pianoman
10 mW
- Joined
- May 29, 2011
- Messages
- 29
Hi everyone,
I'm upgrading my bike almost completely, new frame, fork, wheels, etc., very few things will remain from the previous bike which was a standard xc hardtail 9c 9x7 rear, 48v 30a controller, 14ah sla, front suspension.
Now it is going to be a higher power setup:
5304 rear motor
lyen 72v 18 fet controller
a123 24s5p (about 79v) from cell_man
CA
atomlab pimp 2 frame
rockshox domain u-turn 115m-160mm fork, 20mm thru axle, 35mm steel stanchions
bmx handlebars for upright riding position
somewhat ugly, but very comfortable seat, long seatpost
atomlab pimp 26 inch rims
Maxxis hookworms, dh tubes and slime
Avid Bb7 203mm on front and bb5 160mm rear mechanical disk brakes
I’ll have a custom made long and strong seatpost to ride at normal height, batts will fit in and some over the triangle. I like to pedal at all times, that way it still feels like a bicycle while doing some light workout as well (even if it doesn’t help much to 5304, ha, ha…), so I'll put a 65tooth chainring (from http://www.raptobike.nl), rear is 7speed 11-32tooth, to be able to pedal at 60-70kmh. I'm planning to program the controller at 60 amps, that would make the top power of 4800w aprox. I decided for a hardtail because of lower cost, more room for batts, simplicity and because I ride almost only on smooth pavement. I guess this frame is much stronger then the one on previous bike that was a low price 6061 aluminium xc hardtail. Atomlab DJ frame is cromoly, but I'll make torque plates anyway for safety and they'll keep the wheel in if the nuts go loose. I bought this frame for being cromoly, strong with horizontal 5mm thick dropouts, I know it’s probably not ideal frame for ebike at high speeds because of a somewhat shorter wheelbase, also it has a smaller triangle to fit batts, I'll have to put some over the top tube too and then hide it all with custom side covers. But this was the best and strongest economically viable frame option I could find were I live.
What I’m trying to figure out is if I can run my travel adjustable fork at full 160mm, or that’s too much stress on the headtube. Headtube is reinforced, but only on the downside, frame is build for 80-100mm fork, but atomlab.com and most sellers say longer forks can be used for mtb style geometry, but doesn’t specify how much longer, on one sellers site I found that for freeride etc. 100-130mm fork is suggested for this frame, so maybe 120-130mm would be ok, but can it be more? I hasn’t been able to find any more info online about this, just in general it seems that very long forks are not recommended for hardtails (well perhaps it’s really unnecessary for non powered riding other than DH or freeride anyway, and for those FS is standard). The only reason I would like to run it long is just for slacker angle and slower steering, that I guess is better for high speeds. I’ll ride almost exclusively on smooth pavement, no potholes. If offroad, I can always lower the fork if the trail is too bumpy.
What max travel of the fork would you suggest? I see DJ frames are not that common for ebikes, well something like greyborg would have been ideal, but shipping to Chile where I live would be expensive, customs etc., and the frame itself is much more expensive, eventhough a very good quality and FS.
Has anyone tried DJ ebike with longer fork at high speeds, is it stable? My bike is still not assembled, because I don’t have all parts yet. When I’ll have the bike completed, I guess I’ll find out experimenting about the difference between running it at 120mm or 160mm, if those 40mm extra are a significant improvement in handling, or really not much or even the opposite. I just wouldn’t want the frame to fail, especially not at 72v speeds.
Here’s the link to my frame
http://www.atomlab.com/mtbframep2.html
Your opinion is highly welcome, best regards.
I'm upgrading my bike almost completely, new frame, fork, wheels, etc., very few things will remain from the previous bike which was a standard xc hardtail 9c 9x7 rear, 48v 30a controller, 14ah sla, front suspension.
Now it is going to be a higher power setup:
5304 rear motor
lyen 72v 18 fet controller
a123 24s5p (about 79v) from cell_man
CA
atomlab pimp 2 frame
rockshox domain u-turn 115m-160mm fork, 20mm thru axle, 35mm steel stanchions
bmx handlebars for upright riding position
somewhat ugly, but very comfortable seat, long seatpost
atomlab pimp 26 inch rims
Maxxis hookworms, dh tubes and slime
Avid Bb7 203mm on front and bb5 160mm rear mechanical disk brakes
I’ll have a custom made long and strong seatpost to ride at normal height, batts will fit in and some over the triangle. I like to pedal at all times, that way it still feels like a bicycle while doing some light workout as well (even if it doesn’t help much to 5304, ha, ha…), so I'll put a 65tooth chainring (from http://www.raptobike.nl), rear is 7speed 11-32tooth, to be able to pedal at 60-70kmh. I'm planning to program the controller at 60 amps, that would make the top power of 4800w aprox. I decided for a hardtail because of lower cost, more room for batts, simplicity and because I ride almost only on smooth pavement. I guess this frame is much stronger then the one on previous bike that was a low price 6061 aluminium xc hardtail. Atomlab DJ frame is cromoly, but I'll make torque plates anyway for safety and they'll keep the wheel in if the nuts go loose. I bought this frame for being cromoly, strong with horizontal 5mm thick dropouts, I know it’s probably not ideal frame for ebike at high speeds because of a somewhat shorter wheelbase, also it has a smaller triangle to fit batts, I'll have to put some over the top tube too and then hide it all with custom side covers. But this was the best and strongest economically viable frame option I could find were I live.
What I’m trying to figure out is if I can run my travel adjustable fork at full 160mm, or that’s too much stress on the headtube. Headtube is reinforced, but only on the downside, frame is build for 80-100mm fork, but atomlab.com and most sellers say longer forks can be used for mtb style geometry, but doesn’t specify how much longer, on one sellers site I found that for freeride etc. 100-130mm fork is suggested for this frame, so maybe 120-130mm would be ok, but can it be more? I hasn’t been able to find any more info online about this, just in general it seems that very long forks are not recommended for hardtails (well perhaps it’s really unnecessary for non powered riding other than DH or freeride anyway, and for those FS is standard). The only reason I would like to run it long is just for slacker angle and slower steering, that I guess is better for high speeds. I’ll ride almost exclusively on smooth pavement, no potholes. If offroad, I can always lower the fork if the trail is too bumpy.
What max travel of the fork would you suggest? I see DJ frames are not that common for ebikes, well something like greyborg would have been ideal, but shipping to Chile where I live would be expensive, customs etc., and the frame itself is much more expensive, eventhough a very good quality and FS.
Has anyone tried DJ ebike with longer fork at high speeds, is it stable? My bike is still not assembled, because I don’t have all parts yet. When I’ll have the bike completed, I guess I’ll find out experimenting about the difference between running it at 120mm or 160mm, if those 40mm extra are a significant improvement in handling, or really not much or even the opposite. I just wouldn’t want the frame to fail, especially not at 72v speeds.
Here’s the link to my frame
http://www.atomlab.com/mtbframep2.html
Your opinion is highly welcome, best regards.