Sunday, March 24, 2013

First Ride of the Cruzigami Mantis

We got back Friday from Vermont and it was much warmer here in Connecticut.  No snow on the ground. Saturday I tried to go out for my maiden voyage with the Cruzigami Mantis, but that wasn't meant to be.  I hadn't done a great job of making sure everything was tight after unloading the bike from the car.  I pulled into a drive way about half a block from my house to tighten things where I learned a new way to destroy a brake cable.

Front triangle.  Red arrow points to the where I have the cables threaded and where I smooshed the rear brake cable.

Close up shot of where I pointed to in above picture.  Notice the silver bolt.  When the triangle is not attached, it is possible for a cable to get in between the bolt and the wall and it will get smooshed if one is not paying attention.

I had removed the stem and the triangle of the front of the bike to tighten the Delta stem riser.  When I put the front triangle back on, I wasn't paying attention and it got smooshed between the wall and the silver bolt above. The brake cables are lined with metal and when I crushed it, it grabbed hold of the brake cable, effectively freezing my rear brake.

This morning, I took the monkeys to the local REI and bought a new brake cable and housing as well as a shorter seat post (27.2 mm diameter for those with a Origami Mantis).  I got the cable and seat post installed (lowering the seat angle somewhat) this afternoon, pumped the tires up to 100 PSI and went off for a ride.

The ride went quite well; I am very pleased with how the bike rides. The bike feels very similar to my Cruzbike Sofrider - I can ride this one with no hands as well.  I have the two bikes geared almost identically with the same pedals.  I averaged just under 12 mph which is just a bit better than I've been doing recently on similar rides.

Towards the end of the ride, I heard a thump-thump-thump noise coming from the front.  I could tell something was off with the front wheel, but I was close to home and made it there without incident. When I got home, I realized the front tire is not doing well at all.

Picture of where the tire is falling apart.

In one area, the casing of the tire is starting to separate from the base.

Video of tire rotating.  You can see the bulge in the tire (watch it periodically obscure the "Kool" on the brake pade.  The bulge causes a thump-thump noise when riding.

As you can see from the above video, you can see a bulge when that area of the tire rotates around.  I don't have an explanation except manufacturing defect (I rode less than 1 mile on the tire before today where it was inflated to 50 PSI).  I'll report it to Schwalbe and see what they say.

A slightly disappointing end to my maiden voyage, although it would have been a lot worse if the tire had blown, so I think I'll consider myself lucky.  I'm very pleased with how the bike came together and how it handles on the road.

Me on the Cruzigami Mantis.

Thursday, March 21, 2013

Introducing the Cruzigami Mantis

I have taken this week off and Kate, the monkeys and I went up to her parents house.  I had been hoping to get some bicycle riding in, but we drove up during a blizzard and have gotten a foot of snow this week (it snowed in Connecticut, too).  So I haven't gotten any bicycle riding in, but I did get to put the finishing touches on something I've been working on for the last few months.

I'd like to introduce the World's First (and currently only) Cruzigami Mantis - a folding, full-suspension recumbent moving bottom bracket (MBB) forward wheel drive (FWD) bicycle.  The goal in building this bicycle was to (1) have a bicycle that can be packed into a single suitcase including wheels (hopefully more on this later)  and (2) have this bike not compromise on the ride.

The Cruzigami Mantis - After

The Origami Mantis - Before

This bike is a fully suspended folding Origami Mantis bicycle converted into a FWD recumbent with a Cruzbike conversion kit (which includes both the seat and the front triangle).  From the original bicycle, I kept the frame, the fork and the kick-stand (replacing everything else). I have plans to use original parts from the folding bike to completely rework a Greenzone folding bicycle that I rode into the ground.

For those who don't want to bother reading what I have below, here is a video:

The rear wheel is a  used (former front wheel)  Alexrimm with a Shimano Deore hub that I got used from 'Bent Rider Online ad.  It came with the (slightly used) Primo Comet tires shown.  

The rear wheel and rear suspension.  I removed a guard that was attached to protect the chainring when it was attached in it's original position.

I use Shimano Acera V-brakes for both front and rear and XLC alloy V-brake levers mounted on a Wald steel handlebars attached using the same Dimension adjustable stem I use on the Sofrider. A Mirricle bar-end mirror and locking grips finish off the cockpit. 

The handlebars with the XLC brakes, SRAM trigger shifters, and Mirricle mirror.  You might also notice the Garmin 305 mount on the stem.

On the front brakes, I use  Kool Stop brake pads.  To keep the trail of the converted bicycle reasonable, the front fork is turned around when the kit is mounted.

The Koolstop pads with Shimano Acela brakes and Marathon Kojak tires.

The drivetrain is a FSA Gossamer triple crank which came with 50/39/30T rings where I replaced the 30T with a Sugino 24T granny gear.  Like on my Sofrider, I use Nashbar Soho pedals (one side clipless, one side platform).  I use an SRAM X.9 (10 speed) front deraulleur (I should use a 9 speed, but this was available).

The FSA Gossamer triple crank with the Sugino granny gear, the SRAM X.9 front derailleur, and Nashbar Soho pedals.

The front wheel has a Capreo hub and a 9 speed 9T-26T cassette (that I bought from another 'Bent Rider Online ad) shifted with an SRAM X.4 9 speed rear derailleur.  I use SRAM X.7 trigger shifters for both front and rear derailleurs.

The SRAM X.4 rear derailleur mounted on the Cruzbike conversion kit mounts. I haven't yet trimmed the shifter cables.

To allow the bicycle to still fold, I use wing-nuts to secure the two halves of the seat together and the bottom half of the seat is mounted such that it does not interfere with the bicycle fold.

The seat is mounted on the front half of the frame and does not interfere with the folding of the bicycle.  The seat pieces are attached with wing-nuts so that I cat attach them by hand.

Cruzigami Mantis Gearing

The choice of the Capreo 9-26T cassette was chosen so that this Cruzigami Mantis bicycle is geared almost identically to my Cruzbike Sofrider.  The Mantis, with its 20" wheels is geared from 17.6 to 106 gear inches; the Sofrider and its 26" wheels, is geared from 16.8 to 107 gear inches (For reference: a 700c wheel with a 23mm tire and 50T chainring and 12T cog has 109 gear inches).

Cruzigami Mantis Gearing (with 20" wheels)- the top (big ring), middle (middle ring) and bottom (granny gear) speeds for a cadence between 75 to 110 RPM.  Picture a snapshot of Mike Sherman's gear page.

 Cruzbike Sofrider (with 26" wheels) - the top (big ring)middle (middle ring) and bottom (granny gear) speeds for a cadence between 75 to 110 RPM.

The gearing and the tires were chosen to give this bike a ride as similar to a big wheeled bike as possible.

As you can see, although the bike still folds, it isn't nearly as convenient as it was in its original form.  The ultimate goal of this bicycle is to have it be packable (with the wheels) in a single airline-legal suitcase (hopefully more on this later).

Now that I finally have the bicycle assembled, now I'm just waiting for, well, roads that aren't completely covered in snow to try it out. Hopefully not too much longer and I'll be able to provide my first impressions of how it handles.

Threadless Fork

Unlike most folders I've seen, the Origami Mantis comes with a threadless fork (like modern road bikes).  As can be seen by the picture below, there is not a lot of stem sticking above the fork, so that it was difficult for the Cruzbike kit to grab a hold of it.. To solve this, I use Delta stem raiser that both attaches to the star nut inside and grabs onto the fork.  It's also works well in that I can remove the stem from the Cruzbike kit without having the fork fall off (will be useful for packing).

(It makes sense that the amount of the fork above the frame is so short because there is usually a foldable stem.  It just isn't ideal for this application.)

Threadless fork of the Origami Mantis and a view of the star nut inside.

Bike Folded:

Here are some pictures of the bike folded in the back of our mini-van.  None of these are fantastic pictures, but they do (pretty much) show what's going on.  Here is the complete bike except the seat back (and post) are removed.

Everything is folded except the stem.

Side view

Close up.

How to build a Cruzbike conversion - in 90 seconds

A lot of people are curious how to do a Cruzbike conversion.  Here's a video that I had nothing to do with (except encouraging Brian to make and post it).  It is a very cool time-elapse video that shows in 90 seconds how a conversion is put together:

Bryan's How to Build a Cruzbike Conversion in 90 seconds video