Kit for a Trek Mountain Bike

[TomBrown]

Hi, my name is Tom and I am a new member to the forum but have been a regular visitor for the past 2 years.

I currently have a number of bikes: Nano Brompton M3L, Brompton M6L, Trek 4300 16” frame, 24 speed with combination shifters/V-brakes and a Trek 4500 16” frame, 27 speed with Hydraulic disc brakes that I can share with my family or choose for a particular ride.

I have been thinking of converting one of the two mountain bikes to electric for a while now and have been doing a bit of research on possible road legal kits.

The nano brompton motor failed last week, it had gone through a period of ratcheting and then back to normal but now the motor just spins in the hub with no drive to the wheel, so I have sent the wheel of to Tony Castles (EWC) for repair. Anyway that has spurred me on to get one of the mountain bikes converted. I am hoping to do the conversion with minimal changes to the donor bike so I can convert it back when required, but realise there is no easy marriage between bike and available kits and some compromise may have to be made. So I am hoping you will be able to help me with possible solutions.

So far I have narrowed the kit down to:

1. A front wheel Bafang 8fun motor, easy to convert back to original. Most forum members seem happy with the motor performance.

2. Rack mounted 36v 9/10Ah battery, can remove battery to convert back to original. Not adverse to a bottle battery, but not sure it will fit in a 16” frame the 4500 has a particularly small triangle and also the weight of 3kg battery on the fixings. Don’t like a seat post mounted solution, as different people will use the bike.

3. Possible UK kits are, Alien Bike road legal kit or 8Funbike rack mount kit, there does not seem to be a lot of technical difference between these kits unless I have missed something. Warranty is 1 year on Alien kit and 1 year on motor and battery and 6 months on other parts on 8funbike kit from the email they sent me. Both say they will supply parts out of warranty and responded quickly to questions. So I think it will come down to price, quality and support. You thoughts would be appreciated.

My first choice would be to use the Trek 4300 as the donor bike but I am keeping my options open.

Issues to resolve and questions:

1.Will the motor fit in the forks:
a. Trek 4300: Fork dropout 10mm, Fork width 101mm, fork narrowest point 90mm. So looks ok, but fork narrows on both sides about 15.5mm from centre of axle. The motor cable side washers (1 + torque washer) are 5.5mm in width from schematic so the motor will clear fork by at least 0.5mm. On the disc side its no so clear, the nearest part of the motor has a diameter of 33mm (radius = 16.5mm) giving a vertical clash of 1mm. I am hoping the washers will push the motor out from the fork enough so they miss. The schematic does not show this distance. Does anyone know the distance between the fork and the side of the motor? I think it is the width of the torque washer (3.5mm) and the 1st washer (2mm) is recessed into the motor. I think 3.5mm will be just enough for the motor to miss the fork them by a hairs width. Confirmation would put my mind at rest.

b. Trek 4500: Fork dropout 10mm, Fork width 101mm, fork narrowest point 94mm. So looks ok. The issue here is the motor/spokes clashing with the disc calliper (162mm diameter disc). Does anyone know if these kits use the SWXK or the later more disc friendly profiled SWXK-5. I asked 8Funbike and they think their kit uses the SWXK-5 but were not 100% sure.

2. Brake switches.
Trek 4300 combined shifters and brake lever, Trek 4500 Hydraulic. Changing the brake levers on the Trek 4500 is not an option. Has anyone successfully implemented a reed switch sensor solution like the Daahub kit? Are the brake switches normally closed and open when you brake or the other way around? The only other solution I have seen is the one on the Oxydrive kit where the sensor fits on the brake cable, it looks like a 3 wire hall sensor so would not be compatible with the two wire switched controller or work with hydraulic brakes.

3. What is the current rating of the controllers? I think the Alien Kit is 15A.

Regards

Tom

 

[Cyclezee]

Hi Tom,

Welcome to the forum.

An eZee kit would meet your criteria and fit your front forks, the dimensions can be seen via the following link courtesy of e.bikes.ca http://www.ebikes.ca/store/diagrams/MeZeeF.pdf

A 180 mm disc rotor is supplied with the kit as standard and an adapter would allow you to fit this, but we can also supply a 160 mm rotor if preferred..

Brake levers with cut outs are supplied, but they do not have to be fitted.

An eZee controller is rated at 20A.

Some examples of eZee bikes and conversions can be seen here http://www.cyclezee.com/gallery.html

Regards,

 

[TomBrown]

Thanks,

I will check it out.

Regards

Tom

 

[JuicyBike]

Hi Tom
This post may be of interest to you...

Regarding your question 2 above. The third wire from the brake cut-off needs a 5volt supply, generally taken from the 5V supply to the throttle. We use a similar type of switch for our hydraulic brake conversion kits.

Hope this helps.

Addm: Just seen your criteria 2, rack mount, which we are out of at the mo.

 

[TomBrown]

Hi Bob,

Thanks for the info. I didn't know you did a rack mount kit, i looked on your web site and only found the seat post mounted battery kit (which will not work for me) and no details on the motor. How does your hydraulic brake switch conversion work.

Regards

Tom

 

[Cyclezee]

Thanks,

I will check it out.

Regards

Tom

Hi again Tom,

I don't know where you live, but if you are able to get to Milton Keynes, we have demonstrator that you are welcome to test ride.

Please click on image to enlarge.


eZee kits are the most versatile available in the UK.

 

[TomBrown]

Hi,

I live in Wigan so not so easy to pop down to Milton Keynes.

I have had a look at the eZee motor schematic and it has a slimmer profile than the Bafang 8Fun SWXK/SWXK-5, the eZee is about 85mm and the 8Fun about 91mm, so the eZee should be an easier fit. However like the 8Fun the eZee schematic does not show the actual width of the motor and thickness of the washers on each side. So i am sorry but i have a few questions to ask its my engineering background delving into the detail.

1. What is the width of the washers on each side of the motor to make up the 100mm fork width? It looks to be about 7.5mm each side.
2. Is the profile on each side of the motor about 40mm in diameter?
3. The axle looks to be 12mm in diameter, is it milled with flats to fit 10mm dropouts?
4. What type of brake interface does the controller support, a. 3 wire hall sensor (+5v, Gnd, Signal), b. 2 wire switch or c. Other type. I need to find a solution to the combined brake/shifter and hydraulic bake issue.
5. What parts are included in the eZee kit?
6. Do you know of any good background informaton on controllers?

See below pictures of Trek 4300 fork

Regards

Tom

 

[banbury frank]

Hi I would fit a ezee rear wheel kit with twist and go throttle no problem with brake levers and silly pedal sensors we never fit then will supply the dropout adapters the rear off the bike is a lot stronger

the best is a standard setup with hall sensors

Their kit are not the cheapest but you get what you pay for with Quality and good support

Make sure you buy the right AH battery ezee do a choice 10ah or 14 ah


Frank

 

[Cyclezee]

Hi,

I live in Wigan so not so easy to pop down to Milton Keynes.

I have had a look at the eZee motor schematic and it has a slimmer profile than the Bafang 8Fun SWXK/SWXK-5, the eZee is about 85mm and the 8Fun about 91mm, so the eZee should be an easier fit. However like the 8Fun the eZee schematic does not show the actual width of the motor and thickness of the washers on each side. So i am sorry but i have a few questions to ask its my engineering background delving into the detail.

1. What is the width of the washers on each of the motor to make up the 100mm fork width? It looks to be about 7.5mm each side.
2. Is the profile on each side of the motor about 40mm in diameter?
3. The axle looks to be 12mm in diameter, is it milled with flats to fit 10mm dropouts?
4. What type of brake interface does the controller support, a. 3 wire hall sensor (+5v, Gnd, Signal), b. 2 wire switch or c. Other type. I need to find a solution to the combined brake/shifter and hydraulic bake issue.
5. What parts are included in the eZee kit?
6. Do you know of any good background informaton on controllers?

See below pictures of Trek 4300 fork

Regards

Tom

View attachment 3562View attachment 3563

Hi Tom,

It looks Frank has already some questions for me, thanks Frank

I will now try and fill in the blanks regarding a front wheel kit. Please note that we also have rear wheel kits if your prefer.

1. There are no washers between the motor and the dropouts, the flats on the axle are 100 mm apart.
2. I'm not sure what you mean by the profile Tom?
3. The axle is indeed 12 mm diameter and the flats are milled to fit 10 mm dropouts.
4. The brake interface is a 2 wire switch. From my experience, most people do not fit the supplied brake levers and therefore do not use cutouts.
5. The photo below shows and lists the kit components with the exception of the charger which is supplied but shown separately, this comes with UK 13 amp plug fitted.
6. The 20 amp eZee controller with a 4110 Mosfet is suitable for batteries upto and including 48v, it is waterproof, potted and sealed in an aluminium casing. It has a self diagnostic error troubleshooting LED light coding system.

Please click on images to enlarge​

I hope that this helpful Tom, please let me know if you require further information.

Regards,

 

[TomBrown]

Hi,

Thanks for your answers.

I prefer the front wheel motor as it is easier to to swap back to the original wheel. I think general opinion is that front alloy forks can withstand the torque of a 250w motor. Can also add a torque bar for extra support.

With regard to question 2. I was trying to understand how the motor steps up in diameter within the first 12mm from the fork on each side. As you can see from the pictures of the fork it narrows by 4 to 5mm on each side about 15.5mm up from the centre of the axle. This is the critical area in dertermining if the motor will fit.

With regard to the brake:

a. I would like the bike to be road legal especially as i will not be the only one using it.
b. I have notice when using my nano brompton that there is a tendancy to not release the twist throttle completely when braking and was concerned that this woud put a strain on the motor if no cutoff was applied.

Regards

Tom

 

[Cyclezee]

Hi Tom,

I understand your preference for the front wheel kit, please note that a versatile torque plate set as discussed in this thread http://www.pedelecs.co.uk/forum/electric-bicycles/10926-bargain-year-torque-arms.html is included with the kit.

From the measurements that you provide I am fairly certain that the motor will fit the your forks.

I appreciate your desire for legality when it comes to brake cutouts, this issue would require a work around.

Regarding throttle release, I can only speak from my own experience as no one has reported it being an issue before, I apply the brakes and release the throttle simultaneously.

Regards,

 

[PhilYerBoots]

Hi Tom.

I converted my Giant 'comfort' style bike with an Ezee front wheel kit back in January and have been very happy with the result. I'm just fitting some upgrades including better 'v' brakes and separate shifters to replace the standard combo ones to enable fitting of the ezee cut-off brake levers, which I've since decided are worth fitting for saftey reasons.
PM me if you want a demo as I'm a bit closer than, in Wallasey on the Wirral, which is not that far from you in Wigan.

Good luck with your conversion.
Phil.

 

[PJM]

Would it be possible to cut off the brake levers and connect the two wires from the brake cuts outs to a small magnetic reed switch from maplins or RS switches? A bit of tape to get it in the right place and the epoxy it once happy. Could you also tell me what the overall all up weight of the kit and rack is for the 10AH battery.

 

[Cyclezee]

Hi PJM,

Yes it would be possible to remove the brake cutout cable from the brake levers and adapt as you suggest thereby allowing the brake cutout facility to be operated without changing the existing brake levers.

The weight of a complete eZee kit as shown below excluding wheel and M+ tyre as supplied but including a rear City type battery rack/carrier is 9 Kg.

 

[PJM]

Is that heavy?

Hi PJM,

Yes it would be possible to remove the brake cutout cable from the brake levers and adapt as you suggest thereby allowing the brake cutout facility to be operated without changing the existing brake levers.

The weight of a complete eZee kit as shown below excluding wheel and M+ tyre as supplied but including a rear City type battery rack/carrier is 9 Kg.

View attachment 3585View attachment 3586

Hi, is that heavy? or are the quoted weights of Oxydrive and similar kits at circa 7kg being optimistic ...

 

[TomBrown]

Hi Phil,

Thanks for the offer of a demo. I quite often comeover and stop at Thurstaston (Wirral Country Park Caravan club site) in the motorhome or use the train as i live on the northern line. Did the Wirral coastal path New Brighton to Parkgate and back last year on my non-electric brompton, my legs were sore the day after.

I like the eZee kit, but i am still trying to decide between it and the 8fun kit. I want to upgrade my Trek 4300 (combined brakes v-brake/shifters) first for my son to use to comute to work, he is currently working nights, finishes before any transport starts and it is mainly up hill all the way home. Then i aim to upgrade my trek 4500 (hydraulic disk brakes), so i have to concider which solution will be best against the overall budget, i may end up with one of each kit which would be an interesting comparison.

The brake switching issue seems to be very common, given that most mountain bikes use combined brakes/shifters and hydraulic disc brakes are becoming more common you would have thought the kit manufactures would have come up with an off the shelf solution. As PJM has just posted it must be possible to come up with a reliable reed switch solution that solves both types of brake situation, so i will be investigating this further.

I don't know if you have an ezee rack mount battery but i was wondering how robust and water proof they are as i am sure i read somewere that they have a plastic casing, i forgot to ask.

Regards

Tom

 

[Cyclezee]

Hi, is that heavy? or are the quoted weights of Oxydrive and similar kits at circa 7kg being optimistic ...

Hi PJM,

I would never claim the eZee kit is the lightest, the eZee motor is almost certainly heavier than those that you mention, but it is also more powerful and the battery has a higher capacity.

The weight is very similar to an equivalent BionX system.

The rear rack weighs over a kilo, but can carry 25Kg.

 

[Cyclezee]

I don't know if you have an ezee rack mount battery but i was wondering how robust and water proof they are as i am sure i read somewere that they have a plastic casing, i forgot to ask.

Regards

Tom

To preempt a reply from Phil, the eZee batteries have a tough, rigid and waterproof plastic case and are supplied with soft battery bag with straps so that it can be strapped to a standard rear carrier if desired.

 

[PhilYerBoots]

You're welcome Tom and the offer stands whenever you're ready.

I'm not surprised your legs were sore after that ride..! I hope you made it worth the journey by sampling either Parkgates' fish & chips or its famous ice cream shop, or preferably both..!
The furthest we've done so far is New Brighton to Thurstaston and back with me on my un-powered mtb and my wife leading the way on her Juicy Classic. Now we're both electric and once the weather improves we'll be trying the Parkgate run.

I was initially favouring either the 8Fun or BPM kit but was swayed by the good reports I read about the Ezee motors and recommendations on here. Its not the cheapest but the power, quality and support are excellent. Don't forget the Ezee kits can be de-restricted to give 20mph+ for a bit of 'off-road' fun As you say it will be interesting to compare kits if you end up with 2 different conversions.

Like your Trek 4300 my Giant had combi brake/shifters so I've recently changed these for separate 3+7 shifters and fitted the Ezee brake levers. I didn't bother with the pedal sensor as you still need to use the throttle while you're pedalling anyway.

I agree that kits should offer an easier cut-out option for using hydraulics, as I miss the stopping power of my Scott's hydraulic brakes compared to the Giant (although upgrading to Deore LX 'v' brakes has gone some way to bridging that gap..)

I've used my own rack with the battery bag's velcro straps and a couple of bungees to make sure. Its a pretty stealthy solution judging by comments I've had and definitely waterproof as he says. The Ezee rack looks a neater solution and the battery locks to the rack for security but imo at £60 its expensive for what it is.

Anyway good luck with your project..!

Cheers,
Phil.