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/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> % power loss, chain verses belt /cgi-bin/YaBB.pl?num=1258732716 Message started by Routy on 11/20/09 at 07:58:36 |
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Title: % power loss, chain verses belt Post by Routy on 11/20/09 at 07:58:36 Search? Nothing as always ! What is the % of power loss thru belt drive vs chain? I used to be into "Bent Bikes", (hobby) even built many 2 wheel, several 3wheel, and one 2 person 4 wheel. The derailler chain drives were (and still are I guess) the most efficient at 98%. The internal geared 3-15 sp hubs were only 85%, a big loss regarding HPVs. Thats why chain drives still rule on 99%(?) of all bicycles. |
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Title: Re: % power loss, chain verses belt Post by Midnightrider on 11/20/09 at 08:15:01 The belt is more efficent because it is lighter. I read this years ago. You have more options of changing your gearing with a chain drive but for overall effiencey belt drive is best. |
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Title: Re: % power loss, chain verses belt Post by Serowbot on 11/20/09 at 08:52:10 Yup,... friction and mass... 1. belt 2. chain 3. o-ring chain 4. shaft |
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Title: Re: % power loss, chain verses belt Post by justin_o_guy2 on 11/20/09 at 09:14:59 I bet the HD style belt is more efficient than ours. Especially when ours are squeaking, because making the noise uses energy. I always thot a chain was the #1 efficient,,, & belt was #2,, I guess Ill have to change that chapter in my book. |
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Title: Re: % power loss, chain verses belt Post by Routy on 11/20/09 at 09:32:42 Wait just a minute ! This forum is full of surprises today. I'm not much up on this stuff, but up untill these replies, I would have bet my last buck that chain is #1 in efficiency,.....and I'm not sure I wouldn't still bet it. I'd sure like to know how the belt being #1 was arrived at. IMO, if a belt was more efficient, we would have seen them on bicycles (HPV) a long time ago,....especially the single speeds. Even a 1% difference make a big difference on HPV (human powered vehicles) |
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Title: Re: % power loss, chain verses belt Post by justin_o_guy2 on 11/20/09 at 10:27:12 Check this out.. Im totally shocked www.chiefdelphi.com/media/papers/download/2388 |
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Title: Re: % power loss, chain verses belt Post by bill67 on 11/20/09 at 10:45:09 Now we know why the S40 is so fast |
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Title: Re: % power loss, chain verses belt Post by Serowbot on 11/20/09 at 10:46:01 In the days before toothed belts, the belt tension had to be very high, and chains and gears could move more freely... With toothed belts, belts can move freely and their lighter mass gives them an advantage... unless you over-tighten them... Belts can't run through a deralier system on a bicycle, and so are limited to single speed or different gearing systems... Stronger materials, like Kevlar, are letting belts get lighter and smaller and more efficient, but they still don't have good lateral flexibility needed to run through a deralier... So, it's the inefficiency of the necessary internal gearing that makes belts impractical for bicycles... Motorcycles don't have that problem... I'm not quoting any particular source here,... just what I've read and heard... some would argue different, but it makes sense to me... more so on motorcycles that bicycles though... |
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Title: Re: % power loss, chain verses belt Post by verslagen1 on 11/20/09 at 11:36:34 A while back, there was a move to go to infinitely variable transmissions. These are the kind that use a v belt and pulleys that spread or squeeze together to change the diameters. They didn't catch on because of the inherent losses. There are a few bicycle transmissions vested in the technology, but they are expensive. |
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Title: Re: % power loss, chain verses belt Post by bill67 on 11/20/09 at 11:48:03 Theres a few cars that have those transmissions in them.They seek the highest gear ratio they can and have full power when you put the petal to the metal. |
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Title: Re: % power loss, chain verses belt Post by Routy on 11/20/09 at 13:11:08 Thanks Justin, I won't argue w/ that. When do ya get too old to learn something new ? And come to find out, there are bicycles using belt drive, and sounds like we will see more in the near future. It is the new light and very thin and flexable belts that create very little friction, that has changed all this. But, I thought I had read someone here reporting a substancial higher top end speed after switching to chain. But that must have had to do w/ changing ratio at the same time,....I guess. I'm liking my belt drive better all the time ! :) |
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Title: Re: % power loss, chain verses belt Post by serenity3743 on 11/20/09 at 13:47:09 Yeah, the chain conversion allows for highway speeds at lower RPMs because of the sprocket ratios, not because the chain is more efficient at transferring power, because it's not. |
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Title: Re: % power loss, chain verses belt Post by justin_o_guy2 on 11/20/09 at 14:32:44 Im not sure a derailer couldnt be built & a belt designed to run thru one, but tensioning the belt so it wouldnt slip would be quite a trick, but not impossible, IMO. Chains dont require near the tension. Variable pulleys can give a CVT ( constant variable transmission,, generally is what thats about, Im sure I missed it some). The weight, cost & complexity of a belt derailer & the difficulty ( IIRC, a chain has to be broken & put on using a master link, but its been a long time) of putting a belt on a bicycle makes the chain the first choice. A belt that would fit on a bicycle would need to be pretty narrow. |
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Title: Re: % power loss, chain verses belt Post by Serowbot on 11/20/09 at 14:51:01 and toothed on both sides.... |
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Title: Re: % power loss, chain verses belt Post by Yonuh Adisi on 11/20/09 at 15:13:57 I don't understand how a shaft is not the more efficient. After all it applies the power directly without the stretch of belt or chain which robs power. A shaft does not have that problem. So maybe ya'll can explain that to me. |
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Title: Re: % power loss, chain verses belt Post by bill67 on 11/20/09 at 15:32:17 Years ago I read you lose 10% of the power with shaft drive. You are reversing the force. |
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Title: Re: % power loss, chain verses belt Post by Charon on 11/20/09 at 15:43:30 The problem with the efficiency of a shaft drive on motorcycles has to do with the gearing required to change directions. Motorcycle engine crankshafts and transmission output shafts generally run transversely, as does the axle. The drive shaft runs fore-and-aft. So a bevel gear is used to change the transverse motion of the transmission to the longitudinal motion of the shaft, and another bevel gear changes the shaft direction to the wheel direction. Some motorcycles such as Gold Wings, Moto Guzzis, BMWs and some others have longitudinal crankshafts, so only have one direction change. Way back when the Wright brothers were designing their Flyer, they were told that chain drive was pretty lossy. They did a good bit of experimenting, and as I recall reading they came up with an efficiency of about 95% for chain drive. They went on to successfully drive the propellers of the Flyer with chains. |
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Title: Re: % power loss, chain verses belt Post by Routy on 11/20/09 at 15:54:48 I understand the inefficiency of shaft drive,....its not the shaft, but the gears that involved w/ it. We're talking a gearbox here, in which we have friction from not only the gears meshing together having to squeeze the oil out, but all the bearings involved, which also have resistence from the oil they run in. Now here is what really surprised me,.... years ago already. Why are the most efficient cars all front wheel drive ? Supposedly its because all the shafts and gears are turning inline or parallel w/ each other. Supposedly anytime the power turns a 90 deg corner,...such as a ring and pinion,... such as in a shaft drive motorcycle, more power is lost than if the shafts are all turning in the same "plane".....is that the right word? If that is all true, I really don't understand that. On edit, Sorry, the above post says most of it all. It wadn't there when I left ;) |
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Title: Re: % power loss, chain verses belt Post by Yonuh Adisi on 11/20/09 at 16:50:25 Okay, I think I understand what ya'll are saying then. But ya'll are referring to the typical v-twin where the cylinders are in line with the bike frame correct? If so, then in the case of my brother's GL500 where it is a transverse v-twin, would the shaft be more efficient than a belt or chain? Just curious not trying to spark an argument or anything. |
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Title: Re: % power loss, chain verses belt Post by justin_o_guy2 on 11/20/09 at 16:56:32 Shaft drive has to overcome the bearings & oil, so it loses a certain amount of horsepower. Until today, I would have said chain is the most efficient, then belt, then shaft..& I woulda been wrong. |
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Title: Re: % power loss, chain verses belt Post by bill67 on 11/20/09 at 17:18:40 Drive shaft also loses energy trying to lift the back end of the motorcycle. |
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Title: Re: % power loss, chain verses belt Post by Routy on 11/21/09 at 05:10:29 Ok, I'll bite,.... why/how is the shaft drive trying to lift the back of the motorcycle ? ::) 7E7570702A2B1C0 wrote:
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Title: Re: % power loss, chain verses belt Post by bill67 on 11/21/09 at 05:19:47 Instead of the back going down when accelerating It is lifted up,Drive one and you will see. |
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Title: Re: % power loss, chain verses belt Post by Routy on 11/21/09 at 05:31:56 Not doubting your word, but can you answer the "why" part ? I'm just thinking that no matter what drive it is,.....when the power is applied in a forward gear, 2 things are trying to happen,..... the rear wheel is trying to turn forward, and the front wheel in trying to lift. Which ever has the least resistence, is going to happen :-? 787376762C2D1A0 wrote:
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Title: Re: % power loss, chain verses belt Post by bill67 on 11/21/09 at 05:35:49 I think instead of the force coming from the front of the bike its coming from down low at the rear of the bike. |
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Title: Re: % power loss, chain verses belt Post by nicka on 11/21/09 at 08:32:12 I think that this is what happens; the pinion, which is attached to the drive shaft, engages the front side of the crown wheel, which is attached to the back wheel. As the pinion starts to turn it initially climbs up the crown wheel so lifting the tail of the bike. Once the bike starts to move the crown wheel descends and with it the pinion. |
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Title: Re: % power loss, chain verses belt Post by 97ram360_06s40 on 11/21/09 at 08:49:57 I read in v-twin mag last year that the chain lose 5% belt 8% and 15% for the shaft power to the rear wheel. Thunder manufacturing recently came out with a chain conversion for the meanstreak why cause the shaft looses to much power. |
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Title: Re: % power loss, chain verses belt Post by Serowbot on 11/21/09 at 09:11:37 On my DP bike, only a 225cc,... there was a perceptible performance difference between an o-ring chain and a conventional chain... I'd guess a least a 1/2hp, and it was only a 428 chain. That would be more on a 520 or larger chain... |
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Title: Re: % power loss, chain verses belt Post by verslagen1 on 11/21/09 at 09:45:39 From memmory, bevel drives are inherently inefficient. The teeth are trying to slip by each other transversely like a worm drive. And with bevel drives you have something not present in others... thrust bearings. |
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Title: Re: % power loss, chain verses belt Post by Routy on 11/21/09 at 19:44:46 Wow, now we're back to the belt back in 2nd place for most efficient, which I know they used to be. But I know we're talking about the newest hi tech belts, some of which are paper thin, almost no resistence, and very expensive. I don't doubt that these are as,....or more efficient than chain. |
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Title: Re: % power loss, chain verses belt Post by ineclipse on 11/24/09 at 20:42:36 I recall a conversation similar to this that turned into an argument recently. Like so many do, someone knowing something without knowing why. Myself, thinking that a shaft would be the most efficient, and my friend knowing it was the most inefficient, couldnt explain why. He at the time said, as I have since then thought, that chain was more efficient. Riding our bikes with chains and belts, with equal gear ratios, i think a lot of us can concede the fact that chains transfer energy a lot quicker, and sometimes with unforgiving consistency. Still dont understand the shaft drive idea, especially lifting the back of the wheel up. Need a diagram for that. |
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Title: Re: % power loss, chain verses belt Post by srinath on 11/24/09 at 20:56:09 I once read some engineering specs about why it was this way ... cant remember possibly due to uneven stretching etc ... When new, Chain is almost 98%, belt is ~96% and shaft is ~90% or less. The chain as it ages, drops below belt quite slowly ... through 1/2 its life chain is par or better than belt, but past the 95% it drops rapidly to as poor as 75 before people replace it. Belt OTOH, is 96 when new and super stiff and slippery with oil from manufacturing, then it slowly climbs with a few 100-1000 miles to a 97 or so and stays there for a long time. Shaft too first increases with break in, then stays there forever. So Chain, belt, shaft when new, belt, shaft and chain when they are about to die and belt, chain and shaft @ the 1/2 way point of the chain's life. Cool. Srinath. |
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Title: Re: % power loss, chain verses belt Post by justin_o_guy2 on 11/24/09 at 21:45:24 Soooo, when should I mod the Savage to a shaft? Im just so confeeewwwzed,, |
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Title: Re: % power loss, chain verses belt Post by srinath on 11/25/09 at 10:27:31 If it were up to me, everything I own would have a belt. The bloody GS500 should have been sent with a belt from the factory ... Cool. Srinath. |
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