Fat Tires Are Less Stable!
This article may look familiar. It is so important it bares repeating and updating.
Because of inherent danger, I will no longer be offering conversions or factory fat tire e-bikes. If I felt it would carry any weight, I would report these problems to The Consumer Products Safety Commission.
Four of the eight fat bikes I have converted have landed their owners in the hospital. A fifth had a less serious spill that could have been worse. He no longer rides his. Of the three major crashes, all were experienced cyclists on top quality, class I bikes. Each had significantly better brakes and a more responsive frame than you will find on a factory e-bike. One was an experienced motorcyclist as well.
I need to preface this article with three important facts…
1.) Bicycle tires need soft sidewalls. Absolutely nothing that applies to low profile, stiff sidewalled, automotive or motorcycle tires, applies to bicycles.
2.) The wider the tire, the slower you go, for the energy expended.
3) Fat tires are anything 3.5″ or wider. This article has nothing to do with fattER tires, but actual fat tire bikes. Note: 20″ fat tires have a stiffer sidewall just because of their wheel size. Everything written here is somewhat muted on 20″ fat tires.
When you fill a fat tire with enough pressure to be efficient as an e-bike, it bounces like a basketball over road irregularities. If you run them at lower pressure, they aren’t efficient, they dive in stopping and squirm in cornering. I have even had them burp off the rim hopping curbs. If suspension is added, these problems can be multiplied!
Somewhere along the way we got sold a bill of goods. Someone that probably knows electrical and nothing about actual cycling, convinced us fat tires are more comfortable and “look tough.” Yeah, you gotta be tough to pedal them and you need a giant battery to get any e-bike range out of them.
There’s a reason fat tires have fallen out of favor with traditional cyclists. Those same reasons sap batteries and compromise handling on an e-bike. This does not mean they aren’t great fun in soft sand (not sand on pavement), new fallen snow (not packed), tall grass and plowed fields. They are great for hunting, fishing or even camping, if you can afford to use them for these things only. Most people expect their expensive e-bike to do just about everything.
When mtb’s first appeared commercially in the late 70’s, I thought, “wow, no more flats!” Little did I know that, except for the knobs, wider tires have thinner rubber. If they didn’t, they’d be too heavy. So, now you have a thin tread riding on soft sidewalls that are even thinner. What could possibly go wrong?
Even on 50’s era balloon tire bikes you notice they dive when braking. This extends braking distances. You’ll notice they aren’t as responsive in tight manuevers, which leads less experienced riders to over correct. When the bike does respond it is quite abrupt! So. If you are legally riding along the bike path at 15mph and you need to make an evasive manuever, your fat bike dives, your tires squirm from under you and the suspension collapses. All throw you over the bars and probably into whatever you were trying to avoid.
One of those folks with whom I corresponded had crashed bad twice on his first ride. Doing so, on an e-bike, meant he went down at a much higher speed than most beginning or returning traditional cyclists. High speeds, even higher average speeds, have greater consequences.
Fat bikes were designed to be ridden at 6-8mph. One might occasionally ride a fat bike at 10-12, but not for long. With e-bikes, it is not unusual at all to take these bikes up to 15. 20, even 28mph! You might not think of this as fast, but remember, a fat bike is heavy! It wasn’t meant to be ridden fast and it certainly wasn’t meant to be ridden at tire pressures necessary to be efficient on pavement.
This brings up another myth. Fat tires do not handle slush and ice well at all. Soft, new fallen snow, amazing, but you don’t want your tire to float, glide or slide on packed snow, ice or slush. You need it to cut through or stay perfectly planted, not moving! Stiff sidewalls would help, but they’d be heavy and rough riding.. Weight saps range on an e-bike and thighs on traditional bikes. Fat tires go slower.
You can accomplish the goal of heavy suspensions and fat tires with better geometry. Gazelle, the largest bike mfg, in the most bike friendly country.in the world (one of the world’s largest e-bike mfg’s), does not offer any bikes with tires wider than 2.25″ (even those only in The U.S.)! Their bikes are all about comfort. They don’t worry about going fast. They’re commuting and carrying groceries. If fat tires made sense, they would be leading the way with fat tire bikes.
You might not think you look as cool, but a step through frame is a good start. More upright Dutch geometry, a cruiser (their wider tires tend to have stiffer sidewalls) any foot forward or recumbent bike will be comfortable and more efficient. I am not a fan, but 27.5″ wheels and up to 3″ tires, on a rigid or front suspension mtb would even be significantly better.
Even with thinner rubber, fatter tires are heavier. They need wider rims and thicker, longer, spokes. They require more robust frames . They just aren’t as easy to handle. The second person I spoke with got tired of trying to manuever this great big bike in order to haul it somewhere she felt it would be safer to ride (she’s not enjoying desert foot hills or river sand). That extra weight isn’t easy for a small person to manage at every stop either (it doesn’t help that the frame is so wide and long).
Don’t get me wrong. Wide tires have their place. On gravel, 40c-2.25″ tires rule. Off road, up to 3.5″ on mtb’s.
Fat bikes can be awesome in flat, off road conditions.. Nothing cuts through a field, rolls over sand, plowed earth or fresh snow like a fat bike. They just don’t belong on pavement or even hard pack.
Please, if any bike does not look like the traditional bike you would choose for that same ride, it is not the right e-bike for you.