On my SS/FG a .75 chain gauge now fits in, is it time to replace the chain? The 1.0 side of the gauge won't go in yet.

I'm assuming I've got a 1/8" chain, will the tool I use to break a 10 speed Shimano chain work on the 1/8" as well?

On my road bike, I use a KMC with their master link. Is it recommended to run a master link on a SS/FG as well?

Any recommendations on what brand chain to buy?

Thanks!

Get yourself a good steel rule and measure the chain with that. Chain checkers are notoriously inaccurate.

+1, any 12 inch rule (doesn't have to be fancy or precise) will be an accurate chain wear checking gauge. However the replacement guidelines apply only to chains used with derailleurs or spring tension arms. On SS or IGH bikes with a simple chain loop, the chain doesn't have any spring loaded slack and therefore cannot skip until the sprocket teeth are tiny nubs. Feel free to run your chain until it's stretched about 3%, which will take quite a long time.

To prevent excess wear, be sure the lower loop has enough slack to sag slightly compared to a straight edge laced above it.

You may or may not have a 1/8" chain. Some people set up FG/SS with 3/32" drivetrains.

I use a KMC master link on all my chains so I can easily remove them for maintenance.

As far as chains go, I typically use a KMC 710SL (just because they're reasonably priced and work well), although I do have a new SRAM PC-1 sitting in the tool chest for eventual use one of these days.

Edit: I use a standard Park 3.x chain tool on my 1/8" chain - works fine.

regardless of your chain size (3/32 or 1/8) you can use a SRAM PC-1. they are dirt cheap and have worked well. i use them without a masterlink. any bicycle type chainbreaker can be used, AFAIK.

I'd rank Whipperman high , KMC & SRAM OK.. Full bushing type is longer wearing
than Bushing formed out of the side plate (bushingless) sorts.

since you dont flex the chain sideways you, may, (skill unknown) be OK, closing the chain with a chain tool ..

advantage again to bushing chains,, which have the pin the widest , sitting proud above the side plates..

Good to know, sure glad I asked!

How do I apply the 3% rule? I have a steel ruler. Thanks!

103% of 12" Is = ?

Is it true that an 1/8" chain when new will it measure 12" pin to pin over X links? When needing replacement it will measure 103% of 12" over those same X lengths?

Bike chains are on 1/2" pitch, ie the center to center distance between pins.

If you've got a 12" ruler you won't be able to measure 12" +3%, so line up the 11" mark... replace after 11-1/4 but before 11-1/2

Yep. Some 12" rulers have a 1/4" overrun so you can measure chain with it BUT

These 15s are cheap and have 2 inches of 1/64" hashes. I put the 13" mark on the edge of a pin, then measure past the 1" mark.

Westcott® 15" Stainless Steel Office Ruler | Quill.com

As for chain, I've gone master link, Power Link, Missing Link and no special link. Depends on what kinda mood I'm in. Currently KMC w/ master link on the fixie and Sram w/ all standard links on the coaster brake singlespeed.