Using existing wheel on hub conversion

[richardadc]

I'm considering buying a Cute Q100 front hub for a Tern P9 I'm considering. I was just wondering if it's possible to implement this in an existing wheel? The Turn wheels have a white rim so ideally i don't want to make the bike look odd and change this.

Thanks

 

[Deleted member 4366]

If it has 36 spokes, no problem. If it has 32 spokes, they do a rear Q100CST 328 rpm. Any other number of spokes and you're out.

 

[trex]

20 spokes, but the BB is standard, that's why I recommended a CD kit.
I suppose one can drill the extra holes but you still need to find 36 special length white spokes.
The Tern has 32"-93" gear inches on 52T chainring, the BBS01 has 46T, translated to 30"-86" gear inches if fitted to the P9, still very comfortable to pedal.

 

[richardadc]

Thanks both. I wanted the weight advantage that the q100 would give. I was also considering a Tern p18 and that would not work with a cd kit. Lastly I wanted the possibility to switch it back to a normal bike as easily as possible just in case I want to ride it as a normal bike.

I think the spokes are still silver in colour - it's the rim that's white. If I do need an odd one is there anywhere I could get one done that offers a choice of colour?

 

[trex]

I think you can ask the supplier of the Q100 kit to fit it to a white rim. It's easier for them to do this than for you.
I agree that the Q100 offers reduced weight but by the time you add the rear rack battery, controller and wiring, the weight advantage is reduced and power and speed wise, the Q100 can't match a CD kit. The BBS01 can assist up to 24mph. Reversing a CD kit is no worse than reversing a hub kit. You usually have to undo the bottom bracket to fit the PAS for a hub kit. The time taken to do this is about the same to fit a CD kit, so CD kits are simplest to install (and reverse). The other advantage of the CD kits is you get to keep the wheelset, easier to deal with tyres.

 

[shemozzle999]

The verge s11i is the only one I have found from the off the peg range that would work with the existing BBS01 size crankwheel and give reasonable speed and cadence.

http://www.evanscycles.com/products/tern/verge-s11i-2014-folding-bike-ec032576

 

[trex]

but can you swap out the chainring on the BBS01 for the one on the Tern?

 

[shemozzle999]

You can use the BBS01 as supplied, they are both 46T.

 

[jhruk]

I don't know for sure but I suspect the Tern is similar to the Dahons in that it has a narrow front fork dropout. The 100mm wide Q100 might be a stretch too far in the short aluminium fork of the P9. If you want a front motor the 80mm wide Q85 would be a much better fit, and slightly lighter - I have one of these in a Dahon & it works very well. Alternatively, if you really wanted a 100mm front motor, it might be better to fit a steel fork, which are not expensive.

With regard to the rim you would really need one with the same number of spoke holes as the motor. The Q series front motors are normally 36 hole but I'm sure the Tern rim will be less, so wouldn't be able to be used unless you went for a very unusual lacing. You could buy another 36 hole white rim, but I doubt you'd find an exact match with the existing one.

 

[Deleted member 4366]

How are you going to get 24mph out of a BBS01 on a bike with 20" wheels? Is there something new? In my reckoning, you'd have to pedal at a cadence if 100. A normal cadence of 60 would give you 14.4 mph, compared with the present gearing, which gives 19 mph at a cadence of 60.

A Q100 won't fit in the front. I don't think a Q85 will either. It has to be a rear motor. The Q100CST will allow you to keep the present gearing, but it's a bit wider than the normal Q100, so a tight squeeze, but it will fit. You need a fair dish in the wheel IIRC.

 

[trex]

on my bike, the top gear gives 84 gear inches and I pedal flat out at just 24mph at around 110 rpm. The Tern P9 has 9 speed rear cluster, with 52T, 103 gear inches. If you could swap out the chain ring of the BBS01 for the Tern's 52T one, you should be able to do 24mph with slower pace.
Somebody made an adapter for it:

but I am looking for a 52T chainring made for the BBS01.

 

[shemozzle999]

For a non rack battery solution this Company makes a water bottle mounting adapter plate for the side entry style battery:

Plate:

http://www.ebike-easy.com/products/Parts/Batteries/ELFEi-Battery-Adapter.html

Battery, but can be purchased cheaper from other sources:

http://www.ebike-easy.com/products/Parts/Batteries/ELFEI-Standard-Battery-36V-9Ah.html

http://www.ebike-easy.com/products/Parts/Batteries/ELFEi-Long-Travel-Battery-116Ah.html

All these items are easily removed allowing you to return the bike to standard configuration at a later date should you so wish.

 

[shemozzle999]

Only problem that you would need to check is that the s11i is not an old model that was subject to a recall last year:

http://pedelecs.co.uk/forum/threads/tern-product-recall-in-usa.15282/

 

[richardadc]

D8veh, will a Q100 not fit even if I switch to steel forks? Regarding the Q100CST, if i switch to that I'd still be able to use the same 9 gears? The reason why i was thinking about front was because i thought i was limited to 7 gears.

Regarding the battery i was thinking about the frog case.

Trex, are you saying that an adapter is available to buy meaning i could still keep 52T on the Tern P9?

Basically my overall plan is to have the motor on the bike but everything else should ideally be removed in one go, either by a bag attached the front of the bike or something attached to the seat post. I don't want it to look like a typical electric bike with a big battery in a rack.

 

[trex]

With the adapter, you can keep your nicer Tern chainring. Alternatively, if you can find a 52T chainring made for the BBS01, it'll do the same job and you can keep the nicer Tern chain guard. I suppose you can always ask someone with a laser cutter if they can make you an adapter.

 

[Deleted member 4366]

With the Q100CST, you can keep your 9-speed gears. Here's one in my Dahon Jetstream P9. Why not a bottle battery? It should fit straight on yours. You need to get the S06S controller if you want the one that goes in the bottle:

 

[richardadc]

D8veh on the thread at http://www.pedelecs.co.uk/forum/threads/torque-sensing-build-for-tern-folder.17734/ you suggested that front drive would be better. Was this down to a different motor and in general which makes the most sense?

I've seen some suggestions that the q100 is underpowered and a bafang swxk is recommended? I'm not light.

At the moment the more I read the more confused I get.

 

[trex]

in general, front wheel drive is easier to fit, rear wheel drive feels more natural to ride, better grip and acceleration. Crank drive is the most expensive and best and you also have to put up with gear change noise at the sprocket but quieter than hub motors. Frog batteries are getting lighter so perhaps won't break like they used to, easier to fit than rack batteries. All kits are compromises.

 

[Deleted member 4366]

D8veh on the thread at http://www.pedelecs.co.uk/forum/threads/torque-sensing-build-for-tern-folder.17734/ you suggested that front drive would be better. Was this down to a different motor and in general which makes the most sense?

When I said that, I didn't realise that the Tern had the same narrow forks like the Dahon. I think that they're 75mm.

The Q100 has quite a lot of power. It goes pretty well with 18 amps and 44v. The Bafang can probably handle a bit more.

 

[shemozzle999]

If you are looking for a front drive solution you will need to change the forks.

I found this last year, specifically widened at the base for an electric motor, but didn't follow up on it and don't have any dimensions so you would have to ask via email:

http://simino.en.alibaba.com/product/383204133-210811029/electric_bicycle_20_fork.html