The Holy Grail Project

[Justin LE]

Originally Posted by Dartmech

Over the years I've been a member of multiple car and motorcycle forums that have never had a post with such detail and commitment to the final product. Kudos my friend. Oh the world domination devices I would make with all that machinery at my finger tips...
BUT it looks like its going to be ridiculously heavy. I still wanna ride when you get done though.

Oh, it's heavy that's for sure! Heavier than a lot of bicycles even. I'm leaving in about 4 hours on a train ride to SF for the weekend, so I might not have time to get many more build posts in before the middle of next week.

However, if anyone wants to brave riding it during this time, it will be meandering around the Maker Faire in San Mateo on both Saturday and Sunday. Well, odd's are with these things it will probably be broken by day 2 but hopefully we'll get to have some fun with it before that happens!

Maiden voyage was last Friday at the Kris Holm Book release party, and I was a little shaky on it. But we've since got the hang of things pretty well and Pinefresh really showed us how it's ridden at the vanuni wednesday meetup yesterday.

[Justin LE]

Originally Posted by scott ttocs

I did not realize you could braze stainless steel. Do you need special brazing rods?

It's not stainless, just standard DOM steel tubing. That said though, I'm pretty sure there are no issues brazing stainless with normal rods and fluxes.

[turtle]

crazy, great, very cool!

the frame looks really very nice, and i like the way you're trying new stuff and bring our sport further! we need people who have ideas and even go for it, thanks for that!

[MadFurai]

What else to say but insanely awesome.. Please keep us updated with any future developments or projects. If you ever bring it to the East Coast, let me know. I want to ride it!

[MuniOrBust]

This is an awesome accomplishment! Thanks for taking the time to post everything to share with the uni community.

So the shifter is under the saddle? I don't see it in any pics so far.

[jtrops]

That is a beautiful machine. Your fillets look perfect.

The one thing I don't like about the Nuvinci is the twist shifter. If you come up with a lever style shifter I'd love to see it. I have an idea to make a geared shifter since it needs to wrap something like 10" of cable altogether. Also, I think a lever would be easier to use on a uni.

[maestro8]

In a world full of square edges, the curves on your frame are a thing of beauty.

Thanks for sharing!

[pinefresh]

Thanks as always for giving me the chance to break your creations Justin.

Originally Posted by MuniOrBust

So the shifter is under the saddle? I don't see it in any pics so far.

At this point the shifter is the grey knob on the right side of the nuvinci. (see the second picture of me). I managed to shift on the fly, but it involved doubling over completely at the waist and reaching down, it was very awkward.

I'll make a post with my initial impressions if I have time after work, when I'm not on my phone.

[jtrops]

If I understand it correctly there should be very little backlash in this setup. Maybe a bit from chain looseness, but the sprague should engage almost instantly.

How is the transition from being geared up/down going forward to the 1:1 in reverse?

[corbin]

Awesome! I can't wait to see Justin tomorrow and ride it

Jason, you should come to the maker faire!!

corbin

[aracer]

Awesome - so glad to see you made this and impressed at how professional it looks. I just wish I had the sort of engineering facilities you have.

Can you just confirm for me - from previous discussions on this the clutch just allows you to apply back pressure on the pedals, you can't ride backwards, idle or rollback mount without things locking up? Is the engagement fast enough that it would be a problem if you sometimes have a very slight rollback as part of your static mount?

[Justin LE]

Hey everyone, just en route back from the Maker Faire where the nuvinci unicycle caused no casualties to riders, spectators, or itself! Actually, there weren't all that many takers to try riding it but Corbin sure knows how to make it look easy.

Originally Posted by jtrops

If I understand it correctly there should be very little backlash in this setup. Maybe a bit from chain looseness, but the sprague should engage almost instantly.

Correct. The sprague clutch does a brilliant job of taking up all backlash and with the chain taught there was none of the pedal play that caused a bit of an issue with the S3X build. So a bit +1 on that front.

How is the transition from being geared up/down going forward to the 1:1 in reverse?

This, on the other hand, is a bit trick to get used to! At the moment, the chain is geared 34:18 from cranks to the nuvinci, then 28:20 from nuvinci to the hub, or 2.64:1 overall, which equates to an equivalent 64 inch wheel when the nuvinci is in 1:1 mode.

When starting off with nuvinci in easiest gear at 0.5, we have equivalent to a 32 inch wheel rolling forwards and 64 inch when trying to brake, and almost everyone comes off when they hit the 64 inch wheel size trying to slow down.

With a bit of practice you get the hang OK but I was still never that comfortable at low speeds. As the nuvinci is geared up then the fwd/rev torque ratios become closer and this is less of an issue.

[jogi]

great iengineering you do!
also best building thread here!

[giocologgi]

WOW!
I'm not an expert, welll... I'm more noob than a noob in mechanics but... You rock!
Great work and thank you for sharing!

[maestro8]

Originally Posted by Justin LE

Corbin sure knows how to make it look easy

I've said it before and I'll say it again. Corbin is a robot overlord sent from the future to unicycle us all into submission.

Chuck is the John Connor sent to destroy Corbin.