How much tire to front fender clearance?

[71dusterdan]

Hey all been awhile since I've been trashing around. Rented a shop and got the car out of another Natures workshop, so I have been far too busy building my car. So my question and details. How much clearance should I have as a minimum between the front tires and the fender lips? The car is a 71 Duster, wearing 245/40/17's on 17x8's with 4.5" backspace. Right now there is no engine or trans, and no torsion bars or shocks. It is sitting on a couple of blocks under the k-frame to mock up ride height. No my wheels aren't optimal, but o like them and it is the only option for now. My suspension is all Hotchkis, I bought it long enough ago that even the t-bars are Hotchkis. I don't remember the diameter, somewhere between 1.04-1.12, just not certain. So now it is a delicate balancing game between looking good, and being useable. The compromise is just shy of two fingers clearance between the inner lip and the tire. About 1.75" clearance. How much clearance do some of you have with your fat tires and stuff bars? Thanks.:burnout:

 

[DartVadar]

I have more room in the rear with 255 tires on 15 inch rims. My car is pretty low though, especially on the front. I have 215/60 r15 tires on the front, when straight I can't even fit one finger between the tire and fender, it's perfectly tucked, slightly rolled inner fenders, but it can't get much lower than I have it. I'm going to say I have a quarter inch of clearance. So you should be fine lol.

 

[72bluNblu]

You sure you have your backspace number right?

Because your tires should stick out a 1/2" further than mine with those specs. I run 275/35/18's on 18x9's with 6.1" of backspace, and I have less than a 1/2" to the front fender.

17x8's with a 4.5" backspace and 245/45/17's would be outside of the front fenders on my car. Something's not right...

 

[71dusterdan]

Yes sir, 4.5" backspace on a 17x8. The wheels are Cragar Soft 8's. So how much clearance do you have 72blu? You were one of the guys I was hoping to hear from.

 

[72bluNblu]

Yes sir, 4.5" backspace on a 17x8. The wheels are Cragar Soft 8's. So how much clearance do you have 72blu? You were one of the guys I was hoping to hear from.

Yeah there's absolutely no way those wheels will fit unless you run your ride height like a 4x4. If you plug the specs into this wheel calculator, along with mine, you'll see that your wheel combo will be over a 1/2" further out than mine. That will put you into the fenders. You need a 5.25" backspace at least on a 17x8 to run a 245.

Check this out. This link should load up both of our tires, but if it doesn't you can enter mine as 18x9's with 275/35/18's and 27mm of offset (6.1" backspace). That's what my backspacing works out to if you're comparing my set up with the standard 73+ BBP disks.
http://www.rimsntires.com/specspro.jsp?item=Wheel-Tire%20size%20comparer&sw1=275&ar1=35&bd1=18&rw1=9.0&et1=27&text1=Sample%202:%20Honda%20Civic%20wheel&sw2=245&ar2=45&bd2=17&rw2=8.0&et2=0&text2=Sample%201:%20Hummer%20H2%20wheel

I only have about a 1/2" of clearance to my front fender. I know the picture shows about 5/8", but you can also see that's not the widest part of the tire. This is the minimum for clearance on the front unless you run the ride height a lot higher. Even at this height I occasionally get a "squeak" if I go through a driveway transition with the wheels turned (like pulling into a gas station with a sloped driveway). That showed up when I dropped the ride height the last 1/4", so above that there was never any contact. I haven't rolled the fender lips, which is my next project.

 

[71dusterdan]

I know you don't believe this, but your picture was exactly what I was looking for. I need to attach the front lower fender mount, and see if I have the bottom of the fender attached behind the wheel. Last night while I was jacking it up and trying to find a ride height that suited my eye, yet still functioned, I landed at about that same number, and it worked. Again I won't jump to conclusions, I will insure ive got the fender completely tied down. If I recall you are running a stiffer t-bar then what Hotchkis sold me a few years ago. Best I can figure mine are probably 1.03, so I may have more compression on my suspension than what you end up with. I swear if this works I am going to sport wood. If not I need to step down to a 235 or even a 225. In truth stretching either one of those on my 17x8, probably would not gain me much. Thanks for the pic.

 

[72bluNblu]

Don't forget this one.

The little bump in the lower fender brace is where I welded an extension onto it, making it 2" longer so that my tires would clear the corner of my fender. And of course you see where I cut the fender lip back, which was necessary even after I pushed the lower corner of the fender out.

Not sure what else there is to see, I'm not making up the math. Your tires will stick out an extra 1/2" from mine, which means they'll hit the fenders at the wheel arch unless your fenders sit high enough above the wheels that they don't touch with suspension travel. The lower corner is hard to say, because mine hit at around 80% of full steering input due to the width of my tires.

I've been wrong before, and I hope it works out for you. But if you're running the standard 73+ BBP disks and your fenders haven't been altered, those rims will not fit. You'd have to run 225's to get enough clearance.