Not interested in buying your tires but super interested to hear how the 18s work with ride, handling, and efficiency. Please post your results when you can!

 

Yeah for sure, will keep you updated.
So far the car feels noticibley faster and quicker to slow.
Lots more fun, as in lots more.
I have a bolt and a volt and after the wheels there is no comparison.
Im expecting around a 7-8% increase in efficency but I will let you know on that.
Ride is softer and the cornering is more floating until the tires dig in.
My tire choice, well kind of. Kumho Solus 4S HA32, 265-60-18
I think I made a poor choice (I rushed!), as the efficency is poor.
I was concerned, the wheels would not be avalable so I just went for this choice.
All in it was $2200 CAD with sensors etc.
About the same as a new set of 21s!!! tires, with fitment.
Plus the weight alone. I think around 17lbs per corner.
All I know is I can just carry the 18s but the 21s I roll.

 

I’m not sure about the logic here except some that live in the north prefer 18s in the winter.

The 21s on the Blazer are self sealing (for a nail or screw) the Kumho’s are not and unless you’re carrying a spare who cares about tire weight/changing a tire, if you have a flat you’re going to get towed.

I’m not sure why the car would seem faster considering the 18s and 21s are almost the exact same diameter/circumference and 68lbs difference in weight is negligible, ride is probably better.

As for the Kumho tires you right, probably a poor choice per the link below-----different size but probably about the same results for your size (note the rolling resistance)-----there goes your increased mileage. The Kumho tread pattern is a knock off of the Michelin Cross Climate with less tread depth.

Last, $2,200 CAN (about $1,600 US) for 4 wheels, 4 tires, 4 TPMS and mount and balance-------------couldn’t come close to that in the US.

Life is full of choices.

2020 Auto Bild All Season Tyre Test - Tyre Reviews And Ratings

2020 Auto Bild All Season Tyre Test

www.tyrereviews.com

 

Here they are

 

AI Overview



A 17-pound reduction in weight for each wheel and tire (unsprung weight) can make a noticeable difference in your vehicle's performance. This is because lighter wheels improve acceleration, braking, handling, and ride quality by reducing the rotational inertia and the load on the suspension. A general rule of thumb is that a pound of unsprung weight reduction is equivalent to shedding up to ten pounds of sprung weight (weight of the vehicle body).

Here's a more detailed look at the potential benefits:

• Improved Acceleration:
  Lighter wheels require less energy to accelerate, leading to quicker 0-60 mph times and improved overall acceleration.
  
  
• Enhanced Handling:
  Reduced rotational mass makes the car more responsive to steering inputs, resulting in crisper handling and a more nimble feel.
  
  
• Better Braking:
  Less weight to slow down means shorter braking distances and potentially reduced brake fade, especially during aggressive driving.
  
  
• Smoother Ride:
  The suspension can react more efficiently to road imperfections, leading to a more comfortable ride.
  
  
• Increased Fuel Economy:
  While the impact on fuel economy may be minimal, lighter wheels can contribute to slightly better gas mileage due to reduced rolling resistance.
  

Overall, the difference can be quite significant, especially when considering the combined effect of all four wheels. Some drivers might even perceive a more dramatic improvement than these quantifiable benefits would suggest, as the car may feel more eager to change direction and accelerate



Yes, I do need a spare tire or a repair kit. I will see if there is a space saver.

I find most people just prefer the aesthetics and that’s why 21s are used.

As you said, its all about choices, that's what makes the world more fun

I also have another set for the winter my commute is 250 km round trip and in -25 I need every advantage.

Bought the blazer because I got a crazy deal $51600 cad all in, on a 2024 RS in June 2025 always wanted one but they cost so much when released.

Brand new! It was made OCT 23. Must have been in the stop sale and got lost in the shuffle!

The dealer said it was dumped on them in May 2025. After all the updates its been good, but it did need many of them and a couple of visits.

I like the car but felt it was a little slow to give strong acceleration like the Bolt (2017), it felt more like the Volt (2017). It was good, but not wow, now it is at least for me.

I'll get a better set of tires next time, to be honest with my kms, most sets only last 2 years anyway, around 60,000km

For the winters I have Ipike's same size slightly different rims.

 

AI Overview



A 17-pound reduction in weight for each wheel and tire (unsprung weight) can make a noticeable difference in your vehicle's performance. This is because lighter wheels improve acceleration, braking, handling, and ride quality by reducing the rotational inertia and the load on the suspension. A general rule of thumb is that a pound of unsprung weight reduction is equivalent to shedding up to ten pounds of sprung weight (weight of the vehicle body).

Here's a more detailed look at the potential benefits:

• Improved Acceleration:
  Lighter wheels require less energy to accelerate, leading to quicker 0-60 mph times and improved overall acceleration.
  
  
• Enhanced Handling:
  Reduced rotational mass makes the car more responsive to steering inputs, resulting in crisper handling and a more nimble feel.
  
  
• Better Braking:
  Less weight to slow down means shorter braking distances and potentially reduced brake fade, especially during aggressive driving.
  
  
• Smoother Ride:
  The suspension can react more efficiently to road imperfections, leading to a more comfortable ride.
  
  
• Increased Fuel Economy:
  While the impact on fuel economy may be minimal, lighter wheels can contribute to slightly better gas mileage due to reduced rolling resistance.

Overall, the difference can be quite significant, especially when considering the combined effect of all four wheels. Some drivers might even perceive a more dramatic improvement than these quantifiable benefits would suggest, as the car may feel more eager to change direction and accelerate



Yes, I do need a spare tire or a repair kit. I will see if there is a space saver.

I find most people just prefer the aesthetics and that’s why 21s are used.

As you said, its all about choices, that's what makes the world more fun

I also have another set for the winter my commute is 250 km round trip and in -25 I need every advantage.

Bought the blazer because I got a crazy deal $51600 cad all in, on a 2024 RS in June 2025 always wanted one but they cost so much when released.

Brand new! It was made OCT 23. Must have been in the stop sale and got lost in the shuffle!

The dealer said it was dumped on them in May 2025. After all the updates its been good, but it did need many of them and a couple of visits.

I like the car but felt it was a little slow to give strong acceleration like the Bolt (2017), it felt more like the Volt (2017). It was good, but not wow, now it is at least for me.

I'll get a better set of tires next time, to be honest with my kms, most sets only last 2 years anyway, around 60,000km

For the winters I have Ipike's same size slightly different rims.

Be sure you take AI with you and not a 68lb kid-----------------you'll loose that tremendous weight advantage. If your decisions/logic is AI based it sure picked the wrong tire, the rolling resistance of your Kumho's is about as bad as it get's---------------AI should have told you that. You seem to have missed replying to how you managed to buy the complete package (wheels, tires, TPMS and mount/balance) for $2,200 CAN, $1,600 US will get me 4 decent wheels and just about EVERYTHING cost more in Canada (no offence to our Canadian friends/members it's just a fact).

 

you do realize 17x4 / 5400lbs is only 1.2% less weight. So it will make no noticeable differences in all the points that the AI-junk reasons gave you.

....but if you like the fact you can lift it the tire and is more fun for you to drive ...those are what matters...

I'll keep the AI-reasons in mind...next time i don't want to give a ride to somebody i don't like...."I can't take you because AI said that without you I'll have a smoother ride"

 

you do realize 17x4 / 5400lbs is only 1.2% less weight. So it will make no noticeable differences in all the points that the AI-junk reasons gave you.

....but if you like the fact you can lift it the tire and is more fun for you to drive ...those are what matters...

I'll keep the AI-reasons in mind...next time i don't want to give a ride to somebody i don't like...."I can't take you because AI said that without you I'll have a smoother ride"

For acceleration, the rotational wheel mass/inertia plays more than just the 1.2% total mass decrease since you're not spinning up/down as much wheel mass/inertia. Not sure about the AI rule of thumb of 10:1 between wheel rotational mass/inertia and sprung mass, but this general rule seems about right. In fact, the AI did pretty well.

 

I don’t normally bite but why not?

You have used the 1.2% as your assumption, but this is the total weight of the SUV.

Its clearly stated that this is unloaded weight (because tires and rims are not suspended above the suspension) not total weight.

Therefore you would need to know the unloaded weight of the components to get a real percentage.

The general rule of thumb is 3.5 to 10 times ratio, unloaded vs loaded.

So, 4.2% to 12% of the total weight of the SUV.

Now if I asked you to loose 4.2 to 12% of your body weight, my guess is you would notice.



I had no idea AI would have this reaction. For that I apologize.

 

I have no idea how 17 lbs reduction per wheel is 12% of load shedding.

Fact the blazer EV weighs around 5400lbs (its in the fact sheets) ...ok without rim or tires it is still above 5000lbs.

You should not have bothered to bite as i was not taunting...just pure physics. Unloaded weight of what ? ...the force required to extend or distend a spring is governed by Hooke's law. So the weight above the springs is more than 5000lbs...that dominates the reaction of the spring when you hit a pot hole etc..hence the quality of response of the shock absorbers is not going to be affected by the weight of the wheel

Also forgetting the springs...the energy needed to move a car is a function of the total weight and coefficient of drag and road friction.

Good luck with your unloaded argument remind me of this discussion of unladen swallow in Monty Python

Good luck with the trust in AI thing...I sure miss the Pythons...they would have made a sketch on it a la "confuse the cat".