technogym bike

INDOOR BIKE TRAINER

(MARCH TO DECEMBER 2006)

JOB SUPER DONE , MAN

I had a chance to get an old bike Xt out of a gym sale and I decided to make few improvements on "her" to make she fit to my needs. First of all I planned to repaint the bike and install my old pedals SPD (shimano) to use my enduro mtb shoes.. After few weeks I understood that the pedal thread of the original crankset is 1/2" that is different to the 9/16" used for all the mountain bike professional pedals.... So, that was my first problem: How to mount my old SPD onto a different crankset.?? I did not planned more modifications on the bike, but day by day I started dreaming a perfect indoor trainer.

All this things happened before the creation of the workshop, and the need to make parts to customize this old bike xt is the thing that pushed me to create the workshop! I always dreamt a workshop with lathe and mill in the last 5 - 10 years, and I thought : "why wait more years to make dreams true ??"

Decision was taken: the workshop is gonna exist soon!!

I had to stop thinking about the bike xt for about 3 months, just the time to make the workshop running, but once the workshop was made the entire project of the indoor trainer become more giant!!

Yes, my target was to make a similar indoor trainer as my real ENDURO bike, this means same crankset length, same handlebar, same saddle, and last but most important same geometry, to pedal on the same platform as the reality.

above the real one and the project of the indoor trainer and below the old indoor trainer bought ....

the state of the old bike was quite bad. The bike was rusty everywhere and many components were bad.

....let's start working...

First step of the whole project was to break down the bike ready to cut the unwanted old handlebar/cockpit assembly..

the band saw had its first task.!!

I had to turn the frame to complete the cut....it is not so easy to hold a 40 kg iron frame into a band saw!! I had to make a stand using few boxes and many spacers (one of those was a toothbrush!!)

let's go with the first base coats....the frame were all sanded down to remove the rust if present and then a primer/antirust coat was sprayed.

after that, the top coat in blue (subaru blue) was sprayed only on the high external part of the frame, only because each spray can costs me 14 pounds !!!

the two bases were painted in matt black

To solve the problem of mounting a new crankset into a different hub I had to make two adapters.

The job start centering the aluminum piece on the 4 jaw chuck

...making the center hole..

then drilling up to 23 mm.... ( a long step by step procedure...)

third photos shows how necessary is a 550 mm lathe bed, if you plan to use 23 or more mm drill bits!!

...to finish exactly at 24.00mm the adapter few passes of internal boring are required...

now it is turn of machining the outside...

one cut with the handsaw and two passes to flatten the sides edges..

voilà (repeat all for the second spacer!!) parts are ready.

the chaining need to few machining steps to work with the new crankset mounting holes....

first of all a drill in the center... at 24mm...

then, after a draw on the surface of the PCB holes, I have done 4 * 8 mm Each holes..

right, the chainring is ready to be painted now, the paper tape is placed on the teeth to protect them from the paint..

voilà, few coats of subaru blue and the chainring is ready!! ( photo shows the "intelligent" way to heat up the paint-job as drying time!)

the chainring is installed ! looks good!!

alternator, chain, pedals, freewheel rim are installed too...

ok, I am doing a good job, but if I want to use the bike I need handlebar!!

The original one were cut and bin in one of steps above, now I need to create a STEM to hold in place the new downhill handlebar got on ebay for 5 quids..!!!

raw material for the stem is a aluminum block (sizes written on it !)

one cut with the band saw to get the length of 145.... then, trueing surfaces with Seco Octomill... 6 sides..

the piece is mounted on the lathe using only three of the 4 jaws... part was spinning 1,5 mm from the bed ways!! photo shows center drilling step...

then, from 6mm to 24 many steps were repeated to get a 24mm hole...

and as always , a internal boring action is needed to get desired inner diameter...

first hole is made, now it is time to position the part on the mill to make the second one, that is 24.00 mm (this means I can use normal blacksmith drills, and no lathe boring is required for this second hole..)

centering (above) and last step of a long step by step drilling action.. (below)

to make an incline surface to hold the cockpit I tried to use an end mill but after few passes the part comes off the vice and I had the bad result showed below.... at that point I understood that a cut with the band saw is faster and safer...

..but must be finished with the octomill - surface mill.

to attach the cockpit on the stem I though to make two M10 threads... (showed the making of one)

To tight the handlebars 6 holes were needed.... the photo shows making of the last one... 6mm drill bit

I do not trust M6 bolts screwed into the aluminum so I chose to use bolts/nuts. The nut side is machined to get the bolt INTO the stem body (I do not like things that comes off from the main body.. clean style!)

more machining to make space for pliers (to tight the bolts !)

end of the job is a countersink action on all sides and a refinish with the face mill..

ops.. I wrote the wrong thing... the job must continue. I need to detach the top part of the handle bar clamp to allow the handlebar to be positioned... (because it is a raise bar)

now the part is finished...