Retro fitting to tandem?

Electrically assisted bikes, trikes, etc.
reohn2
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Re: Retro fitting to tandem?

Postby reohn2 » 18 Jul 2018, 8:24pm

SimonCelsa wrote:Thanks for that Reohn2, I'll do a little more research before pulling the trigger but think the front wheel hub motor is the way to go for the tandem. Still feels a bit expensive but don't think you'll get much for less than £500.


No I don't think you get anything worth having for less than £500.Ours cost £800.
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hemo
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Re: Retro fitting to tandem?

Postby hemo » 19 Jul 2018, 6:18pm

Mxus XF07 hub kit is a bit weedy and may prove to be a bit gutless on a heavy tandem when it comes to hills.

Woosh are moving a bit more in to hub kits I believe for the future esp with the EU slapping 83.6% anti dumping tariffs on all Chinese mainland e bikes.

Speak to Woosh and see if they have any plans for a 48v 250w front wheel Bafang hub kit.

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SimonCelsa
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Re: Retro fitting to tandem?

Postby SimonCelsa » 20 Jul 2018, 5:53am

Yes thanks Hemo, I did think the XF07 may not be quite the best option for a tandem. I am still very much in the research phase and need a bit more reading up on the subject so as to ask the right questions. Give Whoosh their due, they didn't actually recommend the XF07, it was the only 700c front hub on their site. However I think they may do a front hub 36V 350w BPM kit which may be more suitable. Still seems like a good wodge of cash for something I may not use that often, it may be cheaper to engage a personal trainer for the wife for a couple of months!

hemo
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Re: Retro fitting to tandem?

Postby hemo » 20 Jul 2018, 9:26am

The Bafang BPM hub is awesome it has immense torque, the rpm winding is low (201rpm load speed) so ideal for a heavier bike or rider combo. If you aren't to bothered about the 350w rating then it has to be one of the best hubs on the market. A shame is marked 350w instead of 250w.


They are ideal fo steel front forks but not so good for some aluminium forks even with torque arms.
The torque sanpped the drops outs in my RS reba's after a bout 1k miles but in my 700c suntours (2k+) I had no issue as the drop out's were so much stronger and meatier.

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SimonCelsa
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Re: Retro fitting to tandem?

Postby SimonCelsa » 20 Jul 2018, 3:06pm

That's good to know, I'll keep the 'snapped dropouts' anecdote away from the wife!

The tandem is a 10 yr old cheap & basic alloy Viking Tarantino with cromo forks. These seem pretty beefy and are certainly not lightweight. It hasn't let me down yet. I'll get back to Whoosh shortly to confirm they actually fit these BPM hub kits to a 700c front wheel, the website only mentions the 700c rear. Still in the contemplating stage.....I sometimes work away for extended periods and can't be sure the wife or kids will remember to 'care' for the battery!

stodd
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Re: Retro fitting to tandem?

Postby stodd » 2 Aug 2018, 6:50pm

I fitted the Woosh XF07 front hub to a Viking tandem a bit over a month ago. Woosh suggested the SWX02 48V 250W rear hub kit but didn't have it in stock for 700/622 wheels then. They do now I think (at least they are advertising it). The XF07 helps with the hills around here (Winchester, not too extreme); we generally use level 2 (of 5) assist and level 3 on the hills and it does all we want of it. We are getting around 35 miles per charge on the 13aH battery.

We are very satisfied. If I were fitting now I would probably get the SWX02. Battery only 12aH, but as it is 48v that is equivalent to 16aH 36v battery.

I have had an issue that the rim that comes with the XF07 rim does not like my Marathon Plus or Marathon Plus Tour (you may have seen http://www.pedelecs.co.uk/forum/threads ... lus.32147/) Could be my fault, but I've fitted these tyres on several bikes before. (I suspect you are in touch with them, Tony just accidentally called me Simon in a reply on that forum)

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SimonCelsa
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Re: Retro fitting to tandem?

Postby SimonCelsa » 4 Aug 2018, 5:36pm

Some good info there stodd. There are a fair few hills up in this neck of the woods around Inverness-shire and I would look for a circa 50 mile range ( I know this is dependent on so many things!!) so still thinking more along the lines of the 350 W BPM front hub. Just a bit concerned over whether the front forks are man enough. They are steel and look OK but the actual dropouts aren't particularly inspiring. I'll have to think of some good non destructive tests to boost confidence before taking the plunge and ordering.

stodd
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Re: Retro fitting to tandem?

Postby stodd » 5 Aug 2018, 6:27pm

I'm sure Woosh have mentioned these and you are probably aware anyway, but ...

Don't forget the 350w is not technically legal.
The 350w comes with torque arms, so the Viking dropouts should be adequate.
Despite being nominally 250w, the SWX02 probably has as much torque and as much power for normal use as the BPM.
But the SWX02 is rear only; more awkward fitting, probably needs new freewheel, ...

We went on a short morning ride before it got too hot (less of a problem for you?).
The motor made all the difference on the hills.

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SimonCelsa
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Re: Retro fitting to tandem?

Postby SimonCelsa » 6 Aug 2018, 9:16pm

Did you fit torque arms on the XF07?? I see the sales blurb states you don't need them.

I'm leaning more towards the XF07 with 17Ah battery now, I still like to pedal but need a hand with the wife on the back sometimes. Hills here are not really that bad, mainly longish and not too steep. What did you use for the pedal sensor, I've just fitted 127.5mm BB's fore & aft and still not sure what is the best option??

I am thinking of fitting the battery here;

tandem batt pos 1.jpg


so will need to fit a couple of rivnuts if I can get the drill in!!

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SimonCelsa
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Re: Retro fitting to tandem?

Postby SimonCelsa » 11 Aug 2018, 8:53pm

A quick update.

Took the plunge & ordered the 'Woosh' XF07 front hub conversion kit with 17Ah battery pack for the tandem.

Fitted it all tentatively today & took it for a quick 20 mile jaunt with the wife. I am a reasonably fit & experienced cyclist but unfortunately the wife has never quite mastered the balance for solo cycling. Having spent a while in hospital she has also lost a fair bit of fitness thus I have recently found even quite mild uphills a bit onerous, especially with a nipper in the child seat. Although I was advised that the XF07 probably wasn't the best option for a relatively heavy tandem I am very very pleased with the performance today. Admittedly we chose a gently undulating route and there is a certain 'novelty' to the whole thing but 'wow'!!......why do people need cars?

Again, very pleased and I can't fault the assistance from staff at 'Woosh' who have displayed great customer service, highly recommended.

The only real 'difficulties' were:

1. having to drill into the frame to fit a couple of rivnuts for the battery/controller (had to drill at a bit of an angle as the location was a bit tight - I realise right angled drill attachments are available cheaply but I am a little impatient).

2. Initially I couldn't get the hub between the forks as the clearances are very very tight. 100mm OLN but the tandem has very fat forks. Managed to just get clearance by manipulating the spacer washers & removing the not used disc brake ring/bolts (good advice from Woosh here - I was about to give up & purchase some different forks!)

3. Having to get rid of the original integrated brake/gear trigger shifters & source some separate gear shifters (eBay cheapies) to use with the Woosh supplied brake levers (motor cutout). Entailing rerouting all brake & gear cables which is a bit of a pain. In hindsight I would probably have been better ordering their 'hydraulic brake cut off' switches at £23 & retaining my original shifters! Ho hum.

4. One of the supplied cables, from the controller to the front hub motor was about a foot too short. Advised Woosh by email yesterday (Friday) afternoon & the new longer cable was with me this morning (Saturday). I am up in the Highlands, I think Woosh are in Essex!!

5. Fitted 2 new (very cheap, probably I will regret this) longer square taper bottom brackets 127.5mm to facilitate fitment of the pedal assist sensor.

So, on the whole nothing too extreme. I hope once the novelty wears off a bit I am still as pleased with the outcome as I am at the moment. It really does take the sting out of the hills but you still get a good workout if that's what you want. I don't think I would fit a motor to my solo steeds but for the tandem I wish I'd done it a long time ago!

A few pics if anyone interested, still not finished securing all the cables etc, job in progress:

vtandem bars.jpg


vtandem left side clearance.jpg


vtandem right side clearance.jpg


vtandem layout.jpg


Any comments or constructive criticism welcome.

stodd
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Re: Retro fitting to tandem?

Postby stodd » 13 Aug 2018, 5:05pm

Glad it went well and I hope the XF07 continues to give enough power. We normally only use level 2 of 5, and level 3 for the hills with our XF07 on the tandem.

Our fitting was a bit easier than yours. A few comments: mainly in case it helps others with similar issues.

1. We currently have the battery fitted using just two bolts into the existing bottle cages: planning to add an extra with a rivnut some time, or even with a simple strap. I had to put in washer to tilt the battery a fraction to stop occasional rubbing against the chain.

2. Woosh sent the wheel so that one of the special washers was inside the fork and the other outside; that made it exactly the right width and well centred. It seems fine without torque arms as long as the special washers are properly seated.

3. We used the hydraulic switches to keep the original shifters.

4. Woosh got all our cable lengths right first time ... the speed they provided yours confirms the many comments about their good customer service.

5. The PAS fitted our existing front bottom bracket (just)

6. I can't be sure from the picture, but make sure the cable is leaving the front hub pointing downwards to stop rain dripping in. (I noticed your post on Pedelecs about weather).

hemo
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Re: Retro fitting to tandem?

Postby hemo » 14 Aug 2018, 9:21am

For steel dropouts you can dispense with (T/A's) torque arms but make sure the tabs of the (AR's) anti rotation washers sit all the way in the drop out, sometimes you may have to file the drop out 2 or 3mm deeper and then make up tight.


If fitting in to ali forks you would be a fool not to use one or even two T/A's, AR wahsers alone will not suffice. Drop outs may be fine for a 1 or 2K miles but eventually the torque will cause meal fatigue and drop out will fail.

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SimonCelsa
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Re: Retro fitting to tandem?

Postby SimonCelsa » 15 Aug 2018, 6:43am

Valid points; I installed the front hub cable with a good 'drip' loop, have blanked with grub screws the exposed holes where I removed the disc rotor bolts, & fitted both anti turn washers in the steel dropouts (one side only needed a bit of filing).

All should be good, now mulling over what will potentially get 'shorted' in a downpour....plakky bag over the throttle & maybe a shower cap over the battery.

75 miles on the first charge (although I think the speed & hence Odometer is reading a bit high ~ 15% or so). Remain happy. I still do quite a bit of moderately strenuous pedalling so that range is a bit meaningless really!