Tire Pressure - 50psi?

[technomadia]

When we had our wheel bearings repacked recently, the technician pointed out that he thought it was very unusual that the outside edge of our curb-side tire was going bald.  He thought it might be an issue with axel alignment?!?!  He swapped the left and right tires to even out the wear, but in the few weeks since it looks like the new curb-side tire is starting to wear the same way.

 

We just met Jim Oliver in Lake Havasu, and I asked him about it...  He said he has seen this uneven wear before on one of his trailers, but he was not sure what might cause it.  He told me to make sure the factory guys look into it when we are next in Hohenwald.

 

I mentioned to him that I was always careful to keep the tires at 50psi (as indicated on the Oliver tongue sticker), but that I had noticed that the tires were rated on the sidewall for 65psi.  He said I should ignore the sticker and keep the tires at 65psi - and that maybe that was the cause of the problem.  

 

If so - I have factory provided tires that are prematurely in need of replacement because I have been keeping them inflated to the factory prescribed air pressure.  Huh?!?!  *grrrr*  

 

And that still doesn't completely explain the uneven nature of the wear.

 

What pressure do you all keep your Oliver tires inflated to? 50psi? 65psi? Something else?

 

What sort of tire wear have you noticed? Anything uneven?

 

Any thoughts on this?

 

Thanks!

 

- Chris

[desmo_pilot]

Chris,

 

As an avid car freak, I really doubt your issue is air pressure. Under inflation will almost always wear both outside edges of a tire and you would also see this on both tires, not just the outer edge of one tire. Sounds to me like the camber is out of whack on the curb side. Our axles are not adjustable like an automobile, but I'm wondering if trailer shop could bend it slightly using heat and a press. Otherwise, it would likely mean axle replacement.

 

One thing to check is to get a angle measure device(~$15, see the link below) from Home Depot/Lowes/Ace and a straight edge about two feet long. Inflate both tires to the same pressure, place the straight edge vertically across the tire, then place the angle tool on the outside of the straight edge. You should read anywhere from 0 to 2 or 3 degrees negative(meaning the top of the tire leans inward slightly). My guess is that your curb side is reading positive camber, meaning that the top is leaning outward a few degrees. Now unfortunately, reading across the tire is the most accurate due to tire bulge, etc. But, it will give you an idea if something is wrong. The most accurate way would be to have a straight edge the fits perfectly on the rim edge and doesn't touch the tire. You could always cut the straight edge to fit if you wanted to.

 

You other option is to go to an alignment shop and have them do just a camber check for you. Likely would cost about $30 and shouldn't be more than $40ish.

 

Here is the link to the angle tool. http://www.acehardware.com/sm-ace-magne ... 85951.html

 

Let us know what you find out.

 

Kyle

[herm]

I haven't racked up enough miles to notice any uneven wear (actually no noticable wear whatsoever yet), but I think Kyle's analysis is spot on. I don't keep my tires at 65 psi either, largely because I don't need the full load capacity of the tire and it offers a little more cushioning (in theory anyway). I don't believe there's any requirement to maintain max. psi, unless it's for load capacity reasons.

 

Anyone else noticed the little 'kink' in the middle of the axle? On mine it points up, i.e. slightly more ground clearance in the center of the axle versus the ends. Any chance this could also produce the positive camber at the wheel which Kyle was referring to? I suppose this doesn't explain the curbside-only nature of the problem though.

 

Herm

[astrocaster]

Chris,

I know that I do not have even close to the amount of RV experience that some others here have, but I have learned a lot about trailer axles, wheels, and tires in the last couple of weeks, and one of the things that seems to be stressed in all of the sources I have consulted, including the RV repair shop I have taken our Oliver to, is that trailer tires should be inflated to the pressure indicated on the tire sidewall, in order for the tire to have the load capacity indicated on the sidewall, and for maximum tire life. Unlike passenger tires, trailer tires--particularly those with sizes that begin with "ST" (for "Special Trailer")--are designed to be inflated at the pressure indicated on the sidewall, as their minimal and normal pressure.

 

One other thing to consider regarding the additional wear on the outside of the curb-side tire, is that due to the domed shape of most highways and the fact that we usually tow our trailers in the rightmost lane, this can tilt the trailer a little to the curb side, and the outside edge of the curb-side tire may bear a little more weight than the other three tire edges on a single-axle trailer. With the Oliver, this tilt may be somewhat mitigated by the additional weight of the refrigerator, furnace, and water heater on the street side, but the tilt of the road may still be a significant factor, in my opinion, if the tires are not fully inflated to the specifications on the sidewall. It seems to me that an underinflated tire would flex more, and with the additional outward lateral force from the tilt of the road, the curb-side tire could flex enough to present much more of the outside edge for wear.

 

Herm, I checked with our RV mechanic about the slight upward arch of the axle in the middle. He said that is how they are designed, to provide positive camber, as you suggest.

 

Steve

[jam49]

Hello to all,

I just returned from Camping World. Because of all the relevant discussion for all of us concerning the PSI of the tires, I asked the technician while I was there what his opinion was on tire pressure. He said the Oliver is such a light trailer that it wasn't necessary to keep it at 80 psi which is on the side of my tires. He said he would keep it inflated to 65 psi. Mine were at 50 psi. I went with the middle recommendation. He said that the tires on the Oliver were those used for heavy rigs and that 65 psi should do fine unless I carried a heavy load which I don't plan on doing at this time. (just my 2 Cents for whatever it is worth). jam49

[astrocaster]

I just realized that in my previous post in this thread, I said that the refrigerator, furnace, and water heater are on the street side of the trailer. This is incorrect, of course: they are on the curb side. Sorry if I caused any confusion. I appreciate the fact that no one gave me a hard time about that! I believe that the fresh water tank is also on the curb side, so if you are towing the trailer with a full tank of water, then there is even more weight on the curb-side tire.

 

Steve

[DCKiefer]

I second the motion that the tires should be inflated to at least 65 psi. I watch tires closely and after just a couple of trips noted the outer edges taking more wear.

[herm]

There's obviously a lot of conflicting information regarding psi, and I don't really want to add to the confusion; however, this link from Goodyear http://goodyear.com/rv/tirecare/index.html supports the practice of inflating to the actually load requirement of the axle, not the maximum allowable psi of the tire. There's also a link to load/inflaction tables that give you the psi required to achieve a given load limit for various tire sizes.

 

Based on this data, my 225/75R15 Load Range D tires inflated to only 50psi are capable of 2150 lbs. per tire, adequate for my actual weight (or should I say, predicted actual weight...I haven't actually been to a scale yet). AFAIK, there shouldn't be any harm in inflating to the full 65psi maximum, but it shouldn't be required for the performance of the tire. I really have a hard time believing that the abnormal tire wear some are experiencing is caused by operating the tires at 50psi.

 

jam49, I'm curious. What type of tires did you get on your Oliver? Being that they have a max. of 80psi, I'm guessing they are Load Range E? Is that something you selected, or is this the new Oliver standard? If true, your CW technician is correct...it's way more tire than you actually need.

 

Herm

[astrocaster]

Herm is quite correct that there is a lot of conflicting information regarding the proper tire inflation pressure for trailer tires. Let me supply just a bit more food for thought regarding inflating trailer tires (as opposed to passenger tires) to the pressure indicated on the sidewalls, and why we choose to do so:

 

It may well be that different trailer tire manufacturers have different approaches to the necessary inflation pressures for their tires. Although Goodyear recommends inflating their tires to the actual load requirement at each individual tire, using a load/inflation table, and setting the pressure for all tires on each axle at what is needed for the tire with the heaviest load, Duro Tire and Wheel recommends that their trailer tires be inflated to the recommended PSI on the sidewall (see point 1 under safety in the link below):

 

http://www.durotire.com/productslisting.php?productspage=274

 

We currently have Duro tires on our Oliver, so we will continue to follow their recommendation.

 

We've purchased tires at our local America's Tire (Discount Tire in some parts of the country) outlet and have always been pleased with their service and professionalism. They, too, recommend that trailer tires be inflated to the maximum inflation indicated on the sidewall (see the left panel and the first bullet under "Inflation" in the link below):

 

http://www.discounttire.com/dtcs/infoTrailerTireFacts.dos

 

Underinflation of trailer tires seems to be universally acknowledged as the most frequent cause of trailer tire failure. From all that I have read, and from the discussion I had with our RV mechanic, underinflation is particularly deadly for trailer tires, allowing the sidewalls to flex and lead to early tire failure. For me, the choice to inflate the tires to the PSI on the sidewall assures us that the tires are not underinflated under a variety of loads, as long as we make sure that we do not exceed each tire's load carrying capacity.

 

Steve

[herm]

Thanks for providing the supporting links, Steve. In light of this, I will err on the side of caution (and perhaps give myself an extra margin of safety) and inflate to the 65psi max. pressure. Also, I should point out that my tires are made by BCT (Beijing Capital Tire), and I could not find any documentation by the mfg. that supports my previous opinion. Thanks to everyone who contributed to the discussion!

 

As to the issue of curb-side outer-edge wear, hopefully Chris & Cherie will let us know if the increased tire pressure solves anything. Since they are a non-directional tire (at least mine are), one could extend the life by rotating side-to-side...a relatively easy task thanks to the power jacks.

 

Herm

[jam49]

Thanks for providing the supporting links, Steve. In light of this, I will err on the side of caution (and perhaps give myself an extra margin of safety) and inflate to the 65psi max. pressure. Also, I should point out that my tires are made by BCT (Beijing Capital Tire), and I could not find any documentation by the mfg. that supports my previous opinion. Thanks to everyone who contributed to the discussion!

 

As to the issue of curb-side outer-edge wear, hopefully Chris & Cherie will let us know if the increased tire pressure solves anything. Since they are a non-directional tire (at least mine are), one could extend the life by rotating side-to-side...a relatively easy task thanks to the power jacks.

 

Herm

 

My tires are also BCT JK42 ST225/175R15 with a load range of D. I asked the technician where he saw 80 and he said right here. All I saw was an 8 and since I am learning all kinds of new things I took him at his word. I am going to leave the tires inflated to 65psi. jam49

[jam49]

Herm,

I went and looked at both tires. I have a D range on the right tire and an E range on the left tire. I am going to contact Robert to see if this matters. jam49

[astrocaster]

Herm, I am happy to help with the links I provided.

 

Jam49, it seems very odd that you would have a load range D tire on one side and load range E on the other. As Herm suggests, the load range E tire explains why you were given the 80 psi reference by the Camping World technician. Load range E tires are commonly inflated to 80 psi, while load range D tires are commonly inflated to 65 psi. I think that you have a good idea to check with Robert on this.

 

Steve

[jam49]

I finally found where he saw the 80 psi. I have been searching for everything I need to know about the Oliver travel trailer starting with the tires since this is so important. I went back a third time in the dark flashlight in hand to see if I could find the 80 psi the technician said was right there. Finally found it in small letters and numbers where I found 2540 lbs at 65psi on the D tire and 2830 lbs at 80psi on the E tire. Tomorrow I will tackle taking the spare tire cover off and seeing what that tire is rated.

Did warranty information come with the tires when you picked up your TT? j

[DCKiefer]

I think you may be disappointed with the spare unless they have made some recent changes. Mine was a load range C and a 205. If yours is take a look at my post titled Full Size Spare. It requires a modification to the tire cover to get the cover mounted over the 225 size tire.

[jam49]

Talked to Robert today about the tire mismatch. He said it should have been caught before Revilo left the factory and that it would be taken care of right away. I asked about the spare tire and he said it is to be used to get to the nearest place to fix the damaged tire not to be used as a road tire.

[DCKiefer]

Two comments. I understand the spare tire is only intended for temporary use, it just seems strange to me to have two tires on the trailer not only of a different load rating, but of a different width on the trailer. I don't think it's a good idea since with my calculations the smaller spare would be nearly 250lbs over weight. I'm just not comfortable with the smaller spare and especially since the tire cover will except the larger tire with on slight modifications.

 

The second thing, I took my load rated E's up to 80 psi as recommend by others. I had some concern that they migth be over inflated given the weight of the trailer. I check the foot print the tire made at 80 psi and it great. I think this might take care of the unusual wear I was seeing and others had described.

 

My advice on this whole tire thing is don't mess around with them. Have the right tire all around, keep thme at the max psi and you will not get stuck.

[jam49]

Robert took care of the tire mismatch error right away. I received an "E" tire Friday night and I took it to Discount Tires Saturday morning to get it switched over. I am glad to have that taken care of as I slowly prepare for the big 1st time adventure with Revilo. Jennifer

[technomadia]

An update on our tire situation...

 

 

It does indeed appear to be a camber issue with the axle, as after rotating the tires (and adjusting the PSI as per Jim Oliver's recommendation), we've had the same exact wear pattern on the new non-bald tire. It started showing up somewhere around New Mexico (just about 1200 miles after the tire rotation). Upon arriving in St. Louis - it was pretty much even with the other tire.

 

We're currently meandering our way towards Hohenwald, where new tires and axle await us. The Oliver folks sure do treat their customers right. We're looking forward to seeing all the Oliver folks this week!

 

Thanks for all the help in diagnosing the potential causes of this.

 

- Cherie