Make a car slower? My 2nd gen 185/65-60/15 make it slower then the 1st gen 185/65/14?

 

if the wheel and tire combo weigh more yes... or if they are a bigger diameter they could... but seen as those tire setups are pretty close to the same outside diameter your pretty much riding on if the 2nd gen combo weighs more then the 1st gen combo...

 

205/50-15s are nice on the 1st gen!

When you start to get upwards of the 16" and up rims, then they will hurt acceleration some.

 

the farther you move centrifigul (spell check? LOL) mass away from the center of axis point, the more it weighs. This means: a larger diameter wheel will weigh more once it's rolling.

Goodyear did an experiment on the benefits of forged (light weight) wheels. They dynoed a duramax. Then added 1 lb of wheel weights to each rear wheel and dynoed it again. The truck lost almost 20 whp due to the added weight on the wheels. On a 15" wheel, 1/2 an ounce weighs over a pound at 65 mph. That's 32x it's actuall weight. Just imagine how much an extra 5 lbs per wheel weighs at 100 MPH trap speed!!!!

 

Your wheels don't move in a reciprocating motion..it's called centrifugal motion.

 

AH HAH, that's the word I needed. THNX

 

yes typically a larger wheel will weigh more once spinning... but you also have to figure in the weight of the tire... now seen as the outside diameter of the whole wheel and tire combo is pretty much exactly the same... pretty much to get an acurate idea if this will effect your performance much your going to have to weigh each combo and see if either weighs more then the other... most likely the 15" rim combo will weigh a bit more but it may not depending on the brand tires and the type of tires... which a lot of people don't relize can make just a big a difference as the rim size does... i've seen tires the exact same size (205/60R15) weigh about 4lbs difference and that was just between two different brands that i've personally seen... there could be bigger differences between other brands of the same size.. yet another reason you should never mix brands of tires..

 

If you have a 14" tire and rim combo that weighs the same as a 17" tire and rim combo, the 17" combination will hurt acceleration more than the 14" combo. Weight isn't the only hinderance!

 

yeah but he is asking about two sizes that are very close in size 185/60 15 and 185/65 14... he was asking about those two wheel combo sizes.... and it still depends on the diameter of the tire... obviously with 17s your going to have to run an extremely low profile tire which is gonna be a ton heavier then the stock 14 inch tire... i was pointing out that in this example that the rim wasn't the biggest factor... and i have to beg to differ my buddy used to have a ford probe... had a fair amount of mods and we went for a heavy as 15" rim (stock) to a ultralight 17"rim and tire package lost over 6lbs to each wheel and gained over 2 tenths in the 1/4 and gained 2mpg in everyday driving.... so you can't say that a lighter 17" rim will hurt acceration as long as the outside diameter of the rim and tire package is the same or very close the only time the bigger rim package that is lighter is gonna hurt performance is if the overall outside diameter of the whole rim and tire combo is larger...

 

Well with everything in life there are exceptions. But in your example, your friend went from a heavy rim to a lighter and larger rim. But I wonder how much he could have gained if he went to a lighter 15" rim?!?!

Good discussion though. Thats what the boards are intended to do.