What makes bikes handle?

[Brucey]

Re suspension; suspension forks can do all kinds of things which you may find unsettling in corners, e.g.;

-worn bushings, inadequate lateral stiffness etc can lead to unwanted and unnecessary movements of the fork which degrade the steering feel.

- the action of the suspension itself will change the castor angle and the trail as the suspension loads up and compresses, mid corner, as well as over bumps, or on the brakes.

- the suspension action can mask or change the feel of the tyres

Motorcyclists get used to this kind of thing, but then they have different profile tyres, different suspension action and different steering geometry etc to start with. Even so it can be difficult to ride a machine in smooth curve; with certain bumps or weight changes the bike wants to go on a 'thruppenny bit' line which is rarely the fastest one.

Bicycle suspension forks are generally 'disappointingly crude' in their action. Without a good deal of fine tuning (or more likely complete re-engineering...) they are unlikely to actually make the handling better in corners in any way.

cheers

[Claireysmurf]

I've taken to locking my hardtail fork out for almost everything now and may yet buy a rigid fork. The gut wrenching part was probably not being used to the bike and turning in a little too quickly and feeling the fork compressing and the bike run wide.

[531colin]

.............. I assume the geometry is fairly similar................

I don't think that's a safe assumption. I have found a few scraps of information, I don't know if either bike geometry changes with the year....many do, who knows why?.....
The C de F head angle varies with size from 70.75 to 72 deg.....fork offset is not quoted.
The clubman (in the size tested) was 72.5 deg. head, 45mm offset.
I infer that the Clubman is likely to have livelier steering than the C de F......possibly in any size......(unless the C de F fork is long offset...ie more than about 55mm)

Clubman geometry...http://www.ctc.org.uk/file/public/bike-test-audax-bikes.pdf
C de F......http://www.genesisbikes.co.uk/bikes/frames/adventure/croix-de-fer

[Claireysmurf]

These are mere numbers to me I'm afraid. From riding both bikes I made the assumption about geometry from the point of view that the Clubman was regarded as fairly relaxed by the standards of a full on road bike and that the Croix de Fer is fairly aggressive for a cross bike/potential tourer. In saying this I am probably making my main judgement on relative height of handle bars to saddle.

Interestingly my Croix de Fer's handlebars were only slightly higher than the stock height of the Raleigh SP's. My bike has an adjustable stem and an uncut steerer tube (with the stem spaced as high as it will go) and so is possibly a fair bit higher than a standard model. The Raleigh seems to come as standard with 45mm of spacers.

[blackbike]

The biggest influences on bike handling for me, assuming you have a reasonable quality bike, are being young, thin and fit.

I can still do thin and fit.

[LollyKat]

These are mere numbers to me I'm afraid. From riding both bikes I made the assumption about geometry from the point of view that the Clubman was regarded as fairly relaxed by the standards of a full on road bike and that the Croix de Fer is fairly aggressive for a cross bike/potential tourer. In saying this I am probably making my main judgement on relative height of handle bars to saddle.

The numbers are important, though. I think (Colin will correct me if I am wrong) that seemingly tiny differences in head angle and fork offset make a much bigger difference to handling than the height and reach of your handlebars.

Bike design is very subtle and I barely understand it....by the time you factor in all the other variables such as frame tube materials and dimensions, chainstay length and front centre, tyre size and type...... I'm happy to leave it to the experts.

[531colin]

.............. I assume the geometry is fairly similar................

I don't think that's a safe assumption. I have found a few scraps of information, I don't know if either bike geometry changes with the year....many do, who knows why?.....
The C de F head angle varies with size from 70.75 to 72 deg.....fork offset is not quoted.
The clubman (in the size tested) was 72.5 deg. head, 45mm offset.
I infer that the Clubman is likely to have livelier steering than the C de F......possibly in any size......(unless the C de F fork is long offset...ie more than about 55mm)

Clubman geometry...http://www.ctc.org.uk/file/public/bike-test-audax-bikes.pdf
C de F......http://www.genesisbikes.co.uk/bikes/frames/adventure/croix-de-fer

Raleigh comp SP 2012 geometry here......http://www.mailorderbikes.com/info/raleigh_road_bike_sizing_guide_2012.php

offset varies from 43 to 46mm (Bit subtle for me!) head angle 72 to 73 deg.....not significantly different from the Clubman as above
The C de F has the more stable set-up of the 3 bikes, as I would expect.

[reohn2]

The biggest influences on bike handling for me, assuming you have a reasonable quality bike, are being young, thin and fit.

I can still do thin and fit.

You mistaking handling with how fast someone can make it go .

[reohn2]

Colin's asked this and I agreed with him.
What does the OP wish to achieve?
I would seem that whatever it is the Croix de Fer hasn't realised it,that's not be a fault of the bike but of the expectations of it IMO.

I have almost created 'every bike you ever need' but something that feels far less lively than I had hoped

.
The Croix de Fer I'd imagine weighs about 13kg and is being ridden on 28mm(stodgy by some standards)Marathon tyres,you simply cannot have the liveliness of an all out road bike with that set up.
A 'bike for all things' has to have compromises,the trick is minimising those compromises,I'd suggest that the right tyres will 'liven up' the bike,but it'll never be an out and out road bike.
The right tyres(at the right TP's) will also make it more comfortable too.
I'd also suggest,going off reviews,the handling is pretty neutral and steady at slow and high speed.

[Claireysmurf]

Colin's asked this and I agreed with him.
What does the OP wish to achieve?
I would seem that whatever it is the Croix de Fer hasn't realised it,that's not be a fault of the bike but of the expectations of it IMO.

I have almost created 'every bike you ever need' but something that feels far less lively than I had hoped

.
The Croix de Fer I'd imagine weighs about 13kg and is being ridden on 28mm(stodgy by some standards)Marathon tyres,you simply cannot have the liveliness of an all out road bike with that set up.
A 'bike for all things' has to have compromises,the trick is minimising those compromises,I'd suggest that the right tyres will 'liven up' the bike,but it'll never be an out and out road bike.
The right tyres(at the right TP's) will also make it more comfortable too.
I'd also suggest,going off reviews,the handling is pretty neutral and steady at slow and high speed.

What do I want to achieve? A better understanding of what factors affect a bike's handling. I don't have a Croix de Fer. I have a Croix de Fer frame plus some other bits so if need be I can always swap the frame or the wheels as I can the cassette etc. I have what I set out to have which is a bike for most occasions.

[531colin]

Factors affecting a bike's handling are pretty much as Brucey listed in the first reply on the thread.
The real difficulty is defining terms like "lively" or "sprightly".
How a bike feels in a turn is largely governed by steering geometry and front tyre drag.
How fast it "feels" is probably governed by how fast it is, how much it bumps and frets on poor surfaces, how it feels in a turn, and how it feels to pedal.
how fast it is is governed by revolving weight, frame stiffness, tyre drag, aerodynamic drag,
how much it bumps and frets is governed by tyre size, fork stiffness and steering geometry
how it feels to pedal is frame/fork/wheel stiffness

theres an awful lot to go at, and some of it is very difficult to isolate, let alone quantify.

[james-o]

The first impressions of the handling of the Raleigh suggested that it didn't grip that well on a smooth, damp tarmac car park and I assume that was due to the 23mm tyres. However, doing the same thing (lots of tight-ish turns at moderate speed) on my Croix de Fer made me think how much more slowly and sloppily (not sure that is the right word) it turned in.

73 (I'd expect) head angle and 43-45mm rake fork and 23c tyre, vs a 71.5 head angle on the CdF with 45mm rake, plus a bigger tyre I'd guess. That's going from traditional road race geometry to a relatively laid-back cyclocross geometry, from one end of a scale to another almost. The difference in trail (that gives the steady vs light, sloppy/stable vs tight/nervous steering) is quite a bit I'd say. The Raleigh should feel great on smooth dry tarmac and potentially skittish on anything rougher, wet etc. The CdF would be good on dirt tracks and muddy paths but slow / lazy (verging on excessively so some would say) on good tarmac (unless you're at 45mph on a downhill maybe).
Try the 23c on the Genesis as an experiment if you haven't already, it'll make a fair bit of difference, or go for a more Audax geometry bike as a compromise between the two - 72 head angle on the same forks. Ideal for UK roads imo. eg Spa Audax, Genesis Equilibrium, Paul Hewitt has some nice examples, there's a few out there and so many riders I see on race bikes with 'race blades' in winter could be better off on them ('image' aside).