Larger Tires on Class C

[Trouttales]

I currently have 225 75 R16 80 psi tires on my class c and have experienced several blow outs. Is there a way to put 235 85 R16 125 psi? Wondering about spacers for the back dual tires with new longer lug bolts. Has anyone done this in the past? What type of spacers would you use?
Thank you.

 

[RRR]

Couple of questions. How is the inflation pressure, How old are the tires and have you checked your axle weights?

 

[CharlesinGA]

This question crops up over and over. There are hundreds or thousands of RV's running around with the same size tire with no issues. You really need to weigh the RV as you keep it loaded, and consider going to Euro "C" tires which are "cargo" or "commercial" tires. They are not classified as Light truck, so they do not have LT preceding the size, but do have a C at the end of the size (and this is NOT related to load ranges) A standard LT225/75R16 tire has a load capacity of 2680 lbs vs a Commercial tire, 225/75R16C of 3195 lbs.

This is one example, Continental Vanco

Here is the Specs for the Toyo H08 tire in the LT version and the Commercial version

TIRE SIZE	PRODUCT CODE	LOAD / SPEED	LOAD ID	SIDEWALL	APPROVED RIM WIDTH RANGE (IN.)	TREAD DEPTH (1/32")	WEIGHT (LBS.)	INFLATED OVERALL DIAMETER (IN.)	INFLATED OVERALL WIDTH (IN.)	MAX LOAD (LBS.)	MAX PRESSURE (PSI)	UTQG	REVS PER MILE
LT225/75R16	369700	115R	E	B	6.0-7.5	14.1	39 lbs.	29.3	8.8	2680	80	-	709
225/75R16C	369750	121R	E	B	6.0-7.0	13.0	36 lbs.	29.3	8.8	3197	83	-	709

Pretty much the same for the Toyo Celsius Cargo tire

TIRE SIZE	PRODUCT CODE	LOAD / SPEED	LOAD ID	SIDEWALL	APPROVED RIM WIDTH RANGE (IN.)	TREAD DEPTH (1/32")	WEIGHT (LBS.)	INFLATED OVERALL DIAMETER (IN.)	INFLATED OVERALL WIDTH (IN.)	MAX LOAD (LBS.)	MAX PRESSURE (PSI)	UTQG	REVS PER MILE
225/75R16C	238470	121R	E	B	6.0-7.0	13.1	36 lbs.	29.3	8.8	3195	83	-	709
LT225/75R16	238490	115R	E	B	6.0-7.5	14.1	38 lbs.	29.3	8.8	2680	80	-	709

Goodyear's version of the C type

Charles

 

[Trouttales]

Couple of questions. How is the inflation pressure, How old are the tires and have you checked your axle weights?

225 is currently 80 psi, tires are about 3 years old. Don't know the axle weight. I was told my RV was max for the 225 75 R16 and to make sure I keep the tires at 80 psi. I was trying to figure out how to increase the tires to a 14 or 16 ply to avoid blow out.

 

[LarsMac]

I would agree with RRR and recommend more investigation into why you've had multiple blowouts.
What are the date codes on the remaining tires? And what is your gross weight and Axle weights when traveling. What pressures have you been running?
If you don't really know what is causing the blowouts, you won't really know what to do to fix the problem.

 

[HueyPilotVN]

On my trip to and from MN I blew out two brand new inside dual tires. The issue according to the guys at discount tire is potholes. The side walls were total ripped out.

Fortunately the outer duel in each case held and I could make it to a place to fix it.

My situation was probably also due to having to much rear weight.

We really need to address the condition of our Interstate Highways.

 

[Onyrlef]

225 is currently 80 psi, tires are about 3 years old. Don't know the axle weight. I was told my RV was max for the 225 75 R16 and to make sure I keep the tires at 80 psi. I was trying to figure out how to increase the tires to a 14 or 16 ply to avoid blow out.

There's part of your problem, who told you and how do they know what your MH weighs? Weigh it when fully loaded out at any CAT scale first, and set your psi according with the tire mfg's table. You won't be able to get a four corner at a CAT scale so set both axle ends to the prescribed RRaxle weight on your ticket. You can go up in psi to the max on the sidewall but never below the psi prescribed in the table. Make certain as well the duals aren't touching, 1/4"-1/2" spacing while under full load is sufficient.

 

[Gary RV_Wizard]

Agree strongly with the others - you need to get the weight facts before deciding wider tires are the answer. And if it turns out the tires are overloaded, consider reducing the load rather than increasing the tire capacity.

A taller & wider tire like the 235/86R16 runs the risk of interference with the wheel well (front tires) or each other (dual wheels). You will need measurements for that too. Start by crawling underneath enough to eyeball the gap between the duals at the closest point (the bulge in the sidewalls) and try to measure the spacing. You may or may not have enough room for a wider tire. One trick is to try to slide a plank between the tires - if a 3/4" thick plank slides thru, you know you have at least that much space to work with. Try other sizes too.

A 235/85 at 80 psi only carries about 300 lbs more per tire. You would have to find one with a higher load range (LR-F or 12 ply rating). I doubt if you will find a G (14 ply) or H (16 ply) in that size tire except in an ST (trailer type) and you can't use those on your coach.

 

[Kirk]

Don't know the axle weight. I was told my RV was max for the 225 75 R16 and to make sure I keep the tires at 80 psi.

You need to at the very least get your RV weighed at a truck scale to know the axle weights and compare them to the weight limits of the chassis. Ideal would be to get the individual wheel weights but that is a little more difficult. For proper tire inflation there are inflation tables published by the tire manufacturers. Here is an example.

 

[Ray-IN]

re: dual tire spacers and wheel spacers, all of them reduce rated axle weight capacity and increase weight load on the wheel bearings.
Yours is the first complaint about multiple blowouts for 16" LR E tires I've ever read or heard about.
Since you do not know the weights for your RV, the only assumption I have arrived at is operator error.
Class C MH's are notorious for having a small CCC.
Please identify the year, make, model of your class C. so see can look up the stats to help diagnose the actual problem.

 

[Gary RV_Wizard]

Yours is the first complaint about multiple blowouts for 16" LR E tires I've ever read or heard about.

Motorhomes with 16" wheels/tires do seem much more susceptible to tire problems. Some of the likely reasons include:

• The max capacity of a 16" tire is often barely enough for the motorhome weight. Even a small motorhome is usually in the medium-duty weight category, but 16" tires fall into the light-duty class.
• Owners of smaller coaches are often newcomers to medium-heavy vehicles and often uneducated in tire inflation concerns, maintenance and risks. It's just a bigger car, right?
• Owners are often unfamiliar with tire aging - it's not a problem with their daily driver.
• 19.5" & 22.5" are simply a lot more rugged construction than any 16".

 

[CharlesinGA]

Yours is the first complaint about multiple blowouts for 16" LR E tires I've ever read or heard about.

THIS thread in April was almost identical

August of '22 blowout

 

[Ray-IN]

I forgot to answer your question. Yes there are higher load range tires available if your wallet is thick enough. Their cost is due to lack of demand. You must know the specs for your chassis to order the correct rims. This tire is the same O.D. as a 16" tire, and in load range H or J.

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[blw2]

Last August I put these tires on my 32ft class C. I've only had one blowout but similar concern....
ordered from tirerack.com
C225/75R-16 KUMHO CRUGEN HT51

the tires I replace were yokohamas I put on after the blowout...they were good tires & looked like they had only about 250 miles or so on them... and they were replaced well before their "time", but I'm being careful.

The new Kumo's have a slightly higher load rating, & I have slightly less worry going down the road with my "stupid design" rig that is basically at capacity or overloaded on the rear axel all the time.... no complaints with them...except I just barely kissed a curb with the outer passenger side on our last outing a few weeks ago, then my son was driving on the same trip and repeated my bonehead move again.... ugh. No visible damage, just a very minor looking scuff, but now I'll worry that the tire has been stressed....

 

[Old_Crow]

I had a set of Kumhos on one of my Jeeps. Those were the longest lasting tires I ever bought. I finally replaced them, not because they were worn out, but because I got tired of looking at them. They ended up on my old F100 for another year after I took them off the Jeep.

 

[TheBar]

I'm guessing if you got tired of looking at the same tires you must be single now

 

[CharlesinGA]

Last August I put these tires on my 32ft class C. I've only had one blowout but similar concern....
ordered from tirerack.com
C225/75R-16 KUMHO CRUGEN HT51

the tires I replace were yokohamas I put on after the blowout...they were good tires & looked like they had only about 250 miles or so on them... and they were replaced well before their "time", but I'm being careful.

The new Kumo's have a slightly higher load rating, & I have slightly less worry going down the road with my "stupid design" rig that is basically at capacity or overloaded on the rear axel all the time.... no complaints with them...except I just barely kissed a curb with the outer passenger side on our last outing a few weeks ago, then my son was driving on the same trip and repeated my bonehead move again.... ugh. No visible damage, just a very minor looking scuff, but now I'll worry that the tire has been stressed....

I think Brad misplaced the C at the beginning of the tire size rather than at the end. This is the same Commercial tire type I referenced above, with the same 3195 lb rating.

KUMHO CRUGEN HT51 225/75R16C

​

 

[blw2]

yes and no....that was a cut and paste directly from my invoice...but yeah, probably the same tire.
Here's a picture of mine when it had zero miles on it...still jacked up at the tire shop....

 

[Old_Crow]

I'm guessing if you got tired of looking at the same tires you must be single now

Is widowed the same thing? Sometimes I don't think so because I'm always thinking of what my wife would have said when I go out and buy something she would have considered "stupid"...like another motorcycle.

Actually, the choice was made to change those tires because I didn't think the tread would last another winter on my commuter Jeep that was driven 168 miles a day, 5 days a week. The pickup was only driven on weekends and then not every weekend, so like I said, I got another year out of them on the truck.

 

[Probe1957]

When you are trying to increase the load carrying capacity of your tires by going with a heavier ply tire, make sure your wheels are rated to carry the increased load.