M 750 is my fave. There is a modern equivalent I think. Lovely big bushes. Shifts into a 36.
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What is this about? Smaller wheels burn less gasā¦ Because CDA, rolling resistance or because they donāt change the speedo setting and it reads too hi?
(The new Prius).
maybe because the larger wheels have more rotational inertia and unsprung weight?
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IMO thereās no way the difference is that big. That would be a 20% delta. Iām not even sure wheels account for 20% fuel consumption overall, let alone differences between wheels.
BTW 17" vs 19" ātiresā is a complete misnomer. Iām 99.9% sure the tires are the same size, the rim size is whatās different.
You would think. Altho my Prius speedo is so frikken inaccurate itās dangerous. At 109 kmh itās only 100 kmh. So if I drive at an indicated 100 kmh I have people tail gating me. Those stats above seem rediculous to me.
Thatās normal. Every car speedo is off by about that much. I believe itās to avoid potential lawsuits if the speedo were to be off the other way. Then you could get a speeding fine while your speedo says youāre doing the speed limit.
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Itās the worst Iāve ever seen, by a very big margin.
Both my cars are off by 7 to 10 kph in the 100kph range.
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I pot 8ā tires on my Prius 3 years ago and Iām still driving around on the first tank of gas
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this is a big thing and is real. itās not just the prius. a few different EVs sell a āmega rangeā version like the ford mustang mach-e california route 1 edition. that car is lightened and specifically has smaller wheels than the ānice looking premiumā trims of the same car.
the chubbier tires are nice and smooth and donāt disrupt the airflow as much.
they ALSO have less rolling resistance.
AND they are much lighter to spin up every time. i donāt think unsprung weight matters to range, but the weight difference definitely does.
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Does that mean my rim brake 26 inch Rat-trap passes are more effiicent than my 700 wheels? They certainly feel fast when accelerating away from the lights, in an urban setting.
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When it comes to acceleration, a gram in the rim/tire counts 2x as much as a gram in the frameā¦ but Iām not seeing how that alone would account for 20% range difference, there must be a bunch of other differences between these trims
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is this what inspired the whole 650c tri bike thing? smaller wheel more efficient plus some stuff about wind speed at the top of the tire?
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at least when it comes to the tesla model 3, the smaller wheels look kinda funky but are much more aerodynamic.
the unsprung weight is real though (although it doesnāt affect mileage). apparently the suspension dynamics folks made a series of sad faces at how much the 19" premium wheel option weighs, but the marketing/sales folks said the aero wheels looked too derpy and not have a premium option to upsell customers on was unacceptable.
Smaller wheels arenāt more efficient, especially on bicycles. Lighter wheels are more efficient, but that aināt quite the same thing.
As for automotive wheels, itās amazing how incredibly heavy they can be. The 19ā wheels on our Mazda 3 are 35lbs on this āfuel efficientā car and Iām sure to some degree contribute to our inability to achieve EPA advertised fuel economy. By comparison a ālightā 17ā wheel would easily be under 20lbs. I think I had a set for my WRX that was 15ish.
looks at 140+ lbs stack of summer tires on 21" wheels that need to be swapped on to our EV soon, sheds single tear
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A preface for how shartq this q is:
I was in high school when the forum started
I am in my mid-30s
I still have no idea how to look at vintage mtb and determine how it size translates to road bike
Shartq: how?
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I can buy an old mtn bike from the pics alone. I have no idea what size road bike frame I should buy.
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The trend back then was long and low like the racers, like 120mm stems and short stack with 52-56cm bars, which Iām guessing youāre not after. I ride a 55-56cm road bike and would, on paper at least, ride an 18" MTB. But an 18" retro MTB is not gonna fit the way I want it to-- Iām not young and stretchy anymore. So I essentially translate that 55-56cm to inches and hunt for 21" retro MTBs. That seems to work much better with a modern ATB style fit.
So unless youāre freakishly tall youāre probably fine to convert your road size to redneck measurements and start there. But 22" is pretty much the upper limit for old MTBs, maybe a rare 23" if youāre lucky.
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We are the same but opposite and thatās neat
This is great because in trying to copy you
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