Help Support Chevy Spark EV Forum:
nikwax
Well-known member
Zoomit said:
195's all around
I swapped out mine after only a few weeks of ownership.
I'm saving the original tires (with ~3500 miles on them) and will use them at a later date. I just did my first tire swap a little early...
It's not like you are wasting a perfectly 'good' set of tires.
You are just going for 'instant gratification',, and having 'performance' tires on this little EV Hot Rod is 'Gratifying' !!
I now wish I had gone 195 all around....
Traction control is still keeping the fronts from spinning, good !
But with bigger stickier tires I suspect 0-60 times are probably a little better.
Anyone?
I'm saving the original tires (with ~3500 miles on them) and will use them at a later date. I just did my first tire swap a little early...
It's not like you are wasting a perfectly 'good' set of tires.
You are just going for 'instant gratification',, and having 'performance' tires on this little EV Hot Rod is 'Gratifying' !!
I now wish I had gone 195 all around....
Traction control is still keeping the fronts from spinning, good !
But with bigger stickier tires I suspect 0-60 times are probably a little better.
Anyone?
nikwax
Well-known member
Here's my energy data, running 44 psi (max):
drive across town, some uphill, 5.1mi/kwh
drive back, some downhill: 5.7 mi/kwh
drive across town, some uphill, 5.1mi/kwh
drive back, some downhill: 5.7 mi/kwh
We can't really use that data for comparison. It needs to be same route, traffic, speed and weather to really assess the differences between tires. I'd guess the efficiency differences between the OEM tire and others is about 5%. Yet on my commute, I can see a 50% difference in energy usage just due to speed, traffic and headwind.
Put another way, you could decrease your average speed relatively easily to make up for the difference in rolling resistance between tires. For example, you might drive 5 mph slower on the highway with high performance (less efficient) tires but you could get the same net energy usage over trip as the low rolling resistance Ecopia OEM tires at a higher speed.
Traffic factors in as well. A highway drive with moderate traffic can be more efficient due to the collective wind created by the vehicles and you'll see reduced aero drag even without drafting/tailgating. With no traffic, more energy is used.
I see the combined effects of traffic and speed all the time on my commute. Traveling the same speed and no winds my efficiency will vary from 5.4 to 6.4 mi/kWh. (Note these great numbers are due to the 1000' elevation change.) I attribute most of this variability to whether I'm close to other vehicles or not. If I bump up the speed by 5 mph, by efficiency decreases and will vary from 5.1 to 6.1 mi/kWh, a typical loss of 5% over the slower speed. If I bump up the speed by 10 mph, my efficiency varies from 4.6 to 5.6 mi/kWh. That's a loss of 13% over the original speed. (It's more than 10% because drag rises as function of velocity squared: Fd=1/2*rho*V^2*A*Cd)
So, in summary, drive 5 mph slower with your sticky tires and you'll use the same energy as OEM tires to get somewhere. Alternatively, you can drive safely behind someone in traffic (no need for close drafting) with your sticky tires and you'll also use the same energy as OEM tires with no traffic to get somewhere.
Put another way, you could decrease your average speed relatively easily to make up for the difference in rolling resistance between tires. For example, you might drive 5 mph slower on the highway with high performance (less efficient) tires but you could get the same net energy usage over trip as the low rolling resistance Ecopia OEM tires at a higher speed.
Traffic factors in as well. A highway drive with moderate traffic can be more efficient due to the collective wind created by the vehicles and you'll see reduced aero drag even without drafting/tailgating. With no traffic, more energy is used.
I see the combined effects of traffic and speed all the time on my commute. Traveling the same speed and no winds my efficiency will vary from 5.4 to 6.4 mi/kWh. (Note these great numbers are due to the 1000' elevation change.) I attribute most of this variability to whether I'm close to other vehicles or not. If I bump up the speed by 5 mph, by efficiency decreases and will vary from 5.1 to 6.1 mi/kWh, a typical loss of 5% over the slower speed. If I bump up the speed by 10 mph, my efficiency varies from 4.6 to 5.6 mi/kWh. That's a loss of 13% over the original speed. (It's more than 10% because drag rises as function of velocity squared: Fd=1/2*rho*V^2*A*Cd)
So, in summary, drive 5 mph slower with your sticky tires and you'll use the same energy as OEM tires to get somewhere. Alternatively, you can drive safely behind someone in traffic (no need for close drafting) with your sticky tires and you'll also use the same energy as OEM tires with no traffic to get somewhere.
nikwax
Well-known member
Yeah, that wasn't a scientific test. I could have added that based on very limited experience, those numbers are very similar to the OEM tires, perhaps even better, certainly no worse. I might have expected to see a significant drop in usage, but I'm perfectly happy with the results.
I'm after excellent grip in all conditions. I'm willing to give up some range to get it. And I'm happy with how little range I've apparently given up.
I'm after excellent grip in all conditions. I'm willing to give up some range to get it. And I'm happy with how little range I've apparently given up.
Curyousgee
Active member
- Joined
- May 28, 2015
- Messages
- 28
Took mine thru Santiago canyon and it handled very well, was impressed
nikwax
Well-known member
we had some heavy rain recently, so I got to experience freeway driving through standing water. No issues at all. Impressive wet and dry handling so far. The high center of gravity / narrow track is noticeable vs the WRX or C30, but as a punymobile the Spark handles very well indeed.
suparukuibi
Member
- Joined
- Sep 4, 2015
- Messages
- 13
The handling is hurt by FWD, soft suspension, and crappy LRR tires.
The handling is helped immensely by the small, light package.
And the torque is great when pointed straight forward.
The handling is helped immensely by the small, light package.
And the torque is great when pointed straight forward.
