Search found 13859 matches

by liveforphysics
Jan 19, 2018 4:18 am
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 90
Views: 1088

Re: Potential Catastrophic Frame Failer Averted ….sort of.

Cyclo cross had gained a lot in popularity here, since I quit about 10 years ago. It is a very tough disciplin. Courses are designed to push participants to their limits of strength and aerobics. I was too old to be competitive, but had a lot of fun trying. I was riding a Specialized Tri-Cross Expe...
by liveforphysics
Jan 19, 2018 4:14 am
Forum: E-Bike Non-hub Motor Drives
Topic: Design a Freewheel Crankset for Direct Mount Crankests
Replies: 24
Views: 820

Re: Design a Freewheel Crankset for Direct Mount Crankests

So funny just after reading this, I saw this: https://www.bikemag.com/gear/components/drivetrain/sram-introduces-dub-crank-bottom-bracket-technology/ Going to 28.99mm from 30mm, because you know... lol I do not see Shimano changing , except for perhaps keeping the 24mm ID , Outer Bearing and just ma...
by liveforphysics
Jan 18, 2018 6:55 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 90
Views: 1088

Re: Potential Catastrophic Frame Failer Averted ….sort of.

Everyone has a different kind of riding preference. Even on my road bike, I look for the biggest sets of stairs to drop or climb, and ride over log piles and aggressive downhill trails, and it still feels like inadquate training for cyclocross racing. Would you agree that you are an outlier on the ...
by liveforphysics
Jan 18, 2018 4:50 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 90
Views: 1088

Re: Potential Catastrophic Frame Failer Averted ….sort of.

My bike is 18.5lbs fully assembled with cyclocross tires. I don't know the bare frame weight.
by liveforphysics
Jan 18, 2018 4:23 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 90
Views: 1088

Re: Potential Catastrophic Frame Failer Averted ….sort of.

Even on my road bike, I look for the biggest sets of stairs to drop or climb, and ride over log piles and aggressive downhill trails, and it still feels like inadquate training for cyclocross racing. For that reason my roadbike is cromoly, and the frame has not yet broken (though I go through wheel...
by liveforphysics
Jan 18, 2018 3:28 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 90
Views: 1088

Re: Potential Catastrophic Frame Failer Averted ….sort of.

I've personally never felt like pedaling related forces were significant compared to riding impact related forces. Right. Potholes and even little bumps can have much higher instantaneous peaks (even if the durations are short), Still missing the point. You don't generally ride from one pothole to ...
by liveforphysics
Jan 18, 2018 7:01 am
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 90
Views: 1088

Re: Potential Catastrophic Frame Failer Averted ….sort of.

I agree with all of that and it matches my own experiences in working with aluminum. When Aluminum framed bikes were a few grand to buy, they might have budgeted in some/all of the process control and QC needed to weld them right. When aluminum framed bikes started retailing at walmarts for $249, I ...
by liveforphysics
Jan 18, 2018 5:35 am
Forum: General Discussion
Topic: Alternative current
Replies: 29
Views: 267

Re: Alternative current

Thank goodness Amberwolf was on this thread. Balancing channels stopped mattering after the days of tubes and output transformers. The right side of that modern chip amps has no idea if the left side is on the same planet with it or not, let alone if it's connected to a speaker. Your popping sound i...
by liveforphysics
Jan 18, 2018 5:19 am
Forum: E-Bike General Discussion
Topic: The winner is . Not what you think
Replies: 18
Views: 460

Re: The winner is . Not what you think

The irony is, my poorest friends all only have gas cars and drive lots of miles a year. My richest friends cars stay mostly parked and ride bicycles and ebikes.

Today super rich people still ride horses, though mostly for recreational purposes.
by liveforphysics
Jan 18, 2018 4:59 am
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 90
Views: 1088

Re: Potential Catastrophic Frame Failer Averted ….sort of.

I've personally never felt like pedaling related forces were significant compared to riding impact related forces. I've met e-beach, and something tells me his frame didn't crack from pedaling (no offense to e-beach who is a nice guy). Reynolds 953 was my favorite steel on paper for a while due to b...
by liveforphysics
Jan 17, 2018 10:09 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 90
Views: 1088

Re: Potential Catastrophic Frame Failer Averted ….sort of.

@LPF, Thanks for the welding offer, but getting up to SC from LA is a bit messy at the moment with the 101 closed, horrific mud slides and all. However the urethane casting tape sounds fun. I mean, if this frame is going to be put to pasture, a cheap fix for the purpose of having a peddle bike for ...
by liveforphysics
Jan 17, 2018 9:34 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 90
Views: 1088

Re: Potential Catastrophic Frame Failer Averted ….sort of.

It would only be useful if all joints were designed around being adhesive bonded joints, then it would be fine. For something like fixing a head tube, it would just fail, as the aluminum failed with that loading and the metal that cracked was bonded as well to itself as you're going to get from tha...
by liveforphysics
Jan 17, 2018 6:02 am
Forum: E-Bike General Discussion
Topic: Challenge with brakes
Replies: 5
Views: 125

Re: Challenge with brakes

Brakes on only front is how the last half dozen bikes I made were done, but on very lose sandy downhill trails a rear brake occasionally is useful. If she has a good performing front brake, adding any quality/amount of rear brake won't change her ultimate stopping times any, as a ultimate braking ef...
by liveforphysics
Jan 17, 2018 5:58 am
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 90
Views: 1088

Re: Potential Catastrophic Frame Failer Averted ….sort of.

It would only be useful if all joints were designed around being adhesive bonded joints, then it would be fine. For something like fixing a head tube, it would just fail, as the aluminum failed with that loading and the metal that cracked was bonded as well to itself as you're going to get from that...
by liveforphysics
Jan 16, 2018 10:47 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 90
Views: 1088

Re: Potential Catastrophic Frame Failer Averted ….sort of.

Broken bone casting tape is amazing stuff. A friend of mine, Craig Calfee has built many fantastic and robust bike frames using it with great success.

You're right it would be helped from UV decay through an outer paint layer. I would trust it more than I trust welds in aluminum.
by liveforphysics
Jan 16, 2018 9:46 pm
Forum: E-Bike General Discussion
Topic: Potential Catastrophic Frame Failer Averted ….sort of.
Replies: 90
Views: 1088

Re: Potential Catastrophic Frame Failer Averted ….sort of.

I could weld your frame easily for free, but welding aluminum without heat treatment afterwards leaves the HAZ near the weld as weak as 1/7th of original strength. Meaning it's just going to rebreak, and perhaps more impressively into something actually catastrophic. If you want an option that reall...
by liveforphysics
Jan 04, 2018 12:49 am
Forum: E-Scooter and Motorcycle Photos & Videos
Topic: Mid-mount Hubmonster Madass
Replies: 51
Views: 6606

Re: Mid-mount Hubmonster Madass

Chalo, It won't get pink paint, and my helmet definitely won't be a cat, so I don't think your definition of "cute" will apply. It already looks much better than any of the pics I too portrayed, but in addition to the paint job, a huge hurdle in the looks department IMO is how I integrate a place t...
by liveforphysics
Jan 04, 2018 12:34 am
Forum: E-Scooter and Motorcycle Photos & Videos
Topic: Mid-mount Hubmonster Madass
Replies: 51
Views: 6606

Re: Mid-mount Hubmonster Madass

A controller setup with heavy field weakening could perhaps double your current speed, while compromising no torque over your lower speed ranges, and typically only a small efficiency penalty to achieve that RPM doubling (though some motors evidently suck at it, some motors barely take a hit in effi...
by liveforphysics
Jan 04, 2018 12:30 am
Forum: Battery Technology
Topic: A123 20Ah prismatic cells got expanded - What can be done?
Replies: 26
Views: 431

Re: A123 20Ah prismatic cells got expanded - What can be done?

I've read about making a small puncture with a pin and squeezing the gas out, then seal the hole with epoxy. I can't recommend this, but most accounts are that this works. Having too much gas in the pouch will make it hard to get proper compression on the plates. I heard from Russian speaking frien...
by liveforphysics
Jan 04, 2018 12:18 am
Forum: Motor Technology
Topic: 144Vdc EV Charger
Replies: 78
Views: 5236

Re: 144Vdc EV Charger

I would love to add a few of them to my wifes LEAF if you make the 400vdc version.

Otherwise, I would love to see a trace layout that supports an increased current version (lower turn count magnetics) for folks running 116.4vdc peak pack voltages (Zero, Polaris, Aricmoto, Victory, etc.)
by liveforphysics
Jan 03, 2018 3:27 am
Forum: Motor Technology
Topic: 144Vdc EV Charger
Replies: 78
Views: 5236

Re: 144Vdc EV Charger

Yep, with no isolation in the only can be a DIY'er charger. With isolation it has a shot at being a volume production product if power density and cost are right. I personally love the topology Arlin is exploring using just a PFC stage switch driving a transformer and synchronous rectification outpu...
by liveforphysics
Jan 03, 2018 2:32 am
Forum: E-Vehicles General Discussion
Topic: Looks like Sondors is at it again...(E-car)
Replies: 36
Views: 2498

Re: Looks like Sondors is at it again...(E-car)

Looks like a legit sized hubmotor to me. I wish him well. Hotrodded ES style I bet they rip.
by liveforphysics
Jan 02, 2018 2:10 am
Forum: E-Bike Technical
Topic: Discussion: Motor voltage, timing and gearing's effects on performance and efficiency
Replies: 18
Views: 609

Re: Discussion: Motor voltage, timing and gearing's effects on performance and efficiency

The efficiency penalty would almost certainly be smaller than running a larger diameter wheel, and static/dynamic timing advanced is just field weakening effects done more crudely. Really you need to just try that individual motor and see how to does. It might double its useful RPM range only changi...
by liveforphysics
Dec 31, 2017 2:29 am
Forum: E-Bike Technical
Topic: Discussion: Motor voltage, timing and gearing's effects on performance and efficiency
Replies: 18
Views: 609

Re: Discussion: Motor voltage, timing and gearing's effects on performance and efficiency

https://endless-sphere.com/forums/viewtopic.php?f=30&t=63467 Thanks for pointing out this thread, I will check it out. For every RC car and ebike and EV I personally would max field weakening settings (this is also what OEMs all do). I would have guessed that at some point too much timing/field wea...