Another Tire Question

shakyjay wrote:
Chuck I had not thought about the rim width. You are right they are only 5". Looks like that could be a limiting factor. The rims do not have a visible weight or psi rating anywhere on them. If it is there it must be stamped on the inside which really does not help as that means I won't know until they take the tire off the rim. I don't think there should be a problem going from C to D or which is going from 50 to 65 psi. I can see where going to 80 psi with and E rating could be an issue.

Wheels like tires are pressure and capacity rated. Anyone/persons that says all 15" steel wheels are pressure rated to 80 psi has no business offering advise or tell others to ignore the wheel manufacturers pressure ratings. If your steel wheels have no pressure ratings then its time to contact the wheel manufacture. You sure don't want a split bead seat on the wheel. Just like the over pressured tire it can have a sudden loss of pressure. Even tire manufacturers warn to use the proper pressure and capacity wheel for the tire.

Dexstar has 15" steel wheels rated at 50-65-75 and 80 psi.

Chuck makes a good point on using the proper width wheel for a particular tire. Same goes for pressure and capacity as one size don't fit all. Lets be safe out here.

Chuck&Gail wrote:
Several points. First, as said, what are your RIMS rated for? Rating usually stamped on rear, or in valley UNDER the tire. Putting LR-D on a LR-C rim is a THIRTY PERCENT OVERLOAD. Not what I call safe. Obviously LR-E is an even worse overload.

Second what is your current rim WIDTH? Most ST205/75R15's I've seen are mounted on 5 or 5.5" rim widths. Most ST225/75R15's seem to require a 6" minimum rim width. Again, be careful what you do.

I looked at going to 225's on my cargo trailer to replace the 205's. Looking stopped when I saw the rim width. Fine for 205's but definitely narrow than the min spec for 225's. So went with LRD 205's and checked the wheels which are rated for 65psi.

towmax's on my outback were fine, no issues,replaced them with Maxxis LRE when they were worn out. The lasted about 5K fewer miles than the Maxxis on my cargo trailer, but part of that could very well be the % of rated load they were run at.

IMHO the best thing you can do to minimize the chance of a blowout on a trailer, regardless of tires is to install a TPMS. From personal experience, you won't notice a tire going down from a slow leak on a trailer, unlike a car. Low pressure=overload=heat=blowout. In my case I caught both of them at a roadside stop, nail in the tire, but much longer and I would likely had a blowout. TPMS will at least give you a warning of slow presssure loss.

Rim width is a limiting factor as is psi rating or weight rating. If you can't find any info on the side of your rims, it may be stamped, but under the tires. Dismount a tire and check. If you don't like the numbers, new rims and tires might be the answer. Good luck.

jimnlin is misinformed about steel wheels not being able to take 80 psi.
side bearing loads and the strength of the wheel being able to support a load are exponentially greater than tire pressure within a wheel .
further , when these rv or light truck wheels fail they do not do so catastophically .
rather they develop a crack at a "shoulder" and they fail because they can no longer maintain a constant pressure.

I guess the manufacturer of the wheels on my last three trailers are also misinformed.

Current STEEL wheels on Keystone Outback rated for 2600#. Came with ST225/75R15 LR-D. Note LR-E specs 2830# for 80 psi in that size.

Steel(?) wheels on Thor Wanderer rated for 65 psi, 2150#. Came with ST205/75R15 LR-C.

Current STEEL wheels on Mirage rated for 50 psi, 1820#. Came with ST205/75R15 LR-C.

Everyone can do as they wish. I wish to not exceed published (or stamped) specs.

Lowsuv wrote:
jimnlin is misinformed about steel wheels not being able to take 80 psi.
side bearing loads and the strength of the wheel being able to support a load are exponentially greater than tire pressure within a wheel .
further , when these rv or light truck wheels fail they do not do so catastophically .
rather they develop a crack at a "shoulder" and they fail because they can no longer maintain a constant pressure.

I never said a steel wheel wasn't rated at 80 psi. See my above post on different wheel pressure ratings.
I base my opinion on facts from the wheel makers and my personal and other operators experience of busted out or cracked steel wheel centers and split bead seat flanges from using the wrong capacity/pressure rated wheels and from and wheel dealers recommendations.

All steel wheels are stamped from different material thicknesses so one size don't fit all.

when these rv or light truck wheels fail they do not do so catastophically .

Busted/cracked wheel centers and busted valleys are not uncommon on LDTs out here in the real world. Now granted the vast majority of RV folks/persons don't carry max axle/wheel or tire loads so its possible that some could come to the erroneous conclusion that wheels don't fail or especially don't fail catastrophically. Wheels can and have failed from using the wrong capacity(s).

nothing in the charts quoted indicates that the wheels are only rated for 65 psi.
the charts are indicating the maximum load rating of that particular size and load range tire and the psi that the tires must be inflated to to carry that weight .
to limit the upgrade in tire size and psi limits the safety that can be built in by using a Load Range D ( 65 psi ) or Load Range E ( 80 psi ) tire .
The Tire is the Weak Link in the weight rating carried .
The steel wheel is not weaker than the tire . The steel wheel can take considerably more psi than the tire can . That is the reality and it also is logical.
A TPMS system although a good idea is not as good as spending that same expense to upgrade the current tire to one with a higher load rating as shown on the sidewall .
Hundred of thousands of GM trucks have been shipped with 245/75R16 tires as factory equipment . My swag guess is that 25 % of those tires have been upgraded to a 265/75R16 tire at replacement time . The factory GM wheels are 6.5 inches wide . Although the 265/75 tire calls for a 7 inch to 9 inch wheel width there really are no problems due to a narrow rim width other than it is not optimum.
I have been using the 265 instead of the 245 on factory 6.5 " wheels since 1998 .
For the record i use 2 sets of wheels. My snow tires are on factory 6.5" GM aluminum wheels . My summer Michelin 265/75r16E are mounted on 8 inch wide Weld aluminum wheels. The truck handles better with the 8" wheel and the summer tires of course.
it is less safe to continue using the factory supplied tire rated for 1820 # than upgrading to a higher rated tire (say 2271# ) even though a higher psi is needed .
brand is far less important than the rated load capacity .
tire rack can be your friend .
check out the specs from their trailer tire tab and do some comparisons for yourself .
because the continental Vanco 2 tire is rated on the LT criteria rather than the ST criteria it is a 99 mph tire . i would consider that particular tire to be the class of the field for RV use . it is factory equipment on the mercedes sprinter vans and motorhomes .

here is the web link with the specs:

http://www.tirerack.com/tires/tires.jsp?tireMake=Continental&tireModel=Vanco+2&sidewall=Blackwall&partnum=27R5V2&tab=Specs