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Tires E-350/450: Stock 225/75? Tall 215/85? Wide 235/85?

BigToe
Explorer
Explorer
Tire Choices for Ford E-Series Cutaway Class C Motorhomes


What replacement tires did you put on your Class C motorhome built on a Ford E-350 or E-450 (aka E-Superduty in older rigs) cutaway chassis, and what were your reasons for your tire selection?

Did you stick with the stock tire size of LT225/75r16 ?

Did you go taller and skinnier, changing to LT215/85r16 ?

Did you go taller and wider, changing to LT235/85r16?

Did you upgrade to 10 ply rating Load Range "E"? (If you have an older E-350 originally specified with 8 ply rated Load Range "D")

Did you switch to European style 225/75r16C, such as what is specified for Euro van cutaways like the Transit and Sprinter?

Have you had an experience with any particular brand and model of tire for your E-350/450 RV that caused you to swear "never again"?

Do you have a particular brand and model of tire that is your trusted "go to"?


Thank you!
42 REPLIES 42

BigToe
Explorer
Explorer
Thank you Pianotuna!

pianotuna
Nomad II
Nomad II
BigToe wrote:
Tire Choices for Ford E-Series Cutaway Class C Motorhomes



Hi BigToe,

My oem tires were overloaded on the driver's rear side. Axle rating was not.

I chose to replace the wheels and moved to LT215/85R16 from Toyo. This corrected the overload situation.

This gave me a little more clearance.

It is extremely important to have the correct wheel size to width. A spacer is possible but....not as reliable (read possible not quite as safe).

Wider tires would not have fit on the rear duals.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

BigToe
Explorer
Explorer
Grit dog wrote:
@bigtow
What part of what you quoted makes using a directional tire unsafe or undesirable to use as a spare tire?
The difference between the right or wrong direction is literally not getting “optimal” traction. Sort of like a brand new tire vs one that is 50% worn out. Hardly worth the consternation about using one as a spare tire.


Neither Michelin nor I said anything about reversing a directional tire being "unsafe."

Michelin said that reversing a directional tire within the first 50% of tread life can result in undesirable tire performance, as well as undesirable accelerated treadwear, as detailed in the url linked Product Bulletin posted earlier, where the relevant text was also quoted within the post.

On Edit, to address the "consternation" about the spare:

For my requirements, there is no difference between the spare tire and any other tire on the rig. All tires, including the spare, are qualified to be run full time. When there is a need to use the spare tire, there is no need to remove the spare tire later to put back the removed rim with a repaired tire. The spare tire becomes the service tire, while the repaired or replaced tire becomes the spare tire.

Hence, a spare tire that can be mounted in any position on either side of the vehicle is more desirable to me than a directional tire, which is limited to only half of the available mounting positions.

I rotate the spare tire with the steer tires, to keep the wear down of the spare tire the same diameter as the wear down of all other tires. Thus the spare is indistinguishable from a service tire throughout the life cycle of that set of tires. A directional tire would disrupt that preventative maintenance.

Grit_dog
Nomad III
Nomad III
pnichols wrote:
What I would REALLY PREFER on my 11,800 lb. (~fully loaded) 24 ft. Class C are Mud/Snow tires that are so over-spec'd for my MH such that if I blow a rear tire in the dually set - I can drive aways without changing it in situations where it blows and it is inconvenient or unsafe to stop and change it!!

i.e. I had an outside dually Michelin M/S LT LRE blow once years ago on a hard surface 4-lane road with light traffic. I was only a few miles from a small town, so I slowed down to ~10 MPH and drove all the way into the town and had a gas station attendant change it. Of course the other Michelin tire within the dually set was drastically overloaded while I traveled on it. That tire went on as if it had never been overloaded and provided several more years of service.

In other words - another parameter to shoot for in choosing tires for the rear of a rear-dually Class C is ... "can 3 tires in the rear (when one is flat) safely carry you along for aways at low speed until it can be changed?" This is what I call having a "redundancy" tire arrangement in the rear of a dually chassis - and it takes very rugged tires back there that have a generous-as-possible weight carrying margin over what they normally carry day-in and day-out.

P.S. I keep 80 lbs. of pressure in the rear tires all the time. I've compensated for the previously stiff ride in the rear by installing variable rate shocks in the rear that function as "no shocks" on highway cracks and as "heavy duty" shocks on roadway curves and in side-winds.


So basically your old tire did exactly what you “wish” for.
You could always go with 19.5s. But at almost 6klbs load per side it’ll still be overloaded a bunch.
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold

Grit_dog
Nomad III
Nomad III
@bigtow
What part of what you quoted makes using a directional tire unsafe or undesirable to use as a spare tire?
The difference between the right or wrong direction is literally not getting “optimal” traction. Sort of like a brand new tire vs one that is 50% worn out. Hardly worth the consternation about using one as a spare tire.
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold

Grit_dog
Nomad III
Nomad III
All I can say is there are more options than the E load version of 225-75-16s.
And I don’t recall the OP (who the thread is about) even surmising much less knowing what his axle weights are.
If you need the tire capacity, you need the tire capacity.
And if you found them for basically the same price that is great as well.

And to be fair, the guess I have a bit of a different perspective than most weekend warriors whose experience with heavily loaded vehicles is a camper, some extra home improvement materials from Home Depot or a load of Moo Doo for the flower beds.
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold

pnichols
Explorer II
Explorer II
What I would REALLY PREFER on my 11,800 lb. (~fully loaded) 24 ft. Class C are Mud/Snow tires that are so over-spec'd for my MH such that if I blow a rear tire in the dually set - I can drive aways without changing it in situations where it blows and it is inconvenient or unsafe to stop and change it!!

i.e. I had an outside dually Michelin M/S LT LRE blow once years ago on a hard surface 4-lane road with light traffic. I was only a few miles from a small town, so I slowed down to ~10 MPH and drove all the way into the town and had a gas station attendant change it. Of course the other Michelin tire within the dually set was drastically overloaded while I traveled on it. That tire went on as if it had never been overloaded and provided several more years of service.

In other words - another parameter to shoot for in choosing tires for the rear of a rear-dually Class C is ... "can 3 tires in the rear (when one is flat) safely carry you along for aways at low speed until it can be changed?" This is what I call having a "redundancy" tire arrangement in the rear of a dually chassis - and it takes very rugged tires back there that have a generous-as-possible weight carrying margin over what they normally carry day-in and day-out.

P.S. I keep 80 lbs. of pressure in the rear tires all the time. I've compensated for the resulting stiff ride in the rear by installing variable rate shocks in the rear that function as "no shocks" on highway cracks and as "heavy duty" shocks on roadway curves and in side-winds.
2005 E450 Itasca 24V Class C

SJ-Chris
Explorer
Explorer
Grit dog wrote:
SJ-Chris wrote:

LT225/75R16C 121/120R: The reason I use them is because they have 2000lbs of extra carrying capacity at 80psi. Gives me peace of mind. I believe they are safer. Safety is important to me.


Personally, I see no downside in having extra weight carrying capacity. In my opinion, they are less likely to blow. If one does go flat, the remaining one that is temporarily carrying the full load will be less likely to also blow.

Note: You should never intentionally overload your rear axle.

Safe travels!
Chris


No downside other than availability and price. Sure, if one needs the added capacity, great. But based on your last statement, that's not likely unless one is actually overloading the "real" axle capacities (aka the 10-11klb range) of the vehicle.
And if the extra capacity is needed, barring some obscure tire clearance issue on the RV, there are other options that are of similar or same capacity and not an obscure Euro tire size (albeit not as obscure as years past with the amount of Sprinter type vans running around.

Overkill is fine, it's one person's own money vs peace of mind I suppose. Just pointing out the (not obvious to everyone) differences and costs/challenges for little to no real world gain.


I hardly consider it overkill...

I went through ZERO hoops/effort to buy tires that each have an extra 500lb carrying capacity. They aren't Euro tire size. I believe they are from South Korea or Japan. They have similar Commercial load rated tires (121/120 load rating) at Big-O tires, Firestone, America's Tires, Discount Tires, CostCo, etc. AKA just about everywhere. I think the ones I got were $15 more per tire when I bought them compared to a corresponding E-rated load tire.

Here's why it isn't Overkill...
225/75R16C rated duallies in the rear have a 80psi carrying capacity of 4 x 2975 = 11,900lbs

whereas 225/75R16E E-rated duallies in the rear have a 80psi carrying capacity of 4 x 2470 = 9,880lbs

Let's assume your rear axle was at a maximum weight of 9,600lbs. Would you rather have the E-rated tires that have only a 280lb margin, or the C-rated tires that have a 2,300lb margin? I would rather have the C-rated tires. 280lbs is 2.8% of buffer/margin. 2300lbs is 23% of buffer/margin. 10x more buffer/margin. I consider that a significant gain and worthwile (at least for me).

Personally, I don't feel comfortable with potentially only 2.8% of buffer/margin.

Next question: Does the typical RVer check your tire pressure EVERY DAY before they drive? I'm guessing 99% of people do not. (I have a TPMS so I can see always). What happens to these margins when the tires are actually at 75psi instead of 80psi? Or 70psi? Or 65psi? Answer: It spells trouble for E-rated tires, but the Commercial load rated tires still have plenty of carrying capacity buffer.

Side note: Nobody should ever overload their rear axle, even with tires that can handle a heavier load. What % of RV owners know (weighed at a scale) how much their rear axle weight is? Probably less than 5%.

All good. Just my opinion. I'll pay a tiny bit more for what I perceive to be a large extra margin for the potential safety of family and friends. Have yet to have a blowout on my two 30' Class C RVs that have these Commercial load rated tires on them. Everyone is free to choose whatever tires they want for their RV.

Safe Travels!
Chris
San Jose, CA
Own two 2015 Thor Majestic 28a Class C RVs

Grit_dog
Nomad III
Nomad III
SJ-Chris wrote:

LT225/75R16C 121/120R: The reason I use them is because they have 2000lbs of extra carrying capacity at 80psi. Gives me peace of mind. I believe they are safer. Safety is important to me.


Personally, I see no downside in having extra weight carrying capacity. In my opinion, they are less likely to blow. If one does go flat, the remaining one that is temporarily carrying the full load will be less likely to also blow.

Note: You should never intentionally overload your rear axle.

Safe travels!
Chris


No downside other than availability and price. Sure, if one needs the added capacity, great. But based on your last statement, that's not likely unless one is actually overloading the "real" axle capacities (aka the 10-11klb range) of the vehicle.
And if the extra capacity is needed, barring some obscure tire clearance issue on the RV, there are other options that are of similar or same capacity and not an obscure Euro tire size (albeit not as obscure as years past with the amount of Sprinter type vans running around.

Overkill is fine, it's one person's own money vs peace of mind I suppose. Just pointing out the (not obvious to everyone) differences and costs/challenges for little to no real world gain.
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold

BigToe
Explorer
Explorer
Grit dog wrote:
And to dispell another myth posted by BigToe, there is no harm in using directional tires backwards other than less than “optimal” traction that is provided by the design of the tread.


Here is the Product Bulletin Issued by Michelin on April 29, 2019:

The C-metric sizes of the MICHELIN Agilis® CrossClimate® tire line utilize a directional tread pattern. These tires have arrows molded into the sidewall of the tire to indicate the intended direction of rotation. To maximize tire performance, it is important that directional tires be mounted correctly on wheels to ensure that the directionality is respected when mounted on the vehicle.

Pairs of steer tires and pairs of drive tires should be mounted such that one tire has the arrows pointing clockwise, and one tire has the arrows pointing counter-clockwise. For vehicles equipped with dual rear wheels, two rear tires should have the arrows pointing clockwise and two rear tires should have the arrows
pointing counter-clockwise.

To optimize wear performance, it is recommended to operate directional tires exclusively in their indicated direction, at least during the first 50% of treadlife. However, once directional tires are worn to greater than 50% of their initial tread depth, there is no negative effect of running them in a direction opposite to the indicated direction of rotation.


_________________________________


Not a myth. Simply the straightforward (haha) directions (haha) from the tire manufacturer.

1. Optimizing wear performance sounds like a good idea, because tires to be too expensive to waste by not following the instructions, thus increasing the likelihood of the tires wearing out prematurely.

2. Optimizing tire performance sounds like a good idea, because lives are too important to put at risk by not taking advantage of all the tire wet traction engineering one paid for with the price of the tire from installing them the wrong way.

3. In my RV usage case, the tires will never reach 50% tread wear before the tires age out. Therefore, if I were to buy directional tires, I would be stuck using them directionally for their entire service life, as they will never wear down to the point where directionality no longer matters.

4. The tire manufacturer knows more about the tires that they engineered and built than I do, so I'll follow their instructions.


Edited to add URL Link to Michelin's Agilis Cross Climate C-Metric Product Bulletin:

Agilis C-Metric Rotation Bulletin pdf

SJ-Chris
Explorer
Explorer
I appreciate the kind words BigToe!

We are all here to learn. Because of the expert information from many many people on this and other RV forums, I have learned quite a bit and have been able to do many projects/fixes on my RVs that I otherwise would not have been able to do. Saves a lot of $$$ not having to go to the local RV shop. And helps me be safer. I enjoy sharing what I have learned so that others can benefit and avoid problems/issues.

One last thing about tires... It may be putting too much faith in a government entity, but I also naively think that the Department of Transportation (DOT) must test/verify all tires that they are putting their stamp on prior to them going on the market/road. Or at least have some sort of monitoring system in place for reports/complaints. The DOT must have as part of it's general mission something to the effect of "We don't want tires on fast moving heavy vehicles falling off all over the place causing tons of accidents and deaths". This makes me (again, possibly naively) a little less worried about brands.

Safe travels!
Chris
San Jose, CA
Own two 2015 Thor Majestic 28a Class C RVs

BigToe
Explorer
Explorer
And your recommendation was greatly appreciated, Chris!

I was unfamiliar with Nexen tire's offerings in this size until you identified it.

The CT8 HL that you use is the OEM tire that Stellantis fits to the Ram Pro Master, in the 121/120R load index that you are highlighting. When a tire is produced as original equipment for an OEM vehicle manufacturer, it stands to reason that the CT8 HL has been put through an extra layer of engineering and vetting by the vehicle manufacturer, for the sake of their own liability. That says that while Nexen may not be as well known of a brand as Michelin or Goodyear, that particular CT8 HL Nexen tire has been approved by VW and Stellantis for their new vehicle brands to ride on it.

I'm not a tire expert either, so the questions that PNichols asked above are questions that I was curious about as well. Where a given brand of tire produced in two iterations for the same application and usage has the same material weight, why would one tire have a higher weight capacity than the other? What makes the higher rated tire stronger, even while having less material weight?

Michelin claims to use over 200 different raw materials to produce a tire. while another tire manufacturer claims to use only 17 different materials. While it can be assumed that Michelin, being the oldest tire company, and having introduced significant innovations to the industry such as radial tires, is more advanced... some of the ingredients introduced into tires today are to make them more environmentally friendly at end of life, and that sophisticated soup of materials may not necessarily translate into tire longevity.

RV tire purchases are not routine for the long term RV owner who does not regularly trade in their RV, but rather are a once every 7 to 10 year expense now exceeding $2,000.00 to replace tires that have plenty of tread left but simply aged out. Blow outs are a much bigger deal on an RV than in a car, for reasons which SJ-Chris already mentioned. These factors inspire more questions on the selection of RV tires versus daily driver tires that may see more frequent replacement.

Earlier, I failed to mention that Firestone, the manufacture of the Steeltex R4S that used to be Ford's OEM tire on the cutaways 20 years ago, now offers the Transforce CV tire in the 121/120R load rating.

Unlike the F-53 Class A motorhome chassis, or any given modern day 1 ton and higher pickup or chassis cab, the Ford E-Series cutaway chassis challenges the limits of the Ford recommended LT225/75R16E tire size. I began this thread asking if any Class C owners have changed tire sizes, whether it be for increased tire capacity margin, increased ride height/ground clearance, increased approach/departure angle, increased tire contact patch, or decreased contact patch to penetrate through light snow to the ground.

The relatively recent emergence of the C-Metric tire being offered in the US, with higher load index ratings, have broadened the weight capacity margin... but a tire still has to do other things besides carry weight.

Wet traction comes to mind. Not skidding out in the rain. Not spinning wheels and burrowing in on grassy slimy surfaces at unimproved campground. That sort of thing. A tire must still be a tire in all other respects besides carrying weight.

It appears that the ETRTO standard calls for Curb Guards (anti abrasion buttresses on tire side walls where they might repeatedly grind against a sidewalk curb in urban parcel delivery applications) in all C-Metric tires, and this is another benefit that is useful when navigating Class C RV's through destination cities.

Asking about what tires people use and reciprocating the favor by posting what tire explorations I have made, is part of the process of learning, and I appreciated the opportunities to learn from you.

SJ-Chris
Explorer
Explorer
Grit dog wrote:

And why would one intentionally use tires (225-75-16C) that are far less popular and less available than all the applicable comparable tires that are commonplace and can be found at any tire shop virtually anywhere in North America?


LT225/75R16C 121/120R: The reason I use them is because they have 2000lbs of extra carrying capacity at 80psi. Gives me peace of mind. I believe they are safer. Safety is important to me.

I carry a spare LT225/75R16C 121/120R. I've yet to have a flat with these, but if I do I have a replacement in my spare. If for some strange reason I got 2-3 flat tires at the same time, well I'll deal with it if it happens. If I got two flat tires and was somewhere that only had the E-load rated tires for sale, I would have them put those on the front axle and move the Commercial rated tires to the rear.

Personally, I see no downside in having extra weight carrying capacity. In my opinion, they are less likely to blow. If one does go flat, the remaining one that is temporarily carrying the full load will be less likely to also blow.

Note: You should never intentionally overload your rear axle.

Safe travels!
Chris
San Jose, CA
Own two 2015 Thor Majestic 28a Class C RVs

Grit_dog
Nomad III
Nomad III
And to dispell another myth posted by BigToe, there is no harm in using directional tires backwards other than less than “optimal” traction that is provided by the design of the tread.
There are about 5 other reasons to maybe carry 2 spare tires. This is absolutely not one of them….
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold