| Author | Message | ||||||||||||||||||||||||||
     Glitch |
Oh and by the way... I sure am glad that first page finally archived! | ||||||||||||||||||||||||||
| Sifo |
Oh and by the way... I sure am glad that first page finally archived! AMEN brother! Amen! | ||||||||||||||||||||||||||
| Mr_grumpy |
E J Potter (aka The Michigan Madman) didn't use a gearbox or a clutch, just a Chevy V8 in a Harley frame with direct drive to the back wheel. He'd just wind it up & push it off the stands. I watched him run in England, helluva show. Just to address the gearbox issue. Gearboxes eat enormous amounts of power as the whole thing has to be turning all the time. An automatic box with a torque converter even more so. Many years ago when synchro boxes were coming into use on heavy trucks a study was done where I worked on 2 rigs identical except for the box, one was a Fuller Roadranger 13sp "Crash" box & the other a ZF 16sp Synchro. The Fuller ran nearly 1mpg better than the ZF. When they were tested the ZF was found to be drawing nearly 20horses more than the Fuller. Why did crash boxes die out then? any monkey can drive a synchro box, a Fuller takes practice & skill. If you want to see what I mean go find a vehicle gearbox of any sort, make sure it's filled with oil, pick a gear, then try turning the input shaft with your hand. Now imagine how much that resistance is increased when it's under load!! And how much work has to be done to overcome it. | ||||||||||||||||||||||||||
| Sifo |
Hey Grumpy, I've always wondered what kind of MPG tractor trailer rigs tend to get on the highway. Got an estimate? | ||||||||||||||||||||||||||
| Jaimec |
Grumpy, what you say makes a lot of sense to me. Every single gear inside a transmission is another source of friction and drag on the engine or motor. Despite Blake's insistence, I see no advantage to putting a transmission on an electric motorcycle. | ||||||||||||||||||||||||||
| Sifo |
Despite Blake's insistence, I see no advantage to putting a transmission on an electric motorcycle. I'm not convinced there's no advantage. I'm just not convinced that it's the panacea that Blake is making it out to be. I thought one of the selling points of electric bikes was the strong acceleration at low speeds. Blake is claiming them to be weak at slow speeds. I'm curious where this is coming from? Any links? At any rate, we are talking about bikes that are powered to compare to 125-250 cc bikes. Most experienced riders don't even consider these because of their lack of power. If you want to address that on the electric you are going to have to up the power considerably. I don't think doing that will get them into a market niche that will produce sales though. | ||||||||||||||||||||||||||
| Jaimec |
With battery technology the way it is today, every ounce of power eaten up by turning the gears in a transmission is power NOT being put to the ground in the form of actual movement. The current (forgive the term in this context) goal is to go as many miles between recharges as possible. Maybe when it becomes as easy and convenient to recharge a battery as it is to refill a fuel tank (and you only have to do it as often) can we look at possibly including some kind of transmission. But as the technology stands, I see no appreciable return on the investment. | ||||||||||||||||||||||||||
| Glitch |
Good points there Jaime | ||||||||||||||||||||||||||
| Sifo |
With battery technology the way it is today, every ounce of power eaten up by turning the gears in a transmission is power NOT being put to the ground in the form of actual movement. Exactly. And a big part of that is regenerative braking. This is hard to get right with a single speed direct drive. Add a variety of gear ratios and a user activated clutch like we are used to, and most of us probably enjoy, and the programing for the braking gets far more complicated. Throttle blipping on downshifts won't help matter either. Many things that we are used to with gas has to change with electrics. One down side I see with doing an electric bike is that being rear wheel drive also means rear wheel regenerative braking. Some people seem to think that most of the braking power comes from the front wheel though. Seems you will lose lots of potential energy driving around town where you brake a lot. I can see where they may go to two wheel drive with hub motors. Not the hot ticket for great handling though. Interesting to think about. Lot's to keep the engineers busy. | ||||||||||||||||||||||||||
| Glitch |
I saw one design that had regen braking built into the front forks. Finding this stuff on the web is getting more difficult though, as it seems there are tons of concept bikes these days. | ||||||||||||||||||||||||||
| Mr_grumpy |
Sifo most current European tractor trailer rigs, running max 40t on 5 axles, cabover with around 400-500 hp will get 6.5 - 7 mpg or better. Back in the day with a 14litre Cummins 320 & a Fuller we were getting about 4.5 - 5 Mind you we ran like demons then, these days with speed limited to 56mph all the onboard data logging etc, it's a different kettle of fish. | ||||||||||||||||||||||||||
| Blake |
The Dyno plot doesn't lie. Which is better, dark green 3-speed gearbox, or the direct drive single speed? This is even a question? Seriously?.  Y'all are nuts. An electric motor isn't magic. E-bikes with direct drive have horrible acceleration compared to comparable ICE bikes with a gearbox. "I don't see the need" Straw man. Since when is higher performance a "need"? Come on! I'm talking "want"! Snort, grunt-grunt... moe-powah!!! There is little to no loss of drive when shifting like a man.  In fact aggressive up shifting can generate a real kick in the pants as the faster turning motor dumps its excess inertia into the drivetrain. It's a very good thing. | ||||||||||||||||||||||||||
| Glitch |
Which is better, dark green 3-speed gearbox, or the direct drive single speed? Are all those electric motors in the electric bikes the exact same motor? It'd make a difference would it not? I don't know, I can't find the article. E-bikes with direct drive have horrible acceleration compared to comparable ICE bikes with a gearbox. What is a comparable ICE bike? 125? 250? If so they are far from superbikes. The superbikes that are actually racing are direct drive, and from what Chip Yates said before her retired, they're competitive. But if it's being manly and needing a clutch and gear box, don't get an electric bike that can only give you performance of a 250. I'm talking "want"! Well then there's no argument at all, none what so ever. I was just trying to figure out why they didn't have a gear box. "The most advanced electric motorcycle in the world" (according to Popular Science) won the Isle of Mann electric TT. That was the Motoczysz, and to me is pretty manly. http://www.motoczysz.com/ | ||||||||||||||||||||||||||
| Sifo |
Don't forget that the mass of the primary drive, clutch, gears, and all the associated shafts are rotating mass that has to be accelerated twice. Once in rotation, and once in a straight line down the road. Sometimes simplicity works well. | ||||||||||||||||||||||||||
| Blake |
>>> What is a comparable ICE bike? Internal combustion engine bike with similar weight and power. >> But if it's being manly and needing a clutch and gear box, don't get an electric bike that can only give you performance of a 250. Exactly.  . And the thing is, what I've been trying to explain, if it has the same peak HP of a 250, it won't perform nearly as well accelerating from a stop or low speed. Think of the gearbox as a torque multiplier; the lower the gear, the more the motor torque to the rear wheel is multiplied. | ||||||||||||||||||||||||||
| Blake |
A 125 or 250 can be great hooligan fun, especially in first gear. Not so for a single speed e-bike equivalent. | ||||||||||||||||||||||||||
| Mr_grumpy |
You can wrap your words up in that fake Dyno chart Mr Blake, shame on you a qualified engineer, faking data like that. I want film of you eating that.  | ||||||||||||||||||||||||||
| Sifo |
Pretty much equally important to off the line acceleration is weight. Adding a primary drive, clutch, gearbox, and misc. items such as clutch lever & cable, shifter and linkage, and oil and you are adding a significant amount of weight. Then you have additional losses from friction. Now I'm not an engineer, but I do know that the equation for acceleration of mass isn't a linear equation. If you add 20% to the mass the energy for the same acceleration is going to have to go up by more than 20%, is this not so? Then you have the issue that the rotating mass (primary drive, clutch, gears and shafts) all have to be accelerated not only with the vehicle, but also in rotation. That drains lots of energy. Then you still have to package the whole thing, certainly adding size to the bike. All the extra weight means beefing up the frame/suspension to carry the extra weight meaning even more weight gain. All this with a system that only gets you about 15 miles when ridden fairly hard, the range is going to go down even more. Solution to that of course is adding battery capacity and the associated weight. At this point maybe we should just start adding chrome to the thing!  | ||||||||||||||||||||||||||
| Jaimec |
 Sifo, that pretty much sums it up. Blake is stuck in an ICE world and can't seem to grasp that a transmission MIGHT be an interesting marketing gimmick with an electric motor, but that's really ALL it would be. | ||||||||||||||||||||||||||
| Mikef5000 |
A 125 or 250 can be great hooligan fun, especially in first gear. Not so for a single speed e-bike equivalent. My 250 will throttle the front wheel up at 10 mph, and will cruise all day long at 65 mph (90 mph max). I'm more than willing to use my bike in a comparison... with ~25 hp, it'd be perfect competition for the Zero. The only time I can imagine direct drive to be enjoyable, is when there is so much power on hand that the lower power at lower rpm is still excessive. Not unlike that dragster posted above. When we're talking sub-20hp powerplants, I'd think they could use any (mechanical) advantage possible. | ||||||||||||||||||||||||||
| Sifo |
I'm not sure that the WR250R is that great of a comparison. 24.46 hp at the wheel...  vs. the 20.8 hp of the Zero. That's a 15% jump in power! That's before you add the drag of a primary, clutch, and transmission to the poor little thing. The Zero already weighs more too. How much will the new hardware for gears add? By the time your done you are going to have a bike with under 20 hp that tips the scales at upwards of 350 pounds. Find me a bike with those specs on gas and then we can compare. | ||||||||||||||||||||||||||
| Mikef5000 |
Well hot damn! I thought it was 25 at the crank. It's sounding more and more like these electric bikes are designed to replace the 150cc and smaller scooters. I guess there's a market for that, and more power to them, you've got to start somewhere, but they're not going to get real public interest till they can compete with real motorcycles. My personal opinion of course. | ||||||||||||||||||||||||||
| Sifo |
Actually at 15.5 HP and weight of 302 pounds the Honda SH150i may be pretty close in terms of power to weight ratio that Blake is trying to turn the Zero into.  http://www.motorcycle.com/manufacturer/honda/2010- honda-sh150i-review-88471.html I'm not going to say that it wouldn't be an effective and fun way of commuting, but I don't see it as a hooligan bike. At half the price of the Zero it's a bargain though.  | ||||||||||||||||||||||||||
| Sifo |
Perhaps a Honda Rebel at 331 pounds with 17.5 hp is a good comparison.  http://www.topspeed.com/motorcycles/motorcycle-rev iews/honda/2009-honda-rebel-ar68276.html Puts it squarely in the rider training bike area.  MSRP at about $4,200 too! | ||||||||||||||||||||||||||
| Mikef5000 |
Well if this doesn't prove the benefit of a transmission, I'm not sure what could: Honda Rebel: 15.9 HP 333 LB 0-60 MPH @ 11.0 Sec. 1/4 Mile @ 17.81 @ 70.06 MPH Brammo Enertia 15.3 HP 332 LB 0-60 MPH @ 19.6 Sec. 1/4 Mile @ 20.8 Sec. @ 60.1 MPH The Zero and WRR are almost as close as well (much closer than the Ninja 250 or CBR 250 would be): WR250R 23.5 HP 301 LB 0-60 MPH @ 6.7 MPH 1/4 Mile @ 15.51 Sec @ 80.88 Zero S 20.5 HP 282 LB 0-60 MPH @ 11.9 Sec 1/4 Mile @ 19.2 Sec @ 63.9 Here's where I got my information: http://www.motorcyclistonline.com/features/122_081 0_honda_kawasaki_suzuki_yamaha_mpg_comparison/view all.html http://www.motorcyclistonline.com/comparisons/122_ 1011_brammo_enertia_vs_zero_s/viewall.html I couldn't find any scooter details, but I didn't look very hard either. If someone wants to find details for a 150cc scooter to add to the comparison, more power to ya. I was simply genuinely curious how these new electric bikes stacked up against the IC 'competitors', and my answer is that they don't (yet). | ||||||||||||||||||||||||||
| Reepicheep |
Less difference than I expected Mike. Good info. I have a 225cc bike that will scare the crap out of all but the most serious riders. It weighs less than I do, and probably pulls 30 to 35 RWHP. Stupid fun. | ||||||||||||||||||||||||||
| Blake |
>>> Less difference than I expected Mike. Are you comparing the 0-60 MPH times? My reaction is that the difference is even greater than I expected. The 1/4 mile times are less divergent due to the limited high speed acceleration of all the bikes. In top gear, they are all about equal. | ||||||||||||||||||||||||||
| Sifo |
Mike, Those comparisons in performance are certainly interesting, and worthwhile. I'm not sure that they really tell much of the story about adding a transmission to an electric though. They are however real world comparisons of electric vs. gas though. When you compare them on performance per dollar spent you get a dramatic difference too. I'm all for letting the consumer choose what they feel suits them best though. I just hope I can still choose what's right for me in the future. | ||||||||||||||||||||||||||
| Blake |
In both comparisons the e-bikes are approaching double the time to go from 0 to 60 MPH.
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| Mikef5000 |
In top gear, they are all about equal. (Except both electric bikes top out just over 60, while the Rebel will pass 75, and the WRR 85.) Understandably, they are made for city riding, so speeds north of 60 are not as important. Still, not comparable. I'm not sure that they really tell much of the story about adding a transmission to an electric though. They are however real world comparisons of electric vs. gas though. You may be right about the transmission. All I'm focusing on is the real world comparison aspect of them. (Message edited by Mikef5000 on April 07, 2012) |
