Ok, I have a 2008 Accord coupe and plan on getting new rims soon. Thing is I'm not sure whether to go with 18s and lower no more than 1-1.5 inchs or go with 20s. The 18s will have more tire for comfy ride less likely to bend rim, but I will need to lower in order to get wheel gap out n look better. There is a rim available in 20s that's not available in the 18s. I probably will not lower with the 20s. Anyone have experience with this and what do you recommend? This car is my daily driver with a 100 mile+ commute plus speedbumps,etc. Thanks

 

Not only will twenty inch wheels negatively impact your ride, they will also negatively impact your braking, acceleration, fuel economy, and handling. If all you care about is the look, then the twenty inch wheels will probably suffice, but for all other metrics, the eighteens are a better all around wheel.

 

I agree with Shippo 200% . 18"s cost less and fit much better than 20" wheels..



WheelBrokerAng

 

I would say, 18's would be the perfect size of wheels to get unless you are just going to display your car. There are a lot of negative factors if you decide to get 20's one would be the cost and ride comfort.

 

Actually the 20s should give you better fuel economy since you're effectively gearing down your transmission, but they'll ride so terribly that you won't care. If you have the money, just bag it. If you're even considering 20s then you probably aren't THAT concerned about lateral Gs, and the ride is excellent... plus you can park hard as hell. I was rolling in a Buick with factory air ride for a while, the nasty streets of olympia feel like fresh blacktop.
edit: also you have the advantage of being able to air up over speedbumps, which is a luxury i would love to have.

 

I'm trying to understand your opening comment about 20" wheels giving better fuel economy. You do understand that unless you haven't compensated for the larger wheels by using tires with a shorter sidewall, the effective gearing will be unchanged regardless of which wheel size you use (within reason).

Long story short, due to the additional rotational mass of the 20" wheels, your fuel economy will be reduced.

 

Wait, what size are the factory wheels? I'm used to 18" being already 4 inches larger in diameter than stock.

 

But it can be said that generally a larger wheel/tire combination will yield a taller gearing. In a perfect world where the weight of the wheels weren't a factor, the taller gearing would yield a mild bump in fuel economy. Right?

 

You continue to miss the point, the outer diameter of the tires does not change when you bump the wheel size, consider the following:
2008 Honda Accord Coupe:

• With 17" wheels: Tires 225/50 R17 - Diameter 25.9"
• With 18" wheels: Tires 235/45 R18 - Diameter 26.2"
• With 20" wheels: Tires 245/30 R20 - Diameter 25.8"

Notice how the outer diameter is virtually identical?

As for the weight, once again, you're missing the point; even if the larger wheels were made of an exotic material and weighed less than the OEM wheels, they would still have a significantly higher rotational mass (also known as "angular kinetic energy"). How? Because the bulk of the weight (the rim) is pushed further away from the axis of rotation. Many studies have been done which show the maximum wheel size before the rotational mass starts becoming an issue is in the 16" to 17" range; anything larger is either to accomodate large brakes (not an issue on the 2008 Accord Coupe) or for bling.

Regardless, the 20" wheels will reduce fuel economy, handling, braking, and acceleration. You can either take my word for it, do some research on it (a good starting point is here: Rotational energy - Wikipedia, the free encyclopedia), or continue to believe something which isn't true.

 

18" ...but if you are inclined towards getting a 20" wheel, no reasoning is good enough to stop you.