How is this possible without a long cage rear d駻ailleur?

[Nags&Ducs]

I can't see how the derailleur could possibly take up enough slack on the chain with this set up. Am I missing something?

[Pastashop]

What's the tooth jump?

FWIW, one of my bikes has a 30/46 chainset with a 12/27 9sp cogset, running normal FD and short cage RD. Works fine. But also, I'm not cross-chaining, so...

[oldpotatoe]

I can't see how the derailleur could possibly take up enough slack on the chain with this set up. Am I missing something?

Hard to tell without it being small-small and see how much chain droop there is. Suspect a lot.

[Mark McM]

If I'm counting teeth correctly, the chainrings are 46 & 28. If so, the chainring differential is 16 teeth, which is standard for most compact cranks (50/34 or 52/36). The cassette looks fairly standard - maybe a 12/25 or 12/27. A short cage derailleur usually works fine with a compact crank and standard cassette, so there may be no need for even need a medium cage derailleur, let alone a long cage derailleur.

[stien]

Looks like a sheldon brown setup to me. I seem to recall using the small chainring with smaller cogs is a no-go, but is fine for climbing (using bigger cogs).

[sandyrs]

If I'm counting teeth correctly, the chainrings are 46 & 28. If so, the chainring differential is 16 teeth, which is standard for most compact cranks (50/34 or 52/36). The cassette looks fairly standard - maybe a 12/25 or 12/27. A short cage derailleur usually works fine with a compact crank and standard cassette, so there may be no need for even need a medium cage derailleur, let alone a long cage derailleur.

Isn't that 18 teeth?

In any case, yeah, with a fairly narrow cassette range that combo seems at least plausible, though it may not look right to the eye.

[bicycletricycle]

I suspect it doesn't work in the small small range. With that kind of gearing the small ring is used mostly for a bail out .

[oliver1850]

I believe that's a Cyclone Mk. II RD. If it's the long cage GT version, max wrap is 34 teeth. If the crank is 28/46 and the cogs are 13-26, that's 18 + 13 = 31, so well withing the range of the RD. The short cage capacity is 28 teeth so if that, it may not work small/small.

The long cage version does not look all that long:

http://velobase.com/ViewComponent.aspx?ID=374D02A0-8E7D-43FD-8AE3-A04877256F81&Enum=108&AbsPos=45

Looking closely at your photo, I think it's the short cage M II on the bike. Still may work, depending on actual tooth counts. Some derailleurs will comfortably run more than their specified chain wrap.

[Pastashop]

I suspect it doesn't work in the small small range. With that kind of gearing the small ring is used mostly for a bail out .


+1. Similar set up on my Ebisu 650b bike and I'm basically in the big ring 95% of the time whether on the flats, rolling hills, or gravel.

[Hindmost]

The small ring will work with most of the cassette. I imagine that by the time you try small to small there is interference from the big ring.

[Ralph]

No problem....if necessary....you just set it up with small chainring only working on larger rear cogs. Same principal as using a short cage with a triple.

[Nags&Ducs]

Even small ring to big cog seems like it would have excess chain. Never mind small to small range.

I saw this ti randonneur on the local CL and it gives me inspiration to build something similar when I am off sanctions.

[pbarry]

Long ago, mid-seventies, I was taught not to shift into the big/big or small/small, even with a corncob freewheel, unless one really needed it in a race. Always worked fine for me.