barensadau

Hi,
I'm riding a vintage bike with suntour cyclone derailleurs and friction downtube shifters

I have toured on it, but want to make some changes.

first off, I have two rings on the crank: 52 and 42, I believe. This makes climbing big, big, steep hills with gear harder than it needs to be. I'd like to put on a three ring crank.

anyone know if I will have to change my front derailleur to accomodate for this change?

Also, I'm riding on a six speed freewheel, and was wondering if anyone who has ridden on similar and upgraded to casette thought it was well worth it. My frame is steel, so it can potentially be spread back there.

Thanks!

rccardr 

You will most likely have to change the FD to one with a broader spread range and with a cage that can accommodate the smaller ring. A Cyclone MkII triple would be a good choice, they are out there for $20 or so and the clamp (unique to the FD) fits 31.8 down tubes but you can use a shim adaptor to bring it down to 28.6 if that's the size you need. To go with that, you could mate up an SR Apex, Sugino or Sakae triple in either true triple (48/38/28) or half step plus grany (48/44/30) ring sizes. They can be found for about $45. Keep the six speed and friction setup- with the triple it will give you lots of gearing options- but if you need a wide ratio freewheel they can be found for under $25, plus another $8 or so for the FW removal tool (or have the LBS take off the old one). That way you keep the Suntour Cyclone type setup at a low cost.

You can PM me if you need more help, or go to the C&V forum.

vinfix

I have a Cyclone MKII RD, I selected it for a vintage build because of it's wide range. I'm using it with a 7 speed freewheel up to a 28T.
I also have an '84 Schwinn LeTour Luxe with a triple that works well with the stock Suntour Mountech.

DannoXYZ 

Are you doing the labour to upgrade yourself or paying a shop?

TLCFORBIKES

Go with a triple FD & RD and a new chain (you will need more chain links to original chain if you do not use a new chain). I bet you are looking forward to spinning up the hills vs grinding up the hills.

nwbikeman

You might not need to do a full swap. Some of these cranks were drilled for a triple ring, you didn't mention what the crank is but it should take a 39t inner ring possibly smaller depending on the bolt circle diameter of the crank. As for the rear deraileur it will sometimes take a lot bigger cog on the older frames because some frames had a longer distance between the axle dropout and the hangers mount. I have several bikes with a short cage rear deraileur shifting a 7 speed freewheel with a 12-34 and does not bottom out on the deraileur with a double crank. if you have about a 1/4" between the high gear cog and the frame you should be able to mount a 7 speed freewheel to you stock wheel as well.