Rep Power: 0

i just purchased some used tires and wheels. they are 17 inch velox wheels with a six point star design. *pic of wheels is in profile pic*. anyways i knew the tires weren't in the greatest condition but they weren't bad. i do get a vibration when i get over 50 mph. one other thing i noticed is that i barely got over 310 miles before i hit empty on fuel. would the tires and or wheels effect this? thanks and reply back

 
Rep Power: 813

big wheels will lower gas mileage. it takes more effort to turn them from a stop and also more to keep them turning due to the added weight. unevenly worn tires may also cause vibration, or you might just need to get them balanced.

 
Rep Power: 284

hub centric rings. warped rotors. or if there multi holed you prob have them in the wrong holes even though they fit.

 
Rep Power: 354

if you did NOT get any vibration going 50+ with ur old wheels/rims
then there are two BIG possible things:


1. hub centric rings
2. ur rims/tires isnt ballanced very well


also, bigger rims are heavier. hence it will make ur engine work harder for 1 rotation.....and therefore burning more fuel.

also bigger rims puts more weight on the ends of the wheel/tire which makes it more difficult to spin, which goes back to my first point

 
Rep Power: 813

not sure why everyone jumps to the rings. our cars are lug centric and its the lugs that center the wheel if you think about it, there is no purpose for the rings. one of mine fell off and i didnt even notice.

 
Rep Power: 267

i agree with gearbox with my old 17's i took out the hubcentric rings to see if it made a difference... and it didnt so i just left them off. never had a problem for over a year without them. i would check if there balanced first cause that with effect mileage along with causing shakes at highway speeds.

 
Rep Power: 0

i did have them balanced before i put them on. going back to the gas mileage issue, how much would i lose going from a 14in steelie to a 17in racing style wheel. the tires are 205 40 zr 17. can i get a fatter tire instead of using a low profile tire?

 
Rep Power: 813

your odometer might also not be reading properly with the wheels.

 
Rep Power: 0

yeah, i agree too, thats good things

 
Rep Power: 284

how about possibly a slightly bent wheel? wouldnt notice from the eye but would deff feel it.

 
Rep Power: 0

Hey I just got a pair of used rims (rota grid 17"). The tires are used too but were in good condition (falken 512s, 215 45 17). I had the same problem as you I had to get them balanced 3 times cause the first shop couldn't seem to get it right the first time. Make sure the tires are in good condition and don't give up. Regarding the gas mileage I am getting a bit less, but it’s not the end of the world. I was getting around 550km per tank now I’ll get somewhere around 520km. Oh make sure your aligned properly that will slightly help with wear, ride comfort, noise, and fuel mileage.

 
Rep Power: 813

yeah i went to three shops before sears finally balanced them once and now theres almost no vibration.

 
Rep Power: 0

i'm gonna try new tires when i get paid. do i have to get low profile tires when i do get new ones? on there now are 205 40 zr17.i live on the kansas side of kansas city metro but i find myself on the missouri side where the roads are pretty bad. i don't want to blow a tire or bend wheel. i would like to get a tire not low profile but smaller than stock

 
Rep Power: 239

heres an easy way to check milage if u got rims...

u need to know the overall diameter of ur stock tires (lets call this d) and new tires (D)

Both can be found here by entering the tire sizes: http://www.miata.net/garage/tirecalc.html

now...
1) start measuring ur miles on the odometer right when u fill up ur tank to the very top

2) once ur gas tank reads approx empty, fill up to the top again and note the number of gallons that u just filled up (G)

now ur odometer says the number of miles driven (m), thinking its on ur stock tires... to find the actual number of miles on ur new tires (M),

M/(pi*D)=m/(pi*d)
M=m*(D/d)

so now, to find actual average milage (lets call this Q cuz i feelz like it)...

Q = M/G = (m/G)*(D/d)



sooo for example... lets say my stock tires where 195-60-15, and new ones 215-45-17....

from the website, d=24.2 in D=24.6 in

my odometer reads 350 miles since my last fill up....and i just filled up 10 gal up to the top in my tank.... then my average milage

Q= (350/10)*(24.6/24.2) = ~35.57 mpg

this is an approximation, so theres gonna be an error...personally i would say +/- 2 mpg...

its convenient being a physicist/mathematician.......

 
Rep Power: 0

This equation is all good for a quick dirty guess; but the equation only takes into account the relationship of the overall diameters. You should account for the differences in coefficient of friction, new mass, width of tire etc... All these factors can increase or decrease you economy. Best way to see mpg is a simple comparison between new wheels and old ones. Run a couple months with old ones then switch to new ones and try you best to reproduce driving conditions, and then compare and you’ll have a decent answer

Those are my 2cents. But then again I’m no physicist or mathematician just an engineer.

 
Rep Power: 813

almost everyone i know with aftermarket rims has some vibration. and no problem using the stock rim. i think its due to the aftermarket being a generic design where the oem one is more balanced with the hub assembly.

 
Rep Power: 239

you're completely right... heavier rims, and added wieght do affect milage... but, if u think about it, everything is already taken into account from the measurment, not the equation.

for example...

lets say u had stock tires and got 400 miles out of one tank... and say u put heavier rims of the same diameter on ur car....you would automatically get less than 400 miles out of the same amount of fuel. you may get, sayy 350 miles... this difference in the number of miles u get out of one tank already reflects the added wieght and everything.... everything is contained in the measurment.

 
Rep Power: 239

some poeple say they do not have any vibration...leads me to believe that there are prob some wheels that are more "compatable" than others or maybe some wheels that are better construction than others....

who has no vibration with rims? and what rims/tires do you have?