changing wheels and tires

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TexaCali

Well-known member
Joined
May 12, 2014
Messages
122
Location
San Jose, CA
I'd like to give my FFE a bit more aggressive look and so I'm considering replacing the wheels with black 18" (which would require 225/40-18 tires). This raises several questions:

1. Does spoke design have a significant impact on wind resistance (and thus range)?

2. A 225/40-18 will lower the car slightly from the 225/50-17. Is this likely to reduce drag (and increase range)? Will the effect be noticeable?

3. How does one re-calibrate the spedo for the slightly smaller wheel?

4. Unfortunately the Michelin stock tires aren't available in this size. Any recommendations for a LLR tire in this size? Obviously I don't want to give up any range to rolling resistance if I can avoid it.

Thanks!
 
Why don't you use the size tires Ford uses as the summer tire (performance really) option for the ICE Focus?
235/40-18
They used this tire as optional equipment from Ford:
Michelin Pilot Sport 3

There is no offset or diameter change with that wheel tire combination.

Your questions - don't know the answers to a certainty just my opinion:

1) Spoke design must have some kind of affect - look at the ugly mostly flat wheels they put on the Prius. Those designs happened after wind tunnel tests and there must be some affect. The wheels for the FFE aren't unique - they are the same ones used on the C-Max (if I remember that correctly). You would probably never notice the range difference - but it is cumulative, a bunch of small things add up to one big thing.

2) Maybe lower will reduce drag. It will also allow you to hit more curbs and speed bumps. Like above, you probably won't notice the difference, it is a small cumulative thing.
The Tesla used to run at a lower height at highway speeds. After the two cars caught debris, piercing the battery, and the cars catching on fire; Tesla changed the program to lower the car at 100 MPH (you can adjust that value). At 100 MPH when the car lowered I didn't see the consumption go from 430 Wh/mile to 400 (not far off from what it uses at 100 MPH). There was no noticeable difference.

3) you don't recalibrate the speedometer - there is no setting to do that.

By the way - Michelin Primacy MXM4 are available in 235/40-18. That's the tire Tesla uses as standard equipment for 19 inch wheels.
 
I've noticed the speedometers in my recent cars have been extremely accurate. I've wondered whether they constantly self-calibrate against the GPS.
 
EVA said:
Why don't you use the size tires Ford uses as the summer tire (performance really) option for the ICE Focus?
235/40-18
<snip>
By the way - Michelin Primacy MXM4 are available in 235/40-18. That's the tire Tesla uses as standard equipment for 19 inch wheels.

Thanks! That solves a lot of problems and keeps the circumference much closer to stock. Hopefully the Primacy's grip a little better without increasing rolling resistance. The OEM (Energy Saver) tires seem to break free at the slightest hint of accelerator travel. I'm scared to think what they would do in a panic stop or evasive swerve. My traction control light comes on just turning out of driveways and accelerating into traffic.

BTW - in doing some research it appears going wider (for the same load) may actually reduce rolling resistance, and the reduction in rolling resistance may be greater than the increased wind resistance.

Now to find some light weight wheels I like and don't cost an arm and a leg.
 
EVA said:
TireRack is my best friend.

Yep, been spending way too much time looking at wheel and tire options on tire rack :lol: . I've also been researching 17" vs 18" wheels (esp in the ICE Focus owners forms) and I may just stay with 17" wheels (but in black). I've found a set of black OZ wheels I really like, but they aren't cheap. However, the 17" version is only 16.9lbs, which might help with all the stop and go in my typical driving. Decisions, decisions.

Oh, in case anyone else out there is considering how different colored wheels (or trim) might look, you should check out Plasti Dip in a spray can. Tons of videos on Youtube about how to paint your wheels/trim/etc with this stuff. Looks very professional, and if you don't like it you can just peal it off with no damage to your original finish. Not a permanent solution, but seems to hold up well and is a cheap and easy way to check out color changes.
 
TexaCali: The weight of the wheels will have an impact on your economy during city driving... OZ is usually pretty light.

I'm considering getting some non-LRR tires so I stop peeling out all the time.
 
Indeed, weight is a big reason I'm considering staying with 17" wheels (vs 18"). I haven't been able to find the weight of the stock wheels, and I don't have an accurate scale for that range (plus I would be weighing the tire, TPMS, wheel weights, etc), so I really have no idea how the weights would play out. That said, the 17's I'm looking at are 16.9 lbs each, which I'm guessing is significantly lighter than stock. Using 18's would place the wheel at 21.8 lbs AND increase the tire weight by 1 lb. That might still be lighter than stock, but I don't know.

Another consideration is I can keep the same tires with the 17's (at least until I get tired of them). The cost delta between 17's with my tires vs 18's with new tires (and new TPMS sensors) is about $1k! The only real reason for 18's would be looks, and the 17's would probably perform better in most aspects (acceleration, economy, ride comfort, etc).

If you find some non LRR tires that don't kill the mileage and improve traction, please let us know. I'm afraid it may be a choice between range and grip.
 
Update:

As you may know, the bolt pattern used by the Ford Focus (all current models, not just the FFE) is a 5-108, and this pattern is unique to the Focus and to some Volvo's. What this means is you won't find as wide a selection of wheels for the FFE as for some other cars. You should also know that the stock wheels are 17"x7" and have a either a 50mm or 55mm offset (I found conflicting information on the offset). The Focus ST uses 18x8 with a 55mm offset. Bigger offset means the wheels are closer to the center of the car and stick out less.

I wanted to find some wheels that were as light as possible while staying with the factory offset. I also wasn't going to purchase cheap made in China wheels, nor was I willing to pay $1k/wheel for exotic racing wheels. Ultimately I couldn't find any 17" wheels that met all of my criteria without a custom order (I did find some very nice wheels that came close, but offset was too low and I didn't want wheels sticking out and creating more drag). I did find some nice 18" wheels that were only 1lb heaver than the 17's, had the proper offset, were of high quality, and I liked the way they looked. I also read this article which claims wider wheels will actually reduce rolling resistance and improve economy even though wind resistance will increase slightly - http://www.barrystiretech.com/rrandfe2.html.

Bottom line, I have ordered a set of 18x8 rims (55m offset) that weigh 18 lbs each, along with sensors and tires (Primacy MXM4 235/40-R18). Once they arrive I'll report back with some photos, and then (eventually) some data on how they effect handling/comfort/economy. All I can say at this point is (based on the photo on Tirerack), the car will look much sportier, my wallet is is much lighter, and I still spent way less than a Tesla (and still don't have a Tesla). :eek:

Oh, and here is what Tirerack says it will look like:
car.jpg
 
Great choice - the 18s. The car will look very different.

On the ICE Focus, I have the 18s on during the summer - silver 5 spoke Ford wheels, unique to that car. During the winter I switch to 16s with snow tires. We chose black wheels with silver edges on them. The look is completely different.

I bought the TPMS reset tool at the time. Not sure it was absolutely necessary. Be sure to look up the TPMS pairing procedure (or maybe your dealer will do it for you) - it is a strange and complicated set of button presses.
 
Very cool, looking forward to the pictures..

I see a few ICE Focuses around here with some really slick looking wheels: All black with a geometric pattern on them. I can't seem to find them on Ford's website and on any other wheel website (almost looks like the ST wheels..but not quite). Oh its not like I'm going to put any on either of ours...
 
Thanks guys.

Looks like there is a minor wrinkle in my plan - the wheels are in Nevada but the Tires are in Connecticut. For some silly reason, TireRack can't ship the tires to Nevada, install, then ship to me. If I want the tires installed they are telling me it will be mid July! After a bunch of phone calls (including searching locally), tires and wheels will be arriving separately (with the tires taking about 10 days to get here), then I'll have to pay to get them mounted and balanced locally. Tire rack did eat a bunch of the shipping, but the net to me (after mounting) will still be $40 more this way - and take a little longer. Patience.... :roll:
 
Wheels are here, but looks like TireRack didn't ship the tires on Friday (though they did create a label). According to UPS site they actually shipped today (Tuesday) and won't get here until next Tuesday. In the mean time my "friend" has suggested we simply mount the rims and go run on the Union Pacific track! :lol:
 
Tires arrived today - but to late to get them mounted. Though it looks like I may have overlooked a critical parameter in my rolling resistance predictions - load rating.

The stock tires have a 93 load rating (650 kg). The argument about wider tires having lower rolling resistance is based on the assumption that wider tires are usually spec'd to carry a heavier load, but if the load stays the same then total force required to roll the tire decreases. Well, the replacement tires I ordered have a load rating of 91 (615 kg), so looks like I goofed. The Michelin Energy Saver series isn't available in anything lower than a 50 profile, so no chance getting these on 18" wheels with the FFE. The Primacy MXM4's in 235/40R18 have a 91 load rating, though I'm sure the compound and construction is different as well (even if they are both "Green X") so this never was going to be a scientific test. Unfortunately at this point in time there is no way for a consumer to determine how the rolling resistance of two tires will compare.

BTW - with regards to RR vs economy (or range in our case), I found this article - http://www.tirereview.com/what-will-tire-rolling-resistance-testing-prove/ If you go down about mid way, you will see they claim (for an ICE vehicle) that drag breaks down as follows:

Rolling resistance 15% (city) 25% (highway
Inertia 35%(city) 0%(highway)
Wind 5% (city) 60% (highway)
Driveline 45% (city) 15% (highway)

For an electric car, driveline drag is probably 5% of total drag for city and 1% on the highway, so if we re-scale the numbers we get RR at 25% of total for city and 29% for highway. That would imply a 10% change in RR would yield about a 3% change in range (assuming range is proportional to total drag). Then again I've seen Prius owners report a 10% MPG increase by changing tires - which by the above calculations would imply a huge (>30%) change in rolling resistance.

Well, I guess I'll find out soon when I mount these puppies up and see what happens to my range......
 
New wheels and tires were mounted and installed today. So far I am very pleased. It is too early to tell if there will be any significant change in range (the guess-O-meter still thinks I will get over 100 miles on a charge after a 32 mile spin - heavy traffic and AC use BTW), but the grip is much improved. No more wheel spin while trying to accelerate when pulling out of a driveway, and more importantly, cornering and braking in an emergency is no longer a concern.

New tires take a bit to break in and their rolling resistance typically improves after a few hundred miles, so I'll report back once they are broken in and I have some real data, but so far so good.
 
EVA said:
Why don't you use the size tires Ford uses as the summer tire (performance really) option for the ICE Focus?
235/40-18
They used this tire as optional equipment from Ford:
Michelin Pilot Sport 3

The PS3s are terrible performance tires. There are MUCH better options for less $$ on the market. Much of the Hankook line, etc.

EVA said:
At 100 MPH when the car lowered I didn't see the consumption go from 430 Wh/mile to 400 (not far off from what it uses at 100 MPH). There was no noticeable difference.

Curious, at ~60-65 MPH, what does the Tesla do for Wh/mi?
 
I just changed my wheels and tires on my 2014 FFE. I bought the Ford tpms trigger. Does anyone know the sequence to train/pair the new TPMS with the computer?
 
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