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Old 01-08-2016, 09:28 AM   #21
hitchikerman
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o-k after further review I talked with the wheel manufacture and he suggested that since the wheel is only rated for 2600# that I would be overloading the wheel so I guess I'll be replacing with the D range tire. So after looking at the specs of my fifthwheel the load carrying capacity of trailer 3100#...and if I have four tires at 2540# each totaling 10160# total capacity. The dry weight of the trailer is 8630# leaving me 1530# carrying capacity. Is this where the pin weight makes up the difference?
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Old 01-08-2016, 10:17 AM   #22
cw3jason
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yes, except you do not use the tire weights, you use the axle weight ratings. the tire weights are usually and should be slightly more when added then the axle weight.

the carrying capacity of the frame and suspension is what makes up your trailer GVWR
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Old 01-11-2016, 09:11 AM   #23
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Discount Tire sells me Carlisle LRE's for the same price as LRD's for my car hauler and two-axle enclosed utility trailer. With metal stems and a balance job, I feel better prepared for what lies ahead. Carlisle or Maxxis are the only LRE trailer tires I use anymore.
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Old 01-18-2016, 08:58 AM   #24
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You know, ST tire manufacturer's are very adamant about tire inflation pressures for their tires and always recommend 100% of tire sidewall pressures to be used for Original Equipment tires.

Some time ago in a phone conversation with a Maxxis tire rep the subject for replacement tires was discussed. His "canned" answer was to use whatever was recommended by the vehicle manufacturer. That would include using LRD tire pressures for LRE replacements. Advantage of the LRE tires? Not measurable. My recommendation; New rims and LRE tires at 80 psi. For the OP that's going to provide about 13% excess load capacity in reserve.
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Old 01-18-2016, 12:57 PM   #25
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I understand that rims and tires might not always match but I have been told and have experienced that runnung at less than the sidewall psi of a tire will damage the tire. Might not have a blowout right away but the tire could heat up to the point the tread comes off the rest of the tire.
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Old 01-18-2016, 02:48 PM   #26
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Almost every car tire I own gets run at less than sidewall pressure. My understanding is that sidewall pressure is maximum and also the setting that warrants rated load.
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Old 01-19-2016, 12:41 AM   #27
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Quote:
Originally Posted by dcg9381 View Post
Almost every car tire I own gets run at less than sidewall pressure. My understanding is that sidewall pressure is maximum and also the setting that warrants rated load.
They are regulated differently. Read FMVSS 571.110 paragraph S4.2.2.2
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Old 02-13-2016, 02:43 AM   #28
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Quote:
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The DOT does not require the rims on our trailers to have load capacitie or psi limiting figures displayed on each individual rim.
That corresponds with what I'm dealing with right now. I was debating about whether to upgrade to load range E's or not (trailer came with D's) and I couldn't find any stamp referring to max PSI on the back side of the wheel spokes.

I did find the Max load rating, which made me think it was rated as compatible with the E's (it says 5/2150&6/2830lbs) and since it's a 6 lug. . .

This was further verified on wheel mfg website http://www.sendelwheel.com. Website says mine are rated for 80PSI as long as it's the 6 lug version.

But anyway, yeah, it won't necessarily have the PSI on the back of the wheel. If it says SenDel on it, though, that's the mfg and the specs should be able to be found on the website I linked.
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Old 02-13-2016, 02:29 PM   #29
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In an earlier post in this thread I said the tire pressures for your Tow Vehicles (TV) are different. It’s a confusion factor that needs more explanation.

All automotive tires such as those on cars, SUVs, multi passenger vehicles and even motorcycles must provide a percentage of load capacity reserves via inflation pressures. (Do a test, look a tire placard for your TV and do some math with a tire chart).

RV trailer manufacturer's are not required to any percentage of reserve load capacity. In fact, a trailer manufacturer can install two 3000# tires on 6000# (GAWR) axles and meet the minimum DOT fitment requirement. Most ST tire manufacturers quit making the 3000# tires because of that.

Vehicle manufacturer have the authority to set GAWR loads by making a 5200# axle a 5080# GAWR axle. Some still do it. Some will find tires rated at 2540# on those 5080# axles. I call any of those tire fitments trailer manufacturer bombs. I’m hoping that the next round of the NHTSA tire rules committee meetings will enact a 12%/15% minimum load capacity reserve rule for all trailer tire fitments. The RMA lobbied for that in the last go-around and was out voted. Availability and costs were contributing factors.
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Old 02-13-2016, 04:19 PM   #30
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CW,

First, thanks for all the great info. I always find your posts informative.

I hope you can clarify something for me:

You indicate that there is no load carrying benefit in using a ST E rated tire at 65 psi, since the load capacity only increases above 65 psi to a max at 80 psi. That makes sense to me.

What is not clear to me is if there are any negative consequences in terms of tire durability and tire life if running a ST E rated tire at only 65 psi.

The reason I ask is that I have nearly 50% reserve capacity running ST D rated tires on my relatively small and light trailer (GVWR 6800, GAWR 4400 tandem axles, 2540 ST D tires and 2830/80 psi max wheels). On the surface it would seem that I really have no reason, when the time comes, to upgrade to a ST E rated tire since I already have nearly 50% reserve capacity with the ST D rated tires. But if I was to upgrade to ST E rated tires for the few extra dollars, my thought was to still run at 65 psi since I would not want to roughen the ride. But is there a durability or reliability benefit, or consequence, in running ST E rated tire at 65 psi over a ST D rated tire at 65 psi?

Or should I not be concerned with the assumed rougher ride running a ST E tire at 80 psi and benefit from the 60+% load carrying reserve?

I look forward to reading your insights.
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Old 02-13-2016, 07:42 PM   #31
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Quote:
Originally Posted by slow View Post

You indicate that there is no load carrying benefit in using a ST E rated tire at 65 psi, since the load capacity only increases above 65 psi to a max at 80 psi. That makes sense to me.

What is not clear to me is if there are any negative consequences in terms of tire durability and tire life if running a ST E rated tire at only 65 psi.
Every engineer I’ve talked with about going up a load range says the same thing. It’s in the charts. They say a LRE tire inflated to the PSI of a LRD tire makes it a LRD tire. You might find a tire that is more durable but if that’s so, it’s probably more durable in all load ranges.

Inflating a LRE tire to LRD inflation pressures is a subject for the tire manufacturer. Carlisle has always touted full sidewall pressures for their ST tires. Maxxis will stick to whatever the vehicle manufacturer recommends. Most others are like Carlisle. You’re always going to be safer with a higher inflation pressure because you’re less likely to heat the tires.

The bottom line probably has the best answer. Use replacement tires that provide equal or greater load capacity than the OE tires. That would mean a tire of the same size and design would use the same tire inflation pressure as the OE tires. The Keystone owner’s manuals are going to tell you to seek their advice. IMO they are going to tell you to use the same size as the OE tires unless they have previously authorized an optional fitment for your model trailer. Personally I went up a load range and inflated to max sidewall. Works very good for me. My trailer came with ST235/80R16D tires on 6000# GAWR axles. I went up to the ST235/80R16E, problems solved.

Note: I would not recommend fooling around with rims not having the PSI rating of the installed tires.
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Old 02-13-2016, 08:25 PM   #32
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Thanks for the insights CW, much appreciated.


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