Eric,

I’ve had 205/70-14s on the back of my wagon for eight years now, using 14×6 aluminum wheels with a slight negative offset (they are biased towards the outside). Obviously that tire is about an inch smaller in diameter than yours, but it’s the same section width. Scott Phillips has 215/60-15s on the stock 15″ wheels on his convertible…[Read more]

You do realize that if you replace the turbo motor, it is no longer a Jetfire, right?

3FM320825 is the VIN derivative.

3 = Oldsmobile Division
F = model year 1985
NOTE: the other tag indicates a 1984 model year. Are you sure this is an “F” and not an “E”? E would be correct for 1984.
M = Lansing assembly plant
320825 = last six digits from the VIN of the car it came from.

The stock tire size on 62 Jetfires and convertibles was 7.00 x 13, which was 25.8″ diameter. The fact that some vendor (who is not Oldsmobile) claims that 180/85-13 is the replacement tire doesn’t mean that it’s correct or even the same size as original.

205/55-16s are a Honda-sized 24.8″ in diameter.

I can tell you from first-hand information that 205/70-14 on 6″ wheels fit. I can also tell you first-hand that 215/60-15s on stock 15″ wheels fit. Both of those combos are about 25.25″ in diameter. Your 205/75-15s are about 27.1″ in diameter. Those would be a good choice for a 1968-72 Cutlass, but are waaaay too tall for the 61-63 cars.

TH200 is a lot smaller than the 700R4.

Kanter also sells new (Chinesium) wheel cylinders for $44 each or $146/set of four.

Oh, well, if it’s on the internet, then….

Look, I understand that tire section width will vary with wheel width for a given tire, but common sense should tell you that the exact amount of change will depend on the height of the sidewall and on the difference between the section width and the rim width. This can’t be a single number for ALL…[Read more]

Actually, I’m not sure where you got this 2/10″ per half inch of width formula. That will actually vary based on sidewall height.

Correct, and an extra 0.2″ of section width means all of 1/10″ wider on each side. I have waaaay more than 1/10″ of clearance to my fender lips.

What difference does that make? A 205 tire is still 205 MM wide (OK, give or take a little due to the rim width). My 205/70-14s are 25.3″ diameter and 8″ section width. 205/60-16s are 25.7″ in diameter and 8″ section width. My friend’s 215/60-15s are 25.2″ in diameter and just about 8.5″ wide, and they also fit fine.

Meaning what?

I’m running 14×6 aluminum slot mags with slight negative offset (maybe half an inch). Tires are 205/70-14.

Well, you definitely don’t have zero offset wheels. Mine has 205s on the back and I’ve had no issues for eight years now. My slot mags actually have some negative offset, which pushes the tires closer to the fender lip – still no problems. Mine are 14×6 wheels; overall tire diameter is 25.3″.

Are you asking about a Powermaster alternator that looks like a generator?

If all you care about is changing to a alternator, I also used the bracket from a 1963 215. Both a 12SI and a CS130 will fit this bracket with no mods. I swapped the pulley from the generator onto the CS130. Use the CS130 from a 1988-1990 Cadillac Fleetwood with the Olds…[Read more]

You can likely use brackets from an early Buick V6. The 215 is just a Buick V6 with two cylinders cut off. You likely can find Sanden brackets for that configuration.

Edit: Vintage Air sells Sanden brackets for a Buick 231 that can be adapted. You might need to modify or change the alternator/generator bracket,…[Read more]

I have 205s on my 62 with no issues. My friend has the 215s on his 62.

Well, I know first hand that 215/60-15s fit at all four corners on zero offset wheels. Your 225/50-16s are only 0.4″ wider and about a quarter inch SMALLER in diameter. The real question is, what is the width and offset of the wheels you are running, and do you have adapters or anything that pushes the wheels outward? Where do they rub?