Double Fixed Wheel.

[Boon 51]

https://www.harriscyclery.net/product/surly-dingle-dual-fixed-gear-cog-17-19-teeth-3-32-2464.htm

This sort of sprocket
Just got to find somewhere where they are in stock

That's the one. Great.

 

[Boon 51]

What would be the supposed advantage to having them both on the same side?

Being lazy so you don't have to take the wheel out. lol

 

[T4tomo]

Being lazy so you don't have to take the wheel out. lol

what do you do about the chainline though - its either a bit out on both or a lot out on one?

and chain tension as you change sprockets?

 

[Boon 51]

what do you do about the chainline though - its either a bit out on both or a lot out on one?

and chain tension as you change sprockets?

Not worked that bit out yet, i was going to suck it and see but I have seen bikes with this set up.

 

[Milkfloat]

I assume if you use a chain tensioner then it would be convenient, that does not resolve the chainline though.

 

[Deleted member 26715]

I assume if you use a chain tensioner then it would be convenient, that does not resolve the chainline though.

But wouldn't that sort of defeat the perceived advantages of a fixed gear bike?

 

[Ian H]

A tensioner won't work with fixed. Neither will leaving the chain slack (or it might for a while until it comes off). So you'd have to slacken and move the wheel to re-tension each time you changed gear. Perhaps marginally less trouble than turning the wheel around. You would probably get away with chain alignment using a flexible derailleur chain, but it would be less than optimal.

 

[Milkfloat]

Actually ignore me - a chain tensioner on a fixed gear bike would be a really bad idea.

Edit: cross post with Ian. I just imagined trying to pedal backwards on a fixed gear with a chain tensioner, all sorts of pain came to mind.

 

[Sharky]

A dual fixed set up would be a solution for hubs which have a lock nut thread only on one side.

It may also have been a solution for TT riders in the 30's and 40's. I believe some riders when riding a straight out and back timetrial would ride a lower gear into a headwind and then turn the wheel to give a higher gear for the return leg. A dual fixed sprocket would be quicker than flip/flopping the rear wheel.

 

[Boon 51]

But wouldn't that sort of defeat the perceived advantages of a fixed gear bike?

Hi.. I'm not actually racing I only have the bike for fun so I don't have a fixed wheel just two free wheels which are 18/19 sprockets. Its just a great bike to ride.

 

[battered]

what do you do about the chainline though - its either a bit out on both or a lot out on one?

and chain tension as you change sprockets?

I've never met anyone who can set chainline to that degree of precision. You do need to reset the tension. A friend has this arrangement on her old French ladies' bike. Easy done. Racers used to do this all the time, pre derailleur.

 

[Hover Fly]

https://velosolo.com/dualcog.html

 

[All uphill]

Maybe I'm wrong, but...

I fancy building up my old Raleigh with a 16/18 combination at the back and with a 44/42 crankset. That way (in my mind) I'd get two gear ratios, constant chain length and two perfect chain lines.

Hmmm.