275/45/17 ??

[LS6 Tommy]

OK. The test fit for my new 17" x 8" wheels is done. Everything fits around the suspension & now I'm ready to get the wheels painted & order tires. I'm going to go with 245/45/17 on a 5" backspacing for the front, like 35579_bu did because we have the same front suspension. I was going to run 255/50/17 on the back with a 4.25" back spacing, but I'm starting to think maybe a wider tire that maintains the same diameter will look nicer. Anyone running 275/45/17 on a stock width axle with no frame or fender well mods?

Tommy

 

[Doober]

I remember someone on here had 275/40/17s on 4 17x8s, but I can't remember his username for the life of me and I'm not sure if he had to do anything to the lip or not. malibu795 was doing fitment, etc. checks on his with 17xx wheels and tires.

 

[malicad]

I don't think that a 275 is recommended for an 8" rim...I think the minimum rim width is either 8.5 or 9.

 

[Doober]

Looking at Summit's site it appears you're correct. I looked up 275/40s and they say minimum recommended width is 9", 275/60/15s however are 7.5"... I'm no tire expert but it seems like minimum width goes up with aspect ratio... so I'm guessing it may be possible with 275/45s, if they make that size.

 

[Randy W]

@75/40/17 rear, 245/45/17 front, 8" wheel zero offset.

 

[malicad]

Didn't say it couldn't be done. It just shouldn't be done. Not safe. Could probably physically mount up a 275/40 17 on a 6-inch wheel and get it to bead up. I wouldn't want a ride in the car though. As aspect ratio goes down (like from a 55 series to a 35 series), recommended wheel width goes up (like from 6 to 8 inches) to compensate for the lack of flexibility in the sidewall. Not TOO proud of this, but I'm certified my Michelin, Cooper, Starfire, BF Goodrich, Uniroyal, and a few others. I had to take a ton of their tests and get certified as an "expert" for my job. Used to sell tires, now I'm a manager.

 

[Randy W]

Well, Mr. Expert, before I did it I talked to tech at Goodrich/Michelin 2-3 times and was assured that with proper pressures it was absolutely safe and would wear and handle as it should, and viola, they were right! They told me that wheel width recommendations were based on what they called sweet spots in rim/tire combos and there was at least a 10% safety margin. If you take 9" and subtract 10%, you get 8.1", If you take a Boyd's Smoothie 2 and measure between the beads, which we did, the "8" inch wheel is actually 8.25". So before you jump into an argument that didn't exist before you jumped in, know what you're talking about. You're welcome. :mrgreen:

 

[malicad]

Think what you want. I know I'm right. The acceptable rim widths are listed in their catalogs, but all the measurements they give as far as height, tread width and sidewall height are taken from their "sweet spot" rim, or "meausred rim width" to make everyone's measurements the same. looking at a BFG catalog, say a rim range of 8-10", and look a little deeper, they have a column for all the measurements (sidewall height, tread width, etc...) from that particular tire mounted on a 9.5 inch rim. That's what they actually recommend mounting the tire on. Your "roughly 10 percent" is why they have a column stating the tire could work on an 8 or 10 inch wide rim. I've been going to tire seminars and talking to BF Goodrich reps and techs, and driving their cars they bring to showcase new tires to for 15 years, so, I do know what I'm talking about when it comes to tires. I'm trying to keep everybody safe, and not have any tires dismount themselves, because they MAY have been improperly mounted. I've seen it personally. Didn't mean to start a fight.

 

[LS6 Tommy]

I'm most likely going with the 255/50s. 275/40s are too short. I want a 27" tire & I can't find any good performance 275/45s. Mostly truck tires.


Thanks for all the input!

Tommy