LT225/75R16 on a 2011 Jayco33rlds

[Jay_Flight_33RL]

I posted in another thread my concerns with the ST225/75R15 Goodyear® Marathon Radial on our 2011 Jayco33rlds. I received a lot of good information on different ST tires and some suggestions on upgrading to an LT 16 inch tire. I am willing to spend the money on 16 inch wheels to upgrade to a LT225/75R16. I am looking at Firestone Transforce HT 225/75R16. The specs on the Firestone Transforce HT 225/75R16 indicates that the overall diameter is 29.3 inches. The overall diameter on the ST225/75R15 Goodyear® Marathon Radial is 28.30. Has anyone with a Jayco33rlds done this upgrade and if so what were the results? I truly appreciate the experienced minds that prowl these forums. Thanks for the help.

[stufarmer]

Our Trailer came with cheap a_s Good for a Year 16" tires. I've yet to replace them, but will before our planned big trip. The Wheels are Chrome and are as ugly as they come. Doing my homework, I've decided on Toyo's Open Country Tuff Duty HT's. I've always has excellent performance with my past Toyo's. So I except the same service on the trailer. As for Wheels, hopefully E trailer has fair prices the day my Wife says it's ok.

[Jay_Flight_33RL]

Huntindog wrote:

Jay Flight 33RLDS wrote:

Huntindog wrote:

Jay Flight 33RLDS wrote:

Huntindog wrote:
Do you have 6 lug drums? If so, then that is a great start as 16" rims are most common with 6 lugs. If not, then a swap to 6 lug drums is likely the best solution.

With a diameter difference of only 1", that will only change this measurement by 1/2" over what you have now. So you are probably OK here, though you do need to check it to make sure. If you will not have the necessary clearance, then it can be obtained by a small lift. If the springs are over the axles, then a 1/2" lift block will work.

The other clearance issue is the space between the tires. You need 1" when level. So you will need 2" now in order for the new tires to work. You likely do have this much space. If not, then there is no easy way to solve this issue

Yes, currently have 15" x 6" Rim - 6 lug on 5-1/2.

I'll need to re-check but feel like I have at least 4 inches from the top of the 15 in tire to the inside of the wheel well. . I know I have more than two inches between tires. Where did you get your clearance info?

The clearance info is straight from the Dexter manual.

Just checked. I have 2 1/2 inches clearance from the top of the 15 in tire to the inside of the wheel well and 5 1/2 inches clearance between tires. Doesn't appear like this is going to work without the lift kit you mentioned. I plan to call Jayco Monday to verify. I'll probably end up going the most conservative direction and mount five Maxxis M8008 225/75R15 10ply ST Trailer tires with the expectation I'll need to do it again in about 5 years. Thanks!

2.5" is less than the minimum spec. Was that measure ment the same for all 4 tires?

If so, then you already have a clearance issue. It is possible that you just haven't hit a bump hard enough for the tire to contact the wheelwell,,,,,,yet.

More likely is the measurement wasn't done right.
The axles are constantly moving and shifting in relation to one another. If the equalizer between the springs is not level, then one tire will have more clearance than the other. A simple way to account for this is to measure the clearance od both tires and divide by two.

And... ST tires are considered used up at 3 years.

From Discount Tire:
Time
•Time and the elements weaken a trailer tire.
•In approximately three years, roughly one-third of the tire's strength is gone.
•Three to five years is the projected life of a normal trailer tire.
•It is suggested that trailer tires be replaced after three to four years of service regardless of tread depth or tire appearance.

Yup, same measurement all around, 2 ½ inches. I’m 54 years old and feel like I can run a tape measure pretty good… I’ve towed this baby close to 10,000 miles since May 2011 and there is no indication of contact with the tire inside the wheel well. Everything is at factory defaults. No changes have been made. I do agree with the lack of longevity with ST tires but at this point I am willing to concede that it is what it is and move on to a set Maxxis M8008 225/75R15 10ply ST Trailer tires being mindful of the date code prior to purchasing. I’ll not accept anything more than 6 months old. I do plan to call Jayco for consultation with them on Monday. I’m not interested in a lift kit or altering the suspension in any way. I appreciate anyone’s input and suggestions. Thanks!

[Huntindog]

Jay Flight 33RLDS wrote:

Huntindog wrote:

Jay Flight 33RLDS wrote:

Huntindog wrote:
Do you have 6 lug drums? If so, then that is a great start as 16" rims are most common with 6 lugs. If not, then a swap to 6 lug drums is likely the best solution.

With a diameter difference of only 1", that will only change this measurement by 1/2" over what you have now. So you are probably OK here, though you do need to check it to make sure. If you will not have the necessary clearance, then it can be obtained by a small lift. If the springs are over the axles, then a 1/2" lift block will work.

The other clearance issue is the space between the tires. You need 1" when level. So you will need 2" now in order for the new tires to work. You likely do have this much space. If not, then there is no easy way to solve this issue

Yes, currently have 15" x 6" Rim - 6 lug on 5-1/2.

I'll need to re-check but feel like I have at least 4 inches from the top of the 15 in tire to the inside of the wheel well. . I know I have more than two inches between tires. Where did you get your clearance info?

The clearance info is straight from the Dexter manual.

Just checked. I have 2 1/2 inches clearance from the top of the 15 in tire to the inside of the wheel well and 5 1/2 inches clearance between tires. Doesn't appear like this is going to work without the lift kit you mentioned. I plan to call Jayco Monday to verify. I'll probably end up going the most conservative direction and mount five Maxxis M8008 225/75R15 10ply ST Trailer tires with the expectation I'll need to do it again in about 5 years. Thanks!

2.5" is less than the minimum spec. Was that measure ment the same for all 4 tires?

If so, then you already have a clearance issue. It is possible that you just haven't hit a bump hard enough for the tire to contact the wheelwell,,,,,,yet.

More likely is the measurement wasn't done right.
The axles are constantly moving and shifting in relation to one another. If the equalizer between the springs is not level, then one tire will have more clearance than the other. A simple way to account for this is to measure the clearance od both tires and divide by two.

And... ST tires are considered used up at 3 years.

From Discount Tire:
Time
•Time and the elements weaken a trailer tire.
•In approximately three years, roughly one-third of the tire's strength is gone.
•Three to five years is the projected life of a normal trailer tire.
•It is suggested that trailer tires be replaced after three to four years of service regardless of tread depth or tire appearance.

[travelnutz]

Jay Flight 33RLDS,

Now you're cooking!

Maxxis 15" 10 ply or equivalent with their higher PSI inflation and higher load carrying capacity rating. Not a big deal to put 1/2" to 1" spacers in to acheive a little more clearance if so desired. Another way is to put 4 rubber bumpers in the virtually stop the axle from going the final 1/2" for the tires to hit the wheelwell inner. The rubber bumpers cushion so there is no hard hammering effect. Jayco frames can take their use. Try driving a 16P nail with a rubber hammer and then switch to a steel hammer and see what happens. You'll answer your own questions!

However, I wouldn't advise doing it with Lippert frames as so many have had real issues, flexing, and failures. Constant frame flexing usually results in propagating cracking and fracturing of the steel rails and/or weld joints at high stress points.

[Jay_Flight_33RL]

Huntindog wrote:

Jay Flight 33RLDS wrote:

Huntindog wrote:
Do you have 6 lug drums? If so, then that is a great start as 16" rims are most common with 6 lugs. If not, then a swap to 6 lug drums is likely the best solution.

With a diameter difference of only 1", that will only change this measurement by 1/2" over what you have now. So you are probably OK here, though you do need to check it to make sure. If you will not have the necessary clearance, then it can be obtained by a small lift. If the springs are over the axles, then a 1/2" lift block will work.

The other clearance issue is the space between the tires. You need 1" when level. So you will need 2" now in order for the new tires to work. You likely do have this much space. If not, then there is no easy way to solve this issue

Yes, currently have 15" x 6" Rim - 6 lug on 5-1/2.

I'll need to re-check but feel like I have at least 4 inches from the top of the 15 in tire to the inside of the wheel well. . I know I have more than two inches between tires. Where did you get your clearance info?

The clearance info is straight from the Dexter manual.

Just checked. I have 2 1/2 inches clearance from the top of the 15 in tire to the inside of the wheel well and 5 1/2 inches clearance between tires. Doesn't appear like this is going to work without the lift kit you mentioned. I plan to call Jayco Monday to verify. I'll probably end up going the most conservative direction and mount five Maxxis M8008 225/75R15 10ply ST Trailer tires with the expectation I'll need to do it again in about 5 years. Thanks!

[Huntindog]

Jay Flight 33RLDS wrote:

Huntindog wrote:
Do you have 6 lug drums? If so, then that is a great start as 16" rims are most common with 6 lugs. If not, then a swap to 6 lug drums is likely the best solution.

With a diameter difference of only 1", that will only change this measurement by 1/2" over what you have now. So you are probably OK here, though you do need to check it to make sure. If you will not have the necessary clearance, then it can be obtained by a small lift. If the springs are over the axles, then a 1/2" lift block will work.

The other clearance issue is the space between the tires. You need 1" when level. So you will need 2" now in order for the new tires to work. You likely do have this much space. If not, then there is no easy way to solve this issue

Yes, currently have 15" x 6" Rim - 6 lug on 5-1/2.

I'll need to re-check but feel like I have at least 4 inches from the top of the 15 in tire to the inside of the wheel well. . I know I have more than two inches between tires. Where did you get your clearance info?

The clearance info is straight from the Dexter manual.

[Keith099]

It's not just the weight rating you need to consider. It's the "weight at speed" rating. It's a measure of how much sidewall stress the tire can withstand. You should never exceed either value.

ST225/75R15 D is 2540lbs at 65mph.
LT225/75R16 115/112R E is 2680lbs at 106mph

Michelin LTX M/S2's will roll easier, wear longer, and have better braking than the LE2's. Either one, you can't go wrong.

As for fit, there's zero chance that an extra 0.5" radius will create clearance problems. You will, however, very likely need to adjust your hitch for proper weight distribution and sway control. TT sitting 1/2" higher will take tension off.

[Jay_Flight_33RL]

Huntindog wrote:
Do you have 6 lug drums? If so, then that is a great start as 16" rims are most common with 6 lugs. If not, then a swap to 6 lug drums is likely the best solution.

With a diameter difference of only 1", that will only change this measurement by 1/2" over what you have now. So you are probably OK here, though you do need to check it to make sure. If you will not have the necessary clearance, then it can be obtained by a small lift. If the springs are over the axles, then a 1/2" lift block will work.

The other clearance issue is the space between the tires. You need 1" when level. So you will need 2" now in order for the new tires to work. You likely do have this much space. If not, then there is no easy way to solve this issue

Yes, currently have 15" x 6" Rim - 6 lug on 5-1/2.

I'll need to re-check but feel like I have at least 4 inches from the top of the 15 in tire to the inside of the wheel well. . I know I have more than two inches between tires. Where did you get your clearance info?

[Huntindog]

Jay Flight 33RLDS wrote:
I posted in another thread my concerns with the ST225/75R15 Goodyear® Marathon Radial on our 2011 Jayco33rlds. I received a lot of good information on different ST tires and some suggestions on upgrading to an LT 16 inch tire. I am willing to spend the money on 16 inch wheels to upgrade to a LT225/75R16. I am looking at Firestone Transforce HT 225/75R16. The specs on the Firestone Transforce HT 225/75R16 indicates that the overall diameter is 29.3 inches. The overall diameter on the ST225/75R15 Goodyear® Marathon Radial is 28.30. Has anyone with a Jayco33rlds done this upgrade and if so what were the results? I truly appreciate the experienced minds that prowl these forums. Thanks for the help.

I have no experience with your TT. But I have upgraded tires on all of my TTs.

Some are eaiser than others to do.

Do you have 6 lug drums? If so, then that is a great start as 16" rims are most common with 6 lugs. If not, then a swap to 6 lug drums is likely the best solution.

The tire diameter is a concern in two areas. The clearance from the top of the tire to the wheelwell. It needs to be 3" or more. Measured when the TT spring equalizer is level.
With a diameter difference of only 1", that will only change this measurement by 1/2" over what you have now. So you are probably OK here, though you do need to check it to make sure. If you will not have the necessary clearance, then it can be obtained by a small lift. If the springs are over the axles, then a 1/2" lift block will work.

The other clearance issue is the space between the tires. You need 1" when level. So you will need 2" now in order for the new tires to work. You likely do have this much space. If not, then there is no easy way to solve this issue.

16" tires are a great upgrade, as it opens up a vast choice of quality tires to you. Due to the fact that many pickups take this size, it is one of the most common sizes available.

[Huntindog]

rbpru wrote:
I guess the question is how much safer is safer?

My TT axels are rated to 3500 lbs. each or 1750 lbs. per tire, my OEM ST205/75R15 tires are rated 1820 lbs. load range C. A safety margin of 70 lbs. per tire.

When it comes time to change I will probably go to a slightly larger ST225/75R15 load range C rated 2150 lbs. per tire, providing a safety factor of 400 lbs. per tire. If there is enough clearance for the wider tire I can use the same rims.

I could go to a D rated tire and get a 790 lb. safety factor per tire but where do you draw the line? Heck there are some E rated tire that would darn near allow me to go to a single axle.

I have put 10,000 plus miles on the OEM tire and I bought the rig used. The tires will time out before they wear out and the ST225s are about the same price as the ST205s. I only hope they will ride as smooth.

One thing to consider is that the tire rating is for a new tire. As the tire ages, it will become less and less able to perform as designed. Of course that is true of most all of the running gear, but axles, bearings etc. degrade much slower over time than rubber.... So starting with a substantial margin in a tire is a good thing.

How much is debatable.... I like to get as much as is reasonably possible YMMV.

[rbpru]

I guess the question is how much safer is safer?

My TT axels are rated to 3500 lbs. each or 1750 lbs. per tire, my OEM ST205/75R15 tires are rated 1820 lbs. load range C. A safety margin of 70 lbs. per tire.

When it comes time to change I will probably go to a slightly larger ST225/75R15 load range C rated 2150 lbs. per tire, providing a safety factor of 400 lbs. per tire. If there is enough clearance for the wider tire I can use the same rims.

I could go to a D rated tire and get a 790 lb. safety factor per tire but where do you draw the line? Heck there are some E rated tire that would darn near allow me to go to a single axle.

I have put 10,000 plus miles on the OEM tire and I bought the rig used. The tires will time out before they wear out and the ST225s are about the same price as the ST205s. I only hope they will ride as smooth.

[donn0128]

Check some other brand specs. Not all tire diameters are the same.

[travelnutz]

Jay Flight 33RLDS,

I suggest that it is not the difference between 15" and 16" that gives you added tire capacity so you are not running at close to 100% of your OEM tire's rating at max pressure. Is the difference between "D" range and "E" range rating of max capacity at max pressure. The added 2 extra ply ratings on the "E" tire and allowing an additional 15 psi of inflation.

225/75/15 "D" (8 ply rated) has a max capacity of 2540 lbs at 65 psi per tire. While a 225/75/15 "E" (10 ply rated) has a max capacity of 2830 lbs at 80 psi per tire. + 290 lbs per tire or 1160 for the 4 tires. A 225/75/15 "D" tire at max pressure being at 100% of weight capacity is only at 90% of capacity with a 225/75/15 "E" tire at max pressure and has the same OD as the 225/75/16 tire.

This means you'd be accomplishing your same desire but not having to replace the wheels. Just the tires. This is exactly what I had done on my RV and it works great and so much less heat buildup in the tires which will quickly compromise the tire's structure components and lessen their useful life. Blowouts aren't any fun! I use my infrared temp gauge and saw an average of approx 17 degrees less tire sidewall heat buildup with the "E"s on our trailer in 2 years of constantly checking them each time we'd stop in a rest area etc when traveling. The sun side is usually always 10-15 degrees hotter than the shaded side of an RV so keeping them cooler when traveling the road is very important.

[Need-A-Vacation]

Mark,

Keep us posted on what your find out about this tire size swap please. Wondering the same thing about our new 32 BHDS.

May need to take the trailer to your local tire shop and have them do a test fit to see how much clearance you have.

Good luck!!!