Suspension vs. Bigger Tires

[reluctantsuburban]

I'm not sure you'll get more bang for buck converting vs buying something factory built in that price range - by the time you've bought a conversion kit, battery, fitted forks +/- upgraded brakes +/- eventually upgrading the wheels , that budget will evaporate- and you'll still have a frame designed for normal bike forces. EVERYTHING on my giant full e pro emtb is just so much beefier than the equivalent parts on my norco optic or giant trance oldmtb's - spokes, rims, hubs, forks, frame, etc - I can literally feel the frame and wheels of my norco flex when I corner hard ( I think they are designed to flex a bit) . Even the tyres are extra heavy duty ( thicker and fatter so more puncture resistant but heavier / more resistance when riding) . You'll see the difference when you ride the bulls bikes.

The main advantage of custom building is you can transfer the ebike parts between bikes as your needs clarify, but the factories seem to be putting out some very competitively priced bikes - especially if you don't mind buying discounted 2018 models ( 2019 range are just being released )

Thanks @PDoz - I had not considered the difference in frame and components. That is an interesting point--I had assumed that as long as I was conforming to Class 3 speed standards, I would not be over-stressing the bike. Sounds like that may not be the case? To your point, I hope to feel the difference when testing. I find it difficult to tell the difference in frames from a spec sheet online.

Would you think, then, that something like the Juiced CCS would be a better frame/component set than converting, say, a standard Kalkhoff frame that I add a kit to?

 

[reluctantsuburban]

As an active DIY'er, I'm currently riding a production e-bike/DIY'er hybrid. I had built a 29'er conversion, starting with a brand new bike. Loved it after working out all the bugs, but didn't care for the high step over height (pretty snug on my 6'2" frame). This eventually led me to Rad Bike's City model. After purchasing and riding it for a couple of weeks under a lot of conditions, I found I loved the bike itself (I bought the small frame, so stand over height is no longer an issue, great compromise vs. a step through!), but found the electrical/electronics lacking in just about all areas as I was used to much more robust from the earlier conversion.

So I stripped the 2 week old Rad City of it's electrical and installed a complete 1500w DD conversion kit w/26" wheel. VERY easy install. The only thing I used over again was the battery. Now we're talkin! LCD3 display for tons of custom setup features, cruise, regen, 180mm brakes, 2.3 tires, HD welded on rear rack with hard points for a front rack, double wall rims front and rear, and on and on. PLENTY of power, and ability to customize everything from max amperage available to PAS levels. Price point? Well under 2k. complete.

Hi @AHicks --this is super intriguing to me, I don't that I ever would have considered it. So, I'm understanding you correctly, you subbed in your own hub motor kit which had its own bms/controller/wiring, etc? All that you retained is the RadCity battery?

I think the thing that is confusing me here is how you were able to take advantage of your 1500W speed--that is, unless you provided your own controller? What kit did you end up using? I am very interested to know more, if you'd be willing to provide links, I would greatly appreciate it!

 

[AHicks]

Speed was not my top priority. I'm good with 20mph sustained (no commuting for me). For me it was more about an enthusiastic launch when crossing a busy street or something. Lotsa power, but nothing really sustainable. It was the only way I could make the stock Rad battery, which is wired with 14awg wire internally (good for 20 amps or so sustainable, or about 1000 watts, but much more for a short blast across a street for instance). The way I did that was to limit max wattage level to 1100 or so in setup.

Testing done originally, prior to setting up the max wattage and 20mph speed limit, had the bike accelerating enthusiastically up to about 35 mph before running out of room - and yes I'm a big guy (320lbs). I doubt 40 would be difficult. Yes, Big grin. Edit: motor was pulling a little over 1600 watts here!

40 mph still possible, but you would need to sturdy up the electrical - starting with a rewired battery at minimum. That 14awg would have to go in favor of something like 10awg. and then I'm not sure if the individual cells would stand up to a lot of abuse. The battery certainly wasn't speced out for it originally!

I ended up using a KT based (LCD3 display capable) 12 mosfet 35 amp max controller that features the ability to work with no Hall sensors in the motor (KISS logic). It's the smoothest and quietest of the 4 I've had on it. Why 4 is another story, not relevant here. You can pretty much order out your own kit, other than the motor, right here, at very good pricing.
http://www.pswpower.com/ven.php?cargo.2016-3f-28ym

I used a 1500 watt motor because it was only a couple bucks more than the 1000 watt. It also features wires that come out the side of the axle vs. the end, making them less vulnerable to my way of thinking. Leafbikes has a pretty good reputation, offering reasonably decent support (still Chinese/on the cryptic side), and maybe not the least expensive. My first 2 DIY bikes were built with his conversion kits. You might check into those so you could single source all of your parts. https://www.leafbike.com/products/e...inch-48v-1500w-rear-hub-motor-wheel-1112.html

 

[reluctantsuburban]

Speed was not my top priority. I'm good with 20mph sustained (no commuting for me). For me it was more about an enthusiastic launch when crossing a busy street or something. Lotsa power, but nothing really sustainable. It was the only way I could make the stock Rad battery, which is wired with 14awg wire internally (good for 20 amps or so sustainable, or about 1000 watts, but much more for a short blast across a street for instance). The way I did that was to limit max wattage level to 1100 or so in setup.

Testing done originally, prior to setting up the max wattage and 20mph speed limit, had the bike accelerating enthusiastically up to about 35 mph before running out of room - and yes I'm a big guy (320lbs). I doubt 40 would be difficult. Yes, Big grin. Edit: motor was pulling a little over 1600 watts here!

40 mph still possible, but you would need to sturdy up the electrical - starting with a rewired battery at minimum. That 14awg would have to go in favor of something like 10awg. and then I'm not sure if the individual cells would stand up to a lot of abuse. The battery certainly wasn't speced out for it originally!

I ended up using a KT based (LCD3 display capable) 12 mosfet 35 amp max controller that features the ability to work with no Hall sensors in the motor (KISS logic). It's the smoothest and quietest of the 4 I've had on it. Why 4 is another story, not relevant here. You can pretty much order out your own kit, other than the motor, right here, at very good pricing.
http://www.pswpower.com/ven.php?cargo.2016-3f-28ym

I used a 1500 watt motor because it was only a couple bucks more than the 1000 watt. It also features wires that come out the side of the axle vs. the end, making them less vulnerable to my way of thinking. Leafbikes has a pretty good reputation, offering reasonably decent support (still Chinese/on the cryptic side), and maybe not the least expensive. My first 2 DIY bikes were built with his conversion kits. You might check into those so you could single source all of your parts. https://www.leafbike.com/products/e...inch-48v-1500w-rear-hub-motor-wheel-1112.html

Thanks so much for the links. I'm thinking I would want to stick to a top speed of ~30mph while pedaling hard, so I wonder if the 1000w would be sufficient for my needs. Although, with a decent controller, it would probably make sense to go for 1500W if they are similar in price and just set my speed on there manually to what is needed. I'll do a little more research on this tonight. Again, thanks!

 

[AHicks]

Just keep in mind when using the LCD3 display with a KT series controller, YOU have the final word in what the system is allowed to pull. No Bluetooth, no laptop required, everything is done right through the display. Limiting power can be a means of extending available range, or limiting power due to known weak components in the system. If you want a max of 30mph while peddling hard, you can take it up to that speed and see exactly what it's drawing. Wattage in use is displayed real time - just like mph. That in mind, you can go into setup and limit the power to the wattage you saw when doing 30 mph.

Personally, there would be some concern over the capabilities of the Rad battery with extended usage at 30mph. Up side is I don't think you would hurt it finding out, as it's protected by a 40 amp fuse. Seems like rad would be smart enough to install a fuse that would let go prior to allowing the battery to be damaged. Nothing saying the stock battery could not be replaced with something much heavier, maybe something in the 20ah category.

Cool part is with a little homework on the topic (or a lot!) many of these parts can be easily substituted to customize the bike pretty reasonably - especially when compared to what a production bike with similar power might cost.

There's also the potential this same system (LCD3 display/KT series controller, 1500w DD motor) could be used to convert a mountain bike of your choice. That REALLY opens up the list of possibilities! My biggest thing there would be to start with something that comes with disc brakes. After that, pretty much anything goes. The 29'er I built was a Schwinn Boundary I bought for 200 bucks at Walmart, and worked great! Not near as "cheap" as what I had heard. https://www.walmart.com/ip/29-Mens-Schwinn-Boundary-Dark-Green-and-Black/153585860

Last, regarding the 1500w vs. 1000w call, I don't know this for a fact, but doubt there is a lot of difference in the efficiency between them. If you're pulling 1000 watts with either, thinking the 1500 will be putting out pretty much the same torque as the 1000w would be. My thinking is the 1500 may not be working as hard/generating as much heat. Could be wrong there though. There is no doubt it will have reserve power not available in the 1000w. Have fun with all that info! -Al

 

[Mr. Coffee]

Okay, okay, I admit it, I might want a suspension on this ride (mayhem around 2:35):