mrv 

Howdy
I don't have anything helpful to add (and I never let that stop me), but related to this subject, I just (nearly) finished putting together this Franken-single speed.
The frame is an old Raleigh from I don't know when, the fork is off a Cherry custom frame that I had to retire due to corrosion.
I was concerned about what the steering dynamics might be like when I started cobbling everything together. It steers a bit different than any other bike I've ridden. From reading the previous posts, I'm thinking the straight fork is giving a short trail dimension. The bike seems to "want" to stay centered, but once I steer off center, it feels like it wants to "dive" into a turn. I'm running the fattest tires the fork will accept (700c X 28).

Does that make sense? Is that what I'm experiencing on the bike? A short trail?
Any comments, criticisms, or ridiculing is appreciated.

@FarHorizon: As far as riding no hands all the time - are you thinking of doing something like this: https://www.youtube.com/watch?v=0Rw3q32oPCk

FarHorizon

Howdy, @mrv -

I think you may have too MUCH trail, based on your description. But I could be wrong...

As to "no hands" riding, I do it ONLY on long stretches of straight road when there is NO traffic. The variety of positions (including no-hands) keeps my bootie from getting sore.

Andrew R Stewart 

It's not hard to measure what the trail is of an actual bike. A method to hold the bike vertical and the fork straight, a carpenter's square placed on the floor and bisecting the axle then a straight edge (meter stick?) placed along the head tube/headset. As I commented in another thread about guessing the frame's rear spacing, one measurement is worth more then an infinite guesses. Andy.

unterhausen

as mrv's post demonstrates, trail certainly isn't the only interesting thing about bicycle steering. It sounds as if the frankenbike has a lot of wheel flop. A lot of slack head angle bikes have a lot of flop, it can be annoying when wheeling them around in the shop

79pmooney

FarHorizon, did you part with that racing bike you loved so much? If you still have it, a good framebuilder ought to be able to take measurements off it and create a bike that steers similarly but accommodates the changes you want.

I did this with my 1st custom ti bike. I chanced on a Univega racing from the mid '80s that fit and steered wonderfully. Not a practical bike and it was a lesser model and the frame was heavy and stiff. I took it to TiCycles and said that I wanted that steering feel, a longer top tube so I could go 12 cm on the stem and higher BB (I hit those Univega pedals all the time).

My ti fixie came about in similar fashion. I had a cobbled together fixie that was a blast to ride. Measured it up and drew it up (in a CAD program on the computer), tweaked it a little, raised the BB a lot and now have a sweet fixie that can do any ride and is both a blast and joy to ride.

I now have a "database" in my CAD program with most of the bikes I have owned drawn up and placed on different "layers" so I can look at any of them singly or superimpose any bike on any other. All bikes are drawn around the BB, so fit changes are readily obvious. The same thing could be done with paper, using translucent drafting paper or film, drawing the bikes full size (or say half size) and viewing them on a light table or perhaps hung in front of a sunlit picture window.

So my quick take? Don't let good rides escape undocumented! (Best do it now; it may be very hard to get good measurements after a crash.)

Ben

FarHorizon

Sorry, Ben, I parted it out on eBay long, long ago. If I ever find another bike that fits that well, I'll do EXACTLY what you recommend. I could go around the local bike shops, taking "test rides" until I found a model that fit (and then look online for the measurements), but it hardly seems fair to the local shops... If new bikes weren't so darned expensive now, I'd just buy one that fit, but I'm an inherent cheapskate.

So my "plan B" is to buy every yard sale bike I find that even remotely fits, try them out, and keep the one that fits the best. The remainder, I'll donate to the local co-op that gives free bikes to needy kids. It's a win-win plan, and I'll get to try LOTS of bikes for not much $$.

ksisler

Far; 5 Ditto's here. A nicely done butted steel frame with 71.5 or 72 degree ST and HT angles makes a great riding bike. I have loaned out several of mine over the years or many occasions when folks bring in their "racer bikes" for lots of equipment changes to make them more ride-able.

/K