Tire and rim width range safety

Discussion in 'SRT Hellcat Wheels and Tires' started by Tire God, Apr 6, 2016.

  1. Tire God

    Tire God Hellcat Member

    Joined:
    Apr 5, 2016
    Messages:
    153
    Likes Received:
    30
    Trophy Points:
    18
    Vehicle:
    Challenger SRT Hellcat
    The TRA(tire and rim association) got together with the NHTSA, RMA, DOT, and every other government organization that has to do with safety as well as the tire manufacturers. When the tire manufacturer says that their tire in a certain size fits a rim width range from 10"-12.5" or whatever it is, that info is to be followed 100% and is part of tire basics training. The concerning part for me, is that there are still shops willing to install wrong applications and not care (usually small performance shops or mom and pop shops). They take full legal liability by doing this.
    Here is the reason you shouldn't want what are called "misapplications" on your 70 thousand dollar sports car. When you stretch a tire on a rim, like the youtube video of a 225 going on a 12.5" rim, while entertaining to watch, it scares me that it will be put on a car and driven on. Same goes for squeezing a very wide tire on a narrow rim. The sidewalls of tires support the weight of the vehicle, and when it does not have the proper contour or shape, it can't properly hold the weight. Not to mention they have to be able to provide a certain amount of sidewall deflection under harsh conditions. The best analogy I can think of is this.
    Imagine you grab a gallon of milk and hold it to your chest. Pretty easy? You can hold it there all day. But when you extend your arm all the way out, you might have about a minute until you drop it. Tires are flexible and do have a wide range or rim widths they can fit on, and this is tested over and over during the manufacturing process. They figure out where the failure point is and then dial it back to create the chart that the TRA did. The most common ones are, any 22" chevy wheel has a 9.5" width and the most popular size was 305/40-22. This size requires a 10" wide wheel. And the other one was the chevy gmc 2500HD trucks. They all have 6.5" wide wheels and the most popular size people wanted is 285/75-16. But it has to be a 7" wheel. The TRA and others went back to look at the adjustment data(tire defects, blowouts, ect) and found that there was a very strong correlation between premature tire blowouts/tire failures and wrong application wheels and tires. If you go to any manufacturer website and lookup the tire size and the tire you want, it will tell you the range in which it fits. This is not BS just be smart and be safe. And for the love of god you spent 70k on a super car, don't be a cheap ass, buy the right wheel and tire setup that fits your needs. It will perform twice as good that way anyway. You do yourself no favors squeezing a 305 on there when a 295 will give you better lap times due to the fact its within the rim width range.
     
    • Agree Agree x 4
    • Like Like x 1
    • Winner Winner x 1
  2. SRT HC

    SRT HC BANNED

    Joined:
    May 11, 2015
    Messages:
    879
    Likes Received:
    315
    Trophy Points:
    213
    Location:
    Jacksonville, FL
    Vehicle:
    Charger SRT Hellcat
    Well, you started this. The stock Charger Hellcat tire doesn't seem to protude (bulge) enough to allow a parking mistake to rub the tire instead of curb rashing my wheel.

    I'm considering increasing to 285's to get a little more wheel protection (though probably not much)
     
    • Agree Agree x 1
  3. Tire God

    Tire God Hellcat Member

    Joined:
    Apr 5, 2016
    Messages:
    153
    Likes Received:
    30
    Trophy Points:
    18
    Vehicle:
    Challenger SRT Hellcat
    I believe 285s work on the stock 9.5" rim. That's what I would do. Or just stay away from curbs haha.
     
  4. VanishingPoint

    VanishingPoint Silver Member

    Joined:
    Jan 6, 2015
    Messages:
    917
    Likes Received:
    233
    Trophy Points:
    193
    Location:
    Somewhere, Texas
    Vehicle:
    Challenger SRT Hellcat
    And to add insult to injury, not all 275's are the same-even with the same load rating, and even from the same company. I have a set of 275 pirellis that a CLEARLY wider and rated the same weight/speed as our factory summers. YMMV lol.
     
  5. Tire God

    Tire God Hellcat Member

    Joined:
    Apr 5, 2016
    Messages:
    153
    Likes Received:
    30
    Trophy Points:
    18
    Vehicle:
    Challenger SRT Hellcat
    Correct. The section width actually varies from brand to brand and even tire to tire of the same brand. They have to be within certain limits though, but off the top of my head I can't remember the leeway. It's all in the 900 page long(or whatever) federal register from the NHTSA.
     
  6. DGatzby

    DGatzby Gold Member Hellcat Car Club HCC Charter Member Midwest Regional Pres.

    Joined:
    Jan 16, 2015
    Messages:
    2,905
    Likes Received:
    1,461
    Trophy Points:
    598
    Location:
    Twin Cities, MN
    Vehicle:
    Challenger SRT Hellcat
    Yep, I purchased two tires for another Hellcat owner a few months ago, their tread patches are different widths than the tires that came on my Hellcat one year ago!
     
    • Like Like x 1
  7. BIG DAWG

    BIG DAWG Hellcat, 1st Florida Cavalry Hellcat Car Club Gold Supporting Member HCC National Exec. Director HCC Charter Member

    Joined:
    May 4, 2015
    Messages:
    1,630
    Likes Received:
    1,020
    Trophy Points:
    563
    Location:
    Florida Panhandle
    Vehicle:
    Challenger SRT Hellcat
    I needed to change all four of my stock tires, so I just got a new hellcat...:rolleyes:...is that lazy or what? Let the pummeling begin!
     
    • Like Like x 4
    • Winner Winner x 1
  8. Bluestreak

    Bluestreak Senior Hellcat Member

    Joined:
    Mar 21, 2015
    Messages:
    53
    Likes Received:
    15
    Trophy Points:
    48
    Location:
    Long Island
    Vehicle:
    Charger SRT Hellcat
    The bolt pattern might be right but good luck getting them over them big things that stop the car. I guess you could put them on backwards and maybe they would still fit under the wheel well but it might look a little silly?

    Please tell me this isn't a serious question? And if it was, I didn't mean to, well maybe I did a little, demean you but there are so many dimensions to consider. Maybe leave what you have alone for a bit and when you blow out that $400 tire then you can replace it with whatever you want.

    My top speed (closed course, professional driver and all those legal things) was 173 mph. Before I even rolled I checked the air pressure in each tire, torqued each nut and gave the runway a good twice over. This isn't your fathers "Oldsmobile". Sorry to drone on but, but, 15 inch wheels? I don't think you can buy a Prius with 15 inch wheels, can you?

    [​IMG]
     
  9. SRT HC

    SRT HC BANNED

    Joined:
    May 11, 2015
    Messages:
    879
    Likes Received:
    315
    Trophy Points:
    213
    Location:
    Jacksonville, FL
    Vehicle:
    Charger SRT Hellcat
    This thread is finally getting to me. Where are the good ol' days when tires sizes made good sense. On my Magnum the rear tires are Mickey Thompson's are 28.00/12 x 18. Isn't simple: tire is 28" tall, 12" wide, and fits 18" wheels.

    Enter the today's crap. Tires are now 275/45 x 18. Simple? Not in the slightest. Why, them mix English and metric. Why??!! 275mm, well okay. Then to add a bit of complexity we have aspect ratio. Damn. Okay the sidewall is 45% of the width of the tread. Now for some odd reason, we throw in the English measurement system with 18 inches. Why not be consistent with 457mm? Pick one measurement system or the other!

    Not to mention the wheel sizing, when they got away from back spacing and gave us offset. Thanks again!
     
  10. Tire God

    Tire God Hellcat Member

    Joined:
    Apr 5, 2016
    Messages:
    153
    Likes Received:
    30
    Trophy Points:
    18
    Vehicle:
    Challenger SRT Hellcat
    The reason is because measuring in millimeters is alot more accurate than an inches. And it makes for alot more available tire sizes. If you can only fit a 33in tire on a truck because 35's rub, you have to put a 33 on it. But with the tire sizes available today, if a 34.5 fits, you can put it on instead. It gives manufacturers and customers alot more options for their vehicles. Because trying to do math on a 34.275x12.35-20 is not easy to figure out if it will fit. Hopefully this makes sense. The first number is the section width(when inflated on the rim) measured in millimeters, the second number is the aspect ratio or how tall the side wall is in relation to the first number. 40% of 275mm. And the last number being the diameter of the rim. As far as offset, backspacing is still used everyday. But for most applications, backspacing is not needed because it just tells you how far away from the suspension the back of the rim will be. I only have to look at that when fitting very old classics ect. But offset is easy. And it tells you where the wheel will be positioned and how flush with the fender it will be. A zero offset means that the back of the mounting pad (the part that is secured to the hub) is directly in the center of the wheel. And it's also measured in millimeters. So a positive 25 offset means it will be positioned 1in closer to the outside lip than a zero offset. So if your stock wheels are a 20×9.5 with a positive 25 offset, and you put on a 20x9.5 with a 0, the wheel is pushed out an inch closer to the fender. Backspacing is not that important because like in this example it's giving you 1 more inch of clearance for the suspension so the backspacing doesn't matter. What matters is, will it cause rubbing on the fender? Ect.

    Now about the charger steel wheel question, two things.
    1: why in the world would you want to put cheap, weak, ugly wheels on a HELLCAT?
    2: no it won't fit due to the massive brakes on the car. Not to mention if it were to clear the brakes you would have to put a tiny tire on it and would destroy the traction, handling, and safety of the car. Try to find a car with that much power or that can do 200mph with steel wheels. Bet you cant. It's like buying a Ferrari and wanting to put double coin brand Chinese tires on it that cost 50 bucks a peice instead of buying the michelin tire that cost 500 a peice that was specifically designed for your car. NO.
     
    • Like Like x 1
    • Winner Winner x 1
  11. FarAwayFromHere

    FarAwayFromHere Gold Member

    Joined:
    Aug 8, 2015
    Messages:
    1,417
    Likes Received:
    443
    Trophy Points:
    218
    Location:
    CA-NA-DA
    Vehicle:
    Challenger SRT Hellcat
    forget I even asked!
     
  12. Tire God

    Tire God Hellcat Member

    Joined:
    Apr 5, 2016
    Messages:
    153
    Likes Received:
    30
    Trophy Points:
    18
    Vehicle:
    Challenger SRT Hellcat
    If it's for a winter setup, buy a set of all season or snow tires in the correct size. And when summer comes back around, put the summer tires on. Discount tire does free winter change overs for the customers that buy their tires from us. Dont be upset, I'm not bashing on you like (someone else was) but my statement is true. Don't put horribly wrong fitments on your very nice car. It won't fit, and if it did it's not safe. Period.
     
    • Like Like x 1
    • Agree Agree x 1
  13. SRT HC

    SRT HC BANNED

    Joined:
    May 11, 2015
    Messages:
    879
    Likes Received:
    315
    Trophy Points:
    213
    Location:
    Jacksonville, FL
    Vehicle:
    Charger SRT Hellcat
    Well, I can see we won't see eye to eye on either.

    Question: What tire width is between 275 and 285. What I am asking is, what is the exact width of a 285 tire? It looks like tire widths are in 10mm intervals. So, I'm guessing that a 285 is between 280mm and 290mm wide. If that is true, the aspect ratio will make the tire height calculation less accurate.

    Sure, 10mm intervals are more precise than 1 inch intervals. I don't see why tires can't be marked to the nearest tenth of an inch. But maybe that would be confusing to read.

    Disclaimer: I am extremely good at math, so these arithmetical tire calculations are simple for me. My biggest concern is the precision of the tire claimed measurements, is a 275 tire exactly 275mm and if not, what is the variation from the claimed target?
     
    Last edited: Apr 12, 2016
  14. FarAwayFromHere

    FarAwayFromHere Gold Member

    Joined:
    Aug 8, 2015
    Messages:
    1,417
    Likes Received:
    443
    Trophy Points:
    218
    Location:
    CA-NA-DA
    Vehicle:
    Challenger SRT Hellcat
    Not Upset lets get that out of the way!
    Just an FYI I have 15 years experience working with auto/truck/equipment/implement tires specifically!
    I Value all opinions offered and can make,informed decisions based on them.
    Running 18" IMHO would be satisfactory in winter!
    As long as they fit over calipers!


    Far
     
  15. Tire God

    Tire God Hellcat Member

    Joined:
    Apr 5, 2016
    Messages:
    153
    Likes Received:
    30
    Trophy Points:
    18
    Vehicle:
    Challenger SRT Hellcat
    They won't fit over the calipers. The rim width and offset are completely wrong. It really is like standing with your feet apart and someone trying to push you over vs with your feet together. The car is a very finely tuned beast. I wouldn't recommend messing with it.
     
    • Useful Useful x 1

Share This Page

Search tags for this page

2016 chalenger wide wheels

,

2016 challenger tires wrong size

,

challenger biggest tire on 11 inch wheel