Wider tires.

Discussion in 'Dodge Challenger SRT Hellcat Forum' started by Bubbasan, Jan 19, 2018.

  1. Bubbasan

    Bubbasan New Member

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    Ok so I just melted my brains trying to find out what tire sizes and wheels sizes would work. Freaking off set and Inset, I’m so lost I could vomit pea soup.

    Read that 305 will work somewhere. But same size rim? Width? Oh man. Any one want to toss me a life line here?
     
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  2. 245pacer

    245pacer Active Member Site Supporter Level 4 MOTM Winner!

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    As you have probably heard tires from different manufacturers will fit a little differently so with that in mind I run 295/35/20 on my standard 9.5 wheels on the back . They are Michelin super sports and apparently are equivalent to a 305 of other manufacturers, when I put them on they just touched the inner plastic on one side of the car and sit probably inline with the top of the wheel arch . That should give you an idea of what tire you can fit , people have absolutely gone wider but I think you would have to massage the inner guard ( not difficult) . You can run an 11 inch wheel in the back if the tire you pick needs it .
     
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  3. 245pacer

    245pacer Active Member Site Supporter Level 4 MOTM Winner!

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    The car has the 295 s on . The pic is the 295 Michelin / 275 Perelli / 275 Michelin ( winter tire ) IMG_2371.PNG RenderedContent-8190D6B1-4525-45C4-BF7E-C52726452061.JPG RenderedContent-BD103446-D950-4F4B-8548-C14BA3219C16.JPG
     
  4. Bubbasan

    Bubbasan New Member

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    Great info. Thanks
     
  5. Diehard

    Diehard Member

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    First off I'm assuming we're just talking about the rear tires as the fronts could pose a problem.

    As you have read, many have been going from the 275/40R20's, which came standard on the SRT Hellcat and SRT 392, to the 305/35R20. The reason for the "35" instead of the "40"(tires aspect ratio) is to closely match the diameter of the original OEM tires. That's would make the 305's about 1% smaller in diameter which is well within the recommended limits.
    Although some have mounted 305 tires on a 9.5" wheel, the recommended range of wheel width for a 305 tire is typically 10" to 12", with 10.5" apparently being the most common used by most folks.

    Keeping in mind that the 305's are 30mm(approx. 1-3/16") wider then the 275's, that would result in each side of the tire sticking out 1/2 that amount on each side, approx. 15mm (19/32")

    Your stock wheels have an 18.5mm offset, which means the vertical centerline of the tires are 18.5mm(almost 3/4") inboard from the mounting hub of the wheel.

    Now the 2 considerations for selecting an offset are...
    1) To allow enough inboard clearance so as not to rub the inner wheel well liner.
    2) Not to push the tire beyond the the fender or to keep it at a minimum.

    I believe if you used an offset of 18.5mm there would be clearance on the inboard side(based on other peoples experiences as well as mine) but it may stick out beyond the fender a bit. I believe for this reason many of the after market wheels for this purpose are made with 24mm or 25 mm offsets. I've seen some at 27mm.They are actually allowing the tire to come closer to the inner wheel well wall so as not to have it stick out too far.
    (The larger the offset the more it moves inboard.)
    As you may find, if you search for other peoples experiences, some have said they fit fine with no rubbing and some have said they removed a little of that plastic material from the inner wheel well wall to insure no rubbing.

    I had mounted a borrowed set of M/T ET street S/S, 305/35R20 drag radials on my SRT 392, and which I believe had 10.5" wheels with 24mm offset. I could still slip my hand between the back side of the tire and the wheel well liner.

    Not to confuse you more but a tire width isn't exactly what is stated by that first number. For example, 305's are supposedly 305mm wide or 305 divided by 25.4 = 12". Some run a bit wider and some could be narrower.
    ALSO, industry standards say that if a tire is mounted on a wheel one size wider or narrower than it's measured wheel size it will gain or lose 0.2" in width. So this stuff could make a difference when it's close.

    Some have mounted 315's ith no problems or just the need for some minor plastic removal from wheel liner.
     
    Last edited: Jan 19, 2018
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  6. Db2016sp

    Db2016sp Member

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    A75A7966-2FA1-4560-90C8-2721151F169A.jpeg A lot of people have mounted the Nitto NT555R 305/35/R20 on the stock rims. The pros are they can be used on the stock 9-1/2” rims. The cons are they are a typical drag radial with limitations in wet and cold weather, and of course a lower top speed rating. If you never go over 155 mph then no worries.
     
  7. Bubbasan

    Bubbasan New Member

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    Is it worth or possible to increase the front tires as well?
     
  8. FastMikeR1

    FastMikeR1 Active Member MOTM Winner!

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    I would say yes, you can probably run 275 all four corners. I am running 315 on 11'' wheels in the back,i had to massage the inner fender to eliminate the rub. easy fix and well worth it.
     
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  9. Bubbasan

    Bubbasan New Member

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    I am running 275s on all fours atm. Did I miss something?
     
  10. FastMikeR1

    FastMikeR1 Active Member MOTM Winner!

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    sorry, i misread your post, you can probably got to 285 in front, but on a 9'' wheel i think it would bulge. I ran 285 on 10'' in the front on my 2010 SRT8. I had the staggered wheels at the time.
     
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  11. Bubbasan

    Bubbasan New Member

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    Ok. Thanks
     
  12. ArchGE

    ArchGE Active Member

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    I'm on 285/35's all around with our 9.5" wheels. I had 285/40's for a while but are hard to find with limited production. That is the widest tire "approved" to fit on a 9.5" wheel so is fine on the front, then what you care to experiment with on the back is up to you.
     
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  13. Bubbasan

    Bubbasan New Member

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    Thanks
     
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  14. SFCR

    SFCR Active Member Military Public Safety

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    Are you looking for more traction?
     
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  15. Diehard

    Diehard Member

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    Not sure if you updated your car since your first post but I never noticed that you have a Hellcat which means you already have 275's all around.

    The 305/40/20 will definitely work on the rear, however, the recommended rim width range for that tire is 10" to 12".(Some have mounted it on the 9.5" none-the-less. The 10.5" rims seems to be most popular size used. Although the tire manufacturers base their advertised tire width on the tire being mounted on an 11" wide rim.
    Also, most people using 305's seem to be using a wheel with a 24 or 25mm offset.
    If you were to put 305's on your existing rims, which have an 18.5mm offset, they would probably stick out a little bit beyond the fender.

    EDIT: Ooops! Just noticed that I had already responded to this question.
     
    Last edited: Feb 4, 2018
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  16. Bubbasan

    Bubbasan New Member

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    Any one running Nitto nt555 g2 tires? They seem like a good tire at a fair price. What pressure are you having them filled to?
     

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