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  • Retrorockit
    replied
    My bike goes 35mph with a BBSHD. It's a 2004 Gary Fisher Solstice comfort bike. Basically 26" MTB with a long head tube and upright riding position. I'm running a 50x11t top gear. It will go 30 in the 50x13 7th gear @ 100rpm, or at 90rpm in top gear. No aero tricks. If I want range I ride slower.
    Here's the Sheldon brown gear calculator. For gear units selsct a cadebce you like, tire size, casette/IGH, and a few chainrings to try. 90 rpm for cruising, and 100rpm for banzai runs are good places to start.

    I have another bike which is an XC Softtail. Ive run 26x2 tires, pure slicks for street, knobbies for offroad, and 700cx28mm for road work. The Schwalbe Big Appple Plus from the Gary Fisher will fit it also except I went bigger on the rear brake rotor. 4 wheelsets for 1 bike. Once you go to disc brakes this is easy. There are shims for casette and disc brake rotors to make them all interchangeable.
    I don't have any 27.5 because they didn't exist yet at the time I did these mods. That would be better than the skinny 700c setup.
    Last edited by Retrorockit; 10-27-2019, 06:02 PM.

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  • tklop
    commented on 's reply
    Originally posted by ncrkd View Post
    ...I'm focusing more these days on range and using 20mph now as my common reference / test / comparison speed.
    Yeah--anything above about 16 to 18 mph, and the wind-resistance begins to build exponentially.

    Unless piloting some ultra-aerodynamic bubble-bike, we're really only turning battery energy into headwind above about 20mph.

    I know it's not so easy to slow down these days--it's sort-of a rush-rush-rush-rush-hurry-up world. But there's definitely advantages to slowing down--not just the obvious boost to effective battery-range.

    I find I am more fully immersed in the riding experience--more able to enjoy the scenery, etc. if the wind in my ears isn't deafening--and if I'm not having to squint into a storm-force blast of wind (and dust and bugs)...  In fact, find I rarely get bugs in my mouth or eyes at all if I'm keeping at or below 15mph or so... Also, I find that I actually have more physical endurance--so that even though riding a little more slowly, I can actually cover a greater distance. Because it's less stressfully exhausting, the slower I go, the less I have to "ride my reflexes"--so that means I can relax more; and can therefore go considerably further on any given day. Reductions in speed benefit range--in terms of both battery and body...

    Sure--admittedly--more often than not, I'm buzzing around closer to the 20mph end of things when I'm just commuting. But if I want to take a longer trip, it's incredible what a two or three mile-per-hour reduction in speed can do to my effective range...

    I'm certain my 4KW Cyclone will propel my bakfiets well over 30MPH--and whenever I plop the DD front-wheel hub-motors on it, its potential top speed might be faster still--I've really no idea. But on that machine, fast genuinely isn't fun--it's terrifying! I've currently no machines which I'd feel safe riding on at 30 mph sustained.

    But certainly, on the right machine, fast is fun--no doubt about it. And I'm not here to rain on anyone's parade (though if it does rain--it's a good idea to slow down--it's not just your own controllability, it's the visibily of other drivers you gotta take into account--but I digress)... So--yeah... For all you speed-demons--hey, go for it! I guess for me, if I really want to go faster on e-transport, I'll just take the NS train. It too is electric (powered by 100% wind-energy), and hits 140+kph between stops!  :-)

    I'm enjoying reading the discussion and seeing folks' experiences and strategies...  

    Best of luck with your projects, everybody!

    Take care,

    Tklop
    Last edited by tklop; 10-27-2019, 10:37 AM.

  • Gr8fun
    replied
    My bike came with 700 c 28 tores the largest i could get in the frame was 32. I ditched the the rim and went to 27.5 (650b?) A schwalbe energizer plus with taller sidewall and 2.00 inch tire made the handling much better . no sacrifice in speed. Full rim- tire diameter even the same. Comfort increases with lower pressure, but extreme efficincy loss. Keep pressure up.
    Range has been most affected by adding a fairing ( solar) reduced wind resistance by 3 watt hours per mile at 20 mph. And top speed by ? Over 36 on bbso2.
    Never charge.
    Last edited by Gr8fun; 10-27-2019, 05:28 PM.

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  • ncmired
    replied
    1/4 inch wider I'd think would soften the ride, depending a little on the pressure. Dunno about the top speed - hard to discern what a tire will do.

    Like me I guess, my bikes are facing old age. I'm finding it hard to wring out 30mph anymore and I don't know why (probably drag).

    'm focusing more these days on range and using 20mph now as my common reference / test / comparison speed.
    Last edited by ncmired; 10-27-2019, 08:35 AM.

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  • cupid
    replied
    Originally posted by ncrkd View Post

    In my case, a BBSHD pulling a 42 / 18 front / rear gear ratio, 1:1 via the IGH through 700C-38 tires works out to 55 gear-inches - with this setup I think the motor RPM is maxed out on level ground, at 32-33MPH. Being just at the peak motor RPM means that the bike maintains speed pretty well on slight inclines. I don't know how well it would pull another 10 gear-inches.

    And, no, I can't pedal anywhere near that fast (~140-150 cadence) so, it's all motor.

    Unfortunately mass (~380lbs), air resistance (upright barn-door), and mechanical drag (IGH) are all putting a hurt on the speed.
    My bike came with 700C 38mm tires; I am thinking about getting wider 700 x 45 mm tires. How would that effect the top speed? Probably it won't affect max speed but I would just get better rider comfort and tracking right?

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  • AZguy
    replied
    42 / 18 ≈ 2.33 vs. [mine at] 39 / 11 ≈ 3.55 so my max speed limited by motor RPM would be ~1.52x yours (i.e. you have ~66% my maximum). So let's say I can go 40mph you'd be limited to ~26.3mph

    I'm pretty certain you'll need a higher ratio to exceed 30mph...

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  • bootaggie
    replied
    Originally posted by ncrkd View Post

    So, a 42 front - what top speed do you get on the 17 tooth rear sprocket (4th smallest) on level ground?

    P.S. yeah, it's gonna be a little too cold to perform speed tests right now ;-)
    About 25. Just starting to get little cold in Texas

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  • ncmired
    replied
    Originally posted by bootaggie View Post

    I am tuning the leakiest bling ring on the Roam 2. The tires are 700x38
    So, a 42 front - what top speed do you get on the 17 tooth rear sprocket (4th smallest) on level ground?

    P.S. yeah, it's gonna be a little too cold to perform speed tests right now ;-)
    Last edited by ncmired; 12-31-2017, 03:06 PM.

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  • bootaggie
    replied
    Originally posted by Poco Askew View Post
    What is your high gearing and tire size?
    I am tuning the bling ring on the Roam 2. The tires are 700x38
    Last edited by bootaggie; 12-31-2017, 04:05 PM.

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  • ncmired
    replied
    Originally posted by Poco Askew View Post
    What is your high gearing and tire size?
    In my case, a BBSHD pulling a 42 / 18 front / rear gear ratio, 1:1 via the IGH through 700C-38 tires works out to 55 gear-inches - with this setup I think the motor RPM is maxed out on level ground, at 32-33MPH. Being just at the peak motor RPM means that the bike maintains speed pretty well on slight inclines. I don't know how well it would pull another 10 gear-inches.

    And, no, I can't pedal anywhere near that fast (~140-150 cadence) so, it's all motor.

    Unfortunately mass (~380lbs), air resistance (upright barn-door), and mechanical drag (IGH) are all putting a hurt on the speed.
    Last edited by ncmired; 12-31-2017, 02:47 PM.

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  • Poco Askew
    replied
    What is your high gearing and tire size?

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  • bootaggie
    replied
    What kind of suggestions do you have with configuring the controller?

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  • AZguy
    commented on 's reply
    Have you fiddled with the controller parameters?

  • AZguy
    commented on 's reply
    With the exception of hubs mine is terrible on the rest

  • ncmired
    replied
    Reduce mass, air resistance, and mechanical drag (tires, hubs, brakes) where possible.

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