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Tire size limit on Challenger and Charger- why so skinny?

Discussion in 'New Challenger, 300, Magnum, Charger' started by MRGTX, Mar 26, 2015.

  1. MRGTX

    MRGTX Well-Known Member

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    I have been shopping around Challenger Scat Packs and I was puzzled to see a 480hp car with 245s...I recall some facts about why the Challengers (and Chargers) ended up with narrow wheel wells but the facts are escaping me.

    Is this considered a major handicap for these cars? How big can you go in the aftermarket?
    IIRC, the Hellcats come with 275s at least, right?

    My relatively wimpy Mustang can easily accommodate 315s in the rear and 305s in the front (wth carefully selected offsets)...doesn't seem fair! FWIW, I run 285s on mine currently and still wish for more.
     
  2. tazdevil

    tazdevil Member

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    Partly because narrow means less rolling resistance and better fuel economy.
     
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  3. valiant67

    valiant67 ...

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    The wheelwells were pretty much determined before there was a performance version of the car as I understand it.
    It's been mentioned before and the cost to add more tire (through factory body modifications) would have been very large.
     
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  4. moparroy

    moparroy Active Member

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    Keep in mind force of friction is independent of surface area (laws of physics) - its only really a matter of rubber compound
     
  5. tazdevil

    tazdevil Member

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    Don't know where you found that law. You seem to say that any skinny tire will corner or roll same as a wide tire. NAHAH!
    The compound of the rubber has much to do with rolling resistance. Tire manufacturers can reduce rolling resistance with harder compound, but then performance in wet or snow is reduced dramatically.
     
  6. AHBGuru

    AHBGuru Active Member

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    The Pursuits got a 245/55/18 option in late 2014, for fleets that have a mix of Dodge and Ford (very common). Most of the Charger Pursuits have used the thinner 225/60/18 size since 2006, with Continental, Goodyear, and Firestone changing the compounds over the years to make the W-rated tires stick.

    I am currently using the 245/55/18's on my 2013 Charger, and it feels perfect. Ride is still very good.

    With the weight of the Hellcats, my concern would be load and speed rating, considering the amount of heat that could build up in the sidewalls of the cars going well in excess of even the fastest of regular SRT cars. Since the Chally Hellcat is more the straight line champ, it probably isn't as prominent of a concern than what one would (or should) have with the Charger. A little higher sidewall gives more cushion, and likely offers more of an expanded cooling surface. at 205-210 mph, nobody wants a blowout. Chrysler has long been a company that truly excelled at building a vehicle to handle very high speeds.
     
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  7. moparroy

    moparroy Active Member

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    Cornering is much more than just a matter of friction and skinnier tires tend to be a harder compound and thus a lower coefficient of friction = lower force as well. Racing slicks are wider so they can use a softer compound so the weight of the vehicle can be supported with lower pressure in a softer compound tire. All I am saying is don't be fooled that a wider tire in and of itself will improve your friction (thinking mainly for acceleration). The law is certainly true - I recall that from high school physics - but certainly again from first year engineering mechanics. According to Wiki its known as Amontons' Second Law but I don't recall if that is the name - too long ago.
     
  8. TheMan

    TheMan What color are the clouds in your world?
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    Correct. The force is one of shear between the "tooth" of the road surface and the tire compound matrix.
     
  9. Mike V.

    Mike V. Mopar-nac The Moderator

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    The wheel wells is not really the issue. The design of the rear suspension. The location of the rear sway bar inhibits larger tires from the factory.

    Will tires larger than 275 fit, yes it is possible.

    Mike
     
  10. valiant67

    valiant67 ...

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    Yep - everything has a cost. One of the costs of IRS is the limited tire room.
     
  11. ImperialCrown

    ImperialCrown Moderator
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    Did the visionaries foresee a Hellcat when these cars were developed ~15 years ago?
    They knew a V8 would be offered, so they made room for that.
    Viper was developed and designed as a supercar from the beginning.
    You can't just 'tub' a unibody LX without great expense, difficulty and compromise. Maybe it was easier to hack them up in the rear leaf spring/BOF days for straight line drag strip duty. It is just not practical for a well-mannered general daily driver like a Hellcat with a rear seat and trunk.
     

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