Tires, Wheels, & Financials - (Pagosa Springs, CO)

I wanted to get on the phone early this morning and figure out our tire situation.  Linda & I agreed that there would never be a good time financially to upgrade our tires and wheels.

And we've had so many friends with large trailers (and some not so large) that have had blowouts with the same tires we have - the Goodyear G614 LT235/85R16 Load Range G tires.  In fact, Mark & Dale Bruss who I linked to yesterday, had a blowout at the end of August with the same tires.

Like us, they were going to wait to upgrade until next year.  Well, that changed quickly.  So, the safety factor and peace of mind are just too important to put the decision off any longer.

A quick tire refresher.  As Mark says, "Your tires are the foundation of your RV.  Everything is supported on your tires.  The selection, monitoring, and care of your tires is crucial to the safety of your RV experience."

Reading A Tire

Let's look at the Goodyear G614s we have - LT235/85R16 Load Range G.

LT = Light Truck (For most car tires the numbers are preceded by a "P" for passenger)

235 = The width of the tire in millimeters (To convert to inches divide by 25.4);  235 mm / 25.4 = 9.25 inches)

85 = The aspect ratio; This is the ratio of sidewall height to width; So this tire's sidewall height is 85% of 235 mm or 199.75 mm; Converted to inches that would be 199.75 mm / 25.4 = 7.86 inches (9.25 inches X 85% = 7.86 inches); Keep in mind that is one sidewall from the ground to the tire wheel/rim - so there is another 7.86 inches from the top of the wheel to the top of the tire;  High performance tires, which we don't need for RVs, have low aspect ratios because the shorter the sidewall, the better the tire performs in turns at higher speeds

R = Radial (a B would indicate bias tire construction, but we're dealing with radials on full-timing RVs)

16 = Wheel diameter in inches;  So this tire requires a wheel/rim of 16 inches

Load Range G = maximum load of 3,750 pounds at the maximum pressure of 110 psi for this tire; Although the tires have load range codes, they also indicate the exact maximum loads and pressures on the sidewall

Note:  Load ranges are indicated by letters on Truck tires (the higher the letter, the higher the load capacity).  See Truck Tire Load Range Chart  Load ranges for Passenger tires are indicated by numbers with higher numbers having higher capacities.

Changing Tires   

The reason we want to change tires is because we don't have enough cushion on the weight capacities of our current tires.  In a perfect world with unlimited cash, we would change our 7,000 pound axles to 8,000 pound axles and change the tires and wheels and everything else necessary for that change.

However, we have been told by the professional RV weighers (we have weighed twice) that we are probably okay on the axles, but really should change the tires since we are overweight on individual tire positions.  That is more of an issue with the design of our fifth wheel than anything.  We have three slides on our left side with most of our weight concentrated there.  We are talking "built-in" weight, not weight we can shift.

So what are the considerations in changing tires?  All experts say you should have the same size tires with the same capacities.  So, it's not just as easy as getting better tires for our left side.  Also, there are no tires we can find that have higher capacities and fit on 16-inch wheels.  The wheels have to have the same or higher capacities as the tires.  High capacity tires on lower capacity wheels doesn't help.  :)

Therefore, to upgrade and get the weight capacity we want, we had to research changing tires and wheels.  So what did we have to consider for that?  I went through tire websites, and RV websites and forums.

If the new tire diameters are too high, we might have clearance issues between the trailer and between the tires themselves.  If the tires are too wide, then we might have fender clearance issues.  If the wheels don't fit on our current hubs, we would have to change hubs, brakes, and other components.

So the goal was to find tires with a higher capacity and similar size that fit on wheels that were compatible with the current hubs.  Everything I could find pointed to 17.5 inch wheels with H-rated tires with a load capacity of 4,805 pounds per tire.

I narrowed down the choices, but was still confused enough to need help before pulling the trigger.  It's too expensive a decision to make a mistake and buy incompatible tires/wheels.

Fortunately, that's when I discovered Mark & Dale had just gone through the process and had the exact same tires and axles we have.  After reading his New Sized Tires page, I knew he had done the research and come to the same conclusions I had.  Still, I needed reassurance so I called him this morning.

I got the reassurance I needed.  We're also going with the 17.5" X 6.75" 865 Aluminum Hi-Spec Series 3 Trailer Wheel with 4,850 pound capacity from Trailer Tire & Wheel Supermarket.  In addition to Mark and the folks from Weigh-It Portable RV Scales, I've gotten other suggestions to use this company.  These wheels will fit on our hubs and axles without modification.

And for the same reasons as Mark, we are going with the Goodyear Unisteel G114 LHT 215/75R17.5 H-Rated tires.  These tires are actually a little narrower (215 vs 235 mm, about 8.5 inches vs 9.25 inches) and .2 inches smaller in diameter so there are no clearance issues to worry about.  Because of the narrower width and lower aspect ratio, the sidewalls are shorter and offset the 1 1/2 inch larger wheel.  So it's a smaller tire with greater strength and better performance in turns.  However, the "contact patch" (the amount of tire touching the pavement based on width) is about 3/4 of an inch less.

Note:  There is a G114 LHT 235/75R17.5.  So why didn't we go with that wider tire that actually has even more capacity?  Well, a couple of reasons.  First, it is well over an inch more in diameter than what we currently have so there are compatibility issues.  Second, it has a speed rating of 62 mph whereas the smaller tire has a speed rating of 75 mph.  Like Mark, we don't intend to go 75 mph, but we like the extra cushion.  In fact, almost all the other tires requiring 17.5 inch wheels have the lower speed rating.  Lots of folks like the Michelins in Mark's tire comparison table except for the speed rating.  Oh, the G114s also come in an F Load Range in the 215/75R17.5 size - gotta be careful to not order that lower capacity tire as that's what we were quoted by one dealer.  :) 

I called various Goodyear stores on our path to Arizona to get pricing on the tires.  They either couldn't find the tires or they priced them between $370 and $390 each.  One store came down to $349.  And that didn't include sales tax or labor and was going to end up around $430 per tire.

I called Trailer Tire & Wheel Supermarket since their website says they can package the tires with the wheels.  I just assumed their price and the shipping would be too much.  I was wrong.  :)

Their price was $287 per tire.  And they will mount the tires on the wheels for free and balance them for $6.  The written quote for four tires/wheels was for $2,230 including shipping to Buckskin Auto up the road.  All I'll have to do is have them mounted.

We're hoping to place the order and get them on the truck Monday.  :)

The Rest of Our Day

Whew!  With that decision finally made, we had to pick up some toner for our printer and run a couple other errands.  The main goal was to fill the truck up with diesel.

With our ten cents off using our City Market card, we filled both tanks on the truck for $130 at $3.29 per gallon.  The last time we filled up at the end of June it was $4.89 per gallon.  Wow!

On the way back, we stopped at Buckskin.  I wanted to make sure they would accept the tires/wheels if I shipped them there.  It was fine.

I also made an appointment for next week to get the truck serviced and the tires on the truck rotated.  The tires are showing some wear and they haven't yet been rotated.  We had budgeted for a service in October, but I guess early November will do.  :)

Speaking of budgets, I spent the rest of the afternoon and early evening doing the October Financials.  The entry is below this one.  Another thing off my list.  :)

Linda is on a beading frenzy as she has a few orders to fill.  And she made her Taco Soup recipe in the crockpot for dinner.  Always good on a chilly night.  :)

And that was about it for our day.  We may or may not be more exciting tomorrow.  :)

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Comments

[bob schmader]

Howard, I know exactly what you want to obtain with your tire exchange and I can understand it but they will be still be rated at 3500# each with the 7K axles. It will definetly be more safe and will give you more peace of mind. Have you confirmed that the wheels will definetly fit on your hubs for 16" wheels ? Will the new wheels also fit on 8K axles if you decide later that is the way to go.
I went through all this before when I had the McKenzie Medallion. With the Elite Suite I am still borderline. The more you can haul the more stuff you load in. It's a never ending battle.
Good Luck on everything.
Bob

[bob schmader]

Howard, I forgot to ask you in the other post. Are you also ordering your spare tire and wheel ?
Bob

[Darby Corwin]

Howard I went through the same thing with tires on a Winebago Motor Home I used to own. It had 16 inch tires and I was forever having blowouts because they would not carry enough weight. I looked and looked and I finally put 6 Goodyear tires on that was H rated. The only thing is these tires were made for trailers. I was warned about putting them on but I never had a bit of problems with them and it solved my blowout problems. I never had an ounce of trouble with them. I know it is scary when you never know which one will blow next. Out of 6 Michelins I lost 5 in a period of about three months. The bad thing each time one would blow on the rear it would tear up the motor home to the tune of about $1500.00 each time. Good luck in your decision.

[Mike Ward]

Howard,

Believe it or not, in Metro Detroit you can find gas as cheap as $2.19 per gallon. That's not a misprint, $2.19 (not $3.19). Don't know why it plummeted so far in our area, but I'm not complaining.

[Bob Ebenreck]

I'm sure you already know about this but I thought I would throw out this reminder. When your new tires come in, don't forget to check the date they were manufactured. You don't want to be buying tires that are already three years old or more.

[Teresa]

So my engineer husband asked why you aren't considering steel wheels in place of aluminum? He says they are stronger (pound for pound) and cost less. Just curious.

[Howard]

Teresa, I may not have a really good answer for you, but here goes.

First, our rig came with steel wheels from the factory and those wheels were recalled due to cracking and replaced with aluminum.

Second, aluminum is lighter.

Third, the 17.5 inch steel wheels I've found don't have the load ranges of the 17.5 aluminum. We'd be right back in the same place.

Fourth, steel may be a stronger metal, but from what I've read it is certainly not clear that steel wheels are stronger based on the different construction methods.

[Teresa]

Those sound like good reasons. We went through deciding about axles when we ordered our New Horizons this year. We opted for three axles to be safe. It's six of one, half dozen of the other, as the third axle cost more (of course) and we now have six wheels and tires to monitor.

Oh, the husband also mentioned to remind you to check your bearings (don't ask me why, it's not my job to do the mechanical stuff on our RV, I just drive it).

And one more thing, make sure your warranty on your axles, etc. won't be voided because of the change in the wheels and tires. Just a thought. You got us to thinking and we pulled out our folder on our 5th wheel to read what size axles, etc. we had. With the 3 axles at 7,000 lbs. each, we are in good shape. But the husband (I tease him and call him that so he won't call me "the wife":) said that doesn't mean I can load the trailer up to the max - he's just no fun :)

We were in Kentucky last week, beautiful state. We thought of you as we passed Louisville on our way to Bowling Green to see the Corvette assembly plant and museum.

This really is a beautiful country and like some people say, we are not red states and blue states, we are the UNITED STATES and aren't we so lucky to live in a country where we can have differences of opinions and the freedom to express them.

GO VOTE !

[The Bear II]

Howard,

It amazes me that the trailer manufacturers use the lowest weight axles possible instead of heavier weight axles to insure our safety. Our 5th wheel has 6000 lb axles which means the brake shoes aren't much bigger than those found on older passenger cars. Like you I would much rather have 8000lb axles. If I was ordering the 5th wheel today, I'd go with the highest rated axles and a disc brake system for peace of mind.