Why are the e-bike sold only with heavy inefficient fat tires?

[Elkman]

I have traveled thousands of miles on conventional human powered road bikes and fatter tires take a lot more energy to move down the road and I would have thought that a eBike that is going to be used on the pavement would have a narrower tire to get more speed and more miles per charge. What am I missing?

Weight is also a concern as the eBikes seem to weigh 55 to 65 lbs with the battery and 50 to 60 lbs without the battery. A normal folding bike weighs in at 25 lbs and so I am wondering where the extra 25 to 30 lbs goes. Does the motor weigh 30 lbs as that is hard to fathom.

 

[Nova Haibike]

What am I missing?

It has puzzled me as well. Fat regular bikes were a fad that came and went, but I guess the motor changed the dymanics of the equation; the motor makes up for the inefficiency. I think it is mostly a North American phenomenon, where bikes are still primarily a toy.

 

[Stefan Mikes]

Why are the e-bike sold only with heavy inefficient fat tires?

Nothing more wrong. You must have looked at budget e-bikes popular among a certain category of mostly North American e-bike riders. While, there are all imaginable classes of e-bikes out in the market:

• Super-lightweight e-bikes (road, MTB, commuter). For instance, a high end model of Specialized Creo SL road e-bike might even weigh as little as 26.9 lb
• Road e-bikes on narrow, slick tyres
• Gravel e-bikes with somewhat thicker (but still narrow) tyres
• Hybrid e-bikes (all-rounders) with, say, 1.5" tyres
• Commuter e-bikes with 1.75-2.4" tyres
• e-MTB on tyres ranging from 2.2-3". By no means it is called "fat tyre". These are "off-road tyre" e-bikes, often with full suspension.

I'm sure I managed to miss some more categories. If we put the super-lightweight e-bikes aside, a typical e-bike of the categories I listed above would be 46 through 53 (most typical figure for a mid-drive motor e-bike) to 59 lbs. Don't, however, expect paying $2000 for any of them.

So, it is your choice to select e-bike of a category that fits your needs, with the appropriate tyre size for the purpose. Regarding the weight, the motor easily offsets the bike weight, even at low pedalling assistance. Only in case you need to carry your e-bike, you might want the super-lightweight variety.

You asked why e-bikes are so heavy. If we take a typical budget Chinese made, stamped, fat tyre e-bike with a hub motor, the hub motor is very heavy. Additionally, owners of such e-bikes love having extremely powerful motor & the throttle (because it is hard for them to start the ride without massive motor assistance). That calls for a very heavy battery. For typical higher quality mid-drive motor e-bike, I might quote the figures for my Specialized Vado 5.0 e-bike (the Euro Speed version):

• Battery weight: 6.6 lbs
• Motor weight: 8.6 lbs
• Total e-bike weight: 53 lbs
• Net bike weight: 37.8 lbs.

Don't tell me a regular traditional commuter bike weighs less than 37 lbs (Additionally, e-bike must be sturdier than the trad bike because it needs to be strongly built to be able to carry not only the rider but also the motor and the battery).

 

[theemartymac]

And fat tires are more forgiving for the casual rider or commuter as well. Anyone can hand pump 20psi. You can't hand pump 80+psi with an economical compact hand pump. Fat tires perform very well in the wet, light snow, even a tiny bit of ice. Most sand and light mud also provides very little problem. You can overload them quite significantly without major safety issue as well. They dampen vibration extremely well, and they handle variable terrain better than a typical skinny tire.

You are right that the efficiency is often not worth the trade off for conventional bikes (outside of winter commuters or heavy haulers, etc), but the motor easily compensates. Above 30 kph, the wind resistance on an upright bike quickly starts to become as big a factor as rolling resistance anyway, so there is little value in tuning the tires for 10% better rolling performance when the rider position is creating 90% of the drag.

 

[Stefan Mikes]

@theemartymac: Well. I can ride through deep sand on 2.6" aggressive off-road tyres with no problem on an e-MTB that weighs 53 lbs. I can even ride through the same on 1.75" Smart Sams, with some difficulty but I can. Why fat tyre? How many of us ride a morass or deep snow?

 

[theemartymac]

@theemartymac: Well. I can ride through deep sand on 2.6" aggressive off-road tyres with no problem on an e-MTB that weighs 53 lbs. I can even ride through the same on 1.75" Smart Sams, with some difficulty but I can. Why fat tyre? How many of us ride a morass or deep snow?

For the same reason people buy 4wd SUV's and Jeeps. Not because they need to do that every day, but because they feel better believing they CAN do it whenever it pleases them. lol

And I have a garage full of bikes from road to MTB to purpose built downhill bikes, and my fat tire e bikes are by far the most versatile with the least effort and skill required. An experienced rider will certainly enjoy the more highly tuned conventional bikes as they can squeeze out the last bit of performance (and appreciate the refinement), but if i'm lending a bike to a casual rider, It will always be the fat bike first. Everyone comes back with a giant smile and good experience.

 

[Stefan Mikes]

with the least effort

4" wheels pedalled with least effort? Heheh.

 

[theemartymac]

4" wheels pedalled with least effort? Heheh.

In assist mode, yes. Even PAS level 1 completely eliminates the resistance of the fat tires, and make the bike feel just as light and responsive as the others. My mothers ebike by comparison has nice 2" hybrid tires, and with light assist it doesn't feel any smoother or lighter/quicker than my 4" tires. I think that really is the appeal of them on ebikes.

 

[Stefan Mikes]

I'm sorry. I thought you were talking trad fat bikes. My fault.

 

[kmccune]

This other poster said a lot. FTs are going to add more resistance, , now for an in shape low weight rider they will not bother them as much if the tire pressure is not too low.

 

[percymon]

Fat Bikes have their place..

they have a certain style
the tyres can add some pliancy to the ride (esp on solid fork framed bikes built at a lower price point)
they can be ridden with less drama on soft surfaces like sand

they didnt really make it in analog form, they were OK for short trips but tiring for longer use.


The electric addition makes them more appealing, easier to ride and can go longer distances if needed. They will never appeal to those wanting to cover 25+ miles per day, so the inefficiency of the tyres really isn;t that big an issue

 

[AHicks]

I wanted to try 4" tires on the bike I purchased recently for their ability to float on top of the sand I have to occasionally traverse here in Florida, but even more importantly is their ride. With 1600w of power available, and a 19.2ah battery to power it, I'm not real concerned about range.

I will say though, the 26x4" tires will turn any bike into a 29'er! They're pretty big bikes!

 

[CodyDog]

Typically the higher end bikes will choose superior material and components which make for a lighter bike.

I will say though, the 26x4" tires will turn any bike into a 29'er! They're pretty big bikes

Not even close!

 

[rich c]

In assist mode, yes. Even PAS level 1 completely eliminates the resistance of the fat tires, and make the bike feel just as light and responsive as the others. My mothers ebike by comparison has nice 2" hybrid tires, and with light assist it doesn't feel any smoother or lighter/quicker than my 4" tires. I think that really is the appeal of them on ebikes.

If the fat tires don’t offer more resistance while pedaling and are effortless to ride, it must have been the geometry of the Sondors I rode with 4.9” tires. That thing was a miserable ride compared to even my Haibike Full Seven with 2.4” tires. The gyroscopic effect of those fat tires made it feel like steering a barge. I had 1,600 miles on it when I bought the Haibike. I only added another 100 miles to the Sondors over a year. I hated riding that fat bike after that and will never own one again.

 

[kmccune]

Typically the higher end bikes will choose superior material and components which make for a lighter bike.

Not even close!

Check the diameter, not the rolling resistance.

 

[kmccune]

I'll bet the Sonders could have been made to float with reasonable size outrigger pontoons( sorry I didn't do the buoyancy formulae)

 

[AHicks]

If the fat tires don’t offer more resistance while pedaling and are effortless to ride, I must have been the geometry of the Sondors I rode with 4.9” tires. That thing was a miserable ride compared to even my Haibike Full Seven with 2.4” tires. The gyroscopic effect of those fat tires made it feel like steering a barge. I had 1,600 miles on it when I bought the Haibike. I only added another 100 miles to the Sondors over a year. I hated riding that fat bike after that and will never own one again.

One thing I've learned is that even just a pound of air pressure can make a very noticeable difference in fat tire ride/handling. Good pressure guage that can pick up a pound of difference (or even a fraction of a pound) is important. Digital gauge is a good plan here!

Granted though, 4.9" is getting pretty big. FWIW, I did change out the original knobby style tires for a street tread, and I think those 4" tires are amazingly light - as are the rims they mount on. Struggle to imagine how much gyroscopic force is being generated at the speeds most of us would be ridding a fatty. That's me though, -Al

 

[Haystacks]

Surprise surprise sneering again eh stefan. Shame i didnt see this before i went out on a ride, i would've taken more pictures and done a video, but a funny thing did happen, i had a DH race with a guy on a turbo vado, and whilst he was cagily picking his way down the trail trying to catch up i was sat at the bottom having a coffee taking this pic of my bike on a bridge, took him 5 mins longer to get to the bottom PMSL.

Why don't you just admit it, you like fat bikes but cant talk the missus into letting you have one.

 

[alloo]

Why do you need lighter components on an ebike? You need more durability since you ride more and longer. I've been ebiking for a two years now four seasons. I'm sick of chain and cassette replacements. My next ebike will be belt driven. I commute so I don't care about weight, I care more about durability and ability to work in the elements.

 

[CodyDog]

Why do you need lighter components on an ebike? You need more durability since you ride more and longer. I've been ebiking for a two years now four seasons. I'm sick of chain and cassette replacements. My next ebike will be belt driven. I commute so I don't care about weight, I care more about durability and ability to work in the elements.

Lighter and more durable go hand in hand with most group sets.