why not car tires

[acadianbob]

Originally Posted by sidney

What's the difference between taking off snow tires and letting them sit for 6 months then putting them back on your vehicle... then putting your summer tires back on after sitting 6 months?

Your "off duty" tires probably don't sit outside in the elements and sun. Big difference.

[sidney]

Originally Posted by acadianbob

Your "off duty" tires probably don't sit outside in the elements and sun. Big difference.

That's true... but neither are the trailer tires.

It's easy to keep your tires out of the elements and out of sun light while still on the trailer.

[Airdale]

Originally Posted by sidney

What's the difference between taking off snow tires and letting them sit for 6 months then putting them back on your vehicle... then putting your summer tires back on after sitting 6 months?

There is no weight on them.

A

[sidney]

Originally Posted by Airdale

There is no weight on them.

A

You can take the majority of weight off your trailer tires (and springs) by supporting the trailer on jack stands while in storage.

[wmtire]

Originally Posted by Oakman

Most of the passenger car tires I've seen don't have anywhere near the load rating of the ST tires. I can understand folks using LT tires but not passenger "P" tires.

Oakman has really hit the nail on the head, for the biggest reason you shouldn't use passenger tires on trailers..........as well as the other reasons that many members have pointed out (internal construction, chemical composition, etc).

Points to ponder:

1. If passenger designated tires were the answer (and legal), then trailer manufacturers would use them, since they are usually cheaper in price and more readibly available.

2. I stated "legal" above because vehicle and trailer/RV manufacturers must adhere to Federal Motor Vehicle Safety Standards (FMVSS). These standards state what the load capacity has to be for tires mounted on vehicles and trailers/RV's. The tires have to carry what the axles are capable of.

We need to familiarize ourselves with a few parts of the FMVSS, which are the regulations for trailers/RV's under 10,000 pounds GVWR and the ones for trailers/RV's over 10,000 pounds GVWR..................as well as to what tires can meet the specs in the regulations.

Under 10,000 pounds:
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 - Federal Motor Carrier Safety Administration

S4.2.2 Tire load limits for multipurpose passenger vehicles, trucks, buses, and trailers.

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.

Over 10,000 pounds:
Tire selection and rims and motor home/recreation vehicle trailer load carrying capacity information for motor vehicles with a GVWR of more than 4,536 kilograms (10,000 pounds). - Federal Motor Carrier Safety Administration

S2. Purpose. The purpose of this standard is to provide safe operational performance by ensuring that vehicles to which it applies are equipped with tires of adequate size and load rating and with rims of appropriate size and type designation, and by ensuring that consumers are informed of motor home/recreation vehicle trailer load carrying capacity.


S5.1.2 Except in the case of a vehicle which has a speed attainable in 3.2 kilometers of 80 kilometers per hour or less, the sum of the maximum load ratings of the tires fitted to an axle shall be not less than the gross axle weight rating (GAWR) of the axle system as specified on the vehicle's certification label required by 49 CFR part 567. Except in the case of a vehicle which has a speed attainable in 2 miles of 50 mph or less, the sum of the maximum load ratings of the tires fitted to an axle shall be not less than the gross axle weight rating (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. If the size designation of the tires fitted to the axle does not appear on the certification label, the sum shall be not less than the lowest GAWR appearing on the label. When a passenger car tire is installed on a multipurpose passenger vehicle, truck, bus, or trailer, the tire's load rating shall be reduced by dividing by 1.10 before calculating the sum (i.e., the sum of the load ratings of the tires on each axle, when the tires' load carrying capacity at the recommended tire cold inflation pressure is reduced by dividing by 1.10, must be appropriate for the GAWR).

[wpredock]

lots of interesting data. my original question has been answered. i will use nothing but top of the line trailer tires when the time comes , and keep them well maintained. mainly monitoring the tire pressure.

[RKR]

I would definitely not use P tires. You can Google ST vs LT tires though and get many threads from different forums that go back years.
The discussions can get pretty heated on both sides. There seems to be many people that swear by LT tires if the proper load rating is used and the rim can handle the air pressure. There's a lot of talk about " China bomb" ST tires and such.
From what I have read so far it seems that a lot of former ST users have pics and horror stories of ST tire failures and such. I'm sure that a fair share of those are due to operator negligence , road hazard and such.
The interesting thing is that I haven't yet read where LT tire user went back to using an ST tire. I'm not saying it's not out there I'm just saying that I haven't read any yet.
If anybody has any thread links or experience with LT users going back to ST tires please share the link. I have already read a lot of the documentation and official recommendations that have been pasted on threads. I would like to read some real world experience.
I have pulled many types of trailers for years. I always pre trip my vehicles before hitting the road so I already know the importance of tire care. I'm just a little concerned about my ST tires causing me a problem. I have new trailer and will be carefully monitoring my ST tires for sure.

[ependydad]

RKR, all I can add is additional conjecture. But I decided to stick with ST and simply opted for a high quality brand with a proven track record (Maxxis). It gives me peace of mind.

[RKR]

Originally Posted by ependydad

RKR, all I can add is additional conjecture. But I decided to stick with ST and simply opted for a high quality brand with a proven track record (Maxxis). It gives me peace of mind.

I'm running Towmaster STR's on 16" rims. I'll take care of them and keep a very close eye on them. Hopefully they will hold up. I really don't want to spend money upgrading new tires to another set of new tires.

[ependydad]

Originally Posted by RKR

I'm running Towmaster STR's on 16" rims. I'll take care of them and keep a very close eye on them. Hopefully they will hold up. I really don't want to spend money upgrading new tires to another set of new tires.

Understood and agree. I only did it because I lost one tire to a nail and a second to a manufacturing defect (exterior bubble that I saw and 2 interior bubbles that I found after the tire place took the tire off of the wheel). Instead of replacing 2 with OEM tires, I went ahead and bit the bullet for 4 new tires.

[Herk7769]

After my bearing failure, my faith in Marathons have been fully justified, IMO. The tire on the failed wheel was perfect and was reinstalled "as is" and is still going strong 4,000 miles later.

[2012WhiteSolera]

It is extremely unsafe to use car/truck tires for a trailer application, especially where the trailer weight on the tires exceeds the rated capacity. As others have said, the side wall construction is much heavier in a trailer tire, which reduces sway, which means a safer tow, thus the added expense.

[Airdale]

Originally Posted by wmtire

Oakman has really hit the nail on the head, for the biggest reason you shouldn't use passenger tires on trailers..........as well as the other reasons that many members have pointed out (internal construction, chemical composition, etc).

Points to ponder:

1. If passenger designated tires were the answer (and legal), then trailer manufacturers would use them, since they are usually cheaper in price and more readibly available.

2. I stated "legal" above because vehicle and trailer/RV manufacturers must adhere to Federal Motor Vehicle Safety Standards (FMVSS). These standards state what the load capacity has to be for tires mounted on vehicles and trailers/RV's. The tires have to carry what the axles are capable of.

We need to familiarize ourselves with a few parts of the FMVSS, which are the regulations for trailers/RV's under 10,000 pounds GVWR and the ones for trailers/RV's over 10,000 pounds GVWR..................as well as to what tires can meet the specs in the regulations.

Under 10,000 pounds:
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 - Federal Motor Carrier Safety Administration

S4.2.2 Tire load limits for multipurpose passenger vehicles, trucks, buses, and trailers.

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.

Over 10,000 pounds:
Tire selection and rims and motor home/recreation vehicle trailer load carrying capacity information for motor vehicles with a GVWR of more than 4,536 kilograms (10,000 pounds). - Federal Motor Carrier Safety Administration

S2. Purpose. The purpose of this standard is to provide safe operational performance by ensuring that vehicles to which it applies are equipped with tires of adequate size and load rating and with rims of appropriate size and type designation, and by ensuring that consumers are informed of motor home/recreation vehicle trailer load carrying capacity.


S5.1.2 Except in the case of a vehicle which has a speed attainable in 3.2 kilometers of 80 kilometers per hour or less, the sum of the maximum load ratings of the tires fitted to an axle shall be not less than the gross axle weight rating (GAWR) of the axle system as specified on the vehicle's certification label required by 49 CFR part 567. Except in the case of a vehicle which has a speed attainable in 2 miles of 50 mph or less, the sum of the maximum load ratings of the tires fitted to an axle shall be not less than the gross axle weight rating (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. If the size designation of the tires fitted to the axle does not appear on the certification label, the sum shall be not less than the lowest GAWR appearing on the label. When a passenger car tire is installed on a multipurpose passenger vehicle, truck, bus, or trailer, the tire's load rating shall be reduced by dividing by 1.10 before calculating the sum (i.e., the sum of the load ratings of the tires on each axle, when the tires' load carrying capacity at the recommended tire cold inflation pressure is reduced by dividing by 1.10, must be appropriate for the GAWR).

Those are minimum standards for the vehicle manufacturer to follow. When reading them more closely you will find that they tell the manufacturer what to do. Once the manufacturer has set the standard and certified it, the certification label and tire information placard information becomes the minimum standard for owners.

The following quote is a tire industry standard and comes from a well known tire manufacturer. It is what all tire manufacturers expect their chain of retailers to follow.

"The replacement tire must have a maximum load carrying capacity equal to or greater than the maximum load carrying capacity of the original equipment tire. Refer to the tire placard on the vehicle for the recommended inflation pressures of the original equipment size tires. These pressures must be maintained as a minimum."

A

[sidney]

Here's a link to Trailer Tires: Tips & Best Practices

http://www.carlisletransportationpro..._Practices.pdf

There is a lot of good information in the PDF... but keep in mind... Carlisle does not make on road "passenger" tires. Their marketing may be a bit bias and skewed a tad towards selling ST tires.

I agree with the obvious LOAD requirements, i.e. always use tires that meet or exceed the GAWR of the trailer.

I have ST tires on our trailer now... when its time to replace them I may go to an LT tire for a number of reasons.

1. As RKR mentioned... there are numerous accounts of premature catastrophic ST tire failures vs. LT failures.

2. wmtire mentioned cost: "If passenger designated tires were the answer (and legal), then trailer manufacturers would use them, since they are usually cheaper in price and more readibly available."
A good LT tire with a load rating that meets the GAWR of the trailer is considerably more expensive than an ST tire.

In the Cedar Creek line of 5th wheels the heavier models come with G rated LT tires, "8-Lug, LT, “G” Rated, Goodyear Tires on 7000 Axle Units" and is available as an expensive option on the lighter models.

3. Per the link above... the life expectancy of ST tires is 3-5 years regardless of mileage. If ST tires are so superior to LT tires why is there life expectancy so short?

4. Side wall stress... if you understand physics think about the side wall stress of your front steering tires while cornering at typical driving speeds. There is an incredible amount of side wall stress generated when supporting a heavy duty diesel pick up's 5000 lbs of front axle weight while cornering.

5. ST tires are not required to meet the same government safety test standards as passenger tires. Which makes sense... passengers don't ride in trailers.

So far my ST tires are holding up well... but I'm not convinced ST tires are the only way to go.

Happy Holidays

[jlbreaux]

Originally Posted by OldCoot

I wouldn't recommend car tires on a trailer, but my dad took the tires off his 74 Ford LTD and put them on his 1978 24' Coachman and literally towed it from MO to TX to CA to WA to Nova Scotia and back to MO with no problems. I sure wouldn't have tried it, but he was successful doing it.

That LTD probably weighed more than the Coachman! Especially if it was a 4 door. LTD's were the mac daddy of hoopties, although the 72 4 door Impala my parents had was quite the beast also.

[wmtire]

Originally Posted by sidney

2. wmtire mentioned cost: "If passenger designated tires were the answer (and legal), then trailer manufacturers would use them, since they are usually cheaper in price and more readibly available."
A good LT tire with a load rating that meets the GAWR of the trailer is considerably more expensive than an ST tire.

Just want to make sure we are clear on this. A (P) passenger designated tire is not the same as a (LT) designated tire. I think there may be some confusion in the threads, as to this as I see some people referring to LT tires as (P) passenger tires..

You will normally see P designated, LT designated, and ST designated tires........which all have different specs.

[Iwannacamp]

It mostly boils down to price. Most people spend $20K+ on their trailer and want to skimp a $200 on tires. Your families safety is worth more than a few steak dinners or a couple dozen mixed drinks/lattes. IMHO get over it. If you aren't worried about your family...then think about the people behind you.

[jlbreaux]

Originally Posted by wpredock

why not use high mileage car or truck tires on trailers? i can't believe trailer tires don't last any longer than they do. car tires face ten times as much abuse due to heat, cold, high mileage, fowlweather,etc. the tires on my truck have over 65k miles, and are 6 years old . they still have 1/2 of the tread left and the rubber looks as good as new. i have car tires on my flat bed trailer with no problems. it has been all over the mid west and to the east coast. just asking. what am i missing here. bill

Some of the problem with tires are the year they were manufactured. You can buy brand new tires that are 4 years old. Rule of thumb for me is I do not buy tires that are more than 1 year old. Luckily I grew up with the guy where I buy my tires from (Interco), so when I call for tires he knows what I want. I may have to wait for them to come in but so far it has worked out good for me.

On my 20' utility trailer I run D load range (8 ply). I run E load range (10 ply) on my tow vehicle. When I replace the tires on my 5er, yes you guessed it, I will also have E/10 ply tires installed. Layman's term, more weight on tires + more ply's = safer.

[sidney]

Originally Posted by wmtire

Just want to make sure we are clear on this. A (P) passenger designated tire is not the same as a (LT) designated tire. I think there may be some confusion in the threads, as to this as I see some people referring to LT tires as (P) passenger tires..

You will normally see P designated, LT designated, and ST designated tires........which all have different specs.

Good point... but if you read the Carlisle PDF link I provided... they claim you should never use LT tires on your trailer as well as P tires. They are not distinguishing a difference between LT and P tires when considering them for trailer applications. Yet many hi-end 5th wheels come standard with LT tires.

[18CrewDually]

Originally Posted by sidney

Good point... but if you read the Carlisle PDF link I provided... they claim you should never use LT tires on your trailer as well as P tires. They are not distinguishing a difference between LT and P tires when considering them for trailer applications. Yet many hi-end 5th wheels come standard with LT tires.

Of coarse they say that. They don't want to lose sales.