Larger rear tires?

Discussion in 'Challenger Wheels, Tires and Brakes Forum' started by Hopslayer, Oct 24, 2018.

  1. Hopslayer

    Hopslayer Full Access Member

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    Saw a guy on Youtube made a video about what his top 5 mods for the Challenger would be. He said he didn't like the gap between the fender and the rear tire, so he recommended putting 275's back there and keeping the 245's on the front. Anyone do this? What are the pros and cons? I assume he's just adding the taller tire on the same rims, correct? There is a good gap there, but I'm not sure if I would gain much by doing it. Thanks.

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  2. 70-426_10-SRT

    70-426_10-SRT Full Access Member

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  3. IntimidatorRT

    IntimidatorRT Moderator Staff Member

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    well you could always lower with with some eibach springs and shocks. should do for about 2 in drop
     
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  4. 70-426_10-SRT

    70-426_10-SRT Full Access Member

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    Agree, that would improve the looks and handling
    but then you have the Speed Bump Scrapes, parking curb hits to the spoiler, and steep exits out of some parking lots.
    Did that on my Stealth & Stratus RT :(
     
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  5. Diehard

    Diehard Full Access Member

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    I would strongly suggest that the first thing you do is get familiar with tire size designations and what they do when changed.

    For example, the 275's you mention is the width of the tire, not the diameter or height.

    Typically you want to maintain the same (or close to the same) tire diameter when making tire width or height(diameter) changes.

    If you're wanting to reduce the space to the fender without changing tire diameter very much....
    1. Remember when you change the tire diameter, only half of that change impacts the space, since it's actually the radius that counts. for example...increasing tire diameter by 1" adds 1/2" to top(reducing space to fender) and 1/2" to the bottom(raising the entire car).

    2. By lowering the car with its suspension.

    3. You can increase the tires profile. For example: assuming your tires are 245/45/20 or 275/40/20. Both of which have about a 28.7" diameter. Changing the 275's to say 275/45/20 would make the diameter about 29.7". 1/2" off the gap but 1/2" higher car, slight error on speedometer and a slight reduction in torque due to the larger diameter rear tires.

    In 70-426_10-SRT's case I believe it calculates to about a 1/8"+ increase in profile width. If he wanted to go much more, without changing his tire diameter very much he'd have to go with a smaller wheel diameter.
     
    Last edited: Oct 26, 2018
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  6. Diehard

    Diehard Full Access Member

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    Putting 275's on in place of the 245's would not change your tire to fender space. You would have to change your tire sidewall height which can reduce your tire diameter. However, if you stay reasonably close to your stock diameter, enough so as not to affect speedometer much, it would make very little difference.

    Sounds like you saw the video I just saw about the 5 modes, but the guy I saw did go to 275's in the rear but not to change the space. He said he was going with air cushions, so he could adjust his height.

    Here's the one I saw.

     
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  7. Hopslayer

    Hopslayer Full Access Member

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    What does he mean by 10 inch wheels and 8.5 inch wheels?
     
  8. 70-426_10-SRT

    70-426_10-SRT Full Access Member

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    Width of rim
     
  9. Chops

    Chops Member

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    What's up, Hopslayer! Interesting & unique rear quarter decals on your car. I definitely like the color combo. Have you done your tire upgrade, or are you still doing research & deciding? I'm going to do a similar tire upgrade. I have now, & am going to have mounted & balanced next week 2 Atturo AZ850 275/40/20 tires on my rear wheels. I would also like to put the same size on the front wheels, but I'm not sure yet if I can do that. Might have to do a 255 or 265 on the front. Good luck with everything!
     
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  10. SRT-Tom

    SRT-Tom Full Access Member

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    I replaced the 245/45-20 Goodyear RSA tires on my 2009 SRT with a staggered set of the new Cooper Zeon RS3-G1 ties. I stayed with the 245/45-20 (28.7 inches) size on the front and a wider 275/40-20 (28.7 inches) on the rear (Note- The 275 is the widest tire that you should put on a 9 inch wide wheel. (A 275 requires a 9-11 inch wheel.) Anything wider than a 275 will not wear or perform properly and could be dangerous- see attached diagram- image #2).

    The tire-to-fender gap space doesn't bother me. To shorten the gap, unless you lower the car, you will have to go with a bigger ratio tire, like a 275/50-20 (30.8 inches) or a 275/60-20 (33 inches). There are several problems going this route. First, the larger diameter tires are only suited for crossovers and SUVs and will adversely affect your handling. Secondly, they will not comply with the necessary speed rating that you need for an SRT. Thirdly, they will throw off your speedometer. And, finally, you may lose some torque.



    View attachment 2572 View attachment 2573 tire fitment.jpg
     
    Last edited: Dec 8, 2018
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