Ford E450 Tire Size

[gmctoyman]

Has anyone here replaced the 16" wheels on their E450 chassis with 19.5" wheels ?

[pianotuna]

Hi,

Sorry, no pictures. Clearance is excellent on the front end.

JeepCollector91 wrote:
How is clearance with the steers?

Thanks.

[JeepCollector91]

pnichols wrote:

How much power loss from large diameter tires you experience climbing up grades of course has to do with how much weight you end up with on the E450 chassis after your build.

As you know the E450 has a 4:56 rear differential ratio, which is a pretty good pulling ratio - compare it to the often lesser ratios in everyday heavy duty pickups. Our 24 foot E450 motorhome is only around 11,800 lbs. loaded, and that rear differential ratio is way over-kill on pulling power up grades. It's great for creeping along off-pavement, though, and when going up grades that ratio helps keep any transmission torque conversion slippage at a minimum as well as keep engine and transmission heat low.

By the way, 215/85R16 tires have a larger diameter than 225/75R16 tires and 215/85R's are what I now run on our E450. Also, in Load Range E they are rated for the same loads as 225/75R's. I also like the 215/85R's better because they're slightly narrower so there's better hot weather cooling air flow between them in the rear dual sets.

I haven't had the opportunity to try out the 6.8L on any grades yet. I know on flat land it has plenty of power but fuel mileage was worse than my 2003 Freightliner Columbia "bobtail" which weighed in at 21,500-lbs empty. Bobtail I would consistently get between 9-11mpg (@ 66mph) with the 12.7L Detroit, 13-speed, and 2.93-gears. When I would carry my Jeep on the back it didn't even know it was there. Was hoping to get slightly better MPG's with the E-450 to haul my Jeep.

[JeepCollector91]

pianotuna wrote:
Hi,

My E-450 is from 2004. I have no problems in the mountains. I am quite close to the maximum weight. I have the 235/85R16 and I did replace the rims to get the correct offset.

I do drive slower than most other RV'ers at just under 80 kph (50 mph).

Thanks for the info. I am going to cut off a lot of weight from the RV so I can haul more. Got any pics of the E-450 with the 235/85R16's? Would love to see it. How is clearance with the steers?

Thanks.

[pnichols]

JeepCollector91 wrote:
I am thinking of going with the 245's all around on the Ford after I remove the Fleetwood Tioga RV body and build something better suited for offroad use. The 235/85R16E are my second choice but that all depends on gearing. Haven't had the opportunity to take the RV fully loaded on any steep grades yet to know if there is any power to spare with the current gears to make up for going with 32's.

How much power loss from large diameter tires you experience climbing up grades of course has to do with how much weight you end up with on the E450 chassis after your build.

As you know the E450 has a 4:56 rear differential ratio, which is a pretty good pulling ratio - compare it to the often lesser ratios in everyday heavy duty pickups. Our 24 foot E450 motorhome is only around 11,800 lbs. loaded, and that rear differential ratio is way over-kill on pulling power up grades. It's great for creeping along off-pavement, though, and when going up grades that ratio helps keep any transmission torque conversion slippage at a minimum as well as keep engine and transmission heat low.

By the way, 215/85R16 tires have a larger diameter than 225/75R16 tires and 215/85R's are what I now run on our E450. Also, in Load Range E they are rated for the same loads as 225/75R's. I also like the 215/85R's better because they're slightly narrower so there's better hot weather cooling air flow between them in the rear dual sets.

[pianotuna]

Hi,

My E-450 is from 2004. I have no problems in the mountains. I am quite close to the maximum weight. I have the 235/85R16 and I did replace the rims to get the correct offset.

I do drive slower than most other RV'ers at just under 80 kph (50 mph).

[JeepCollector91]

I know this is an older thread but I couldn't help myself after reading all replies...

I read that a few here are looking at going with a 2" taller tire? From a 30" to the 235/85R16E 32" tire?
I just bought a 1998 Ford E-SuperDuty (E450?) Tioga Motorhome and it has 245/75R16E (31") on the steers and 225/75R16E (30") on the drives. I swapped things around today to find out if the 245's would have enough clearance between the duals and it had plenty without spacers. Even enough room for snow chains. Aired them down to 30psi and it started getting closer at the bulge but I could still get my hand in there. I had 235/85R16 on my '86 Chevrolet M1008 and they were about 0.5" narrower than the 245/75R16E, and are just over an inch taller. I am thinking of going with the 245's all around on the Ford after I remove the Fleetwood Tioga RV body and build something better suited for offroad use. The 235/85R16E are my second choice but that all depends on gearing. Haven't had the opportunity to take the RV fully loaded on any steep grades yet to know if there is any power to spare with the current gears to make up for going with 32's.

If you end up going with the 19.5" wheels and the G-load range tires one thing to consider is that the compounds may be different and not grip the roads the same on the light weight RV. But they will go a lot further...

[oldtrojan66]

I see from the last post, this thread has not been used in a while. It may not be the place for my question, and I confess, I have not read every single post. My question is about tire profile. When you look at a cross-section of most radial tires, the "corners" are rounded. I bought a tire for a spare and while the same size (235/85R-16), the profile is noticeably different.

The new tire looks more like the profile of a bias ply tire from days gone by. Here's the question, what are the ramifications of using this tire (Sailun) with three Goodyear G614's as, like a spare? Then, would there be any long term problems, leaving them on? It is a less expensive tire and there are just not that many G rated tires out there. The warehouse I called had nine of the Sailuns at $150 less then the Goodyears, but I was told this tire has been discontinued by Sailun, and the ones in the warehouse have a date of 4913, so they are already a year old.

I don't mind this for a spare, but the profile spooked me. Should I be spooked? I don't know if they will take it back since it has been mounted. I know, I was foolish for "assuming" and not viewing the tire before it was mounted.

Thanks in advance for your expert advice.
david

[rondi]

pnichols, Consider the Hankook 7.50R16 tire I mentioned. It is a LR-G, but to get there you need a wheel rated at 100psi.
http://www.hankooktireusa.com/Product/product.aspx?pageNum=1&subNum=1&ChildNum=4&FnCode=04
Most wheels for 16" tires are only rated for 80psi--per my Ford dealers parts dept. That's why I asked about your SW Wheel wheels you bought. Is there anything stamped on them that would indicate the max psi? There is nothing on the link you posted. and your correct about the higher load range tires not increasing the axle weight rating and the axle bearing are now the weak link. Altho chances are great that no catastrophic failure will occur like blown tires.

John, Your correct about the Alum wheels---IF I could find them for the E450 and 17.5" (or even 16") wheels with a (4.88" bore) hub mounted wheel and an 8 x 6.5" lug bolt pattern with LR-F or G rating. IF i bought regular painted wheels, I fear they be chipped & rusted in a few years here in N ID, and I'd pay $300 for the wheel liners. With Alum the cost now comes down by $300 :). I had Alcoa Alum wheels on our Class A and they never looked nice--they needed a power polish every month--too much work for me! The coated ones would be what I'd want--If anyone knows of these--PLEASE post a link.

Ron

[pnichols]

rondi wrote:
In my case the weight on my rear axle is over the 9600lb limit with virtually nothing added in the rig--it came overweight from the factory!

Of course going to heavier duty rims/tires will do nothing to alleviate the rear axle overloading - right?

I'm with you on the LR G tires, but I'd like them for another reason. We go (mildly) offroad with our E450 Class C, so I'd like LR G tires on our rig for the better rock puncture resistance that they provide. I wish I could find some quality LR G tires but still in 16 inch rim size ... I'd still only inflate LR G to 80 lbs, but benefit from their thicker material construction.

[John___Angela]

Hi folks. This has been an interesting thread to follow. We have a E350 based motorhome and had all of the problems listed in the thread. Heavy rear end, light front end and of course the clearance issue. We solved the problems with a combination of some of the techniques you mentioned including tire profile, supersprings, shocks, heavy sway bar, moving the spare to the front of the motorhome etc etc. Thats all history and the motorhome now drives like a sports SUV. But what I wanted to mention is if you are considering new rims, consider going to the Aluminum rims. No more hub caps, easy tire fills, nice to look at and easy to clean. Yes it will add a thousand bucks to the project but its something to consider.

Hoping it all works out y'all. Happy and safe trails.

[pianotuna]

Hi,

They came from 235/85R16 and I'm running Toyo tires on them on the advice of my tire seller.

rondi wrote:
pianotuna--where did you get your new wheels? Do you know what the max air pressure is for them? Ron

[rondi]

pnichols--one of the main reasons is to increase the Load Rating from E, which is a 10 ply tire to an F or a G. You can't do that with the stock wheels--which are matched to the tire limit of 80psi--per my local ford dealer's parts dept.

In my case the weight on my rear axle is over the 9600lb limit with virtually nothing added in the rig--it came overweight from the factory! I guess there is no law or regulation that forbids that--but common sense should. I had 2 leaves each side added to the stock 11 leaf spring pack to raise the rear a couple of inches--and they did that. Ford is the one to blame here. The E450 they spec at 14,500lbs and provide LR-E wheels & tires, whereas an F350 (rear axle copied from the online spec=9650 lbs. (F-350 DRW)) and has 17," 18" or 20" (F-250/F-350) truck tires and this isn't even an F450. Ford knows their rig will be overloaded and probably tell the dealers--just watch all the class c rigs come in for the chassis work that you'll get 🙂
The rigs made today are almost identical to the ones made in the first part of this century.

And remember--very, very few rv owners even know about these forums, and are driving around unaware they are overloaded. We know some.
Ron

[rondi]

pianotuna--where did you get your new wheels? Do you know what the max air pressure is for them?

In my prior post I mentioned i considered the Hankook 7.50R16LT tire which is a Load Range G tire, but has the same load rating at 80psi as my stock tires. since the wheels are probably rated at only 80psi (this from my local Ford parts dept) i canceled that order and now I'm considering the 17.5 commercial duty real truck tires.

Ron

[pianotuna]

Hi,

In my case staying with 16 inch still meant new wheels. Of course more load carrying capacity for the tire does nothing for the axle ratings.

Going to a 17.5 inch possibly is better because the dual spacing remains the same so there is less stress on the axle. But tire cost also goes through the roof compared to 235/85r16.

I would not want to have anything taller nor wider than what I have now. There is not a lot of "spare space" in the rear wheel wells.

I roll a lot of distance and will wear out the tires before they "age out".