I'm looking to build up a comfortable single speed with mtn bike style handlebars. Front disc brake, nice components, light wheels, carbon fork, carbon seat post, etc. I can't really find a full bike set up like this so that's why I'm thinking of building my own. But all the frames that excite me (paint, shape, overall look) are geared frames. The closest thing I can find in a full bike is the Bianchi Roger but the handlebars would need to be switched out. The frame I really like the looks of is the Kona Major Jake https://www.konaworld.com/bikes/2k7/MAJORJAKE/index.html
What would the cons be to using this kind of frame for a single speed build? What kind of chain tensioner would you recommend? Overall thoughts on this? The bike would not be used for any kind of racing. Just around town/city riding.

You're going for a SS cyclocross bike with flat bars? (I can only assume, because the Major Jake is a cross bike.)

https://www.irofixedgear.com/index.as...PROD&ProdID=12

Swap the bars and fork and there you go.

So you're basically looking to do a SS conversion. I turned my very old Litespeed Classic into a SS a few months back. I didn't care much for SS so now I've got a fixed wheelset on it.

Don't choose a bike with vertical dropouts, or you'll be limited to an Eno hub (expensive), or a chain tensioner (kludgy) to get proper chain tension. You want either horizontal dropouts or trackends. Most road frames made in the last 15 years or so are going to have vertical dropouts.

Yeah, that's the kind of thing I was wondering.
That eno hub doesn't look too bad. I guess I wouldn't mind spending the $150 on it if that's the best way to go?

I'm an ENO eccentric hub user. While I'm happy with it, in retrospect, I don't think it's the ideal solution. Getting the freewheel off can be difficult, sometimes unfortunately very difficult (and the fw puller tool on Sheldon Brown's website will NOT help you in many cases), and you have more porblems ajusting the brake pads, than with horizontal or track dropouts.

But let me say that better than horizontal or track dropouts, I think are sliding dropouts. And better than that is a frame with an eccentric BB shell. That's the perfect solution, whose time is coming.

Just get a Surly type chain tensioner and go with the geared frame.

FWIW, have you looked at the IRO or ON ONE Frames yet? They both have very nice horizontal dropout framesets.

Can you please explain that further? Why would I be removing the freewheel and why would I have problems adjusting the brake pads? Thanks!

You need to remove the freewheel if you want to change the gearing, or when the teeth on the freewheel sprocket are worn out. Or when the freewheel innards are broken or fine, abrasive dust has seeped in and done damage. And a milion other reasons.

You must ajust the brake pads every time the wheel moves around. With horizontal dropouts, the wheel moves in such a way that the distance between the rim and the brakepads remains about the same. In the case of track dropouts, the situation is somewhat worse, but not by much. In case of the eno, the wheel's axle moes "around" the axle in the dropouts, so the rim can take a lot of positions with regards to the brakepads.

Yep, running an eccentric hub and a rear brake can be a hassle.

also, if you're trying to make the bike "light" from your preference for carbon components, the eccentric hub adds much weight - although a convenient solution, definitely not a light solution

Ghost chainring/cog anyone?

i'd like to see the finshed product. my partner's starting to collect parts for a winter bike very similar to that, and it looks good so far.

Tried it. After the ghost chainring flying out at higher cadence, I decided that it's too risky. Maybe with brand new machined chainrings, but those I'd rather use as... umm.. chainrings.

Technically, thought, it does work.

I think the easiest thing to do is get the Roger and swap out the bars. Seriously, that is way, way easier than dealing with eccentric hubs, building custom wheelsets, and anything like that.

Is that really the case, though? I have just built a rear wheel with a Shimano 105 rear hub, and it felt about as heavy as the ENO.

A 105 Freehub weighs about 350 grams, and Enocentric weighs about 350 grams, so your observation is correct.

A surly fixed hub is about 320, and the ever popular $$$ Phil track hub is damn near 400g. A $$$ dura Ace 7710 low flange track hub is 298 grams. Weightwise the Eno falls right in the middle of available track hubs, and the weight difference is considerably less than the weight of a chain tensioner.