Conversion kit for my Crescent

Hello everyone, firstly i would like to introduce myself. My name is Mika im 28 from Finland,

 

I am new to electric bikes and looking to convert my bike to either a rear hub motor or a front hub motor. In Finland we have 1000W and 45 km/h(28mp/h) limits for ebikes so I'm looking 500W-1000W motor kit to achieve something like 40km/h (25 mp/h). Going to ride only on paved roads and my my budget is between 500-600€. Any recommendations on good kits, batteries and should I go for front or rear hub?

For front vs rear hub, there's plenty of comment on the forum but start with this recent posting here.

 

The general view seems to be a rear hub is preferred unless you have a specific reason for a front hub and certainly with motors of the power you are looking at, the rear hub motor definitely gets more votes!

There are a lot of different Crescent bikes and nearly all of them are unsuitable for a 500w or 1000w front motor. Maybe you could start by showing us what you have instead of leaving us to guess. Also, we need to know if it has free-wheel or free-hub gears, and how many.

For front vs rear hub, there's plenty of comment on the forum but start with this recent posting here.

 

The general view seems to be a rear hub is preferred unless you have a specific reason for a front hub and certainly with motors of the power you are looking at, the rear hub motor definitely gets more votes!

Yes it seems like rear hub is the better option here.

 

Here are some pictures of my bike also.

OK, so you need something like a rear 500w geared cassette motor running at 48v to get what you want. You'll probably have to buy you stuff from China, either direct from the re-sellers or via Aliexpress. Your budget looks a bit tight.

 

You could get one of those cheap direct drive motor 1000w kits, which are very heavy, but you will have to pay around 400 Euros just for the battery and you'll have to throw away all your nice gears/shifters, etc, and replace them with a cheap 5-speed or 7-speed set. IMHO, if you want to use a motor like that, you'd be better off using a cheap steel-framed bike to convert.

 

That brings me to the next point. There's no way your brakes are going to cope with the additional mass and speed after fitting a kit capable of doing what you want. For that, you need hydraulic disc brakes, so you need to find a new donor bike with disc brakes.

 

Sorry for the bad news. Your Crescent bike is just about OK for converting with a 25km/h kit, but to be honest, I wouldn't even do that with those brakes.

OK, so you need something like a rear 500w geared cassette motor running at 48v to get what you want. You'll probably have to buy you stuff from China, either direct from the re-sellers or via Aliexpress. Your budget looks a bit tight.

 

You could get one of those cheap direct drive motor 1000w kits, which are very heavy, but you will have to pay around 400 Euros just for the battery and you'll have to throw away all your nice gears/shifters, etc, and replace them with a cheap 5-speed or 7-speed set. IMHO, if you want to use a motor like that, you'd be better off using a cheap steel-framed bike to convert.

 

That brings me to the next point. There's no way your brakes are going to cope with the additional mass and speed after fitting a kit capable of doing what you want. For that, you need hydraulic disc brakes, so you need to find a new donor bike with disc brakes.

 

Sorry for the bad news. Your Crescent bike is just about OK for converting with a 25km/h kit, but to be honest, I wouldn't even do that with those brakes.

Thanks for input I'll screen for new bike and sell this one. Also I red about kool stop branded v-pads which are supposed to be really good and on par with disc brakes. Aliexpress/Ebay is fine for me to order ebike kit. That 48V 500W geared motor sounds good to me.

 

Something like this? https://www.aliexpress.com/item/32961457003.html

 

 

I'll might buy Tunturi rx500 hybrid bike for my project after I manage to sell my old bike. 360 view here: https://www.tunturi.fi/tuote/arkisto/2019/hybridipyorat-2019/rx-500-2018-19/

Edited August 12, 20205 yr by mt247

Thanks for input I'll screen for new bike and sell this one. Also I red about kool stop branded v-pads which are supposed to be really good and on par with disc brakes. Aliexpress/Ebay is fine for me to order ebike kit. That 48V 500W geared motor sounds good to me.

 

Something like this? https://www.aliexpress.com/item/32961457003.html

 

 

I'll might buy Tunturi rx500 hybrid bike for my project after I manage to sell my old bike. 360 view here: https://www.tunturi.fi/tuote/arkisto/2019/hybridipyorat-2019/rx-500-2018-19/

[ATTACH alt=tunturi rx500.jpg]37720[/ATTACH]

Get yourself a back-pack and put about 8kg of potatoes in it, then go and find a steep hill that will get you up to 40 km/h. see how well your brakes work. Kool-stop pads will make about 10% difference for the first 2 seconds, then they'll melt just the same as your present ones.

Get yourself a back-pack and put about 8kg of potatoes in it, then go and find a steep hill that will get you up to 40 km/h. see how well your brakes work. Kool-stop pads will make about 10% difference for the first 2 seconds, then they'll melt just the same as your present ones.

Most likely so, I'm looking for new bike. Do you have any recommendations for geared 500-750W 48V motors?

That's an interesting point of view about the brakes, the 8kg of potatoes, 40km/hr etc. and the donar bike which is using 'V' brakes

 

In determining if those brakes might be sufficient, I'd like to offer my own experiences and that is,

> I have done a fair few thousands miles cycle camping, average kit weight 12Kg (plus me at 90Kg - on a good day ) on a Dawes Galaxy (non electric) with canti-lever brakes (which are on a par with the V brake if set up correctly).

> My trips have included many hilly areas including some of the higher Cols and passes in the French and Swiss alps where descents have in some cases have been loooong and steep and I have never had issues with stopping, brake blocks failing or rims over heating (although I have had to cool the rims in a stream once after a long descent in Portugal, but no brake failures though).

 

So yes, I think the loaded rucksack on a steep descent is a very good idea for you to see how your brakes perform and to enable you to make a judgement on efficacy and is maybe something you should try before discounting the 'V' brake arangement.

 

Finally, that's a nice looking donor bike - if you wanted to use it but were not confident in the stopping power of the 'V' brake, you could always consider changing to something like Magura hydraulic rim brakes - we have the Magura HS31 on our tandem which with camping kit and two persons comes in at well over 200kg and stops fine.

Finally, that's a nice looking donor bike - if you wanted to use it but were not confident in the stopping power of the 'V' brake, you could always consider changing to something like Magura hydraulic rim brakes - we have the Magura HS31 on our tandem which with camping kit and two persons comes in at well over 200kg and stops fine.

A new donor bike would be cheaper than two sets of hydraulic rim brakes, and disc brakes are better anyway.

I've found V brakes very effective; work well on our tandem. I can see that they would not be suitable for a long decent because of heat. I much prefer them to cantilever ones; for me they work more effectively and

are easier to adjust.

 

I do not like the Magura hydraulic rim brakes on the Motus. An absolute pain to adjust and they don't have such a firm stopping action as V brakes. (Maybe they need bleeding?)

 

I've never had disk brakes (hydraulic or cable) so can't compare. From what everybody says they are superior.

Aeikema sell a 500w 48v cassette model or a 800w freewheel model both the same size.

The 800w is only a slower wound hub though.

Which rpm model you buy not only depends on the speed you want but also terrain, do you have any hills to climb ?

http://www.topbikekit.com/akm128cst-48v500w-rear-driving-hub-motor-cassette-motor-for-ebike-p-723.html

 

http://www.topbikekit.com/akm128h-36v48v-800w-rear-driving-hub-motor-for-ebike-p-889.html

Edited August 12, 20205 yr by Nealh

An average rider on a bike like OP's might average around 12 mph. His brakes are probably adequate for that.

 

When he puts a kit on that bike and starts averaging 25 mph, he will have approximately 5 times as much kinetic energy, which will require 5 times as much braking to dissipate it. Imagine that bike with 5 sets of caliper brakes on each wheel. That would give him the same braking efficiency as he already has. Some of you guys have got no idea about basic physics.

KE=1/2mV x V

I've found V brakes very effective; work well on our tandem. I can see that they would not be suitable for a long decent because of heat. I much prefer them to cantilever ones; for me they work more effectively and

are easier to adjust.

Irrespective of V or Canti or Magura rim brakes, a 3rd brake on a tandem is desirable for long descents to 'share' the load amongst all braking surfaces. On our tandem the 3rd brake is a rear disc - that combination has worked well for us.

 

I do not like the Magura hydraulic rim brakes on the Motus. An absolute pain to adjust and they don't have such a firm stopping action as V brakes. (Maybe they need bleeding?)

I think you've been unlucky with your Maguras - I've had ours on the Tandem for 8 years and many thousands of miles and have only had to change the brake blocks - no adjustments or bleeding in that time.

 

I've never had disk brakes (hydraulic or cable) so can't compare. From what everybody says they are superior.

 

That's why forums are so good - a great platform for debate. I have had disc brakes (cable and hydraulic) and yes they are good and easier on the fingers if descending a lot (as in hours at a time over several days), but irrespective of the make or model I've had, disc rub during free wheeling is something that has plagued me (probably an adjustment thing).

 

You do hear of discs overheating and possibly warping on long descents but I've no experience of using them like that so I can't really comment as to whether that is a real risk for most cyclist.

Aeikema sell a 500w 48v cassette model or a 800w freewheel model both the same size.

The 800w is only a slower wound hub though.

Which rpm model you buy not only depends on the speed you want but also terrain, do you have any hills to climb ?

http://www.topbikekit.com/akm128cst-48v500w-rear-driving-hub-motor-cassette-motor-for-ebike-p-723.html

 

http://www.topbikekit.com/akm128h-36v48v-800w-rear-driving-hub-motor-for-ebike-p-889.html

This looks good here is my commute route:

 

Is there version with spokes+rim already attached to motor? I think it's too difficult task to do myself.

This looks good here is my commute route:

[ATTACH alt=commute route2.jpg]37757[/ATTACH]

 

Is there version with spokes+rim already attached to motor? I think it's too difficult task to do myself.

https://bmsbattery.com/ebike/769-16768-q128c-135mm-500w-rear-driving-ebike-hub-motor-wheel-ebike-kit.html#/43-voltage-48v/214-rpm-328

Is there version with spokes+rim already attached to motor? I think it's too difficult task to do myself.

Postage from China is a bit pricey for complete wheels as you will see. Ask around your local bike shops, assuming you have some, for a decent wheel builder. Should work out cheaper.

The price of a hand built wheel then? For guidance

> Spa Cycles charge £99 for a 36 hole wheel on 26" or 700c rim with a standard Deore hub - I don't know if they build wheels onto hub motors though

> If you were buying the rim (around £25 plus p&p) and spokes (£20) plus then someone's time to build the wheel, you can see that £70 might be a keen price

 

Both of these options likely give you a better quality rim and build than the factory built wheel from China, but it comes at a price.

 

So either factor that against the extra postage costs from China vs buying the motor already laced into a rim from a UK supplier.

 

Alternatively, learn to build your own wheels - not straight forward of course but it is not the dark art you might think it is either.

Edited August 13, 20205 yr by Bikes4two

Most bike shops won't touch it because a hub-motor doesn't fit their fixture. The cost is about equal between buying it built and getting a shop to build it. In fact the shop will probably be dearer because the costs are close when you build it yourself.

Postage from China is a bit pricey for complete wheels as you will see. Ask around your local bike shops, assuming you have some, for a decent wheel builder. Should work out cheaper.

So either factor that against the extra postage costs from China vs buying the motor already laced into a rim from a UK supplier.

 

Alternatively, learn to build your own wheels - not straight forward of course but it is not the dark art you might think it is either.

 

How about these aliexpress kits? You can get whole kit under 250€ with free postage, no taxes and EU warehouse:

 

https://www.aliexpress.com/item/32827269926.html

 

Complete kit with battery and mid motor: 565€:

https://www.aliexpress.com/item/32827447339.html

Edited August 14, 20205 yr by mt247

That kit looks OK. You need the 15C cassette version. If you want to order, show us what options you are planning before ordering. It's 145mm wide, so you will have to stretch you frame a bit to fit it in, and you may have to dish the wheel too to get the rim central in the frame. That's normal with cassette motors.

 

One important thing. It doesn't tell you the motor speed. All electric motors have a maximum speed, which is fixed, no matterhow much power you five them. A motor makes its maximum power and efficiency at about 75% to 80% of its maximum speed. If you want to ride at 40km/h, you ned a motor has a maximum speed of 50km/h, which is approximately 400 rpm. Most sellers don't have a clue about these things. You should never buy a motor without knowing its max rpm unless you would be happy with 25km/h. You should ask the supplier about the speed to see if you get a sensible answer from them.

That kit looks OK. You need the 15C cassette version. If you want to order, show us what options you are planning before ordering.

 

One important thing. It doesn't tell you the motor speed. All electric motors have a maximum speed, which is fixed, no matterhow much power you five them. A motor makes its maximum power and efficiency at about 75% to 80% of its maximum speed. If you want to ride at 40km/h, you ned a motor has a maximum speed of 50km/h, which is approximately 400 rpm. Most sellers don't have a clue about these things. You should never buy a motor without knowing its max rpm unless you would be happy with 25km/h. You should ask the supplier about the speed to see if you get a sensible answer from them.

Will do, mid motors looks also interesting and they aren't even that much more expensive compared to hub motors it seems. 560€ for complete motor kit+ 13Ah 48V battery doesn't seem that bad deal.

Will do, mid motors looks also interesting and they aren't even that much more expensive compared to hub motors it seems. 560€ for complete motor kit+ 13Ah 48V battery doesn't seem that bad deal.

It's easier to get any speed with a mid motor because you only have to choose one with enough power and the right gearing. I personally don't like mid motors for riding on the road. You have to be in the right gear all the time, which can become tedious, especially in winter when you have cold hands. Also, you will have 5 times the power going through the drive train compared with a non-electric bike, which can do a lot of damage and wear to the components.

It's easier to get any speed with a mid motor because you only have to choose one with enough power and the right gearing. I personally don't like mid motors for riding on the road. You have to be in the right gear all the time, which can become tedious, especially in winter when you have cold hands. Also, you will have 5 times the power going through the drive train compared with a non-electric bike, which can do a lot of damage and wear to the components.

With those points the hub motor sounds better for my usage after all.

With those points the hub motor sounds better for my usage after all.

Everything has advantages and disadvantages.