Anybody Notice?
Page 1 of 2 12 LastLast
Results 1 to 15 of 23

This is a discussion on Anybody Notice? within the Engine Performance forums, part of the Tutorials & DIY category; I'll be getting a new set of rims and tires before this winter and I was woundering if anybody noticed ...

  1. #1
    Registered User WRXgotit's Avatar
    Join Date
    Feb 2006
    Location
    Lakewood, WA
    Posts
    666

    Anybody Notice?

    I'll be getting a new set of rims and tires before this winter and I was woundering if anybody noticed a diffrence in Torqe/HP when getting 17in-18in. Some have talked about this so I'm just woundering how many this has happened too .
    .......... two cents below _______________
    02 WRX/ owner since I could dream.
    WFC The 3rd III cobbcobbcobbcobbcobbcobb
    (((((((((((((((( NOW STAGE2 ))))))))))))))))
    _______________________________.

  2. Remove Advertisements
    ClubWRX.net
    Advertisements
     

  3. #2
    Registered User psb02wrx's Avatar
    Join Date
    Nov 2005
    Location
    Long Island, NY
    Posts
    300
    Quote Originally Posted by WRXgotit
    I'll be getting a new set of rims and tires before this winter and I was woundering if anybody noticed a diffrence in Torqe/HP when getting 17in-18in. Some have talked about this so I'm just woundering how many this has happened too .

    i had 18s on my car for a few months. coming from the stock 16s, the only thing i noticed was the ride quality. with the wider, lower profile tires, the ride was a little harsher - or if you look at it the other way, there was more "road feel" with the larger wheels. as for hp / torque - i didn't notice much of a difference, if any. although i hadn't had my car that long when i put the wheels on there. i can't see it being that dramatic a difference.
    rumble young man, rumble...

    Quote Originally Posted by Maccgyver
    ...Sounds like we got a vh-1 storyteller here...

  4. #3
    Registered User
    Join Date
    May 2005
    Location
    PA/NJ
    Posts
    71
    You don't actually lose horsepower or torque from moving to a larger wheel. However, this is perceived by some people because, generally, the bigger the wheel the heavier. This increases unsprung weight, which makes every aspect of performance worse. This includes slowing acceleration, which makes for the perceived notion that larger wheels somehow take away horsepower.

  5. #4
    Moderator Integra96's Avatar
    Join Date
    Apr 2002
    Location
    Utah
    Posts
    16,989
    I Support ClubWRX
    Quote Originally Posted by sisforsurfing
    You don't actually lose horsepower or torque from moving to a larger wheel. However, this is perceived by some people because, generally, the bigger the wheel the heavier. This increases unsprung weight, which makes every aspect of performance worse. This includes slowing acceleration, which makes for the perceived notion that larger wheels somehow take away horsepower.
    Incorrect. Heavier/larger wheels decrease horsepower.
    "Did you sleep well?"
    "No, I made a couple of mistakes."
    -- Steven Wright

  6. #5
    Registered User psychobooe's Avatar
    Join Date
    Mar 2004
    Location
    USAF
    Posts
    17
    Quote Originally Posted by sisforsurfing
    You don't actually lose horsepower or torque from moving to a larger wheel. However, this is perceived by some people because, generally, the bigger the wheel the heavier. This increases unsprung weight, which makes every aspect of performance worse. This includes slowing acceleration, which makes for the perceived notion that larger wheels somehow take away horsepower.
    I think he means that you don't necessarily lose horsepower when you get bigger wheels. If the 17/18in wheels and tires that you put on weigh the same as the 16in combo that you take off, then there will be no difference in unsprung weight and therefore no lose of power.
    Try not, do or do not. There is no try. - Yoda
    Mods

  7. #6
    Moderator Integra96's Avatar
    Join Date
    Apr 2002
    Location
    Utah
    Posts
    16,989
    I Support ClubWRX
    Quote Originally Posted by psychobooe
    I think he means that you don't necessarily lose horsepower when you get bigger wheels. If the 17/18in wheels and tires that you put on weigh the same as the 16in combo that you take off, then there will be no difference in unsprung weight and therefore no lose of power.
    It's not only how much unsprung weight, it's where the unsprung weight is. 18" wheels that weigh the same as 16" wheels will most definitely slow you down - unless the weight is concentrated near the hub.

    http://www.physics.uoguelph.ca/tutor...ro.angacc.html

    "Did you sleep well?"
    "No, I made a couple of mistakes."
    -- Steven Wright

  8. #7
    Registered User
    Join Date
    May 2005
    Location
    PA/NJ
    Posts
    71
    Quote Originally Posted by Integra96
    It's not only how much unsprung weight, it's where the unsprung weight is. 18" wheels that weigh the same as 16" wheels will most definitely slow you down - unless the weight is concentrated near the hub.

    http://www.physics.uoguelph.ca/tutor...ro.angacc.html

    Understood, which is why I said heavier wheels decrease performance in both acceleration and deceleration.

    Quote Originally Posted by Integra96
    Incorrect. Heavier/larger wheels decrease horsepower.
    Please post some sort of evidence or at least a theory to prove your statement... given and I will glady edit my post as I don't like spreading misinformation
    I would love to know how your wheel size and weight affects your engine making horsepower.

  9. #8
    Moderator Integra96's Avatar
    Join Date
    Apr 2002
    Location
    Utah
    Posts
    16,989
    I Support ClubWRX
    Quote Originally Posted by sisforsurfing


    Please post some sort of evidence or at least a theory to prove your statement... given and I will glady edit my post as I don't like spreading misinformation
    I would love to know how your wheel size and weight affects your engine making horsepower.
    Google: Newton + physics. There's a mountain of evidence for his theories.

    Less power is "produced" by the wheels when they are heavier. The engine, of course, is the power source, but the wheels are the agent - i.e., the wheels perform the work on the road/dyno or vice versa. Just do a simple thought experiment. Dyno a car with 16" alloy wheels. Now dyno a car with 1600" wheels made of lead. Intuitively, what difference would you expect in the measured power?
    "Did you sleep well?"
    "No, I made a couple of mistakes."
    -- Steven Wright

  10. #9
    Registered User ynotajb's Avatar
    Join Date
    Sep 2004
    Location
    mmmm,, tater salad
    Posts
    2,711
    Quote Originally Posted by Integra96
    Google: Newton + physics. There's a mountain of evidence for his theories.

    Less power is "produced" by the wheels when they are heavier. The engine, of course, is the power source, but the wheels are the agent - i.e., the wheels perform the work on the road/dyno or vice versa. Just do a simple thought experiment. Dyno a car with 16" alloy wheels. Now dyno a car with 1600" wheels made of lead. Intuitively, what difference would you expect in the measured power?
    +Juan million

    exactly the way to think about it

  11. #10
    Registered User
    Join Date
    May 2005
    Location
    PA/NJ
    Posts
    71
    The question was do bigger wheels take away horsepower, and I said no, they don't. Because they don't, because the engine still is making the same power. I also clearly said that bigger wheels decrease acceleration just like they decrease braking performance... perhaps the OP meant wheel horsepower, in which case I wouldn't have responded because I have no hands-on experience or knowledge about wheels causing parasitic loss, especially when it's +1 or 2 pounds per wheel.

    Maybe I should've just posted "yeah, you'll notice slight differences in performance in general" and called it quits. Regardless, just a little misunderstanding I think

  12. #11
    Registered User Micah's Avatar
    Join Date
    Oct 2005
    Location
    Ocean Grove, NJ
    Posts
    4,142
    Sometimes I plan on buying lightweight 16" or possibly 17" wheels. Stocker weighs 16.5lbs each (at least this is what I seem to be finding using google).

    BBS RG-F - 16x7 - 1 pc forged - offset +48 - 12.3lbs - $412 each
    Kosei K-1 TS - 17x7 - gravity cast/shot peened - offset +50 - 13.7lbs - $199 each

    I'd rather stay with the stock rims for now.
    Torch Red 2002 Chevrolet Corvette Z06 46k mi.
    Black 2002 Subaru Impreza WRX 6-speed 94k mi. my mod list
    10/08/2006 - 14.089@103.01 (5-speed with well worn clutch, no launch)
    "Six stars gleaming, five speeds breaking, four tires chirping, three differentials working, two liters screaming, one turbo boosting... it's what makes a Subaru all-wheel-drive, all we'll drive."
    for Bugeye owners my BOV thread Service Manuals

  13. #12
    Administrator RayfieldsWRX's Avatar
    Join Date
    Oct 2002
    Location
    The Old Folks Home
    Posts
    46,880
    I Support ClubWRX
    It was pretty clear what the OP was asking. No one really thinks that somehow the larger wheels are going to lower the hp output of the engine.

    But yeah, put on some heavy wheels, and you will suffer the detriments associated with unsprung weight and rotational inertia.
    --Ray
    Grandfather of the Bugeye Mafia
    2013 Subaru BRZ Limited
    2002 Subaru WRX Bugeyebrid Wagon

  14. #13
    Moderator YBNormal07's Avatar
    Join Date
    Jul 2003
    Location
    PA
    Posts
    6,244
    I Support ClubWRX
    Larger wheels = typically heavier = < AWHP

    Larger wheels do not equal < HP.

    Taller wheels = lower gear ration = < AWT

    Taller wheels do not equal < TQ.

    Plain and simple.

    The advent of dyno's measuring HP at the wheels seriously complicated everyone's lives!!

    Crap CAI + BOV = < HP.
    tEh PriUs=teH faSTah!@@!
    08 Audi S5 Black Diamond edition
    SOLD: 05 SWP Legacy GT Limited 5MT, 13.3ish@105 (stage 2) crappy stock clutch
    SOLD: 04 MPS/SW WRX Sti. 12.971 @ 103.97 (stock)
    278 AWHP/283 AWT, Catback exhaust
    306 AWHP/341 AWT, Stage 2
    (Scott) Moderator-STi, Drag Racing, Car Purchasing, and Tutorial Forums

  15. #14
    Registered User
    Join Date
    Dec 2006
    Location
    St Paul, MN
    Posts
    3

    what a crazy ass thread

    I feel like pretending to contribute today (since I can't figure out what I will do about a catch can for oil)

    Anyhow - as far as I can deduce from the Torque for Dummies example above... both Mass and Radius affect EFFECTIVE torque. Furthermore, the impact of Radius is actually squared making it even more of an impact. Now, measuring Torque is quite complicated and usually is not actually performed. Instead it is a derivative of the Horsepower output calculated using the RPMs (or some ****). So - in my opinion - radius is much more important than mass and I agree with whoever said it won't change the Engines torque - but I don't think anyone really cares about that - it does, however, change the effective Torque of "the system" thereby making the vehicle potentially quicker/slower in different situations... flame on!!

  16. #15
    Administrator RayfieldsWRX's Avatar
    Join Date
    Oct 2002
    Location
    The Old Folks Home
    Posts
    46,880
    I Support ClubWRX
    :shrug:
    <crickets chirping>
    --Ray
    Grandfather of the Bugeye Mafia
    2013 Subaru BRZ Limited
    2002 Subaru WRX Bugeyebrid Wagon

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •