Saturday, April 18, 2015

Modern Drop Bar Bicycle Geometry, Explained!

The bike industry has been changing road bikes over the last decade to better suit the different styles of riding that exist.  We have been hearing all sorts of new terms for them but we haven't really had those all explained in one easy place.  That's what this write-up is about. 
This is what started them all... Its a fast bike with minimal tire clearance, lower handlebar position, caliper style brakes and is the lightest of the bunch.  Most of them will come with 23mm tires but can fit 25mm tires.  They are great for road-only, longer rides, intense paced riding, group rides.  The customers that are looking at these are looking for the lightest and fastest bikes out there.
These are closely bread from road bikes, the first ones where road bike with different brake mounts installed for canti brakes with mud clearance in a time when road bikes where steel and had more tire room (the 60s-70s).  They changed into their own style of bike in the 90s because road bikes no longer had clearance for the tires and the style of racing grew.  Now the differences are ability to fit at least a 32mm tire, disk or canti brakes, higher bb height (for tight off-road cornering).  Many have fender and rack mounts to make them more versatile but they do generally have a pretty aggressive road fit and pretty quick handling, often the same as a road bike.
These bikes have been around for a long long time.  They resemble a cyclocross bike however they have many geometry differences.  Mainly they are designed for going in a straight line for a long distance so their chainstays are much longer (also gives more heal clearance for panniers), the headtubes are usually a slacker angle, a lower bb height and the handle bar height is higher, often as high as the saddle. They have all the rack and fender mounts (front and rear) and have a bit stiffer frame for the added weight of touring.
This is a bike that has also been around for a while (some call it a light-touring).  The simplest way to describe them is a touring bike with lighter tubing for a better ride quality. The fashion for these have been to add shiny fenders and a front rack/bag.  Its name comes from a style of racing/riding that is a long distance over one or two days that is fully self supported
This is a bike that branches out from a road bike.  It's designed to have a higher handlebar height, more tire clearance (28mm-32mm) and a little bit more predictable handling (slacker angles). Most of the road bikes we sell are this style.  They have gone a few steps further with some brands and include disk brakes and even more tire clearance (32mm-38mm).  These are very well balanced bike and work very well for many people, they are getting a little ambiguous in that some are coming with rack/fender mounts for even more utility and can resemble cyclocross bikes. 
These where born from the gravel races that all the kids are doing these days.  They look very similar to a cyclocross bike however they have a few small but important differences.  The main ones being longer chainstays and a shorter bb height (back to road bike height with light touring chainstay lengths).  These are important in that they make the bike much more stable for high speed gravel descents.  They also have more tire clearance which can be crucial for gravel, lessening the deflection caused by the rocks that make up gravel roads.
This is the most ambiguous term we have for the bike market right now.  It can mean any of the above plus many different mtn bikes and even a few fatbikes.  It was brought into the market by Salsa cycles to describe their style or riding but has expanded to other companies or simply a way of describing how a bike is used. The key features are having more durable wheels, more predictable handling, and lots of room for stuff on the bike, but not necessarily using racks.  Because they are used off road/gravel quite a bit people prefer to have frame bags, handlebar bags and large seatbags.  These bags tend to be lighter and easier to handle in off-road situations, they also bounce around a lot less.

c/o David Meyer | Sales, Service, Fit Tech, Worker-Owner
The Hub Bike Co-op
david at thehubbikecoop dot biz