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Old 05-01-2013, 01:03 AM   #15
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Since you are asking for opinions, I'll give you mine.
In my opinion, the best 15" tire that would handle the weight of your trailer is the Michelin LTX M/S2 P 235/75/15XL. It is a "P" tire, so the weight rating on the sidewall must be derated when used on a trailer.

Have fun reading!
Derated by how much?
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Old 05-01-2013, 06:07 AM   #16
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Maxxis M8008 ST Radial 225/75R15 10 ply.

M8008 ST Radial

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Old 05-01-2013, 06:26 AM   #17
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Derated by how much?
By a factor of 1.1
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Old 05-01-2013, 06:46 AM   #18
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Quote:
Originally Posted by Globie64 View Post
Derated by how much?
The factor is 1.1 Thanks Capri Racer.

So for this Michelin P tire it is 2183/1.1=1984.5
The same load rating (adjusted) as a load range C LT 235/75/15 tire at 50 PSI.
Michelin used to make this tire as an LT load range C when it was the LTX M/S, but it was made a P tire when the LTX M/S2 replaced it. Not sure why exactly.
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Old 05-01-2013, 07:18 AM   #19
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A number of years ago we ditched the Good Years for Carlisle ten plys on our 2004 30' S/O and just replaced them again. They've provided us with good service; however, I was a bit shocked at how much the cost of new tires has increased during the past four years! Good luck.
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Old 05-01-2013, 10:56 AM   #20
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The tire derating regulation is:

49 CFR 571.110
Tire selection and rims and motor home/recreation vehicle trailer load carrying capacity information for motor vehicles with a GVWR of 4,536 kilograms (10,000 pounds) or less.

S4.2.2.1
Except as provided in S4.2.2.2, the sum of the maximum load ratings of the tires fitted to an axle shall not be less than the GAWR of the axle system as specified on the vehicle's certification label required by 49 CFR part 567. If the certification label shows more than one GAWR for the axle system, the sum shall be not less than the GAWR corresponding to the size designation of the tires fitted to the axle.

S4.2.2.2
When passenger car tires are installed on an MPV, truck, bus, or trailer, each tire's load rating is reduced by dividing it by 1.10 before determining, under S4.2.2.1, the sum of the maximum load ratings of the tires fitted to an axle.

S4.2.2.3
(a) For vehicles, except trailers with no designated seating positions, equipped with passenger car tires, the vehicle normal load on the tire shall be no greater than 94 percent of the derated load rating at the vehicle manufacturer's recommended cold inflation pressure for that tire.
(b) For vehicles, except trailers with no designated seating positions, equipped with LT tires, the vehicle normal load on the tire shall be no greater than 94 percent of the load rating at the vehicle manufacturer's recommended cold inflation pressure for that tire.

One could put six Michelin LTX (P) 235/75R15 XL tires on your existing 15" rims at 50psi and have a derated load capacity of 11,898 pounds versus 13,098 pounds for six per the tire sidewall rating. That would be a 15% safety factor at the derated capacity for a trailer with a 10,000 pound GVW. And the 50psi is lower than the 65 psi of ST tires, so the wheels would have less internal stress.

I installed five (including the spare) of these Michelin tires on my 25FB that has a GVW of 7,300 pounds and I purchased them at Costco. I carried the wheels in two at a time for the installation so the trailer was not in the Costco parking lot.
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Old 05-02-2013, 05:58 AM   #21
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Quote:
Originally Posted by Top View Post
The factor is 1.1 Thanks Capri Racer.

So for this Michelin P tire it is 2183/1.1=1984.5
The same load rating (adjusted) as a load range C LT 235/75/15 tire at 50 PSI.
Michelin used to make this tire as an LT load range C when it was the LTX M/S, but it was made a P tire when the LTX M/S2 replaced it. Not sure why exactly.
We've had this discussion before, but a P235/75R15 XL has the same maximum load as an LT235/75R15 Load Range C but at different pressures. (35 psi vs 50 psi). These are different animals, but the specs look similar.

Why the difference? Because P metric tires are designed to be flexible and LT metric tires are designed to carry high loads compared to the amount of material they use and the space they occupy, so the rubber in LT tires isn't very tolerant of flexing. I hope you notice that the P metric tire is on the large end of the P metric sizing range, and the LT is on the small end of the LT size range.
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Old 05-02-2013, 10:37 AM   #22
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Okay, so which would be better for a trailer, a P rated tire with more flex, maybe transmitting less vibration to the trailer, or an LT, with more load carrying... reserve?
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Old 05-02-2013, 01:58 PM   #23
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The "best" trailer tires (all trailer types) would be commercial service tires such as:

MICHELIN XPS Rib

and

BRIDGESTONE Duravis r250

Everything else is a step down, but the

BFGoodrich Commercial T/A

is a good choice, albeit at a lower price.

As the above tires are expected to roll a lot of miles in their life-time (where TT's generally don't), the difficulties start to show up as these are 16" tires (and A/S rides on OEM 15"). So for those not wanting to change wheel size, the MICHELIN mentioned in earlier posts are popular.

ST tires are about good enough for a trailer wihere the payload $$ value is low.

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Old 05-03-2013, 07:08 AM   #24
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Originally Posted by Globie64 View Post
Okay, so which would be better for a trailer, a P rated tire with more flex, maybe transmitting less vibration to the trailer, or an LT, with more load carrying... reserve?
First I think your premise about reserve is wrong. They have the same load carrying capacity, and the way the tire industry uses the term "reserve" (difference between rated capacity and the actual load), means there is no difference in reserve capacity.

But if you are asking the question, which tire is likely to have been more over-designed (which is the way the trailer folks are using the word), then I would have to give the nod to the P metric version - BUT - I think there is more to this.

First, the idea that P metric tires are better designed is just a feeling on my part and I don't have any substantial data to back it up. It's based on the idea that among the fall out of the Ford/Firestone situation was an examination by the tire manufacturers of how well tires were performing and passenger car tires on SUV's was given a lot of scrutiny - and that would have included this particular size.

Second, the order that these tires were looked was: 1) Passenger car tires on SUV's, 2) Passenger car tires on cars, and 3) LT tires. So I think LT tires would not have benefited from as long of time of scrutiny and therefore would not be as far along in the development process.

Third, I think the question of which is better is also dependent on what your intended use of the trailer is. If you are only using the trailer on highways and never in primitive campsites, then the LT metric might be better. But I would think that high speed runs would be better with the P metric tire.
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Old 05-03-2013, 08:54 AM   #25
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Quote:
Originally Posted by slowmover View Post
The "best" trailer tires (all trailer types) would be commercial service tires such as:

MICHELIN XPS Rib

and

BRIDGESTONE Duravis r250

Everything else is a step down, but the

BFGoodrich Commercial T/A

is a good choice, albeit at a lower price.

As the above tires are expected to roll a lot of miles in their life-time (where TT's generally don't), the difficulties start to show up as these are 16" tires (and A/S rides on OEM 15"). So for those not wanting to change wheel size, the MICHELIN mentioned in earlier posts are popular.

ST tires are about good enough for a trailer wihere the payload $$ value is low.

.
There is a commercial 15" tire. It is the Continental Vanco 2, 225/70R15C. The C at the end stands for commercial. It will lower the trailer a little less than 1/2".
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Old 05-05-2013, 04:03 AM   #26
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Unfortunately, the letter at the end of a tire description is the Load Range rating of the tire, so the letter "C" does not mean commercial in the post above.
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Old 05-05-2013, 06:18 AM   #27
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Unfortunately, the letter at the end of a tire description is the Load Range rating of the tire, so the letter "C" does not mean commercial in the post above.
I am sorry, but in Europe, they use the letter "C" behind the tire size to mean a "Commercial" tire as opposed to a "passenger car" tire. In the US, we refer to these types of tires are "LT" tires, because of the letters in front of the tire size.

And in this case, the term "commercial" is used differently than when it appears in the name of the tire. If the term appears in the name of the tire, it means the tire was designed to be used in a commercial application and may contain long wearing tread compounds and a heavy duty casing (but don't quote me on that).

Let me give you some examples.

195/70R15C 104/102R 8 PR (Load Range D) Continental Vanco 2

LT235/85R16 120/116Q Load Range E, BF Goodrich Commercial T/A All Season.

You can look both of these up on Tire Rack's web site.
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Old 05-05-2013, 07:26 AM   #28
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Unfortunately, the letter at the end of a tire description is the Load Range rating of the tire, so the letter "C" does not mean commercial in the post above.
This is a "D" rated tire, look it up
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