Rime of the ancient Marin[er]

I've been meaning to build a single speed for a while, mainly because I have about 5 bikes already and none are single speed, but also because I genuinely don't need a geared bike for about 60% of the riding that I do (flat gravel, road and stony tracks). I don't like butchering bikes for parts, and the others I have are pretty much 'as they should be' but as I got this Marin as the frame only, it seemed a good opportunity.

So, a little progress (Poste Italiane is very slow). Thus far:

1. Marin Team frame
   
2. Mosso alu fork (26", +/- 750g, v-brake + disc) as I couldn't face buying a third Kona P2
   
3. Deore XT crankset (FC-M751)
   
4. Flite Titanium saddle
   
5. 26" NOS wheelset (DT Hügi / Shimano XT hubs, Bontrager Mustang rims)
   
6. Blackspire Snaggletooth chainring, 34t [plus a Raceface nw 36t]
   
7. Silver 27.2mm Shogun seatpost
   
   

Not sure on the following:

1. Bottom bracket (Shimano ES51 68mm octalink) any other options? Any idea on axle length?
   
2. Handlebar: Renthal, Raceface, Ritchey, Spank - very difficult to find in silver with a decent amount of rise
   
3. Stem: probably going for a Hope or similar with shortish reach, colour undecided
   
4. Tyres: God knows
   
5. Brakes: discs or v-brake? Could put a disc in the front, but know nothing about them. Avid, TRP, Magura, Shimano?
   
6. Rear cog: probably a Gusset or Surly single speed adaptor kit, 13t
   

As you’re doing a single n/w up front (presumably on a triple crankset) and a single cog in the back (presumably a Shimano HG freehub), I’d say that you have a nice bit of wriggle room for getting the chainline set perfectly.
Just find the matching BB for the M751 triple and not worry about it.
(Uh, make sure you match the BB width to the BB shell on that frame, obviously).

Brakes. How are you going to disk-brakify that NOS XT hub upfront?
Go for some boutiquey rim(e) brakes with the assumption an uncut Kona P2 is going to present at some point.

I didn't really make it clear but the XT hub is on the rear, the DT hub on the front has disc mounts. However, I think I'm only asking for trouble trying discs at this point, and I quite like the idea of some older Avid or BMX-style brakes.

What I'm really not sure about is the gearing, as this is my first single speed. I typically use my commuting mtb in the big ring (44t) and the small rear cog (11t) so I'm concerned about swapping for a 32/34t up front, especially if this is going to be mainly gravel focused.

Have you played with options at-
https://www.bikecalc.com/gear_inches
?

Yeah I had a quick look, seems as though I'm a sucker for grinding on the big ring so I might try for a 38t x 12t (or 13t) chainring/cog combination, as it will be (presumably) cheaper and easier to swap the cog should I find it too heavy going, or too easy.

I’d say, go with a larger rear cog, a 12t can wear out and start slipping quite quickly.

Yeah, I've read a little bit about it the last day or so and it seems the consensus is to go for a bigger rear cog to reduce wear and increase chain wrap. However, there seem to be far fewer larger chainrings available (greater than 38t) so I might wait until the last minute before deciding. There's plenty of work still to be done, so I have time to do some more calculations and testing.

Small update (been ill). Managed to source some mint XT M739 v-brakes from a French guy on Ebay, and these nicely match the cranks. Having a nightmare of a time trying to find a decent silver handlebar with 31.8mm clamping area, as I've settled on a Sunline V1 stem in black and it has the common clamping size.

There is a green Sixpack Millenium stem available locally but I'm not sure I have the audacity to use it.

One thing I'm not sure on: brake levers. Should I spend hours (days) tirelessly searching for some Shimano ones in decent condition, or just buy some Avids and spend the rest of the time looking for handlebars? Or, any other left field suggestions I hadn't thought of? *edit, bought some bars (Funn Kingpins) because they were €20 and have 30mm rise.

Second thing: how the hell can I remove the decals from these Mosso forks? They aren't the 'standard' type you can just peel off, or heat up with a hairdryer. Not sure I can bring myself to sand them off a brand new fork (despite their intense ugliness).

You could try nail polish to remove decals maybe?

I can try, but I think they are underneath a clearcoat. Might just leave them for the time being, I'll almost certainly make them worse if I try to remove them with any real effort.

A few more updates:

1. Bottom bracket (ES300 68mm octalink, 118mm spindles)
   
2. Avid FR5 levers (silver/grey)
   
3. Funn 60mm stem (silver/grey - gave up on the second hand ones, nightmare in Italy)
   
4. Funn Kingpin bars (30mm rise, black)
   
5. Tange Seiki J-27 headset (silver)
   
6. Lots of cleaning products, lubricants, grease and a spoke tool
   
   

I don't know if anyone else on here is in Italy, but seriously, the secondhand market here is ridiculous. People are asking pretty much the retail price for 90% of items that can be bought new from the various cycling sites, and eBay, great as it once was (in the UK at least), is now simply an extension of Amazon. Trying to negotiate/barter/haggle with people has been driving me round the bend. It seems people would prefer to keep an old handlebar rather than sell it for €5 less than they advertised it for. I see now why buying a house is causing me such pain. Rant over.

Some progress.

Had a change of heart. I didn't like the grey stem on the Marin, I need a silver one. Also, I don't want black bars on this bike. I won't be influenced by the total lack of silver bars available, I'll find a way. So put the Funn stem and bars onto the Maga bike, as the 30mm rise should make it a bit more comfortable.

Bought these, 800mm wide, 60mm rise. The Marin is slowly morphing into a big BMX. Anyone know of any decent, 0° stems in silver around 50mm reach?

(Scrap that, bought a Chromag locally)

Minor update while I try to get the bottom bracket and headset fitted.

So things got put on the back burner as I offered to rebuild a mate's bike, which was seriously neglected (I managed to pretty much empty my parts bin by substituting nearly everything, bar the frame and seatpost).

Regarding the Marin, I have now got the headset installed and the bottom bracket in, just need to source a chainring, pedals and the brake cables. Speaking of which, I'm thinking I'll go for Jagwire but not sure which - is there any reason why I shouldn't opt for the cheaper set, as opposed to the 'pro' version? And most important of all, what colour?!

This is going to be proper fantastic, love it already!