Size Matters. R15, R16 and R17 - Mazda 6 Forums : Mazda 6 / Mazda Atenza Forum

SCORPION6 · 05-11-2008, 12:22 AM

Long time ago I put this thread in mazda6tech

To read, is better if you use a magnifier

Business · 05-11-2008, 12:43 AM

*hugs his fd3s wheels*

SCORPION6 · 05-11-2008, 11:04 AM

Ok, I saw that Crossbow also added to this forum.
Here with a better size of letters

http://www.wam.umd.edu/~greghess/sizematters.pdf

http://forum.mazda6club.com/index.php?showtopic=29223

DennisW · 05-11-2008, 12:24 PM

There are other concerns regarding wheel size, one of the most important being brake size. A lot of bigger, heavier road racing cars simply need bigger brake systems than can be fit inside a 15" or in some cases, even a 16" wheel.

But, a very informative article, and an eye-opener for those who think those 18" or 19" rims are gonna give them a better handling car.

Awong124 · 05-11-2008, 05:56 PM

I think they did say that the 17's handled the best, it was just slowest due to more rotational inertia.

KevinK2 · 05-12-2008, 08:35 PM

counterpoint:

I once switched from a 60 series to a 50 series r-compond tire, same width, on a 924 turbo. I was amazed how much harder it pulled on the track in my usual 3rd and 4th gears, and lap times went down as gears used were the same, but I had lower gearing due to tire size.

The above test would have been better if tires were shaved to same diameter.

The 15" tire diameter was smaller than the 16", and the 17" was largest in dia. For a given torque at the axle, the tractive force will be higher based on 1/R, where R is the tire Radius. The lap time is related to the sq-rt of the general acceleration. Notice that the variation in lap times was 1.8%, and the variation in tire radius was 1.7%. The 2 lb weight difference, per wheel, is less than a .2% change in the car's weight, considering all 4 wheels.

If I correct the 16" and 17" times based on tire theoretical radius (sq-rt of radius ratio), the old and new total corrected times would be:

105.19 sec, 105.19 sec, 15" 11.535"
105.27 sec, 104.83 sec, 16" 11.632"
107.10 sec, 106.22 sec, 17" 11.728"

The 16" is the lap time winner, for that test.

The point is that if you are going to compare the wheel size, you need to keep the tire dia exactly the same. If that were the case, I'd expect the 16" to finish 1st, rather than a close second place.

05-11-2008, 12:22 AM	#1 (permalink)
SCORPION6 Mazda Guru Join Date: Apr 2003 Location: ACTUALLY IN USA. MIAMI FLORIDA UNTIL December 3, 2009. Panamá (Central America). Posts: 2,497 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	Long time ago I put this thread in mazda6tech To read, is better if you use a magnifier __________________ Mazda 6 (2.0) Automatic. Strato Blue Rx8 Rims 16x7,5 Offset:+50mm with Toyo Proxes 4 225/50 96V (40,2 lbs). 2.3 Draxas Header. 2.3 AEM SRI. Mobil 1 10W-30. Eibach Pro Kit. Bosch DOT4 Brake Oil. Kashima Brake Pads Britax Boulevard Baby Car seat. Pulstar Pulse Plugs

05-11-2008, 12:43 AM	#2 (permalink)
Business Mazda Guru Join Date: Apr 2005 Location: Draper, UT Posts: 7,013 Thanks: 1 Thanked 1 Time in 1 Post Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	hugs his fd3s wheels __________________ Now rocking a 91 Miata

05-11-2008, 11:04 AM	#3 (permalink)
SCORPION6 Mazda Guru Join Date: Apr 2003 Location: ACTUALLY IN USA. MIAMI FLORIDA UNTIL December 3, 2009. Panamá (Central America). Posts: 2,497 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	Ok, I saw that Crossbow also added to this forum. Here with a better size of letters http://www.wam.umd.edu/~greghess/sizematters.pdf http://forum.mazda6club.com/index.php?showtopic=29223 __________________ Mazda 6 (2.0) Automatic. Strato Blue Rx8 Rims 16x7,5 Offset:+50mm with Toyo Proxes 4 225/50 96V (40,2 lbs). 2.3 Draxas Header. 2.3 AEM SRI. Mobil 1 10W-30. Eibach Pro Kit. Bosch DOT4 Brake Oil. Kashima Brake Pads Britax Boulevard Baby Car seat. Pulstar Pulse Plugs

05-11-2008, 12:24 PM	#4 (permalink)
DennisW Mazda Guru Join Date: Aug 2006 Location: NW Indiana Posts: 2,616 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	There are other concerns regarding wheel size, one of the most important being brake size. A lot of bigger, heavier road racing cars simply need bigger brake systems than can be fit inside a 15" or in some cases, even a 16" wheel. But, a very informative article, and an eye-opener for those who think those 18" or 19" rims are gonna give them a better handling car. __________________ [b]"There are three easy ways of losing money - racing is the quickest, women the most pleasant, and the Stock Market the most certain."</span>

05-11-2008, 05:56 PM	#5 (permalink)
Awong124 Mazda Guru Join Date: Jun 2006 Location: Vancouver, B.C., Canada Posts: 2,759 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	I think they did say that the 17's handled the best, it was just slowest due to more rotational inertia. __________________ 2002 Honda Accord Coupe EX V6 AT My Cardomain 2006 Mazda 6 Sport GT-V6 MT My Cardomain, My Garage

Remove Advertisements Sponsored Links
Mazda 6 Club Advertisement

05-12-2008, 08:35 PM	#6 (permalink)
KevinK2 Mazda Guru Join Date: Jan 2005 Location: Delaware Posts: 2,239 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	counterpoint: I once switched from a 60 series to a 50 series r-compond tire, same width, on a 924 turbo. I was amazed how much harder it pulled on the track in my usual 3rd and 4th gears, and lap times went down as gears used were the same, but I had lower gearing due to tire size. The above test would have been better if tires were shaved to same diameter. The 15" tire diameter was smaller than the 16", and the 17" was largest in dia. For a given torque at the axle, the tractive force will be higher based on 1/R, where R is the tire Radius. The lap time is related to the sq-rt of the general acceleration. Notice that the variation in lap times was 1.8%, and the variation in tire radius was 1.7%. The 2 lb weight difference, per wheel, is less than a .2% change in the car's weight, considering all 4 wheels. If I correct the 16" and 17" times based on tire theoretical radius (sq-rt of radius ratio), the old and new total corrected times would be: 105.19 sec, 105.19 sec, 15" 11.535" 105.27 sec, 104.83 sec, 16" 11.632" 107.10 sec, 106.22 sec, 17" 11.728" The 16" is the lap time winner, for that test. The point is that if you are going to compare the wheel size, you need to keep the tire dia exactly the same. If that were the case, I'd expect the 16" to finish 1st, rather than a close second place. __________________ 04 6S atx hatch 93 RX-7, 75 Trident