Upgrading to Larger Wheel/Tires

[Energized]

Has anyone determined if the 225/50R17 standard wheel/tire combo can be upgraded to 235/45R18 without affecting the speedometer, ABS etc?

[meyersnole]

did a search for a tire diameter calculator which says you new tire would be larger making the speedometer too slow by 1.822%

 

and the closest you can find would be 285/35R18

 

http://www.1010tires.com/tiresizecalculator.asp

 

Not sure if there are any other adverse affects of changing to that size but your tire store could tell you. (Turning radius, etc)

[shaggy314]

Look at the specs for the hybrid's 18". Surely it would be trivial to reprogram the car to exactly match them.

 

EDIT: And really there isn't much as the whole idea is to match outer tire circumference. Maybe TPMS or changes in wheel weights or what have you...

Edited February 28, 2013 at 05:08 PM by shaggy314

[Energized]

did a search for a tire diameter calculator which says you new tire would be larger making the speedometer too slow by 1.822%

 

and the closest you can find would be 285/35R18

 

http://www.1010tires.com/tiresizecalculator.asp

 

Not sure if there are any other adverse affects of changing to that size but your tire store could tell you. (Turning radius, etc)

 

Thanks for the calculator.  I noticed at the bottom of that web site it says:

 

"When changing tire sizes, we recommend staying within 3% of the diameter/height of the original tire. Any more than this and you face the risk of brake failure."

 

So going from the standard 17s to the factory 235/45R18 would theoretically be okay

[meyersnole]

Thanks for the calculator.  I noticed at the bottom of that web site it says:

 

"When changing tire sizes, we recommend staying within 3% of the diameter/height of the original tire. Any more than this and you face the risk of brake failure."

 

So going from the standard 17s to the factory 235/45R18 would theoretically be okay

 

Maybe.

 

I find it odd that there are no wheel options for the energi. I would want to talked to a trained mechanic first.

 

Unsprung weight can have a significant affect on performance, even if the speedometer is not affected. You will lose efficiency going to the 18s. There is also a significant jump in price for that tire size (the 18s)

[shaggy314]

Maybe.

 

I find it odd that there are no wheel options for the energi. I would want to talked to a trained mechanic first.

 

Unsprung weight can have a significant affect on performance, even if the speedometer is not affected. You will lose efficiency going to the 18s. There is also a significant jump in price for that tire size (the 18s)

Why is it an option for the hybrids? I know the Energi is heavier so they try to save every ounce, but a simple "* may effect fuel mileage", and let us get the 18" sports. I'm sure they offer 18" low rolling resistance tires right? Edited February 19, 2013 at 08:51 PM by shaggy314

[pluggedin]

I really would like the Y spoke wheels, but they are not offered by Ford on this model. If I really hate the wheels that come with the car I may try to find something I like in the after market but I will not change the size of the wheel. The 17" wheel that comes with the car is 2" bigger then I have on my car now and I do not want to mess with my miles per gallon stats.

[meyersnole]

I have only changed the wheels on my car once in the past. I had a 1997 BMW 528i that had 15" wheels and I put on 17s. I ended up losing about 2 MPG in addition to firming up the ride considerably. I learned a lot with that experience though, the main reason you lose gas mileage is mostly weight, not diameter of the rims. The overall size of the tire does not really change. You need to pay attention to the total weight, both the tire and the rims.

 

The other additional cost came from the increased cost of the tire. Depending on the size it can be considerable. When I look for the above size, 285/35/R18, I only find one tire that is low rolling resistance https://www.tirerack.com/tires/tires.jsp?tireMake=Michelin&tireModel=Pilot+Sport+3&partnum=835YR8PS3XL&vehicleSearch=false&fromCompare1=yes  at about 3 times the cost of the EOM tires.

[shaggy314]

I PLUS-1 my Integra (14" -> 15") and you can see her mileage below... not too shabby @ 215,000.

[yojroz]

My dealer told me he could switch my wheels with any one they offer on the Fusion despite it not being an option.  I just have to decide if I think it's worth it or not.

[Energized]

These wheels are the best looking on the Fusion I think

 

     19" Y-spoke Sparkle Silver-painted aluminum wheels with machined face and 245/40R19

 

But they're probably too big of a size increase from the standard 225/50R17

[yojroz]

These wheels are the best looking on the Fusion I think

 

     19" Y-spoke Sparkle Silver-painted aluminum wheels with machined face and 245/40R19

 

But they're probably too big of a size increase from the standard 225/50R17

I completely agree.  Wonder how badly that would affect the mpg's?

[Energized]

It's not so much the reduced although it would inactive that, it's more the impact on the abs brakes and stability control and perhaps some hybrid related sensors due to a different tire circumstance than what the computers are expecting.

[meyersnole]

Actually Energized, the circumference remains the same, but the unsprung weight and reduced sidewall of the tire will greatly impact the the way the car drives / feels.  The car will rid more firm and acceleration will also slow. Steering and cornering will generally feel more controlled.

 

There should be no affect to the speedometer accuracy, but I am not sure about braking. I would think that would be minimal if noticeable at all. Gas mileage will drop. given some of the conversation on the other forum from the people who put the bigger tires on their hybrid, it could be substantial.

[FusionEnergi]

I agree with Meyersnole. Also if your buying the energi it's gotta be mostly for the mileage. Could it void the cars warranty?

[yojroz]

Interesting though that bigger wheels are offered on the Hybrid but not the Energi.  I wouldn't think it would void the warranty and it shouldn't affect the fuel mileage that much if it's being offered.  There's no mpg difference listed on the Hybrid SE with 17" vs the Hybrid Titanium with 18".

[pluggedin]

There's no mpg difference listed on the Hybrid SE with 17" vs the Hybrid Titanium with 18".

Maybe not, but if you look at the other forums you will note that those who are complaining of poor, or terrible, fuel mileage have the bigger wheels.

Edited February 25, 2013 at 03:18 AM by pluggedin

[Energized]

Actually Energized, the circumference remains the same, but the unsprung weight and reduced sidewall of the tire will greatly impact the the way the car drives / feels.  The car will rid more firm and acceleration will also slow. Steering and cornering will generally feel more controlled.

 

There should be no affect to the speedometer accuracy, but I am not sure about braking. I would think that would be minimal if noticeable at all. Gas mileage will drop. given some of the conversation on the other forum from the people who put the bigger tires on their hybrid, it could be substantial.

 

 

Actually tire circumference would increase if changing out to the larger factory wheels (C=3.14 x diameter) and  it would therefore  impact the speedometer accuracy. 

 

Factory 17s vs factory 19s which is a 3.32% difference. 

 

Tire Diameter Inches Tire Circumference Inches  25.858 D  81.235 C

 

Tire Diameter Inches Tire Circumference Inches  26.717 D  83.934 C

Edited February 26, 2013 at 12:13 AM by Energized

[meyersnole]

interestingly enough it is off, but according to 1010tires not by 3.32%

 

If the sizes are 235/50 R17, 235/45 R18, and 235/40 R19 then

 

235/45 R18  Speedometer Difference: 0.265% too slow, Diameter Difference: 0.27%  ( R17 speedo = 60, R18 speedo = 59.8 )

 

235/40 R19 Speedometer Difference: 0.571% too slow, Diameter Difference: 0.57% ( R17 speedo = 60, R19 speedo = 59.6 )

[Energized]

interestingly enough it is off, but according to 1010tires not by 3.32%

 

If the sizes are 235/50 R17, 235/45 R18, and 235/40 R19 then

 

235/45 R18  Speedometer Difference: 0.265% too slow, Diameter Difference: 0.27%  ( R17 speedo = 60, R18 speedo = 59.8 )

 

235/40 R19 Speedometer Difference: 0.571% too slow, Diameter Difference: 0.57% ( R17 speedo = 60, R19 speedo = 59.6 )

 

Your figures are incorrect.  You aren't using the standard factory tire sizes. 

 

The figures I posted are correct.

 

81.235 x 1.0332 = 83.93    A 3.32% error means  65 mph indicated is actually 67.16 mph, but more importantly "When changing tire sizes, we recommend staying within 3% of the diameter/height of the original tire. Any more than this and you face the risk of brake failure."   Thereofre, the factory 19s would not be a choice to swap out.

[meyersnole]

Could not find the tire sizes on the Ford site so I used the ones that Tirerack.com said were the factory tire sizes.

[Energized]

I found this warning in the Owners Manual in the Adaptive Cruise Control section:

 

Do not use tires sizes other than

those recommended because this

can affect the normal operation of

the system. Failing to do so may result in

a loss of vehicle control, which could result

in serious injury.

[Scooter80]

I'll be interested in seeing if the ford brochure Energi size of 225/50-17 is a misprint or not. Most if not all other Fusion trims have a tire size with ~766 revs/mile. According to the brochure, the Energi's tire has 780. Just seems a little off to me. Especially when tirerack.com shows the stock tire being a 235/50-17. I get that a thinner tire would have less rolling resistance, making up the MPGe due to the heavier battery pack, but won't the diameter change this figuring as well? Anyone have their Energi yet to verify this? I'm hoping mine is here this week! Not looking too forward to the small, sort of ugly wheels, but I'll live.

[meyersnole]

For me, 17 inch is just fine, but they could have picked nicer rims. In addition to looking like the will be a PITA to clean they don't look that great either. I would have liked either the Y or H style rim in 17.

[DelS]

Your figures are incorrect.  You aren't using the standard factory tire sizes. 

 

The figures I posted are correct.

 

81.235 x 1.0332 = 83.93    A 3.32% error means  65 mph indicated is actually 67.16 mph, but more importantly "When changing tire sizes, we recommend staying within 3% of the diameter/height of the original tire. Any more than this and you face the risk of brake failure."   Thereofre, the factory 19s would not be a choice to swap out.

But if this were true, which I hope it isn't, there would not be an option for 19's on the Titanium non-hybrid, no?  Suspension/braking system are the same between the non-hybrid and NRG?   Or is it a weight thing?