255/60/15 - stock 70-72 Dart

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rmchrgr

rmchrgr

Skate And Destroy
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OK, I'm looking for a definitive answer here. Went through a lot of old threads but could not find the exact answer I need. Sorry if this seems repetitive.

I am trying to plan out a wheel/tire combo for my '71 Dart. I am hoping to fit a 255/60/15 M/T Drag Radial in the stock wheel well with the springs in the stock location on my 8 3/4. A 235/60/15 should fit no problem since I have 245/60/14 on there right now with plenty of room. There do not seem to be 245/60/15 available in this particular tire. Yes, I can get the offset spring hangers but naturally this = more money since I'd need to buy the parts and don't have a welder. Not a big deal but I'd like to avoid it if possible.

So again -

1) 255/60/15 M/T Drag Radial in the stock wheel well with the springs in the stock location with no issues (rubbing etc.) - yes or no?

2) if yes, what is your backspace and what rim size are you using?

I don't have a floor jack at the moment so it's kinda difficult for me to measure things.

Thanks!
 
I have an 8.75 rear with the yukon axles that have a b body offset so my 15 x7 rims with 4.25 BS will only allow a 245-60-15. I am positive that with another 1/4 inch of BS I could fit a 255-60 in there (lots of measuring!). If you have a stock a body 8.75 it may work as it is. be sure that the answer your given has all your questions answered first! Unlike mine!!
 
no...i was using small brake axles drilled for big bolt pattern...as mentioned above if u have the big brakes u might need 4.5 backspace...now i moved the springs and run 275's :)
 
I was planning on upgrading to Moser large bolt pattern axles but was going to get 'em in standard a-body length. That's a big part of the budget right there, hence trying to make it work without buying more stuff.

I have the backing plates that came with the housing so 2" brakes it is. Good point there, never considered that the extra 1/2" would make a difference but makes sense - it does push the wheel out farther.

Based on the replies sounds like it will work using a 15" x 7" rim with 4.5" backspace. I'd be inclined to roll the dice and go without the offset hangers.

Anyone else care to chime in with definitive info?
 
My dart is all stock wheelwells and spring location. I run the CalTracs bars and mono leaf suspension set at 1" lower than stock height, Moser axels drilled to fit both 4"and4.5" bolt circles the stock 10" a-body drum brakes, with Weld Rodlite wheels 15x7 4.5 back spacing and 255-60-15 m/t dragradials. This wheel tire combo has never rubed even with four 200+ pound guys in the car.
 
19DART66 said:
My dart is all stock wheelwells and spring location. I run the CalTracs bars and mono leaf suspension set at 1" lower than stock height, Moser axels drilled to fit both 4"and4.5" bolt circles the stock 10" a-body drum brakes, with Weld Rodlite wheels 15x7 4.5 back spacing and 255-60-15 m/t dragradials. This wheel tire combo has never rubed even with four 200+ pound guys in the car.
Click to expand...

Hey, that's good news. Now the only remaining question is whether or not the '66 wheel wells are the same dimensions as the '71...

I actually planned to ask Calvert to arch the springs over stock height just to be sure. Maybe I don't have to.
 
there is more space under the 71 then 66 i have had 26x10.0x15 slicks under my 67 dart that should be the same as yours
 
test

P9150007.JPG
 
Hey, looks like you figured it out. Looking forward to seeing the pics.
 
thank you so much for that chris... :) greg, if u have any questions let me know...i think that size tire looks and fits great on that rim and body style...oh...these are split mono's for 2800 lbs a body at stock ride height... :)
 
Hey Doug, looks good. Thanks for your efforts on this, that's what I was looking for.

I went out and checked - I have a set of large bolt steelies - 15 x7 with 4.25" backspace. Guess I should be good to go.

I had the idea to go to a tire shop and see if they could mount a junk set of that size for me so I could check before buying. I probably don't really even need to based on the pics.

Now I gotta get my rear finished - I need axles and brake stuff, then a driveshaft.
 
Question,

Does anyone know if you had a custom offset made for a 70 Dart if a 275/60/15 will fit. Trying to mount widest tire possible without moving the springs or cutting the car up. I will order whatever offset will work from Wheel Vintiques stock looking Ralley wheels.

Trying to get as much rubber on the ground as possible.
 
Mad Dart said:
Question,

Does anyone know if you had a custom offset made for a 70 Dart if a 275/60/15 will fit. Trying to mount widest tire possible without moving the springs or cutting the car up. I will order whatever offset will work from Wheel Vintiques stock looking Ralley wheels.

Trying to get as much rubber on the ground as possible.
Click to expand...

Mad Dart,
I know of a 67 with the offset hangers/shackles, a stock length A-body rear, and Moser axles that has 275/60/15's on a custom 15x7 with 5" backspace. Don't have any pics, but from what I've seen of the car there is about 3/4" clearence between the lip and leaf spring...

DD
 
a 255 tire is a section width of 10". Thats the tire at the wides point, usually mid-sidewall to mid-sidewall. On a 7" wide rim, that's budging 1.5" past the rim of both side.

I'll run 215/70s to 235/60s on 7" wide, no bigger. By squeezing a 255 wide onto a 7" rim doesn't buy you clearance. An 8" wide rim is a much better bet for safety reasons. Go to the chart at the very bottom of this post.

FWIW:

A tire flexes like crazy! the lower the profile, the less flex. Look at the following video with a very low profile tire on a FWD race car. Look how that little sidewall still lets the tire flex all over the place. Now put a big'ole 60 series sidewall....on a marginally too narrow rim. You can see how you may peel the tire right off the rim. http://www.youtube.com/watch?v=UCCdxfBu66U

From the Yokahama website:
It is important to note that there are some differences between P-Metric and Metric approved rim width ranges (in general, Metric tires have a slightly narrower range). The TRA also has developed a measuring rim for each tire size that enables all manufacturers to measure their tires on the same size wheel. For 50-series tires and higher, the measuring rim width is 70% of the tire's section width rounded off to the nearest 0.5." For example, a P255/50VR16 tire, which has a design section width of 10.04", is measured on a 7" wide wheel.

Mid-Range Rim Widths
Provide a balance between handling capabilities and ride quality. The wheel's width influences handling and ride quality. Always choose a rim width within the range of the tire's acceptable rim width specification.

For tires that have an aspect ratio lower than a 50-series, the measuring rim is 85% of the tire's section design width. Therefore, a 255/40ZR17 tire with the same 10.04" section width would be measured on an 8.5" wide wheel. The measuring rims for Yokohama tires are listed with their dimensional data in this guide.


Now here is the recomended tire size / rim size chart. Note the 255/60 isn't given! A 235/60 is; this is why I like the 235 on the 7" wide rim. If you sort interpolate the chart.....255/60 on a 7" wide rim is too wide.

Below is a quick reference chart listing each Yokohama tire size and the acceptable rim widths for that size. Choosing a wheel near the middle of the range will give a balance between ride quality and handling. A wider wheel will improve handling at the expense of ride quality, while a narrower wheel will improve ride quality at the expense of handling. Consider these compromises when selecting wheels.

Metric Rim Widths
Aspect Ratio Metric Size Designations Approved Rim Width Ranges

--------------------------------------------------------------------------------

35 Series 275/35R17 9.0-10.5
335/35R17 11.0-13.0
345/35R15 11.0-13.5

40 Series 285/40R15 11.0-13.5
215/40R15 7.0-8.5
245/40R17 8.0-9.5
255/40R17 8.5-10.0
265/40R17 8.5-10.0
235/40R18 8.0-9.5

45 Series 195/45/R15 6.5-7.5
215/45R15 7.0-8.5
255/45R15 8.5-10.0
205/45R16 7.0
225/45R16 7.5-9.0
245/45R16 8.0-9.5
215/45R17 7.0-8.5
235/45R17 8.0-9.5
255/45R17 8.5-10.5

50 Series 175/50R13 5.0-6.0
195/50R14 5.5-7.0
205/50R15 5.5-7.5
215/50R15 6.0-7.5
225/50R15 6.0-8.0
195/50R16 5.5-7.0
205/50R16 5.5-7.5
225/50R16 6.0-8.0
235/50R16 6.5-8.5
215/50R17 6.5-7.5

55 Series 205/55R14 5.5-7.5
185/55R15 6.0-6.5
195/55R15 5.5-7.0
205/55R15 5.5-7.5
205/55R16 5.5-7.5
225/55R16 6.0-8.0

Aspect Ratio Metric Size Designations Approved Rim Width Ranges

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60 Series 185/60R13 5.0-6.5
205/60R13 5.5-7.5
185/60R14 5.0-6.5
195/60R14 5.5-7.0
205/60R14
195/60R15 5.5-7.0
205/60R15 5.5-7.5
215/60R15 6.0-7.5
225/60R15 6.0-8.0
235/60R15 6.5-8.5

65 Series 185/65R15 5.0-6.5
195/65R15 5.5-7.0
205/65R15 5.5-7.5
215/65R15 6.0-7.5

70 Series 165/70R10 4.5-5.5
175/70R12 5.0-6.0
175/70R13 5.0-6.0
205/45R16 7.0
185/70R13 5.0-6.5
185/70R14 5.0-6.5
195/70R15 5.5-7.0
205/70R14 5.5-7.5
185/70R15 5.0-6.5
205/70R15 5.5-7.5
215/70R15 6.0-7.5

82 Series 155R12 4.0-5.0
155R13 4.0-5.5
165R13 4.0-5.5
175R14 4.5-6.0
185R14 4.5-6.0
165R15 4.0-5.5




P-Metric Rim Widths
Aspect Ratio Metric Size Designations Approved Rim Width Ranges

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75 Series P205/75R15 5.5-7.5
P215/75R15 5.5-7.5
P225/75R15 6.0-8.0
P235/75R15 6.0-8.0

80 Series P155/80R13 4.5-5.5
P165/80R13 4.5-6.0
P175/80R13 4.5-6.0
P185/80R13 5.0-6.5

Aspect Ratio Metric Size Designations Approved Rim Width Ranges

--------------------------------------------------------------------------------

35 Series P315/35R17 10.0-12.0

40 Series P275/40R17 8.5-10.0

50 Series P215/50R13 5.5-8.5
P235/50R13 6.0-9.0
P245/50R14 6.5-9.0
P225/50R15 6.0-8.0
P295/50R15 7.5-11.0
P225/50R16 6.0-8.0
P245/50R16 6.5-9.5
 
19DART66 said:
My dart is all stock wheelwells and spring location. I run the CalTracs bars and mono leaf suspension set at 1" lower than stock height, Moser axels drilled to fit both 4"and4.5" bolt circles the stock 10" a-body drum brakes, with Weld Rodlite wheels 15x7 4.5 back spacing and 255-60-15 m/t dragradials. This wheel tire combo has never rubed even with four 200+ pound guys in the car.
Click to expand...

Could you post some pictures of your clearance. Also do you think you could squeeze a 8" Rim into the equation using the same offset or with little change?
 
Mad Dart, On my 66 I have about a 1/2 inch clearence between the sidewall and the leafspring and 1 inch of clearence to the lip on the quarter. The problem with going to a 8 inch rim with the same 4.5 back space is not only do you move the rim out 1 inch you move the center of the tire out to. With a 7 inch rim the tire is centered in the wheelwell on an 8 it offsets it to the out side. A good freind of mine has a 69 340 Swinger, he has 275-60-15 m&h drag radials on 7 inch rims, they will scuff up in side the wheelwell on big bumps and dips with some one in the back seat, he had 235-60-15 bfg on 8 inch before (with same back spacing) rubed the side walls off on the lip of the quarter on all turns,bumps ,and dips. P.S. Mickey Thompsons section width on a 255-60 is measured on a 7 inch rim.
 
19DART66 said:
Mad Dart, On my 66 I have about a 1/2 inch clearence between the sidewall and the leafspring and 1 inch of clearence to the lip on the quarter. The problem with going to a 8 inch rim with the same 4.5 back space is not only do you move the rim out 1 inch you move the center of the tire out to. With a 7 inch rim the tire is centered in the wheelwell on an 8 it offsets it to the out side. A good freind of mine has a 69 340 Swinger, he has 275-60-15 m&h drag radials on 7 inch rims, they will scuff up in side the wheelwell on big bumps and dips with some one in the back seat, he had 235-60-15 bfg on 8 inch before (with same back spacing) rubed the side walls off on the lip of the quarter on all turns,bumps ,and dips. P.S. Mickey Thompsons section width on a 255-60 is measured on a 7 inch rim.
Click to expand...

Here is the link for the M/T Street ET Radials.......it says the 255-60-15 was measured on a 7.5" Rim.

http://www.mickeythompsontires.com/strip.php?item=ETStreetRadial

But that is ok, I really appreciate you taking time to help me with the correct tire choice and backspacing. I have 255/60/15's saved on my wish list at Jegs and Summit. If I could find a 7.5" Rim and use the 4.5 back spacing it seems that it would fit about right? Maybe a little tight. So you have about 9" of tread on the ground right?
 
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