-His choice of four main factors which effect handling was laughable.
wheelbase should be towards the bottom for a road bike.
rake has little effect outside of trail and weight distribution yet is listed by itself.
Weight distribution is incredibly important in handling but isn't mentioned.

-His dissection of headtube angle shows a complete lack of understanding of how a bike steers. We don't turn the bars to lean we lean to turn the bars.

-His discussion of trail while not wrong is overcomplicated by his continual reference to the position of the axle and a plumbline rather then the simpler point where the tire meets the pavement. He uses the generic shopping cart analogy but doesn't explain what it means. I'm not completely sure if he even knows. While this is not in itself incorrect it shows how he doesn't really understand the concept very well and risks confusing others.

-His discussion of speed on and off the track is laughably uninformed. The fastest bikes on the track(other then stayers bikes) have the steepest angles.

This is part of a general trend with ken cox's posting. He knows a little about bikes and thinks about things a lot. He then makes these incredibly long winded posts that are accepted as insightful due to their length and the complexity of his reasoning.

As far as his assertion that I always blast him without explaining why I usually take the time to point out all of his mistakes and assumptions since his posts are usually about fit and health and the errors are dangerous. Last night I noticed that the blowhard was up to his usual games and it was being accepted as fact but didn't feel the need to point out all of his specific errors because they weren't endangering anyone as normal.

Random thought: Has anyone ever made something like the equivalent of the Serotta Fit Bike (adjustable top tube, angles, stem length, etc) but actually rideable? That would be an awesome way to experiment with geometry on the go as opposed to on a stationary platform with no wheels or anything.

I'm thinking instead of welding the tubing together into a fixed geometry, you could just thread the ends of each tube and have it screw together into threaded lugs. You would have a set of threaded lugs with slight angle variations which would allow you to play with seat and head tube angles. Then you just screw the whole frame together and tighten it down with washers (like on a threaded headset). This would let you fine tune tube lengths and angles, and the construction might be rigid enough to be rideable (gently) so you could try the geometry out. Seems like the perfect tool for custom frame designers.

I want a bike made of right angles.

You're right, but it's still true that the headtube angle introduces nonlinearity to the steering response. It also allows you to lean while steering, something that is hard to do with a vertical HT. Just using the word "nonlinear" helped make things clear.

Perhaps, but it's not wrong, and I had no trouble understanding it.

Agreed, it was a little confusing to introduce this analogy. The explanation would be fine without it.

I think he is referring to steering stability at speed but I'm confused as well. Clearly even he was a little confused by his own reasoning. Care to 'splain it?

=====

Dutret inferred a priority which I did not imply.

=====

Actually, I devoted over seven paragraphs to the subject of rake and head tube angle, how these combine to create trail, and how trail effects handling.

Beginning:

Ending:

I then gave documented examples of known and published head tube angles and amounts of rake for two track-type bikes, one sold for the street and the other for the track.

A person genuinely interested in the conversation could, if he wanted to, have given documented examples of other bikes with different head tube angles and amounts of rake, and shared his subjective experience with these bikes.

=====

I used the generic shopping cart analogy because everyone here has experienced the castering of a shopping cart's front wheels.
For some reason, because I used the shopping cart as a method of simplifying an explanation, and because I didn't spend several paragraphs explaining intuitively-understandable castering shopping cart wheels to bicycle enthusiasts, dutret thinks I don't understand the concept.

Hm.

I wonder why dutret, then, doesn't explain it to us in terms simple enough for even me to understand.
Perhaps he will.
I would love reading about castering shopping cart wheels.

It remains, though, that I didn't spend seven more paragraphs explaining castering shopping cart wheels because I didn't think anyone had that great an interest in castering shopping cart wheels; and, besides, the mention of them had already served its purpose because everyone intuitively, if not verbally, understands why shopping cart wheels caster (they trail behind the head tube line by quite a lot, eh?).
I wonder if trail has anything to do with it.

=====

I respond to dutret because I assume people expect me to do so.

If I had true compassion for dutret, I would ignore him, wouldn't I?

My apologies to dutret for noticing him.

In the meantime, perhaps dutret would give us the real skinny on bicycle handling, and how weight distribution, wheelbase, head tube angle, rake and trail all interact.
And I don't mean "this good," and "that bad."
I mean a real explanation so we can all understand it as well as dutret does.

no nonlinearity is part of the problem. It sounds good but it does not describe reality.
Lineraity of response is the type of meaningless verbosity that kencox excels at.

1. The non-linearity he speaks of is meaningless.
2. Even it was he's talking about the bikes response to turning the handle bars. That's just not how bike handling works unless your riding under 10mph.
3. A steeper HT if you somehow managed to hold all else equal would result in a LESS responsive bike not a more responsive one since the bike would respond less to shifts in the riders weight and leaning.

It's not wrong but it completely misses the point. The only time he even comes close to explaining trail is with his passing mention of the shopping cart analogy. It makes me highly suspect that he understands trail himself.

He's trying to use the little bit of knowledge he has about bikes and his own reason to make broad unsupported generalizations. It's classic KC babble.

If anything the pista is a better high speed competition track bike then the mercian for many reasons. In general track bikes meant to be used at higher speeds have steeper hts because they also have to respond faster. The exception of course being stayers bikes which just go straight.

Road bikes on the other hand are not relaxed for high speed descent which is a tiny fraction of what they do. They are relaxed because they are ridden farther at lower speeds and don't have to respond as quickly as frequently.

dutret, you said in point 3 that a steeper headtube, if it were possible to hold all else equal, would result in a less responsive bike.
then you said the steep angle track bikes are steep because they have to respond faster.
do they respond faster because all else is not held equal...so a combination of the steep HT and the shorter rake fork, plus shorter wheelbase distributing the riders weight differently make both of those statements true?

Yes it is impossible to hold all else equal. If you increase HT angle you bring the wheel in closer. To keep trail the same you decrease rake now it's in even closer still. Lengthen the TT and you change the relation of your hands to the wheel.

In practice though within the small range between 71 and 75 degrees where most bikes are I don't think the actual effect of HT angle on steering is that great. The effect of HT angle on trail and rider position ends up being much more important.

Come on, dutret.

Instead of telling us how we have it wrong, explain it to us.

Give us your version.

By the way, a second-grader understands counter-steering.

We don't go left by leaning left, because you can't lean left (for every action...) without the bike leaning right.

And so, to go left, we steer right.

Did I really need to explain that?

In any event, I await dutret's discussion of track frame geometry.

How does the head tube angle effect rake?

I thought head tube angle and rake together determine trail.

I look forward to dutret explaining it for me.

good job you found a typo. A+ posting.

Explaining the myriad effects and interactions of every aspect of geometry is both beyond the scope of my knowledge and a reasonable message board post. Unlike you I try not to make long winded posts based on supposition and faulty reasoning. That does not mean I lack the knowledge to point out when someone like you is full of **** or even answer specific questions.

I see.

That explains everything.

My apologies.