Will my forks take a front hub motor?

[photobike]

I have just replaced my front wheel with a 700C Swytch motor on a German style (Staiger) touring bike with suspension forks which also has the Rohloff hub on the rear. I have a Brompton with Swytch, a 3spd Pashley with a Tongsheng mid-drive and have had 2 Fazua mid drive bikes as well. I find the newest arrangement with lowest assist to be the most pleasant to use of the lot.

[Cowsham]

After all of that, closer inspection of the forks show they are aluminium alloy and not steel! I had assumed, given their graceful shape and the fact that the rest of the frameset is made of steel, that the forks were also steel.

Since they have 9mm QR dropouts, and the YosePower motor (which I am currently tending towards) has a 10mm axle I am looking for new forks. I really don't fancy filing down the drop outs on aluminium forks, even if they are quite beefy at 6mm thick.

But to summarise (bits of) the thread above: decent steel forks should generally be ok with a 250W hub motor, even if I have to file out the dropouts by a millimetre?

We ( my brother and I ) went for the yose power kits. His was the first one and was front hub. His bike was an old Giant town bike with aluminum forks. I didn't have to file out the dropouts but we did fit a torque arm fashioned from a small piece of aluminum strip -- very easy to do with a hacksaw and a drill a few minuits work.

I was so impressed by his yosepower bike conversion I bought a second hand carrera subway 2 ( with the hydraulic disc brakes -- cos I prefer them ) and put a yose rear hub kit in it. The bike cost £200 ( as new ) and kit £400 so my ebike cost me £600

The only 2 criticisms I have of the front hub is that it will exaggerate any slack in the head stock bearings and eventually make that worse and the potential to wash out the front into corners.

Though the second problem can be managed with careful riding and brake switches to cut the motor as you apply the brakes.

( in most pedal rotation sensing systems it takes a second or so for the system to sense you've stopped pedalling and the motor will run on a little dragging you deeper into the corner than you'd have liked -- in my opinion brake sensors are essential on cadence sensor ebikes -- I've not had any experience with toque sensors but there is a chance the same applies ie the processor may take a moment to work out your not pressing down as much as you approach the corner )

The head stock jerking each time the power kicks in would annoy me so I went for rear hub motor which is brilliant -- I've used the subway as a shopping bike and sometimes commuting ( on hot days which there haven't been many of this summer or when I'm just too tired ) have it for 2 years with no problems or range drop -- it's a great tool and I wouldn't be without it now. ( my brothers front hub is a year older )

As for yosepower I can highly recommend it you can buy every little bit -- even the reduction gears that go inside the hubs ( I think these are plastic which makes them very quiet and touch wood no problems yet. )

[Galactic]

I have just replaced my front wheel with a 700C Swytch motor on a German style (Staiger) touring bike with suspension forks which also has the Rohloff hub on the rear. I have a Brompton with Swytch, a 3spd Pashley with a Tongsheng mid-drive and have had 2 Fazua mid drive bikes as well. I find the newest arrangement with lowest assist to be the most pleasant to use of the lot.

Thanks for that, I had been secretly lusting after a Fazua (specifically Riese & Müller's UBN range) after reading Cugel's posts about them but find it difficult to justify the outlay given I have a much loved and well worn bike already. So it's actually rather reassuring to hear that you rate a front hub motor despite also having a Fazua.

in most pedal rotation sensing systems it takes a second or so for the system to sense you've stopped pedalling and the motor will run on a little dragging you deeper into the corner than you'd have liked -- in my opinion brake sensors are essential on cadence sensor ebikes

This is interesting, I had been debating with myself whether or not to fit the brake sensors (I have Magura hydraulics, so I'd have to order the extra bits and just gluing the sensors onto the brakes seems a little insecure). I shall reconsider.

Thanks for all the reports of experiences with the kits. I shall probably go for the Yose, but am still looking closely at the other options.

[Cowsham]

Yose sell the Reed switch ( switched by a magnet on the lever ) sensors separately for about £25 ( maybe more now since our currency devaluation over the last couple of years ) again plug and play with the connectors that run up to the handlebars. I cable tied mine under the trigger shifters and used black insulating tape to secure the magnets to the levers --
It's a bit of fiddling around trying to get the right positions -- took me longer to do that than fit all the rest of the ebike conversion kit. This has stayed in place for 2 years now. There is a sticky back on the Reed switch but I wouldn't trust that alone. A bit of faff but at least the switches are out of the weather being completely enclosed whereas you couldn't say the same for the normal brake switches supplied. ( I'm always thinking of water proofing living in NI where it rains almost constantly )

( put some self amalgamating tape around all the connections -- they are first class but I always use that type of tape anyway -- you'll have to cut it to get at the connectors again but it's a small price to pay for total water tightness. )

[Cowsham]

As for range my rear hub will do 60 miles on a 13ah 36v battery on level 1 but level 5 power will cut the miles down to about 35 which is plenty for me as my commute to work is 15 miles each way and only use level 5 if I'm a bit on the late side.

I've come to the figures above with my commute using the power 100% of the journeys. Ie it'll do two runs to work and back ie 15 x 4 miles on level 1 and one round commute on level 5.

My brother bought the 17.5ah ( iirc ) battery which fits the same housing as the 13ah and he managed to push over 150 miles out of his old town bike on the lowest setting. This was his best mileage with him being very conservative with power use ie switching it to zero on the flat or whenever he could and running it down to just 1 bar ( out of 5 on the display )

[Galactic]

I cable tied mine under the trigger shifters and used black insulating tape to secure the magnets to the levers --

Would it be possible to see a photo of this? That would be very helpful.

As for range my rear hub will do 60 miles on a 13ah 36v battery on level 1 but level 5 power will cut the miles down to about 35 which is plenty for me as my commute to work is 15 miles each way and only use level 5 if I'm a bit on the late side.

This is useful stuff, good to see some real-life numbers on battery range. What kind of terrain/wind conditions and weight (cycle, you and stuff carried) are we talking here? And are running the battery right down with these range figures, or keeping the usual 10-20% in reserve?

[stodd]

You may find the 10mm on the motor has one flat edge (antitorque) and will fit the 9mm dropouts.

Or 2 flat edges.
Not only will there be no need to file out the dropout, it would be a bad idea as it would stop the anti-torque behaviour.

[Cowsham]

As for range my rear hub will do 60 miles on a 13ah 36v battery on level 1 but level 5 power will cut the miles down to about 35 which is plenty for me as my commute to work is 15 miles each way and only use level 5 if I'm a bit on the late side.

This is useful stuff, good to see some real-life numbers on battery range. What kind of terrain/wind conditions and weight (cycle, you and stuff carried) are we talking here? And are running the battery right down with these range figures, or keeping the usual 10-20% in reserve?

Leaving 1 bar so down to the 36v (maybe 36.1 -- can't remember don't let it down that far often ie I put it on charge when I get home each night normally but tested the range a few times ) on the 2 x 30 mile round trips on level 1. The level 5 single round trip there's usually 2 bars at least left over ( I think around 37v left will look the volts next time ) when back home hence why I think I could do another 5 miles easily on level 5.

I'm carrying one pannier on the rear rack with my backpack inside containing all food I'll need for my work day plus some clothing and tubes etc then there's a small frame bag with all my bike tools patching outfit and pump in. Funnily enough the forks are steel while frame is aluminum on the subway. So not a light bike by any stretch of the imagination but I purposely choose it cos it's sturdy and it's square taper bb for this ebike conversion. Tyres are 2" schwalby land cruiser type so not skinny slicks either.

( my brothers old town bike has 700c 28mm treaded tyres )

[Cowsham]

I cable tied mine under the trigger shifters and used black insulating tape to secure the magnets to the levers --

Would it be possible to see a photo of this? That would be very helpful.

I'll take one tomorrow in the daylight

[stodd]

Leaving 1 bar so down to the 36v (maybe 36.1 -- can't remember

1 bar is probably quite a bit lower, maybe 34v or even 32v

[Cowsham]

Leaving 1 bar so down to the 36v (maybe 36.1 -- can't remember

1 bar is probably quite a bit lower, maybe 34v or even 32v

No -- not on my bike the voltage starts off at around 42v and slowly erodes to about 36v. At 100% charge they are around 42v and the lowest voltage you'd want to be down to is about 32v where hopefully the BMS would cut power from the battery before damage is done. I always like to leave more than 20% hence the 2 bars left after a days commute ( charging inside a steel wall box outside the garage after the battery has cooled if I've done 15 mile commute home on level 5 --
not often cos I can take my time on the way home obviously )

[PJ53]

I have a front hub motor Swytch kit fitted to a Boardman Hybrid bike with a carbon front fork. It does have a torque arm fitted and has given me many problem free ebike miles. I do use the motor only for assistance though on a low power level, usually 1. I do not put it on level 5 and then only soft pedal, well maybe sometimes

[Cowsham]

I cable tied mine under the trigger shifters and used black insulating tape to secure the magnets to the levers --

Would it be possible to see a photo of this? That would be very helpful.

I'll take one tomorrow in the daylight

Sorry I forgot to get that photo -- better late than never though

[Galactic]

Sorry I forgot to get that photo -- better late than never though
20241013_172223.jpg

Thanks Cowsham. Quick question: where did you put the magnets? I can't see them in the photo.

[Galactic]

EDIT: posted this on wrong thread, it belongs in the thread PAS/Hollowtech: viewtopic.php?t=161120 )

So, I've got the magnets for the PAS sensor (PASensor?) attached to the Alfine cranks. I was inspired by this Ukrainian fellow: https://www.youtube.com/watch?v=ZVVEFk5EiKY . He cut up a plastic canister (presumably HDPE?) and screwed that to the inside of this cranks, then screwed on the magnet ring to the piece of plastic using self-tapping screws.

As he said in the video (use auto-translate subtitles if your Ukrainian isn't what it used to be): use what you find around the house. I couldn't find a suitable plastic canister that was big enough, but I did find some lovely stainless steel 5l olive oil canisters. I made a template and snipped out the thin steel. I didn't do a good job of it (old tin snips with serrated edge that I couldn't sharpen even though I filed away at them for an hour), but it all works and I shall cut out another holding plate after a thorough testing. The advantage of the steel compared to plastic is that the magnet ring doesn't need any further fastening.

The magnets are about 4mm from the sensor, but it seems to work well enough (plug the sensor into the battery, turn the cranks and check the wee red light flickers on and off whenever a magnet passes). If I feel I need to close the gap a little I can put washers on the chain ring screws. I could attach the plastic holder that comes with the magnet ring, that will give me another mm or two, but then the magnets aren't as secure and I'd need to glue the magnets to the holder and somehow attach the holder to the steel plate.