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20" rims

Discussion in 'Off Topic Threads' started by tracyhunter, Nov 21, 2011.

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  1. tracyhunter

    tracyhunter Member

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    If you put 20" rims on a car w/15" rims would you get less/more/the same mpg?
     
  2. Neil Winston

    Neil Winston Well-Known Member

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    Way worse, on the order to 30% in fact. But it will be a shorter drive to the club and that will partially offset the reduced miles-per-gallon you will calculate.

    Neil
     
  3. grntitan

    grntitan Well-Known Member

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    If you go with the right tire profile, you can make the 20" wheel/tire combo the exact same overall diameter as when you had the 15" wheel/tire combo. It would mean having low profile tires. Then nothing will change. Am i correct Neil?
     
  4. Brian in Oregon

    Brian in Oregon Well-Known Member

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    You get more LPG.

    (Laughs Per Mile)
     
  5. Jeff P

    Jeff P Well-Known Member

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    and your speedometer would be way off, wouldn't it, since it's calculating by RPM, and if the tires were bigger, you'd be traveling farther in the same amount of time, hence, faster...

    And I'm confused about the MPG. If the outside diameter of the new tires were bigger, assuming (HUGE assumption) that it took no more gas to turn them, you'd go farther on the same amount of fuel. Obviously, this is not the case, because if it were, we'd all have 48" monster truck tires on....

    But I can't make my pointy little head come to the 30% less figure Neil tosses out....
     
  6. trapshootin hippie

    trapshootin hippie Well-Known Member

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    Put tall tires on the rear and little ones on the front for great gas mileage, Always going down hill that way.


    GneJ
     
  7. Russ-in-Pa

    Russ-in-Pa Well-Known Member

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    And you will look Ghetto Fabulous.
     
  8. 2@8lo

    2@8lo TS Member

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    Grntitan is correct you can have the same OD as the 15" it will just be a low profile tire
     
  9. TC

    TC TS Member

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    Grntitan and 2@8lo are correct however, the low profile tires will result in a ride like a wooden wheeled farm wagon. (Lack of sidewall cushioning).
     
  10. grntitan

    grntitan Well-Known Member

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    Russ,

    The 20" rims themselves do not look ghetto. Alot of pickup trucks now come factory with 20" rims and with the correct profile tires they look good. When you add the low profile tires i mentioned above is when it reaches the ghetto'd look.

    ...................................................................................................


    2@8lo,

    Thanks for the backup. I wasn't sure if my mind was think'n right or not.
     
  11. Ahab

    Ahab Well-Known Member

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    Do you want to look like this?




    ahab_2008_030396.jpg
     
  12. tracyhunter

    tracyhunter Member

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    Ahab, that is what I am trying to do.I wanted to raise the ground clearance of the differentials on my beater by just adding rims.the guy at the tire shop said it would use more gas. thats why the question about the mpg.I thought it would take less.so much for what I know.
     
  13. Bruce Specht

    Bruce Specht Well-Known Member

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    From my prespective that would truly be a waste of money. If your thinking of "upgrading " conside the "plus 2 concept and look at 17" wheel and tire packages. far less in cash and less risk of damage from pot holes
     
  14. Remstar311

    Remstar311 Member

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    To get more clearance you really need to make that up in the tires. Bigger rims can get bigger tires, but you can get pretty good size 15's too.

    That will eat gas like you wont believe, brakes probably be under powered too. If your going big tires you will likely get a mud terrain type traction which is a gas hog too.

    Then your speedo is going to be off.

    Along with Grntitan and others,
    you can go up in tires and keep the same original OD. Like Bruce said go up 2. Then you should still have adequate sidewall and braking. There are all sorts of conversion calculators online for this math.

    Good Luck

    Nick
     
  15. grntitan

    grntitan Well-Known Member

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    Nick has it right. Simply make your tire profile greater. It will in turn give you more ground clearance. It will however change your speedo and will need to be recalibrated it if bugs you. The amount of speedo error will depend on how much you change the OD. I did this with my pickup. It has 18" rims and i simply changed the tire profile size and went from 32.5" to almost 35" OD with just a subtle change. That may not sound like alot but it is quite noticable in ground clearance. I also added Bilstein 5100 series shocks that allowed me a few more inches without changing the steering angles and such. Anytime you make any changes, make sure to have an alignmenet done.

    Matt
     
  16. grntitan

    grntitan Well-Known Member

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    Unless you made a drastic change(like adding really large wheel/tire combo), i doubt it will affect the ABS in any way. I certainly haven't noticed any changes on my truck and it has ABS and traction control. The computer shouldn't be affected in any way. It should automatically adjust for any fuel air requirements the engine senses like it does in every day use.

    Keep in mind when you add larger wheel and tires thus increasing weight, the overall braking/stopping distance could be affected. Heavier wheel/tire combos will put more strain on the brake calipers, discs and pads. I upgraded my brakes before making the changes. I just went with EBC discs and pads and added SS braided brake lines as well as a High Temp Dot 4 brake fluid. Of course with these upgrades, my truck actually stops much better than before. Thats a whole different subject though.
     
  17. Stl Flyn

    Stl Flyn Well-Known Member

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    By adding a larger circumference you change the power ratio. Just like gearing. Thus you use more gas to get to, and holding speed. You do however slow the tire rotation ratio, or lower the amount of rotation to travel the same miles, in essence, saving mileage to the tire. Huh? I know. I am trying to figure out what I just said. Jon

    I would think it would affect stopping the same way. It would take more force on the pads to stop. You would need larger brake rotors to equal out the ratio. Jon
     
  18. W.P.T.

    W.P.T. TS Member

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    wpt_2008_0303_1331.jpg

    wpt_2008_0303_1332.jpg

    wpt_2008_0303_1334.jpg


    These are 20" rims and there isn't anything Ghetto about them on this car, they are actually part of a Performance package from the factory ...
    WPT ... (YAC) ...
     
  19. Tron

    Tron Supporting Vendor Supporting Vendor

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    It will kill your gas milage, it's tough on wheel bearings, wreaks havoc on electronics such as abs and suspension parts and it looks really stupid to boot. It MAY even void your warranty.
     
  20. TOOLMAKER 251

    TOOLMAKER 251 Active Member

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    If the vehicle is within 7-8 years old the speedo can be re-calculated for tire height. One of the con's of 20" tires is the cost, my factory wheels are 20" and tire replacement is $350 each.
     
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