What crankset?

Can anyone please advise what crankset (and bottom bracket) to get for a Langster Pro frame?

Cr-Mo axle, 68mm x 103mm

This is what I have in mind but unsure whether they are suitable for a single speed bike?

SRAM S350-1 BB30 Chainset with X-Sync Chainring

SRAM S350-1 GXP Chainset with X-Sync Chainring

SRAM Rival 1 1x11 GXP Chainset with X-SYNC Chainring

SRAM omnium cranks

Or sugino dd cranks to go with your username

Is this because these are miles better or because of the fit @dancing james?

Noticed most Lagsters from pedalroom use Omniums.

Sugino SG75DD is nearly £300 on Dolan Bikes site.

Everything you wanted to know about bottom bracket standards, but were afraid to ask:

• Bike Radar
  
• Park Tools
  
• Slowtwitch
  
  

The BB you need is determined by both the BB shell and the chainset: it has to be compatible with both.

Your frame has a British/ISO bottom bracket shell, which is currently the most common standard.

You could choose cranks which use either an "internal" or "external" BB: internal BB have the bearings and axle inside the shell; external BB have cups which screw into the shell and hold the bearings outside the shell (the axle is part of the cranks).

The three chainsets you've linked to are all external, but the first one is for the BB30 standard and isn't compatible with your frame.

The other two would fit, but are both intended for 1x11 drivetrains, ie one chainring and an eleven speed cassette. You could use them singlespeed, but there are better choices.

SRAM Omnium are also external and a good and popular choice, but because of this second-hand prices tend to be unrealistic: buying new is better value for money.

DJ suggestion of Sugino 75 DD (also external) was tongue in cheek, unless you're a budding Chris Hoy or looking for maximum Instagram rep. :)

Cr-Mo axle, 68mm x 103mm

Those are the specifications for an internal bottom bracket: is this what you already have?

Thanks a lot for your comprehensive post @Scilly.Suffolk, it really helped!

Yes, that is the internal bottom bracket I seem to have on the frame according to their specifications.

Bit overwhelming for me but I got the basics and I think I'd go with the Omniums. I am a total beginner and this is my first build, having bought the frame already. I am pretty sure I will have many more stupid questions regarding one thing or another :).

You're welcome: BB are a nightmare.

103mm is quite narrow and I can't think of any track cranks that use that off hand: perhaps ask the previous owner what they used.

Ominous are a safe bet: if you do buy second-hand, budget for a new BB: the original has a patchy reputation, whereas the new, redesigned version is fine.

Search for "SRAM Omnium" on here: there are a couple threads covering things like BB and clearance.

Will do, thanks!

Will probably buy it new. Saving £30-£40 doesn't do it for me, I rather get a new one.

No previous owner, the frame is brand new, got my heart set on it and that's what I bought. I know, silly for a beginner.

It came with that BB fitted?

No @Scilly.Suffolk, it's just the frame by itself without any bb.