Conversion to disc brakes

[marcel]

Having installed BCCP (Ben’s) disc brakes setup on the front of my 1962 Olds F85 Cutlass.
Need help with choosing the correct fit wheels & tires ? Maybe GW steel wheels 15X7 or 15X6 , not sure of the offset_____.
My original (4 lug)13 in. wheel/tires the overall diameter was 24 inches. (P175/80R13)
(I did a comparison with the 15 in. wheels on my current car and the diameter was the same as 185/65R15)

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[62cutlassconvert]

What master cylinder did it come with?

I did the 4 lug conversion and am running 15x 6 with a 35/8” backspace. 205 65 15H tire. Wheel Vintique Smoothies. Steel. Lots of alloy wheels available in 5 lug.

Car is dropped with 1” lower springs

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[joe_padavano]

I can tell you from personal experience that 215/60-15s on wheels with zero offset fit just fine on stock brakes. I have no idea if or how much that conversion pushes the wheel mounting surfaces outboard.

[62cutlassconvert]

Uses the stock spindle for the 4 lug so no change.

[joe_padavano]

The spindle has nothing to do with where the wheel mounting surface on the new rotors ends up relative to where it was with the stock drums. That’s entirely a function of the design of the rotor.

[62cutlassconvert]

Oops, meant to say stock spindle and hubs.
Yep, I would imagine the thickness of the rotor hat would influence the wheel placement further to spindle and hub.

[joe_padavano]

How do you drill the stock hubs for five lugs? There are only four thickened areas on the backside for the studs.

[62cutlassconvert]

BCCP doesn’t. He uses a different hub.

I dont know this for sure but i believe i remember the Tempest hub in front is a five lug? There is another one or two as well I believe. Couldn’t confirm which ones. Then you go for new axles in the rear I believe. BCCP can supply or Moser will make them. Not cheap.

Also, there are two hub styles, one that has the high and low areas and one that is all high(thick) areas. I guess that could be filled and redrilled. I was told by a machine ahop they do not recommend filling and drilling out the rear axle. I was told the process weakens the flange, better to get new axles which are easily available.

[marcel]

Thanks for the feedback, I have already installed the 5 lug spindle front & new 5 lug rear axle. I though I was going with 15X6 OE Style/ 5×4 3/4 bolt / 3.75″ backspace & American Classic 165R15, but the (rim) 15x 6 with a 3 5/8” backspace Wheel Vintique Smoothies looks like it might be an option. Will the Smoothies clear the disc brake?

[joe_padavano]

So back to my original point. If the spindle and hub are changed, there’s no way to know what offset works without measuring the specific car with the specific disc brake conversion installed.

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