Why 10mm flats on front motor hubs?

[NickJP]

Why do front motor hub come with axles that are 10mm across the flats, when fork dropouts are sized for 9mm axles? I've now done five ebike conversions using front motor hubs, and on every hub I had to file down the flats until the axle would fit in the fork dropout.

[bikes4two]

Maybe 10mm is the optimum outside diameter for a steel axle that has a hole right through its centre that is large enough to carry the hub motor electrical cables?

[hercule]

Out of interest did you file down the axle to fit the dropouts, or file the dropouts to fit the axle?

[NickJP]

Out of interest did you file down the axle to fit the dropouts, or file the dropouts to fit the axle?

Read last sentence of my initial post...

[NickJP]

Maybe 10mm is the optimum outside diameter for a steel axle that has a hole right through its centre that is large enough to carry the hub motor electrical cables?

Yes, but seeing that the manufacturer machines flats on the axle anyway, why not make them the correct distance across to fit standard dropouts?

[Bonzo Banana]

I don't know why they do it except I guess manufacturing of the hub motor is probably all set up for 10mm axles front and rear and it does add extra strength to the axle which means less likely to bend it. Front hub motors have a reputation for greater reliability and if they are using the same axles and bearings as the rear hub motors which have a lot more weight on them then it makes sense why front hub motors are more reliable. So i'll take it as a positive despite having to file the fork dropouts. Also its dodgy to file down aluminium frame dropouts but normally pretty safe to file down steel fork dropouts a bit. If you buy something like a Carrera Subway and want to convert it to electric you have to file the rear dropouts for a hub motor and use a torque arm to secure the hub motor but as long as its not too powerful you don't need a torque arm for the steel front forks. This makes punctures far easier to deal with. I personally much prefer front hub motors generally.

[bikes4two]

...... I personally much prefer front hub motors generally.

A bit of a sideways lean on this thread, but what front hub motors have you used and which one is your favourite and why?

I'm on the lookout for my first hub motor and finding one with a chrome/silver finish is proving difficult (and I don't particularly want to spray paint a black one) - any clues?

The front hub motor on a Swytch wheel is nice and shiny (Aikema 100sx I believe) but I don't want that kit and in anycase I'd like to build my own wheel and battery (using a KT Controller/display) so I'd be happy to buy a second hand one of them if all else fails.

Thanks.

[Bonzo Banana]

...... I personally much prefer front hub motors generally.

A bit of a sideways lean on this thread, but what front hub motors have you used and which one is your favourite and why?

I'm on the lookout for my first hub motor and finding one with a chrome/silver finish is proving difficult (and I don't particularly want to spray paint a black one) - any clues?

The front hub motor on a Swytch wheel is nice and shiny (Aikema 100sx I believe) but I don't want that kit and in anycase I'd like to build my own wheel and battery (using a KT Controller/display) so I'd be happy to buy a second hand one of them if all else fails.

Thanks.

Just general hub motors including direct drive hub motors and geared hub motors but nothing proprietary like a Swytch kit. I prefer having them on the front for dealing with punctures, keeping the original gearing on the rear wheel and having long spokes on the rear wheel for better suspension and easier pedalling. Easier fitting, no need for a torque arm normally. Quite like the heavier steering and like the bike having dual powered wheels for better grip on some surfaces. Also even's up tyre wear and reduces wear on the hub motor as less weight on the bearings. If you have regenerative braking (I don't) then as you go down hill more of your weight transfer to the front wheel so its not such an issue anyway that the rider's weight is not directly above the wheel. Also I'm a heavy rider so some of those benefits may not be applicable to lighter riders but I think most are. In theory there could be less grip on a powered front wheel but I'm heavy, don't have a powerful hub motor and use thick tyres so not really an issue. Another benefit is its easy to return the bike to a normal bike for some riding. Swop the front wheel out for a normal wheel remove the battery and most of the ebike component weights are gone.

[stodd]

[like the bike having dual powered wheels for better grip on some surfaces.

I agree, very helpful on a tandem. Also the different weight distribution on a tandem reduces the downside of front motor slipping on loose surface hills.

[bikes4two]

Thanks for sharing your views - I am looking for a front hub solution on our tandem - anything else won't work as there's a Rohloff on the rear wheel and two eccentric bottom brackets so no mid drive conversion either.

I know front hub motors can lack the power of some rear ones (apparently) but that shouldn't be a problem for us as we're still hearty peddelers, just a bit tarnished at this end of the age spectrum - lol.

[stodd]

We have XF07 on front of our (basic Viking) tandem for just over 6 years. Helps a huge amount but we would appreciate more on some hills. Once it starts to slow down it loses efficiency quite quickly, so we still often really need our fairly low lowest gear. I've learned to select 4 or 5 of 5 and get as much speed as we can well before a hill. That helps a lot, but still slows down and leaves more work than we'd like for longer hills. We've had a kneecap broken right through and a completely detached patella tendon between us in the last few years which haven't improved our pedal power. Mostly we ride in 2 of 5.

If I had the option I'd go for a motor that wasn't that much more powerful, but was wound for maximum efficiency around 10mph. That would mean it didn't help on the flat that much, but was much better for hills.

https://ebikes.ca/tools/simulator.html? ... h&grade=10

[NickJP]

If I had the option I'd go for a motor that wasn't that much more powerful, but was wound for maximum efficiency around 10mph. That would mean it didn't help on the flat that much, but was much better for hills.

TopBikeKit sell at least some of their motor hubs with choices of reduction gear, depending on whether you want them for flat ground or hills. For example, I bought one of these hubs in the low RPM version for installation on our tandem:

https://www.topbikekit.com/144kg-akm75s ... p-905.html