Luke's new race bike 1-week build thread.

I'm building a new bike for this Willow springs race June 18th.

I ordered $660usd in CroMo tubing in various sizes last night.
My friend Paul ordered some various bending/jigging/clamping tools for frame building and a new welding table.

The motor came today, hand delivered by its creator, who is a VERY awesomely smart guy. Thank you Diederik!


The frame will be rigid rear, possibly sprung front, if and only if I can find a fork with an extremely stiff dampening rate, extremely rigid bodies and crown, and just a couple inches of suspension at the most. IMHO, 99.9% of suspension forks on bikes racing a kart track are going to be a big hinderer to riding rather than a help.

Brake will be dirtbike based this time rather than the Hayse stroker ace downhill brakes on 8.5" rotors that I used last time, which faded something awful at the death race, and regularly boil and warp rotors on the pink bike. Brakes are extremely important road racing, having something you know wont fade gives you the confidence to commit to corner entry speeds you wouldn't otherwise try. I would like to get the Brembo setup off a KTM if possible. Might just take the brake setup off one of my KTM's and borrow it for this bike.

So, step one to any build is sourcing and deciding on the pieces that will best work together, and step 2 is making all the custom parts and systems to attach them together and make them play well. I'm exiting phase 1 at this point, and excited to get going on phase 2 this weekend.


So, now I've got to find a decent controller for my motor... So, let's measure the resistance and see what ball-park we're in for controller loading.




So, you will notice on that sexy sexy 6.5digit ethernet linked Kethley DMM and the Sorensen 8-125 power supply current set to 50amps, we have a phase winding resistance of ~50mOhm. The motor has a KV of 28. This basically means it won't be straining any controller, but it will need some voltage to get it up to speed, so let's see what we have for controllers in the 120v area.

Hmm... Hmm... so many to choose from! What to pick! What to pick! Since I'm not going to be running more than 10hp (as agreed with the fellow hosting this event), I think I will go with the baby size#2 sevcon, which will be just about right for my modest power needs here.




Now we need a ~120v battery... something pretty light and stiff, with plenty of capacity.

Ahh, yes, here we go, didn't even have to get out of my chair to reach a compact little pack that will suit my needs.




So, now it's time for a little CADoodling to design a sprocket adapter for this fantastic motor that was built to mount a prop, and time to begin picking suitable frame geometry.



Here are some pics of the hall placement. This is absolutely perfect placement.

However... then we were spinning the rotor and experimenting with pushing the halls closer and further from the rotor to try to get the dutycycle as close to 50% as possible, and pushed it into the rotor and tore a couple of the sensors off... D'oh! Now I gotta re-do it.

Here we have the re-done halls. Not pretty this time, but also not ripped off from hitting the rotor. lol



Motor spinning FTW. This thing makes stupid torque! At like 5rpm and the lowest throttle setting you can't stop it with your hand.



The little ~20awg aligator clip tester phase lead didn't like even handling the no-load current much... lol

I didn't take as many pics as I should have, but here's some progress update pics.


The sprocket we made got sharpied into something more offensive to the British guy. Don't want to leave out offending everyone. :mrgreen:


Earlier in the week, we made 3 electric go-karts using perm132 motors. The 3 karts were just craigslist cheapo karts with blown or missing engines, the perms and controllers and batts were just stuff we had laying around, the batts just mounted by rachet straps. lol Rallying around with 3 karts was a blast on Sunday though. I drifted my bro's kart until the rear tire shreaded and blew, and it's on video.

Then, my fast shipping on the 4130 DOM cro-mo tubing arrived! Hooray! Yes, that's a lot of cro-mo tubing!



The workshop for metal fab. (my bro Paul's garage)


I drew doodles for 5 minutes.




Then when we had a very crude idea, we moved to solidworks.

Then we cut tubing and started making the notches with a holesaw in the mill.



But... we couldn't find all of the sizes we needed in hole saws... so we busted out a boring bar, spun it in there, got the cut finished, and then BAM!!! Obliterated the boring bar right as it finished the cut. Perfect! Notice the nice bend in it? lol


Next was laying it out to get jiggy and TIGgy with it. But it was 3AM on a sunday in the driveway of a neighborhood... so we just called it a night, and tonight we will hopefully finish cutting the tubes for the back of the frame and motor mount system and TIG'ing it all up nice and neat.

So, frame is STILL not finished, nor have we even started the welding of the current design revision. (changed because we are not going to use the Joby motor)

This my first bike frame build entirely from scratch, and it seems a few things are different than I expected.
The time and effort break-down goes something like this.


Design: 2% time 1% effort
Sourcing materials: 0.1% time 0.1% effort
Cutting all the compound angle miters on the tubes so they fit together perfect: 85% time 95% effort
Jigging and welding it together 14% time, 4% effort.












This is the state of things right now. We crossed the 100 man-hours of labor in the build mark last night. It's taking longer than I had expected, but it's also turning out better than I expected as well. The build is just for this single event though, so we need to push-through on pouring as work as possible to get it done by Friday night or it's all for not.

Also, the fasteners in that brake caliper mount are just dummy fasteners to help us get the position while making the brackets etc. The real fasteners will obviously be the right length and torqued/loc-tited down. lol

After I finish my shift at work today, we've gotta haul ass to the shop and finish the bike, pack it up, and drive down to the Willow Springs even on the 18th! (tomorrow morning it starts!)


We've still gotta finish the rear-stay assembly/jigging/welding, the motor welding, the controller and battery mounting, then we can pile it in the car and I will wire it all up on the 6hour drive down to the racetrack.

Bike is done. It rips. Really turned out nice. Frame is beautiful



We are driving to willow springs now. 5Hrs left in the drive. ETA 11am.

Wall thickness is 0.045, 0.035, and 0.065 in various places depending on which were the most strength critical.


Here is a video of the completed bike!

YouTube - ‪newebike‬‏


This damage is from the pack bouncing out and rubbing on the tire until it wore a hole through it right into the foils!

This is like the 4th working-till-3AM night in a row for me... I was falling asleep inbetween being the throttle man on the dyno... LOL!



I got her dialed in and made it to Laguna Seca!!!

Won 3rd place!!! Woot!!!

This was our race team of buddies, our team dominated! Each of those bikes you see was a bike I had a hand in helping put together, and many of those guys had a hand in helping get my bike together and dialed in.

harry76 said:

I noticed in the pictures you cut all the cro-mo so the joins were perfect. But i notice the rear triangle is very crude..... did you run out of time or is that the finished product? Just wondering

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As of 4AM the night before the race we had to leave the house by 7AM to make, the rear of the bike didn't even exist... It was just sketches of how it needed to be, as we had 3 separate motor choice changes during this build, each one needing a different rear section to work. So yeah, the rear section was rushed. lol

happyvalley said:

Pretty impressive work. I see the word 'build' tossed around, a lot of people assemble bikes but you are building them.

BTW, how the heck did you get Cedric Lynch on your team?

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This was just amazing luck! Cedric was around for some business reasons, and had seen my hill-climb dominating e-bike that featured his motor, along with some of my earlier work and wanted to help out!!

Cedric is like God's gift to building bad-ass motors, I learned a ton from him, and he was a super nice guy.