Friday, October 7, 2016

Tiller and Stem: Bacchetta Stick Bike

A year and a half ago I modified my Ti Aero and CA2 steering setup from a stock riser and handlebar to a tiller and stem.  

This is a pic of the stock riser and handlebar setup: 


I found that the riser impeded my ability to see ahead of me.  That was the primary basis of my interest in the Cruzbikes.  This is a pic of one of the three (Vendetta, Silvio and Sofrider) Cruzbikes I owned (Silvio): 

The front wheel drive of the Cruzbike is problematic for me for several reasons I won't describe here.  I returned to the Bacchetta stick bike frame and rear wheel drive.  

I then became interested in a different bike that had both a tiller setup and rear wheel drive, the M5 Carbon High Racer (pic): 



But I chose against this bike for two reasons: didn't want to spend the money and the chain interferes with right hand turning (wheel hits the chain).  In my terrain the fast, descending switchbacks would pose a problem with the chain / wheel issue.  

My compromise response was to modify the Bacchetta bikes I have to obtain a) the tiller and stem setup, b) a much more reclined seat, c) retain the rear wheel drive.  This is a picture of Kent Polk's initial use of the tiller, stem and custom make reclined carbon fiber hard shell seat: 

I ordered from Kent the Railgun seat for both my Bacchetta bikes.  It makes a profound beneficial difference.  I then ordered the tiller and stem setup from Performer Bikes in Taiwan.  

Others using the Performer Bikes tiller and stem modified it so that it angled down to the level of recline the rider wants for the Railgun seat.  So that the tiller stops, and doesn't land in your lap, others had drilled a hole in the stem and inserted a strong bolt.  This is a pic:  


Two things to note on the picture above.  First, in order to get the angle at which the tiller `fits' the rider's preference I had to tap several holes, experimenting.  Second, given that I didn't want the strong bolt hitting the stop point on the stem (metal on metal) I had to `cushion' the stop point with pieces of strong rubber, lashed to the stem with cable ties.  

Quickly I concluded that the bolt, rubber and cable ties was not a long-term solution.  In fact, after a long and dangerous cycling event (Hoodoo 300) the bolt simply fell out on a training ride.  

To eliminate this problem I welded a piece of aluminum to the tiller and welded an aluminum channel into which I inserted a `soft' stop (again, strong rubber):  





























I am able to adjust the angle at which the tiller stops simply by adjusting the length of the rubber inserted into the stem channel.  The rubber is firm and snug in the channel eliminating the possibility of falling out.  

You will also note that I welded the tiller itself to the stem.  Previously it had been attached to the stem with a simple seat clamp.  That is problematic.  The seat clamp can loosen and the tiller and handlebars can swivel, completely eliminating steering control.  


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