grandmasterE
10 W
- Joined
- May 25, 2009
- Messages
- 66
Any updates?
Yeah! My motors and controllers finally came in today. What a wait.grandmasterE said:Any updates?
Yikes. I hope my frame holds up better. I have just under 1,800 miles on it and no cracking yet. Thanks for the heads up on this problem.Qwiksand said:I hope you have better luck with your frame than I did, they're notorious for this:
Documented here: http://endless-sphere.com/forums/viewtopic.php?f=6&t=14788
dogman said:longer seatpost would tend to reinforce that area. It looks to me like where the seatpost ends inside the tube. If further down, a second, cut off section of seatpost could reinforce the area from inside some.
TylerDurden said:On retrospect, an internal post may not resolve the cracking. That is not a torque fracture. It appears to be pulling the bracket right out of the tube.
Qwiksand said:TylerDurden said:On retrospect, an internal post may not resolve the cracking. That is not a torque fracture. It appears to be pulling the bracket right out of the tube.
I think you're on the mark here, TD. The crack is at a high-stress point just below the seat tube shock mount, a good 12" below where the seatpost ends.
It seems that most of these failures happen on large (20") frames with riders in the over 200# category, so even fully built with a crap-ton of batts, GK should still be under that weight load. With camelback and gear, I weigh in around 210-215- I put alot of miles on this frame at that weight with rear shock pressure set around 110-120 psi. I think my increasing the rear shock psi to 160 coupled with the increased weight on both sides of the shock assembly fulcrum (heavier rear wheel and heavier triangle/rider) caused my failure.
Russell said:Very cool
So those are the largest and most powerful (48V/500W) versions of the Cute motors bmsbattery/ecitypower offer right? Any idea how fast they are supposed to spin at 48V?
-R
GrayKard said:Is it possible that the rear suspension also bottomed out at some point causing a huge spike in the pressure on that area? Or did the higher air pressure you put in the shock prevent that?
The fact that you put a lot of miles at a bit over 200 pounds with no problem does encourage me as even with my batteries and my usual gear I will be at about 170 pounds. The bike should come it at about 45 as I dumped the rear rack which was nothing but a headache.
Gary
GrayKard said:The test fitting of the motors looks good. Here's the front motor in:
View attachment 2
Had to remove the paint inside the dropouts for it to slip in. I will also have to file a little to get the curve to match the axle and go all the way down.
Width was a perfect except the inside washers aren't on yet. I will have to spread the dropouts to get those in. I will be adding torque arms once the fit is right.
Now the rear motor:
View attachment 1
This one dropped in without any tweaking. Yes that's an 8 speed freewheel in there. It will have the same spacing as the freehub once the washers are on. Same as the front the width was right on without washers. Very little spreading will be necessary to make it work.
I will need to radius the drop out to get it seat all the way but it's a much better fit than the front so won't need much persuasion. Torque arms here too.
Brake rotor fit is not bad. The front appears to line up but the rear will need some work. I will need to take off a bit of material from the rear bracket to move it out of the path of the rotor. But overall a pretty darn good fit.
The thing I was worried about the most, gearing, was no problem at all. But the dropout shape I thought looked to be easy will actually take a lot of precise filing to get the snug fit it needs. I'm a perfectionist with details like that though so it will get done right, just will take some time.
I also finally decided on and ordered batteries.
Two shrink tube 48 volt 12 amp hour packs from BMSbattery. Was more expensive than the bike due to the $156.00 shipping charge.
Mark_A_W said:And I fear you will encounter severe wheel-dish issues with such a big cassette, and the motor is not well designed for a big cassette - the spoke rim is far away from the edge of the motor.
Mark_A_W said:Don't spread your dropouts for those washers, file the washers down.
And I fear you will encounter severe wheel-dish issues with such a big cassette, and the motor is not well designed for a big cassette - the spoke rim is far away from the edge of the motor.
GrayKard said:Mark_A_W said:Don't spread your dropouts for those washers, file the washers down.
And I fear you will encounter severe wheel-dish issues with such a big cassette, and the motor is not well designed for a big cassette - the spoke rim is far away from the edge of the motor.
Well, the motor sits in the same place regardless of which freewheel is on it. The position is determined by the axle. I have not added any spacers to fit the 8 speed as opposed to a 6 speed so the dishing will be the same regardless.
What I need to do is measure the width and position of my current non motor hub and cassette and check that against the motor and freewheel setup. I suspect that they will be very similar as there is already some dishing on my non motor rim both front and rear.
The current dishing on the rear is due to the freehub, and the front is due to the disc brake rotor.
As to filing the washers: They are going to spread the dropouts regardless of their width as without them it's a perfect fit. But they have to be there as the shoulder on the axle is way too small to be the surface that contacts the dropouts.
One option would be to shave down the shoulder on the axle. But to do it right I would have to pull the axle and put it in a metal lathe I have access too. I'm not too thrilled about doing that though.
Another option I have considered it so machine a space inside the dropouts for the washer and then JB weld them in place and cut them so they are C washers. Not so happy with that option either.
Any suggestions regarding either issue are very welcome.
Gary