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

Paulb1310
Explorer
Explorer
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.
78 REPLIES 78

Me_Again
Explorer II
Explorer II
Charlie D. wrote:
camperkilgore wrote:
Beginning to wonder about the wisdom of using more expensive LT tires. I did the same thing after losing tires to blowouts. The original tires on our fiver were the Chinese made tires, so I went from 15" to 16" tires and switched to BFG commercial TA tires. We made three trips to western states from Florida with no problems, but three years later, lost the tread on one and discovered another had problems with separation and was ready to go at any time.

So at this point I'm beginning to think that it might(MIGHT) be better to go with ST tires with stiffer sidewalls, but make sure that I replace them every 2 1/2 to 3 years. Being proactive about it might prevent a lot of aggravation down the road. Being able to locate the best deal when replacing all four would be better than getting stuck with a bad deal when out in the boonies some where.

This is a plan that would probably make the most sense for me based on my particular camper and my experiences with that camper. Your mileage may vary.


I had the exact same problems with BFG T/A's. There seems to be more and more posts about their failures.


It's cousin the Uniroyal Laredo HT/H did the same thing on HH2's at around 5 years old when used near it's max rating. Go Steelers! (Ribs or R250s), just say no to poly! Of course I have a friend that lost a TA in Arizona at around two years.

Chris
2021 F150 2.7 Ecoboost - Summer Home 2017 Bighorn 3575el. Can Am Spyder RT-L Chrome, Kawasaki KRX1000. Retired and enjoying it! RIP DW 07-05-2021

Charlie_D_
Explorer
Explorer
camperkilgore wrote:
Beginning to wonder about the wisdom of using more expensive LT tires. I did the same thing after losing tires to blowouts. The original tires on our fiver were the Chinese made tires, so I went from 15" to 16" tires and switched to BFG commercial TA tires. We made three trips to western states from Florida with no problems, but three years later, lost the tread on one and discovered another had problems with separation and was ready to go at any time.

So at this point I'm beginning to think that it might(MIGHT) be better to go with ST tires with stiffer sidewalls, but make sure that I replace them every 2 1/2 to 3 years. Being proactive about it might prevent a lot of aggravation down the road. Being able to locate the best deal when replacing all four would be better than getting stuck with a bad deal when out in the boonies some where.

This is a plan that would probably make the most sense for me based on my particular camper and my experiences with that camper. Your mileage may vary.


I had the exact same problems with BFG T/A's. There seems to be more and more posts about their failures.
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Native Texan
2013 Prime Time Crusader 330MKS
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hone_eagle
Explorer
Explorer
camperkilgore wrote:
Beginning to wonder about the wisdom of using more expensive LT tires. I did the same thing after losing tires to blowouts. The original tires on our fiver were the Chinese made tires, so I went from 15" to 16" tires and switched to BFG commercial TA tires. We made three trips to western states from Florida with no problems, but three years later, lost the tread on one and discovered another had problems with separation and was ready to go at any time.

So at this point I'm beginning to think that it might(MIGHT) be better to go with ST tires with stiffer sidewalls, but make sure that I replace them every 2 1/2 to 3 years. Being proactive about it might prevent a lot of aggravation down the road. Being able to locate the best deal when replacing all four would be better than getting stuck with a bad deal when out in the boonies some where.

This is a plan that would probably make the most sense for me based on my particular camper and my experiences with that camper. Your mileage may vary.


And if one blows ?
Damage can run into several $$$$.
Remember cry a little now when you buy them , or cry rivers later.
2005 Volvo 670 singled freedomline 12 speed
Newmar 34rsks 2008
Hensley trailersaver TSLB2H
directlink brake controller

-when overkill is cheaper-

Me_Again
Explorer II
Explorer II
camperkilgore wrote:
Beginning to wonder about the wisdom of using more expensive LT tires. I did the same thing after losing tires to blowouts. The original tires on our fiver were the Chinese made tires, so I went from 15" to 16" tires and switched to BFG commercial TA tires. We made three trips to western states from Florida with no problems, but three years later, lost the tread on one and discovered another had problems with separation and was ready to go at any time.

So at this point I'm beginning to think that it might(MIGHT) be better to go with ST tires with stiffer sidewalls, but make sure that I replace them every 2 1/2 to 3 years. Being proactive about it might prevent a lot of aggravation down the road. Being able to locate the best deal when replacing all four would be better than getting stuck with a bad deal when out in the boonies some where.

This is a plan that would probably make the most sense for me based on my particular camper and my experiences with that camper. Your mileage may vary.


ST tires do not have stiffer side walls vs most LT tires.

If you are keeping the trailer for many years then XPS RIBs or R250s will be cheaper in the long run with 6 to 8 years of use, then sell them on CL. I got $200 for four 6.5 year old RIBs.

No other tire comes close to one of these two on 5200 or 6000 axles. I have used both. We do the 1650 miles between NW Washington and Arizona in 3.5 days and never worry about tires. Nice thing is our trailer placard list LT235/85R16E, so the eagle and tire companies can not play their games with us.

Chris
2021 F150 2.7 Ecoboost - Summer Home 2017 Bighorn 3575el. Can Am Spyder RT-L Chrome, Kawasaki KRX1000. Retired and enjoying it! RIP DW 07-05-2021

camperkilgore
Explorer
Explorer
Beginning to wonder about the wisdom of using more expensive LT tires. I did the same thing after losing tires to blowouts. The original tires on our fiver were the Chinese made tires, so I went from 15" to 16" tires and switched to BFG commercial TA tires. We made three trips to western states from Florida with no problems, but three years later, lost the tread on one and discovered another had problems with separation and was ready to go at any time.

So at this point I'm beginning to think that it might(MIGHT) be better to go with ST tires with stiffer sidewalls, but make sure that I replace them every 2 1/2 to 3 years. Being proactive about it might prevent a lot of aggravation down the road. Being able to locate the best deal when replacing all four would be better than getting stuck with a bad deal when out in the boonies some where.

This is a plan that would probably make the most sense for me based on my particular camper and my experiences with that camper. Your mileage may vary.
Tom & Carol

shadows4
Explorer III
Explorer III
I have the Maxxis in an E rated 225/75R15. Very happy with them so far, been 2 1/2 years and about 10-12,000 miles. 5er is just under 10,000 lbs. Good luck, John
2016 4X4 F350,CC,SB,Lariat,6.7L diesel,
2015 Coachmen Chapparal 324 TSRK
B&W Patriot 16K hitch.

Bamaman11
Explorer
Explorer
Me Again wrote:
R250 = $250 not $550?


Excuse me--that's for a pair. Seem like really good tires, however. TireRack.com has them for $232 each.

MC9
Explorer
Explorer
TransForce for me and made in the same Canadian factory as my Duravis on the TV.

laknox
Nomad
Nomad
bobx2 wrote:
Several E rated tires available in a 15" size. I upgraded to a set of E rated Carlisles 225-75-15. My 5th wheel grosses the same as yours at 9,999 lbs. Plenty of extra capacity for a safety margin now. Need to be sure your wheels are rated for 80 psi if you want the benefits from the E rating.


I also have the Carlisles in E rating. So far (touch wood) they're holding up.

Lyle
2022 GMC Sierra 3500 HD Denali Crew Cab 4x4 Duramax
B&W OEM Companion & Gooseneck Kit
2017 KZ Durango 1500 D277RLT
1936 John Deere Model A
International Flying Farmers 64 Year Member

laknox
Nomad
Nomad
bpounds wrote:
My question would be, what size and weight is your KZ Sportsman. Looking at the current specs, the largest fiver in that series is only a GVWR 8,800lbs trailer.

Assuming yours is of similar size, you've got plenty of tire in an ST 225/75-15 LRD. Four of those would have a rating of a bit over 10k, and an 8,800lb trailer would only ride about 6k - 7k lbs on the tires.

You are new here, and you've read all the horror stories about ST tires, but you may be missing the fact that those failures are common on big trailers where the manufacturer has spec'd tires that barely squeak over the GVWR of the trailer. Plus the fact that we've got some really noisy ST haters around here.

I suspect you're throwing a lot of money at a problem that doesn't exist. At most you could consider going up to an E rated tire in the same size, and probably only pay around $25 total extra for all four over the D rated.

On Edit: I see now where you noted the GVWR is 10k. So a little more than their current product line. Still a light trailer, and my advice doesn't change. At most you'll be running at 80% of LRD tire rating, and it would be even a lower percent on LRE tires.


My Komfort has a GVW of 11,300 lbs and came with D's. I upgraded to E's and feel much better. I always run at 80 psi unless I'm =really= light, then drop to 70.

Lyle
2022 GMC Sierra 3500 HD Denali Crew Cab 4x4 Duramax
B&W OEM Companion & Gooseneck Kit
2017 KZ Durango 1500 D277RLT
1936 John Deere Model A
International Flying Farmers 64 Year Member

FastEagle
Explorer
Explorer
JIMNLIN wrote:
Paulb1310 wrote:
Jimnlin:

Thanks for the input. I will research each of those tires. Do you have first hand experience with any of these tires?

Does anybody else have first hand experience with any of these tires in this list?

Just saw your question.
The tires on the list have been used for years on trailers of all type including RVs. You asked for recommendations and these are some of the more popular brands that the tire maker has recommended and come with a full warranty.

I've personally have used and currently using the BFG Commercials and the Firestone Transforce HT.
I've also used the Goodyear Wrangler some years ago on a 21k equipment trailer.


It is often very difficult to find LT tires to replace ST tires because of the disparity in load capacity. The tire industry as a whole doesnโ€™t recommend or warranty replacement tires with less load capacity than the OE tires.

In this reference, Goodyear is very specific in wording about replacement tire load capacity.

Click Here



FastEagle

JIMNLIN
Explorer
Explorer
Paulb1310 wrote:
Jimnlin:

Thanks for the input. I will research each of those tires. Do you have first hand experience with any of these tires?

Does anybody else have first hand experience with any of these tires in this list?

Just saw your question.
The tires on the list have been used for years on trailers of all type including RVs. You asked for recommendations and these are some of the more popular brands that the tire maker has recommended and come with a full warranty.

I've personally have used and currently using the BFG Commercials and the Firestone Transforce HT.
I've also used the Goodyear Wrangler some years ago on a 21k equipment trailer.
"good judgment comes from experience, and a lot of that comes from bad judgment" ............ Will Rogers

'03 2500 QC Dodge/Cummins HO 3.73 6 speed manual Jacobs Westach
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Me_Again
Explorer II
Explorer II
R250 = $250 not $550?
2021 F150 2.7 Ecoboost - Summer Home 2017 Bighorn 3575el. Can Am Spyder RT-L Chrome, Kawasaki KRX1000. Retired and enjoying it! RIP DW 07-05-2021

Bamaman11
Explorer
Explorer
I too have been looking to replace tires on day one--new fifth wheel. These are the prices I've come up with on 16" tires. Most prices are from TireRack, TreadDepot and DiscountTireDirect.com

Bridgestone Duramis R250 $550 a pair
Cooper Discoverer Maxx $198
Maxxis M8008 $160
BFG Commercial T/A $168
Michelin XPS Ribs $285 not including delivery
Goodyear G614-RST $399
Firestone Transforce $170

That's a pretty wide variance in prices, but all tires appear to be acceptable in quality for a fifth wheel trailer. The Maxxis are ST tires, and I read nice things about them.

FastEagle
Explorer
Explorer
If youโ€™re going to use LT tires as replacements maybe you should stick to a more narrow tire with a little more load capacity than you already have. Here is a reference for something more practical. Other manufacturers build this sized tire.

Notice in the reference that the measuring rim was 6โ€. That means all the dimensions are figured on that fitment. As others have noted, zero off-set is required for RV trailer fitments.

Click Here!


FastEagle