What is proper size magnum?

[still]

Looking for correct size magnum rim fr a 68 Newport??? Not sure what size was on the 300??? Best I can tell it would be a 14 x 6.? Worried about rim size with wheel skirts. Any input? Thanks Steve

 

[MrMoparCHP]

The size difference should not be an issue. If you step up to a 15 you just need to step down one other factor. So if you have 75's on change to 70's or if you have 235's change to 230's and everything else should be fine. This is the old school rule of thumb.

Unless you are making major changes you should be fine.


Alan

 

[polara71]

To be correct I believe 14 is the answer and I want to say 5.5. I'm certain the slab guys will be along shortly

 

[cbarge]

The original 1968 factory Magnum 500's were 14X6.
The later "cheaper" version painted road wheels with trim rings were 5.5" wide
For your car,Wheel Vintiques offer a 15X7 Magnum 500 with a 4.25 inch backspace.
Optimum tire size for the 68 Chrysler in a 15 is 2357015
28 inches tall--same as the factory bias ply 8.55-14 tires.
Alternative size suggested is 22575R15
No broad market tire manufacturers make a 14 inch radial tall enough to match the outer diameter.
Coker offers 2257514 American Classic radials but very expensive.
I ran the 2357015's on my 68 NYer and will be doing the same on the BoaB.
My NYer with 15X7 Mirada wheels,2357015's


Hope this helps

 

[polara71]

and there it is

 

[cbarge]

Forgot to mention,plenty of room outback for the bigger rubber even with the skirts.
Keep in mind backspacing is important.
Rule of thumb 3.75 to 4.25 on a slab
Going wider means going inward more to stay clear of the skirts.

 

[live4theking]

On my 68 NYer I've got 15x7 steel wheels, I'm not sure of the backspacing. I've got 255/60R15 cooper Cobra's on them. According to Cooper's website they are just over 27" tall. Even with the extra width they turn lock to lock up front and there is plenty room in the back.

 

[cbarge]

On my 68 NYer I've got 15x7 steel wheels, I'm not sure of the backspacing. I've got 255/60R15 cooper Cobra's on them. According to Cooper's website they are just over 27" tall. Even with the extra width they turn lock to lock up front and there is plenty room in the back.

View attachment 67813

Your tire size is acceptable,but a bit small in diameter.However,they will give the car a nicer ride and lower the center of gravity. Wider rubber will always give a slab a smoooooth ride!
If she has 2.76 gears,the smaller tire will work like 3.0ish ratio.
You may have already noticed a little more pick up from the line,yet the speedo will read faster than what a GPS will read,and the engine will rev a few hundred RPM's higher on the freeways.
Nothing wrong with any of that,just an occupational hazard since I work in a tire shop,LOL!!

 

[live4theking]

Your tire size is acceptable,but a bit small in diameter.However,they will give the car a nicer ride and lower the center of gravity. Wider rubber will always give a slab a smoooooth ride!
If she has 2.76 gears,the smaller tire will work like 3.0ish ratio.
You may have already noticed a little more pick up from the line,yet the speedo will read faster than what a GPS will read,and the engine will rev a few hundred RPM's higher on the freeways.
Nothing wrong with any of that,just an occupational hazard since I work in a tire shop,LOL!!

Thanks for the info.

 

[WorkerBee]

Looking for correct size magnum rim fr a 68 Newport??? Not sure what size was on the 300??? Best I can tell it would be a 14 x 6.? Worried about rim size with wheel skirts. Any input? Thanks Steve

The 14x6 chromed styled road wheel (Magnum) wasn't available on the '68 Newport, but they sure do look good on the Slab Side C's. I personally would buy the 15x6 size, to give it a stock skinny tire look.

As far as factory sizing, the C-Body got the 14x6 chromed styled road wheel available only in '67&'68.
B-Bodies had 14x5.5 chromed styled road wheels for '67&'68 and the W23 styled road wheels with trim ring was 14x5.5 also....up to 1974.

 

[commando1]

The original 1968 factory Magnum 500's were 14X6.
The later "cheaper" version painted road wheels with trim rings were 5.5" wide
For your car,Wheel Vintiques offer a 15X7 Magnum 500 with a 4.25 inch backspace.
Optimum tire size for the 68 Chrysler in a 15 is 2357015
28 inches tall--same as the factory bias ply 8.55-14 tires.
Alternative size suggested is 22575R15
No broad market tire manufacturers make a 14 inch radial tall enough to match the outer diameter.
Coker offers 2257514 American Classic radials but very expensive.
I ran the 2357015's on my 68 NYer and will be doing the same on the BoaB.
My NYer with 15X7 Mirada wheels,2357015's


Hope this helps

And this is why I've been wanting to drag you over to this place.
Show these guys your library.

 

[cbarge]

And this is why I've been wanting to drag you over to this place.
Show these guys your library.

I don't think there is enough data room to handle it!!
Ha HA HA!!