problem with my 18's
#11
03-07-2006 | 05:33 PM
Senior Member
Joined: Nov 2005
Posts: 2,612
RE: problem with my 18's
If you properly plus size the wheel/tire combination, there is no change in diameter or circumference.
i.e. a 225/40R18 is the same overall diameter/circumference at a 225/45R17.....There is a 0.48% difference between the 2 sizes.
You can use this tire calculator to figure out what size tire you need to maintain your current wheel/tire size
http://www.discounttire.com/dtcs/infoTireMath.dos
i.e. a 225/40R18 is the same overall diameter/circumference at a 225/45R17.....There is a 0.48% difference between the 2 sizes.
You can use this tire calculator to figure out what size tire you need to maintain your current wheel/tire size
http://www.discounttire.com/dtcs/infoTireMath.dos
#12
03-07-2006 | 09:35 PM
Joined: Feb 2006
Posts: 279
From:
RE: problem with my 18's
Mazda guy, if that was the case, all out performsnce, you'd be running around on 16's, or even some 15's with the right offset. but that just looks dumb, so most don't go that route outside of the track.
i feel that if you want to roll on 20's more power to you, if you wanna run 15's that's all great. just find a wheel you like and go with it. but either way it will effect your ride and performance. I have a fairly heavy street set (2 sets actually) at about 21-23lbs each (just wheels) and a track set at 15lbs each...that's how i like it.
i feel that if you want to roll on 20's more power to you, if you wanna run 15's that's all great. just find a wheel you like and go with it. but either way it will effect your ride and performance. I have a fairly heavy street set (2 sets actually) at about 21-23lbs each (just wheels) and a track set at 15lbs each...that's how i like it.
#13
03-08-2006 | 05:20 AM
Joined: Nov 2005
Posts: 369
From: Montreal , Canada
RE: problem with my 18's
ORIGINAL: sstlaure
The larger diameter the wheel the heavier it is. (For the most part...some ultra expensive large dia wheels are also fairly light.)
1 lb of rotating mass is the equivalent of 7-10 lbs of dead mass on a vehicle.
Braking distances/wear are also increased with larger diameter wheels due to the increased weight.
You're right, you don't lose power, you just accelerate slower.
Now if the 18" wheels you are looking at are the same weight as the 17" wheels that came stock, then there would be no performance decrease.
The larger diameter the wheel the heavier it is. (For the most part...some ultra expensive large dia wheels are also fairly light.)
1 lb of rotating mass is the equivalent of 7-10 lbs of dead mass on a vehicle.
Braking distances/wear are also increased with larger diameter wheels due to the increased weight.
You're right, you don't lose power, you just accelerate slower.
Now if the 18" wheels you are looking at are the same weight as the 17" wheels that came stock, then there would be no performance decrease.
also , slower to start (torque) , but will be easier on HP once you get rolling ... just think of those big wheels on a bike compared to small ones as you're pedaling
as mentioned , it's the radius/diameter that counts in the end
#14
03-08-2006 | 10:56 AM
Senior Member
Joined: Nov 2005
Posts: 2,612
RE: problem with my 18's
ORIGINAL: 6Pack
you (might) add weight with a bigger mag .... but with a lower profile tire isn't it less heavy ?
also , slower to start (torque) , but will be easier on HP once you get rolling ... just think of those big wheels on a bike compared to small ones as you're pedaling
as mentioned , it's the radius/diameter that counts in the end
ORIGINAL: sstlaure
The larger diameter the wheel the heavier it is. (For the most part...some ultra expensive large dia wheels are also fairly light.)
1 lb of rotating mass is the equivalent of 7-10 lbs of dead mass on a vehicle.
Braking distances/wear are also increased with larger diameter wheels due to the increased weight.
You're right, you don't lose power, you just accelerate slower.
Now if the 18" wheels you are looking at are the same weight as the 17" wheels that came stock, then there would be no performance decrease.
The larger diameter the wheel the heavier it is. (For the most part...some ultra expensive large dia wheels are also fairly light.)
1 lb of rotating mass is the equivalent of 7-10 lbs of dead mass on a vehicle.
Braking distances/wear are also increased with larger diameter wheels due to the increased weight.
You're right, you don't lose power, you just accelerate slower.
Now if the 18" wheels you are looking at are the same weight as the 17" wheels that came stock, then there would be no performance decrease.
also , slower to start (torque) , but will be easier on HP once you get rolling ... just think of those big wheels on a bike compared to small ones as you're pedaling
as mentioned , it's the radius/diameter that counts in the end
#16
03-09-2006 | 02:01 AM
Joined: Mar 2006
Posts: 8
From:
RE: problem with my 18's
I put 17's on my 6 and i can hear it scraping on the back tires too. Mostly when i have people in the back seat. So i can imagine it doin the same with the 18's that you put on. Everyones talking about rolling the fenders, can someone tell me where you would have that done???
#18
03-09-2006 | 09:46 AM
Senior Member
Joined: Nov 2005
Posts: 2,612
RE: problem with my 18's
Check with a local body shop (not a dealership) about having the fenders rolled.
6 Pack, I believe you're right about the baseball bat. (I've heard of it being done that way.) Basically you are pulling the fenders out a little on each side creating a slight flare and rolling the lips from the sheetmetal away from the tires.
Again, if you're not sure how to do it, check with a body shop.
18's can fit fine if you have them set up just right (correct width/backspacing). I think the 18's are the best looking size, but 17's may be the best performing all-around.
I run the RX8 wheels on my wife's Mazda6 wagon (18x8 w/225/45r18 tires) and I'm sure that under the right circumstances (heavy load, etc.) that they would rub. Although we never heard them rub while they were on over last summer for ~12,000 miles worth of driving.
6 Pack, I believe you're right about the baseball bat. (I've heard of it being done that way.) Basically you are pulling the fenders out a little on each side creating a slight flare and rolling the lips from the sheetmetal away from the tires.
Again, if you're not sure how to do it, check with a body shop.
18's can fit fine if you have them set up just right (correct width/backspacing). I think the 18's are the best looking size, but 17's may be the best performing all-around.
I run the RX8 wheels on my wife's Mazda6 wagon (18x8 w/225/45r18 tires) and I'm sure that under the right circumstances (heavy load, etc.) that they would rub. Although we never heard them rub while they were on over last summer for ~12,000 miles worth of driving.
#19
03-09-2006 | 10:51 AM
Senior Member
Joined: Aug 2005
Posts: 1,802
From: Pittsburgh, PA
RE: problem with my 18's
hmm... i have never had any problems in my mazda6 with tire scraping. I've had a crew of 5 people in my car driving kinda like an *** to show of my car a bit and taking turns that were fairly sharp without powersliding and have yet to scrape. only problem i have had is the damn potholes. Had my one wheel dinged up and I know alot of people don't notice that, but I know it is there so that bothers me. The baseball bat method has definitely been used. My buddy did that trick to his truck to slap on bigger tires (he doesn't like spending money on fancy equipment that he will rarely use).
#20
03-09-2006 | 03:02 PM
Joined: Nov 2005
Posts: 369
From: Montreal , Canada
RE: problem with my 18's
The 18's won't rub , I suppose ... like sstlaure mentions ; 'cause they are 18 x 8 ..... usually a true 18 inch 'aftermarket' wheel will be at least 9in. wide for 18's ..... offset and backspacing and width play a decising role in the equation .