seeking ultimate ebike build advice Specialized DH

[usa_electrophile]

I recently got a deal on a used (very well taken care of) Specialized Demo Pro 8 Downhill Bike with titanium spring upgrades

I also have a 9C hub motor I recently bought off here

I'd like a setup that compliments the bike, doesnt impair it, would like at least 45 mph on flat ground and range of 10 - 20 miles would be fine

I'd like to be able to do small jumps and air with the bike (as it was designed), any advice on a configuration and choice ?

any used items for sale to help get it done?

http://www.mtbr.com/cat/bikes/downhill-full-suspension/specialized/demo-8-pro/prd_364828_1542crx.aspx

the suspension on this thing is phenomenal, i think this will be an ultimate lightweight off/on road motocycle when im done with it

 

[dogman dan]

9c hubs of the typical 2807 winding tolerate 40 mph running for about 10 miles before they are about to melt, and when pushed to 45 mph they melt sooner.

So good choice of bike, but not the motor for 20 miles at that speed.

And for 20 miles at 45 mph, you gonna have a lot of battery to strap on. (doesn't impair it? :lol: )

Get started with 72v 10 ah of lico (RC lipo), and at least get the 10 mile range at 35-40 mph. Then when you see for yourself what will be needed for more, you can decide if you want to really up the ante or not.

 

[MadRhino]

I love the Demo 8, one of my favorite bikes of all time.
Mine have seen many motors, currently fitted with the Cromotor, pulling 150a batt. current out of 24s Lipo.

 

[dogman dan]

That's where you are headed all right, Cromotor. Mad Rhino is your guru. But have fun melting that 9c meanwhile. When you build your torque plates, build for the 5000w you'll be running as soon as you can afford it.

 

[parajared]

I highly recommend a temp sensor. They will save you money down the road. Rc on-board sensors are nice, like the traxxas on-board or TG3. I use TG3 and love it.

Also, I should point out that I have observed that hubs tend to overheat on high voltage on anything low speed and technical. I have had best luck commuting on 72 volt, (35mph) and trail riding 48v (25mph).

Mad Rhino seems to love his 24s setup (45mph on 9c). I'm not sure how he does it because I have observed nothing but massive heat generation on 24s on my 9c.

 

[usa_electrophile]

thanks for the advice

I think 9c will still serve a purpose such as for my wifes bike or if i can convince myself 35mph is fast enough

Also 10 - 15 mile range would be fine too, i'd rather have shorter range and spend more on motor and less weight and let batteries evolve and price drop a little more


how about this ?

http://www.hi-powercycles.com/product.sc?productId=48&categoryId=4

 

[usa_electrophile]

i'd love a Cromotor but there doesnt seem to be any available

i'd take one now for a reasonable price if there was one available and they clearly ruled over the Crystalyte and HPC offerings (augmented Crystalyte?)

 

[MadRhino]

I have the big 5404 Clyte on my V 10. It is not as fast as the Cromotor, but it is a much better trail climber because its size and weight make it capable of shedding heat better, and it is not as hard on controllers. Lots of work to properly tune a suspension with a 33 pound hub though.

 

[usa_electrophile]

I read that the Brammo empulse has water cooling.

Also of course PC overclockers have used water cooling for years.

Has anyone yet worked out a good way to water cool these ?