So a little different than the typical what tire should I get, I'll review those again as I get ready to buy. This question is about tire size.

So I finally got a full size rim (from a SportTrac) I'll use for a spare instead of the dougnut that comes with the FEH. It's currently wrapped in a 255/70/16 tire vs the 235/70 stock. Online calculator says it's 1" taller, reallife it looks more like 2. But I really liked the look of it on the Escape
So the question is, what do different tire sizes mean, other then the obvious more or less rev/mi. I saw one place that talked about size & gear ratio & RPM's, but since we don't have a gear ratio how does that affect our vehicles? It said something like a smaller diamater = faster accel & higher rpm @ cruise, larger diamater = slower accel & lower RPM @ cruise.

So If I decide to get new tires & change size, what is the science behind the #'s? & how will the eCvt react? Obviously the spedo would be off too.

Part 2, spare. So of course now I have the doughnut, I guess it's the same diamater, if I recall when I inspected it a yr or 2 ago it was a 17", but just as tall as the 16's. Would you use that spare or a 255/70/16 as a spare until you could get all 5 to match several months down the road? I don't leave the city, in fact 95% of my driving is less then 10mi from home.
And part 2.5, The original rims & this 'spare' all have that plastic Ford cap in the center, I guess you have to pop those off to store it under the vehicle, since I have the U bolt on the tire lift?

Thanks!
Bryan

Happy New Year!

 

Hi Bryan

I do not recommend changing your tire size and rims for a number of reasons. The rim you purchased may not center the same as the stock FEH rims - stick further out or in than the FEH rims. This will screw-up handling like being out of alignment. Using a spare tire that is 1" or 2" taller will also screw-up handling and the computer. If the wheel sensors are not showing near the same rotation and don't match the eCVT output shaft rotation, you will get a warning light as well as the ABS will not work correctly. Also, the FEH rims are special light weight rims and one heavier rim will cause a big decrease in MPG. Taller tires will generally be heavier also and reduce MPG.

My recommendation is stay with the stock rims and tires Ford Engineers designed the FEH with. An alternative LRR tire the same size and rating is fine, but compare the weight with the stock tires. Heavier tires or rims will always reduce MPG. Even replacing old worn tires with the same new tires will reduce MPG because the old tires have less rubber and are lighter. I just proved this issue with exchanging the worn tires and rims on my '05 FEH with my newer tires and heavier Limited rims on my '09 FEH. This brought my '09 tank MPG average to a record 63.4mpg with 13.6 gallons of E10 going 862.4 miles.

GaryG

 

That's a significant difference that I'd be concerned about. My rig doesn't have TC so I really don't think it'd be a problem as far as the computer is concerned. Mine is an '06 though. As far as weight, meh. Put ONE heavier tire on and I bet the difference in fuel economy would be in the 10ths of a mpg if that.

If it were me I'd get a cheap used tire in the correct size to put on the spare. You can probably get the tire for $10 and get it mounted for next to nothing.

Yes, the center cap would have to come out in order to mount under your truck.

 

You have no experience or knowledge on the subject which is clear in your post.

GaryG

 

Thanks, I understand weight, well just about anything, is going to change mpg.

But how will the eCvt react to different size tires? If a taller tire = lower rpm at cruise on a std gear ratio vehicle, what will it do on ours?

 

As mentioned here Ford does not recommend getting crazy with big tires for safety (i.e. rubbing) reasons. One of the minor headaches with changing rims is maintaining the tire pressure monitoring system, but that's another topic you can read about here. Personally I prefer narrower tires (also known as "pizza cutters" in the off-road world), as I'm currently running 225/75-16s. If you want to go wider, I would say a 245/70-16 tire is only .3" taller and would keep you out of trouble. The newer Escapes have 17" rims optional, and if you might be able to find a set of those take-offs for a reasonable price. When shopping new tires you want to make sure that the load rating is equal or greater to the stock tires' (104), to make sure the tires can handle your Escape's weight.
You are correct that a full size spare fits in the donut spare wheel well (just read your owner's manual for the tire changing procedure), but a 255 section tire will be a tight fit!

 

First of all, you can change the diameter of all your tires but the manual states the PCM has to be reprogrammed for the change. This is so your speed will be calculated to match your speed and the other sensors. The PCM will flag a code if the sensors don't match.

The eCVT provides electric motor Assist to the engine when the engine load gets to 100% after the Warm-Up Strategy. It is very easy to know when you are at 100% engine load by watching the Assist Gauge needle or the SGII. As a hypermiler, I avoid the price you pay with battery drain using Assist. When you are draining the battery in Assist, you are no longer using MG1 to charge the battery. The Atkinson cycle engine has very little torque at low RPM so this causes Assist even at what most people would call slow acceleration.

Now, add more weight with taller heavier tires and you will increase the required torque to get them moving. This will raise the amount of Assist your engine will need to accelerate and maintain speed. Any gain from lower RPM with taller tires just will not happen with the FEH Atkinson engine and eCVT. Higher RPM and more Assist will be needed with heavier taller tires.

The example I used in my last post about changing my tires and rims made me aware of just how much tire weight can effect my mileage in both my FEH's. Even though I use little to no Assist in my '09, I jumped up 5 to 7mpg by trading my new Tours with the worn Tours on my '05 FEH. My wife and Son drive my '05 FEH and I can expect them to only average about 24mpg because they will not even try to hypermile. However, when I drove the '05 after the tire change, I seen a 3-4mpg drop from before the change hypermiling.

GaryG

 

Hi Don

Are you seeing any kind of wear problems with the thinner tires on the FEH rims? The Tours are the same size as the Eco-Plus but are thinner, more of a car tread and weigh 29.4 new. The original Eco-Plus tires were 31 pounds new. Here is what I posted over 2 years ago:

"just got back from Goodyear who mounted the 2 Michelin Latitude Tours on the front of my '05 FEH. I brought a scale to weigh the '05 FEH Rim, so now we can compare the weights. The stock FEH Rim is 2.2 pounds lighter than my new '09 FEHL Rim which is 20.4 pounds. The standard FEH Rim weighs 18.2 pounds. If you add the new Eco Plus at 31 pounds, the total weigh is 49.2 pounds. If you replace the Eco Plus tires with the new Michelins, the standard FEH Rim and Michelin tire would weigh 47.6 pounds each. WoW! This is what my new tires and Rims weigh on the front of my '05 FEH now. The FEHL Rim and Michelin Latitude Tour tires weighed 49.8 pounds, which is .6 pounds more than the stock FEH rim and the Eco Plus. The folks that got the '09 FEH non Limited models have the 47.6 pound tire and Rim set-up."


If you do the math, I dropped 2.2 pounds with the standard FEH rims on my '09 FEH and I can only estimate that the 50% worn Tours dropped me down another ~5 pounds each from the new Tours. This dropped me down from 49.8 pounds with FEHL rims and new Tours to about 42.6 pounds each. That's down 7.2 pounds per tire and a total of 28.8 pounds less to get moving.


The 2011 Explorer Limited I ordered come with the Optional P255/50R20 A/S BSW 20" Hankook tires. If the stock tire and rim will fit where the doughnut is located, I will order a stock rim and tire for a spare and weigh them for comparison later like I did for the '09 and '05 FEH. Hopefully these tires and rims will still be a light weight set-up compared other tires and rims in there class.

GaryG

 

Are you always an arrogant a-hole or is it just here? If you have facts to refute one thing in my post do it.

 

Look J, you basically called me a liar in your first post. Now your calling me arrogant and a-hole because I think you have no experience or knowledge on the subject. The truth hurts sometimes but name calling is not permitted on this site.

I'm not going to call you names as that is a violation of the rules of this site which you choose to violate. When and if you come close to ever break World Records in MPG in the FEH, I'll consider you an expert and knowledgeable on the subject of tires and rim weight. I'm just trying to help people make good decisions from my experiences. Sorry, I thought your post was counter productive to my response.

GaryG