Car engines, on the other hand, have a wide enough efficient range to be able to go well past the legal speed limit with only three gears. Four and five add to efficiency, but beyond that they simply add to top end speed and/or acceleration capabilities.
Five and six ratio transmissions actually help cars get good gas mileage by offering a wider range of gearing including a deep overdrive for fuel efficient highway cruising. These cars often have a higher top speed in fourth than they do in fifth or sixth gear.
The exceeded parameter I was referring to was the “between 0 and 100 mph” one. I didn’t comment on how many gears they’d use to get there
That said, you’re right. I think the most gears I’ve seen on a race car was 7. The last time I had a car on the track, it had a 5 speed. I can imagine a few situations in which you’d want more for extra long straights, like the one on the Nurburgring. Sadly, I’ve never run a car there. . Yet.
Even if you are going to stay between 0 and 100 mph, the most efficient gearing for highway cruising is higher than the gearing that allows for maximum top speed. The sixth gear in the late model Corvettes, for example, is there to allow it to get 28 mpg on the highway, not to give it a higher top speed. If you are trying to make this car reach its peak top speed, you have to leave it in one of the lower gears, fourth or fifth.
My motorcycle has been regeared with a 18 tooth sprocket replacing the 17 tooth front sprocket and a 41 tooth rear sprocket replacing the 42 tooth rear sprocket. I didn’t do this because I wanted to go faster, I did it for better mpg and so it wouldn’t be such a buzz bomb on the freeway, having me constantly searching for some non-existant 6th gear.
This bike most likely now can go faster in fourth than it can in fifth.
I understand the logic of compounding gear ratios and although in the vast majority of vehicles it would be a waste of money and an added weight such an option could greatly expand the usefulness of a vehicle. A full size pickup could perform adequately in normal highway driving with an engine under 150 hp and likely burn considerably less fuel than a 300 hp. And with an under drive or 2 speed rear axle the smaller engine could handle as much weight as the larger engine but at a slower pace when loaded. My old 72 Bronco and 53 Jeep had transfer cases which provided a low range when in 4x4 which allowed them to easily pull comparatively huge loads. When pulling a large boat out of the lake either one could easily crawl up the ramp and invariably I would be asked to pull several boats to level ground when their owners saw how easily it could be done. Of course neither of those 4x4s could tow even a small boat on the highway.
My sister in law had a '77 Accord with a 2-speed ‘Hondamatic’.
Had a torque converter, but you shifted manually.
If you’re moseying along stop-and-go you could just leave it in 2.
Yes, the Viper was that way too. But that’s not really relevant to the race car argument. The late model Corvette that you buy from the dealership is not a race car. I’m not claiming to know the intimate details of the Corvettes that they do race, but I would wager that, in the modified classes at least, the transmission is geared according to requirements. In tracks with both technical sections and long straights, I’d not at all be surprised if that 6th gear was useful after all.
My first bicycle was a one speed Western Flyer sold by Western Auto. I got this bicycle in 1950. It wasn’t until the mid-1950s that the 3 speed lightweight bicycles became popular. I would change sprockets for the chain on my bicycle–I had one combination for drag racing and another sprocket set for speed.
One option was an aftermarket coaster brake that had 2 speeds. One shifted from one speed to another by backpedalling. This reminde me of the old Chrysler products with the semi-automatic “lift and clunk” transmissions that had 2 speeds in the driving range and you shifted to direct drive by releasing the accelerator.
The reason a bicycle has such “immense gearing ranges” is because the powerplant is woefully underpowered.
A good recreational (adult male) cyclist can output ~250W for an extended period. That’s 1/3 HP. The bicycle/rider combo probably weighs around 200#, for a “power loading” of 600#/HP.
Given that your typical auto tips the scales at 3600# or so, a similar “power loading” would be a 6HP engine.
If you had such a car, it would no doubt benefit from 27 gears with a huge range; however, given that the typical car only has to move 20# with 1HP (i.e. a 180HP engine in that 3600# car), 3-6 forward speeds suffice.
A good recreational (adult male) cyclist can output ~250W for an extended period. That’s 1/3 HP. The bicycle/rider combo probably weighs around 200#, for a “power loading” of 600#/HP.
However, a rider’s muscles differ from a gasoline or diesel engine in one very important way. An engine can only operate aerobically so that the power that it can put out in a short sprint is no higher than it can put out continuously.
While a bicycle rider may only be able to put out 250 watts long term, he can easily put out 1000 watts or more for a short sprint. That’s over a horsepower.
A 100 pound person climbing stairs at the rate of 5.5 verticle feet per second is generating one horsepower. A really good athlete can probably generate 10+ horsepower for a short burst.
While a bicycle rider may only be able to put out 250 watts long term, he can easily put out 1000 watts or more for a short sprint.
Lance, is that you?
While (ahem) elite-level competitors might output 1KW without struggling, the thought of using the words “easily” and “1000 watts” in the same sentence strikes me as somewhat akin to “jumbo shrimp” or “army intelligence.”
Anyhow, the most critical need for short gearing on a bicycle would be an extended steep hill. Say, 500’ elevation gain or more up a 12+% gradient hill. That’s something that would need to be handled (more or less) aerobically.
(And if you think that’s a far-fetched or extreme example, Google “dirty dozen ride pittsburgh” and you’ll see 12% doesn’t even make their short list. Canton Ave comes in at 37%, with cobblestones.)
A 1000 watt output would be what a man who’s weight is 1000 Newtons would put out if he was raising his weight upwards against gravity at a rate of one meter per second.
1000 Newtons = about 224 pounds. A physically fit 224 pound man sprinting up a ten meter high flight of stairs in 10 seconds would be a kilowatt sustained for 10 seconds. That doesn’t sound that far fetched to me.
Use an actual clock to count off ten seconds and see how long a period of time ten seconds actually is if you feel this level of exertion is superhuman.
I don’t think 1KW is a superhuman level of output; I think 1KW, maintained over a meaningful length of time, is superhuman.
For cycling–in particular, cycling for transportation–10 seconds is not a meaningful length of time. Even your example only gets your 224# guy 33’ off the ground…and that’s an idealized scenario. Most hills exceed 33’ vertical gain, and thus require gearing based on a level of output sustainable over a meaningful length of time.
Ten seconds is long enough to accelerate from a dead stop to cruising speed, which is why you hardly ever see a bicyclist go through all the gears like an 18 wheeler during acceleration. If they are racing, they pretty much all stand on the pedals giving it all they got until they reach their sustained cruising speed and doing very few if any gear shifts. Once they are up to speed, they will hunt for a gear ratio that best suits the particular grade or headwind/tailwind at the moment.
Or at least, that’s how I ride. I don’t like to abuse my equipment and I’m not trying to win a race so I pedal very lightly during the gear change. That interruption of power during the gear changes would cancel out the benefits of going through the gears during the acceleration phase anyway, possibly even be counterproductive.
That’s also why top fuel nitro burning dragsters have all gone to one speed transmissions lately. When you go from 0 to 300+ mph in just four seconds, even a millisecond of power interuption is significant.
Irncpsplhwt, the newest transmissions being developed are a manual automatic. These transmissions are six to eight speeds with manual gears, and clutch.
The clutch pedal is eliminated. An on board computer selects the best gear for the load and driving conditions.Electronics control the hydraulic clutch shifting.
Its called Zeroshift Manual Transmission.Volume 30 #7 Transmission Digest March 2011 goes into detail describing this new generation of transmissions.
Like some other posters noted, big trucks have transmissions with many speeds. The common tranny for an over-the-road truck with big power is an 18 speed. In the old days, two tranmissions (called ‘twin sticks’) were common, and the 6 & 4 combination produced 24 forward speeds, although some were duplicate ratios and weren’t used. The reason a big bore diesel still uses so many gears is because the operating range usually spans only about 400 RPM. So, they need a lot of close ratio gears to keep it in the power band and still be able to accelerate to and cruise at 70 MPH.
I share the OP’s sentiment. I, too, love sailing and not the fuel bill. I want a regular car that gets good mileage around town and on the highway and have the available torque to pull heavy items, albeit slowly. It would be nice to have a crawler gear for uphill pull, a tall gear for highway cruise, and enough gears in between to keep a small engine in its power band. It isn’t hard to built. An 8 speed (or a 2 range 4 speed) shouldn’t require more gears than a 5 speed transmission.
However, I don’t think that’s what most people want. They want to be able to tow a boat uphill at 50+ mph, rather than sharing the slow lane with other truckers. A big pickup truck with lots of horsepower is the way to go.
