17" magnums

[drewcrane]

less than the stock 15's.  i beg to differ the 17x8 or 17 x6, is the same diameter, if you study the difference between a 15 inch wheel , and a 17 ,the 17,s have more mass, there fore weigh more, check it with a scale, cause a 17 inch wheel will weigh more that a 15, the fact that you have 2 sets that weigh 5 lbs from each other, is negligable,i have a set of 15, and when i get time i will show you, i have seen a 20 lb diggerence depending on what wheel you have, all im saying is if you think that you are going to lighten up the car by simply changing from a 15, to a 17 inch wheel think again its the opposite!

[72bluNblu]

Drew-

Simply because the 17" rim is larger in diameter does not mean it has more mass, or weight. A 70's era wheel of any size, constructed with 70's technology, is likely to have more metal in it that a modern 17" wheel. Computer drafting and stress strain analysis, as well as CNC machining and improved casting techniques allows many modern wheels to use less metal for the same strength as their predecessors. Also consider that aluminum has a lower density than steel, and therefore a lower weight for the amount of metal used (2/3 lighter!). Since stock wheels were, and are still, not really constructed for weight reduction, a performance aluminum wheel is almost always several pounds lighter than a stock wheel (even comparing modern stock wheels to modern performance wheels). I wouldn't say that all 17's are lighter than stock or 70's era 15's, since the larger diameter may lead to more mass, but I'd be willing to bet (a lot) that there are quite a few performance bred modern 17" rims that are lighter than 70's era 15's. If you still don't believe me, get a weight on a stock 15" wheel. I'd bet its more than 15.6 lbs per rim, which was how much the last set of 17x8" rims that I had weighed. Believe me, if I had a stock 15" rim, I'd weigh it myself.

Now tires are a whole different matter, and vary quite a bit from brand to brand, but if you consider the same height/width of tire on a 15" rim to a 17", I'd bet you can still shave weight with a stock 15x8 to a 17x8 even considering the weight of the tire.

[drewcrane]

ok its real simple i have a set of 15 inch wheels,if you take a string and go around the diameter of both wheels, you will need 2 inches more material!period ,like i said you need to get a scale and weigh it your self since you haven done that, what you are doing is assuming,that makes an ass out of you and me , go get the wheel and see for your self instead of speculating about modern tech, and cnc machining, it does not make up for the physics of more mass,due to the larger wheel diameter,and more rubber too!i realize the weights vary quite a bit , however if you can find a17 in wheel to be lighter than a 15 inch wheel simply prove it!

[72bluNblu]

Ok, here's the deal. If I had the weight of a 15" stock wheel, I'd prove it. In the meantime, how about I first show that 16" wheel can weigh more than a 17"? Here you go.

ATX Chamber 16x8", 5 on 114.3 (same as 4.5"), ~4.5" backspace, weighs a whopping 27 lbs. Here's the link

http://www.wheelrack.com/wheels/WheelCloseUpServlet?target=runWheelSearch&showRear=no&filterSize=&filterFinish=&filterSpecial=&initialPartNumber=39856865TB&autoMake=Dodge&autoModel=D150+Pick-up&autoYear=1977&autoModClar=

American Racing Torq Thrust II 17x7", 5 on 4.5", weighs 19.0 lbs.



Here's the link
http://www.wheelrack.com/wheels/WheelCloseUpServlet?target=runWheelSearch&showRear=no&filterSize=&filterFinish=&filterSpecial=&initialPartNumber=5057765P&autoMake=Dodge&autoModel=Charger&autoYear=1973&autoModClar=340%2F440+OE+Engine

If you look closely, you'll see both of these rims are even made by American Racing. And, both of these rims will fit a 'Cuda or Challenger. They are both modern rims, made with modern techniques. This would be easier for me, but not all rim manufacturers  post the weights of their rims. At any rate, the 16" wheel has a smaller diameter, which was your argument, and still weighs 8 lbs more.

Now if I "cheat" I'll show you a 17" rim that is lighter than a 15" by a long shot.

Motegi Track Tracklite 17x7", 5x100mm, 5.62 backspacing, weight 14.0 lbs


Here's the link
http://www.wheelrack.com/wheels/WheelCloseUpServlet?target=runWheelSearch&showRear=no&filterSize=&filterFinish=&filterSpecial=&initialPartNumber=23887780FB&autoMake=Dodge&autoModel=Neon+SRT4&autoYear=2004&autoModClar=

And here's your old school, 15x7" American Racing Torq thrust. It weighs 18.4 lbs. Also notice, this is only .6 lbs lighter than the torq thrust II above.


and here's the link
http://www.wheelrack.com/wheels/WheelCloseUpServlet?target=runWheelSearch&showRear=no&filterSize=&filterFinish=&filterSpecial=&initialPartNumber=1055765AML&autoMake=Dodge&autoModel=Charger&autoYear=1973&autoModClar=340%2F440+OE+Engine

Of course its "cheating" because you can't put a motegi tracklite on your e-body, but I think it demonstrates my point. A 17" rim can be lighter than a 15" rim. In fact, the whole wheel is likely much lighter, since the rim is lighter and larger, which means that a 17" wheel has less tire than a 15" wheel. Since the rim is already lighter, you save even more by having less tire (if its the same height and width as the tire on the 15" rim). I'm sure there are racing rims that will fit on a 'cuda or challenger that are in the 15 lb range, I just didn't feel like scouring the 'net for them.

The physics of this is simple. Just because the rim has a larger diameter does not mean it has to have more material. It may be thinner, or have a more open design than another,smaller diameter rim. It may also be made out of a lighter material. If I could find a set of titanium rims in 17" this would be even more obvious. A less dense material can make up for the added material for the diameter, if in fact there is more material.

Good enough?

[Bullitt-]

Took our bathroom scales to the garage to gather a few facts...
  14" OE Road Wheel......               19.5lbs    maybe add a pound for center cap & trim ring   20.5
  215/70/r14 Radial T/A.                25.0lbs              add a pound for tread worn off (shot)     26.0
                                 total         44.5lbs                                               est. total        46.5

 17" OE '05 Mustang Bullitt rims w/
 235/55zr17 Pirelli PZERO
                                       total    49.5lbs

  255/45zr17 G-Force T/A                28.5lbs
  add the torque thrusts above         19.0lbs
                                           total 47.5lbs
 
consider an extra pound or two for 15" steels & larger tires & I think the weight difference is negligible.


               Now let there  be peace in the valley.....or at least on this board.

Da Bullitt

[72bluNblu]

So a 14" (x6?) OE road wheel (rim) is heavier than a 17x8" Torq thrust II rim by a 1/2 pound. Works for me. 

[71chally416]

Think I'll keep my Centerlines 

[360 'CUDA]

 

Think I'll keep my Centerlines 

 

[72bluNblu]

Think I'll keep my Centerlines 

Nothing wrong with that! 

[71chally416]

I'm glad I got them when I did. The price has went WAY up the last few years.
 

[72bluNblu]

Thats for sure. Looks like about $180 bucks from Summit now. I like the Torq thrust look myself, just love those 5 spokes with the gunmetal spoke finish.

[71chally416]

I almost got the spoked ones but I'm lazy about cleaning things and didn't want the hassle. 

[drewcrane]

like i said a 15 inch wheel weighs less than a 17, that is all I said, i didnt make any quotes about 16 inch wheels,i have wheels from 15,s to 22,s, if you think 1 to 6 lbs is not that much, go road race your car, if you can, cause i have and i do and when you want to go fast around corners ANYweight advantage is good, so like i said a 15 inch wheel is STILL lighter than a 17, no if, ands ,or buts, about it!if you read what i said you will see that is MY only argument,and i have proved it to my self and some else did too!do a little research instead of speculating,cause you are assuming! :bigsmile:peace!

[Bullitt-]

I thought the discussion was that 17" alloy wheels would be heavier than 15" OE steels....which apparently is not the case.     Not having road race experience does limit my perspective but it seems to me the added width, and associated traction gained, of the 255s over the 215s would more than offset the overall weight difference.

[72bluNblu]

like i said a 15 inch wheel weighs less than a 17, that is all I said, i didnt make any quotes about 16 inch wheels,i have wheels from 15,s to 22,s, if you think 1 to 6 lbs is not that much, go road race your car, if you can, cause i have and i do and when you want to go fast around corners ANYweight advantage is good, so like i said a 15 inch wheel is STILL lighter than a 17, no if, ands ,or buts, about it!if you read what i said you will see that is MY only argument,and i have proved it to my self and some else did too!do a little research instead of speculating,cause you are assuming! :bigsmile:peace!

Did I miss something? A 14" road wheel is heavier than a 17" Torq Thrust II. I'm pretty sure that would mean a 15" road wheel (if there was one) would be significantly heavier than a 17" inch Torq thrust II. Which was my entire argument. Alloy rims can be lighter than OE steel rims, even in 17" form. The fact that a 215/70/14 tire is lighter than a 255/45/17 was never my argument, and if you put a 255/70/14 on a 14"  rim, it would weigh more than a 17" with a 255/45/17. I thought I made it very clear above that you would have to compare like size tires as well, and that the rim would be the part that was lighter. Regardless, I don't know anyone that would race using a set of 14x5.5" rims with a 215/70/14. Or even a 15x6" rim with a 215/60/15, unless your race bracket required OE wheels, in which case you couldn't run 17's anyway.

and finally, you can look at this example.

This is a 17x7" Enkei RPF 1 for a Mustang. It has a 5x114.3mm bolt circle (4.5"), with a backspacing of 5.74". It will fit an E-body with a spacer or a spring relocation. It weighs 14.6 lbs.

http://www.wheelrack.com/wheels/WheelCloseUpServlet?target=runWheelSearch&showRear=no&filterSize=&filterFinish=&filterSpecial=&initialPartNumber=3797706545BS&autoMake=Ford&autoModel=Mustang+GT&autoYear=2008&autoModClar=Coupe


Now, with the above figure of 28.5 lbs for a 255/45/17 G-force TA, that gives you 43.1 lbs. That is lighter than the 44.5 lbs quoted for the 14" road wheel with a 215/70/14. Which shows that a 17" wheel can be lighter than a 14" wheel, even if you throw in a huge difference in the width of the rim and the width of the tire.

Drew, you've obviously misunderstood my point. My only point was that a 17" rim can be lighter than a 15" rim, which I showed already. Now with the tire info, I also showed that the wheel (with tire) can be lighter too. I have more than enough of an idea of how big a difference a few pounds of unsprung weight can make, since I have been involved with racing with previous vehicles. Hopefully you never saw this as an argument with you, since that wasn't my intention. I just wanted to point out the facts, which I think I have done.