rejedejo
Posts: 5
Joined: Tue Mar 20, 2018 2:44 pm

NON OEM wheels & tires (wider)

Tue Mar 20, 2018 3:57 pm

Has anyone set up their i3 with non-OEM wheels & tires?

I understand the specs are:
Bolt pattern (PCD): 5 × 112
Center Bore (CB): 66.7
Thread size (THD): 14 × 1.25
Diameter: 19 — 20
Width: 155
Aspect ratio: 60 — 70
Offset 43mm

For example: 215X50X18s would be .93 - .96 as big diametrically and 1.23-1.39 wider.
Has anyone used non-standard wheels & tires on these?
Trading some range for performance & tire life?
:?:

sipabit
Posts: 106
Joined: Sun Mar 04, 2018 2:01 am

Re: NON OEM wheels & tires (wider)

Thu Mar 29, 2018 10:43 pm

You won't really get better performance as any other rim will weigh more even if it enables a wider tire.
A fanatic of all things electric. Ridables like electric ice chests and stand up scooters I adore. Drones like DJI, I root for. I'm a fan of both, but nothing beats my love for my 2016 i3 Rex with Deka World. Shhh, don't tell my wife.

rejedejo
Posts: 5
Joined: Tue Mar 20, 2018 2:44 pm

Re: NON OEM wheels & tires (wider)

Fri Mar 30, 2018 5:32 am

Hmm. Tire rack reviews complain about tire life, Reviews in general note that there’s just not enough rubber on the road contributing to long braking distances and sliding around corners. 15,000 miles is long life for the ecopeia tires, a set delivered and installed ~$650. That’s about $.043/mile. More than the fuel to run the car. Seems like someone would swap them out. Maybe with some 205-50x17s. Drop the car an inch and get some 10% better acceleration.

I doubt 17” rims would be much heavier

jadnashuanh
Posts: 4488
Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: NON OEM wheels & tires (wider)

Fri Mar 30, 2018 6:26 am

The i3's wheels are forged, and as a result, tend to weigh less and be stronger than a typical cast wheel.

The reason why BMW chose the tall tires is that that means the actual tire patch on the road for acceleration and braking is about the same as a smaller/wider tire in the same rolling diameter. IOW, going smaller/wider won't give you more tire patch, just orient it differently. And, in the process, create more drag and potentially impact the fender or give you problems with the clearances at max steering angles. Keep in mind that the i3 has a pretty small turning radius, and to get that, the tires turn more than many other cars (especially front-wheel drive ones since the CV joints tend to limit the available range).

A wider tire will have more drag.

Unless the overall diameter is the same, the speedometer and odometer will not be accurate. A smaller diameter assembly may LOOK like you're accelerating faster, but probably not. Plus, the stability control will likely limit that to prevent wheel spin, so you may not gain much of anything. A wider one could give you a bit more lateral grip as the tire patch would be wider (but shorter), so oriented more for turning capability verses acceleration and braking.

A wider tire, in general, won't handle rain or snow conditions as well as a narrower one.

Tread depth also impacts the rolling resistance as it gets deeper, so the as new depth may be a bit shallower, and that does affect their life. Deeper tread tends to squirm a bit more, increasing the rolling resistance and generating more heat, which also affects the design of the rubber compound. Lots of tradeoffs/optimizations. You can improve one aspect, but likely would diminish another when you play around. You might get the mix better tuned to your preferences, but may not like the consequences.
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV

rejedejo
Posts: 5
Joined: Tue Mar 20, 2018 2:44 pm

Re: NON OEM wheels & tires (wider)

Fri Mar 30, 2018 3:43 pm

I don’t disagree mostly:
though if diameter ~90% then acceleration ~110%

Agree on the odometer & speedometer discrepancies

Agreed about the wheels rubbing on the chassis or suspension have to make sure isn’t a problem.

Do you agree that the current tires wear out fast?

Do you think a single tire is a good option?

Wondering if anyone has done it. Wondering why no one has.

jadnashuanh
Posts: 4488
Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: NON OEM wheels & tires (wider)

Fri Mar 30, 2018 4:31 pm

Tire life is sometimes hard to estimate. One thing against long life with the i3 is that it has a lot of torque for the overall weight of the vehicle, and the electric motor is somewhat addictive, and people probably tend to use it more than they might on other vehicles, leading to lower life.

There are people that achieve significant distance on their tires on the i3, and then, there are others that are disappointed. One thing that could be an issue is if it is out of alignment. I swap my all-season tires for winter tires, so I get a close-up view of them at least a couple of times a year. Last time, it was obvious that the alignment was off. I had it realigned. It's a bit difficult to say when I'll need to replace mine.

Generally, car manufacturers like to have at least two different vendors for things like tires. It appears that they were not able to entice another company to build them for the i3. Nokian does offer a winter tire option, but, at least last I looked, they do not have any other tires that are direct replacements. EVs are popular in Scandinavia, and Nokian does make good winter tires!

BMW didn't pull many punches with the i3, and that included getting someone to build a tire that would aid its mission - efficiency.

If your tire/wheel assembly has a smaller overall diameter, it will look like you're going faster, but it's like lowering the gear and then revving the motor, requiring more revs to go anywhere. MOre wear, more noise (not as much as you might get in an ICE), and likely more energy use.
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV

rejedejo
Posts: 5
Joined: Tue Mar 20, 2018 2:44 pm

Re: NON OEM wheels & tires (wider)

Sat Mar 31, 2018 11:01 am

And: more available thrust per torque and lower CG for even better handling. The tires cost more than the energy per mile, so if you halve your tire cost and halve your range you come out even.

I don’t have an i3, I am in line for a Tesla3, but used i3s are looking like a good value proposition if something could be done about the tires.

alohart
Posts: 1676
Joined: Sat Nov 01, 2014 7:36 pm
Location: Honolulu, HI

Re: NON OEM wheels & tires (wider)

Sat Mar 31, 2018 12:17 pm

To maximize interior space, an i3 has very little fender space in which to install wider wheels and tires. The 1/2" wider wheels and tires of the i3S was accomplished using wheels with greater offset and by the installation of fender flares.

Automobile magazines that tested the i3 reported an excellent braking distance, not poor braking that you allege. Good front-rear weight distribution and a low center of gravity make the i3 a decent performer when cornering.

Concerning tire wear, different i3 owners have reported much different experiences with a few owners reporting up to 40k miles of tire life while others, likely running the 20" summer tires rather than the all-season tires that have been available in both 19" and 20" sizes, have reported rear tire life as low as 10k miles ignoring cases where incorrect wheel alignment caused more rapid tire wear. Instant torque results in many i3 drivers using it frequently which, coupled with strong regenerative braking applied only to the rear tires, can result in rapid rear tire wear. BMW M car owners tend to wear out their much more expensive performance tires, so the tire wear rate reflects the driver's behavior.

My feeling is that you are more concerned about an i3's tires than most owners who have experience with these tires. But if you insist on installing wider tires on an i3, you're probably looking at the wrong car.
Aloha,
Art

2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

bwilson4web
Posts: 705
Joined: Fri Apr 29, 2016 11:59 pm
Location: Huntsville, AL

Re: NON OEM wheels & tires (wider)

Sun Apr 01, 2018 3:04 am

So after 24k service miles, BMW reports the tread depth is 5 mm for all four tires. They fixed the slow leak and report all of the tires look to have even wear.

Bob Wilson
20k/27k mi 2014 BMW i3-REx
10k/10k mi 2017 Prius Prime

alohart
Posts: 1676
Joined: Sat Nov 01, 2014 7:36 pm
Location: Honolulu, HI

Re: NON OEM wheels & tires (wider)

Sun Apr 01, 2018 11:47 am

bwilson4web wrote:So after 24k service miles, BMW reports the tread depth is 5 mm for all four tires. They fixed the slow leak and report all of the tires look to have even wear.
The results of your earlier alignment experiments seem to be working well. Please remind me what alignment settings you are using.
Aloha,
Art

2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

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