Wednesday, May 06, 2015

Fat Fargo: Thoughts On B+ Wheels

A Gen II Fargo with fatter wheels
As stated yesterday, I wanted to lay down some thoughts on the B+, 27.5+, 650B+ or whatever these are going to be called.....wheels. Let's say "mid-fat" and leave it at that, shall we?

For those of you that are not familiar, and to give those folks interested in specifications their dosage, here are the pertinent features of the mid-fat platforms and also my specs on this wheel set.
  • Mid-fat or "plus" sized wheels are really just larger than average tires with high volume on rims you already know and love. There are a few wider rims out now as well. 
  • Mid-fat tires can be fitted to the 650B/27.5 or 29"er based platforms. Rim specs in terms of diameter are the same- 622ISO for 29+ and 584ISO for B+/27.5+. Typically, the wider rims are better, so anything with a 30mm wide width or wider works best. Some are 50mm wide, like Surly's Rabbit Hole and Sun Ringle's Mulefut.
  • Tires are typically going to be either side of 3 inches wide with a lot of height/volume to the casings. 2.8" to 3.25" seems to be the working range so far. This is for both diameters out there that are being pushed- 27.5+/B+ and 29+.
  • Wide rims and fatter, higher volume tires make for big overall diameters. For instance, a 50mm wide rim with a 3.25" "B+" tire is the same diameter, more or less, as a 29" X 2.25" tire. A 29+ tire at 3 inches wide on a 50mm wide rim is approximately the same overall diameter as a 4.8" wide fat bike tire on a 100mm wide rim- 31 inches or so. 

Now for my Fargo wheels, I used 35mm wide Velocity Blunt 35 rims and put some 2.8" WTB Trailblazer tires on them tubeless. This brings the diameter of these wheels to just slightly less than a 29 X 2.2" wheel. That means my bottom bracket is ever so slightly lower. Otherwise, there was plenty of room in the frame to fit this wheel in my Fargo. Now.....why would you do this? That's the big question, and what I wanted to seek out was an answer that satisfied my curiosity. This may not be your answer, but I feel it makes a lot of sense.

The whole "plus" size/mid-fat thing is an attempt to take advantage of fat bike volume, flotation, and grip in a package that isn't so cumbersome, heavy, and that doesn't require weird frames with wide bottom brackets which hurt some folk's knees and whatnot. Are they "fat bikes"? That's a question folks debate. I own both fat bikes and this B+/mid-fat bike. My Fat Fargo is not a fat bike. Nope. Not even close.

But, it isn't like any of my 29"ers either. I have a 29 X 2.4" tired rig that runs 45mm wide Velocity Duallys. While the footprint of those wheels are as big as my mid-fat/B+ tires, they don't have the volume of those B+ tires, and there's where your differences are and why it may make sense to run a mid-fat/B+ rig for you.

The Singular Buzzard with 29 X 2.4" tires on Velocity Duallys
That volume allows for lower pressures without fear of rim strikes. Lower pressures mean the tires conform to terrain features better, which equals more grip and control. The differences are minute, to be sure, but palpable, and in the right rig, a B+/mid-fat set up may make a lot of sense. I thought it worked great on a single speed, for instance, where grip and the lack of suspension might be your set up. I also wanted to try this as a set up for a bikepacking rig or bagged hauler/tourer/versatile mtb set up. That's where the "Fat Fargo" comes in.

My thoughts were that my original Fargo Gen I was the perfect candidate for these wheels, since it wasn't suspension corrected, and a little comfort would be welcomed there. However; the tire clearances in the chain stays were too tight to allow for mud clearances, and I felt the bottom bracket on that bike with the B+ wheels was too low. Bummer that, but I wasn't going to quit just there.

I had the Gen II Fargo, so why not slap those meats into that frame and see what's up. Well, the clearances were really good, and the bottom bracket, while slightly lower for sure, isn't too low, for me. Maybe for you it would be, but so far, I've been just fine with things this way. Of course, the Gen II has a Rock Shox Reba on it and that combo is pluuuuuusssssh. The fork has 80mm of travel, but with the tires, it almost feels like my 140mm of travel on my Buzzard.

I wish this would've worked better.
I do have the rigid fork for the Gen II bike, and that will be the next thing I try, but for now, I have a brief list of "Good" and "Bad" things that I have found running these mid-fat wheels on my Fargo. This certainly isn't a list that is comprehensive or finished yet, but here you go....

Good: The ride is super smooth. The smaller bumps disappear, bigger jolts are mere annoyances, and curbs are swallowed with little to no lifting of the front end. Grip is amazing when the conditions are ripe. Stability at slow speed is enhanced. The smaller sized wheels are easier to spin up by a long shot over 29+, but they do not give you near the momentum carrying capacity of either 29+ or a straight up 29"er wheel. There is more float, and so these carry you into looser terrain a bit further than does the "normal" 29"er wheel and tire.

Bad: Weight. First and foremost, you have a heavier tire and wheel overall than you would a good quality trail wheel in a 29"er format fitted with a good 29"er tire. That means that a 29"er wheel is easier to get going and keep going than these mid-fat wheels, which is most apparent when speeds are higher on harder packed terrain. Rolling resistance- The way the tread hits the trail with these mid-fat wheels versus a 29"er tire is quite different. The WTB Trailblazer is a squared off, "all tread hits the trail" tire where a 29"er tire typically will not do that. Yes- the Trailblazer has a continuous center strip to help against this, and it works, but you will feel the "all the tread-all the time" rolling resistance and especially at lower pressures. Finally, that squared off profile and close tread block pattern makes the Trailblazer a drier conditions tire. Mud will send this tire skittering sideways. It also doesn't have a ton of side bite, but in drier conditions this is okay, in my opinion.

This single speed mid-fat set up is a blast to ride.
Conclusions So Far......

I will likely try the Fargo Gen II with the rigid fork, but in the end, I think I am pretty sure where this whole experiment is going to go. I've tried these wheels on four bikes now, and two of them were instantly inducing smiles, while the other two were head scratching conundrums and have not produced the "fun factor" the other two have. Interestingly, the two fun set ups have both been single speeds.

The lighter weight of a single speed bike overall can allow for heavier wheels and momentum, while not at the levels of a 29"er, are still pretty good with the mid-fat wheels. And we all know momentum is king with regard to single speeding. Add in the extra traction, a bit easier spin up than a 29+, and extra cush, and it all adds up when one gear is used. Why that hasn't translated to a geared hard tail set up has been baffling, but the differences in feel are like night and day to me.

The Industry is going to go "ga-ga" for these mid-fat wheels and I suppose with some quality rubber, it may be an okay deal for some. However; I am not seeing a super-wide ranging appeal here from my point of view. Ride a 29"er most of the time, and where conditions get sketchy, looser, and you want to push out your boundaries, go all in and ride a fat bike. There is one wheel that maybe will yet change my mind and that's the 29+ deal. I tried it on two different rigs. One was an amazing experience, and one was so-so, which leaves me at an inconclusive state where 29+ is concerned. I will be researching that more as time goes forward as well.

Stay tuned.......

3 comments:

Barturtle said...

So, coming at this from the dropbar, gravelly side of things, and having no bike more trail capable than say your BMC Orange Crush (so no Fargos or MTB or fatbike in my stable) but looking to get into trail riding and bikepacking, can you see a reason to not look at one of the B+ bikes coming out instead of a 29er or 27.5 trail bike?

Guitar Ted said...

@Barturtle: No, to be blunt. Not if you are going to stay on gravel mostly, and a qualified "maybe" if you are riding trails. I only see the B+/mid-fat wheels being a big advantage on rough or sandy/loose trails where a bit of flotation might save your bacon. Otherwise, 29"ers with sturdy wheels and lighter tires running tubeless have proven themselves on bikepacking trips all over North America with little downside.

I, for one, would rather have the lightest set of wheels and tires I could get away with on a bike with a load. If conditions warranted bigger, higher volume tires with flotation, then one has to start looking in the direction of 3.8"-4.0" fat bikes. The wheels and tires are marginally heavier than B+/Mid-fat but are far, far better at flotation and grip.

As I stated, the only outlier, for me, in all of this is 29+, which has more fat bike-like qualities for sure than 27.5 based mid-fat tires do. At least from what I've witnessed and experienced. I'll be posting more on that later this Summer.....

evan said...

Thanks for the research Ted, Im seeking to replace my stolen fargo which I rode to work 5 miles one way daily for 2 years. Im also planning a small amount of bikepacking in early fall. While I have a rip9 for dedicated singletrack/bikepacking, It doesnt do commuting. I liked the do it all-ness of the fargo, and spontaneous summer trail rides with my fiancee.

On snow-mank days, Ive been commuting on a 26x3" beach cruiser which is geared high for snow but provides adequate float and rut forgiveness. The cruiser is also a single speed, with a grimy, unsealed one piece BB.(If the 1" headset survives winter it may get a 'sealed' one piece BB, 2 spd kick back hub, and a tiny chainrig. I suppose I could purchase all of the above and a new cruiser for the cost of a naked pugsley frame, and keep a normal BB width.

While seeking a quality all-weather workhorse commuter, I and am entertaining an internally geared Fargo, ECR, Pugsley, etc build, but the market options and non IGH friendly dropouts are inducing commitment issues-Maybe Im crazy/outdated to have high expectations of a $2K bicycle-especially when it resembles greater theft appeal, and similar durability and maintenance as the $100 1986 schwinn mirada Ive been riding daily for a year?

-ECR looks great, but the BB drop at 80 mm seems low for running non-plussed wheels in summer (Krampus has a higher BB, but is too typical of Surly's-90's xc race geo for me. The fargo is proven, but the frameset only offers a carbon fork-an expensive no go for daily bike rack parking. The pugsley seems suited to most any wheel, but I'm hesitant to invest in the wide BB without intention of exceeding 3" tires. With the cost of factory framesets approaching $1K, maybe its time for a handbuilt ECR frame, and factory fork? I'd appreciate any suggestions or references. Anybody want to sell a large steel sliding dropout fargo frame for $500.....I didn't think so, but had to ask.