What's a reasonable tire size for a 1965 Special wagon on 15"x7" wheels?

[elagache]

Dear those who live, breathe, and dream, 1965 Buicks . . . .

I need to decide on some larger tires for my assertive 1965 Buick Special wagon with a big-block Buick engine.  The engine is putting put over 500 foot•pounds of torque and almost 500 horsepower, but it is extremely easy to control.  Since I don't intend to use that power at all, my feeling is that I simply need conservative tires that will cope with rare instances of getting caught in the rain, but nonetheless are only used for normal daily-driving.  I've been driving her with her seriously undersized P205/70R-14 Coker tires and she handles just fine for my needs (at least in dry weather.)

I have already bought a set of 4 57 series Buick Rallye wheels by Wheel Vintiques:

http://www.wheelvintiques.com/wheels/muscle/buick-rallye.html

I bought the 15" x 7" wheels which gives me 4" of back spacing.

I would like to buy some Diamond back III tires that are a remanufactured version of the B F Goodrich Radial T/A.  The Diamond back process allows me to get a traditional 1960s white-wall tire that is no longer available from B F Goodrich.  They can be made in a wide variety of sizes.  Here is the table from the Diamond back website:

http://www.dbtires.com/store/shopbrand.cfm?brand=61

A few years back I started a thread on V-8 Buick and got suggestions like 235/60-15 for the front, and if desired, something larger like 255/60-15 for the back.  What sort of tire and rim combinations are you guys using?   My original goal in upgrading my wagon was to be able to tow a modest travel trailer.  At the moment though, that project looks many years away, so I might simply settle for 4 tires of the same size for the interim.

Thanks in advance for advice born of years of experience! 

Sincerely, Edouard

P.S. I'm already aware of the fact that I'll have to recalibrate the speedometer as a result of the change in tire size.  I'm already committed to this because of the switch from the TH350 to the 200-4R transmission.  I really need to settle down on the tire size and then the appropriate rear end ratio so that I can indeed get the speedometer displaying accurately once more.

[sportwagon400]

on my 65 Sporty I now run 255/50/16 on the rear on 16X8 rally's with 5 1/2" of back spacing but I also use 69 A body diff so 1/2" wider each side   to run a 255/60/15 you should have 5" back spacing minimum or it will rub

I have put many different combinations on the old girl but these I think look the meanest and most stealth

[sportwagon400]

I have run many styles of rims on this car and always try and fit biggest tire

245/60/15 fit ok on my stock 15X7 rally's but worked better on my 15X8 with 5" back spacing

my torque thrust rims have 235/60/16 on 15X8 with 5 1/4 bs could easily go 255/50/16

[GS66]

They all look good on your car.

[Loren At 65GS]

They all look good on your car.

X2 
Good thing you showed up Ken. Now Edouard won't feel lonely.  LOL

Maybe there will be a wagon in my garage someday.  I've always liked them.

  Loren

[35chevcoupe]

The wider the better , and I like to share them with the neighbor hood  . 

[GS66]

Nice John! I agree, you don't want them dry rotting from old age.

[elagache]

Dear Ken, Jim, Loren, and mid-60s longroof fans,

Shuck Ken I'm overwhelmed!! . . .

Should I ask about the specs on that 350, or . . . . do I not want to know!

on my 65 Sporty I now run 255/50/16 on the rear on 16X8 rally's with 5 1/2" of back spacing but I also use 69 A body diff so 1/2" wider each side   to run a 255/60/15 you should have 5" back spacing minimum or it will rub

I have put many different combinations on the old girl but these I think look the meanest and most stealth

Still, I'm guessing that you are in the business of "killing" the competition!

I have more modest goals in mind, but if I ever get around to pulling around that vintage Airstream trailer of my dreams, I would need plenty of traction on the rear tires.  Do you have any idea of the potential rubbing problem on the rears?  Are the 255/60/15 rubbing on the rear or the front?  To get away with what I'm imagining down the road having larger tires on the rear than the front is probably unavoidable.

Thanks for the neat pictures - that's one sharp wagon!

Cheers, Edouard 

[WkillGS]

I run 255/60-15's (rear) and 235/60-15's (front) on my 66's.
Wheels are 15 x7 Buick rallys that have 4-3/8" backspacing. Note that these wheels measure 8" wide outside edge to outside edge. Back space is also measured to the outside edge. 'frontspacing' would measure 3-5/8" on these. 4-3/8" + 3-5/8" = 8".
It is a 7" wide wheel when measured between the mounting lips.

255's are a tight fit on the rear of a '66. The '65's supposedly have a little more room at the fender lip.
255's will rub on the front of my '66, that's why i run 235's.

Instead of 60 series tires, consider 70 series for more fender clearance. You can use the same size at all 4 corners.
I don't think traction will be a problem with the added weight of a trailer pushing those tires into the ground.

[GS66]

I have 70's on all 4 corners on one of the 66's. I believe they are 215 or 225-15 on the front and one or two sizes bigger in the rear, but I'm using 6" Cragars.

[sportwagon400]

Shuck Ken I'm overwhelmed!! . . .

Should I ask about the specs on that 350, or . . . . do I not want to know!

I have put many different combinations on the old girl but these I think look the meanest and most stealth[/quote]

Still, I'm guessing that you are in the business of "killing" the competition!

I have more modest goals in mind, but if I ever get around to pulling around that vintage Airstream trailer of my dreams, I would need plenty of traction on the rear tires.  Do you have any idea of the potential rubbing problem on the rears?  Are the 255/60/15 rubbing on the rear or the front?  To get away with what I'm imagining down the road having larger tires on the rear than the front is probably unavoidable.

Thanks for the neat pictures - that's one sharp wagon!

Cheers, Edouard 
[/quote]

Thanks for the complement on the sporty the 255/60/15 will not fit the front 235/60/15 are tight if you want a 26" tire run a 215/65/15 works perfect on stock 15" rims back spacing is the key!!! I have had rims custom made at times as well I have had centers moved to get the look I, like with the largest tire. I also like mine lower than stock so I have tried many combinations as well
all rims are measured inside the bead area never outside back spacing is measured from the inner mounting surface to the outer rear lips, 99% of after market rims have less back spacing for the wide look   sadly our 64-65 cars don't have the wheel well space to fit small back spacing, I have run 15X9 1/4 with 6" back spacing ( custom offset ) using a 68-72 rear diff with 255/60/15 rubber and it was friggin close

My 350 is pretty mild 300 hp QJET 2004r od 3.31 posi diff it really needs 3.73 gears with the 2004r. I will be setting it up to pull a trailer soon but ill be using my TH350 with a gear vendors OD unit and the 3.31 diff gives me a final drive of 2.5 perfect for the Buick motors   the current set up with the 200r AND 3.31 gives ne a 2.2 final drive great for cruising at 85-90 but the local cops frown on that hahaha I have put over 40,000 on the sporty and I know what works and what is hype at least for me anyway

good luck with yours look awesome as well   I am looking for a 65 Special wagon  my 65 F85 will have to do until I find a Buick   and of course a 65 GS HT would be a perfect addition to my Buick fleet

[elagache]

Dear Walt, Jim, Ken, and mid-60s Buick fans,

Thanks for all the helpful advice! 

Instead of 60 series tires, consider 70 series for more fender clearance. You can use the same size at all 4 corners.
I don't think traction will be a problem with the added weight of a trailer pushing those tires into the ground.

Okay, that's a good point.  I forgot to consider the tongue weight even if a load equalizing hitch will absolutely necessary.

I have 70's on all 4 corners on one of the 66's. I believe they are 215 or 225-15 on the front and one or two sizes bigger in the rear, but I'm using 6" Cragars.

if you want a 26" tire run a 215/65/15 works perfect on stock 15" rims

Okay, so what would be the consensus? 215/70/15 or 215/65/15?  Both are available.

My 350 is pretty mild 300 hp QJET 2004r od 3.31 posi diff it really needs 3.73 gears with the 2004r. I will be setting it up to pull a trailer soon but ill be using my TH350 with a gear vendors OD unit and the 3.31 diff gives me a final drive of 2.5 perfect for the Buick motors   the current set up with the 200r AND 3.31 gives ne a 2.2 final drive great for cruising at 85-90 but the local cops frown on that hahaha I have put over 40,000 on the sporty and I know what works and what is hype at least for me anyway.

Sounds like a nice combo!  What sort of towing did you have in mind?

good luck with yours look awesome as well   I am looking for a 65 Special wagon  my 65 F85 will have to do until I find a Buick   and of course a 65 GS HT would be a perfect addition to my Buick fleet

Well, 1965 Special wagons are out there.  You just can't have mine!    Best of luck in expanding your Buick motorpool!

Cheers, Edouard 

[sportwagon400]

my wife wants a vintage trailer so she can come to more events, so I am on the hunt for something that's cool  and old ( like me I guess hahaha )  I may have to go big block if I pick some thing to large but that's no problem I have several ready to go in the sporty including my old stage 1 that pushed my 4800lb 69 sporty to high 12's hahaha

ken

[sportwagon400]

as for 65's or 70's I prefer 215/65/15 as the 70 series tire to get any width you are getting too tall in my opinion  the 215/65/15 is 26" and the 235/60/15 is also 26" tall
245/60/15 is 26.5 and the 255/60/15 is 27" tall   I like them to be as wide as possible   too  much sidewall high also makes then lean too much in corners and all of my cars are built to drive at speed around corners too :):)

[dsags]

Another vote for the 215/65's.