Starting my DD Hub motor project. Its been nice to have the help from the forum members here to give me the confidence to press on with the project. I will post my progress and my questions for help as I go.
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……..Components shown in foreground are the makings of an electric DH mountain bike that I hope to put together in the next while. The motor is a Crystalyte HS3540 DD hub motor with 2 x 48volt 10ah Lithium Manganese batteries, 35A Infineon Controller, Grin Cycle Analyst and steel Drop outs that act as a kind of torque arm to help with axle twist in this area.
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…………2004 Giant Team DH bike that will be the platform for this project. It is now sporting 26 inch wheels front and rear but the rear Direct Drive Hub motor I will use is laced to a 24 inch rim. I have gone with the 24 inch rear wheel to get more torque, and help with range and overheating issues for climbing hills.
Last edited by waynebergman on May 08, 2013 3:13 pm, edited 6 times in total.
That's very cool, the Giant DH is my choice for a full suspension ebike. All the suspension is low and out of the main triangle, it's a really nice design. wish you all the best, it's fun building and doing it right. "doctorbass" uses a Giant DH for one of his E-megabike test vehicles, I think he's up to around 70mph!
Duct taping things in place to get a feel for what may go where. I will fasten things in place with 6061 Aluminum sheet and tubing once I get a good feel for the best layout. I was kind of hoping the battery packs would fit in the front triangle but not these ones in there stock enclosures. If you open them up the warranty is void and not sure the internals of both packs could be rearranged to fit into a custom made unit to fit into the front triangle. Maybe down the road this could be a fun improvement.
The one battery pack shown on the underside of the down tube will go in that position to start with for sure. The second pack behind the seat tube and down tube I am not so sure about. One issue is the travel of the rear triangle may have the tire bumping the battery pack even though I will be going with a 24inch rear wheel and also the weight is a bit high for my liking. I may just mount it on the top side of the top tube. One thing about the seat tube mount is it will be easy to do. The square tubing shown in picture around my seat tube would be easy to weld to for fastening battery to and the weight could be suspended by attaching the top part of battery casing to the saddle rails. All free from the bike frame.
Any giant owners out there know how close the rear tire comes to the seat tube when the rear end is fully compressed? I am hoping that my 24inch tire will help a bit and I am sure I will never bottom this bike out with my weight and riding style but it would be good to know how close the tire gets to the seat tube in a worst case senerio.
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Starting to work on the unit to hold my rear battery pack. The extruded piece shown in the first photo will be drilled out to 27mm to slip over the seat post and be cut and welded to the fabricated piece shown in the second picture. My thinking on this is I will support the weight of the battery mostly from this seat post assembly and have some kind of shock absorbing foam on this unit to help with the off road abuse it should see. I am still not sure if the swing arm assembly and its 24" wheel and tire configuration will hit the battery in this mounted position in full compression but we will see. If this position for the battery turns out to be no good, I will mount this second pack on top of top tube but I would rather not.
Last edited by waynebergman on Nov 23, 2011 11:08 am, edited 1 time in total.
Be interesting to see how the battery holder turns out. Really good idea for a bike with an extended swingarm. Looks like you have the skills to make a steel swingarm a few inches longer. Then you could carry along the seat tube with no problems. Maybe a project for later? Allows the really crazy strong pinch dropouts too.
Make it support itself as much as possible on the frame. I've bent more than one seat tube, and broken one.
I think the seat post unit to hold the rear battery will look like so. I did not have a 27mm drill bit or anything close enough to resize the extruded piece shown earlier so went with the plan B shown here with square tubing and rubber grommet. I plan to use a combination of velcro and rubber straps to further secure this unit to the frame and also the same to fasten the battery to the holder. The batteries weight is mainly supported by the seat post and I plan to also epoxy the square tubing to the bike seat post to stop it from moving from side to side. I am pretty sure with the smaller rear wheel I will not be bottoming out the back tire under travel compression into the battery compartment. I have 8.25 inches of rear travel and figure I will never use it all as I am light in weight, also the axle will sit a bit lower than stock if I go with the custom drop outs made by KIWI. The combination of lighter rider weight, dropped axle position and smaller tire will all be in my favor for letting me put this battery in this position so close to wheel travel limits...........I hope.
Looks good Wayne. If I may make a suggestion.... Make sure you like the seat height, I tend to run my ebikes seat height at least an inch or two lower than my cross country bike because pedal efficiency is not as important being able to lift my weight off the saddle and maneuver like a DH bike. Your seat might be right where you need it, I am just suggesting you leave an inch to adjust it down in your battery setup. Also, if you want that extruded piece bored out to the right size I could probably do it for the cost of a 6 pack and shipping. The guys I work with will do it cheap and I can have it back to you in a week. Your setup doesn't look bad, but that extruded piece would be real clean and pro looking.
Four wheels moves the body, Two wheels moves the soul
Thanks to Justin @ http://www.ebike.ca He brings the soul to ES
Thanks etard.................good point on the seat height. I could just cut down the height of the sqaure tubing to give me about 3 inches of drop on the saddle for steeper downhills and forget about the internal epoxy treatment. Thanks for the kind offer on the drill out. At this point I will just see how the test ride goes when all is together. I agree with you the extruded piece would look better but who knows I may opt for taking the LithMang packs apart and tucking everything into the main triangle should I like the bike enough and want the very best of placement for my battery weight.
My Controller holder shown here. I cut length wise in half a piece of Aluminum round tubing and attached it to a piece of flat Aluminum with some rivets. Then this unit was attached to controller with machine screws and then zip tied to top tube with rubber spacers for extra holding power. So far things are looking like I will be able to get away with out altering the frame with my efforts to attach this controller, and the one seat post mount battery, but I am not so sure about the lower battery that will hang from and under the down tube. I may want to plant a few stainless rivets to hold the Aluminum unit I will make to hold this lower battery. If I drill some 3/16" holes to allow for my rivets ( say three in total about 4 inches apart )in the down tube will I be weakening the frame in a way that would be a concern? I am thinking not, but thought I should check with those that may know for sure?......thanks
Thanks for the advise on the saddle height. I have now chopped off some of the square tubing that fits around the seat post to allow for a bigger drop in saddle height when needed. Also at the bottom of this battery holding unit I have added a one inch piece of square tubing that fits into the rear shock frame mount. This tubing is attached to the frame with 1/4" machine screws to stop the battery holder from moving side to side and also to stop it from spinning out of square from the frame.
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Last edited by waynebergman on Dec 02, 2011 10:57 pm, edited 1 time in total.
This is the start of the lower battery holder. I want to have this unit pivoting from the bottom bracket area so it will drop down for battery removal and installation. I will make use of the tabs already on the frame that secures the rear shock linkage assembly. I will shop for a new bolt that is 1/2" longer than the bolt that is being used now to secure the pivot on this linkage. The extra length of this new bolt will let me pivot this battery mount assembly to this linkage area. It should stop the battery holding unit from wiggling around once secured and also let the whole assembly drop down out of the way of the forks and wheel for removing the battery. Pictures to follow as things progress. Kind of designing this one as I go but feeling good about keeping this battery weight down low where it belongs.
Lower battery pack holder shown under the down tube in the basic position it will be fastened to the bike to. The two smaller assemblies shown next to the battery will be riveted to the main battery holder assembly to help secure the battery in its place. I will pad with foam or rubber all contact points between the battery case and the frame and also the inside the battery holder that I am making here.
Are you going to run the 135mm dropouts from Kiwi also? I've got an 03 DH Comp that I'm doing regular maintenance on now to get it up to snuff for the speed it's going to be doing. Can't wait to get the dropouts!
Making some good headway now on the holding units for my batteries. Pretty much done. Just a few bits of velcro and rubber and what not to finish things off. I am happy with the lower placement of the second battery pack as far as function goes. However I am not real pleased with how it looks, but for right now its going to do the trick.
Crusoe..........to answer your question yes I plan to go with Kiwi's drop outs when they are ready. I have a set of Doctorbass drop outs and they are awesome. I am only wanting to go with the units from Kiwi as I don't know if I want to alter the frame with chopping the rear drop outs to make the Dr Bass units happen plus the Kiwi units look Awesome too. After riding this bike I realize its a great bike and I just can't picture myself cutting into this frame for this part of the build. Not sure if I am just chicken or if its out of respect for the person that made the frame. The more I look at this frame I feel it is a piece of metal art, Giant has done there homework on the design and building of this frame for sure. I will keep the Doctor Bass units in case I build a frame from scratch one day.