Jonneh

​I'm having a bit of a head-scratcher here, to the point that I'm sure I must be missing something embarrassingly obvious. I recently set my bike up with a White Industries Eno hub on a road bike frame (Cube Agree, BB86 bottom bracket with SRAM Red22 GXP cranks). After a while of enjoying it as a singlespeed, as I'm most used to from previous bikes (with their track hubs and fork ends), I today flipped the wheel and decided to head out for a spin in fixed gear. To my surprise, the chain line was way off being aligned, with the cog being about 8 mm closer to the centre line of the frame than the chainring (approximately, at least). This was severe enough that the chain would occasionally try to mount one of the cog's teeth ("Get a room!"). My fix involved bolting the chainring to the inside of the crank spider, which improved things, but now it seems like the chainring is a bit further in than the cog.

Fudges aside, my confusion relates to the spacing on either side of the Eno hub (supposedly 43 mm on the fixed side and 47.5 on the free side).​​ I never measured the chain line when using my freewheel (a Halo Clickster), but by eye it was pretty good, and there was very little in the way of noise (of which there is a fair bit now). How is this hub supposed to be used as a flip-flop if the spacing on either side of the hub doesn't give the same chainline? And beyond this mystery, what is the solution? It doesn't seem like there is any room for a spacer inside the cog, and turning the cog (also a WI one) around would move it in about 3 or 4 mm, putting it more or less in line with the chainring (when bolted onto the inside of the crank spider), but then the freewheel would be way out of whack, and there's no way for that to move inwards.

Am I missing something? Is there a fix?

Jonneh

OK, I got some hard numbers to inject into the situation, and they are as follows:

• The chainring spacing with the ring on the outside of the crank spider, as I usually have it (for riding singlespeed) is between 46.5 and 47 mm, or in other words, a pretty good match for the freewheel spacing on that side of the Eno hub (which I also measured and confirmed to be 47.5 mm with the Halo Clickster).
• The chainring spacing with the ring on the inside of the crank spider, as I needed it for a half-decent chainline riding fixed, was 41 mm. This compares to the rear cog spacing of 43 mm.

So my two options for riding fixed are 2 mm off (but then 6 mm off when I flip to the freewheel side) or 4 mm off (with a good chainline on the freewheel side). Four millimetres seems like too much of a mismatch, and unless they had another cause, the chain lock-ups I experienced (with just a 2 mm mismatch) when at high RPMs downhill support that seeming.

Anyone tried a 3 or 4 mm spacer before the cog and still got the lock-ring on securely? Else, how have you got this working?

P.S. I should mentioned, regarding the chain lockups I experienced, that the freewheel, chainring and chain are all new, and the chain tension is well-adjusted (1/2 an inch of vertical movement). Other details: 3/32 cog, 1/8 chainring and chain (KMC B1).

79pmooney

You could have some fun on this bike. Run it as a fix gear in (say) a 42-16 using the inside chairing position, Flip the wheel and have a super climbing gear of 36-22 using the 36 as an outside chainring.

I have a bike where I did this but took it several steps further. All fix gear. Crankset is set up triple, all 1/8" rings. I dished the wheel a little so one lines up with the middle chainring and the other with the outer, I then had made a double cog set (inspired by the Surly doubles but with the first cog flipped around so it sits against the spokes. I used a 21 and 17 for these. That inside cog lines up with the inner chainring. Crankset 46-44-38. Ususally rin a 14 for the small cog.

I run the bike as a 3-speed as above or skip the double cogs, flip one side and run it as a two-speed on the inner chainring for flat rides; usually 44 x 16/17 or the like. (17 is a low as I can go flipped, Smaller and the chain hits the spokes. There;s a little contact on the 17 but since the spokes and cog are always turning exactly the same speed, touching isn't an issue at all.)

Why the Enos is spaced that way is beyond me unless they were thinking double chainring. My Miche hubs are symmetrical (until I swap spacers around and dish them).

Ben

Jonneh

Oh, I like where this is going. Very much sow's ear -> silk purse (in the good sense).

I have at my disposal 17 and 18T cogs and the 16T freewheel, and 39, 46 and 53T chainrings. My favoured gear for all-around riding is now 46x16. I also prefer riding fixed for climbing. So I might plump for the 46T chainring on the outside, and the 39T on the inside, then flip the 17 or 18T cog (which will move it in 3 mm, giving a 40 mm spacing, which is just 1 mm from the 41 mm that the inside chainring position gives). So 46x16 freewheel for general riding, then 39x17 or 18 fixed for climbs. Do you pick up some extra-long chainring bolts to span the inner-spider-outer combo then?

The Eno spacing remains a mystery, but one with a silver lining thanks to that idea. Thanks!

EDIT: I'd still like to know what caused that chain locking while spinning downhill, which was a bit disconcerting. The locking up was transient (that is, it resolved when I started pedalling again), but was enough to throw my feet of the platforms. Not sure if the 2 mm mismatch in the chainline was just too much, or if the chain was a bit loose, or if it was something else.

Jonneh

Hmm, so I paid insufficient heed to chain length and the amount of play the Eno was able to take up (its range is limited by wheel clearance on the seat tube). Looks like a 42T ring with the 18T cog would use the same number of links as 46x16, so I'll try and pick one up. Sixty two gear inches will still be good for climbing. Triple stack bolts were fine, by the way, so no need for extra long ones.