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Two topics - gearing and forks(6 posts)

Two topics - gearing and forksB2
May 2, 2003 1:09 PM
I'd like to convert a mountain bike to single speed. Not having any experience with single speed, I'm at a bit of loss with regards to available components to get the correct chain line and gearing. I'm thinking the gearing should be in the 70 G.I. range?? Any recommendations? Can you use the outer 42T ring (removing the inner two rings) on a mountain crank and go with maybe a 16 or 17 cog? Is chainline an issue with the outer ring? Any crank make / setup recommendations?

I would like to locate a more classic looking 1" lugged steel fork sized for a mountain bike. I currently have on of those older arched steel forks that look a bit funky in my opinion. Does anyone know if they make lugged forks for mountain bikes and where I can find one if they do?

Are you going to ride primarily off-road?Humma Hah
May 2, 2003 2:31 PM
SS MTBers usually use 2:1 gearing as a starting point, which gives something like 52 gear inches on their 26-inchish wheels, then adjust a little up or down to suit their physical condition and terrain. 70 gear inches would be a good choice for a general-purpose pavement pounder.

Off-road, if I used a 42T front, I'd use about a 21T rear (a hard freewheel size to find ... White Industries makes a very expensive one, and ACS Claws makes 20 and 22T sizes). You can pull apart a multi-speed freewheel (5-7-speed) or cassette (8 and up) and move the cogs around, add spacers, etc to build your own from whatever you've got. On pavement, you're more likely looking at something in the 2.3 to 2.6:1 range, depending on your hills and ability to spin. In really flat areas, some folks will venture up to maybe 3:1 gearing.

There are a huge number of ways to pull this off. Yes, you can eliminate the unused rings from the crank, pick one that seems to line up nicely with whatever you choose to use in the rear. Chainline does not have to be absolutely perfect, but it does help to get it as close as practical. The straighter it is, the more efficient, and the less likely you are to toss or jam a chain.

Have you been to Sheldon Brown's website, He's the guru of singlespeed and fixed gear, and he's associated with Harris Cyclery, which sells all the stuff you'll need. Sheldon has a huge repository of how-to articles that cover just the type of conversion you're intending. and also carry some singlespeed stuff. Shop at your LBS as much as possible ... some BMX hardware may serve your needs.

Also, roadbikereview has a sister site,, which has a very active singlespeed MTB forum.
Thanks Humma HahB2
May 2, 2003 5:07 PM
Actually I was thinking of riding primarily road and not much off road. I've just started browsing the two sites you mentioned. My current plan (I think) is to go real cheap and use everything I already have including a wheelset which I would install spacers and one cog. I'll have to buy a chain tensioner since I have vertical drop outs.

If I decide I like the concept, I would then start to upgrade with new crank, wheels, fork and bar. I don't like the looks of most of the chain tensioners I've seen so I was thinking about that eccentric hub by White Industries. Anybody have any experience with these?

Cheap is a mantra with singlespeeders ...Humma Hah
May 3, 2003 12:47 PM
... although some folks do throw money at their SS bikes, the essence of singlespeeding is the realization that a very simple, inexpensive bike can be more satisfying than a high-tech, high-dollar marvel.

All I have from White Industries is one of their high-dollar freewheels, and I haven't put it on the bike yet. Everyone who's used them that I've talked to swears they're first-rate.
Where did you buy the White Freewheel?Dave Hickey
May 4, 2003 5:50 PM
I've heard good things about them. ...Humma Hah
May 12, 2003 6:51 AM
... ten bucks cheaper than Sheldon Brown's outfit.

It feels really slick turned by hand, but I have yet to actually put it on the bike. I've got some major maintenance scheduled, including a new chainwheel and BB, and it will go on then.