Electric Fat Bike Creations

March 9, 2012
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Wide framed, wide tired electric e-bike offer many advantages over slim tired mountain bikes. First is there ability to ride where no one else dares rides…over the beach and through the snow.

A electric motor on a fat bike makes a lot of sense. Usually pedaling a fat tired bike with all that rolling resistance would be a beat of burden, but with an electric motor the resistance of the extra  wide tires is negligible. And the extra tire makes for a sturdier more comfy ride. In general, we at electricbikes.com believe the wider the tire and rim the better for any ebike, not just sand bikes. Check out our article on tire choice here.

The fat tires not only  give the bike an  awesome look, the tires make the bike more stable when riding off road, and they add snow and sand to possible riding surfaces. In addition the bike has more tire touching the pavement so is more stable on pavement when riding a straight line. However wide knobby tires as traditionally found on sand bikes are not ideal for high speed cornering so the street rider should beware.

The first commercially available sand bike was the Hanebrink ebike which we reviewed here.  For riding on soft sand there is no better option than the Hanebrink with its 8 inch wide tires and through the gear motor system. The Hanebrink is able to chug through soft sand in its lower gears and extra fat tires  like no other electric bike ever devised.

Hanebrink Fat Bike

The Hanebrinks are expensive, starting at $6000. And until recently this was the only way to go if you wanted an electric sand bike. The advent of the Surly Endomorph tires and Large Marge wheels changed everything. These tires and wheels would be the basis for the Surley Pugsley bike., which is the first affordable sand bike on the market. Where the Hanebrink non electric sells for $4500, the Surley Pugsley non electric sells for $1500. The Surely Pugsley with its steel frame and perfect triangle frame makes an ideal ebike conversion bike, and a few innovative DIY’s  (author included) have built  their own sandbikes. Others used just the Surly wheels and tires and designed their own sandbike frames such as this custom titanium frame with front wheel drive Crystalyte hub motor:

In the USA there is no laws against riding a bicycle on the beach (because it is rare that anyone does it)….Since federal law considers an electric bike to be just a regular bike and not a motorized vehicle, electric bikes are free to ride on the beach on most US beaches. Riding on the beach on a bicycle is a liberating feeling. On the wet pack, just before the water line, the ride is amazingly smooth and you can hit top speed of the electric motor with no fears of instability.

Riding in tandem is almost always funner than riding alone.

When you ride a fatbike e-bike you feel like you can ride anywhere. Ramrodding across golf courses in the dead of night will feel like floating on air.

Most electric fatbikes (Hanebrink is the exception) do not come with suspension, that is because those thick  tires give you one inch of cushy travel, and it is hard to find a front suspension fork that will fit the 4 inch wheels.

In fact as of this writing there is not any front suspension forks available for fat tired bikes. The only suspension fat tired bike that is available is the Hanebrink, which has custom made front forks.

Some riders including myself have been riding on the beach on regular basis.  One downside is all the attention you get . Riding a fat e-bike down the beach is the equivalent of riding a Red Ferrari down the street., except no one has never seen it before. The other big downside is the havoc the salt water does to your bike. Even with hosing off the bike after every ride, oiling exposed components etc…after just a few months of beach riding my electric sand bike shows many signs of visual rust although nothing has frozen up or started creaking yet. But it is a bit of a heart breaker to see the Surly Pugsley e-bike I spent over $5000 on to build to lose all its polish and sheen. Check it out:

The Surly Pugsley is a steel framed bike so therefore the rust on the frame is easily sited.  The chain is the worst culprit for rust attraction, even though I was diligent about cleaning and oiling it after almost every beach ride. The saddest part in this photo is my beloved $1500 Rohloff which even though it is made of alloys, you can see its nice polished look is well tarnished even though it is less than a year old. You can also see the salt air and salt water is taking its toll on the avid bb7 disc brakes. All the components mentioned, even though visually tarnished, still work perfectly. The other positive news is all the electronics, especially the front bmc hub motor are holding up great. In fact the black bmc motor still looks relatively new. And given how many times it has been splashed with salt water, I am happy it is still working perfectly.

surly electric bike

 

You can see in this photo that tarnish and rust are evident everywhere. The expensive large marge rims are in really bad shape visually. All bolts and fasteners are getting rusted out. But the BMC hub motor, with its powder coat paint job is the nicest looking thing on the bike!  The next step is to actually disassemble the  bmc motor and see how it looks on the inside. Because the bmc is a geared motor, there are many moving parts, and I will be lucky if none of those are starting to rust.

The trick to sand bike riding is to ride on the water line where the sand is wet. Even on an e-bike with fat tires, riding on soft sand is too tough.  With a super  powerful sand e-bike it is possible to ride on soft sand but it is difficult and drains the battery. Also a lot depends on the sand consistency where you are riding.  Some sand is so soft that the electric sand bike will  just sink in it and make even riding on wet sand super difficult.

If you lower your air pressure down to 1olbs it is much easier to ride on the soft sand. But if you are like me and do a mixture of sand and street riding on the same ride, you will have to carry a bicycle pump to pump those fat tires back up…and filling up a fat tire because of their large volume is not a quick task.

If you decide to ride your fat electric bike on the wet  sand you are venturing into unknown territory on what  damage the salt water might  do to your bike. Not many people have done it.  Regardless of what your bike is made of, or what your components are made of it is a good idea to hose down your e-bike with fresh water after every ride. Also experiment with different lubricants for your chain and other exposed metal parts.  If you can afford it, replace all your steel bolts with titanium if you cant stand the idea of rust, also there is a titanium chain on the market but it is expensive (over $200).

I prefer a liquid wax chain lube and apply after every ride. If you research on bike forums etc every one has a different idea on what the best chain lubricant to use is.

Another  big factor is which electric motor you choose. For a sandbike, a hubmotor with its sealed casing is an ideal choice for motor.  Hub motors have been run underwater in tests for days without failure.  I have had great success with both the bmc and the crystallite hub motors riding on the beach. Cheap hub motors will probably not have good sealing and will deteriorate quicker riding in sandy and salty conditions. If

Regarding bicycle components derailleurs  are really tough to keep sand free and rust free on a sand electric bike. Once your chain and driveline components begin to rust (which they will) if you are using derailleurs your bike will really start to creak and be annoying to pedal.  I like to use IGH’s (in the gear hubs) in all my sandbikes, specifically the alfine 8. Because I use igh’s in the back, I prefer front hub motors. Sand bikes have beefy and wide front forks that will accommodate rear hub motor units. Also the weight on the front balances the bike since I usually run batter pack in back.  i like to run hydraulic disc brakes because I dont have to deal with the brake cable rusting. However, while they are still good I use the cheaper mechanical disc brakes that came with the bike, and plan to keep using them until they fail due to rust. I have been running avid bb7’s for 6 months and havent had a unit fail. So even though hydraulics would be a nicety, its also a shame to see nice components rust in harsh riding conditions on the beach.

Also titanium bike frames (like my bike picture) make a lot of sense as sand bikes because they are completely rust resistant.

The Surley Pugsley consisting of a  steel frame will definitely rust if you ride it on the water line, although the rust just seems to be a visual draw back since you don’t have to worry about the frame rusting all the way through, it just doesnt looks as cool as a flawless titanium frame bike.

 

The electrified Surly Pugsley is a fun bike, and should be outfitted like one:

 

 

 

The titanium bike, even after months of sand bike riding still looks flawless...not a spot of rust, and still a beauty queen gleaming in the afternoon sun.

 

Contrary to popular belief, the Fat Bike is just at home on the street as it is on the sand.

 

 

 

with frame battery bag instead of rear mount battery

 

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Eric has been involved in the electric bike industry since 2002 when he started a 6000 square foot brick and mortar Electric Bike store in downtown San Francisco. He is a true believer that small electric vehicles can change the way we operate and the way we think.

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