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2014 Volt with 20" Wheel and Tire Package

8980 Views 13 Replies 13 Participants Last post by  DAFTEK
I searched for a while for a 20" package that could be applied to the Volt and not add a ton of weight. Most of the lighter wheels were designed to be used on race cars and were therefore not as visually appealing as I'd prefer. The other custom wheels that kept the weight low were usually extremely expensive. Ultimately, I decided to go with the Rotary Forged line of wheels offered by TSW. Additionally, TSW will custom drill the wheels to 5 x 115, which is the factory spec bolt pattern for the Volt. This eliminates the need or risk of applying slightly out-of-spec 5 x 114.3 wheels to the Volt. TSW also provides hubcentric rings with their wheel packages to ensure a smooth ride.

The package that I went with is a TSW Bathurst 20" x 8.5" with a 40 mm offset. The tires are Continental Extreme Contact DWS in a 245/35-20. I didn't place the new setup on a scale prior to installing them but the specs state that they should weigh 45 - 47 lbs each. I have weighed my factory wheel and tire combo and they weigh 38 lbs each. So far, I have seen no obvious loss of range with the new setup. However, it's too soon to tell, as it has only been a few days.

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jsten,
The new wheels look very nice. And I don't think you can go wrong with the set-up you've described. ELR uses 245/40R-20 size. This page doesn't show the details of wheel offset:
http://media.gm.com/media/us/en/gm/.../Jan/13naias/elr/0115_elr_specifications.html

I'm surprised the ELR wheels are not forged wheels as Volt wheels are. I've been very happy with ELR's range so far - I've had it for 3 weeks and ~1,500 miles on the odometer, and I'm already seeing 52 ~ 53 miles per charge (driver only, no A/C use).
 

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My question is why? Why 20" wheels and Conti tires? Conti tires don't do anything great but don't do anything horribly. Why 20" vs 19 or 18?

Not a criticism in the least just wondering about the the underlying facts influencing your decisions.
 

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I would never do it, but they do look very nice.
 

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I used 235 35 20 tires because they have a close circumference to the stock tires. With the 245s your speedo is going to be off by 8-10% (when your speedo says 65 you'll be doing 70+). But the car will stick to the road sooooo much better than the stock tires, as good as the ELR in my opinion.
 

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Discussion Starter · #13 ·
Thanks for all of the feedback. The first question that I've heard is "why do it". Customizing cars is 100% personal preference. I'm a 90's car customizer gone green. The wider stance with a lower amount flexible rubber also helps improve handling, especially when cornering.

When choosing wheels, the typical standard max wheel upsize is called a Plus 3. That means you would purchase a wheel that is 3 inches larger in diameter than the original factory size, as a typical max. Usually going higher than that will result in a tire size that is extremely thin because the primary objective is to ensure that the overall diameter of the new configuration is the same as the factory configuration.

Regarding the speedometer accuracy. This is purely a matter of circumference. The percentage difference in the circumference directly reflects the percentage difference in speedo accuracy. The circumference of the factory configuration measures 2099.5 mm while the configuration that I have chosen measures 2134.7 mm. This results in a 1.7% increase compared to factory specs. Therefore, my car will travel 1.7% faster than factory specs. When my speedo reads 60 MPH, I will actually be traveling 61 MPH. I can live with that. For speedo accuracy, an almost perfect configuration is 235/35-20 and the most accurate tire for the Volt running on 20s is 225/35-20. However, I wanted a little more width and a little more rubber around my wheels.

Thanks for all of the feedback.
 

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Thanks for all of the feedback. The first question that I've heard is "why do it". Customizing cars is 100% personal preference. I'm a 90's car customizer gone green. The wider stance with a lower amount flexible rubber also helps improve handling, especially when cornering.

When choosing wheels, the typical standard max wheel upsize is called a Plus 3. That means you would purchase a wheel that is 3 inches larger in diameter than the original factory size, as a typical max. Usually going higher than that will result in a tire size that is extremely thin because the primary objective is to ensure that the overall diameter of the new configuration is the same as the factory configuration.

Regarding the speedometer accuracy. This is purely a matter of circumference. The percentage difference in the circumference directly reflects the percentage difference in speedo accuracy. The circumference of the factory configuration measures 2099.5 mm while the configuration that I have chosen measures 2134.7 mm. This results in a 1.7% increase compared to factory specs. Therefore, my car will travel 1.7% faster than factory specs. When my speedo reads 60 MPH, I will actually be traveling 61 MPH. I can live with that. For speedo accuracy, an almost perfect configuration is 235/35-20 and the most accurate tire for the Volt running on 20s is 225/35-20. However, I wanted a little more width and a little more rubber around my wheels.

Thanks for all of the feedback.
I'm also a 70'80'90'20' mod guy gone green myself. :) Welcome to the club brother... Your understanding the physics of tire dimensions/weight/mpg/handling is key on and I couldn't have said it better myself. Looks good btw, i really like it...
 
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