JunkYardBike

Does anyone know the capacity of the Suntour Cyclone Mk II? On another C&V thread, I saw 18T mentioned, but looking through old Trek brochures, they seem to have been used on 50/45/28 chainring setups, a 22T difference.

I have a NOS 1983 model (they were spec on 1983 Treks) that came in a box labeled "Touring". I'm not certain the box is original to this specific FD, however.

Also, as it appears to have been used on cranksets with 52 and 50T big rings, would it be inadvisable to use a 46 as a big ring? And is a half-step granny (ala Trek) the ideal triple setup to use with this particular FD?

mrmw

Here are some partial answers:
--my Mk II (touring, v.1982) came stock with a 52-46-34 setup.
--From research, the stated capacity is 18t.
--I'm running it now on a 48-38-28, 20t. It works really well.

I don't know how it would work on a 46 tooth largest chainring, but I'm curious too.

JunkYardBike

Well, that's good news. Maybe I'll be a guinea pig and try the 46T. I'd like to get a low of 26T, which would allow me to push the rear to 30T (using an Mk II RD, as well, which I've read others have pushed to 37T chain wrap capacity). Actually, I'd rather have a high of 50 and a low of 26, but that probably won't work. I might try a 50T high and 28T low (to really push it), and something intermediate, like a 40 in the middle.

John E

When matching a front derailleur to a set of chainrings, one needs to know both the double and the triple shift capacity. If the advertised capacity is 18T, you should probably make sure the middle ring is no more than 18T larger than the granny.

The biggest drop I have ever tried with a close-ratio road front derailleur (a Shimano 600, which is probably comparable to the Cyclone II) is 52-48-34, which seems to work fine. I was delighted with my previous setup, 48-45-34 / 13-15-17-19-21-24, with the Shimano 600 in front and a short-cage Cyclone II rear derailleur.

JunkYardBike

Ah, that's good to know. I believe this derailleur is designed to work on triple rings. I wouldn't go over 22T total difference (between large and granny) anyway because of chain wrap capacity limits on the Cyclone RD (though I've read elsewhere that tooth difference between the granny and middle ring can virtually be ignored in calculating chain wrap if you are careful never to run granny ring with small rear sprockets.)


That last setup sounds like a half-step plus granny, right? I'd be looking for a relatively low gear, though, as a bailout. I manage riding around here with a racing 52/42 front and wide range rear 13-32, but the geography is such that occasionally I'll run into an extremely steep but short hill. Hills are erratic rather than rolling where I ride.

So, I'm considering a half-step plus granny like 50-45-28 on front, with a 13-28 (or if I can ignore the granny in calculating chain wrap, maybe up to a 32 in the rear).

Or, maybe I should just run a double up front, like a 50-36, with a 13-32 out back, though the steps on such a setup would be pretty drastic.

Absenth

Going to perform a little thread necromancy here. Sorry about that in advance.

I have the Cyclone Mk-II FD and long cage RD on my '84 Trek 520. I'm wondering, if I put a 9 speed rear cassette on the bike am I likely going to be able to shift through all 9 speeds with the friction shifter?

Or should I start saving towards new derailleurs if I'm going to go that route? I'm really having difficulty adjusting to the Half Step plus granny setup that's on the bike now.

5cagm

I remember hearing someone say that they could do 8 speeds but I'm not sure about 9. May as well just give it a try if you're committed a 9 speed wheelset regardless.

JunkYardBike

Change your front rings to a wide range triple. The Cyclone can handle it, though sometimes shifts from the granny to middle are a little rough. With practice, though, it becomes smoother. In my experience, the MKII RD has limited range: I couldn't even get it to cover a 7 speed cassette, let alone 9. Some people have remedied that problem by filing the stop, but I was unwilling to go that route on my mint example.

Absenth

I'll start out by building my wheel and getting the new crankset.
If it works, Fantastic I've got a much newer drivetrain that I understand better than what I've got.

If the Suntour Mk-II can't handle it I'll put the current parts back on the bike, and wait until I can get a new set of derailleurs front and rear.

That way I can always return the bike to it's vintage state by re-installing the original parts.