Tuesday, February 26, 2008

No weld crank forward conversion part 2

Here is the other part of my mtb to CF confersion. Have about 10" riser under a pair of truncated 44cm wide drop bars. A quick test ride (of about 17 seconds) out in the dark street at 25 degrees f. shows the bike may have real promise as a comfort bike. Not nearly as laid back as CF2 or CF1 (farther down this page) but it has much more relaxed feel than the old mtb had and a person can easily stand on the pedals if one wishes to do so. Obviously, more testing is in order. One improvement I could make is in the steering riser as it is a very heavy part and could be redone in thin wall Cr-mo to knock off a pound or 2.

No weld crank forward conversion from mountain bike

Here is my old Schwinn High Sierra mountain bike. (I know, the drop bars look more like road bike....) This bike has been mostly collecting dust since I started building and riding recumbent and crank forward bikes. I plan to try making a sort of crank forward bike out of this by putting a big fat C.F. style saddle back about 5" from the current location.

Here is the old saddle and the new seat pan.

Here is the new seat with struts supporting the back portion.

Here is how the back part of this conversion will look. The seat can be adjusted for height with the quick release lever as usual at the base of the seat post. The struts supporting the back of the seat have holes drilled through which hairpin type clips are used to adjust the tilt angle.

The next step is to bring the handle bars up higher and farther back for easier reach. Stay tuned...

Tuesday, February 5, 2008

Tweaking crank forward #1

My first crank forward and only folding (or should I say collapsable?) bike had a road fork and a 26x1.75" tire up front with a 26x2" in back. One of the junk bikes in the basement had a nice fat mountain bike fork so I painted that and replaced the skinny road fork and the medium sized tire with the wide fork and a nice fat tire. I liked the new arrangement so well I started thinking I might put a triple crank (22 32 42) on this bike and give it even better off road ability. The rear brake cable and rear derailler cable on this bike have home built disconnects for when the frame is spit in two for transporting so I made up another disconnect for the front derailler when it is added. Here are a picture of the pieces and of the cable as connected.

Sunday, February 3, 2008

Long Wheelbase or short?

When I first started building and riding recumbent bikes I thought short wheelbase was the way to go. Short wheelbase bikes are easier to transport and have much quicker steering response. But I was curious about claims of more comfort and better positioning for hill climbing on long wheelbase recumbents and decided to build recumbent number 3 as a LWB.
Number 3 is the blue bike above. I liked the ride of the LWB almost immediately. Very easy learning curve and I felt like it was more comfortable and easier to master hills with. Number 3 was made from an old Schwinn hi-tensile steel bike and some electrical conduit (not real high tech stuff) but I was ready to part with my entire short wheelbase fleet of 3 bikes within a few months. I decided to build number 4 (shown above right) using the same basic Tour Easy design http://www.recumbents.com/wisil/plans/plans1.htm but using a Cro-moly Schwinn World Sport ($5 from a neighbor's garage sale) and good thinwall Cro-moly tubing from the local aircraft supply store. Number 4 was a good 4 lbs lighter than number 3 and is a wonderful touring machine. I kept number 4 for several years until number 11 proved to be a fit replacement. A friend now owns number 4 and still rides it on the streets of Kansas City.

Saturday, February 2, 2008

This is where I started this bike building stuff back in 1998 with home built short wheelbase 26x20 recumbent--sort of a muffler pipe version of a Rans V-rex. http://www.ransbikes.com/VREX07.htm This bike was pretty heavy but tracked very well right from the start. I had never ridden a recumbent more than across a bike shop parking lot when this bike was completed so I learned to ride a recumbent while testing this bike. It was almost as much fun as learing to ride my first bike at age 6 but without the harsh landing in a pear tree this time!

Within a few months I started build my second recumbent, this time a 20x20 short wheelbase model. This one used a BMX bike as a starting point with a little muffler pipe brazed onto the head tube for the crank to mount on. The crankset is mounted on a sliding tube that fits over the boom that is attached to the head tube. This bike was lighter the the first one I built and also handled quite well but was a bit short in the wheelbase so that a large bump encountered going up a steep hill could result in lofting the front wheel skyward. I felt like this was about as good as I was going to get with the short wheelbase design and bought a factory built Rans Rocket next. http://www.ransbikes.com/Rocket07.htm

Friday, February 1, 2008

Searching for better bicycle designs

Here are some bikes I've built from parts of existing bikes. I started with a short wheelbase recumbent and eventually built 13 recumbent bikes and a couple of crank forward bikes.

This is my current favorite touring bike--my 11th homebuilt recumbent. It is sort of an Easy Racers Tour Easy clone. It has a 27" rear wheel and a 406 type 20" front and a 2 x 7 derailler transmission. This bike started life as a Centurian road bike my neighbor donated and is very smooth and comfortable. I built a couple of long wheelbase recumbents since this one for other people but I feel like this one represents about the best I can do for now with existing methods and materials I can comfortably work with.

My latest projects have been home built crank forward bikes.

My first c.f. was made frome and old Araya road bike and pieces of a Performance road bike. I decided to make it a collapsible bike after I had it in rideable form. Here are pictures of it:

This bike fits into the trunk of my Hyundai Elantra very nicely once I break the frame in two sections and pull the seat and front wheel.

My second effort at home built crank forward involved an old Schwinn LeTour and I laid the seat post farther back and angled the head tube back to about 60 degrees to improve steering response:

Here is CF #2 on the brazing jig. The seat tube and long sections of chain stays are new 4130 cro-mo tubing from AirParts here in Kansas City. http://www.airpartsinc.com/

Here is a look at the seat pan in construcion and a shot of the finished bike. It is very comfortable but not very fast down hill or into the wind compared to a recumbent but is ideal for short trips to the store etc.