March 19, 2007

Getting back to my pre bypass surgery cycling level has not been easy.  Previously I was always able to hang with my group without too much trouble in the 23-26 MPH range.  Now, I am finding that 22 is about as fast as I want to go, perhaps it is because I don’t really want to try.  My recovery heart rate is not as rapid as it used to be, but I am not worried as all tests are quite normal and the docs are very pleased.  Guess I have to blame it on old age.  Added to that, I am still here which is more important!

I bought the frame from Dana complete with the VK flip-up tiller and handlebar, carbon seat and the TerraCycle over/under idler with titanium cog.  More on this later!  The quality of this VK product is very high.  I had two other VK products, and Kamil’s (Velokraft) workmanship has greatly improved.  The finish is very glossy and deep and is heads up better than his early bikes.  As for components, I had two 650 Spinergy X-Lite carbon wheels and a carbon fork.  I also fitted it with my Rotor Cranks which I took off of my Baron Clone. I used SRAM twist shifters and a mid quality Shimano brake in the rear and a Bacchetta pull down in the front.  The geometry was almost equal to my BC and my XPort shown here.  On the VKHi the seat/BB difference is a bit over 6 inches, whereas on my lowracers it was over 7 inches.  The seat height, however, on the VK was about 5 inches higher.  Initially this took some to get used to, and is what made me consider a smaller front wheel.

The first PICS show the VK flip-Up tiller with handlebars.  A truly beautiful piece of engineering!  Super light and perfect fit on the steerer tube.  Having said all that, it did not work for me.  I am a stickler for stiffness!  I tend to be a masher on the cranks (as opposed to spinning) and when I am mashing I am also pulling on the bars.  This set up proved to be much too elastic for me.  I did not feel comfortable with the amount of “give” in the system.  I also did not need the flip-up capability.  I changed to what is shown in the last 3 PICS.  I totally built this from parts I had in my bag of tricks.  Turns out it is much heavier than the VK system, but there is no give in this system.   Shown next are the separate components.

I had this adjustable stem I bought a long time ago.  It was intended for a mountain bike, but because it was adjustable it was adaptable for my purpose.  Because it is adjustable, it is not the lightest component.  I split it as can be seen and put a carbon tube between.  I then attached an aluminum piece to the upper part with the aluminum part sliding inside the carbon.  I then got a RANS handlebar (cut down) to complete the system.  Definitely not as light as the VK system, but stiff and rigid and works for me.

Showing some of the details of the built up bike, the first two PICS show the finished handlebar/tiller system.  The next shows the front boom.  The two straps that secure the front BB piece into the boom tube are robust and secure the system without any rotation.  They are also very light…..something I was not able to accomplish with my bikes.  The next PIC shows the front brake.  A Bacchetta-type pull down system is a necessity here.  There is ample clearance before interference of brake to front boom, enabling a tight turn around…..something I am not able to do with my lowracers.  All my upright buddies know when I am riding my lowracers I have the turning capability of an SR-71 (Blackbird Spy Plane) at cruise speed and altitude!  The next PIC shows the TerraCycle over/under idler.  Truly a beautiful product!  The last two PICS show the rear stays attaching the upper seat to the main frame, and the seat adjustment angle.  More work is necessary here!  It is not rigid enough for me.  My fix is to attach the two members to each other with round carbon tubing.  There is too much flexibility in the rear and I think increasing the torsional stiffness in the rear end will help with the rotational stiffness.  I put miles on this set-up…..perhaps nearly not enough, however.  I was not comfortable sitting that high or what I perceived as overall too much flexibility.  I attributed this to a number of factors: The boom was very long (I have an X-seam of 47 inches) and the fork length (26 inches vs. 20) made the front end flex too much for me.  Also the rear was flexy (previously mentioned).  Perhaps more time on the machine would have fixed that, but I wanted to try something else.  I surmised that my time on a lowracer with a small front wheel was the ultimate in front end rigidity (assuming the boom is also stiff).   My next experiment was to change out the front wheel to a 406 20 inch wheel and see how that works.

My decision is to keep experimenting, but my main ride continues to be my XPort.  I have approximately 6,000 miles on it and 5,200 were in 06.  It is as stiff a bike I ever had.  The front end does not rotate a bit even with hard mashing.  It is not as comfortable as my Baron Clone, but that is because of the front wheel drive system, and the fork rake.  The weight of the VKHi shown here is approximately 21 pounds.  I am, however, using a ROTOR system which weighs 1 pound more than a light weight crank. Also, I am using a tiller/handlebar system that is much heavier than the Velokraft supplied system.  It is very conceivable that this bike with all-around light components could come in at 19 pounds. 

Having said all that, my plan is to start with the existing frame and strip it, re-structure the failure and attachment points and cover it with carbon sleeves.  I will bond the nose piece to the boom and also the seat to the frame for added rigidity.  The last four PICS show the molds made for the BC.  The form started with a male two part plug, from which was then made a female too part female shell.  The last PIC shows the lid that was made because I filled the halves with expanding foam (again not recommended).  Since I do not want to start a new frame from scratch, I am willing to offer these mold to the HPV community for building purposes…..no charge…..except you pay the freight!  The only stipulation is that if there are numerous takers, you share with the next.  Please contact me if interested for particulars.  I also have a final frame jig for the final assembly for the assembly of the rear stays.  One step at a time!  I was going to destroy these molds for lack of storage, but perhaps they can be used for whatever purpose.  Next Time!