Lightweight ebikes that can still do steep hills and ride like a regular bike on the flat

[Bogmonster666]

I tend to see a flaming coming but here goes...

I tend to use 2 bikes, an old but quite light analogue hybrid and a TSDZ2 tank like bike. Both work fine, the hybrid is nicer to ride and on gently undulating terrain is much more fun for me - and generally much faster on average than the tank as I'm usually over cutoff speed.

The tank has its uses, I'm tired, have big hills, lots of cargo, little enthusiasm. But on gently undulating terrain it is a heavy tank and whilst I can peddle at 20mph it's hard work and not much fun for more than a few miles. Generally I find 15.5 mph limiting, and being law abiding that's what I stick to assisted.

That's why I'm pleased to see some much more nuanced options coming out. In particular the Bosch SX powered bikes which have much lower torque than much of the competition but with suitable gearing and a fondness for high cadance look perfect for me. This month's cycling uk magazine has a review of a Cube Nuroad Hybrid that looks like one of the few ebikes I've seen that I would consider dropping serious money for. It's not super light at 14.5kg but much lighter than my tank (but still almost 5kg heavier than my hybrid bike). It's got 52t rear to 42t gearing so will get up significant hills, it has minimal drag over cutoff. It's one of the new set of bikes that actuly has a chance of combining the best qualities of my existing bikes. There are other options of course, but the lightweight hub bikes tend to bog down on the really steep hills.

It's nice to see options that better cater for people who want to put effort in, like to cycle fast, but still need help on the very steep hills when the going gets harder without being unduly hamstrung when the going is easier.

If less hilly there is the rather spendy Ribble Endurance line of ebikes at ~11.5 kg, but unlikely to help on really steep hills, with my fitness anyway, as I'd struggle to keep the bike goi g fast enough.

I guess what I want is a bike I'd ride 85% of the time with zero assistance and enjoy, but have assistance on the very steep longer hills for 15% of the time. There are few bikes that meet these criteria.

 

[Bogmonster666]

Yes, I know I could put my TSDZ2 in a much lighter bike without the pointless suspension forks and silly motorbike tires but it would still be a frankenstein. The Q factor would still be terrible and the reliability questionable. I still think the TSDZ2 is the closest yet on the kit market though. Not sure I'd subject a nice carbon framed bike to the fate of a TSDZ2 carbuncle though.

The Bosch SX is 2kg and the TSDZ2 is 3.6kg. There are some lighter mid-drives but not with the same umph as the Bosch. It's going to be hard to get a usable TSDZ2 bike under 15kg and I view that as the upper limit for a nice un-assisted riding experience.

 

[Az.]

Nice read, but pictures and links are missing.

 

[Bikes4two]

Clearly bike aesthetics are a factor for you on this one so I understand the 'carbuncle' term re the TSDZ2.

Like you, I love the TSDZ2 (I have two bikes with them) as these motors allow me to put effort in, considerable or otherwise, when pedalling.

One my bikes is an old school/late 90s Ridgeback road bike (Alu frame, carbon forks) which I stripped of excess encumberances (pannier rack, Carradice saddle bag with excess of come-in-handy tools, etc etc) and fitted some nice roll-easy 28c tyres plus a very discreet 10s, 2p battery in a small handlebar bag.

This to me is a very discrete/stealth arrangement and most of those in my cycle club don't realise I'm electric and I have to point out the mid-motor.

More importantly is the ride - it rides very nicely - obviously there's the weight of the motor and battery (around 4Kg) on the bike and the motor at assist level zero (rather than OFF) does give a low level of 'drag', but on longer rides (around 100Km) I often ride with low or no assistance and typically get between 5 -6 Wh/mile and the bike experience is very close to what is was before I put the motor in.

As for the 'Q' factor on the cranks - the wider dimensions of the TS cranks is for some an issues, but not something I've found as so. One one of the bikes (can't remember which one) I fitted Bafang mid drive cranks (about £20 from Ali Express) which improved the Q factor considerably.

Others in my local club for whom aesthetics seem to be more important, have gone for Boardmans (Fazua) or the Ribble CGR ALe (Mahle X35) both well under £3k and although their batteries are small (both 250Wh) members have no problems on our regular 100Km rides as they are enthusiastic, regular rides albeit like me, pushing on a bit (LOL) and pedal unassisted quite often.

Their bikes are nice examples of low cost proprietary e-bikes, but proprietary non the less.

If you've got the money and fancy a treat, then go for a proprietary system - as a retired electrical engineer with a curiosity for kits, I wouldn't myself be comfortable for spalshing out for something I can build myself .

 

[Peter.Bridge]

Yes, I know I could put my TSDZ2 in a much lighter bike without the pointless suspension forks and silly motorbike tires but it would still be a frankenstein. The Q factor would still be terrible and the reliability questionable. I still think the TSDZ2 is the closest yet on the kit market though. Not sure I'd subject a nice carbon framed bike to the fate of a TSDZ2 carbuncle though.

The Bosch SX is 2kg and the TSDZ2 is 3.6kg. There are some lighter mid-drives but not with the same umph as the Bosch. It's going to be hard to get a usable TSDZ2 bike under 15kg and I view that as the upper limit for a nice un-assisted riding experience.

1.6kg AKM74 (they do a 36V or 48V versions (with different motor windings) + bag battery

This was a folder, but you get the picture - https://www.pedelecs.co.uk/forum/threads/converting-a-little-folder.47261/post-716610

If the assist is just for hills make sure you get a motor with a lowish max rpm

 

[Bikes4two]

1.6kg AKM74 (they do a 36V or 48V versions (with different motor windings) + bag battery

....... and somewhere for the controller and the hub motor/controller power delivery characteristics will not match those of the torque sensing of the TSDZ2 obviously enjoyed by @Bogmonster666 although a KT controller will go some way to mask the lack of torque sensing.

 

[Peter.Bridge]

and somewhere for the controller

Yep - it went in the battery bag

 

[Bogmonster666]

1.6kg AKM74 (they do a 36V or 48V versions (with different motor windings) + bag battery

This was a folder, but you get the picture - https://www.pedelecs.co.uk/forum/threads/converting-a-little-folder.47261/post-716610

If the assist is just for hills make sure you get a motor with a lowish max rpm

Msybe my calculations are off but a 201 rpm motor in a 700c wheel gives about 16mph. Obviously you can run the motor slower but I imagine efficiency falls off rapidly.

I rarely need help on say a 12% hill but start to struggle over longer hills over 15% (and I live on such a hill which is 16%+ in places). If I'm fresh I'm OK, but after 30 or 40 miles the hill is hard work coming right at the end of every ride.

I don't think a small motor like the akm75 will happily haul me up a 16% hill even if I can put in modest effort.

And that is the crux, when I really want help the most, I need something with adequate grunt to get the job done. I'm happy to climb slowly, but I've found few small hub motors that will be happy unless they are in clown bike wheels. A 65nm behemoth will get the job done but that's moving in the wrong direction weight wise.

That's why a light mid-drive with low gearing works for me. If the gearing is low enough I can puttle up at a brisk walking pace. That's why motors like the Bosch SX are attractive. They don't have the raw muscle of their bigger brothers but not the weight either.

Here is one of the many reviews: https://flowmountainbike.com/tests/bosch-sx-motor-review-e-mtb/

There are slightly lighter systems like Fazua, but the Bosch does appear a more rounded package.

 

[guerney]

I don't think a small motor like the akm75 will happily haul me up a 16% hill even if I can put in modest effort.

And that is the crux, when I really want help the most, I need something with adequate grunt to get the job done. I'm happy to climb slowly, but I've found few small hub motors that will be happy unless they are in clown bike wheels.

I don't know if this is at all practical, or indeed desirable: Put those clown wheels onto something like a Cove Stiffee, and install a lightweight hub motor? Looks like there is enough ground clearance for 20" wheels, and the BB is pretty high, you could chuck a mid-drive on instead.

Cove Stiffee fr | eBay

<p dir="ltr" style="margin-top:0; margin-bottom:0;">Cove Stiffee fr. 2002, 17.5 frame, excellent condition, new BB/drive chain, minor paint wear and tear, many original components including Hope mini's. Will include 3 replacement brake pad sets.</p>

www.ebay.co.uk

Cove Stiffee review
Canadian hardcore hellraiser

https://www.bikeradar.com/reviews/bikes/mountain-bikes/cove-stiffee-review

 

[saneagle]

Msybe my calculations are off but a 201 rpm motor in a 700c wheel gives about 16mph. Obviously you can run the motor slower but I imagine efficiency falls off rapidly.

I rarely need help on say a 12% hill but start to struggle over longer hills over 15% (and I live on such a hill which is 16%+ in places). If I'm fresh I'm OK, but after 30 or 40 miles the hill is hard work coming right at the end of every ride.

I don't think a small motor like the akm75 will happily haul me up a 16% hill even if I can put in modest effort.

201 rpm is just about right for a 700c wheel. 201 rpm is the maximum speed, which equates to 16mph at nominal battery voltage. In practice, your battery is typically around 10% higher on average, which would give a max speed of 17.77 mph. Peak. power and efficiency come at about 75% of maximus rpm, which would be about 13.5 mph. You'd still have good torque and efficiency at around 8 mph, which is perfect for climbing steep hills. I've tested a bike with a 180rpm Bafang hub-motor up my 14% (measured) test hill. It had 700c wheels, a 15A controller and 36v LiFe battery (Kudos Safari). It was dead easy to pedal my 100kg up that hill and it had plenty of power to ride around at 15.5 mph.

AKM 75 is a bit small for we heavyweights to use for climbing, but Q100 has plenty of power, especially a 201 rpm one at 48v. I'd choose the Q100H, which is the freewheel version, so limited to 7-speed gears, but it has tremendous torque for its size and weight, and it's fairly robust.

 

[Peter.Bridge]

201 rpm is just about right for a 700c wheel. 201 rpm is the maximum speed, which equates to 16mph at nominal battery voltage. In practice, your battery is typically around 10% higher on average, which would give a max speed of 17.77 mph. Peak. power and efficiency come at about 75% of maximus rpm, which would be about 13.5 mph. You'd still have good torque and efficiency at around 8 mph, which is perfect for climbing steep hills. I've tested a bike with a 180rpm Bafang hub-motor up my 14% (measured) test hill. It had 700c wheels, a 15A controller and 36v LiFe battery (Kudos Safari). It was dead easy to pedal my 100kg up that hill and it had plenty of power to ride around at 15.5 mph.

AKM 75 is a bit small for we heavyweights to use for climbing, but Q100 has plenty of power, especially a 201 rpm one at 48v. I'd choose the Q100H, which is the freewheel version, so limited to 7-speed gears, but it has tremendous torque for its size and weight, and it's fairly robust.

I think the Q100 is only 2.1kg, I think a 48V 10Ah battery bag is 2.2kg , so start off on a 10kg bike and it comes in at <15kg

 

[saneagle]

I don't know if this is at all practical, or indeed desirable: Put those clown wheels onto something like a Cove Stiffee, and install a lightweight hub motor? Looks like there is enough ground clearance for 20" wheels.

Cove Stiffee fr | eBay

<p dir="ltr" style="margin-top:0; margin-bottom:0;">Cove Stiffee fr. 2002, 17.5 frame, excellent condition, new BB/drive chain, minor paint wear and tear, many original components including Hope mini's. Will include 3 replacement brake pad sets.</p>

www.ebay.co.uk

Cove Stiffee review
Canadian hardcore hellraiser

https://www.bikeradar.com/reviews/bikes/mountain-bikes/cove-stiffee-review

Those sort of bikes are basically unsuitable for hub-motor conversion. It's designed as an MTB with small chainwheel and very low gearing for climbing steep hills. When would you ever use those gears that go lower than 1:1? When you have a motor, the slowest you ever climb is about 8 mph. The 34T chainwheel would cause your pedalling to max out at about 15 mph, which would be useless for riding to work or on a tour. You'd be much better off with a 10 year old bike that has a standard BB, 48T chainwheel and 7-speed gears.

 

[Bogmonster666]

Clearly bike aesthetics are a factor for you on this one so I understand the 'carbuncle' term re the TSDZ2.


I often ride with low or no assistance and typically get between 5 -6 Wh/mile and the bike experience is very close to what is was before I put the motor in.

Aesthetics are not really important, quite like the low rent look. The main reason a 3 or 4 thousand pound bike would not meet all my needs is that I need to leave my bike at various places. It is regularly left at caving huts (relatively safe), outside my local, still quite safe, in town at night while I’m drinking and eating kebab - not very safe at all (although I have taken to locking it under the porch of the police station).

I could justify the cost ‘maybe’ if I would still have it if 5 or 10 years. Not so much if some scroat nicks it in the first couple of months…

I was probably getting closer to 7 to 8 wh per mile on the previous bike but it was an ill-fitting mountain bike with front and rear racks and other stuff. It’s also very hilly around here.

I frequently have cavernous rear panniers stuffed with soaking wet clothes and welly boots and helmets and other paraphernalia to cart about. Caving kit goes on the rear rack, warm and waterproof cycling stuff goes on the front. I’m often heading home at midnight after caving (and pubbage time) and it can suddenly get very cold and wet where I live. At these times I don’t worry about getting more exercise and eking out more miles, I just want to get to bed….

 

[guerney]

Those sort of bikes are basically unsuitable for hub-motor conversion. It's designed as an MTB with small chainwheel and very low gearing for climbing steep hills. When would you ever use those gears that go lower than 1:1? When you have a motor, the slowest you ever climb is about 8 mph. The 34T chainwheel would cause your pedalling to max out at about 15 mph, which would be useless for riding to work or on a tour. You'd be much better off with a 10 year old bike that has a standard BB, 48T chainwheel and 7-speed gears.

That bike might not be suitable for mid-drive conversion either, if the chainstays splay out too close to the BB. Here's 20" wheels and a rear hub motor installed on a trials frame designed for 26" wheels - BB looks higher:

20" wheels on mtb frame?

Seen alot do it...im guessing do to the epic torque? Does the front wheel need to be matched for better handling? How does a 20" wheel do offroad?

endless-sphere.com

This larger photo requires ES account login:

https://endless-sphere.com/sphere/attachments/hubby_motor-jpg.66144/

 

[LithiumFan]

I've tested a bike with a 180rpm Bafang hub-motor up my 14% (measured) test hill. It had 700c wheels, a 15A controller and 36v LiFe battery (Kudos Safari). It was dead easy to pedal my 100kg up that hill and it had plenty of power to ride around at 15.5 mph.

Which bafang rear hub motor has an rpm of 180rpm? I'm not too bothered about reaching even 15mph as I'm most concerned about being able to climb hills at even 5 or 6mph with maybe 100-150w of my own power.

 

[saneagle]

Which bafang rear hub motor has an rpm of 180rpm? I'm not too bothered about reaching even 15mph as I'm most concerned about being able to climb hills at even 5 or 6mph with maybe 100-150w of my own power.

I don't know if it was a Bafang motor. Whatever it was, it was the standard motor fitted to a Kudos Safari.

If you want a 180 rpm motor, you'd have to look on Aliexpress and places like that. 201 rpm motors can be bought from Chinese resellers, like BMS battery. Alternatively, you can take any 48v 230 rpm motor and run it at 36v to get 180 rpm.

For a lightweight climber, I'd use a 36v 201 rpm Q100H at 48v. It's very light and free running, yet very powerful.

 

[Nealh]

Small lightweight motors may not be good for the heavier rider on steeper ascents but with the lower rpm winding of sub 201 I can vouch they are very capable for towing heavy loads on even terrain with modest gradients.
The Bafang G370 though a front motor has proven to be a superb runner for me and has towed over 125kg .
For lighter weight bike then the small hub motors are worth a consideration depending on ones needs and terrain .

One aspect most folks forget is that these little motors have far superior higher internal gearing then the usual 4.4.1 or 5.1 that most hubs have the AKM's and the G370 range from 8.1 to 14.6.1 meaning they ride as easy unassisted as they do with even low assist power.

When I fitted my G370 I was 85kg and had no issues with it , as of yet I haven't ridden with it above PAS 2 level of my 20a KT system , even with towing 90kg loads.
Currently due to my surgery and post op stay in hospital I have lost 10kg in weight and will have lost a lot of my cycle fitness so will be interseting when I am allowed back on my bike in a few months.
Since my surgery I'm not allowed to run , ride , stretch , drive or lift any heavy objects until my consultant surgeon clears me to do ( not even allowed to push a vaccuum around),

 

[saneagle]

Small lightweight motors may not be good for the heavier rider on steeper ascents but with the lower rpm winding of sub 201 I can vouch they are very capable for towing heavy loads on even terrain with modest gradients.
The Bafang G370 though a front motor has proven to be a superb runner for me and has towed over 125kg .
For lighter weight bike then the small hub motors are worth a consideration depending on ones needs and terrain .

One aspect most folks forget is that these little motors have far superior higher internal gearing then the usual 4.4.1 or 5.1 that most hubs have the AKM's and the G370 range from 8.1 to 14.6.1 meaning they ride as easy unassisted as they do with even low assist power.

When I fitted my G370 I was 85kg and had no issues with it , as of yet I haven't ridden with it above PAS 2 level of my 20a KT system , even with towing 90kg loads.
Currently due to my surgery and post op stay in hospital I have lost 10kg in weight and will have lost a lot of my cycle fitness so will be interseting when I am allowed back on my bike in a few months.
Since my surgery I'm not allowed to run , ride , stretch , drive or lift any heavy objects until my consultant surgeon clears me to do ( not even allowed to push a vaccuum around),

That's funny, before you posted that, I was thinking the same about your weight loss. Every cloud has a silver lining. You'll be much faster up the hills now. When I eventually get my gall bladder removed along with all the heavy gall stones in it, I'll be able to pedal up the hills with about 1% less effort.

Let's say you had half your intestine removed, your spleen, gall bladder, one kidney, appendix and tonsils, the weight loss would be quite substantial, so you wouldn't need so much energy to get up the hills. That would mean that you could probably lose a lung too and still get by. I think 25% of body weight might be achievable, and that would increase your range a lot.

 

[Nealh]

Yes will be interesting to see once I get back to cycle fitness, the silver lining as you put it d8veh is yes could prove to be a good one .

It is now ten days since I was discharged from hospital and I have been eating six or seven small amounts daily to give my digestive system time to adjust again, total weight gain is small at 200gms and now I weigh 74.7kg which is a liitle up from the 74.5kg I was in hospital, it is down from my pre op 82 kg and the 85kg I was some months earlier.

For nine days of my hospital visit I was so poorly I wasn't allowed food because of a violent vomiting issue that occurred due to my digestive system shutting down and it kept producing huge amounts of bile, following the first vomiting episode( the digestive system if it can't process food in to waste then produces bile form body fluids) I had a nasal tube inserted and down in to my stomach to drain the bile to prevent me vomiting , anti sickness drugs inserted via my arm cannulas of which I had four for iv drip, paracetamol iv drip for pain relief , antibiotics for my severe lung infection and to ward off sepsis, anti sickness drugs

At it's peak my digestive sytem produced 2.5l of bile over one night and the bile production left me in a serious dehydrated unstable condition , it took the intervention of the staff from the HDU unit to assess me and put me on to 48hr agrressive iv drip monitoring to eventually stabalise my fluid loss and to reverse the AKI damage that was occurring to my kidneys.

I have to eat more often now to try and get the same energy as before.
The food is in and out of me in 12hrs or less at the mo and have a fairly strict low fibre diet to allow my digestive system to adjust.

Our NHS is very much alaigned by the same moaners who visit there GP's daily weekly , the same old moaners.
It isn't until one is hopsitalised and see the absolute wonderful caring work that all the staff do and have to carry out that one will realise we in the UK are very very lucky to have such a national treasure/institution at our disposal if we are unlucky to need it.

 

[Nealh]

Going back to the smaller lightweight hubs.
Most folks poo -poo them simply because they know little of how to use them or pair them up with a very good control system such as the variable current controllers like the KT.

I suspect nearly every person who poo- poos them has simply ridden a crappy 3spd basic speed controller bike or have been brainwashed by the mid drive rubbish spouted out time and again.
Most bike dealers have no idea about current control or the differing hub motor windings one can buy for a biles application/intended use.

I have ridden hub bikes with KT systems in practically all the offroad conditons one can expect to encounter from dry arid hot condition to bog mud conditions and those who know about them the wet chalky paste conditions the SouthDowns produces after heavy rain .
When I ride offrroad it isn't silly man made park trails that most go to , it is real world cycling , off the beaten tracks/farm tracks byways/ bridle paths and esp on the South and North Downs the well off beaten routes where one barely sees another soul.