Thorn Cycles Forum

Community => Rohloff Internal Hub Gears => Topic started by: johnp on January 26, 2008, 04:35:40 PM

Title: Mount shifter on downtube?
Post by: johnp on January 26, 2008, 04:35:40 PM

Has anybody tried mounting the twistshifter in the downtube location where you would put standard shifters?  I'm working with a frame that has bosses for downtube shifters and it sure would be a clean cable run if I put the shifter on the tube and ran the cables under the bottom bracket and along the chainstay to the hub.

So before I attempt to re-invent the wheel I thought I would seek out the wisdom of those more experienced in these things than I am.

What do you think?  Am I nuts? :-\

Thanks in advance, John

Title: Re: Mount shifter on downtube?
Post by: stutho on January 28, 2008, 03:34:32 PM

Hi  johnp,
Welcome to the list,

I have yet to see a shifter mounted on the down tube; however, I did experiment for a few weeks with the position of the shifter.  I used a Minoura space grip - you may be able to use one of these to prototype the position.  For me the best location ended up  similar to that achieved by using a Thorn accessory bar - except I mounted my shifter slight further outboard.  (I tried several positions including the bar ends and the most weirdly position ever - pointing up next to the brake leaver.)

Best of luck and let us know how you get on.

Title: Re: Mount shifter on downtube?
Post by: johnp on January 29, 2008, 11:28:32 PM

I am in the process of putting the bike together so it will be a few weeks before I mount the shifter.  I'll post a photo if I can get something workable.  I had considered the space grip and may wind up using that.

Thanks for the encouragement.

Title: Re: Mount shifter on downtube?
Post by: johnp on February 10, 2008, 07:04:48 PM

I found a mount that works excellent for the shifter.  Here is a link to a catalog enty http://www.hostelshoppe.com/cgi-bin/readitem.pl?Accessory=1167173915

The clamp does not work on the frame BUT a little crude machine work using sandpaper wrapped around a lenght of PVC pipe of the corrrect diameter quickly changed the radius of the mount to match my frame tube.  The aluminum mount at ~65mm is just barely longer than the shifter.  The interal boss for the mount is high enough to clear the standard shifter boss on the frame.  It even comes with a 5mm stainless bolt that threads right in.  I made a gasket from 1mm thick plastic to protect the frame.  I replaced the attachment bolt with a 20mm long to give maximum threads into the boss.

I have a number of things to do to complete the bike so it will still be a while 'till I can try it.  I recognize that if I drop the bike hard and snag the mount I risk damage to the frame.  If I can find a clean way to clamp it on I will but it just looks so darn good now that I'm not sure I want to change it.  This mount provides a very short and smooth cable run that should provide the best possible shifting.

 ;D John