f you are on the flat, then no, that statement defies the laws of physics.

Unfortunately the world isnt frictionless, so once the motor is off, the effect slows the bike. Yes ?.
So then, i either allow the speed to drop below 15.5 and start the motor again by peddling, or im trying to propel a 52lb bike.

@Thols2
Please troll elsewhere.
I was looking to save some weight, a reasonably thought on the matter but you’re just making a meal out of it.

1. go for a poo before you ride
2. take off the massively heavy motor and battery and save 20lbs or whatever it is that makes a bike weigh 50lbs

“ Unfortunately the world isnt frictionless, so once the motor is off, the effect slows the bike. Yes ?.”

Only if you can’t pedal hard enough to keep the bike moving at constant speed. On the flat it doesn’t take any more power to keep a 55lb bike moving as it does a 25lb bike, if they have the same tyres and aero.

Lots of people think ebikes are unrideable without the motor to help. This is absolute rubbish. It’s like saying that if you gained 2 stone you’d be unable to ride a bike. Yes, it’s a bit harder when you’re going uphill but it’s really not that bad, and on the flat or downhill it makes zero difference.

On the flat it doesn’t take any more power to keep a 55lb bike moving as it does a 25lb bike, if they have the same tyres and aero.

That’s quite true, but a 55 lb e-bike will probably have big grippy tyres and most riders are probably not much into XC and climbing. Having 250 W available to take care of tyre and aero drag will be a shock if it’s suddenly removed. I had a mate who had a freeride bike with 3″ Gazalodis 20 years ago. You had to pedal that thing downhill on road to keep up with XC bikes that were just freewheeling, the tyre drag and aero were so terrible.

Lots of people think ebikes are unrideable without the motor to help. This is absolute rubbish. It’s like saying that if you gained 2 stone you’d be unable to ride a bike. Yes, it’s a bit harder when you’re going uphill but it’s really not that bad, and on the flat or downhill it makes zero difference.

Im not saying or implying its unrideable, im just saying for me its more effort, which I know myself is down too fitness and my vascular condition in my right leg.
But as to the premise about a 50lb bike over a 25lb bike, thats not correct in that were you to multiply the weights to as 200lb bike, or a 15lb bike, would they require the same effort or more/less, which is probably why road bikes arent 50lb 😉
Obviously the lighter bike requires less effort, which is the entire point of thought of trying to drop a kg or 2 off the weight of an ebike, given ebikes,unless you A.spend more, or B. opt for less range and the smaller battery, carbon frame etc are a heavy type bike

Because I put on more road orientated tyres?

No, it’s because what you actually needed was a city bike but despite multiple threads in here and other sites, you couldn’t see past a longer travel full suss mtb for riding to the shops about Glasgow. Now you’re trying to change things to make up for that.

“ Unfortunately the world isnt frictionless, so once the motor is off, the effect slows the bike. Yes ?.”

no, friction from the tyres is not dependent on the weight on them.

*Within reasonable limits so that the tyre has the same profile when loaded. This probably corresponds to about 1 extra psi in this situation.

Obviously the lighter bike requires less effort,

Only on climbs. On the flat, it’s tyre drag and aero. Big DH tyres with soft rubber will be heavy rolling, but aero drag is the big thing on the flat if you’re running sensible tyres.

For steep climbs, it’s basically power to weight because you aren’t going fast enough for aero to be a big effect. For a 65 kg rider with a 10 kg bike, knocking 1 kb off the bike weight will improve power to weight ratio by a bit over 1%, which is a big gain if you’re racing at the pointy end. For a 90 kg weekend warrior carrying 5 kg of snacks and gear, riding a 25 kg bike, a 1 kg saving is less than 1% off climbing times. Ditching a dropper post to save weight will save you a few seconds on climbs but cost you minutes on descents.

If you want to go fast on a bike, starve yourself until your ribs are showing and spend two years riding 200 miles per week with lots of big climbs. Or just buy an e-bike and don’t worry about weight.

But as to the premise about a 50lb bike over a 25lb bike, thats not correct in that were you to multiply the weights to as 200lb bike, or a 15lb bike, would they require the same effort or more/less, which is probably why road bikes arent 50lb 😉
Obviously the lighter bike requires less effort, which is the entire point of thought of trying to drop a kg or 2 off the weight of an ebike

remember that (unless you are in fact a ghost) you need to look at full system weight – include youself. You plus bike is going to be 100+kg. Saving a kilo is a ~1% gain.

There is a long running theme in the mtb world of attributing characteristics to the wrong thing:

I had a mate who had a freeride bike with 3″ Gazalodis 20 years ago. You had to pedal that thing downhill on road to keep up with XC bikes that were just freewheeling

this is correct.
But that freeride bike probably also had 180mm travel front and rear, and a slack (for its age) head angle.

Some people then start spouting bullshit for example that a slack head angle makes the bike slow.

Which is why until recently xc race bikes handled like poo, all mountain bikes had to hit an arbritary weight cap which meant downspeccing vital components, and so on.

No, it’s because what you actually needed was a city bike but despite multiple threads in here and other sites, you couldn’t see past a longer travel full suss mtb for riding to the shops about Glasgow. Now you’re trying to change things to make up for that.

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Yes.
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And no.
A shopping orientated bike, often weighs the same and in a lot of the models I looked at, especially the higher end weighed more, in face 29kg was one ~and i couldnt see how they came to that, given its a lower end fork. But then the lower end and lesser quality components often weigh more, for example a suntour coil fork, weighs in about 6lbs.
But its also to do with having nicer things, which is something many people tend towards.
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A purely shopping only affair, is lower end but not far of similar money, so subtract the ‘retail’ costs of those components and the ‘profit’ margin of the entire set up is considerably more.
Plus the shopping/town bike(of components few here would have high on their shopping list) is fit only for that style of riding. Yes ?. there are no other options you could use it for. its just not fit for it and the lower end componentry will suffer, probably needing replaced more if used for that type of thing. Thats bad economics, especially if like me youre on a smaller income.
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So with a finite amount to spend,and a great knowledge of components from over the last 30 years of building bikes- this being about my 22 or something, its unlikely I’ll choose the lesser over the better spec.
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Then you could add in personal tastes, wants, plus I reckon the fact i was homeless for 5 years, went through the social work system,units etc and had nothing whatsoever, to build up to enjoying the finer aspects of life.
For many its a nice house or what appears to be more prevalent a high end car, not a small cheap runaround suitable for town use, so there the same aspects apply. Why would anyone want to own a car that ,yes can be used to get the shopping in, take the kids to school etc etc but costs twice or three times as much.
I take it youre a driver, im not, ive got one bike to choose from and I’d much rather have one I can adapt to suit a range of tasks that something singular in use and design.
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Ebikes are heavy, pretty much all ebikes(except as covered previously, less range etc etc) and i see no difference to me wanting to reduce that weight, than i have witnessed regular and enthusiastic cyclists do over the last X amount of time.
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Im 6’3″, and 14 1/2 stone, spent a life on 26″, which to be honest looks a bit undersized, even the larger frames, a bit disproportional as you’ll no doubt agree. 29ers have always been touted as a better proportional system for taller riders, so a 29er it was going to be. lus ive not really had a decent proper full suss, so I wanted one of those too.
A suss bike, any suss bike the important parts as the suspension fork and shock, you agree ?. So what opt for those important parts to be lower end, less functional,have less ability etc.
So to get something capable, in my size and all round requirements I need to choose something that contains those elements,and currently I cant buy it all as an individual parts and build it as best suited, or Im throwing good money after bad.

So the bike I’ve chosen, is high end, though full sus ebikes can and do go up to £12000, but fulfills my needs due to medical grounds of assisting me ride easier with less effort and capable should I want to ride the town, the hill or just enjoy riding something of quality.
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As to shopping. I eat fresh food and shop near daily, so its not like im out for foodstuffs for a family of 4 with a weeks supply. couple of days worth and get there with ease.
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But all this apparently appears to trigger some people. I suspect thats more to do with them than how i chose to ride or what i decide to do it on.
Started off ok, dropper is ideal and a few questioned the need to lose that, though it can be refitted if i go further afield, but then the fannies all seemed to come in all indignant about my choices.

Ok,time for plan B H ,that’s H for O o O o o Holes.

Drill everything 🙂

That’s all well and good Dyna, but you are still confusing need and want. If you want all those things that’s your choice and your money, but you do have to accept it will have compromises for the majority of the time you use it.

Drill everything

Yep. If it didn’t work, the pros wouldn’t be doing it.

Do ebike motors have any drag past the 15mph cutoff?

i.e. is there some stuff inside the motor that has friction when the motor is not running or is there a magical frictionless clutch?

i.e. is there some stuff inside the motor that has friction when the motor is not running or is there a magical frictionless clutc

Some of the older motors had a noticable amount of drag , but the modern motors have virtually zero drag from the motor, I think most use one of these

https://en.wikipedia.org/wiki/Sprag_clutch

If you take the chain off a modern ebike and turn the cranks by hand its pretty similar amount of effort to turn the cranks on a normal bike with the chain off.

That drilled BMX gives me the bad fear

I road an ebike up the road hill towards Hawshead from the Ferry across Windermere with the motor off. It was a very heavy ebike and i pedalled as hard as i could. My conclusion was that it was kind of like ridding with panniers. It feels really hard but actually you can still make good progress. I beat my brother in law who was riding my much llighter fs mtb, i was quite surprised. Strava says he is way faster than me on the road

Do ebike motors have any drag past the 15mph cutoff?

I was actually meaning drag as in the extra weight i have to propel without the motor and the effect that has on the legs. Probably not the best choice of words maybe 😕 seems to be confusing the issue.

but you do have to accept it will have compromises for the majority of the time you use it.

Yeah that would be the weight I’ve got the audacity of stupidly trying to reduce 😆
My bike Scott Genius 920- 23.40kg £4899
Shopping/city bikes I considered –
Cube Kathmandu HT – 27.1kg £4299
Cube Hybrid/tour exe HT -26.9kg £3100
Focus Aventura 6.9 HT – 23.10kg £3999
Scott Axis eride FS – 26.60kg £4899
Scott Axis eride HT -25.90 £3499
As you see the majority of the above are heavier. As to outlay, id rather pay more for better spec, and the spec on most cant be compared to the genius)
There are a few others but it was a similar vein, heavier and poorer spec.

If you take the Scott Axis FS, this was my first choice. The frame is identical(geometry etc etc), the suss bits are suntour XCR34 and an Xfusion shock and very little difference on the rest. Yet the same money.
Despite what others might think, I reckon I picked the best,with the best spec for the outlay I was prepared to spend.

This is not a ebikers are fat jibe…but the easiest kg you are going to lose is the one currently around your belly.

You are using this bike for shopping (odd choice, but you clearly thought it through and it’s yours to make) – buy less food & it’s a double win. Less food to carry back from the shops and (eventually) less weight on the waist. AND this method actually saves you money rather than costing. What’s not to like?

If you are not actually racing, the only reason to save weight on a mountain bike is to be faster up hill, and er, that’s what the “e” bit in ebike is for already no??

Personally, i build ebikes as heavy and as solid as possible, esp wheels & tyres and drive train stuff, that way you can still ride on the 15mph limiter up all the hills, but you can now smash down them without breaking anything……

Ride a bit slower then you won’t get past the speed limit. 🙂

Don’t mean to pile on but it is a bit of an odd post. You’re over-thinking it, IMO. Just ride it more then it will get easier/feel lighter.

The only ebikes I’ve tried were lumbering beasts and it didn’t bother me at all, the only concern would be if the battery ran out.