Rear tire size needed for 340 stroker?

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Richard McLaughlin

Richard McLaughlin

1974 Duster 340
Joined
Oct 10, 2016
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Location
New Brunswick
Hello,

So I have a 73 340 in my Duster.
I plan on upgrading the power within a few years (stroker etc)
I would like to get new rims and tires sooner than that.
If I was to upgrade with a 416 stroker in the future, what rear tire size would I need to acomadate that power? Would 275 60 15 be big enough? Or would I need to do some mods? Min tub etc?

Thanks!
Richard
 
Use, gearing, and suspension set up matter greatly in this conversation... But yea, 275 sounds reasonable, especially with a good compound.
 
you need to figure out what torsion bars, springs, and shocks you have.

are you concerned with cornering traction more than straight line???

correctly spaced wheels and maybe offset spring hangers will get you 275 rears, which will provide great street traction with a good tire. you will also need to increase your front tire size for handling and braking during increased speeds. spring rates and shock design will affect traction significantly but differently during different types of driving.

There are more educated gurus on this forum than me, but more tire means more traction, and with around 500rwhp it is hard to have too wide of a tire.
 
Trying to figure out what tire size to use is just one of many components that need to be figured out when building/setting up a car. I'm not saying that you're putting the cart before the horse but all of the sub-assemblies should be taken into consideration before making changes/purchases (to eliminate wasting time/money). Build it all on paper.

Btw: A 275/60/15 should easily fit in a Duster rear well even on a 15x8 rim with the right back spacing. Just remember to measure both sides since Ma wasn't known for perfectly centering her rearend assemblies. As 72Val said, if there was a minor clearance issue, you could sue the offset hanger/shacke kit and get an extra .8".
 
GTXperience said:
Trying to figure out what tire size to use is just one of many components that need to be figured out when building/setting up a car. I'm not saying that you're putting the cart before the horse but all of the sub-assemblies should be taken into consideration before making changes/purchases (to eliminate wasting time/money). Build it all on paper.

Btw: A 275/60/15 should easily fit in a Duster rear well even on a 15x8 rim with the right back spacing. Just remember to measure both sides since Ma wasn't known for perfectly centering her rearend assemblies. As 72Val said, if there was a minor clearance issue, you could sue the offset hanger/shacke kit and get an extra .8".
Click to expand...

275/60/15 ON 7 INCH RIMS WITH OFFSET SHACKLE KITS FIT PERFECT.
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No. If that's the route you want to go, you need the whole kit with the offset front hangers, and new spring perches for the rearend housing as well. Or you can just drill four new holes for the front hanger inward 1/2" and reuse the stock front hanger, do something similar in the back and just buy new spring perches. Do you have welding capabilities? Because, you'll need to in order to move the perches on the rearend housing inward.
 
I would move the springs the 1/2" to make room for a 275/60 tire. It's not required though in a Duster. Your backspacing needs to be spot on though. Do you have welding capabilities?
 
A 275/60/15 tire on a 8 inch wheel with 41/2 inch back spacing will fit. Doesn't require any cutting or welding or spring relocation kit.
 
I run 275/60R15 Cooper Cobras on 15x8 Cragers with 4.25" backspace and only have about 3/8" clearance from tire to leaf spring. But my rears don't rub one bit.
I see people saying 4.5 backspace fits all the time, but I don't think it would on my car...not without spacers.
Espo 1" over stock height springs, stock abody 8-3/4.

Now my fronts are 14x6 with 4.00 bs and 225/70R14 and they DO rub on the lower rear corner of the fenders if the wheels are turned on any kind of bump like a driveway. So for fronts I would go maybe 215/60...you might get away with 225/60. Not sure. I will find out what I'm switching to in Febuary.


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cuda20 said:
A 275/60/15 tire on a 8 inch wheel with 41/2 inch back spacing will fit. Doesn't require any cutting or welding or spring relocation kit.
Click to expand...
A 275/60/15 on a 7" rally wheel with 4 1/4" back spacing hit the springs on my 73 Duster with stock 8 1/4 rear end. It way fit with the 8 3/4 rear end but would hit on mine without the relocation kit. If you use a wheel with 4" or less back spacing you may be able to pull it off but then the rear wheels stick out kind of far for my liking. It`s all personal preferance i guess.
 
Here are my suggestions to you.
I have a Hellwig no.5905 1 1/8'' solid sway bar on the front of my Dart Sport(cousin to the Duster and brother to the Demon...same cars) and love it. It prevents my headers from scrapping on anything, unlike before and many other benefits besides including cornering. I even priced them for you and through Amazon.ca is the cheapest way I found. $270.56 CDN + free shipping. For starters that is the first thing I would get. If you get it from the states there is shipping, duty and exchange which adds up to much more than that unless you are able to pick it up, then all you add is fuel and exchange which still adds up to a higher total.

Then there was the matter of tires:
For front tires I would go with 255/60R15 for the front, if it fits, $150.00 to $155 CDN( that big a tire will be hard to steer) . The biggest 15'' that fits on my Sport is about 205-215/65R15 with a stock front suspension. I run 7'' wheels in front.
And 275/60R15 for the rear $160.00 range...first choice BF Goodrich T/A 2nd choice Cooper Cobra. Both have raised white letters. The 255 is 27'' tall and the 275 is 28'' tall. With big & wide front tires you will likely have to raise your front suspension and maybe require other mods. I have 8'' wheels in back with 255/60r15. If you run 275s in back your gears will have to be in the range of 380-400 to 1.
 
Last edited:
GTXperience said:
Btw: A 275/60/15 should easily fit in a Duster rear well even on a 15x8 rim with the right back spacing. Just remember to measure both sides since Ma wasn't known for perfectly centering her rearend assemblies. As 72Val said, if there was a minor clearance issue, you could sue the offset hanger/shacke kit and get an extra .8".
Click to expand...

I'm replying to my own post to reiterate that every A-body (and every model ... in this case - Dusters) are NOT all going to have the same clearances in the rear. As mentioned above, Ma wasn't known for perfectly centering her rearend assemblies. Some people are going to be able to get away with equal offsets and wheel widh that will allow a 275/60/15 tire without any mods. Some will not because their rearends are not refectory centered. Clearances and wheel/tire combos should be figured out on an individual basis. Of course, this is when you're trying to max out a wheel/tire combo. Also, take into consideration the design of different 275/60/15 tires from different mnfrs. Sometimes there are slight differences in sidewall design and flex.

On my 69 Barracuda, I choose to add the offset kit so I could max out my wheel/tire combo. Because I was moving the perches, anyways, I corrected the centering of my rearend by 1/2". The offset moved the springs in .8" and allowed me to run a BFG 275/60-15 on a 15x8 Ramcharger steelie. To maximize the space, I cut the center out of the wheel and moved it .75". The fit/look is right on the money.
 
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