Sugarmaker wrote: ↑Sun Jan 14, 2024 10:04 pm
On the tires I would like to do this:
- Want to keep the Magnum 500 wheels if possible. I think they are 7 inch wide rims. Not sure the backspacing dimension?
- Get at least 1/2 inch more clearance in the front tire to fender clearance ( now about 1/4 inch) That means a smaller diameter tire.
- On the rear and or the front I would not mind a wider tire look, but not sure the driving clearance is there? I have about 1 inch clearance on both sides of the rear tires (inside and outside) This is with the shocks at 80 PSI.
So maybe a 215 size tire might be a good option? Could I go wider??
First, a disclaimer: I'm a retired engineer. A large part of my career involved using spreadsheets to analyze and optimize projects. I just can't help myself. It's in my DNA.
With that confession out of the way, I looked at a range of tires that would fit your rims, and how they compared in diameter and width. First, a little tire tech:
The "official" dimensions for a tire are based on that tire being mounted on a rim of the width that the tire was designed to run on. That is called the standard rim, or measuring rim. The tire can still safely be mounted on narrower or wider rims, within limits, but that affects the actual mounted width of the tire. The actual installed tire width will change 2/10" for every 1/2" the rim varies from the measuring rim width. In your case, your 225/70/14's are 8.9" wide when mounted on a 6.5" wide standard or measuring rim. Since you have them mounted on 7" rims, they actually measure 9.1" wide.
Another thing to note is that I wasn't able to find an online source for 14" 65 series tires. It appears your options are confined to 70 or 60 series, and the 70 series only goes up to 225/70/14. That said, I put together a spreadsheet.
Since you're looking for 3/4" of clearance between the front tire and the fender, the 205/70/14 is the only 70 series that will add an additional 1/2" to your existing 1/4" to accomplish that. Any of the 60 series tires will easily do it. However, even though the 235 would give you the straight ahead clearance you want, it could still possibly touch the fender when turning the wheels. Think of the latch side of a door closing in a door jamb. That side of a door is chamfered at an angle so it won't strike the jamb as it swings shut. You can't do that to your tires, and the wider the tire, the greater the chance of interference. You also have an increased chance of the tire contacting the frame rail and/or the fender well at the rear of the front tire. Depending on the backspace of your wheel, you could also have problems contacting the upper control arm with wider tires. For what it's worth, I have 215/65/15's on 7" rims with 3.75"BS on the front of mine, which are .4" smaller in diameter and .39" narrower than your 225/70/14's, and I occasionally scrub the fenders making a turn with a dip in the road, and scrubbing the back of the fender well and frame rail when turning the wheels all the way, like when parking. I should have gone with 205/65's or 205/60's.
In the rear, if you've got 1" clearance on both sides of your current tires, you could go with up to 245/60/14 (biggest I could find). That would lessen your gap on each side by .3", but that might be pushing it. Probably better to go with 235/60/14's and only take an additional .1" on either side. I have 235/60/15's with the same wheels as on the front on the back of mine and have no problems with rubbing. Some on here have said I must have a narrowed rear axel to get away with that, but I don't. I think my stance is just a little higher than theirs, which is what you're accomplishing with your air shocks.
My advice (and worth every penny

) is go with 205/70/14's on the front and 235/60/14's on the rear. The 235's have .1" less sidewall height and .2" less total height than the 205's, but you'd never notice that visually. If you wanted to go with 60 series on the front, I would not go above a 215/60/14. If you want to be able to rotate tires between front and back, I'd go with either the 205/70's or 215/60's all around.
Jim