Hey all! As you already may know I have 20's on my torch red. I think I may have them sold with the tires and I'm looking for something different. What I'm looking for are opinions on wheel size, and wheel selection, I am going with CHROME. If none of the wheels are do-able please advise on that too...

Wheel Size:

20x8.5 OR 18x9

Wheel Style:

WHEEL NUMBER 1:



WHEEL NUMBER 2:



WHEEL NUMBER 3:
THESE ARE BOYD CODDINGTONS IN POLISHED, I DON'T REALLY CARE FOR THE POLISHED WHEEL.



OR WHEEL NUMBER 4:



OR NONE OF THE ABOVE

I really respect EVERYONE'S opinions and tastes, that's why I like this forum so much! Honest but respectful criticism!!

 

Well if I had to pick from the above, I'd have to go with the last one....

For personal choice, check Crossroadz direct - 18 Bullits just hit TODAY - that's the way to go in my opinion.

(and 18 size wise anyway - to maintain your performance edge - heard about losing some with the 20s....)

 

Number 3. The Boyd Wheels.
Go for 18" or possibly 19, but never 20. Whithout even considering the performance issue, 20's or bigger just don't look right on a Mustang.

 

I like #2 and #3 for the Stang.

 

#2 in a 20 would be really nice

 

hmm? #3, then #2. i like them both. i've heard of 4+ month waits for the boyds though.

 

Torch,

I think those are all pretty good choices, and they are all definitely different styles. 20" rim is too big for me, but they are still cool. I think I like #1 then #4, then #3. I like having the deep dish lip on the rim personally better then the flat flush look on #2.

Good luck

Sam

 

Wheel number 4 it looks more like the 07 Shelby GT-500

 

I pick #3. And definately don't go bigger than 18" for appearance and performance reasons. I've copied and pasted my physics analysis of the effect on performance from going to a rim 2" larger in diameter (1" larger radius). It isn't exact because I made a few assupmtions to simplify the calculations and such, but I think it gives people a good idea of exactly what people mean when they say larger rims hurt your performance.

When you go to larger diameter rims, even if the rims weigh the same amount, you will be slower with the larger diameter rims because now the weight is concentrated farther from the center of rotation. This means that the larger diameter rims have a larger moment of inertia, which means it now requires more torque to provide the same rotational acceleration to them.

You can aproximate the moment of inertia for a rim be the formula I= 1/2*MR^2 where I is moment of inertia, M is mass, and R is the mass of the rim. As you can see, the R term is squared, which means if you increase the radius of the rim by a certain amount, the moment of inertia increases by that amount squared. In other words, going from a 16" to a 18 " rim, the radius goes from 8" to 9". Let's say that both rims weigh 24 lbs (for comparison's sake.) Lbs aren't really a unit of mass, but of gravitational force so we use 1 lb = 4.45 N to get that the force on these rims if acceleration due to gravity is 9.8 m/s^2 to be 106.8 N. We then use Newton's second law, F=ma and solve for m. m=F/a, so the mass of these rims is about 10.9 kg. Now, 1 m = 39. 4", so the radius of these rims is .203 m and .228 m respectively. Plugging these values into the equation of moment of inertia for the rim gives us I= .449 kg*m for the 16" rim and I = .569 kg*m for the 18" rim. That results in a 26.6 % increase in moment of inertia for the two rims. I could have arived at the same result by simply taking the difference in the squares of the two radii, deviding by the original radius, and multiplying by 100. In other words, % change in I = (RF-RI)/RI*100 where RF is final rim radius and RI is initial rim radius.Newton's second law for rotational motion is T=Ia, where T is torque, I is moment of inertia, and a is rotational acceleration. As you can see, the increase in rotational inertia results in a proportional decrease in acceleration for a given applied torque. In other words, your wheels would accelerate 26.6 % slower with rims 2" greater in diameter and equal weight.

The formula used is for the moment of inertia of a hollow cylinder about a central axis. It obviously is not compleely acurate for a rim because of the spokes and the fact that it is not perfectly cylindrical, but it provides a decent aproxamation and lets the point be seen. Even with equal weight rims, a small increase in diamter (only 2") can result in a large increase in moment of inertia, as well as a proportional decrease in rotational acceleration.

 

Okay Guys I had to make a decision rather abruptly last night as I sold my current wheels and tires. When I ordered them this morning everything I wanted or was leaning toward was out of stock at discount tire! Tire Rack didn't have anything I liked in 18's and I initially bought the 20's I just sold from Tire Rack.

I REALLY wanted chrome, and I didn't have the leadway in time as the buyer of my wheels wants them ASAP! I could have ordered but it would have been a couple of weeks.

I appreciate all the input you guys have given me. jsheehan, thanks for the information. I was trying to find an 18" to go with, I really didn't want bullitts as that is what I had on my 2002 and wanted to try something different don't get me wrong they are a good looking wheel, and once again NOTHING in stock. SOOOOOOoooooo here I am again running friggen 20's!! So I chose what they had in stock:

NUMBER 2! I guess I'm going to have to live with it for now and if they really look that stink I will put em up on ebay again and lose my hiney on $$$$! Honestly I was going to go for #3 or Number 4.

 

I like #2 the best, good choice. Yeah I would have done 18 or 19's top. But You got to do what you got to do. Good luck, show us some pics when there on.