Fork height, trail, and rake questions

Just in case anyone is seriously interested in calculating fork rake, which is measured in mm, not degrees, some beardie old men cover it at length here... http://forum.ctc.org.uk/viewtopic.php?f=5&t=59477 Tip. It's a lot easier to do accurately before the fork is removed from the frame than after.

Nice one. Had some useful info it that! Cheers

So, which track fork 11/8 is known to have the lowest axle-crown measurement? (it's not the PlanetX track, might be the wing pista http://www.dolan-bikes.com/media/wysiwyg/dolan/df4-frame-geometry.jpg).

What effect does rake have on tyre to downtube clearance and how can it be calculated? I have forks with 52mm rake, 28c tyres on 700c wheels with a 20mm gap between tyre and downtube. If I lower the rake, is it possible to calculate the new clearance (distance between tyre and downtube)?

Ignore that. Figured it out using secondary school geometry. Maths wins.

73 deg head tube
45mm take
376mm a-c
28mm tyres

Nothing very radical there, so why does this bike have so much wheel flop, and little desire to stay centred without hands on the bars?

why does this bike have so much wheel flop, and little desire to stay centred without hands on the bars?

...did you turn your fork the wrong way around/happy hour on the pub/riding tandem on rear seat?

Everything is kosher as you said

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By flop I meant that, for example, when pushing the bike holding the saddle there is a tendency for the wheel to turn to the side... this tendency is accentuated when going slowly, and easily results in the wheel turning to its maximum extent. It doesn't make sense given the spec, unless the components are not actually as specced (unlikely as all reputable makes). Any other factors I'm overlooking?

Can you post a picture of the bike seen from the side?

Will do... I'll have to take one

Wheel flop is driven by gravity. The height of the crown race drops as the steering angle approaches 90 degrees.

Weight in front of the steering axis will aggravate the flop tendency.
Could be heavy wheel, rack, bars.

Is the fork original to the bike?

A longer fork will slacken angle and cause slower steerer thus a little harder to ride no handed.

Is the fork original to the bike?