Wednesday, January 14, 2015

Pivot LES Fat: One Bike To Rule Them All?

The new Pivot Cycles "LES Fat" hard tail Image courtesy of Pivot
Last year I rode a bicycle that really opened up my eyes. It was a Borealis Echo set up not as a fat bike, but as a 29+ bike and it had a Rock Shox Bluto fork with that same company's excellent dropper post.

Their weren't too many bikes I wanted to keep as a test rider for Twenty Nine Inches, but the Echo, so equipped, was one. I had it up at the Volga Recreation Area, a place where there are big hills, challenging climbs, lots of sand, and chunky rocks here and there. In short, it has every tough feature a Mid-Western trail might have.

The Echo slayed the place, and with the 1X11 drive train and 3 inch wide rubber, it was a hoot to ride. It made me want to ride there all day, and then go find harder places to ride, because it was so capable, like a fat bike, but it was light and nimble, like a carbon hard tail. So... Well, here we have the next evolution of such an idea. Perhaps a "one bike solution" for many people.

The Pivot Cycles LES Fat is a fat bike, of course, but there are several details, and one big important one, that set this apart from many in the crowd. First of all, Pivot designed this to be different from most fat bikes because they wanted it to work with 26" X 4", 26" X 5", 27.5" X 3+", and 29+ wheel sizes. To do this, Pivot realized that 26 X 4 and "Mid-Fat" wheels have about the same wheel diameter, but 26" X 5" and 29+, which are very similar in wheel diameter to each other, are bigger wheels than the first two mentioned. Yes- by a significant amount. Regular fat bike sized wheels and "Mid-Fat" based on 27.5" has a slightly smaller than 29" diameter, while the other two measure out at slightly more than 31" in diameter. Big difference, and this causes handling and ergonomic issues.

Image courtesy of Pivot. (Red arrows are my addition!)
To allow for a swap of wheels and to keep the geometry mostly the same in all configurations, Pivot designed a special "lower cup" which can be removed to accommodate longer axle to crown measurements and not "jack up" your geometry. (Pun intended- See the image at the right for a visual)

This means that when you use a Bluto fork, and account for sag, you have removed the lower cup and you can retain the same front end angles, bottom  bracket height, and seat tube angle as you had while running rigid. 29+, 5" width tires, and Bluto forks would all be used without the lower cup. Mid-fat and "normal" sized 3.8"-4.0" fat bike rubber in rigid mode would stay with the lower cup in the head tube. Bottom bracket height can be further controlled by the swinger drop outs which go back and up to accommodate a taller back wheel.

 Those same swinging rear drop outs will allow for single speed set ups, or for tweaking the wheel base. Pivot's ported internal routing is cool, and a "stealth route" for a dropper post is also designed into this frame. Finally, an axle standard I thought might prove to become the new "standard" is seen here- 197mm X 12mm through axle rear and 150mm X 15mm through axle front is on this bike. The front wheel will swap straight into a Bluto fork. Nice.

An intriguing detail on the new LES Fat is the e-13 co-designed with Pivot fat bike crank which is said to work with 5" wide tires but still have a "tread width" or "Q Factor" which is  closer to a rear 170mmOLD hub. Pivot says it works for better ergonomic feeling especially in regard to knees and hips. However; they also claim a good chain line with a 5" tire and an ability to run a double front chain ring set up. That I'd have to see.

So, could something like this be your Winter, Spring, Summer, and Fall rig? Could the addition of a Bluto fork extend the range of this bike such that you'd never want a full suspension device? Could it be a fat bike, a "Mid-fat" bike, and a 29+ rig so you'd never want another weirdo hard tail? Maybe. The wider bottom bracket is still going to freak out many folks. (Physically and mentally) So there is that big hurdle. Oh yeah.........and the Pivot LESS Fat is expensive! There is that too. But if you can swing the dough, there isn't a bike out there with cooler details that is this versatile. I bet I'd get on with it just fine.


Unknown said...

I wonder: would a 29 x 2.1ish wheelset work just fine if pushed forward in the dropouts as if in 650B+ position?
Also, if made with the correctly spaced hubs, would this bike accomodate a road wheelset as well since BB height is less of an issue in non-trail applications?
I've been looking for a bike that would satisfy all my curiosities.
Road, 29+, 29, and possibly fat (I doubt I'd ever need or want more than 26 x 3.8 wide).

Guitar Ted said...

@ Andrew Spurlin: I don't think so. The ratio of height from a 25mm road wheel to what a 29"er or 3" fat bike tire would have is too great to really make that work. A 29"er wheel probably would be closer to reality, as far as a practical wheel for this bike. For the road, maybe consider a Big Apple 2.35 tire, which would probably fit fine and roll very fast.