I just purchased a Trek 1000 older model and would like to keep the crank set with both gears. I have seen where there is a fixed rear hub with a derailleur but I cannot find an article on how to do it. Any help would be appreciated.

This is singlespeed/fixed gear (emphasis being placed on the "single")

Fixed hubs generally do not work with derailer mounted chain tensioners, which would be required to use both front rings as the difference in size would cause signifigant chain slack.

https://harriscyclery.net/itemdetails.cfm?id=2464

Put one of those on the rear.Two chainrings on the front that keep the axle in the rear dropouts and you're good to go.

Thank you.

I ran a two speed set up on my Crosscheck for a while. I had a FSA double with cyclocross rings (48 and 38) up front, a Novatec single speed FREEWHEEL MTB hub with a 16 tooth sprocket in the rear, and a Paul's Melvin chain tensioner in between to take up the slack.

I stressed FREEWHEEL MTB hub, because I've never seen anyone run an effective fixed gear set-up with a derailleur, or any other kind of chain tensioner. As far as I can imagine, if you tried to back pedal on a drivetrain with that much slack in it things would get interesting in a hurry.

The Paul's Melvin tensioner I used resembles a rear derailleur, because it routes the chain the same way, but is built much lighter since it doesn't have to actually shift the chain between gears.

The two seed was fun for a while. I certainly never saw another one coming the other way. And I guess the novelty of the thing was it's main attraction. But I went back to a single speed after a while because even with a perfect chain line, the Melvin produced at least half the clatter of a bona fide rear derailleur - which is too much. I had also grown tired of shifting the chain between front rings with my finger and fitted a front derailleur... slipping over to the dark side... not really.

For those times when I simply must have a few gears I built an 8 speed rear wheel that I run with a single 42 tooth ring up front. It takes about a half an hour to install the geared wheel, a rear derailleur, grip shift and longer chain. The bike can be restored to single speed duty even quicker.

DanO

how about the dingle cog by surly? or do you want to shift on the fly?

I would like to be able to shift.

Isn't there a way to convert a SA three speed hub to a two speed fixed? I thought that I read about that either here or on Sheldon's page.

Found it. Conversion of a Sturmey Archer AW three speed hub into a two speed fixed gear hub.
CLICK

You could make a single-cog dual-chainring setup pretty damn easily with a chain tensioner.

What parts would be needed?

Could the two gears on the crank be left on and a fixed gear on the rear and use a Surly singulator for a tensioner and shift back and forth with the crank gears?

it's not fixed, but I always thought retro-direct drives were interesting. Pedal forwards and you have one gear, pedal backwards and it is a different gear.

as for why you can't shift with a fixed it has to do with how long it would take a change in pedal movement (when you resist for instance) to translate back to the real wheel, assuming that you have it absolutely dialed in so that you don't need to worry about your chain falling off.

SRAM/Sachs T3 converted into a two speed fixed (big mamu download):

https://www.fixedgeargallery.com/arti...amwebster1.pdf

TCS