Slant Six Forum :: Max tire size / offset for 71 Swinger with 15" x 7"

I am a little confused with the backspace/offset measurments. Wouldn't a 4.5" backspace with a +12 mm offset give you an effective 4.1" backspace?

Quote:

I am a little confused with the backspace/offset measurments. Wouldn't a 4.5" backspace with a +12 mm offset give you an effective 4.1" backspace?

Offset puts the mounting pad (or lug plate) in a certain position in relation to the center of the wheel width. THEN backspace is measured from the mounting pad.

Thanks for clearing that up for me.

If it is too tight I will probably just go with the 225 on back, 215 on front, and just eat the ability to rotate.

That aught to look really good, and handle well also. Post us a photo when you get them on. How fast do you intend to run. I have Michlin MXV4's on my '69 and like them very much. I would be tempted to put the smoothie hub cap on. Are they included, or do you have to oreder them extra?
Sam

Thanks for clearing that up for me.

If it is too tight I will probably just go with the 225 on back, 215 on front, and just eat the ability to rotate.

Actually, when I was trying the 3.5 backspace rim with the 225's, the critical area was on the lower front corner of the outside of the wheel well.

I have 4 225s and 2 215's set aside at a local tire place

I will say, my car handled the best with cop car wheels.

Sam

Author:	AnotherSix [ Fri Jul 07, 2006 9:16 am ]
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I have been shopping at Summit as well. I ordered their brand of aluminum 15" x 7" with 4" backspacing, they are $99.95 which is not bad considering the other choices in aluminum. If you go to steel and are concerned only with function, like for an autocrosser, the Crager "soft eights" can be had in just about any width and backspace you want, chrome or painted, for between $35 and $65. They even have 16". I have not found weight specs for them but they may be close to aluminum. Now I just need tires, I am leaning toward a 215 - 60 now. If I had the car here to do some measuring this would be allot easier. My plans for the car include heavy suspension and cornering so I totally agree that "just barely fit" is not good enough. Everything moves quite a bit when the cornering force increases.

Author:	slantvaliant [ Fri Jul 07, 2006 9:39 am ]
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Cragar: http://www.cragarwheel.com/catalog_pg8.html Unique: http://www.uniquewheel.com/catalog_pg4.html Use the "Click here for details" to get specs. BTW, what is the relationship between these two companies? The wheels look the same to me.

Author:	RossKinder [ Fri Jul 07, 2006 2:58 pm ]
Post subject:
Quote: I am a little confused with the backspace/offset measurments. Wouldn't a 4.5" backspace with a +12 mm offset give you an effective 4.1" backspace? Offset puts the mounting pad (or lug plate) in a certain position in relation to the center of the wheel width. THEN backspace is measured from the mounting pad.

Author:	RDJ [ Fri Jul 07, 2006 3:29 pm ]
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Quote: Quote: I am a little confused with the backspace/offset measurments. Wouldn't a 4.5" backspace with a +12 mm offset give you an effective 4.1" backspace? Offset puts the mounting pad (or lug plate) in a certain position in relation to the center of the wheel width. THEN backspace is measured from the mounting pad. Thanks for clearing that up for me. I ended up ordering the Cragar 313 Chrome Smoothie from Jegs today ($56), 15X7, 4 1/8 backspace. They will be here next Tuesday. I will update you on how the 225/60/15 fit on the front with more backspace. If it is too tight I will probably just go with the 225 on back, 215 on front, and just eat the ability to rotate. One bonus with the smoothie is I don't have to buy center caps or lug nuts.

Author:	Sam Powell [ Fri Jul 07, 2006 7:32 pm ]
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That aught to look really good, and handle well also. Post us a photo when you get them on. How fast do you intend to run. I have Michlin MXV4's on my '69 and like them very much. I would be tempted to put the smoothie hub cap on. Are they included, or do you have to oreder them extra? Sam

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Max tire size / offset for 71 Swinger with 15" x 7" https://slantsix.org/forum/viewtopic.php?t=18379	Page 2 of 2

Author:	RossKinder [ Fri Jul 07, 2006 7:56 pm ]
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Quote: Thanks for clearing that up for me. Quote: If it is too tight I will probably just go with the 225 on back, 215 on front, and just eat the ability to rotate. You refer to smaller tires only at the front . . . I could probably get hung by my thumbs for saying this, but if you're concerned that turning could rub the frame it isn't inconceivable that you could put in spacers to set the whole thing out on the front . . . Depending on . . . I don't remember what car you're talking about. Stud length and size would be a factor, as well as whether you needed to go out a whole .5" and if you'd be getting into an outer rub. I'm talking concepts here. I can't offer specifics on engineering. Of course you probably already plan to try out some 225's on the front before you buy 215's you may not need.

Author:	RDJ [ Fri Jul 07, 2006 8:25 pm ]
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Quote: That aught to look really good, and handle well also. Post us a photo when you get them on. How fast do you intend to run. I have Michlin MXV4's on my '69 and like them very much. I would be tempted to put the smoothie hub cap on. Are they included, or do you have to oreder them extra? Sam The rims come complete with the smoothie hubcap (I think, It better!). I will post a photo when I get them on, but keep in mind I haven't done the body yet. I just got it running a couple of weeks ago with a 1 bbl, put the 2 bbl on last weekend, got the exhaust done on Tues. When I get the tires/alignment, I will put on my front sway bar (already have the new 5 leaf on the back and new KYBs all around). I have kind of a heavy foot, and the engine has a cam, bored over, 9:1 compression, so I do want it to handle. I am starting the body work tonight, just dings and dents, but it is over 100 degrees here today, so I will work at night, cause I suck at bondo. I am putting on the BF Goodrich radial TAs. By the way, my wife was looking at this site and loves your car (so do I) quote="RossKinder"] Quote: Thanks for clearing that up for me. Quote: If it is too tight I will probably just go with the 225 on back, 215 on front, and just eat the ability to rotate. You refer to smaller tires only at the front . . . I could probably get hung by my thumbs for saying this, but if you're concerned that turning could rub the frame it isn't inconceivable that you could put in spacers to set the whole thing out on the front . . . Depending on . . . I don't remember what car you're talking about. Stud length and size would be a factor, as well as whether you needed to go out a whole .5" and if you'd be getting into an outer rub. I'm talking concepts here. I can't offer specifics on engineering. Of course you probably already plan to try out some 225's on the front before you buy 215's you may not need.[/quote] Actually, when I was trying the 3.5 backspace rim with the 225's, the critical area was on the lower front corner of the outside of the wheel well. It looked OK until the tire was turned, and the corner/edge of the tire barely missed that corner. I was thinking that if I got the wheels with more backspace, it would be clear. I have 4 225s and 2 215's set aside at a local tire place, and they have great freindly service. Their attitude is "I get paid by the hour, so take your time". Frankly, it would probably look better with the 215's on front, but tires are pricey and it is good to make them last.

Author:	RossKinder [ Fri Jul 07, 2006 8:50 pm ]
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Quote: Actually, when I was trying the 3.5 backspace rim with the 225's, the critical area was on the lower front corner of the outside of the wheel well. I'm starting to wonder if I'm the only one who ever had problems with inside clearance. Quote: I have 4 225s and 2 215's set aside at a local tire place A man with a plan!

Author:	RDJ [ Wed Jul 12, 2006 9:08 pm ]
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I went with the 225/60/15 on the front (and back). It is close when the wheel is turned (about 2-3 pencil widths), but hasn't rubbed or anything. Here are some pics (also one of my new engine installedl), also there are pics of my former White Enamel Hot Wheels Custom Camaro I sold a while back (almost $800!) http://pg.photos.yahoo.com/ph/rdjudge@s ... ?.dir=caeb I don't know how to post pics yet, but this link will get you there.

Author:	RossKinder [ Mon Jul 31, 2006 3:27 pm ]
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Quote: I will say, my car handled the best with cop car wheels. Sam Do you think maybe the metal is stronger (maybe thicker?) on these? My dad had a 2 ton truck and the wheels kept cracking at the lug holes. Then he discovered that they made wheels for it with much thicker metal and put them on. Problem solved. Elsewhere I read about hub caps creeping. That sounds like flexing in the (soft) wheels to me. Flexing could also effect handling, right?

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