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Discussion Starter #1 (Edited)
If you HATE the way they size tires.. Even if you know metrics well, you
still do not know exactly what the sizes of the tires are.. Now you do..
The TOP chart is all 17" tires and wheels..



1. Section width varies approximately 0.2" (5mm) for every 0.5" change in rim width.

2. The sizes shown are average design values for tires measured on specified measuring rim widths.

3. These should all fit on the 7" wheel..

4. Use these charts at your own risk..

This chart has smaller 17" tires
and includes a couple of 18" tires and wheels..

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this just makes it a little easier when you are planning on putting different
tires on your Challenger to see at a glance what size is what..
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If you need just a little more room to install wider tires..

click this link: 5/16" wheel spacers
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My car has 225/65/17 in front & 255/70/17 in back
 

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Diameter is easy! The first number is the nominal case width. For example 245. The next number is the cross section ratio. For example, 45. The last number is the wheel diameter. The cross section ratio is simply a percentage of the width. 245/45 means a height of 110.25mm (multiply 245 by 45%). Divide by 25.4 (number of millimeters in an inch) equals 4.34 inches. That's the sidewall height. Multiply by 2 to get 8.68. Add it to the rim diameter to get 28.68. Looking on TireRack, I find that the advertised diameter for the Goodyear 245/45R20 size is 28.7 inches. Close enough!

Width is a bit trickier. The case width versus tread width depends on the sidewall cross section. A 60 series tire has less tread width than a 45 series tire since it bulges more at the sidewall. The Required rim width for a tire changes depending on the tire manufacturer. For a 45 series tire, the ratio is about 1.2 of nominal case width. Divide 245mm by 1.2 to get 204mm. Divide by 25.4 (mm to inch conversion again) to get 8.03 inches. Nominal rim width for that same Goodyear is 8.0 inches which is again, close enough.

Desired rim width is usually .5" smaller to 1" wider. You can mount a tire on a wider than desired rim as the case will gain strength slightly and have less tendency to tuck under as the beads are spread slightly wider. If you put a wide tire on too narrow of a rim, the beads being too close together will give the tire more of a tendency to tuck under and can lead to unseating a bead. Goodyear recommends a 7.5-9" wide rim for that same 245/45R20.

Hope that helps!
 

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Discussion Starter #3 (Edited)
Diameter is easy! ....
Width is a bit trickier. !

and you don't think it is easier to say

30" x 9" .?

since most of the Challengers are sold in a country that uses
Imperial measurements on most everything else..
 

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Your chart was only showing some 17's so I thought I'd throw in the way to figure diameter and width off of any tire size as well as way to figure rim width (ballpark). Sorry.
 

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Discussion Starter #5
Your chart was only showing some 17's so I thought I'd throw in the way to figure diameter and width off of any tire size as well as way to figure rim width (ballpark). Sorry.
No problem..

No worries..
 

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Not a bad chart. I am considering going with 245/55-18 tires on the stock G-package wheels. Same diameter as stock. Probably BFGoodrich.

Agreed RudeMoody, I saw his car on another forum and loved it. I'm not to fond of tall tires though, but if I could find white lettered tires in a more stock size, even on the 17" wheels, I'd consider not getting the G-package.
 

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Question for ya Deserthorizons,

What was the effect on the car/computer but having a tire that was 2" taller in the rear?

I actually want to go with a tire that has a diameter of about 27.2. but am a bit afraid of the computer.
 

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Discussion Starter #9 (Edited)
ChallengerPhil said:
What was the effect on the car/computer but having a tire that was 2" taller in the rear?

Actually the tire is 3" taller than stock (28" vs 31")

The main effect is the cruise control won't work above 55 mph..
It either shuts off or won't turn on above 55 mph ..
This is caused by having 2 different size tires.. 28" in front and 31" in back..
If I put the 31.1 all the way around, it would work as normal.
The same exact thing happens if you use a space saver spare tire..

Secondly the speedometer is off by ~about 12%
It shows slower than actual speed..
Benefit is it registers 12% less miles than actual mileage..

If you go with smaller tires (27.2) the opposite is true.
Your speedometer will read faster and you will ring
up more miles than actually traveled..
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Discussion Starter #10
I am considering going with 245/55-18 tires on the stock G-package wheels. Probably BFGoodrich.

but if I could find white lettered tires in a more stock size, even on the 17" wheels, I'd consider not getting the G-package.
The selection of 18" tires with white letters is almost non-existant..
That was one of the deciding factors on my going without the G pkg..
I knew the look I was going for would not be possible..
(besides, there was nothing on the G pkg I wanted, even if it were free)
(except the wheels)
 

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Tire Height

Actually the tire is 3" taller than stock (28" vs 31")

The main effect is the cruise control won't work above 55 mph..
It either shuts off or won't turn on above 55 mph ..
This is caused by having 2 different size tires.. 28" in front and 31" in back..
If I put the 31.1 all the way around, it would work as normal.
The same exact thing happens if you use a space saver spare tire..

Secondly the speedometer is off by ~about 12%
It shows slower than actual speed..
Benefit is it registers 12% less miles than actual mileage..

If you go with smaller tires (27.2) the opposite is true.
Your speedometer will read faster and you will ring
up more miles than actually traveled..
.
.
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Does anyone know how much taller the tires can be in the rear than the front and still be able to fully use the cruise control ?
 

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The selection of 18" tires with white letters is almost non-existant..
That was one of the deciding factors on my going without the G pkg..
I knew the look I was going for would not be possible..
(besides, there was nothing on the G pkg I wanted, even if it were free)
(except the wheels)
I love the look of your Challenger... that's old school! :thumbsup:
 

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I have a 2010 Challenger SE with P215 65R17 all the way around..stock. I'm preparing to do some tire..possibly wheel changes and I want a classic muscle car look like what you have done. Is there anything different you would do if you had to do it again? Did you use 5/16" spacers on the front and back wheels? What brand tires did you go with?
 

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Discussion Starter #14
It all depends on if you insist on having white letters..
I did, so that determined the brand, and type of tire..
I have 17" also.. (there are NO white letters for 18" tires)
I have BFGoodrich Long Trail radials
255/70/17 in back = 31.1 x 10.25
and 225/65/17 in front = 28.5 x 9

They are actually a light truck tire, but it was the ONLY way to get the sizes I wanted in a white letter tire..
If I didn't want the white letter I had a thousand choices for tires..
But I would still go with a BFGoodrich tire.. They last forever..
I sometimes wish I had gone just a little taller and a little wider in back....

and NO spacers necessary.. I used the stock wheels..
There is a guy on one of the boards that tried some "Testors White Enamel Model Paint"
with very good results..
Next set of tires I am going to try that..
I now have over 40,000 miles on these tires and it looks like I still have another 30,000 left of tread..
 

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It all depends on if you insist on having white letters..
I did, so that determined the brand, and type of tire..
I have 17" also.. (there are NO white letters for 18" tires)
I have BFGoodrich Long Trail radials
255/70/17 in back = 31.1 x 10.25
and 225/65/17 in front = 28.5 x 9

They are actually a light truck tire, but it was the ONLY way to get the sizes I wanted in a white letter tire..
If I didn't want the white letter I had a thousand choices for tires..
But I would still go with a BFGoodrich tire.. They last forever..
I sometimes wish I had gone just a little taller and a little wider in back....

and NO spacers necessary.. I used the stock wheels..
There is a guy on one of the boards that tried some "Testors White Enamel Model Paint"
with very good results..
Next set of tires I am going to try that..
I now have over 40,000 miles on these tires and it looks like I still have another 30,000 left of tread..
Sorry for the off topic question but I gotta know.........
Are those side pipes/headers functional?? They look awesome!
(also sorry if this has been asked earlier)
 

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Discussion Starter #16
I gotta know.........
Are those side pipes/headers functional?? They look awesome!
Thanks !!
Yup.. check out my website:
challenger09
~$300.00 + 2 hrs labor to install.. (+ prep time)

also a lady from back east has them on her R/T

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Can I put 50 series tires on my S/E? I would love to add wider tires so that they will get max grip....I have the 21565R17 wheel on her now off a Charger. My stock tires sucked and Dodge agreed to change them. They caused me to "flow" while driving. In other words, when in the car you felt a swaying in the back end. They fixed it and it cost me nothing. Please advise what will fit on my Challenger....Thanks
Christine
 

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Can I put 50 series tires on my S/E? I would love to add wider tires so that they will get max grip....I have the 21565R17 wheel on her now off a Charger. My stock tires sucked and Dodge agreed to change them. They caused me to "flow" while driving. In other words, when in the car you felt a swaying in the back end. They fixed it and it cost me nothing. Please advise what will fit on my Challenger....Thanks
Christine
Sorry to dig up an old thread, but are you going to stay with 17" wheels, or what diameter are you going with? My 2013 SXT came with 18" 55 series tires, so that's almost to your goal.
 

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Need some help. If I want to put the old 18 inch rallye rims on my challenger that currently has 17 inch rims, what tires do you suggest/what came on these rims from the manufacturer?

These are the rims I am looking at, just for reference. Haven't really looked around for the best price yet so don't scold me if that's too expensive. Also I currently have P21565R17 tires. Basically looking for the same tire height.

Dodge Charger Challenger Magnum 300 18 inch Rallye Wheel Mopar | eBay
 

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You could put 225 X 60 X 18" on those rims with no trouble. That seems to be a dying tire size though. New Challenger's come with 235 X 55 X 18", which may be too wide for those rims being 7.5" wide.
 
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