|
Wheels | Tires | Spacers | Hub -- Sponsored by The Tire Rack Specific topics relating to wheels and tires. |
|
Thread Tools | Search this Thread |
05-23-2012, 02:23 PM | #1 |
$4,900 till FR-S
Join Date: May 2012
Drives: 1999 Mazda Protege
Location: Tennessee
Posts: 20
Thanks: 0
Thanked 4 Times in 2 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
|
What return from going with lighter wheels?
What return would I expect from going with a lighter wheel to replace the factory FR-S wheels?
I am considering Enkei RPF1's in a 17"x7.5" +38 offset. These wheels weigh 15.2 lbs. according to TireRack. That's approximately 5 lbs less than the factory wheels. What will this do for my car? How big of a change does reducing unsprung weight actually have on a car? |
05-23-2012, 04:50 PM | #2 |
Senior Member
Join Date: Dec 2011
Drives: 2011 Outlander XLS, 2013 FR-S Blue
Location: Calgary, Canada
Posts: 634
Thanks: 129
Thanked 168 Times in 102 Posts
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
|
Rule of thumb I've always heard is 4x the weight for unsprung. There's also maths for how far it's from the axle but meh.
So 5lbs a corner = 20lbs = same effect as removing 80lbs of body weight. |
The Following 2 Users Say Thank You to Khyron686 For This Useful Post: | civicdrivr (05-23-2012), TPO (05-23-2012) |
05-23-2012, 05:05 PM | #3 |
Senior Member
Join Date: Mar 2012
Drives: 2018 Golf R
Location: Richmond, VA
Posts: 2,807
Thanks: 5,386
Thanked 1,095 Times in 647 Posts
Mentioned: 68 Post(s)
Tagged: 7 Thread(s)
|
A pound saved in the wheel/tire is worth more then a pound saved elsewhere. Its rotating mass, you should notice a difference in acceleration, braking and steering.
__________________
Parting out HERE
|
05-23-2012, 05:07 PM | #4 | |
Senior Member
Join Date: Mar 2012
Drives: anyone seen my steering wheel?
Location: Double Shoals, NC
Posts: 121
Thanks: 3
Thanked 23 Times in 12 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
|
Quote:
If we use this calculator http://robrobinette.com/et.htm a 2750 lb car with 200 flywheel hp has a 1/4 mile et of 14.70 seconds If you reduce the weight of the car by say 40 lbs (5 lbs per corner = 20 lbs * 2 for our rule of thumb) to 2710 lbs then the 1/4 mile et is 14.63 seconds. It's about like having 3 extra horsepower, or approximatly 1.5% more on our fictious car. So for the lighter wheel you will see a bit quicker acceleration times, and a very slight increase in fuel mileage. There are also handling characteristics that will become more apparent as well. Firstly lets make a few assumtions lets say we have a 2750 lb car with equal corner weights so 687.5 lbs per corner and our unsprung weight is 50 lbs per corner. Then our sprung to unsprung weight ratio is 13.75:1 What this number ultimately means is how much the chassis is upset by bumps. The higher the number is the less bumps will affect the chassis. If we then reduce our unsprung weight to 45 lbs per corner our ratio becomes 15.278:1. This means that not only is a bump less likely to throw off the car from its line but that there is also effectively more force available to push the tire back to the pavement (it's not actually that way but its a simple way to explain it). Also because there is less weight the damping becomes more effective. That can be a plus or a minus depending on how effective the damping was for the given conditions prior to the weight change, though more than likely it will be a plus as I don't know of any car that is perfectly damped. |
|
The Following 10 Users Say Thank You to DEnd For This Useful Post: | 20valvewynn83 (08-08-2012), 86'd (05-23-2012), civicdrivr (05-23-2012), Guff (05-28-2012), kwood9000 (05-23-2012), Laika (05-24-2012), merlin2111 (05-23-2012), slaxx (05-24-2012), TPO (05-23-2012), YukiHachiRoku (05-24-2012) |
05-23-2012, 05:24 PM | #5 |
ლ(ಠ益ಠ)ლ
Join Date: Apr 2010
Drives: E36 5.7 V8
Location: Bronx, NYC
Posts: 1,573
Thanks: 194
Thanked 198 Times in 112 Posts
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
|
Basically, the engine has to work less to get the wheels up to speed. Therefore, you have better responsiveness in acceleration. The brakes also work less to bring the wheels to a stop. The OEM 86 wheels are very light; so I don't see the reason to shell out unless you go wider, which will help your lateral traction tremendously.
__________________
I wish I was cool enough to have an FR-S
|
05-23-2012, 05:27 PM | #6 | |
Member
Join Date: Nov 2011
Drives: Ultramarine FR-S
Location: Quebec
Posts: 86
Thanks: 5
Thanked 19 Times in 7 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
|
Quote:
|
|
05-23-2012, 05:57 PM | #7 |
Add lightness!
Join Date: Apr 2012
Drives: 17' WRX
Location: Boston
Posts: 1,253
Thanks: 380
Thanked 888 Times in 411 Posts
Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
|
Yeah 21 pounds for a 17x7 wheel is heavy. Not light at all. The lightest wheels in that size will be around 12-13 pounds which would be a substantial weight savings. I'm trying to see if I can find a set of Velox PG-5s around here...no luck so far. 12.5lbs for 17x7 though!
|
05-23-2012, 06:01 PM | #8 |
Because compromise ®
Join Date: Jan 2012
Drives: Red Herring
Location: australia
Posts: 7,735
Thanks: 3,999
Thanked 9,376 Times in 4,136 Posts
Mentioned: 60 Post(s)
Tagged: 0 Thread(s)
|
|
05-23-2012, 10:09 PM | #9 | |
ლ(ಠ益ಠ)ლ
Join Date: Apr 2010
Drives: E36 5.7 V8
Location: Bronx, NYC
Posts: 1,573
Thanks: 194
Thanked 198 Times in 112 Posts
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
|
Quote:
Motegi traklites are forged and the 17s weight 14 lbs. $250 a wheel.
__________________
I wish I was cool enough to have an FR-S
|
|
The Following User Says Thank You to blur For This Useful Post: | NYC BRZ (05-24-2012) |
05-24-2012, 05:10 AM | #10 |
$4,900 till FR-S
Join Date: May 2012
Drives: 1999 Mazda Protege
Location: Tennessee
Posts: 20
Thanks: 0
Thanked 4 Times in 2 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
|
Thank you to everyone for the info.
Thank you DEnd for the very informative answer. And thank you Captain Snooze for correcting my typo. That was way off. |
05-24-2012, 11:55 AM | #11 |
Senior Member
Join Date: May 2012
Drives: race cars
Location: Newport Beach, CA
Posts: 253
Thanks: 31
Thanked 150 Times in 68 Posts
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
|
one thing that is being ignored here is how unsprung weight will effect the suspension. Think of how much more your arm has to work when you lift a dumbbell that is 25% heavier. Same goes for the springs and dampers on your car. heavier wheels keep the suspension from reacting as fast as it would with less weight simply because of the inertial forces of the increased weight.
on a similar chassis, (miata) 5 lbs in wheel weight IS butt dyno noticeable in both centrifical force related ways (accel, decel) as well as compression and rebound related ones (comfort, lateral grip, etc) |
The Following 2 Users Say Thank You to Matt Andrews For This Useful Post: | civicdrivr (05-24-2012), Racecomp Engineering (05-24-2012) |
05-24-2012, 05:06 PM | #12 |
Senior Member
Join Date: May 2012
Drives: Silver AT Limited
Location: Seattle
Posts: 823
Thanks: 145
Thanked 344 Times in 159 Posts
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
|
So from what I read are only upsides, no downsides to going lighter?
|
05-24-2012, 05:13 PM | #13 |
Senior Member
Join Date: Mar 2012
Drives: Carless...
Location: SC
Posts: 174
Thanks: 129
Thanked 43 Times in 24 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
|
|
The Following User Says Thank You to Lost For This Useful Post: | civicdrivr (05-25-2012) |
05-24-2012, 05:26 PM | #14 |
Senior Member
Join Date: Dec 2011
Drives: 2013 BRZ
Location: Madison, WI
Posts: 308
Thanks: 67
Thanked 56 Times in 33 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
|
Lighter wheels make your wallet lighter.
|
The Following 6 Users Say Thank You to ubersoph For This Useful Post: | catsspat (02-19-2017), civicdrivr (05-25-2012), crash (05-25-2012), ft86Fan (05-31-2012), mechaghost (06-05-2012), MtnDrvr86 (05-24-2012) |
|
|
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Return of Datsun! | Mr.Jay | Other Vehicles & General Automotive Discussions | 65 | 03-28-2012 05:35 PM |
Tiger Woods Announces Return To Sex | Axel | Off-Topic Lounge [WARNING: NO POLITICS] | 4 | 02-25-2010 05:42 PM |
FT-86 the return of the Celica? | 1660 | Scion FR-S / Toyota 86 GT86 General Forum | 11 | 12-29-2009 10:58 AM |