Which bike will completely replace my car

[Ross Outhwaite]

So would any ebike hit top legal speed if I provide 100 watts of power on 5% hills? If I can do 20 mph on the flat reasonable easy I might just get fitter and use my normal bike.

 

[anotherkiwi]

Yes. I managed legal cut off speed up this hill with my hub motor bike at age 61, I am quite fit with strong legs. 3.8 km long and 2.3 km long with bits over 15% coming back up the steep side. I calculated that I was providing over 120 W to achieve that speed.


You sound like a strong cyclist, you should manage. But... Forget about the no sweating bit of e-biking, you are going to be providing serious Watts, this is real sport! I don't think your desired average is realistic but hey, surprise us. Good news you will go faster downhill because of the extra weight of the bike!

Tips:
- always be in the right gear even with a hub bike
- ride at just under the cut off uphill to always have some assistance, say 23 km/h
- cheat... set the cut off to maximum motor speed which is about 32-33 km/h with your typical hub motor. You will be using lots of battery now so take that into account
- buy a much bigger battery than you think you need, see above

Keep us up to date we love data!

 

[Ross Outhwaite]

Brilliant, any recommendations of bikes to achieve this.

 

[flecc]

Good news you will go faster downhill because of the extra weight of the bike!

Careful, you'll have Galileo turning in his grave!

Acceleration due to gravity is a constant, not weight dependent.
.

 

[anotherkiwi]

This is the one I would buy to replace a car: http://ebiketips.co.uk/content/reviews/electric-city-bikes/giant-quick-e-602

The review is balanced I think because he has a couple of negative appreciations. He is wrong when it comes to the double chain ring which is essential in my neck of the woods.

You add a trailer and/or a couple of panniers for shopping.

 

[anotherkiwi]

Careful, you'll have Galileo turning in his grave!

Acceleration due to gravity is a constant, not weight dependent.
.

We did the feather vs bolt drop in high school physics class too . 1 kg of wood and 1 kg of lead will both reach terminal velocity if dropped from high enough but one takes longer than the other because of air resistance...

 

[Woosh]

So would any ebike hit top legal speed if I provide 100 watts of power on 5% hills?

You and your bike (110kgs) will need 550W to fly up 5% hills at 15mph.
You provide 100W, the bike 450W.

The controller will need to deliver more than 450W/(36V * 0.85) = 14.7A.

The minimum is 15A controller but I think it's sensible to select a 17A controller to have some headroom. Quite a few: the Bosch CX, Yamaha, BBS01 (only 15A though), BBS02, the Woosh Rio can do that.[/QUOTE]

 

[Deleted member 4366]

Careful, you'll have Galileo turning in his grave!

Acceleration due to gravity is a constant, not weight dependent.
.

No it isn't. We've been through this before. Your weight pulls you down the hill and the air resistance pulls you back. You can ignore rolling resistance because it's small compared with these two.The force on you, which provides the acceleration down the hill, is the difference between the two. You have to compare that net force with the mass of the rider plus bike. That ratio will always be bigger for a heavier combination, so the heavier one will accelerate faster and reach a higher terminal velocity than the lighter one.

That's why a ball of lead will drop much faster than a balloon the same size. The balloon can't keep up with the lead even during the first inch of travel. the moment they start moving, the lead will be in front.

 

[Woosh]

so he'll accelerate faster and reach a higher terminal velocity than the lighter rider.

it may depend on clothing.
if a thin 70kgs rider wearing lycra races against you down a 10% hill, I reckon the lycra clad guy will win.

 

[Deleted member 4366]

We're talking about the same rider with a heavier bike, so that doesn't come in to it. Clothing does make a massive difference, especially at speeds above 15 mph.