Wanting to change from STs to LTs..........

[Paulb1310]

We are the proud new owners of a 2007 K-Z Sportsman 5th wheel. The unit is in EXCELLENT shape for its age. This is our first (but likely won't be our last).

I have read numerous posts on the arguments of STs versus LTs. My conclusion is the I am going to replace the current tires/wheels with larger, more robust ones.

Here is what I currently have:
Tire: Load Max Radial
Tire Size: ST225/75R15
Overall diameter: 28.3"
Rim width range: 6-7"
Date Code: 614 0906 (waaaaay old!)
Wheels: Six bolt on 5.5" centers
Load rating for each tire: 2540 pounds
GVWR for trailer: 10,000 pounds

Here is what I want:
Tire: Michelin LTX A/T 2
Tire Size: LT245/75R16
Rim width range: 6.5-8"
Overall diameter: 30.5"

Wheel Choice #1: HiSpec Series 04
Wheel Size: 16x7
Wheel load rating: 3200
Offset: +5mm

Wheel Choice #2: HiSpec Series 05
Wheel Size: 16x6.5
Wheel load rating: 3580 pounds
Offset: 0mm

So, what have I considered so far?

1. Separation between current tires is 5.0". By using this size tire the separation would be 2.8". This would appear to be sufficient.

2. Currently there is 6" of suspension travel between the top of the tire and the floor of the 5th wheel. This would be reduced to 4.9". This, too, seems sufficient.

3. The passenger side shocks currently sit 3/4" away from the tire. This might be dicey with a bigger tire and wheel. If the tire is too close the options are to (a) put a spacer between the wheel and the hub with longer lug nuts or (b) move the shock to the other side of the axle (likely NOT a good option.)

4. The passenger side front tire is close to the fender. I could (a) trim off part of the fender or (b) install a brace underneath to push the fender our a few tenths of an inch or (c) a combination of (a) and (b).

5. The top of the tire to the bottom of the fender is 3.5". I don't know just how much more the bigger tires would protrude. Of course, the current tires don't have a problem with hitting the inside edge of the fender. I'm not sure if the bigger tires would have an issue or not.

So, what have I missed?


Thanks for your help!!

Paul.

[Me_Again]

Bamaman1 wrote:
I just picked up a set of R250's to replace the Chinese Will Pops on my new fifth wheel trailer. They were $195 @ Costco with $70 Bridgestone rebate.

I cannot get over how heavy these ribbed tires are. They're 1" thick rubber, and solid steel cores bead to bead. And they're well over 50 lbs. each.

R250's are tires you see on F450 trucks with utility bodies and cranes--service trucks. They're too beefy to use on a common every day 3/4 ton truck.

The guy at Costco says he's seen'em get 100K miles, and they've had absolutely no problems with the tires. I'm sold on them for RV use--especially at the price.

I have had R250 on the trailer for 2 years and just ordered via Costco BS Duravis R500 HD for the pickup. Chris

[Bamaman11]

I just picked up a set of R250's to replace the Chinese Will Pops on my new fifth wheel trailer. They were $195 @ Costco with $70 Bridgestone rebate.

I cannot get over how heavy these ribbed tires are. They're 1" thick rubber, and solid steel cores bead to bead. And they're well over 50 lbs. each.

R250's are tires you see on F450 trucks with utility bodies and cranes--service trucks. They're too beefy to use on a common every day 3/4 ton truck.

The guy at Costco says he's seen'em get 100K miles, and they've had absolutely no problems with the tires. I'm sold on them for RV use--especially at the price.

[gitane59]

AH64ID wrote:

Me Again wrote:
Half the people that post here about good results with Marathons do not even own a 5th! Maybe they are just 5th wheel want to bees! Chris

As stated for the same GVWR the 5er will have lower axle weights than a TT... not sure how that is harder on a set of tires???

Anything useful to add other than banter?

I don't think you are going to find too many 14K-16K lb TT's out there. Now your logic is correct but the 5er will need to be very small. Bottom line try putting Marathons on any type of trailer, boat trailer, horse trailer, travel trailer, utility trailer, fifthwheel trailer with equal weight on the axles and be very scared.
Anyone rolling on Marathons is rolling on borrowed time.

[P_Kennedy]

Me Again remember it is easier to complain and get attention here than spend the money and know the truth. Ain't no ST tires on this rig and wondering if the tires were maxed out was not a question. 65-70 mph, 500 miles and no disasters. This trailer gets 5 times the abuse any one RV 5th wheel every day, rough roads, heavy loads, turning at 90+, hot & cold. Just for the "you can't haul that load folks" that is 100% loaded legal in Alberta weight wise as per tire, axle and gross okey dokey.

[larry_barnhart]

Me Again wrote:

ah64id wrote:


When used in their parameters they work, when taken outside of them they don't.

True ST tires were designed as a cheap solution for local service on utility type trailers and were not intended for freeway speeds for extended periods. With little changes they now are standard fair on RV trailers.

Which tire would I trust to do the 1650 mile trip from NW Washinton to the East Valley in 3.5 days.

A. 35 Pound poly carcass Marathon
B. 59 Pound steel carcass R250

Which of the above would have one constantly watching their mirrors.

Chris

This has been my response when asked about tires . The weight does not seem to matter and then I am done with them. One couple did get the bridge stones R250 because they did understand what I was telling them. One out of????

chevman

[Me_Again]

ah64id wrote:


When used in their parameters they work, when taken outside of them they don't.

True ST tires were designed as a cheap solution for local service on utility type trailers and were not intended for freeway speeds for extended periods. With little changes they now are standard fair on RV trailers.

Which tire would I trust to do the 1650 mile trip from NW Washinton to the East Valley in 3.5 days.

A. 35 Pound poly carcass Marathon
B. 59 Pound steel carcass R250

Which of the above would have one constantly watching their mirrors.

Chris

[Me_Again]

ah64id wrote:
Some issues are valid, some are mute and poor manufacturer design.

Heavier isn't an issue if the proper components are used.

The tight scrubbing is an argument for ST over LT...

Proper parts for the job. Anything at 98% of it's rating is more susceptible to failure than the same component at 80%.

Manufacturers are putting the owners in a tight spot, proper components would go a long ways.

Very few people check tire pressures, nor do they obey speed ratings. Both of which induce premature failure, as you know. Most those people will claim they don't exceed ratings and they check their tires, but that's more of today's blame game than reality.

Lot of ST coolaid in your post above! Enjoy!

[AH64ID]

Some issues are valid, some are mute and poor manufacturer design.

Heavier isn't an issue if the proper components are used.

The tight scrubbing is an argument for ST over LT...

Proper parts for the job. Anything at 98% of it's rating is more susceptible to failure than the same component at 80%.

Manufacturers are putting the owners in a tight spot, proper components would go a long ways.

Very few people check tire pressures, nor do they obey speed ratings. Both of which induce premature failure, as you know. Most those people will claim they don't exceed ratings and they check their tires, but that's more of today's blame game than reality.

[Me_Again]

ah64id wrote:

Me Again wrote:
Half the people that post here about good results with Marathons do not even own a 5th! Maybe they are just 5th wheel want to bees! Chris

As stated for the same GVWR the 5er will have lower axle weights than a TT... not sure how that is harder on a set of tires???

Anything useful to add other than banter?

Yes!

5th wheels are much taller and therefore can put more temporary loading on tires.

5th wheels can be jack knifed much sharper putting tires in extreme positions.

3rd 5th wheels are general much heavier.

4th related to 3 above, 5th wheels have much more storage space thus tend to get heavily loaded. Think "snowbird"!

5th many 5th wheel manufacturers are building 5th wheel that max out ST235/80R16E tires, which is our primary complaint.

6th ST tires are cheaply made, carry inflated weight rates that are not realistic for freeway use at max rating.

When a major manufacturer like Keystone derates 7k axles to 6750 to be able is install tires rated to 3420, that leaves 90 lbs of excess capacity. At trailer can easily be out of balance left to right way more than that.

Drive the 300 miles from Palm Springs to Phoenix with 40 MPH wind out of the South all day and see how much extra load and heat build up is on the down wind tires. I have done this several times!

Now tell us about your experience with these issues and conditions!

Chris

[AH64ID]

Me Again wrote:
Half the people that post here about good results with Marathons do not even own a 5th! Maybe they are just 5th wheel want to bees! Chris

As stated for the same GVWR the 5er will have lower axle weights than a TT... not sure how that is harder on a set of tires???

Anything useful to add other than banter?

[Me_Again]

Half the people that post here about good results with Marathons do not even own a 5th! Maybe they are just 5th wheel want to bees! Chris

[ol_Bombero-JC]

ah64id wrote:

ol Bombero-JC wrote:

GY made that one disappear - although it still can be found out there in cyberspace.



~

When was that? I have a press release form January of this year.

Excellent.

Link it !! (make sure it has a date & source) -
bet lots of Marathon ST tire owners would like to have it in hand when they contact GY for replacement tires - and repairs to their trailers!

Be good to do the same on the Marathon Failure thread on the Air Forums!

(And be ready to dodge the flak) ROTFL.

~

[JIMNLIN]

Michelin publishes a guide of tire pressures based on tire load. (This is linked somewhere else in this thread.) At the loading I will be placing on these tires, I will likely run 50-55 PSI.

IMO not the best idea for tire pressures on a trailer with 80 psi tires. Works great on other RV types.

Experienced trailer owners and many tire experts and our oldest trailer tire makers that understand trailer tire (P/ST or LT) issues use or recommend max sidewall pressures.
Now if the trailer owner has over tired the trailer above say 15-20 reserve percent above axle ratings then at some point max pressures isn't the best idea.

Tireman9 .....one of our tire engineers also recommends max sidewall pressures says; from rvtiresafety.com his online tire blog;

"The manufacturers do not take into consideration the side to side unbalance, as to do so would require them to provide larger (more expensive) tires. The other thing RV industry does not take into consideration is the forces to the tire structure due to running close axle spacing. Engineering analysis shows that when turning corners the forces trying to tear the tire apart can be over 20% higher in multi-axle applications than with tires at the corners of the vehicle.
The only options for the trailer owner are to up-size the tires (if there is room) or up-rate and increase inflation (if a higher Load Range tire and stronger wheels are available). Lacking the above being sure to run the tire at the inflation shown on the sidewall (i.e. max) will slightly decrease but not eliminate the overload forces.
...................................................................

RVsafety.com says;
Travel Trailer/ 5th Wheel owners Due to the severe use conditions experienced by tires when axles are very close together – tire industry experts recommend maximum (sidewall) inflation pressure for towable tires unless this causes a severe over-inflation situation (20psi+), often referred to as the ‘basketball effect’. If this is your situation allow a 10 – 15psi safety margin above the minimum required inflation pressure.
...................................................................

Goodyear website weighing a RV says this;
Special Considerations
Unless trying to resolve poor ride quality problems with an RV trailer, it is recommended that trailer tires be inflated to the pressure indicated on the sidewall of the tire. Trailer tires experience significant lateral (side-to-side) loads due to vehicle sway from uneven roads or passing vehicles. Using the inflation pressure engraved on the sidewall will provide optimum load carrying capacity and minimize heat build-up.

Sorry for the long post but when it comes to best tire pressure for tires on a trailer its important to use the best pressure for best long term reliability.

[AH64ID]

ol Bombero-JC wrote:

GY made that one disappear - although it still can be found out there in cyberspace.



~

When was that? I have a press release form January of this year.