I was considering converting my mountain bike to SS. I'm wondering how well chain tensioners work for mountain biking and which one is best. I am considering three possibilities for the conversion on the rear:

1) Screw on freewheel type rear hub + chain tensioner
2) Screw on freewheel type rear hub + new frame that accepts eccentric bottom bracket
3) White Ind eccentric rear hub + disc brake bracket

Seems #1 would be the cheapest option, although probably not the best. Thoughts?

Option one is by far the cheapest, and works well for most mountain biking. Here in St Louis they run a weekly dirt crit series which is short fast cross country mtb races. There are people running that set up in all the classes, and there are guys that regularly win the A class with it.

First. Does your mountain bike have horizontal drop outs? If so, then you probably won't need a chain tensioner.

second, are you thinking of replacing your hub? or getting a freewheel

Freewheel goes onto the hub

Here's the cheapest method:
Take chain, brake chain, shorten to fit gearing you wish from the already installed freewheel on you bike. Attach chain. Everything is left alone, you just can't change gears.

Second:
replace freewheel with MBX freewheel. You can use the rear deraillier as a tensioner - if you need it

Third, total fix:
Bmx freewheel, chain tensioner - if needed, 1/8 chain, tappered crank and remove all but one chain ring. Cut or replace tappered bolts to keep chainring on.

It really depends if you need a chain tensioner or not.

Does your current rear wheel have a cassette or freewheel? https://www.sheldonbrown.com/free-k7.html

If it has a cassette, you don't need a new rear wheel/hub. Just get the chain tensioner of your choice and an SS cassette cog and a spacer kit to fill the gaps. If it has a freewheel, then get a SS thread on freewheel and re-space/dish the wheel as necessary.

IMO, it's not worth getting an ENO hub/BB for any mountain bike. A chain tensioner works just fine and doesn't super ugly like on a "road" bike.

But I vote for option 4: find the magic ratio. That's what I do on my bikes. No tensioner, no expensive wheels, just a little fiddling with gearing until I get the combo I want.

Found someone selling an entire single speed bicycle locally that has a White Industries ENO eccentric rear hub for only $100. The hub alone is worth more than that. I may buy that bike just for the hub.

Make sure the spacing is right for your frame, then flip the rest back on the market.

Yeah, I just realized another concern also. I think the eccentric hub is the regular version, not the disc brake version. And my frame has no braze-ons to mount a rear caliper brake.

Kind of a weird solution, but these work really well https://www.universalcycles.com/shopp...14&category=34

Interesting. I can't quite picture how it would attach to the frame, though.

Yeah, I don't think it'll work for me. There's no place to screw in a mounting bolt and I don't think the hose clamps would be enough by themselves.

So I picked up that other bicycle off craigslist last night. For $100, it came with a sweet single speed Sugino crankset and a White Industries eccentric rear hub. Those two parts right there are well worth the money. But the fact is, I've got an entire bike, and I'm not sure what to do with it. Ah, well. It was a good deal.

i had (very) bad luck with sprung tensioners on an SS mtb used for relatively serious XC. went to a fixed tensioner (rennen) that worked great, but made removing the rear wheel a bit of a hassle. when i tacoed the rear wheel, i bit the bullet and got an eno, which is so far superior to a tensioner that it is the only solution i would (myself) consider on future conversion.

The more I think about it, the more ugly a tensioner seems in my head.

The cheapest way is to get a tensioner and some ss cassette style cogs and spacers to use with your existing wheel. Just get a tensioner that works in "push-up" mode so your chain doesn't skip, like the surly.

With perhaps a half link and a little file/dremel work on the rear dropout you can run whatever gear you want. Just work carefully and make sure the axle nuts or skewer are nice and tight. Worked for me. Then again your frame might be more valuable then mine.