That’s short for “Old Guy’s All-Terrain-Bicycle”…or Old n Grumpy ATB, or Original Gangsta ATB.
Being almost 50 now and riding bikes for most of those years I’ve seen mountain bikes go from my first mountain bike – a 1984 Schwinn High Sierra with bull-moose bars, to what i thought was the peak of engineering with my 1996 Moots YBB. Now we have what look to be motorcycles without engines that weigh less than my custom built Ti hardtail. It’s pretty stunning the change, the progression, the diversification of pedal bikes in the last 40 years. Being a diehard fan of rigid and hardtail mountain bikes I have never owned a full suspension bike and only ridden a few. But I’ve ridden most every variation of a hardtail bike one can imagine, to draw experience from when I build new bikes.
If you don’t remember the 90’s, or weren’t alive then, pretty much every mountain bike made had the same 71/73 (hta/sta) geometry and long stems (120+). There were small builders doing different things but not until Fisher made the first G2 geometry bikes in 1998-ish did everyone else see the changes and progression. With the mass introduction of the 29″ wheel starting in 2001 with another Fisher…well it all went haywire starting the wheel size revolution that we are still seeing now.
But back to that first G2 Fisher in the late 90’s. I remember these bikes very well since a friend of mine let me ride his prototype training bike and it was obvious how much it was a departure from the norm. At the time I was riding a Moots YBB and thought it was the best thing in the world (it kinda was). But on this new Fisher i felt better climbing AND descending. The angles stayed similar but but the chainstays got shorter and the front center and top tube got longer. A few years later, Fisher got Rock Shox to make a higher offset fork (51mm) that would reduce the trail to account for slackening the head tube angle, which is what most people remember as being “G2 geometry,” but the first change was the change in frame proportions that generally affected weight distribution on the bike and made it a step closer to what we all like today.
To put this in perspective, a large frame went from about a 24″ to 25″ effective top tube length with the cockpit length difference being made up with a shorter stem. Most were riding about a 120mm stem so changing to a 90mm stem was a crazy, anything under 100mm was considered VERY short and I don’t remember many stems being available in that length. Fisher wasn’t the first to come up with this geometry idea though. Interloc Racing Design released a bike in 1989 with a 76 degree seat tube angle, shorter chainstays and longer top tube. Around the same time, Doug Bradbury made Manitou frames with longer front ends, shorter chainstays and shorter stems. There are quite a few things Bradbury did that didn’t catch on until many years later, like wider hub spacing for stronger stiffer wheels, or a frame with an asymetric rear triangle and an elevated driveside chainstay (like the Trek Stache+ and later the Salsa Woodchipper).
The thing about bikes is that you can do most any ride with almost any bike, unless you’re racing. Then dialing it in can be more important to you than the rest of us. But asking what’s the “Best gravel bike” is just not the right question, it depends on what type of riding you do and how you ride bikes in that terrain. That’s why custom is so cool! As an example, i built myself a bike that is my idea of a gravel bike, but some would call a 90’s mountain bike with drop bars, or a dirt-drop. I call it and old-guy’s all-terrain bike (OGATB). It shares aspects of an MTB like a (non-Boost) chainline and Q-factor as well as bigger tire clearance, but is built for cross/gravel bike parts, the shorter axle to crown fork, and 100mm axle spacing in front. The result is a really fun bike that can handle a lot more than you’d think it should, and a great bike-touring partner with the big frame bag space, adjustable dropouts to lengthen the wheelbase or convert to a singlespeed, and lots of mount locations with a steel or carbon fork (i.e., Rodeo Spork or ENVE Adventure). Not being right near mountains and technical trail riding this has become my go-to bike. Not great on paved road or rocky trails but good enough on both and great on everything in between.
The geometry is built around 29×2” tires but the frame and fork can fit 2.3’s. The bottom bracket drop is 84mm – much lower than a mountain bike but with the big tires on it’s as low as a gravel bike (280-290mm depending). Chainstay length is 425mm with the Paragon Rockers forward, and the angles are 69/75 deg (HTA/STA). Effective top tube length is about what you’d see on your own gravel bike but a little longer probably as it’s designed to be used with a 90m stem, at most.