Conversion questions from a newb

[VillageIdiotDan]

Hi,

Really sorry to ask some basic questions - had a good look around the forum but couldn't find the definitive answers

My background is I own a steel 700c cyclocross on slick tyres for my largely flat 35 mile round trip commute. I average about 17mph on the way but slow down alot on the way back (headwind) hence why I'm here as it's putting me off doing it more than once a week.

I've discounted front hub as I've got a 12mm thru axle fork and don't want to change it, I've discounted rear hub as I'm on a 10 speed and don't want to change the shifters so am thinking a BBS01/02 mid drive.

1. Do you think I shouldn't have discounted front/rear hub so readily? I think with mid drive it's easier as I just have to remove the front derailleur and gear shifter. Agreed?

2. I'm still looking to work hard, just keeping up the average mph. I think 500w instead of 750w is plenty? 48v instead of 36v?

3. How do I know what battery I need to buy? Is it restricted by the wattage of the hub?

4. What's the deal with kits coming with brake levers, can't I just keep my existing brake levers as they're drop bar type.

5. Money's tight, I plan to buy off eBay, where else would you recommend?

Any other common pitfalls that you'd warn me about please?

 

[Woosh]

my XF08C kit takes most 10-speed cassettes.
This said, there is no real reason why a 500W kit would do better as you are used to ride at 17mph.

 

[vfr400]

1. Yes, but if you get a hub- motor. You need to make sure it has the right speed.
2. 48v normally means 750w if you go for a mid motor. With a hub-motor at 48v, a 250w motor will be powerful enough.
3. The battery needs to be able to give enough amps for the motor controller. Whatever controller amps you have add 5 to the battery, so for a 15 amp controller, you need a battery that can provide 20 amps, etc.
4. Yes
5. A torque arm if you get a hub-motor.

 

[VillageIdiotDan]

my XF08C kit takes most 10-speed cassettes.
This said, there is no real reason why a 500W kit would do better as you are used to ride at 17mph.

Hey Woosh, thanks so much for the quick reply. Ah, well, I would probably prefer the low maintenance of a rear hub. I know my cassette is a Shimano 10-speed 11-32T but then I guess I'd just buy a new one to put on the new wheel if you could recommend one that you've seen fit pls?

Sorry, ref your comment on the 500w, do you mean the 250w of your xf08c would probably be sufficient power wise? I guess my only concern is it's all rural so it'll be the top end ave speed that I'm trying to influence.

I'm away at the mo, will have a good look at the website when I get on my laptop

 

[VillageIdiotDan]

1. Yes, but if you get a hub- motor. You need to make sure it has the right speed.
2. 48v normally means 750w if you go for a mid motor. With a hub-motor at 48v, a 250w motor will be powerful enough.
3. The battery needs to be able to give enough amps for the motor controller. Whatever controller amps you have add 5 to the battery, so for a 15 amp controller, you need a battery that can provide 20 amps, etc.
4. Yes
5. A torque arm if you get a hub-motor.

Really helpful, thanks vfr! - especially re controller v battery amps. Do I need a torque arm even if it's rear hub? On a steel frame?

 

[Woosh]

Hey Woosh, thanks so much for the quick reply. Ah, well, I would probably prefer the low maintenance of a rear hub. I know my cassette is a Shimano 10-speed 11-32T but then I guess I'd just buy a new one to put on the new wheel if you could recommend one that you've seen fit pls?

sure, you can have the same cassette as your current one.

Sorry, ref your comment on the 500w, do you mean the 250w of your xf08c would probably be sufficient power wise? I guess my only concern is it's all rural so it'll be the top end ave speed that I'm trying to influence.

I'm away at the mo, will have a good look at the website when I get on my laptop

the maximum setting of the controller tells you how much input power it will take. The XF08C is supplied with 17A controller, that means when you climb a steep hill, it will draw as much as 17A from the battery.
The controller will pull 36V * 17A = 612W from the battery. Some of that power will turn into heat, roughly 30%-35% when you climb a steep hill. That's why it should be a trade off, more Amps = more heat = shorter life expectancy, especially for the battery. 17A is a good compromise, you get about 400W-450W mechanicial power, 200W-250W heat.
A 500W kit typically runs with 25A controller.

 

[vfr400]

Really helpful, thanks vfr! - especially re controller v battery amps. Do I need a torque arm even if it's rear hub? On a steel frame?

You have to make a judgement on how strong the drop-outs are. If you have those long ones that are angled up at about 45 deg, they'll probably spread without a torque arm. Normal vertical drop-outs would probably be OK, but it's not possible to be sure without seeing them.