I think that’s quite high. Typical track is mid-high 80s” so something like 48:16 or 49:15 – are you riding as fast as you would on the track? I doubt it.

Most people who ride singlespeed/fixed in the winter do it to keep their cadence up and get a nice smooth peddling action, be kind to your knees (particularly in the cold) and develop a nice fluid style so you can sneer at obvious MTB peddle-mashers when you are commuting.

I ride 48:16 on my commuter which is 26″ wheel so a 78″ gear.

Pros are that I can sit comfortably at 20mph on the flat bits. It also improves my climbing ability and strength.

Cons are that it is flippin hard work to get it up hills. Normally it’s fine but doesn’t allow for days when you’re tired or the weather is bad. It’s virtually unrideable in snowy weather as it spins the back wheel.

Other big disadvantage is pulling away from lights as you need to put in a lot of effort to get up to speed.

I find it fine, I have the option to go to 18 or 20 on the back during winter.

So 50 on the front would be ok as you could all the way up to 20t on the rear to find a suitable gear.

There’s no such thing as “a 50″ crankset” – you mean a 50T chainring? No-one’s used a 50T chainring on a mountain bike since about 1992, so I assume this is a road bike… but then you have an XT hub you want to fit, which won’t go in a road frame, so – basically – WTF are you talking about? 🙂

Erm, where did the OP say it was a road frame? 😕 🙄

And an XT hub can be fitted with a 130mm axle.

I don’t ever remember 50t being a popular easily-available chainring size in 1992… 🙄

Ahem….