Finally bought a smaller folder for conversion...

morphix

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Oct 24, 2010
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Hi all!

FINALLY after months and months of searching I've purchased another bike for doing my second conversion... I've been looking for something lighter and smaller to replace my 26" folder as I have a bad knee can't carry it up and down stairs any more.

Anyway I need a bit of advice as I'm wondering if I've made a terrible move with this purchase..or possibly a very good one!

The bike is a Mezzo D9 (2nd hand, 18 months old - not used much so very tidy and cost me £250).

The Mezzo has 16" wheels and I'm not sure about this. I know Jerry and others have done 16" conversions...but I can't find any posts about the Mezzo specifically or anyone who has successfully converted one here.

I'm also a bit nervous about going from 26" to 16"...I'm a speed freak heh. I had planned to get a 20" bike and was aiming to get a Dahon JetStream 2nd hand but they keep going for silly prices out of my budget.

However I've read several reviews on the Mezzo D9 and it looks quite a decent bike with good gearing and cadence similar to normal road bikes, despite the 16" wheels.. it's also said to compare favourably against Bromptons with a similar compact folded size and it weighs only 11.7kg so ideal for taking on trains..an added bonus.

So, down to business...conversion options:

1) Rear wheel conversion and possibly downgrading the gears, or removing the gears completely and and leaving it highly geared in single gear (don't plan to ride unpowered).

2) Front wheel conversion and replacing the 9-speed gears with a neater 3-speed or 5-speed hub gear.

I think a rear wheel conversion is my preferred option and makes more sense because I want the motor to look inconspicuous, and also the rear track on the Mezzo means it makes more sense to mount everything there above the motor.

This bike has an unusual folding mechanism similar to the Brompton where both wheels fold in rather than a hinged frame.

I'd like to fit big apple tyres to make up for lack of suspension..do they come in 16"? If not, does anyone have any suggestions or ideas? I'd want puncture resistant tyres.

I'd welcome any advice or words of caution on this one! Particularly any recommendations for the motor and powering. I have a 36v battery I'd like to use, but if necessary I'll buy a lower voltage one.

As to the bike itself.. I haven't taken delivery yet so haven't been able to ride it unpowered to try it out..I'm taking a gamble with it but I figured at this price I can easily sell it on if it's not suitable as they're like £700+ new!

I wasn't sure about the weird appearance (particularly the bizarre handlebar) but on reading about the clever folding mechanism and rigid frame I understand the design better and maybe it will grow on me ;-)

As I said, I don't plan to ride the bike unpowered...it's main use will be for taking packages to the sorting office (the generous sized rear rack and a Mezzo tall bag available will be a bonus there)...it also will get light recreational use.






 
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morphix

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morphix

Esteemed Pedelecer
Oct 24, 2010
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119
Worcestershire
www.cyclecharge.org.uk
I'm used to 21-23mph on my 26" folder.. I need at least 20mph, mission impossible with 16" wheels?. But that's good news smaller motors can take higher voltage..I guess I won't need to buy a new battery then and can use my existing 36V 10Ah to save some cash.
 
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Another possibility is the 350w brushed motor kit from GNGebike. I think the 450w brushless one would be too big and heavy, but the 350w one is much smaller and probably won't interfere with folding. I haven' tried one, so I don't know what they're like, but I can imagine not as robust as a hub motor and a bit noisier. On the plus side, it'scheap, easier to install, has excellent climbing power, and wil provide its maxmum power at whatever speed so that if you're already pedalling at 15mph, you get 350w added to that - the same at 20mph. No hub-motored or other ready-made bike can do that (apart from exotica). If you order one, pay the second level shipping price, which is only slightly more than the minimum and it'll arrive in less than a week.

I think Old_Dave ordered one, but I haven't head anything since.
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morphix

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Oct 24, 2010
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Thanks that's something to consider!
 

Old_Dave

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Sep 15, 2012
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Lol...

Forgot to post that it arrived ok (apart from a little drop of customs charges), fitting was a breeze (very minor tweeks only)

Not run it yet as I'm still waiting on a thumb throttle from greenbikekit and I have a smaller top box for the batteries on the way cos my tape measure lied about the gap between the seat and the rack... Ho hum


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Old_Dave

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Sep 15, 2012
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P.S not to sure about it fitting on such a small frame with 16" wheels though, I will have a measure tomorrow and let you know how far the motor drops below and behind the BB centre point


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Old_Dave

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morphix

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Oct 24, 2010
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Sorry for the delay, but here are the pictures of the important measurements from the BB centre..

The kit is mid mounted 350W
Thanks Dave, I think I'd like to go with a rear hub though. I want the bike to look as non-electric as possible. Jerry tells me a front hub is out of the question on this bike as the front wheel releases from the dropouts for folding. The rear wheel also swings around to fold, but I don't think it will cause any problem?
 
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Old_Dave

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Good thinking, but with such a small rear wheel even with a higher rpm hub the top speed will be limited.... which maybe a good thing :p
 

morphix

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Oct 24, 2010
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Good thinking, but with such a small rear wheel even with a higher rpm hub the top speed will be limited.... which maybe a good thing :p
How limited do you think it will be, assuming at 328 RPM? On the one hand it will be good maybe as it will encourage me not to be lazy and pedal more...but on the other, it's nice to have the option to go fast, particularly as I'm always in a rush to get to the sorting office :p
 

morphix

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Oct 24, 2010
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Sorry for the delay, but here are the pictures of the important measurements from the BB centre..

The kit is mid mounted 350W
Actually looking at the original link you posted here it doesn't look so bad on the final finished product, especially the one in black which would blend in with my bike which is also black.. would this mid drive approach be faster than a hub motor then? I imagine you would need to be very highly geared to avoid freewheeling? Also how much skill would be needed to fit one of these mid drive kits? Is it something I could do myself with regular tools or would I need specialist stuff? I did my own conversion before but it was a simple front hub wheel replacement.
 

Old_Dave

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Sep 15, 2012
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Faster yes cos the bikes gears are used, the crank and also the motor have freewheels built in, basic hand tools are all thats required apart from the bike tools for extracting the cranks and the BB, bit of electrical skill in connecting wires up, skill level requires a modicum of common sense mix them all together and bobs your uncle.
 

morphix

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Oct 24, 2010
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Faster yes cos the bikes gears are used, the crank and also the motor have freewheels built in, basic hand tools are all thats required apart from the bike tools for extracting the cranks and the BB, bit of electrical skill in connecting wires up, skill level requires a modicum of common sense mix them all together and bobs your uncle.
I reckon I can do it then, I used to be an electronic technician a long time ago and still dabble a bit, but I'm not so hot at mechanical/engineering side of things. :eek:
 

morphix

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My bike will be arriving tomorrow or Thursday (hopefully in one piece as Parcel Farce are carrying it..cringe!) so if I have time I will post some pics and will do a test ride video, all being well.

Having decided on rear hub I've been looking at motor options on GBK and BMS...

Does anyone have any experience or knowledge of GBK-100R (Q100) or GBK-85 (Q85) motors supplied by GBK and BMS? These weigh 1.9kg and 2.1kg and look more powerful than the smaller tongxin motors, they are rated at 250-350W with 328 RPM option for 16" rim. Should stand up to over-volting I think. The Q85 at 1.9kg might be a good middle of the road compromise between a full-size 3kg+ motor and a smaller tongxin perhaps, however I don't think the Q85 is available in a rear wheel version oddly. Can't see one listed on either BMS or GBK.

I'm also interested to know how they perform compared to Bafang/8-Fun and whether it's worth taking on an extra kg of motor weight as these motors generally weigh 3kg and over.

On this build I'm looking at keeping the weight as low as possible (I'm trying to beat Jerry's < 17kg Brompton build :p)...so ideally I want a motor < 2kg)...I'd like something small and discrete (black would be nice) but which is not too under-powered. I'd like to do 15mph on the flat without pedalling and around 20mph with light pedalling.. I'm only light at 9.2 stone, reasonably fit and my bike weighs 11kg (probably a kg less if I decide to remove the gears).

I would consider a 200W tongxin, or something small as a try-out if someone can recommend a supplier and if they're not too expensive..I guess I could always sell it on if it's not up to the job..
 
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jerrysimon

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Aug 27, 2009
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Cambridge, UK
(I'm trying to beat Jerry's < 17kg Brompton build :p)
Fighting talk :p

Brompton Ti with 1.6kg Goldant front hub motor, 13.5kg "bike carry weight" and about 2kg bag weight including battery and controller in the other hand



I fear you may be searching for the Holy Grail in that you want light and quite a bit of power. I think Tongxin use to do Nano rear motors though it seems no longer do. You would need to email them.

Gearless_Motor-OutRider Eshop - EBike Kit Supplier-Complete Electric Bike Conversion System

You might want to check the rear fork spacing too.

Regards

Jerry
 
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