Bike Machinery Hydra and BikeCad Pro

[Vincent la bricole]

Hello everyone,
this is my first post here after having spent a while reading the free encyplopedia this forum represents. Thank you to all the knowledge-sowers here!

I currently (this is my sixth year) work in The Netherlands, at a bike shop with a Bike Machinery Hydra jig and BikeCad Pro.


I am building a frame for myself, to get to know the hydra. i desiged the frame in BikeCad Pro, which gives me a X value of 526 and a Y value of 276 for the head tube- bottom distance.
I have troubles setting the hydra with the "Bike Machinery X" and "Bike Machinery Y" values provided by BikeCad. There seems to be a calculation step to use to be able to use these values to adjust the jig, but i do not get it.

The jig is third hand and I have no manual to refer to.

I set the head angles, bb drop, seat tube angle, chainstay length on the jig but it seems like a good idea to get the head tube on the right spot!

Any BikeCad and hydra users willing to help?

Thank you in advance!

Vincent Cretin.

PS: I also posted this on Bikecad.ca but thought it would be wise to ask here too.

[JFW]

Hi Vincent,

First of all I'll refer to this thread on the framebuilders-email list from a few years back: http://search.bikelist.org/beta/View...aspx?id=445066. Then (referring to your posting on bikecad.ca) I'll explain the scales briefly. You have the Y scale at the bottom of the whole front center frame assembly. That's where you use the Y measurement from Bikecad.

Then at the base-plate of the jig above the Y measurement you have the horizontal X measurement, but that's the front center X-measurement. In other words: the _horizontal_ X-measurement from the BB to the front hub. Thus you should use the data given from the "Front Center horizontal" measurement in Bikecad - NOT the "Bike Machinery X" (unless this have been corrected recently - I will have to check the latest Bikecad on my other computer later). Given that you've set up the front assembly of the Hydra correctly (ref. your bikecad.ca posting: the two scales at the far left top of the image). The fork measurements needs to be set with the correct rake of the fork you're going to use/make, as well as the correct length of the fork including the lower headset cup.

Here's a scan of the Hydra spec-sheet for dimensions: https://m.flickr.com/#/photos/planetjohnsen/8190109974/

Given that you have all of this done, it should give you a correct setup of the jig.

Did this make sense?

Truls