275's are on!

[vinb]

I had 295/50/15's on the rear with a 8 1/2" wheel.
Fit OK , no problems hitting the springs...
I took them off because they were too short 83" round,
went to a 275/60/15 89" round..

[74chall]

Ah, i forgot to add in a 17" rim size. I have 11.50 hoosiers back there now on 15" rims

[PlumCrazyChris]

Read this entire thread and you'll know all the possibilities.

http://www.cuda-challenger.com/cc/index.php?topic=19470.0

But I think the largest, at least the most common "Biggest tires" (with stock 4.5" backspacing) are 275/60/15s on the back, (although some say they can get 295/60/15s on there), and 245/60/15s on the front. 

It does change some when you go with different size rims.  But basically just use this handy "tire size comparer" ,shown below, and see what fits within the confines of the above named "standard" big tires. 

On 17" rims, it looks to me like you can get 275/40/17s on both the front and back.  You may be able to get bigger on the back, but you'd have to compare to the 60/15 dimensions to be sure. 

http://www.bigcustomwheels.com/rt_specs.jsp

Although personally I wouldn't go with anything shorter then a 45 or the tires will look way to small for the wheelwells.  You'll have to lower your car a lot to get it to look right.

Move your springs in a little and you can get a Lot more tire on the rear.   Dr. Diffs bolt-on, 1.5", spring relocation kit will allow you to get at least a 315 in the back with the correct backspacing.  http://www.doctordiff.com/

Good luck,
Chris

[Road_Runner]

Move your springs in a little and you can get a Lot more tire on the rear.   Dr. Diffs bolt-on, 1.5", spring relocation kit will allow you to get at least a 315 in the back with the correct backspacing.  http://www.doctordiff.com/

I went to the doctordiff site, but the pictures wouldn't come up.  Plus I only saw  a 1" E-body relocation kit listed but you say yours is 1 1/2", are these the same kits?  Plus, you say they're bolt on, but do you have to move the spring perches on the rear casing itself?  If not, how does it work?  Lots of great info here.

Thanks, Jim

[miketyler]

Cass may advertise them as 1 1/4" relocation kit but you can get 1 1/2" movement if you push it. All is bolt on but the perches do have to be moved in. 

[SBDave]

I've been reading a lot about having the proper rim width for a tire.  What are your thoughts on running 275/40-17 on a 17x9 rim with 4.5" backspacing on the front and back on a stock 1973 Barracuda?  I realize it specifically depends on the car but would it even be close to fitting?  I want to run the same size wheel/tire combo front and back.  Sounds like the front is the limiting factor.  Would that first combo rub on the front when turning?  My next idea is a 255/50-17 or 255/45-17 all the way around on 17x8 w/4.5" backspacing. 

I'll probably post this in the Tire Combo thread some time as well.

thanks,
Dave

...my car is setup with the XV level 1 suspension kit and has Mancini lowering leaf spring hangers (might even use 1" blocks to bring the rear down more)

[vinb]

Tommyg,
Please make some room in your inbox , trying to send you a pm..

ThanksVin...

[tommyg29]

just cleared them all out

[Travis72]

Dave,

Be aware that each car is a little different, however on my Cuda (with an AlterKation front suspension) 255/45/17s on 17x8 rims did not clear the front edge of the fenders.  With more backspacing they might have cleared, but it would have been really close. 

Anyway, on your car they might fit fine, but just make sure you measure first and check the clearance at the front edge of the fender lip.

Travis
72 Cuda

[autoxcuda]

I've been reading a lot about having the proper rim width for a tire.  What are your thoughts on running 275/40-17 on a 17x9 rim with 4.5" backspacing on the front and back on a stock 1973 Barracuda?  I realize it specifically depends on the car but would it even be close to fitting?  I want to run the same size wheel/tire combo front and back.  Sounds like the front is the limiting factor.  Would that first combo rub on the front when turning?  My next idea is a 255/50-17 or 255/45-17 all the way around on 17x8 w/4.5" backspacing. 

I'll probably post this in the Tire Combo thread some time as well.

thanks,
Dave

...my car is setup with the XV level 1 suspension kit and has Mancini lowering leaf spring hangers (might even use 1" blocks to bring the rear down more)

No way 275/40/17 tire on 17x9 rim with 4.5" backspacing on the front is going to fit. You need to run 5.3" or so backspacing. MikeTyler runs 275/40/17's on his Cuda. Do what he did.

The amount of backspacing will be limited to the inside profile of the rim and the interference point should be the outer tie rod end. Also the wide style RMS tubular upper arms will hit at full turning lock with 5.3" high backspace rims. Use factory or straight legged upper A-arms if you plan on over 5" backspace front rims. Just found that out recently from someone on another list.

Here's picture of Mike Tyler's Cuda's 275/40/17's. Which front tire do you think has more grip?

[SBDave]

Sorry, I misread what backspacing Mike was using on his car.  Sounds like my best shot is something between 4.75 and 5.25" backspacing.  I need to start talking to some local wheel and tire shops to see what they say.  I can't really decide if I wan't to modify the front fender lips for clearance yet.

Great setup Mike!  Thanks for posting the pictures and info.
-Dave

[autoxcuda]

Sorry, I misread what backspacing Mike was using on his car.  Sounds like my best shot is something between 4.75 and 5.25" backspacing.  I need to start talking to some local wheel and tire shops to see what they say.  I can't really decide if I wan't to modify the front fender lips for clearance yet.

Great setup Mike!  Thanks for posting the pictures and info.
-Dave

For 275/40/17 up front, I think it's going to have to be at least 5" backspacing if you are running 9" wide rims. Hopefully Mike Tyler will chime in.

Just thinking this through please correct me if I'm wrong...Comparing to the the 275/40/17 on 17x8 with 4.75 backspace Mike runs.... If you run a 9" wide rim, also with 4.75" backspacing,  the outer tire edge should be moved out 1/2". ??

Darn wheel calculator link is broken. 

[PlumCrazyChris]

This link seems to be working now, but it wasn't a minute ago.  If it won't work, take it back a level to the parent website and then go to "Size Guide"

http://www.bigcustomwheels.com/rt_specs.jsp