|170mm fat bike hub|
To be sure- fat bikes weren't always "fat". Once they were ordinary mountain bikes. Riders found that the tires punched through the snow too easily, so there were a few tinkerers around that began to experiment.
These fellows first welded two rims together making the wheels wider, and mounting tires on that, then wide rims were made, and you know the rest. Frames had to be modified along the way. Of course, limitations existed.
One of those was the hub width of 135mm. Eventually, with the advent of single speed hubs, someone got the idea to use a rear single speed hub as a front hub, thus widening the front out to match the back, and allow for wheel swaps in case of free hub failure. One could put the front wheel in the back, and run the bike as a single speed, or fixed gear bike, to bail themselves out of the Arctic wilderness.
The Surly Pugsley picked up on this Arctic/Alaskan idea and propagated it with distribution to all corners of the earth for several years. Being able to use standard parts was important not only for survival in remote areas of the Northern latitudes, but for folks piecing together one of these from Surly's frame, fork, tire, and wheel parts that were fat bike specific. It made sense then to use the "off set" frame idea.
|Pugsley- The Standard Bearer|
While there isn't really anything wrong in practice with an off set frame and off set wheel build to fit it, the symmetrical wheel build and frame theoretically should be a stronger wheel. Plus, it just looks less goofy. But again- Pugs and Moonlanders, (another Surly offering with an even more radically offset frame), are working great for a lot of riders.
However; it seems to this writer, just looking around the fat bike landscape, that Surly and maybe one other company are the only 135mm offset flag bearers, while just about everything else is a symmetrical rear/170mm layout. Which begs the question: "Is the industry going to 170mm rear ends and if so, where does that leave Surly and their fans?" Not that Surly or their fans care, but I just find it intriguing to think about.
I think I know at least part of the story concerning why it is that Surly so doggedly holds to it's ways of doing things concerning fat bikes, but ya gotta wonder, is that going to make sense five years from now? Ten? I wonder.
It's interesting to sit back and think about that, or better yet, think about that while riding your fat bike!