Monday, June 11, 2018

Bicycles for the unpaved - the "third way"?

Warning: This post contains a large amount of technical information, which means it can be digested only by real bike tech nerds.

I remember my teenage years in mid 90's when world of bicycles was very black and white. On one side we had mountain bikes with their slacker (at that time) head tube angles of 67-71 deg and on the other - road bikes with head tube angles of 73-74 deg and a classic "square" road bike geometry.

But with the arrival of gravel and adventure bikes and many more wheel and tire options, this bipolar world got a lot more complicated. Now it seems that should we be interested in riding on unpaved roads, the bicycle industry offers mainly two types of drop bar bicycles.

One is a gravel bike that is essentially a modification of a road or cyclocross bicycle with 71-72 deg head tube angle and more clearance for fatter tires. These very sporty bikes are typically chosen by folks interested in racing in events such as Trans Iowa or Dirty Kanza.

The other type comes from the old 50's French school of cycling and is embraced more by the adventurous people who are interested in randonneuring and touring. They firmly believe that a steep head tube angle of 73 deg combined with lots of fork rake, which results in low-trail geometry is superior to anything else.

But all this made me wonder - is there a third way? Can a bicycle be designed differently than either an agile gravel rig or a low-trail two-wheeler and still remain comfortable and stable over rough terrain?
This third way approach has been embraced by many small American custom frame builders. One of them, 44 Bikes, ran by Kris Henry, is located nearby in New Hampshire. Since my new bike came directly from his shop, I will use it as an example to describe what this third design option is.

If modern gravel bikes are still racing road bikes and modern low-trail bikes are in fact retro road bikes, my 44 Huntsman is somewhat a "mountain road bike". It borrows heavily from MTB world when it's required. This bike has a very slack head tube angle (By road bike standards!) of 70 deg, which combined with 45mm fork rake results in a high trail geometry and puts it almost in MTB category. Similarly, stem remains short at 80mm to keep steering more responsive. To compensate, top tube is slightly lengthened, in order to maintain proper distance between handlebars and saddle.

The rear triangle is perhaps more traditional, but still MTB-like with lower seat tube for increased standover and short-ish chainstays of 435mm. These allow for quicker turning without the long, "waggy" tail feeling but still provide ample clearance for 2.25" tires.

So is it maybe a mountain bike dressed up as a road bike? Well, not exactly. It's a pretty clever mix of both. Borrowing from it's road bike heritage, Huntsman has a larger bottom bracket drop of 70mm, meaning more stability and lower center of gravity. Also, bottom bracket shell is 68mm wide - another road standard.

This thing rolls on 650B (or 27.5") wheels and 2.20" tires. It's a good compromise between wheel diameter, weight and required space in frame and fork for fatter tires. As an added benefit, the wheel diameter is exactly the same as 700C wheels with 35-38mm tires, which means that theoretically I could swap my current wheels with more road-like ones in a few seconds, should I plan to ride on pavement only.

In terms of comfort and handling I have no complains. Thanks to lots of trail and wide tires it feels very stable over rough terrain. Because it handles a bit like a mountain bike, my Huntsman needs more steering input to guide front wheel. That's a good thing. The last thing you want on rough downhill at high speed is a floppy front wheel. This is also where the 46cm wide Salsa Cowchipper bars come handy.
As you can probably tell by now, the whole thing was designed more for comfort than speed. This is why the head tube is tall enough to place handlebars higher than on a regular road or cyclocross bike. With frame stack of 605mm I can keep my back a bit more upright and don't have to look at the front wheel all the time. And thanks to the slack head tube angle I can avoid annoying toe overlap even with very wide tires (and fenders) - something that many cyclocross and gravel bikes may struggle with.

There are also some minor details I'd like to mention, since many of them are non-standard in mass-produced bikes. The frame has provisions for 3 bottle cages but I requested the one on seat tube to be placed as low as possible. This is to make as much space under the top tube as possible, should I use a half frame bag at some point in the future.

There are full fender mounts on frame and fork but the one on seat stays has the screw hole aligned towards the wheel axle. Similarly, there is a hidden threaded hole under the fork crown. All this means that fenders can be bolted directly to the frame and fork without using any L-shaped brackets.

The fork comes with "everything but the kitchen sink" as Kris called it once. There are fender mounts, rack mounts, internal and external dynamo wiring guides.
I won't get into details about my component choices here, but one thing worth mentioning is the drivetrain. I debated whether I should build it as 1x11 speed, but ultimately decided to go 2x11 simply because it was cheaper (I could reuse a lot of parts from my old bike). As such, I'm running a wild mix of components: Shimano 105 (5800-series) shifters and rear derailleur, SRAM 11-32T cassette, Sugino OX601D crankset with 42/26T chainrings and Shimano Metrea front derailleur. You may scratch your head asking - "why?", but it's actually quite simple:
  • I wanted to use Shimano STI shifters, not SRAM.
  • I wanted to use 2x11 system with low gears that would work well with those shifters.
  • Sugino crankset lets me run chainring combo I find most useful: 44/28T, 42/26T or anything similar.
  • Metrea is the only front derailleur that works with 11-speed Shimano shifters and is designed for smaller size chainrings (that is, much smaller than 50T - the road "Compact").
It was fun putting it all together, although, certainly the most challenging part was... avoiding black color. Maybe that sounded a bit weird, but I simply had this particular color scheme on mind - rusted-looking frame and fork with most components in polished silver. The problem is - many modern components come only in black or dark grey. Those classic, high-polished parts are now quite rare and while I could find brakes, seatpost or stem in this finish, handlebars, cranks or derailleurs were pretty difficult to get. This is the reason why I had the handlebars powder-coated to match frame (Cowchipper bars are only available in black) and I ended up customizing many components by hand-polishing them: crank arms, brake adapters, derailleur cage and light mount - all of which weren't available in the finish I wanted.
Finally, to be completely honest, this bike is not without flaws. Well, maybe not flaws, but some minor drawbacks. First of all, it's noisy on pavement, which is clearly due to MTB tread pattern on Maxxis tires. And speaking about tires, I noticed that they pick up all dirt from road with ease and my bike ends up being sprayed with mud every time I ride (fenders, anyone?).

It's also not exactly lightweight. It carries lots of extras that many "regular" bikes lack - rack, basket, dynamo hub, lights, etc. With all that added junk my Huntsman reaches 12.7kg (28lbs) but if you want to compare it with other, similar bikes you would need to remove all these parts. Then you get a more manageable 11.6kg (25.5lbs), which is about the same as Salsa Fargo or Journeyman. These "issues" don't bother me much since it was never my intention to make this bike a fast, racing machine.

Unfortunately, if you want a bicycle designed and built this way, you would need to go custom and rely on small frame builders (Such as 44 Bikes from NH, Matter Cycles from CO or Sklar Bikes from MT). So far, none of the large bike manufacturers has embraced this design concept. Maybe they will. Soon?

3 comments:

  1. New Bike Day?!

    Very nice! That's an interesting finish. Is it matte, textured, or smooth?

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    1. It's matte and just slightly textured. If it was more textured/rough, it would be probably hard to clean.

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    2. Very cool, man.

      To many happy miles!

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