Recent content by MadScientist

Most spokes failures are due to stress at the elbow caused by unloading when the tire in the vicinity of the spoke pushes against the ground or an obstacle (e.g. pothole). Spoke nipples can loosen if the spoke becomes slack, effectively loosening the rest of the wheel and increasing the...

Rats, I've been found out. Luckily, I possess l33t sk1llz and have already planted posts in this very forum, retroactively making it look like I announced the conspiracy, er, I mean support for Josh, last Wednesday. But it goes deeper than that. Are you ready to take the red pill, my friend...

To each his own. I think swapping packs is just dandy as long as you carry the spare along with you. At least one ebike last year swapped packs somewhere close to the top. I don't know about the Optibikes. The organizers have made it clear that motor vehicles are not allowed on the course...

It would be funnier if it were true. I can't speak for all Optibike owners, but those of us who participate in the Google group are genuinely enthusiastic about all sorts of ebike developments. One of us (me) is even sponsoring a competing bike using Ron Rocha's chain puller drive. I'm...

Are you suggesting that showing up to this USA Cycling sanctioned Fun Ride with the 6000W motorcycle-with-pedals mr greenwhatever was foaming at the mouth about is in good taste? You seem to have trouble understanding that this is a bicycle ride, and that motor vehicles are specifically prohibited.

Thanks for a helpful and informative response :roll: Perhaps you can provide something more concrete? Are you disputing the fact that engines run hot when the mixture is leaned from optimal? Perhaps you believe humid air is a better conductor of heat? I'm willing to discuss this so we can...

http://www.google.com/search?hl=en&q=why+does+a+lean+engine+run+hot I'm not an internal combustion engine engineer and don't have a complete understanding of the reasons for the phenomenon. I can tell you it is plainly evident when tuning model airplane engines, and is widely reported elsewhere.

I don't think so. The specific heat of dry air and water are roughly 1.01 and 1.86 kJ/kg.K, respectively, depending on conditions. However at standard conditions 100% humid air is only 3% water vapor, and has a specific heat of 1.01*.97+1.86*.03 = 1.035, a mere 2.5% increase (up to 6% increase...

That does not make sense. A BLDC motor's Km constant is independent of winding. In other words resistive losses are a function of torque, not turns. Iron losses (eddy currents) depend only on n*I (turns times current) - they are determined by torque (and speed) and are likewise independent of...

Eric, you truly are an idiot. No, I do not work for Optibike. Thanks for the laugh. Unfortunately you are, overall, far more annoying than funny. Still I figure one more post here to set the record straight is justified despite the adage "please don't feed the trolls". Regardig your battery...

Obviously you don't know what I ride, nor much else about me. Calling me a hypocrite was an act of ignorance. You owe me an apology. Gotta love them conspiracy theories. In the real world, where I ride, Jim and Kyle ran stock Optibikes last year. I assume they plan the same this year. The...

Check your facts, my friend. I run a small (44 tooth) chainwheel on my Optibike for insane climbing, but it limits my top speed (without pedaling) to a road legal 20mph. The power is also legal: 800W * 85% efficiency (estimated) = 680W, safely below Colordo's 750 W limit. It rides like a...

You completely miss the point. This is a private bicycle ride. The course is "closed to motor vehicle traffic". If you bring a sufficiently powerful electric-motorcycle-with-pedals, someone is bound to complain and there will be consequences. The police can issue a ticket for riding a non-street...

Oil on the threads only allows the nipples to unscrew if the spokes lose tension! Otherwise, friction (particularly nipple against rim) prevents them from unscrewing. Again, slack spokes are bad wheel juju, but if you are worried about it use some spoke prep (or linseed oil) which lock the...

I have only built wheels with 14 or 15 gauge (preferably butted) spokes with 56 tpi threads, so I can't speak from experience here, but with fewer threads per inch, a thicker spoke should have a similar thread ramp angle, allowing you to reach the same tension. You can check spoke tension with...