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podolefsky
10 October 2011, 0826
Here's a nice paper on chain efficiency. It's for bicycle chains, but gives a good idea of all the variables involved.

Efficiency drops 11% with a 3x increase in RPM. Efficiency also *increases* as power increases - probably because the chain loss is fairly constant for a given RPM, so a smaller % of total power.

There's a lot of math (sorry Ted)...just skip to Table 1.

http://www.g-cog.com/VBMX/spicer.pdf

I think it's interesting to look at how chain efficiency changes compared to motor efficiency. This paper doesn't have data on heavy motorcycle chains, but if it is an indicator then changes in RPM might have as large an effect on chain efficiency as it does on motor efficiency (maybe more). In both cases, you can get more efficiency by lowering RPM. Based on other data that suggests motor efficiency can change as much as 10% by reducing RPM, the combined gain could be as much as 20%.

(Note that I'm just speculating...but it's informed speculation.)

Richard230
10 October 2011, 1440
What I have heard is that O-ring type chains suck up a (relatively) large amount of power compared with non-O-ring chains. A "heavy duty" non-O-ring roller chain is probably best for an electric motorcycle use as it will typically be lighter and more efficient than a large O-ring chain designed for IC motorcycle use where efficiency is not really much of a selling point with most customers.

Another comment is that my experience has been that the fewer cylinders a motorcycle has the shorter will be the life of the rear chain. I maintain my chains and ride my motorcycles about the same. A single-cylinder motorcycle would typically give me about 13,000 miles before the stock O-ring would start to stretch noticeably. My twin-cylinder motorcycles would see around 18,000 miles before the chain started to wear out. However, my 4-cylinder machines would usually go at least 35,000 miles on the rear chain. It would seem that the smoother and more frequent the power strokes of the motor, the less stress is placed on the chain and the longer it will last.

My guess is that a similar chain driving the rear wheel of an electric motorcycle would likely last a very long time, as the power delivery is very smooth with no intermittent hammering such as you would get with an IC motor, assuming it was given proper care and the correct slack adjustment.

EVcycle
10 October 2011, 1527
I Agree!

Our chain of choice.

Renthal - Off Road Chains Renthal chain is only available in the highest grade possible. The best materials
and manufacturing processes are used to offer the ultimate chain in each category, perfectly matched with
Renthal chainwheels for maximum efficiency and longevity.

Renthal R1 Works chain, a premium high strength non o-ring chain available in 420, (Tensile strength 4496 lbf) , 428 and 520 pitch.

frodus
10 October 2011, 1541
I used non o-ring, but it's loud as ****.....

EVcycle
10 October 2011, 1608
I noticed that on our bike, the chain alignment made a difference (and using the largest front sprocket we could) on the noise .
Just a bit off and it would let you know. Normally you would not be able to tell on a ICE due to engine noise masking it.
The 420 was quieter too.

seanece
10 October 2011, 2136
Ahhh, the old o-ring vs. non-o-ring debate. I remember researching this a while back. Here is what I remember (please be patient as I try to find the links).

At startup, or what we will call a "Cold Chain" condition, the non-o-ring chain will cause less loss hands down. This is because the chain lube and the o-ring bind the chain while it is Cold. However, after riding the motorcycle for a while, the friction in the chain begins to warm the o-ring and lube which in turn promotes lubrication and therefore less loss. When mud, gunk and crud is added to the equation, o-rings definitely win.

So, to summarize, in "Cold Chain" conditions, non-o-ring wins. In "Warm Chain" conditions the o-ring and lube wins.

Hope this helps and I will try and supply a link with data (Mmmmmm, data). Let the skewer begin!

ATV's and O-ring (http://www.trx450r.org/forum/128-venom-performance/132450-o-ring-vs-non-o-ring-chain-dyno.html)
Mixxer, about halfway down (http://www.trx450r.org/forum/126-dyno-room/187059-dyno-numbers-o-ring-vs-non-o-ring-chain.html)
Wavehog, about halfway down (http://www.xt225.com/forums/ubbthreads.php?ubb=showflat&Number=66964)

podolefsky
11 October 2011, 0456
I believe there was a study (maybe the same people) that found that a perfectly clean, *unlubed* chain was the most efficient. Lube didn't make a difference, dirt made a big (negative) difference. I'll try to dig that paper up.

I'm also thinking that if friction losses are constant, then as a % of total power, a motorcycle chain with 5-10 kW will be less of a hit than a bicycle chain at 100 W.

teddillard
11 October 2011, 0503
hmmm. Seems kind of all academic to me. First, if you run the same quality chain at a larger size, it's going to last longer, period, right? Having gone through eleventy million chains and sprockets over my riding career, I can't see the point of reducing the life of the chain intentionally for a small gain in efficiency. Just being practical here.

Now if your running a 420 to keep the rear sprocket size down, well, sure... But both the bikes I've done had 520, and it seemed like if it was the right choice for them, (a 500 and a 350) then it'd be smart to stay with it. Plus I can use the stock sprockets.

O-ring vs non O-ring? meh. I like strawberry ice cream. :D

Noah, I read a study somewhere that a chain in an oil bath was the absolute highest efficiency. Not sure where that was at, though.

podolefsky
11 October 2011, 0519
Yeah, plus non-O ring chains are a PITA. I like the simplicity, maintenance wise.

I'd be really surprised if the loss was more than a % or 2...like 100 W out of 10 kW.

podolefsky
11 October 2011, 0539
I Agree!

Our chain of choice.

Renthal - Off Road Chains Renthal chain is only available in the highest grade possible. The best materials
and manufacturing processes are used to offer the ultimate chain in each category, perfectly matched with
Renthal chainwheels for maximum efficiency and longevity.

Renthal R1 Works chain, a premium high strength non o-ring chain available in 420, (Tensile strength 4496 lbf) , 428 and 520 pitch.

do they come in gold? I need my bling...

EVcycle
12 October 2011, 0326
do they come in gold? I need my bling...

As a matter of fact....they are gold colored....will that do?

teddillard
12 October 2011, 1312
mmmm. colors.

http://lh4.googleusercontent.com/public/wDdfJ-EzFBsVNOaWCtqwOckOcvATdG_5-2F-le7gL7LK5YTu5yG5YCj6RnhZiuESqn_QKLJNtgVJRYb3Gxx-0E9nleHK4kZN_18Y6OIBXNct9srrqR8RWHctk5BAJi-TDMV76szydvCGUa-FzFCu8MESkp7BTlRg42AS0EvEX9eJrjY4GOGml4o7vhW_-E2Z0_nM

http://www.amazon.com/EK-520MVXZ-Chain-120-Chrome/dp/B002C5YQKQ