Wheel/Tire Dillema on my 69 Camaro

[Nutsy]

Please tell me what you would do. I have a 69 Camaro with DSE Tubs (not yet installed), and DSE Quadra link rear. I am fighting with myself about what rear rims/tires to run. Here is what i am looking at:

19x12 On the back with 345/30/19

Pros: Killer Looks, Killer stance, Rims that i want are available in 19x12
Cons: Michelin is the only people making a tire of that size, may require a bit more modification to clear properly

or...

18x12 on the back with 335/30/18

Pros: Plethora of tire choice
Cons: The rims i want aren't available in that size. Either would have to be modified or new rims chosen. Rims/Wheels may not fill the well the way i like and look too much like a donuts.

or...

Any idea's?

Trev

[JohnnyR]

19s look the best on a 67/78 due to the rounded wheel wells. Just check out Prodigy. On a 69, 18s look the best due to their squared-off wells. JMO

Personally, I like a little more sidewall on my tires. 18s for me.

-j

[Blake Foster]

You saw how the 335 look with the 20"s IMO the 19's just look better than 18's but that is a personal opinion, i can get you a really good deal on the tires and possibly the wheels as well, give me a call and i wil look into it for you. i would go for the wheels you want and suffer on the tire as the wheel is the most important part

[Nutsy]

Blake I will give you a call tomorrow.

Trev

[Steve1968LS2]

Originally Posted by JohnnyR

19s look the best on a 67/78 due to the rounded wheel wells. Just check out Prodigy. On a 69, 18s look the best due to their squared-off wells. JMO

Personally, I like a little more sidewall on my tires. 18s for me.

-j

Actually I think 18's look the best on a '67-68 if you have the stance right..

see:
http://www.z069.us/68/exterior/speedway.jpg

The main problem with 19's is the performance hit you take and the cost/limited availability of tires.

I say go with the 18's.. look great and gain performance.

[Nutsy]

Why is there a performance hit with 19s?

[BeCool68]

Thought I would chime in on this duscusion. I like the 18's on a 69 but like 17's on a 67 and 68 just wish the tire size was slight taller then the 315 35 17. 69's seems to have more wheel openning in the rear to handle 18's. Just my thoughts.

[Speedster]

nutsy -
The sidewall is so short on 19's. There is almost zero deflection (flex). The tire doesn't have as much chance to work as, well... a tire.

[Steve1968LS2]

Originally Posted by Nutsy

Why is there a performance hit with 19s?

It has to do with moment of inertia and it's not just that the 19" combo is heavier. It's that it's heavier farther away from the center of the wheel. As weight moves farther from the center it has a exponentially worse effect both on acceleration on and on stopping.

Think of a lever and the saying "give me a lever long enough and I will move the world"..

Here, for braniacs (unlike myself) this site should give headache.. lol
http://hyperphysics.phy-astr.gsu.edu/hbase/mi.html

For people more like myself..
http://en.wikipedia.org/wiki/Moment_of_inertia
&
http://www.britannica.com/eb/article-9042379

Ok, so they are talking about bike wheels.. same principal..
http://www.canecreek.com/168.html

So to sum it up:
Polar moment of inertia
The resistance of an object to rotational acceleration. When the mass of an object is distributed far from its axis of rotation, the object is said to have a high polar moment of inertia. When the mass distribution is close to the axis of rotation, it has a low polar moment of inertia

Wheel weight is bad.. wheel weight farther from the axis of rotation is worse. That why a 20-inch wheel that weights 30lbs is far worse in regards to acceleration and braking when compared to a 17" wheel.. even if they both weighed the same (which I doubt they would) since most of the weight of the 20" combo is so far from the center point of the wheel.

Did any of that make sense? lol

It's not that you shouldn't run 19's or 20's or whatever. It's just that you should know the physics behind what you decide to do and understand what trade offs some decisions entail.

[camaro2nv]

Nitto also makes a 345/30R19
Specs for ya
http://www.nittotire.com/#index%2Etire%2Einvo