Tire and Rim Sizing on a 90's GM B-Body

Discussion in 'General Automotive Tech' started by Cyber-Wizard, Jan 22, 2012.

  1. Cyber-Wizard

    Cyber-Wizard Well-Known Member

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    I've been looking at putting a flashier set of rims on my '94 Roadmaster wagon. I love the stock look of my Roadie Aluminum's but they're a little bit rough. I've been thinking about Impala SS rims, which are 17" or perhaps a set of Torque Thrust 2's, or one of the various clones of TT2's. I like the idea of staying with 15" so that I don't impact that cushy ride in any way. I definitely won't get rid of my current rims, I just want to try a change for a while.

    I'm having some trouble determining just what will and won't fit on my car. I've located a seller with some Eagle Alloy rims (pic below) that I sort of like. The price is good but they're a couple of hours away in Barrie so I can't just swing by and take a look at them. The bolt pattern is right, of course, but they are larger than what I'm running now. I have 225/75R15's on 15x7 rims. He's selling a relatively new set of BF Goodrich 235/70R15's Radial TA's on 15x8 rims for $800CDN. He claims that they're fine for a Caprice but I prefer learning things for myself (Or at the very least asking here where I know I'll get a good answer). I've looked at several tire sizing forms on the web and I don't think I'll have any problems. I think most of us know that I'm more than a bit of a noob so I'm not entirely sure that I came to the right conclusion. Had anyone found a good resource for learning about tire/rim sizing and what directions you can grow/shrink into without issues?

    [​IMG]
     
  2. Blackfoot

    Blackfoot Wagonless Soul

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    If you go up in width buy one number and go down in profile by one number, the size is almost identical. With the 1 inch wider rim, you might be a 1/4 inch shorter in height.

    They will fit fine. I have run 235/75/15s all the way around my Roadie, never any issues other then at full wheel lock it would very slightly rub on the frame when the suspension was compressed while moving and turning right, but never rubbed when turning to the left. You will hate those BFG Radial TA's if you ever get caught in any freak snow when running them. I had them on my '01 Grand Am and they were as useless as tits on a flea in the snow and they only lasted me 1 summer of 14k miles and they were wiped out all the way around the car, I even had it aligned it myself on our FORD dealership laser machine 3 times and each time it was dead on. The next set I bought were Firestone Firehawks Indy 500's and they lasted me 42k driving year round and they were awesome in the snow. But for $800 on those wheels, thats a decent deal, you are looking at $1300-1500 for the same setup new.
     
    Last edited: Jan 22, 2012
  3. Cyber-Wizard

    Cyber-Wizard Well-Known Member

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    Thanks for the info! I think I'll go through with it.

    I had my doubts about the tires. He said they were almost new but the tread wear photos don't match up. Sounds to me like they wear out pretty fast so maybe that's accurate. I figured I could sell them off and keep the rims or run them for a year before buying something I like better. Its the rims that im after The Roadie's a summer cruiser and I'm a huge fan of the Michelin Hydroedge i had on my Grand Marquis so I imagine a set of those will wind up on the Buick eventually.
     
  4. Fat Tedy

    Fat Tedy Island Red Neck

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    Yup, BFG's are the worst tire IMO also when it comes to any ice or snow. They are a soft tire = a more comfey drive, they are definatly not a preformance tire. I have had several sets over the years and have allways gotton a fair mile out of them but I also don't drive like when I was in my teens anymore
    :character0182:

    PS, I like the mags!
     
  5. Cyber-Wizard

    Cyber-Wizard Well-Known Member

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    I got a notification that FastPhil had posted a comment to this thread. I came to reply and there's no sign of his post. Whatsupwiththat?

    I'm getting really excited now. The rims are about 2 1/2 hours away but we'll make a road trip out of it. I know that I can fit four tires in the trunk of my Parisienne from when I bought the snows a few months back. All I need to do is figure out how to get my trunk open. The key is pretty sticky at the best of times and lately hasn't worked at all. An oddity in an internal electrical circuit has my power trunk release turning on my dome light instead of releasing the trunk. :confused::huh: I guess I'll have to find some way to get it open before Saturday.

    I'm really looking forward to sitting down and getting those rims cleaned up and shiny. Even if I just get a season out of the tires that are on them it's still a decent deal.
     
  6. Cyber-Wizard

    Cyber-Wizard Well-Known Member

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    Here's a little photoshopping that I did of some Ridler's back when I first started thinking about shopping for rims. Now I'm even more excited.

    [​IMG]
     
  7. Cyber-Wizard

    Cyber-Wizard Well-Known Member

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    I picked up those rims on Saturday. the Mrs and I left around 8:00AM to get up to the sellers house by 11:00AM. The weather sort of teased and taunted all the way up just enough to keep the drive from being enjoyable. The sellers house was very much like the photo of his living room above. He had a Grand National and a '68 Chevelle out in the car port and almost every horizontal surface of the house that I could see was covered in car parts in various states of repair. These two guys were automotive die-hards.

    I had forgotten that these tires were wider than the snows I purchased for the Pontiac so I wasn't able to get all 4 in the trunk with the spare this time. I wrapped one in a blanket and put it in the back seat. It was kinda crappy out yesterday so I haven't dragged them out of the car yet for pics. They were in better shape even than the sellers pics indicate. I don't think there were any marks on any of them and the tires are decent enough to get at least a season out of them. All they really need is a GOOD cleaning. 6 1/2 hour drive aside, it was a pretty good deal. Spring can't come soon enough for me! :dance::29:
     
  8. silverfox

    silverfox New Member

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    Fast Phil deleted his own post. :D You can PM him about it, though.
     
  9. jmt455

    jmt455 Well-Known Member

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    I've used this one many times: http://www.miata.net/garage/tirecalcold.html

    You enter the two sizes you are considering and it gives you comparisons of all the key dimensions.

    Doesn't really help with fitment in your specific vehicle, but it gives a quick comparison of sizes.
     
    Last edited: Jan 30, 2012

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