by Piker

We took a short trip (1500 miles) earlier this fall up into New England, and on the way, I started to notice a wop-wop sound coming from the front tires. After we got home, I did a very close inspection and found that the front tires were chopped... quite a bit actually... The passenger side front tire was worn badly on the inside, but only on 1 section of the tire. The driver's side tire was worn on the outside, but again, only in one area. It's like the tires are not wearing round...
At this point, my goals are 3-fold:
1) Figure out what caused the uneven tire wear.
2) Correct the cause of the uneven wear so this doesn't happen again.
3) Do what i can to salvage what is left of the tires.

Piker
If there is enough tread left some tire shops can true/shave your cupped/worn tires.
Google "tire-shaving - where/who does it?" or "tire shaving near me".

[Piker]

Originally Posted by Woodchopper

Piker
If there is enough tread left some tire shops can true/shave your cupped/worn tires.
Google "tire-shaving - where/who does it?" or "tire shaving near me".

Thanks woodchopper... I'll have to look into that.

I took the tires off the driver's side this weekend... they are in about same condition as the passenger side regarding the lopsided wear. It's weird because there doesn't seem to be any rhyme or reason to it. The front tire on the driver's side is worn lopsided on the outside, while the passenger side front has a flat spot on the inside. The duals all have lopsided wear that doesn't seem to follow any pattern too. This must be a balance or out of round issue... maybe all the rims are bent, but I doubt it... the original tires were michellins, and smooth as silk running down highway.

The king pins all look good... I still have to check the shock on the driver's side front. The bearings on the drivers side are about the same as the passenger side... a tiny bit more loose than I would have liked, but not bad. Grease was old... and the seal was leaking.

Starting to wonder if I should just cut my losses and get a new set of steer tires... but dang... that's almost a grand... 4 years before I had planned on having to worry about tire expense. Bummer...

-cheers

[select55]

Originally Posted by Rich-n-Linda

I have just over 50,000 miles on a set of 22.5" Michelins. They just barely show any signs of wear.

The OP's tire mileage seems to be excessive. Too much wear in too few miles.

very hard to believe I had 44K miles on a 2002 ABDP 40 ft 255 22.5 and they had about 15% left on them

[Piker]

Originally Posted by select55

very hard to believe I had 44K miles on a 2002 ABDP 40 ft 255 22.5 and they had about 15% left on them

I don't know what to think... I have talked to some truck drivers who get over 100,000 out of a set of steer tires... And over 150,000 on the drive tires.

Probably altogether different...

I don't know what to think... Other than this is just a bummer...

Cheers