CRUZBIKE Sigma

[`PhillyJoe]

This evening I decided to get reacquainted with the assembly of my Quest, and to my surprise I found a You Tube video on a long- wheel based CRUZBIKE model called Sigma. Well, needless to say I almost fainted, as I was overwhelmed and entered a stage of pure ecstasy. The bike is beautiful!

It featured disc brakes with a 26-inch rear wheel and a smaller 20-inch front wheel. The frame design is other-worldly, reminiscent of bikes formerly made in Freedom, California, but on steroids. And it has rear drive. Yes, I'm not kidding. Has anyone personally experienced this bike?

P.S. - Surely, I'll dream about this bike tonight.

 

[Frito Bandito]

You are right about that Joe. What a gorgeous CB! Other than it being a bit tall, I have a small project going on that the Sigma looks about perfect for.

 

[Mathew Fy]

They didn’t sell many of those. I’ve heard its handling characteristics are not good.
I think Larry has one for his “Cruseum”, it may have been the last one Cruzbike sold.

 

[ratz]

Yeah it was the fast fall bike. history is so cool

 

[LarryOz]

They didn’t sell many of those. I’ve heard its handling characteristics are not good.
I think Larry has one for his “Cruseum”, it may have been the last one Cruzbike sold.

Yes, quite an interesting piece of Cruzbike History. I think it had a few design flaws - but I'll let @doughburton fill us in on those as he is the expert

Unfortunately this is still one I am looking for - but hopefully one will turn up for me.

 

[Robert Holler]

Yes, quite an interesting piece of Cruzbike History. I think it had a few design flaws - but I'll let @doughburton fill us in on those as he is the expert

Unfortunately this is still one I am looking for - but hopefully one will turn up for me.

Larry - contact me in my email.

 

[Doug Burton]

Yeah, I have a LOT of experience with this bike. The production run was 15 bikes.

It is indeed beautiful to look at.

But after a LOT of work trying to rectify its handling and steering behavior, it beat me.

It was hard to keep on a straight line, and the single u-joint steering caused a non-linear relationship between how much you turned the handlebars and how far the front wheel turned. That, combined with a significant amount of trail, made it pretty tough to adapt to.

Being that the head tube angle was 61 degrees, like a Tour Easy, I figured I'd try setting the front end up like a Tour Easy to see if there was any positive change in things. After fabricating a fork with more rake (ala Tour Easy) I still couldn't get past the angular turn differential. So I built it again using an additional u-joint, which should have cancelled out the angular acceleration effect, but the resulting orientation of the handlebar interfered with everything. Knees, thighs, etc. And it was super un-natural to steer.

Sometimes I think there's no such thing as a lost cause. Then I get properly humbled.

Yeah, I have experience with it...

 

[3bs]

my head hurts just looking at the thing

 

[Opik]

I still wonder how Mochett got his U joint right and had Faure broke records

 

[Tuloose]

One has to wonder why John Tolhurst (I think I remember seeing a video of him promoting the Sigma) would want to add a RWD recumbent to the Cruzbike line?
Wouldn't that dilute the brand?
FWD, MBB is what sets Cruzbikes apart from all the other the recumbents out there.
Why come out with an inferior product just to add a RWD to the stable?
Good riddance I say!

 

[Robert Holler]

The Sigma was a special build he did for a friend of his but I am not sure of all the exact history. Indeed it does not add to the brand (or to recumbents as far as moving them forward in a positive direction). It was and is not a good bike. As a museum piece of "what not to do" it is a great addition, however.

 

[Tuloose]

The Sigma was a special build he did for a friend of his but I am not sure of all the exact history. Indeed it does not add to the brand (or to recumbents as far as moving them forward in a positive direction). It was and is not a good bike. As a museum piece of "what not to do" it is a great addition, however.

Thanks for the explanation Robert.
I was wondering why they would bring out a LWB recumbent when Rans and Easy Racers had already perfected the genre.
And Doug, I didn't mean to disparage in any way your efforts to make the Sigma road worthy.

 

[LarryOz]

So excited, just recieved a Sigma for the Cruzeum, still in it;s original box from 2009!
Cruzbike has graciously donated it to the Museum! Thanks so much Robert for gettig that ball rolling.
Tomorrow I will upack it and attempt to put it together - and then find some place of honor for it!

 

[Bill Wightman]

Maybe this incarnation is the "perpetual motion" equivalent of bikes but it does have some intriguing design features. The chain is long but efficient, the seat could drop down to the lower strut to make it more of a bent stick bike, the steering could be converted to a tensile cable-over-rollers system. I find it interesting because you can conceptually radically lower the seat, move the steering pivot angle and location anywhere, and it becomes an efficient two-wheel platform for a long fairing streamliner if you are into that kind of thing. Have to understand basic bicycle stability concept better, "can you coast with your hands off the handlebars thing". Food for thought. Not a Cruzbike for sure, but fodder for bike designs and modelling. Might start looking like a long low V20 with conventional steering pivot and BB, but strange steering linkage. Might get heavy.

 

[LarryOz]

The Cruzbike Sigma is finally assembled and bike #31 in Cruzeum.
Worked on and off for parts of 3 days. It took me longer to put this one Sigma together than it did to put all 4 of the newest Cruzbikes together.
From what I have read they only make a single batch of 25 (or 15 depeding on who to ask). There was a lot of sanding and scraping paint of of mating surfaces, filing mounting brackets, just trying to figure out where all the part went, etc. Nothing was "pre-assembled" as we are used to now. Plus with no real instructions and lots of "un-unsed parts". John T did make a couple 10 -min videos (about 14 years ago or so) but he put together one that was basically 2 or 3 pre-assembed parts. Mine was not. Everything from mounting the seat bracket, to internally running cables, installing BB and cranks, mounting and connecting the disc brakes, monting an hooking up a SRAM i-motion 9 internal hub (which I also could not find any directions on - even online!

Here she is: - and if I look a little crazy - well, now you know why!

I even took her for a spin around the block - and survived, sortof! - Kind of reminded me of back when I was 13 and I had one of those Stingray bikes with the front forks swooping way out the front - although those were not scary to ride. Sigma was ok, really, at least once I got going - and did not have to worry about turning. haha Then it got a little scarey. I can see why it was not a big seller - But she'll make a nice conversation piece in the Cruzeum.


Here is the Sigma leaning up against the 4 latest versions of Cruzbikes.


This was an intersting lable on the seat: Instead of "Cruzbike", it says "Engima" - Seems apropos!





And this even better: The "question mark" stamped into the metal bracket of the seatstay! I put some white paper behind it so it would stand out


Left over parts - I usually have 1 or 2 pieces I am curious about - I think this is a record!

 

[Tuloose]

Way to go Larry.
You are a true and dedicated Cruzbiker.

 

[Robert Holler]

The "?" on the back says everything and it is my favorite part of the Sigma.

Congrats on the build. I have built 2 of them from the same state I sent yours. You can now claim to have passed the assembly gauntlet/ninja challenge.

 

[ratz]

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