Tandem Cycling - Suggestions for build please, Tsunami 26"
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11-03-08, 02:09 PM
Okay, I need help selecting front and rear deraileurs for my new build.
The frame as most you know is the Tsunami 26inch mountain tandem that I will build in a road style.
Wheels have Shimano 9 speed compatible hubs.
I need advice for the front and rear deraileurs.
The cranks are Truvativ (SRAM) Elita GXP Tandem 170mm 52/39/30t.
I haven't decided on the exact cassette yet, not sure of gear range yet.
I'm hoping to go with Campy Chorus brake levers/shifters and use a JTEC shift adaptor so I can then use a Shimano rear deraileur thats obviously compatible with a triple setup.
Any suggestions for a front and rear deraileur?
Sorry for all the questions but I've never built up a tandem or a triple before.
General derailleur advice for building up a road tandem:
1. Use a road triple up front, with the correct curvature for 52-53T.
2. Use an MTB derailleur in back, preferably with the needed cog capacity and a lot of chain wrap (long cage rear derailleur). Many people have forgotten about chain wrap, because the specifications are no longer to be found in the catalogs. For Shimano at least, I think that can be found at their website. I have found that shifting quality does not suffer when using an MTB RD on a teeny-tiny (11-21) road cassette.
Do not be surprised if after you have the shifting adjusted to perfection on the workstand in the garage, you find that with riders on board the indexing is now imperfect--the frame bowed with two-up riders.
When I tour in Colorado, I often put together a chainring and a cassette intended specifically for that use--if you are only going up and down, you don't need the middle. My experience on a single bike has been that the road FD will shift across 24-36-50 satisfactorily if you slide it down the seat tube a little, and that the road RD (Ultegra triple) will handle almost all of the chain wrap. With this adjustment to the front, and a 12-27 on the back, the steeper portions of Rocky Mountain National Park, Cottonwood Pass, and the Mount Evans race can be handled at a competitive rate. No other drivetrain changes were needed. Note that the 24 X 27 low gear gives less than one-to-one gearing on 700C wheels.
11-03-08, 03:39 PM
You might ask Zona or Merlin about this as they have more expertise than I do. However, for what it is worth...If you have a Shimano rear hub, you should probably go with Shimano components. If you go with Campi, you will probably get a 9/10 speed brake/shift lever and deraileur, which won't match up with the Shimano cassette. You will need the JTEC adapter and it works really well. I had Shimano cassette and Campi Chorus brakes/shifter/deraileur with a JTEC on my first tandem and it worked well.
Don't know how hilly your area is, but you might want to consider going to a mountain bike cassette. An 11/32 cassette should work with a 30 tooth gear, but you need a long cage on your deraileur.
A 10sp cassette will also fit on a Shimano 9sp hub.
IRD now has an 11-30 and a 12-30 10sp cassette (along with their 11-32 and 11-34), you may want to consider. However, the 11-32 and 11-34 has not been getting good reviews because of rough shifting. I have not seen a review of the 11-30 and the 12-30 but they may shift better with the smaller jumps between gears.
11-04-08, 09:34 AM
I've decided to save a few bucks and go with Shimano bar end shifters and use a set of Campy Record brake hoods I already own. I purchased a Shimano 105 triple rear derailleur and Shimano Cantilever brakes. The 105 will accomodate up to a 28 t cassette. I'll never need anything larger than that.
I'm going to wait on the front derailleur since I'm not 100% certain about the clamp diameter. Probably go with a Shimano front derailleur as well.
Almost forgot, a Shimano 12-27 Ultegra cassette.
thanks for the input.
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