Tires

In the "Suspension Upgrades" topic, some of us have touched on tires as a way to improve handling and possibly mitigate torque steer. I'm starting this topic to dive deeper on tires.

Sparkie posted this great link to a vid showing what happens when you put good tires on a Leaf: http://www.youtube.com/watch?v=tOIAk8TA6b4

And he's looking at putting some Yokohama S.drives on his Spark. Has anyone else replaced the stock Eco tires with something else? If so, why and what was the effect?

The S.drive is billed as a summer tire. Where I live (Southern Oregon) we get a fair amount of rain and even some snow and ice in winter. I'd love a recommendation for a performance-oriented all-season tire.

This from a Car and Driver review of the Spark EV:

"Grip might be a concern. Our road test of the gas Spark returned a mediocre 0.79 g on the skidpad, and it's hard to imagine the low-rolling-resistance Bridgestone rubber on the EV will improve matters. Use the car's power freely, and the Spark EV seems to rely on electronic traction control more than mechanical grip."

I just put new Yokohama S. Drives on my Spark EV, and the improvement has been dramatic.

Accelleration from stopped: no wheel spin.
Turning and Accellerating: no wheel spin and significantly reduced torque steer.
Hard Braking: significantly improved.
Overall Road feel and confidence: significant gains.

Just had a heavy rain hear in NorCal, and the S. Drives performed very well. During a hard braking test there was no skidding or pulsing of anti-lock brakes. Went through a deep puddle pretty fast and the car felt light but I wasn't turning/braking so I don't know how good the traction was. Accellerating up a wet hill caused a little wheel spin.

I'm very happy with the new tires, and so is my wife. She was quite concerned about driving in the rain with the original Bridgestone Ecopias.

The only downside is a likely reduction in Range due to increased rolling resistance. Unfortunately we drive the car only ~20 miles per day and it is very inconsistent so I can't really give you a good metric for the range change with the new tires.

--Bob

From a Consumer Reports review of some all-season tires:

"Rolling Resistance
We only tested one performance all-season model marketed as a fuel saver—the Bridgestone Ecopia EP422—and it does indeed have low rolling resistance. However, we also found that the Michelin Primacy MXV4 H and Dunlop SP Sport 7000 A/S also have impressively low rolling resistance.

Braking on dry and wet pavement
Most tires stop well on dry pavement. The Falken Ziex ZE-912, Sumitomo HTR A/S P01, and the GT Radial Champiro VP1 get the nod for impressive dry stopping grip. On wet pavement, the Continental PureContact, Michelin Pilot Exalto A/S H, Dunlop SP Sport 7000 A/S, Sumitomo HTR A/S P01, and Yokohama Avid ENvigor are very impressive.

Handling
We provide a handling rating based on a weighted average of dry and wet cornering around our skid pad, subjective on-center steering feel, and emergency handling. Surprisingly, of the 20 H-rated models tested, there are no standouts. Most are capable, though we were unimpressed with the aforementioned Bridgestone Ecopia EP422. It just felt slower responding and gave up earlier in our handling tests than other tires."

It's a shame Chevy chose the Ecopias, since they appear to have the worst handling in this group of "performance all season" rubber, and there are better-handling all season tires with low rolling resistance. The Dunlop SP Sport 7000 A/S seems like a good choice, especially for wet climates.

Just thought I'd post this because I've also been contemplating different tires on the spark.

Unlike some of you, I come from performance cars, so I already know how much of a difference tires play in performance and driving feel. So with that in mind I slapped on some of my spare tires/wheels I had for another car. They are 21/45/16 Falken Azenis RT615's, on 16x7 Team Dynamics Motorsports wheels.

This is a summer only, street legal near R compound tire, meant more for autocross or track driving than anything else.




Not only did it change the way the car drove (steering was crisper, lateral grip was better less torque steer etc.) but the wider wheels fit the fenders better too IMO



The downside? Range. The wheel/tire combo weighed more than stock (36.6lbs stock vs 41.8lbs) so that meant more energy was needed to turn the tire, but the rolling resistance added a big part of hurting range too.

So normally during winter weather we are seeing around 3.2kwh on our normal trips to work. After installing the new tires, and then driving the same as I do going to/from work, that dropped to 2.3kwh. So that killed about 20ish miles of range off the total of the car.

For reference, not using the heater in the winter we were getting upwards of 4.4kwh on the same drive, so I'd put the tires up with the heater for range reduction.

Excellent informative post, thank you! Car looks great too.

Sweet! Thanks for the great info and pics.

Looks like there's a number missing where you wrote the tire size. Was that width of 21 supposed to be 215? Also, can you tell us what the width and offset of the rim are? Any clearance issues?

I'd really like to put wider tires on the stock rims because I don't want to spring for a whole new set. Do you suppose 205s would fit without creating a clearance issue?

Thanks for sharing! Looks like you went with identical wheels on all four corners? I'm also curious what offset you are running. Can you look at the factory wheels and see if they have the offsets marked on those? My car hasn't arrived yet and I can't figure out the factory offsets.

I'm hoping to fit some 949 6UL wheels for autocross purposes, so I'll be following a similar path soon.

Bryce

For future reference, this is the stock Spark EV wheel specs.

Front
15x6.0
ET45
Part number 95024486

Rear
15x6.5
ET54
Part number 95024487

Bryce

SenorChispa said:

Sweet! Thanks for the great info and pics.

Looks like there's a number missing where you wrote the tire size. Was that width of 21 supposed to be 215? Also, can you tell us what the width and offset of the rim are? Any clearance issues?

I'd really like to put wider tires on the stock rims because I don't want to spring for a whole new set. Do you suppose 205s would fit without creating a clearance issue?

Click to expand...

sorry, yes they are 215 width tires. Wheels are 16x7 et45. The offset requires a 2mm spacer due to clearance with the caliper and the rim. No rubbing issues.

I'm sure 205's wouldn't cause any clearance issues unless they were significantly taller than the stock tires.

Nashco said:

For future reference, this is the stock Spark EV wheel specs.

Click to expand...

Nashco said:

Thanks for sharing! Looks like you went with identical wheels on all four corners? I'm also curious what offset you are running. Can you look at the factory wheels and see if they have the offsets marked on those? My car hasn't arrived yet and I can't figure out the factory offsets.

I'm hoping to fit some 949 6UL wheels for autocross purposes, so I'll be following a similar path soon.

Bryce

Click to expand...

yes identical wheels on all 4 corners. Typically all FWD cars use this platform, and I"m betting the Spark EV is staggered only as a bandaid to the additional weight in the back and still trying to achieve the best possible mileage. Wider tires in the front and rear would solve any handling issues that arose from the change in weight distribution from using the platform as an EV.

Nashco said:

For future reference, this is the stock Spark EV wheel specs.

Front
15x6.0
ET45
Part number 95024486

Rear
15x6.5
ET54
Part number 95024487

Bryce

Click to expand...

Strange, I'll have to look again, but I could have sworn the wheel was the same front and rear when I pulled them off. I thought only the tire was a different width.

I've read somewhere here where a few people have replaced the stock tires with
Yokohama AVID Ascend's. I just got my new 2015 Spark EV last night and am wondering if I should get some of these, but I am hesitant to without checking on any negative range effects. I can't lose a mile's worth of range. One guy said he hadn't noticed any drop in kwh, implying, I guess, no range loss. Is this worth me doing?

Thanks for any input!

If range absolutely can't go down, use the stock tires. You won't do better on range with any other tires currently on the market that fit this car.

Bryce

Nashco said:

If range absolutely can't go down, use the stock tires. You won't do better on range with any other tires currently on the market that fit this car.

Bryce

Click to expand...

OK, great. Thanks for the advice. I'll take it.

Just a quick update, my Yokohama S Drive front tires wore out after 9,000 miles and 1.5 yrs.

When I was purchasing replacements, I discovered that the shop that installed the S Drives originally screwed up and put the 195s on the front rims and the 185s on the rear rims! I can't believe I drove for so long without noticing this error.

I had been having handling issues lately when it rains there is wheel slip on the front right tire followed by a loud clunk when the wheel regains traction. I took it in (for the hood latch recall) and had them look at it and all they said was the front tires are worn out. Even the dealer didn't notice tires were installed wrong!

Apparently the widths are close enough that the tires fit on the rims okay even when mismatched. Definitely something to keep an eye out for if you get new tires for your car.

--Bob

Bob,
Did the shop replace your tires for free then ?
Just curious as to what your resources were and if there was any kind of damage caused.

rbroders said:

Just a quick update, my Yokohama S Drive front tires wore out after 9,000 miles and 1.5 yrs.

When I was purchasing replacements, I discovered that the shop that installed the S Drives originally screwed up and put the 195s on the front rims and the 185s on the rear rims! I can't believe I drove for so long without noticing this error.

I had been having handling issues lately when it rains there is wheel slip on the front right tire followed by a loud clunk when the wheel regains traction. I took it in (for the hood latch recall) and had them look at it and all they said was the front tires are worn out. Even the dealer didn't notice tires were installed wrong!

Apparently the widths are close enough that the tires fit on the rims okay even when mismatched. Definitely something to keep an eye out for if you get new tires for your car.

--Bob

Click to expand...

tigger19687 said:

Bob,
Did the shop replace your tires for free then ?
Just curious as to what your resources were and if there was any kind of damage caused.

Click to expand...

They remounted the tires for free but I didn't hassle them for the premature wear on the fronts. I could've hit yokohama for warranty claim as well, but life is too short for that sort of nonsense. My resources allow me to buy a pair of new tires without sweating.

I've gotten just over 16K miles from the stock Ecopias on the front (thanks to keeping them at max cold sidewall pressure (44psi) and rotating regularly) but now it's time for them to be replaced. I'm looking at Pirelli's Cinturato P7 All Season (the only model of the line available in 185/55R15 size) which is estimated to return slightly better efficiency than the Yokohama Avid Ascends by BigBrandTire.com but the Ascends are a notch better in every other category, less expensive, and come with a treadwear warranty. (Only the P7 All Season Plus does but that doesn't come in this size.) So I'm shortly going to join you that have Ascends.

Update: I've had the Ascends on the front since my last post and have noticed that they definitely affect the range. I've noticed roughly 10-15 miles of range loss and a trip average of 4.4mi/kWh (compared to 5.0) since the new tires. (I have all tires at max cold sidewall pressure: 51psi for the Ascends in the front and 44psi for the Ecopias in the rear.) This has caused us to have to take the gas car for one of our longer weekend trips so far (because we weren't going to be at any destination for long enough to charge enough at 3.3kW to return,) so now I've got more motivation to install (a) booster charger(s). I'll post more about that in another thread.