Bike Geometry

Peddle Up!

I'd like to nderstand better how a bike's geometry affects the "feel" and handling of a bike. What are the major factors and why are they important?

Thanks.

morrisje

There are a couple of basic elements that are the ones important to me.

1./ Top tube length - how strethed out you are
2./ headtube length - how bent over you are

I know there are complex angles that determine how quick the bike nadles, etc. But if you are looking at with the bike fit you then top tube and head tube are the most important.

anto164

head angle - how fast/slow the steering is, this also changes the wheelbase which changes the stability and handling whilst at speed. Too steep means the steering gets twitchy, too slack and the steering slows down too much.

The main ones are the top tube length and the headtube height as stated.

Monty Dog

There are two variables here - bike fit and how well a bicycle fits the individual and then how geometry affects the handling characteristics of the bike itself - these two are linked but in a lot of respects are independent variables. It's perfectly possible to make two frames that fit an individual, but one will handle completely different to another!
Knowing what size of frame suits you is also dependents on the proporitions of the body, flexibility and relative strength - there's plent of resources available about this online.
In terms of handling characteristics, it's not just about frame and headtube angles but also about trail which is the distance between the steering axis and where the tyre actually contacts the ground. Generally, more trail provides greater stability - but trail is determined by a number of factors including headtube angle, fork length and offset.