Convo Pros on a 1957 Custom 300 Disc Brakes

[Dsmoothy1]

Good morning. I would like to put some Centerline Convo Pros our the 57' Custom 300 we are redoing. They offer a 15x8 and a 15x7. Please let me know what tire that you think I could stuff under it using either wheel combination. I wanted to put something like a Mickey Thompson Et Street legal tire on the back, but it is ok if I am just going to put the same tire all the way around! Thank you so much for the help!

15X7   5X4.50   5x114.3    -6 offset(MM)   3.76 Back Spacing  or

15X8   5X4.50   5x114.3     0 offset(MM)   4.5  Back Spacing   

https://centerlinewheels.com/wheel/000-convo-pro/?cat=56

[lalessi1]

The 8" wheel with 4.5" BS will not work on the rear of a stock '57. A 7" wheel with 4.25 is a tight fit. I have 15 x 8 wheel on the rear of my Custom with 5.25" BS and with 275/60 15 Cooper tires. The tires will rub on the outside of the inner fender well occasionally and they are abought 1/2" from the spring on the inside. My quarter panel lips are also "trimmed". On the front I have 15 x 7 with 4.25" BS with 235/60 15 tires and they are pretty close to the spindles but no issues.

For reference, my car has 6" leaf springs in the rear and 2" lowering blocks. Clearance was better with 1" blocks. I would say 15 x 8 with 5.125" BS and 255/60 tires is about the max without modifying stuff.

Wheels and tires are a challenge on our cars when you are looking to go wide...

BTW welcome to the forum!!!!

[RICH MUISE]

If you have plans to modify the rear case, shortening by 5/8 per side will help, as will changing to disc brakes. Using '56 shocks in the rear will allow the rear end to drop far enough to remove the tire, otherwise, you may have to undo the shocks to get enough clearance for tire removal.
Welcome!! I like your wheel choice, not sure offhand what backspace is on my 15" wheels without checking, offhand I think 7" w/ 4.25 bs. I'm using Rocket Igniters.  I have done what I mentioned above and have zero issues removing a tire. (235/70/15

[Dsmoothy1]

Such amazing information! Thanks so much!

[RICH MUISE]

A few added notes.if you do narrow the differential case, the end "caps" are available in big bearing, old pattern, or later model pattern. I mention this because, if you do go to rear discs, decide on which kit you will be using to determine WHICH bolt pattern it is made for. Discs make it a little easier on tire changes because it's easier to get the wheel past a rotor than a drum.

[Dsmoothy1]

The car has this brake system on it. I don't think either Convo Pro will work. We might just go with some new Cragar SS Wheels. I was just thinking that the Convo Pros would be a little different. Thanks!


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