challengergary
Well-Known Member
That looks awesome!
Anybody running 17" Cobra Bullit rims on a Duster
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Thanks! Pretty easy too once I found the right size caps and covers. That was the hard part, I have to say I have more than a few wheel caps that didn't fit laying around. Still worth it, the enkei caps for the rpf1's are $25 each, the ones I ended up with are $25 for the set of 4.
The fronts were pretty easy to make, I just cut the end off the pass through metal cap and then trimmed it to the right length with a pair of metal shears. A little JB Weld epoxy and some spray bomb paint and good to go!
Plus, since I have a few cars to go still I know I can have the wheels machines to a 73mm bore and still have a wheel cap solution. A 73 mm bore should clear the hub on the stock 11.75" rotors as well.
Been doing some wheel/tire mock up today with my friend's Mustang wheels. Tire is a Hancook Ventus with a 275/40/17. Leaf springs are Hotchkis' and are loaded to just about the height they're supposed to be (1" drop). Stock wheel tub. Uncut A body 8 3/4 rear end with 11.7" brakes with Mustang Calipers and a bbp swap. I also added 0.200" washers.
CultClassik
Well-Known Member
Hey MuuMuu101, what width are those wheels? 8 inch?
72BBSwinger
Well-Known Member
I believe they are 8 wide.
CultClassik
Well-Known Member
8 or 9 so we're in the ball park 
I've been trying to figure out if 275-45-17 are doable on a 17x9 in a stock wheel housing.
I've been trying to figure out if 275-45-17 are doable on a 17x9 in a stock wheel housing.
72BBSwinger
Well-Known Member
The 8" wheel makes the section width 1" narrower on the tire. It makes a difference. An 8 wide wheel will allow a 275 tire in an unmodified Dart rear wheelwell. A 9" will rub without work.
But so we're clear, a 275/40/17 isn't recommended for an 8" wide rim. Smallest recommended rim width for most 275/40/17's is 9". So if you put one on an 8" rim you're squeezing the sidewall quite a bit. If the point of the wider tires is better handling, cramming them on a rim that's too small will somewhat defeat that purpose. Better to run 255's and not get the additional sidewall motion.
Well, all I can tell you is that if they're 275/40/17's on 8" rims they don't work nearly as well as if they were on 17x9's. And yes, I run 275/40/17's on 17x9's.
In fact, if you talk to the autoX and road race folks, they typically prefer to run the smallest recommended tire on a given rim, not the largest. And a 275/40/17 is the widest tire recommended for a 17x9, unless you increase the sidewall height significantly. If you're just cruising it doesn't matter all that much, but when you start to push things the large tires on smaller rims tends to make the car feel more vague and less responsive. Not to mention you're really not getting the full advantage of the wider tire because you're squeezing it down to fit the rim. Might as well pay less for 255's and actually get to use the tire you're paying for.
The wheel pictured above is a 17 x 8" Mustang wheel w/ +30mm offset I've been using for a mock up in my '68 Dart. They barely hit the leaf springs on a stock A-body 8 3/4 housing even with the big bolt pattern swap and Dr Diff's disc brake kit. It's got a 275/40/17 on it and you can tell the sidewalls are bulged a bit. I measured it out physically and it was equivalent in width to a 255 series tire. I ended up purchasing 255/40/18's, they're just a touch taller, and I'm waiting for my 18 x 9" wheels. I'm going to use a +33mm offset for the front and +24mm offset for the rears with some sort of spacer (won't know how big of a spacer till I test fit it). As mentioned above, if you're going with an 8" wide wheel, I'd recommend sticking with a 245 or 255 series tire.
Well, as for the 255s they are 10 mm wider than the 245. I can tell you the 275 on an 8" rim is 1" wider than the 245. I'm sure it would be better on a 9" rim, but it does work and it doesn't look as wrong as you might think.
DionR
Well-Known Member
I tried to get some 275/40R17's mounted on some 17x8 rims and the guy couldn't get the sidewall to squeeze down enough to get it mounted. He was a friend that has some equipment, but not a shop, so maybe he just didn't try hard enough and gave up early.
I know it's been done, but it didn't work out for me. Just an FYI.
I know it's been done, but it didn't work out for me. Just an FYI.
Yeah I really don't care if it looks wrong or not, you are losing performance.
Some places won't even mount them up because they're out of the recommended range. And even though the section width might still be wider than a 255 the tread profile still isn't right. You'll probably also find any warranty provided will be voided, for both wear and damage.
Better to stay in the recommended range. Cramming a wider tire just to say you have a wider tire doesn't accomplish anything. I do run the minumum width rims on mine, which still isn't ideal for handling. But it does give you a little edge protection on your rims. And since my cars are primarily drivers I'm ok with that. But I wouldn't try to put a set of 40 series 275's on an 8" rim. My 275/35/18 fronts are on 18x9's, and my 295/35/18 rears are on 18x10's, and I wouldn't go with rims narrower than those for tires that size. Realistically I'd probably be better off with 255/40/18's and 285/40/18's.
Some places won't even mount them up because they're out of the recommended range. And even though the section width might still be wider than a 255 the tread profile still isn't right. You'll probably also find any warranty provided will be voided, for both wear and damage.
Better to stay in the recommended range. Cramming a wider tire just to say you have a wider tire doesn't accomplish anything. I do run the minumum width rims on mine, which still isn't ideal for handling. But it does give you a little edge protection on your rims. And since my cars are primarily drivers I'm ok with that. But I wouldn't try to put a set of 40 series 275's on an 8" rim. My 275/35/18 fronts are on 18x9's, and my 295/35/18 rears are on 18x10's, and I wouldn't go with rims narrower than those for tires that size. Realistically I'd probably be better off with 255/40/18's and 285/40/18's.
I physically measured the 275/40/17 tire on a 17 x 8" wheel and it's measurements were nearly the same as the listed size for a 255/35/18 tire on most tire manufacturer's websites. The wheel and tire is still sitting in my garage. To mount a tire on a non-recommended wheel size doesn't make sense from a performance and liability point of view. It's like the hella-flush import guys who stretch a 215/50/17 wheel on a 10" wide wheel. The only people who benefit from that are those who are competitive drifters and those cars aren't street legal.
As said before, get the recommended tire size for better performance and liability. It's honestly not going to look much different.
72BBSwinger
Well-Known Member
I used to have 335's on 18x10's. My car didn't know the difference when I switched to 18x12's. But I did get the rim width police off my back lol!
Man! I LOVE that car!
Ok I'm reading this thread, my question is, I've got a 64 val stock sbp with drums, can i just buy the 4 to 4.5 wheel adaptors, to run the bullitts, that should get me not only the clearance but the lug lenth also, ?
DirtySwiffer
Well-Known Member
hey if anyone could help me out on some info about the wheels and backspacing... and offset. im trying to figure this out and its all confusing me. 17x7 fronts on a 75 duster 0 offset and 4"backspace. where do you measure the backspace?the face of the hub in toward the spindle? the rears are 17x9 with 0 offset and 5"backspacing. i have the option of +12 offset on the 17x9 but that whell has a 5.47" backspace. how do you measure the offset to see where the wheels will end up? im not sure what exactly the offset even means. =offset sets the wheel out toward the fender more? or in toward the leafspring? any help would be great, thanks.
First off, what front suspension, rear axle, and brakes are you running as that can determine what your offset or backspacing is? Secondly, usually a 0 offset on A-bodies won't yield very wide tires. Most 17 x 7 wheels on the front with 0 offset that I've seen usually run a 215/45/17 or possibly a 225/45/17. The rear is a different story depending on the rear end or the car (as some A-bodies have different wheel wells) will determine as what tire you could run or if that 17 x 9 wheel will fit. I know I had to get the backspacing on my 18 x 9" wheel and 255/40/18 tires near perfect in my '68 Dart in order to get it centered in the wheel well and even then, some trimming will be required. Most people I know running a stock A-body rear will be able to run a 245/45/17 tire, since you have a '75 Duster, you may be able to stuff a little bit more under there.
My preferred method of choosing wheels is borrowing a wheel with a tire on it, throwing it on the car, and measuring to see what adjustments need to be made.
You can use this website to help you out: http://rimsntires.com/specspro.jsp
As far as backspacing goes, it measures from mounting surface of the wheel to the lip of the rim.
Backspace is measured from the backside of the wheel mounting surface to the lip of the rim. Offset is the distance of the mounting surface of the rim from the centerline of the width of the rim. Backspace is typically referenced on domestics like our Mopars, although newer cars and pretty much all imports use offset as the reference of choice.
So after digging through this thread for 2hrs, is this what needs to be don't to get the oem 17x8 with 5.72" BS to fit on my 72 Duster with BBP discs up front? can I turn the snout of the rotor hub down and run the 3/8" spacer instead of hogging out the center of the wheel? I'd prefer in not make so I can't put a center cap back in place.
Yes, you can turn the outer diameter of the rotor hub down a bit. And more than likely you'll need at least a 1/8" spacer anyway, because usually the 17x8's start interfering with the outer tie rod around 5.6" of backspace anyway. Only turn as much off the hubs as absolutely necessary, there's extra meat there but if you take out too much you'll weaken the hubs. Most of those OE rims have more space in the hub bore toward the inside of the rim, it's only the last little bit where the center cap is that necks down and interferes.
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