Commute Road Bike Build front/rear hub or mid-drive?

[jollyDodger]

I've been riding a Sparta r10i for the last two weeks dong 18miles a day including living at the top of crystal palace hill and its been amazing. The list of features is outstanding, it's super robust, extremely comfortable and a wonderful piece of engineering. But... it's not what i'm used too. The Sparta has an upright riding position, (I usually ride a drop-bar road bike), I can't do more than 20mph on the flat without power (my old normal bike is lightweight with 24mph as my top speed). Also I have maintained and rebuilt my own bikes for the last 20 years and with the Sparta it's not really designed to be tinkered with, and is more of dealer maintenance thing. But.... i have fallen in love with electric bikes.. so now i want to build one that is like my road bike but, fast at the lights, can go up steep hills and if i'm feeling lazy, can power me home.

I have a couple of old road bikes in the garage (a r400 80's alu. cannondale, and a 90's hybrid alu. Claud Butler). Both are fairly trashed and need full chainset replacements, but would work as lightweight bases.

I require:
- lightweight so i'm not super slow unassisted
- 20 miles range being lazy, 50 miles working the bike.
- 20mph with power (but 15.5mph on public roads of course)
- Gears (I found i get 30% more battery if i use gears at lights) - would like a alfine, would love a belt drive.
- Quick off at the lights (using pedal assist, rather than a throttle, as i need hands free to work the gears)
- Stealth, don't steal me from a urban street (but i still have insurance) - 1) battery & display has to be removable (or have no display as i don't see the need for it apart to check battery and select power level). 2) Battery needs to be a bottle or on the rear rack type, dolphin batteries are too obvious. 3) the controller needs to be integrated/hidden. 4) is quiet-ish.
- Not all weight is at the rear (I like batteries on the rear rack, but when combined with a rear hub, rear wheel skids are far too easy when suddenly braking.

Confusion:
- Is a front hub bad? Friends have said that a front hub is the worst of the three ront/rear hub or mid-drive choices, due to lack of traction, particularly on hills?
- Are there any hub drives that make it ok to change a flat tire by the side of the road, have people found that rims with hub drives buckle or require more tru'ing?
- Are hub drives more efficient?
- Are there any other recommended mid-drivs apart from the 8fun. These look interesting? Pendix or Bikee Bike or Binova Flow

Any advice please?

 

[anotherkiwi]

My vote would be mid-drive (Bafang, GSM,...) and Alfine.
If you want a belt drive you need a special frame
Bottle battery with controller in the base

1. Alfine has the gear shifter you need for drop bars, and any mid drive is good for 33 km/h you can play with chainring size and sprocket size to get the gear ratio you need

2. The chainstay or seat stay need to be cut to get a belt in. Chains and chainline are less of a problem with single cog/sprocket and you can enclose much of the chain to protect jeans.

3. I don't know of any bottle battery controller for over 15 Amps but you probably don't need more than 15 Amps. I think the HL battery is pretty discreet others disagree. It has the advantage of hosting an 18 Amp controller

You don't need to mount the LCD on the handlebars but you need to hide it away somewhere. You would lengthen the wire from the off/on assistance selector button and put just that on the handle bar.

Alfine has the about the same tube changing issues as a hub motor. Get some Schwalbe puncture resistant tyres. The new Durano-e looks like a good performance road bike tyre with some puncture protection.

The other type of motor you cite is too recent for us to know what they are worth on the road.

Last of all if you are a cyclist you won't like the weight of a hub in the front wheel.

 

[DavidSWP]

Hi,

The bike I've added my mid-drive motor to was originally a belt drive (Trek Soho Deluxe) with a rear 8 speed Nexus gear hub and Nexave roller brake. Alfine hubs are usually combined with rear disc brakes so your bikes would ideally have mountings for a rear disc brake, although I think you could just run rim brakes - just I've never seen an Alfine hub bike without an attached disc brake.

There may be several options for belt drives, but the only one that I am aware of is the Gates Carbon Drive which my Trek had. What I would say is that its very difficult to source the parts for these in the UK. My belt was on the last adjustment and I wanted to upgrade it to the later 'Center Track' version which would have required a new front ring and rear sprocket and a new belt. The costs of importing these from the US put me off a bit so I ended up just putting a chain on it. Cheap, easy and works. If wanted the mid-drive then you're almost certainly going to need a converter to attach the belt drive ring to the motor. I am not sure which BCD sizes the converters for the common mid-drive motors allow, but I've only ever seen 130 BCD Gates belt drive chain rings.

Also Belt Drives put quite a bit of extra strain on the bottom bracket - not sure how this would affect the common mid-drive motors (if at all).

I wouldn't say that front hubs are bad. I had one on a bike a number of years ago. They are better if you are ever going to go off-road, dirt tracks or through mud, snow or whatever in much the same way as a front wheel drive car is better in these conditions because you can point the wheel in the direction you want the power to go.

Changing a tire or inner tube with a hub drive just means you would have to carry a spanner with you because you can't use quick release. You have the same issue with an Alfine or Nexus hub gear.

Hub drives are less efficient (and less capable) for climbing reasonably steep hills where your speed is low, but for cruising they are similar. Each motor of course can have different efficiency rating.

 

[DavidSWP]

My vote would be mid-drive (Bafang, GSM,...) and Alfine.
If you want a belt drive you need a special frame

2. The chainstay or seat stay need to be cut to get a belt in. .

Yes, I forgot about this, my Trek has a special removable section on the chainstay so that the belt can be fitted.

Also to use an Alfine or other hub gear your bike would really need to have track (horizontal) drop-outs. If yours don't have this then you could try and use a chain tensioner. My old bike with Nexus gear hub had vertical drop-outs and I used a Surly Singulator tensioner which was okish but not perfect.

Without horizontal drop-outs a belt drive would be out of the question. Although it probably already is because of the chainstay issue. If you wanted to go this route then you'd be best picking up a bike designed for belt drive. You can pick up a Trek Soho Deluxe for about £250 on ebay but they are not that lightweight (14kg).

 

[trex]

You said you want fast and light: Lightweight bikes tend to have fast rolling tyres and derailleur, that limits your choices to either crank drive or lightweight rear hub drive.
You said you are on the wrong side of 100kg, my recommendation: BBS01 CD kit or BBS02 if you weigh more than 120kgs.

 

[jollyDodger]

Good info!

- Good to know that its easy to fix a flat on a rear hub, as long as i have a pocket alu. cycle spanner & I will check for horizontal drop-outs

So a belt drive is a no-no for me as it would require a new frame (but defo. something to look out for: http://en.r-m.de/bike/roadster-touring/ & http://www.bikesoup.com/magazine/buyers-guide-10-best-gates-carbon-belt-drive-bikes/).

So.. two votes for a mid drive with a rear gear hub, but none for a rear hub.

Is the future for rear hubs over?'he says with troll hat'? I thought hubs had less moving parts, lighter, less friction and so more reliable and efficient?

so...I still have to decide between a rear hub with derailer OR mid-drive with hub gears for this road bike build. I like the rear-hub for the above reasons, but like the midDrive for simplifying the rear wheel, making it stronger and centring the weight (so i have the option of putting the battery on the rear rack)

 

[trex]

I think the future for direct drive is truly over if you want to make an legal EAPC. I don't know exactly your weight, so can't recommend a suitable geared hub motor.

 

[jollyDodger]

I think the future for direct drive is truly over if you want to make an legal EAPC. I don't know exactly your weight, so can't recommend a suitable geared hub motor.

Don't you know its rude to ask a middle aged man his exact weight. ;-) I'm about 11 stone.

But how to chosse between rear hub or midDrive you recommend (apart from the current legal issues)?

O.T. Yep... i guess the current laws are inadequate and a new class of vehicle will eventual be created to keep up with tech developments. I vote 20mph road legal not 15mph. I expect there are many threads on this here already. /O.T.

 

[trex]

as a guide, the Ion motor on your Sparta gives about 40NM torque, roughly on par with a Bafang SWX02 geared hub, more powerful than the Bafang SWX and less than Bafang BPM. The SWX02 is cheaper, lighter weight and more efficient at low revs. The Ion is quieter.

 

[anotherkiwi]

Good info!
Is the future for rear hubs over?'he says with troll hat'? I thought hubs had less moving parts, lighter, less friction and so more reliable and efficient?

so...I still have to decide between a rear hub with derailer OR mid-drive with hub gears for this road bike build. I like the rear-hub for the above reasons, but like the midDrive for simplifying the rear wheel, making it stronger and centring the weight (so i have the option of putting the battery on the rear rack)

No the geared rear hub has a long and happy future. It will require torque arms on an aluminium frame and some dropouts are "difficult" for bog standard torque arms. You also have to enlarge the dropout to fit the hub motor axle which is bigger. Torque arms make changing a flat a bit more complicated.

I would say for a trekking style bike with larger wheels and carrying full panniers etc. etc. my vote would be 50/50 between hub and mid-drive. A hub gearbox and easy changing of tubes would be the plus side for the latter. On a light weight road frame the mid drive would win hands down because of the ease of mounting it on the bike. A tiny sub 2 kg rear hub would be a second choice - just for 0-25 km/h off the line and help on hills. Tiny bottle battery with hidden Bluetooth controller to keep wires to a minimum.

I am just a few days of being able to compare both systems on the road. Then they won't really be comparable because I am moving from 26" wheel to 28" wheel.

 

[hygroovy]

In many ways, hub motor vs mid drive, is simplicity vs flexibility. A front mounted hub motor is as simple a conversion as you can get really, cheap and low maintenance. If I lived somewhere really flat I'd get a hub motor no problem.

But for hilly areas, and a range of gearing to keep the motor spinning properly, I'd go for mid-drive. It can be a fiddle to get it set up as you want (with different brake/drop out options this can be the case even with hub motors), but that's true of all conversions. And there's increased wear on the drivetrain (chains, cassettes etc.) But it has the added advantage of keeping all the weight centralised too.

For most applications, I think mid-drive has the edge for me. But you pays your money as they say...

 

[yojimbo]

Well just to throw in my tuppence. I am building a roadbike with 250w front geared hub and a small 24v 8.8ah battery. The kit was cheap enough, until I bought a new controller and lcd to make it work right, oops. Its a project of curiosity rather than trying to build an ebike for daily commute etc. I dont see front hub traction as being an issue, a road bike loads the front wheel and its only 250w, but we'll see. I bought some cheap saracen steel forks to use so I dont have to fear snapped dropouts, and built the motor into an Exal LX17 rim. So its not exactly race, but its sturdy, tyre is 25mm, I'll probably find out tonight if its going to spin.

Mid drive would be nice, but ironically, it does rather limit the the gearing and also adds to wear and tear on the gear train, shifting gears becomes a real issue if you are stepping through them regularly, so its horses for courses. I know the geared hub, especially in the hills where I am is less than ideal, but it will be interesting to see how it fairs. I only want the motor as a leveller for my lack of fitness and being a chubber. The BBS02 in my Schwinn OCC Stingray build will power me up and down the hills with ease, but at the cost of ah of course. Likewise the 1kw motor in the MTB, although I still have to work that hard on some hills as a direct drive is so inefficient at low speed. The road bike is hopefully going to be similar, I'll have to work hard to climb, but the motor will take an edge off. I may even limit the speed to something like 10mph, so its only engaging on PAS when really needed and once at speed its for me to do the work.

 

[PH001]

I may even limit the speed to something like 10mph, so its only engaging on PAS when really needed and once at speed its for me to do the work.

That's how I now run my 1000W Stealth and love it that way.