I have to admit I’m having some misgivings about touring on the Pugs. The problem is the Q factor of that 100mm bottom bracket shell. It tweaks my knees just a bit. It doesn’t really bother me at present, commuting 8 miles at a time, but I worry about riding 30-40 miles, day after day while on tour. A small annoyance can become crippling in circumstances like that.
Another problem with touring on the Pugs is that the offset wheels are not something you are going to find at every small-town bike shop.
So I started thinking about how one could fix these problem on a fat bike. Some fat bikes use a 170mm rear hub, which allows for a symmetric wheel while still providing proper chainline. But 170mm hubs are a rarity. You could build a symmetric frame with 135mm rear spacing, and simply not use the 2 or 3 lowest cogs on the rear (or space the cassette over and lose the 2 or 3 highest cogs instead). But if you think about it, the rear tire size mandates a minimum bottom bracket width: even if you built a custom frame, the BB would still have to be wide to prevent the crankarms from striking the chainstays.
This led me to thinking about going half-fat: fat on the front, fat-lite on the rear. Surly frames in general have a reputation for taking fatter-than-average rubber. Many people report having run 3″ wide tires on a Karate Monkey for example. It got me thinking that the perfect off-pavement touring bike might be a KM or the new Ogre 29er. With a straight (non-offset) Pugsley fork on the front, you could have symmetric wheels both front and rear, with room to run a Larry up front. I’ve found that Larry on the front eliminates the need for a suspension on anything but really gnarly stuff.
Now the question is, is this enough cushion in the rear? According to my calculations, the volume of a Larry is about 13 liters of air; the volume of a 29×3 is about 10 liters. (Compare with other tire volumes on this chart.) This is not too bad. I guess the only way to answer this question with certainty is to try out a few different tires on the rear of the Pugs. Worse comes to worst, a Cane Creek Thudbuster could be used to smooth out the bumps.
This all begs the question, is this even a good idea? The biggest problem with using a setup like this for expedition touring is that the tires are not interchangeable between the wheels. Worse yet, you can’t even carry a single spare that would work on both wheels – Larry fits on a 26″ rim, and the rear wheel is a 29er! This would seem to spell doom for this approach.
But hold on a second. When I tour, I plan to use an Extrawheel Voyager trailer to tote my gear. The Extrawheel is rather unique among bike trailers in that it uses a full-sized wheel. This allows you to use it as a spare wheel in an emergency. The trailer (w/o wheel) is extremely light – about 5 pounds. The 3rd wheel is not all wasted weight, however, since it obviates the need to carry a spare tire, at least. In the extreme, if you were to completely destroy one of the bike’s wheels, you could ditch the trailer (literally) and cannibalize the trailer’s wheel to get you to the nearest town where you could have a replacement wheel shipped.
So the strategy would be to use the same 29 x 3 semi-fat on the trailer as is on the rear of the bike. Now the trailer wheel can swapped with either of the bike’s wheels (the Extrawheel is able to accomodate a 3.7″ tire). Note that the big disadvantage of using the Extrawheel with a Pugs is that Pugs wheels are damn heavy, and having to accelerate a third one is not something I’m looking forward to! But with the half-fat setup, two of the three wheels are lighter than a Pugs wheel.
To summarize, the propsed setup is:
- Karate Monkey or Ogre or similar 29er frame
- Replace fork with a Pugsley non-offset fork
- Larry on the front
- 29 x 2.5-3.0 on the rear, whatever fits
- Extrawheel trailer with the same 29er wheel