There’s fat bikes and then there is the “what the hell is that?” bikes. The Phat Phuk really deserves a category of its own as the massive 5 inch actual width tires are like nothing else currently on the market. Vee Rubber decided to release a tire so big that it won’t even fit on almost every factory fat bike in production.
What a great idea.
If you build it, they will come
Like a lot of folks, I got pretty excited when Vee Rubber announced their Snow Shoe 2XL tire. You can imagine my disappointment when it hit the shelves and everyone had a really hard time fitting them on almost any fatbike on the market. After some research on this thread with mtbr.com I realized that there are 3 frames that would take these tires on both the front and the rear. The Bikes Direct FB 5, the BD Lurch (you will need the 120mm BB BBSHD, trust me) and the Salsa Blackborow. There are no front suspension forks to date that I know of that will fit this tire. I didn’t want steel and the steel Lurch weighs in at a hefty 40lbs without the massive 5 inch tires and an electric motor. I’m way too cheap for a Blackborow so I went with the FB 5 2.0 which I got at Bikes Direct for around $800 clams (they are on sale right now for early Black Friday). When it arrived it weighed in at a svelte 34lbs with crappy Snowshoe 4.5 72TPI tires and very heavy 4.9″ tubes. I was totally stoked.
The BBSHD did not give me much of a favorable impression when I first unboxed it and threw it on my Death Trap 2000 road bike build for some speed tests. In the woods however, the BBSHD performed much better. Even with the poor programming that it comes from the factory with, it was more torquey than the BBS02 750W and ran a whole lot cooler. When I was thrashing on the BBSHD the controller never got over 125 degrees Farenheight, even when riding in too high of a gear. The 750W BBS02 in contrast needs be run very fast when it is under high load to keep it from overheating, much faster than you could ever hope to keep up with while pedaling. The BBSHD was able to keep a normal pedaling cadence and still produce a surprising amount of power. It was much more pleasant to ride the BBSHD in the woods and to be able to pedal along all the time. The 750W BBS02 gets up to about 140F pretty easy when is when I stop and let the motor cool, the BBSHD 1000W never got close to that temperature no matter what I did.
So do you need to install a temp probe in the BBSHD (instructional video here)? For normal intermediate singletrack trail riding at only 30 amps I would say not. This motor will likely never overheat at that power level.
The front tire rubbed a bit on the fork on both sides due to irregularities in the tire and lack of clearance. The rubbing didn’t bother me that much so I didn’t take any time to do anything about it as I plan to convert this bike to ghetto tubeless. The Surly ICT fork can fit this tire in the front with a 100mm clownshoe. There are also plenty of carbon forks that will fit the Showshoe 2xl. The rear did not rub, but the chain did hit the tire in the lowest gear. It was not enough to kick the chain off the chainwheel when I was riding, it was just mildly annoying. I’ve heard there is also some rubbing against the seat tube on the Lurch so be aware you might have to grind off a cabling attachment to get the tire to fit right without any rubbing on the rear.
The clearances with the pedal and the chainstay were pretty minimal and I had a hard time getting the crappy steel Bafang chain wheel to mount properly without hitting the chainstay. I ended up having to space the factory chain wheel about 3 mm away from the frame of the bike to clear the chainstay with washers. There were still some chain rub issues, but I dared not go any farther from the bike without a narrow\wide chainring.
Getting the chainring spaced out was also a little tricky. I had to grind off the sides of the washers I had because they were too big then I couldn’t get them to stay in place while I mounted the chainring as they would always turn when I tried to tighten the bolts. I ended up using a hot glue gun and gluing the washers in place and then carefully mounting the chain wheel and tightening it up. It is likely that any dedicated ‘Bling Ring’ for the BBSHD will have some kind of spacer ring to make this job a lot easier as it took me over an hour to figure out how to do something that should have taken only 5 minutes. I’m not the smartest peanut in the turd, but of course, you already figured that out.
It’s good that the chainstay on the drive side is squished flat, as there was only a few mm of clearance on both sides of it for the tire and the non-offset crank arm. The speedo will need to be mounted on the non-drive side and you will have to carefully route the cable on the bottom of the chainstay instead of wrapping it in loops around the chainstay like I normally do. There is so little clearance that there is actually no room for the 5 mm wire on the tire side OR the crank side. I used Velcro One ties which do this remarkably well for this job. The speedo should be mounted as close to the hub as you can so you don’t break it off when you take the tires off for servicing. The speedo will sneak in behind the brake rotor as the chainstay angle is pretty severe close to the axle.
The oversized diameter tires screwed up the gearing ratio, begging for a much smaller chainring than the stock 46T paperweight that Bafang ships you. Have I mentioned how much I hate this chainring yet? Are you tired of hearing me talk about it? I am.
The BBSHD’s secondary reduction gear housing will hit against the chainstay when mounting it keeping the drive unit from going all the way into your bottom bracket. Do not modify your frame or do anything at all really. It is fine, just mount the drive system on as far as it will go. As long as you can still fit the locknuts on the end of the BB that is all that matters. If your frame only allows you to mount one locknut instead of two you should blue locktite the crap out of it before tightening it down really, really hard.
These tires beg to be run ghetto tubeless at extremely low tire pressures like 5-6 psi. I was able to run mine with 8spi on the trail with tubes without getting any pinch flats. I was also able to easily clear obstacles that I could not clear with normal 4.0-inch fat bike tires and a BBS02 hanging down like a cow udder. I really liked the extra inch or so of ground clearance that these massive tires give you.
I was not crazy about the aluminum fork on the FB 5, it was more brutal to ride on than most of the steel forks that I have been used to using which tend to be a little more flexy and forgiving. It was especially bad when compared to the Bluto fork on my Dark Matter build, which I’ve been coddled with for the last several weeks. At low tire pressures these tires work a little bit like having a suspension fork, but are much more bouncy and can be a little unpredictable over extremely rough terrain. They do have absolutely insane traction and feel very much like the Bud\Lou combo, which is not surprising because the tread pattern is almost identical. Smart move Vee Rubber, copy the tread off the best tires in the industry. Glad you finally figured that out.
The Snow Shoe 2XL has about 50% more air storage than a Surly Bud or Lou. This means that in general you can run a lower pressure without risking pinch flats and also that it’s a huge pain in the ass when you have to fix a flat on the trail. You’re going to have to do several hundred strokes with a portable pump to get this thing up to any rideable pressure. Personally I won’t ride a bike in the woods that I can’t just throw on my shoulder and hike out with and 51lbs is pretty much where I draw the line. Not one pound more.
You will need to carry a tube that will fit a 4.9 inch tire to fix flats with. I don’t think that the ultralight Qtubes that I generally use to test tires with are going to cut it with these tires. The tires are just too darn big. If you use an undersize tube you should be aware that a lot of times they are just impossible to patch because the rubber stretches so much inside the tire. If you go ghetto tubeless you will minimize your flats and downtime and I cannot recommend this highly enough. Make sure you use subzero sealant if you are going to be riding in below freezing temperatures, which I already know you will.
The FB 5 is a great platform to electrify as it starts out at a very light 34 lbs for a fatbike. The BBSHD is much heavier than it should be and weighs in at over 13 lbs which is about 3 lbs more than its BBS02 100mm converted counterpart. I recommend a battery in your backpack to try to preserve the singletrack riding experience and keep the bike as light as possible. It is also far more stealthy to do it this way.
If you want to plow through deep powder with this build, which you totally should do, then you will need a lot of power. Deep powder has an insatiable appetite for watts. The BBSHD is a better choice for deep powder than the BBS02 750W because you can run the BBSHD at full throttle (1500 Watts) all day long without fear of it self-destructing. With the BBS02, not so much.
I really liked the matte black paint on the FB 5 although I would have never bought it if I had a choice. It did a great job of hiding all the cabling and the motor and making for a very stealthy ebike.
This build ran me about
- $798 for the FB5 2.0 from Bikes Direct (on sale for Early Black Friday $100 off)
- $799 for the BBSHD from Lunacycle.com (there may be a real nice Black Friday sale coming up, get on his email list, cause you just never know)
- $118 from the Snow Shoe 2XL from the Bikeman in Maine
- $15 a tire to go tubeless
Which means about $1850 without a battery. When shopping for a battery make sure to get a 14S (52v pack) from Paul at em3ev or Eric at Lunacycle.com . You will get a lot more power out of it than you will out of a 13S (48v) pack. No matter where you ship it from, the battery is going to be expensive due to hazmat shipping charges. You should expect to pay at least $500 for a decent 52v battery and charger without the shipping.
Although there are a lot of people who really hate on Bikes Direct I have to say I’ve bought a dozen bikes from them personally and never had a single problem. My good friend Larry Clarkberg has bought a whole lot of bikes from BD to convert and resell as electric bikes in his shop Boxy Bikes and he is also quite happy with them. If you want a cheap bike with decent components there is no one else that holds a candle to Bikes Direct for the price that I’ve found yet. If you must have a ‘brand name’ on your bike or all your friends will make fun of you then spend the extra thousand or three and get a Surly, Salsa or Carver. I’d rather spend my extra money on
drugs and hookers seed garlic and cow manure for the wifey’s garden.
Although I’m standardizing on XT90 connectors now, the BBSHD ships standard with Anderson Power Pole connectors. It’s funny that they are standardizing on such an old and outdated connector. It seems like Bafang is putting all its future hopes into this drive unit, but there are choices that they have made with this unit that seem pretty strange. Limiting the controller to 30 amps? Giant steel chainring? Anderson Powerpole Connectors? Bafang seems stuck in the 90’s.
Instructions for installing the temp probe on the BBSHD are pretty much the same as the BBS02 and can be found in this article here. If this is going to be a road bike and you want to hammer the throttle all the time then you might want to consider it but for normal singletrack trail riding a temp probe is probably not necessary.
The BBSHD makes a decent platform for a fat bike if you take the time to reprogram it. I recommend em3ev’s settings with a few small changes including the Throttle mode set to Speed not Current and then you should lie about the wheel size and set it to 19inches so that the motor will dump more power into the drive train than it really should. This will void your warranty, but trust me, it’s worth it. Programming the BBSHD is the same as programming the BBS02 and this link here will get you started down the rabbit hole.
If you want a snow machine that is completely unlike anything sold on the market and unlike anything you’ve ever seen or ridden, then the Phat Phuk is a build worth duplicating.
We’re all ready for the next step in evolution, bring on the 6″ actual width tires. We’re ready.