Search found 3784 matches

by johnrobholmes
Apr 16 2015 4:26pm
Forum: E-Bike Technical
Topic: 19" Motorcycle Wheels vs 26" Bicycle Wheels (rim and tires)
Replies: 2124
Views: 308175

Re: 19" Motorcycle Wheels vs 26" Bicycle Wheels (rim and tir

I would recommend 13/14 or straight 13ga on the hope hubs. Also recommend 3 cross.
by johnrobholmes
Apr 04 2015 10:18am
Forum: E-Bike Technical
Topic: Removing screw on disc adapter
Replies: 11
Views: 1096

Re: Removing screw on disc adapter

either bolt in a lever arm, or lightly grab the adapter in a vice and turn the wheel against it.
by johnrobholmes
Apr 04 2015 10:16am
Forum: E-Bike Technical
Topic: 19" Motorcycle Wheels vs 26" Bicycle Wheels (rim and tires)
Replies: 2124
Views: 308175

Re: 19" Motorcycle Wheels vs 26" Bicycle Wheels (rim and tir

I would like to find some moto rims that suit 2 cross on big hubmotors without extra drilling. Strength+reliability should be at least as good if not better and 2 cross has a nice visual appeal to me. I haven't found a rim maker with good extrusions that can handle the larger angles. Either they sp...
by johnrobholmes
Apr 03 2015 12:02am
Forum: Motor Technology
Topic: Best 100v TO220 package FET made? It's cheap too. :-)
Replies: 64
Views: 9345

Re: Best 100v TO220 package FET made? It's cheap too. :-)

I've been trying to find the FET you posted luke, that was a fatty 3 phase all in one package with fantastic heat transfer and gate charactaristics. Still have that kicking around, or maybe there is another package now that is the jam? Just got into a position to design hardware with the software/ p...
by johnrobholmes
Mar 31 2015 10:46pm
Forum: Stand-up E-scooters and E-skateboards
Topic: Fast electric longboard – Dual hub motor
Replies: 49
Views: 24729

Re: Fast electric longboard – Dual hub motor

Do the ESCs always pop after going downhill or soon after you let off the throttle? The way you install the caps isn't the best, but I would hazard a guess that you are getting an inductive spike or regen that is surpassing the voltage rating of your ESC.
by johnrobholmes
Mar 26 2015 8:34am
Forum: Battery Technology
Topic: This is how A123 care about quality control
Replies: 262
Views: 25080

Re: This is how A123 care about quality control

The internet is 99% complainers that spend far more time fretting than learning from experience. Real life is the polar opposite it seems. This forum was a break from the norm for a very long time, but the ways of facebook and instant satisfaction have slowly crept in. I would suggest you wait for t...
by johnrobholmes
Mar 26 2015 8:24am
Forum: E-Bike Technical
Topic: 19" Motorcycle Wheels vs 26" Bicycle Wheels (rim and tires)
Replies: 2124
Views: 308175

Re: 19" Motorcycle Wheels vs 26" Bicycle Wheels (rim and tir

inbound VS outbound VS alternating isn't very important when the flanges are far enough apart for proper bracing, like a cromotor. What is important, is making sure the spoke angles are good for the rim. On rims where we could get away with outbound spokes, we would alternate the pattern. On rims wh...
by johnrobholmes
Mar 25 2015 9:17pm
Forum: E-Bike Technical
Topic: Motocross fork or DH fork for heavy rider w/heavy bike?
Replies: 45
Views: 5727

Re: What motocross fork might fit 1.1/8" steerer tube?

Best bet on the rear for hard riders is a 17 to 19" moped rim and spokes suitable for the hub flange, generally 13 or 12 for aluminum and 11 through 9 for steel. Unless you need rim brakes, then you are pretty much SOL.
by johnrobholmes
Mar 17 2015 9:52pm
Forum: E-Bike Technical
Topic: Motocross fork or DH fork for heavy rider w/heavy bike?
Replies: 45
Views: 5727

Re: What motocross fork might fit 1.1/8" steerer tube?

Here is what all they guys building 45 to 60mph bikes get from us- regular 36h downhill hub of some sort, dmr revolver is popular for the price 13g spokes with matching nipples for a moto rim, 3 cross lacing 19" moped weight rim, I now carry the MMP front 19" that is matched for front MTB hubs and l...
by johnrobholmes
Feb 22 2015 9:32pm
Forum: Large EV General Discussion
Topic: I got a Corbin Sparrow! A very modded Corbin Sparrow
Replies: 52
Views: 8607

Re: I got a Corbin Sparrow! A very modded Corbin Sparrow

The RPM limit is likely bouncing the gates between regen and torque currents, which would have a mean effect on brushes. If you want to tinker, reducing the brush width from the leading edge could help although I hate the suggestion of reducing brush area. You could also serrate the brush face to re...
by johnrobholmes
Feb 06 2015 10:28pm
Forum: E-Bike Technical
Topic: 9C Hub motor wires side / direction
Replies: 20
Views: 4517

Re: Strangest noise ever heard on a 9C hub

probably a bad combination of phase or hall, I don't have speakers to hear if it is grumbly. The strangest noise I ever heard on my 9c was when I almost plowed into a big deer at dusk. Being on a dead silent electric bike I took him by surprise. I heard him huff and snuff when I scared him, and came...
by johnrobholmes
Feb 03 2015 11:19pm
Forum: General Discussion
Topic: Tesla P85D Insane Mode
Replies: 120
Views: 13187

Re: Tesla P85D Insane Mode

When you start needing 400hp just to carry around your personal deficiencies, you need help, not appeasement. If most Americans are sick, that doesn't mean it isn't sickness. You guys seem to think this stuff is victimless. I'll take all these "victims" suffering at the hands of driving this vehicl...
by johnrobholmes
Feb 01 2015 4:59pm
Forum: General Discussion
Topic: Tesla P85D Insane Mode
Replies: 120
Views: 13187

Re: Tesla P85D Insane Mode

The one thing I keep seeing when people compare the model S to other cars, they tend to compare two door sports cars to the S which is nothing more than a family sedan that happens to have some power. Sure you can get overall better performance with a 918 (with $730,000 more cost) or a 911, but it's...
by johnrobholmes
Jan 31 2015 12:56pm
Forum: General Discussion
Topic: Tesla P85D Insane Mode
Replies: 120
Views: 13187

Re: Tesla P85D Insane Mode

I test drove a p85 a few weeks back, and I kept hitting my head on the rest :lol: Phenomenal car for a family sedan. It drove easily at low speed and power, vision was great, driving was comfortable. now I am hell bent at paying off the house quickly so I can purchase one, so far I've saved $600 abs...
by johnrobholmes
Jan 17 2015 2:42am
Forum: Motor Technology
Topic: Motor lifetime
Replies: 26
Views: 3527

Re: Motor lifetime

Other than bearings wearing/ failing over time, a brushless motor doesn't have a defined life when run within a reasonable thermal envelope. Buy what you want, run it, keep it dry and/or lube the bearings every now and then to make sure water isn't sitting in them. Decades of reliable service unless...
by johnrobholmes
Jan 16 2015 6:27pm
Forum: Battery Technology
Topic: The Cycle Satiator, universal charger for the enthusiasts
Replies: 744
Views: 131805

Re: The Cycle Satiator, universal charger for the enthusiast

I could use a 72v version for my 24s LiFe scooters as well, it would be nice to hard mount the charger on there and stop lugging around the brick of a king charger I'm always afraid is going to fail or catch fire. I've had so many of those things poop out with no warning, it feels like a gamble ever...
by johnrobholmes
Jan 11 2015 8:19pm
Forum: E-Bike Technical
Topic: The wheel-building spoke-lacing thread, post your tips
Replies: 242
Views: 44821

Re: The wheel-building spoke-lacing thread, post your tips

Mauimart- use one cross. 12g will be too thick for the rim. Ideally you would redrill the hub flange with smaller holes for 13/14 butted spokes that are also closer together to reduce the angle. Otherwise you will need to use washers.
by johnrobholmes
Jan 11 2015 5:20pm
Forum: E-Bike General Discussion
Topic: Trashed another rim.
Replies: 23
Views: 1984

Re: Trashed another rim.

I bet you could fit a 19 in it with a 2.0 or 2.25" tire. What spoke gauge are you running? If its 13, you will get better bicycle rim life by redrilling your spoke holes closer together and using 13/14 butted spokes.
by johnrobholmes
Jan 11 2015 5:04pm
Forum: General Discussion
Topic: Laser Gun Project
Replies: 66
Views: 8185

Re: Laser Gun Project

I've bought from DTR as well, great vendor. The cheap ebay CCCV regulators don't do a good job of regulating current on startup though, they will toast a laser over time. You can visibly see the brighter flicker when it powers on, especially when the driver is turned down to 50% of rated output. I s...
by johnrobholmes
Jan 11 2015 12:17pm
Forum: E-Bike Technical
Topic: Science, Physics, Math, & Myth
Replies: 626
Views: 62427

Re: Science, Physics, Math, & Myth

John, you of all people shouldn't brush off the complexity of a motor controller. The lower end of dumb and semi dumb controllers will be raised over time as hardware technology trickles down and new softwares become old, but prices aren't artificially high because of a group of greedy vendors. The ...
by johnrobholmes
Dec 29 2014 11:39pm
Forum: E-Bike General Discussion
Topic: Magnesium rims for ebikes
Replies: 41
Views: 3655

Re: Magnesium rims for ebikes

Although rim brakes are great and all, anything above a 30mph or 60lb ebike I do use disc brakes too.


I drilled a rim at angles once. Marginally better. What actually solves the angle problem is to redrill the holes in the hub flange closer together for a 82 degree spoke insertion into the rim.
by johnrobholmes
Dec 27 2014 11:29am
Forum: E-Bike General Discussion
Topic: Magnesium rims for ebikes
Replies: 41
Views: 3655

Re: Magnesium rims for ebikes

Chalo is the same guy that argues with me that rim brakes are just as good for a E bike as disc s And Chalo is correct about this in many ways. Even with rubber based compounds the leverage and brake surface area favors rim brakes. If you don't believe Chalo, then ask a trials rider why they use ri...
by johnrobholmes
Dec 27 2014 12:37am
Forum: E-Bike General Discussion
Topic: Magnesium rims for ebikes
Replies: 41
Views: 3655

Re: Magnesium rims for ebikes

As it has been stated, choosing a quality spoke properly sized for the rim stiffness is key to a long lasting wheel. over the years I have learned that trike wheels are quite special in regards to their needs, and that going thinner or thicker doesn't always address the root issue of why spokes are ...
by johnrobholmes
Dec 21 2014 11:13pm
Forum: Alternative Energy
Topic: new version of dual vertical axis turbine
Replies: 4
Views: 1282

Re: new version of dual vertical axis turbine

contra rotating turbines, I hear it is great for efficiency. Looks like a pretty nice compact unit!


I will be flying down to DFW for a business meeting in the next few weeks, where are you located?
by johnrobholmes
Dec 20 2014 11:34am
Forum: E-Bike Technical
Topic: 19" Motorcycle Wheels vs 26" Bicycle Wheels (rim and tires)
Replies: 2124
Views: 308175

Re: 19" Motorcycle Wheels vs 26" Bicycle Wheels (rim and tir

moto rims are measured by the internal width of bead seat. Bicycle rims are measured by the external width.