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Discussion Starter #1 (Edited)
We just did a 0-60 mph comparison test of the Bolt with 16" X 6.5" Cruze OEM mags, with the Bridgestone Potenza RE71 205/45 series tires mounted, versus the oem stock wheels and tires. These rims weigh about 19-20 pounds, so may be several pounds lighter than OEM ones.

The results, after several runs averaged, was that we cut the time by better than 0.25 seconds. which is excellent. I figure the difference in times is more important than the actual time obtained, as conditions and cars always differ. We ran the car to an indicated 65 mph for the Potenzas, to make up for the 8% lower gearing. Times were taken with an Accusplit timer, which only those who raced in the '60s would be familiar with. Look it up on Google.

We turned off traction control for both sets of runs, to be consistent, but left stability control on. Interestingly, even the OEM tires only chirped a small amount, due to the clean dry concrete highway we tested on, (from a stop light, so no laws were broken, or even stretched) And even with the lower gearing, the Potenzas had more grip than needed, as there was absolutely no trace of wheel chirp.

So, Mr. Tavel, thanks for doing a superb job on the Bolt suspension and handling. We are quite pleased.

On the handling issue, we added a prototype 3/4" hollow tube sway bar to the back suspension, and will be evaluating that at an autocross Sunday. I will try to add a comment here by afternoon. (California time) Preliminary skid pad tests indicate a larger one would probably be better, and the materials are ordered to make the next version.
 

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Awesome! Thanks for the info. I was really hoping to see a slightly better 0-60 improvement with different tires, but I'm sure more data will come.
 

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Discussion Starter #3
If someone would make a lower profile tire (like a 235/35 series) for a 16" wheel, we could do even better. (grin)
 

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Heh. I'm looking at some rim/tire options, but I don't feel like I have the best equipment for testing 0-60 mph times. If you're interested, I'd be down to meet up and test some time. I was actually just driving through Fresno yesterday before friends and family told me to turn around. :p

So you think 235s will run on the Bolt EV? I'd think they would be a bit wide for the wheel well. I was looking into some 225/55R16 options on 16x7 rims. I'd like to preserve the OD for speedometer and mileage sake, and that seems like a good balance between traction and weight (it would likely drop about 7 lbs per corner).
 

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RE: your timing, just curious if you've explored some of the apps available for 0-60 timing? I know I've used some of them and they appear to be pretty accurate using GPS.
 

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Discussion Starter #6 (Edited)
Actually, 215/55 or 225/50 would fit better, for 17" oem diameter, the 235s would only work if ultra low profile (235/35s, in other words) Otherwise, yeah, too wide a sidewall, and might be very difficult to even get on the rims.

The autoX we are going to tomorrow is over at Marina on the coast. But I think it is a pre-register only event.
It is 144 miles one-way, so I am hoping some DC chargers in Salinas, and in Madera are working for the trip back. (grin) :)
 

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Thanks for sharing...You went from LRR with extra weight from the self-sealing to summer only RE71 so big change there...Generally downsizing one or two inches and lighter weight works...Would love to see if 15s could fit but the Bolt has a somewhat uncommon bolt diameter, hard to find light weight wheels cheap...Unless someone wants to be the first to redrill hubs to a more popular size may need to spend the big bucks on light rims...

Heh. I'm looking at some rim/tire options, but I don't feel like I have the best equipment for testing 0-60 mph times. If you're interested, I'd be down to meet up and test some time. I was actually just driving through Fresno yesterday before friends and family told me to turn around. :p

So you think 235s will run on the Bolt EV? I'd think they would be a bit wide for the wheel well. I was looking into some 225/55R16 options on 16x7 rims. I'd like to preserve the OD for speedometer and mileage sake, and that seems like a good balance between traction and weight (it would likely drop about 7 lbs per corner).
Just an FYI you probably already know this, be sure you are including the weight both of the wheels and tires, not just the wheels...Possible could the exact same weight between OEM and these...You might be surprised at the difference of simply just getting summer only tires without change the rims...Many places in L.A. sell and install used tires fairly cheap...
 

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Discussion Starter #8
Actually, I just realized that the Fiero bolt pattern matches the Bolt one. And the GTs came with 15" wheels. If I get time later on, I might just try some, and see if they clear the calipers, etc. It might be a really tight fit.
 

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Actually, 215/55 or 225/50 would fit better, for 17" oem diameter, the 235s would only work if ultra low profile (235/35s, in other words) Otherwise, yeah, too wide a sidewall, and might be very difficult to even get on the rims.

The autoX we are going to tomorrow is over at Marina on the coast. But I think it is a pre-register only event.
It is 144 miles one-way, so I am hoping some DC chargers in Salinas, and in Madera are working for the trip back. (grin) :)
Madera was online yesterday, but it's only 100A. Might be good to top up to 85% before heading out. I haven't used the Salinas charger, but Gilroy outlets does work (also, only 100 A).

Just an FYI you probably already know this, be sure you are including the weight both of the wheels and tires, not just the wheels...Possible could the exact same weight between OEM and these...You might be surprised at the difference of simply just getting summer only tires without change the rims...Many places in L.A. sell and install used tires fairly cheap...
Yeah. We still need to get the OEM tires separated from the rims. The total weight for the stock LT rim and tire was ~45.5 lbs. According to TireRack, the OEM tires are only 21 lbs. I find that hard to believe, and some have stated that they don't think TireRack was including the internal sealant. The Volt's (non-sealant) tires weigh 21 lbs as well, so that's a possibility. It's hard to image that the stock rims plus TPMS weigh 24 lbs.

I was actually looking at an aftermarket rim + tires, which would come in at 38-39 lbs, so worst case scenario, -6 lbs. You're right, though. Swapping out for summer performance tires even on stock rims could save ~ 3 lbs, but being 6.5", I wouldn't want to go wider than 215.

Actually, I just realized that the Fiero bolt pattern matches the Bolt one. And the GTs came with 15" wheels. If I get time later on, I might just try some, and see if they clear the calipers, etc. It might be a really tight fit.
Let us know. I'd still rather have 16" or 17", but this 5x105 PCD is killing me!
 

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Discussion Starter #10
I bought those used Cruze OEM mag wheels off ebay for about $65 each. And probably every junkyard in America has more of them. Also, a lot of compact or intermediate Pontiacs, buicks and Chevys might be the same size bolt pattern, at least the American built ones.
 

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Actually, I just realized that the Fiero bolt pattern matches the Bolt one. And the GTs came with 15" wheels. If I get time later on, I might just try some, and see if they clear the calipers, etc. It might be a really tight fit.
One of my car buddies, who is a rabid Fiero fan, says all years of Fiero are 5x100. Volt (G2)/Cruze/Bolt is 5x105.
 

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If you are trying for maximum performance make sure the battery is near fully charged. According to various GM documents, power output is reduced somewhat at lower battery charge. You probably should keep the battery charged above 75% to get the best numbers.
I was watching some videos at one point of a Model P100D at the drag strip, and the owner was saying that quarter mile times suffer with even a small dip below 100% SOC. Basically, every kWh counts.

And that makes sense why GM advertises the Bolt EV as having a 0-60 mph time of less than 7 seconds, yet Motor Trend's test clocked it in at 6.4 seconds. GM doesn't want someone taking the Bolt EV out at 60% SOC and complaining about how slow its acceleration is (or how far below advertised).
 

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We just did a 0-60 mph comparison test of the Bolt with 16" X 6.5" Cruze OEM mags, with the Bridgestone Potenza RE71 205/45 series tires mounted, versus the oem stock wheels and tires. These rims weigh about 19-20 pounds, so may be several pounds lighter than OEM ones.

The results, after several runs averaged, was that we cut the time by better than 0.25 seconds. which is excellent.
So what was the total time that you got? Motor Trend says they got 6.3 seconds 0-60mph and 14.9 for the quarter mile which is pretty good with stock tires. Others say 6.5 seconds 0-60.

http://www.motortrend.com/news/chevrolet-bolt-ev-2017-car-of-the-year/

It is not recommended to go higher than 3% on the difference in overall diameter. I would have gone with 205/55/16 since it is less than 3% difference. I would have gone with 16x8 lightweight wheels. Those are around 15 pounds from Eikei, Sparco, OZ, etc... and put 225/50/16. You will get even better acceleration, but much better handling, especially in autox.

On tirerack they give 23lbs tire weight for 225/50/16 Potenza re71. With a 15lbs wheel you would end up with 38lbs total. Pretty much the same thing as what you have now with 205/45/16.
 

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So what was the total time that you got? Motor Trend says they got 6.3 seconds 0-60mph and 14.9 for the quarter mile which is pretty good with stock tires. others say 6.5 seconds 0-60.

http://www.motortrend.com/news/chevrolet-bolt-ev-2017-car-of-the-year/

It is not recommended to go higher than 3% on the difference in overall diameter. I would have gone with 205/50/16 since it is less than 3% difference. 205/55/16 is 1.09% difference. I would have gone with 16x8 lightweight wheels. Those are around 15 pounds from Eikei, Sparco, OZ, etc... and put 225/50/16. You will get even better acceleration, but much better handling, especially in autox.
Those wheel makers are good, but so far, only Enkei has 5x105 PCD. And they don't offer that bolt pattern in their lighter rims. If they made 16" or 17" RPF1s in 5x105, I would buy them today.
 

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If you encounter "bog" exiting tight sections like Volt does, the trick is to find the Throttle Position Sensor threshold and do not exceed it.

What happens in the Volt, if you turn off the TC and Stability Control (or leave them on), and nail the brakes before a corner, then floor it on exits, if the body is leaned over, it will delay full power output. Essentially, on a Volt it cannot be turned off.

So you trick it. Trail brake into the corner, then gently roll the throttle in when the body roll starts to come back on exiting. It will haze the fronts on the exit and not bog. The difference? 78.xxx to 73.111. I could never break 76 seconds by nailing where I would a Corvette on exits. Only by driving like I was on ice could I drop the times.
 
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