I remember when I got my first roadbike (one of those modern taiwanese aluminium bikes, with crit geometry and 105 components) I was quite impressed about how when I pushed on the pedals hard there was an imediate reaction from the bike. I remember inadvertantly raising the front wheel quite a bit. It felt great.

My question is: is this 'responsiveness' a function of the frame? if so, what does a frame need to achieve this? stiff rear triangle? short chainstays? And would it be possible, for example, to make a lugged steel frame with the same responsiveness?

Of course it could be a function of other components...

I would guess you could get a similar or equally responsive frame in steel just because so many people prefer the feel of steel to Al.

When one looks ar subjective catagories like this it gets pretty difficult to catagorize them. I was studying puters at one time, and it seems obvious that the better feel of certain models would be the result of vibratory response in head in and shaft, the relation ship of center of rotation and the center of mass of various heads. Lots o nice mechanical differences. One study showed that what putters interpreted as putters with a prefered feel was substatially an auditory catagory particular puters gave sound feedback better than others, but golfer were convinced they were feeling it in their hands. When ear muffs were worn they found feedback significantly worse.

To me a tool with good feedback is one where the inputs I give I can gage by what I feel back. But what exactly the source of that feeling is, may be complex.

Actually another auditory example is people will say a gun has unpleasant recoil if the muzzle blast is brutal.

"Responsive" is one of those esoteric terms people often use to describe a bicycle. It is not quantifiable in any way. You need to better define what you are interested in doing. For example, a frame that steers fast or a frame with a lot of bottom bracket stiffness. Both of these things can be designed into the frame but "responsiveness" can not.

Typically people can not articulate their needs so the designer/builder makes the decisions. A stiff frame with short chain stays and a steep head angle is often labeled "responsive". A frame like this can be made out of any material. It typically gives up some comfort so keep this in mind if you go down this road with a custom builder.

True, which is why I did so in the first post, might've helped if you'd read it

I am talking about responsiveness in regards to pedal input, not steering.

Okay, I went back and read your first post again. You asked a question related to "responsiveness" but don't actually discribe what you want to achieve other than "...when I pushed on the pedals hard there was an imediate reaction from the bike". What kind of reaction did you experience? I assume you are talking about bottom bracket stiffness but frankly you are pretty vague in your description. You also mention something about raising the front end of the bike so maybe you are looking for something with a rear weight balance bias?

My guess is that a frame with short chain stays (for rear weight bias) and a stiff bottom bracket might be what you are looking for. Just a guess though based on your description.

Ok, when I pushed down on the pedals I noticed a very sudden jump in speed. The crank felt very 'connected' to the rear wheel, there wasn't a vague feeling there at all.

The rising frontwheel wheel I could have done without, TBH.

So is that a function of bottom bracket stiffness? if the bike had longer chainstays (they were 41cm) would it have felt less responsive to my pedal input?

You're right, it is a very hard quantity to explain.

Really this discussion is going on about two different things: a perception by the rider about how a bike responds, and a discussion about what is done in the design that might achieve that result. Getting those different types of imformation confused can lead to well, confusion.

Road Fan

I think the OP is asking for help connecting the two. The immediacy of the acceleration he feels is likely a function of a stiff bottom bracket, and stiff (read short) chainstays. I'm not expert in these things, so maybe someone who knows more could help out. What frame characteristics lead to a "responsive" feel?

I've ridden super stiff through the bottom bracket frames before and don't think that they are particularly beneficial. The older Klein frames for example will skip the rear wheel if your sprinting spin is too choppy. A little sideways flex at the bottom bracket tends to smooth out the power delivery to keep this type of behavior at bay.

I know exactly what the OP is talking about. And I too have wondered what makes one bike responsive while another, nearly identical bike, is not. I don't understand what a stiff bottom bracket means but I will go back and check the length of the chainstays.

Not sure if there still is an issue for this was 8 years ago. But thanks for the suggestion.