Mast Sheave Replacement

[SF Bay Dude]

I want to replace my main halyard sheaves since the mast is down. Would be nice to have less friction for raising and lowering the main. The sheaves are 5" diameter by 3/4" wide with a 5/8 diameter center pin. I am having a hard time finding those direct replacements. I am wondering a couple of things.

1. First off, what would be a safe working load? My main is somewhere around 550 sq ft and the mast is about 50'. I am running 12mm Endurabraid for my new halyards. Halyard is tensioned at the mast via winch and then stopped off with a clutch. Probably not an issue for the sheaves I am looking at, but just thought I would ask.

2. Should I try and find a similar diameter sheave, or is going a little bit smaller ok? The bigger ones are quite pricey.

3. The center pin has me stumped. I feel like a few of the 4" and smaller sheaves available by Harken and other brands would fit the bill, but the center pins are usually offered in 1/2", and I need 5/8". I don't want that extra slop in the sheave. I could go bigger, but then the price to replace the sheaves goes WAY up. And I would have to drill a bit bigger hole - 7/8" - for the pins, and buy new pins.

4. Or do I buy a sheave with a 1/2" diameter axle pin and get new pins? But would those seat and ride properly on the larger diameter holes in my mast? I am thinking not?

5. Or do I just keep my old sheaves - which appear to be aluminum and in good shape - and just throw some lube on them and call it a day!

Any thoughts?

Thanks!

[wholybee]

https://www.zephyrwerks.com/

They will make exactly what you want, for a reasonable price and they ship very quickly.

[Allied39]

Have you checked grainger?. Do not limit yourself to marine, it's an expensive word that one.

[psk125]

Though sheaves can slow things up, a good bit of the friction in raising & lowering the main comes from the sail luff groove or tracks, not the sheaves. Especially if the sail is slow coming down, it's not the sheave causing the problem. Test them to see if they spin easily or not. If they appear to be in good shape it would make more sense to simply give them a shot of WD40 or McLube or something. Then clean your luff groove or track and lube that up too before spending anything on new hardware.