Tandem Cycling - 26" or 650 carbon tandem fork?
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07-19-07, 08:30 AM
Does anyone know if such a creature exists? I'm working on a road tandem project for a pretty short team, and the frame builder says 700c won't work, but he can do 650c or 26". The team would prefer a carbon fork. Except for Wound Up, the makers of carbon tandem forks (Winwood, Alpha Q & Reynolds) are only listing products for 700c. Even wound up doesn't list a 26" size, but a framebuilder was trying to sell one on bike forums & ebay recently.
07-19-07, 09:56 AM
Interesting question - I know there are 650 carbon forks out there because there is a demand for them from the TT/triathlon crowd, but a tandem specific 650 carbon fork? Not sure...
Since I'm relatively new (both here and to the tandem world), what is the difference between a regular and tandem fork? Just "beefier" in some way?
07-19-07, 12:13 PM
You would probably need to send a note off to Calfee Designs (http://www.calfeedesign.com/contactinfor.htm) to find out what might be suitable.
If memory serves, Calfee built a 650c Tetra Tandem for Larry Black of MtAiry/College Park cycles back around 1999 and it was fitted with a custom / shortened AME Alpha Q fork. However, this was before AME was acquired by True Temper. Regardless, if anyone knows who is offering 26" or 650c composite fork that's suitable for use on a tandem, both with respect to its geometry and strength / durability, it would be the folks at Calfee... and/or Bob Davis at AriZona Cycles.
07-19-07, 12:56 PM
Since I'm relatively new (both here and to the tandem world), what is the difference between a regular and tandem fork?
About $100 - $150... Seriously though, sometimes there's not much difference if a cross fork or Clydesdale model was overbuilt to begin with and has a relative longish axle to crown length of ~395mm to allow for larger diameter tires.
However, when compared to conventional 700c road bike forks, tandem models usually have the aforementioned longer axle to crown length, usually use a larger diameter fork mold along with additional material, and usually use an alloy steerer or at least an alloy insert in carbon steerers. I say "usually" on all of these accounts because you will find exceptions, e.g., True Temper's Alpha Q X2 tandem fork has 374mm fork legs which is well short of standard tandem length and just a few mm longer than single bike length... which also limits your front tire size to 25mm.
The other thing to be attentive to is the fork rake and steerer tube size. For example, Santana uses 55mm of rake and a 1.25" head tube. The only fork that meets this exact specification is a carbon fork co-developed by Santana and Reynolds for Santana's tandems, the Ouzo Pro Tandem. Reynolds just recently started to offer that fork in a 1.125" steerer tube model. However, if you have a Co-Motion, a 55mm fork is going to alter your steering and handling just as a 45mm fork would alter a Santana's steering and handling.
Bottom Line: You need to understand the specifications for a fork on a given tandem before entering the market for a carbon replacement model. You may or may not a fork model that fits those same specifications and once you start to diverge from the OEM fork spec you need to understand what the trade-offs will be in terms of handling and clearances.
For recumbents with small wheels I've seen forks with legs being cut down and new dropouts glued in. Not something I would consider myself though, since it's safety critical and bonds aren't always easy to get right. The tolerance of the joining parts, materials and gluing procedure are things that carbon bike manufacturers have sometimes struggled with! Another issue is whether the area you're gluing into is designed to accept stress from the dropout.
I've had useful emails from AME's technical Engineer, who may be able to help you out here, or at least give advice. See AME's website under 'contact us' for his details. If you're lucky he may be able to provide you with a test lab special.
Another alternative would be to use a rigid cross country MTB carbon fork. Pace make one, but the aesthetics wouldn't work I think.
Best option is to remember that aero always beats weight (ignoring comfort) and get a narrow-bladed steel fork. Argos cycles in the UK make one with extremely narrow blades which looks good.
Winwood still shows a 26" carbon fork. http://www.winwoodbike.com/purist.html the axle to top of crown is 420 mm
they also show a carbon fork that is tandem approved. http://www.winwoodbike.com/muddydisc.html this fork has an axle to top of crown length of 398mm
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