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Off the back
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Discussion Starter · #1 ·
I'm considering building a fixie and have a special purpose for the bike. Every year, I race the Mt Washington hillclimb. I have a tripple on my road bike and really only eve use the inner ring for that race and training for it.

What I'm considering for a fixie is:

1.) Flip flop ENO hub with a 16 on one side and a 24 on the other
2.) A triple crankset with a 24 ring inner and a 42 ring outer.

If I flip the hub, the chain line will move a few mm up front. It's not a ton considering how far "crossed" your typical 9speed chain gets.

Can this work? Can this work if I use a horizontal dropout frame? A singelator and vertical dropouts? Would it work much simpler if I use a regular 135mm 9speed rear hub and spacers?

2 different chains with SRAM disconnect pins is how I imagine taking care of that problem. I'd probably set up the bike at home or take 10 minutes on the road to swap it over.

Ideas please.
 

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pitt83 said:
I'm considering building a fixie and have a special purpose for the bike. Every year, I race the Mt Washington hillclimb. I have a tripple on my road bike and really only eve use the inner ring for that race and training for it.

What I'm considering for a fixie is:

1.) Flip flop ENO hub with a 16 on one side and a 24 on the other
2.) A triple crankset with a 24 ring inner and a 42 ring outer.

If I flip the hub, the chain line will move a few mm up front. It's not a ton considering how far "crossed" your typical 9speed chain gets.

Can this work? Can this work if I use a horizontal dropout frame? A singelator and vertical dropouts? Would it work much simpler if I use a regular 135mm 9speed rear hub and spacers?

2 different chains with SRAM disconnect pins is how I imagine taking care of that problem. I'd probably set up the bike at home or take 10 minutes on the road to swap it over.

Ideas please.
Single speed or fixed? Options are greater with a single speed vs fixed.
 

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NeoRetroGrouch
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6,491 Posts
Some ideas...

First, I would not run an off-line chain without something (derailleur, singulator, etc.) to hold it on.

I don’t know about the ENO hub, but if you were to use something simple, like a basic Suzue flip-flop with fixed-fixed (does this exist), you can change the spacers from one side to the other and end up with a slightly dished wheel where the location of the two cogs is “spaced” the same as the chainrings. You would probably then have to play with the BB to get the rings lined up. I would think this would be workable with any cone-and-cup fixed-fixed hub.

For a SS (not fixed) you could use two cogs on the same side with the correct spacing as above.

For both, the most elegant solution would be where the two combinations (big front–small rear and small front-big rear) resulted in the same chain length.

I have seen the SS version done. He normally ran the big front-small rear (something like a 39-16) but had the small front-big rear to limp home if he absolutely blew up. It was a standard freehub with spacers and cogs and he didn’t bother to line up things or match the ring and cogs for chain length. He just used the allan screw adjuster on the singulator (or similar) the move the chain placement back and forth.

FWIW,
TF
 

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Discussion Starter · #6 ·
That's kind of the idea

TurboTurtle said:
First, I would not run an off-line chain without something (derailleur, singulator, etc.) to hold it on.

I don’t know about the ENO hub, but if you were to use something simple, like a basic Suzue flip-flop with fixed-fixed (does this exist), you can change the spacers from one side to the other and end up with a slightly dished wheel where the location of the two cogs is “spaced” the same as the chainrings. You would probably then have to play with the BB to get the rings lined up. I would think this would be workable with any cone-and-cup fixed-fixed hub.

For a SS (not fixed) you could use two cogs on the same side with the correct spacing as above.

For both, the most elegant solution would be where the two combinations (big front–small rear and small front-big rear) resulted in the same chain length.

I have seen the SS version done. He normally ran the big front-small rear (something like a 39-16) but had the small front-big rear to limp home if he absolutely blew up. It was a standard freehub with spacers and cogs and he didn’t bother to line up things or match the ring and cogs for chain length. He just used the allan screw adjuster on the singulator (or similar) the move the chain placement back and forth.

FWIW,
TF
Right 42t,130BCD front, 16t cog rear line up "balls dead on" because I've got it spaced away just enough. When I flip, the large rear cog (Could I go 24 or 25 to get 1:1 for mountain climbs?) and the small ring (24t w/ 74BCD) line up.

I'll check out the Suzue hubs; thanks for the pointer. I'd prefer double fixed, would live with fixed /SS flop, less excited about SS/SS double freewheels.

I don't know if I'd have to mess with the BB? Couldn't you just live with that 3-4mm spacing away from the frame and the other in a bit tighter? Probably wouldn't notice it.

Excellent point about chain length. Possible, but really elegant if you'd get it right.

Right now the bikes completely etheral so anything's possible (except a Dogma Ego frame). Would love Ti if $$$ allow. Complete novice about this world. It's supposed to be less complex, but it's like learning a whole new language.
 

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NeoRetroGrouch
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6,491 Posts
pitt83 said:
Right 42t,130BCD front, 16t cog rear line up "balls dead on" because I've got it spaced away just enough. When I flip, the large rear cog (Could I go 24 or 25 to get 1:1 for mountain climbs?) and the small ring (24t w/ 74BCD) line up.

I'll check out the Suzue hubs; thanks for the pointer. I'd prefer double fixed, would live with fixed /SS flop, less excited about SS/SS double freewheels.

I don't know if I'd have to mess with the BB? Couldn't you just live with that 3-4mm spacing away from the frame and the other in a bit tighter? Probably wouldn't notice it.

Excellent point about chain length. Possible, but really elegant if you'd get it right.

Right now the bikes completely etheral so anything's possible (except a Dogma Ego frame). Would love Ti if $$$ allow. Complete novice about this world. It's supposed to be less complex, but it's like learning a whole new language.
The Suzue basic is a good experimental hub; it’s cheap in both senses.

The BB adjustment I was talking about was to get the rings lined up with the cogs. 1) First you would get the hub to the right spacing, if necessary, by adding/subtracting spacers. 2) Then you would get the cogs to be “spaced” the same distance as your chainrings are spaced by moving spacers from one side to the other. This locks in the position of the cogs. 3) Now you would adjust the BB to get the chainrings in line with the cogs. You could also put a spacer or two between one of the chainrings and the spider and go back to step 2. When you get it right, dish the wheel.

Ti is kind of limiting, as opposed to steel, because you are stuck with the rear end spacing of the frame. (Same with Al.) Ti track frames do show up on eBay every once in a while. This would give you the most options on a fixed/fixed hub, I think. Ti MTB is common and there are quite a few hubs now being made at 135mm (like the ENO). Road frames would give you the least options, though you could re-space hubs if you’re up to it. Also, a fixed adapter (see Sheldon) would work on a road hub or a MTB hub.

The Ego is not in my future either. Can you imagine being able to SS a DeRosa Cinquanta. I think that would be my dream build. Why did you bring this up, anyway? Now you have me lusting again.

TF
 

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Arrogant roadie.....
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4,232 Posts
Maybe, but it's too complicated

I have a 2-speed 2-ring setup with my fixed/free flip-flop hub. I run a 16 tooth fixed with a 45 ring, and a 18 free on a 42 ring. The bigger ring sits inside on an old Shimano 600 crank, the smaller on the outside. I do it this way because the freewheel (Shimano BMX) sits a bit farther out than the fixed does on a zero-dish wheel. Strange, but both chainlines are dead-on. I have short horizontal dropouts, and with a half-link, both combinations fit well inside the slot.
 

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NeoRetroGrouch
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6,491 Posts
Nice use...

of a basic design flaw. I cannot figure out why flip/flop hubs don’t line up. Just plain-a$$ed cheap, I guess.

TF
 

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Discussion Starter · #10 ·
I think I have to give up anyway

What's the deal with using road rings and cogs? Can't do it because of the thickness, right? Also, since the chain is bigger, SRAM disconnects won't work either. If I go with SS / BMX hardware, the largest cog I've seen is a 20 and the smallest ring a 34. Nowhere near the 1:1 gear ratio I'm after for this.

Thanks for the help. If I'm way off with this conclusion, let me know. If I could sneak it past the wife, I'll probably build a fixie anyway. This was an attempt at, "You know 'hon, If I had a bike like this, I could___________(Insert your favorite excuse here)"
 
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