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    #46
    Originally posted by Steve-- View Post

    lmao, that's a good one. Although... A sheet of plywood set horizontal actually is pretty damn aerodynamic :)
    I glad my post on this old thread is still providing amusement. I just dusted off that bike and reworked it for a trip to Florida. There is one county down there that is anti ebike and this bike looks more normal than my other bikes.

    Comment


      #47
      Which county hates the noise of E bikes?

      Comment


        #48
        Originally posted by Retrorockit View Post
        Which county hates the noise of E bikes?
        I wouldn't say it was the noise but just the presents of the Ebikes. There is one particular trail that is close to my daughters that I was hassled on. It is the Flatwoods Trail in Hillsboro county.

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        A few yards beyond this you get this sign.

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        I was riding my Electra fat bike which is quite big and I wear a full face Bell bicycle helmet. The ranger who went out of his way to chase me down might have thought it was a motorcycle. He was embarrassed when I pulled off my helmet and he saw a grey beard but he had already put his foot in his mouth and couldn't back out then. We argued for a while. No shouting though. He kept coming back to the no motorized vehicles while I corrected with pedal assist.




        This park has a lot of off road trails I would like to try but I think they would frown on my enduro.


        Comment


        • 73Eldo
          73Eldo commented
          Editing a comment
          You would have to see how the state defines motor vehicle for the one sign but the no e-bike kinda more specific.

        • Retrorockit
          Retrorockit commented
          Editing a comment
          The thing about Florida is there are lots of parks run by lots of different agencies with lots of different rules and enforcement. I have near my house City parks, County parks, and State parks. Some are equestrian only, some have separate horse and "multi use" trails, Others allow MTBs on horse trails.Some areas say no bikes or skateboards but nobody cares because they're connected to the bike trails anyway. E bikes are mostly under the radar here.One problem in my area is the county put in miles of connecting bike paths, but the cities, and even neighborhoods change the zoning to restrict use or access to them.Residents Only signs are common, but whether county, city, state, or neighborhood isn't specified.
          One thing that leads to conflict around here is cyclists who fail to yield to horse riders.I stop my bike and stand next to it so the horses see me as a person.
          Equestrians have money and land, and the political power that comes with it. They can get signs posted and zoning changed in many areas.

        • 73Eldo
          73Eldo commented
          Editing a comment
          I have heard about the resident thing too where they don't specify. Everyone resides somewhere so I can't imagine it has any actual legal meaning. This summer I found a cool paved path through the woods which when linked with some parking lots makes a nice bypass of some busy road intersections for connecting some trail systems. It appears to be part of a 'cooperate campus' that currently appears vacant and was a place for employees to maybe walk on breaks? I would imagine if they were active they would not want people passing through all the time but maybe the cars in the parking lots would make it just as bad as staying on the streets.

        #49
        Originally posted by MancaveAle View Post
        Greetings, just built my first one. BBSHD on fat bike. I seem to get a top speed of roughly 40-41 km/h. Anyway to increase that?
        You'll hear a lot of people say a lot of different things, and you can dink around with changing gear ratios, and tire diameters, and that certainly will help a little bit, but ultimately to increase speed you need to increase power or reduce weight/friction. It's a matter of physics.

        Comment


          #50
          Originally posted by Steve-- View Post

          You'll hear a lot of people say a lot of different things, and you can dink around with changing gear ratios, and tire diameters, and that certainly will help a little bit, but ultimately to increase speed you need to increase power or reduce weight/friction. It's a matter of physics.
          No offense meant however based on direct experience, I disagree with BBSHD going faster than 40kph needing to reduce weight or friction - do need to increase power and have the proper gearing

          I readily achieve closer to 55+kph on a very heavy BBSHD bike, with big fat knobbies (4.8") running 10-12psi (high rolling friction), carrying bags etc. (high air friction) as long as the ground is level - no tailwind or downhill required

          If not exceeding ~40kph it's more likely IMO to need a better tune on the parameters and maybe gearing - calculate the top speed based on the gears and top motor RPM (will vary on battery, mine readily does about 160rpm under light load), it's easy... Mine only needs to turn ~100rpm to do >50kph. Tires, weight, friction reduction, etc. - that's more likely looking in the wrong place

          This is the bike with relatively smooth tires, the ones I run now are much more aggressive:

          Click image for larger version

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          Comment


            #51
            Wind resistance is he biggest factor in top speed. Time trials road racing bikes will show you whats involved. Then just add power. Gear so that max power and max. speed happen at the same time.
            But stopping, handling, braking and visibility all take a hit in pursuit of speed.
            https://i.pinimg.com/originals/b8/2d...e79bbf8ad2.jpg
            At some point the rider themselves becomes the biggest factor.
            Last edited by Retrorockit; 01-14-2021, 08:19 AM.

            Comment


            • AZguy
              AZguy commented
              Editing a comment
              True that! It definitely takes the full ~1500W to get up above 30mph and taking 120-150W to maintain 10mph if I'm not pedaling sounds about right - I can achieve 10mph pedaling alone but for this old guy with one leg it's not fun for more than a few minutes...

            • Retrorockit
              Retrorockit commented
              Editing a comment
              I find the 17.5Ah battery useful more for allowing me to use the full power when needed than adding range. I think the normal 12Ah size would be restrictive for me in that way.

            • AZguy
              AZguy commented
              Editing a comment
              When I first started riding I couldn't pedal very hard or fast and my pedaling didn't contribute much and I rode a couple of mph faster on average than I do these days

              I had three batteries in the 11-14Ah range at the time (I have more now) so mounted two on the BBSHD bike and have more range than I can use

              Funny thing is now that I can pedal faster and harder and I contribute more significantly, if I back the speed down just a couple of mph my range nearly doubles and one battery, especially the 52V/14Ah, more than enough range (~50+mi typical)... even the smaller batteries are giving me 30-35+mi range these days... still nice to be able to carry a second battery, guarantee no range anxiety and if I feel like going faster than usual no worries...

            #52
            20mph headwinds off of the ocean are not uncommon here, and bridge construction/maintenance can force me to ride on roads with no bike lane, and a 45mph speed limit ( sometimes uphill at night).
            Sometimes I return home with a lot of battery left. Sometimes it's almost flat. They just installed a traffic circle on my ride. I'm finding that taking a lane, and holding your place in traffic is better than being passed by cars going into the roundabout which has no bike lane. 35mph speed limit makes full power necessary there. The obnoxious Niterider Lumina strobe really helps out when coming around the circle into oncoming traffic.

            Comment


              #53
              Originally posted by AZguy View Post

              No offense meant however based on direct experience, I disagree with BBSHD going faster than 40kph needing to reduce weight or friction - do need to increase power and have the proper gearing

              I readily achieve closer to 55+kph on a very heavy BBSHD bike, with big fat knobbies (4.8") running 10-12psi (high rolling friction), carrying bags etc. (high air friction) as long as the ground is level - no tailwind or downhill required

              If not exceeding ~40kph it's more likely IMO to need a better tune on the parameters and maybe gearing - calculate the top speed based on the gears and top motor RPM (will vary on battery, mine readily does about 160rpm under light load), it's easy... Mine only needs to turn ~100rpm to do >50kph. Tires, weight, friction reduction, etc. - that's more likely looking in the wrong place

              This is the bike with relatively smooth tires, the ones I run now are much more aggressive:

              Click image for larger version

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              I also do not intend any offense. However, mine was a general statement based on the laws of physics, and are not a matter of opinion.

              Comment


                #54
                Originally posted by AZguy View Post

                No offense meant however based on direct experience, I disagree with BBSHD going faster than 40kph needing to reduce weight or friction - do need to increase power and have the proper gearing

                I readily achieve closer to 55+kph on a very heavy BBSHD bike, with big fat knobbies (4.8") running 10-12psi (high rolling friction), carrying bags etc. (high air friction) as long as the ground is level - no tailwind or downhill required

                If not exceeding ~40kph it's more likely IMO to need a better tune on the parameters and maybe gearing - calculate the top speed based on the gears and top motor RPM (will vary on battery, mine readily does about 160rpm under light load), it's easy... Mine only needs to turn ~100rpm to do >50kph. Tires, weight, friction reduction, etc. - that's more likely looking in the wrong place

                This is the bike with relatively smooth tires, the ones I run now are much more aggressive:

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                P.S. Also, my comment wasn't specific to any particular speed, but rather about the laws of physics in general. I am a physicist by the way.

                Comment


                  #55
                  Originally posted by Steve-- View Post
                  P.S. Also, my comment wasn't specific to any particular speed, but rather about the laws of physics in general. I am a physicist by the way.
                  I understood you were talking in generalities and that's why I was trying not to come across combative (I guess I didn't do a good job), however the OP was asking a very specific question:

                  Originally posted by MancaveAle View Post
                  Greetings, just built my first one. BBSHD on fat bike. I seem to get a top speed of roughly 40-41 km/h. Anyway to increase that?
                  I'm trying to address that concern and was explaining that he should be able to go faster than that on his build and what the likely things he needs to do

                  More the engineering response vs. the theoretical I suppose

                  Comment


                    #56
                    The wide tires, knobby tread, and panniers are all going to hold that bike back as far as top speed goes. But if you're going camping in the woods that probably doesn't matter much.
                    One thing to think about is that at 30mph the wind speed of the bottom of the wheel is 0mph where it touches the ground. The top of the wheel on the other hand is going 60mph into the wind. Due to the 4x drag X air speed relationship this adds up to much more than 30mph average drag. In that configuration all you can do is throw more Watts at it. Lots of them.
                    Also the bikes most of us ride have wide blunt rims. Aerodynamically at the speeds involved here a round entry profile is about as good as any other shape. But to avoid turbulent drag the trailing edge is very important and should be tapered. Factor in frontal area and narrower and deeper rims would help top speed. Fewer, bladed spokes also at least on the non driven wheel.
                    Here's what mine looks like. It was a pedal bike I already owned and converted. I'm happy with the speed this combo provides.
                    https://electricbike.com/forum/filed...917&type=thumb
                    Last edited by Retrorockit; 01-17-2021, 08:50 AM.

                    Comment


                    • AZguy
                      AZguy commented
                      Editing a comment
                      As mentioned I have no problem going into the mid-30mph range (>50kph) on my pig with a stock (non-ludicrous) BBSHD consuming ~1500W from a 52V shark pack so I see no reason the OP can't exceed 40-41kph with proper gearing and parameter settings and expect that's where he needs to look

                    #57
                    Did we ever know more about the OP? 100 pound difference in the rider is huge especially at higher speeds or a positive grade. You put a big person on what is likely a fairly heavy bike with not the best components to start with you got a lot not going against you and the wind could be an issue. Open prairie, desert, or tundra along with being near large bodies of water can often mean there is always wind vs being in a more urban area were there are lots of things to block the wind.

                    Comment


                    • AZguy
                      AZguy commented
                      Editing a comment
                      Haha - you never know these days... I'm sort of middle of the road by today's standards, 80-85kg 180cm but the bike is very tall and I sit only somewhat leaned forward generally (my eyeballs are higher than most all the bikes I see on the multi-use paths) and I carry a lot of heavy stuff around

                      I agree and as I mentioned grades and winds have huge effect - From OP's post it sounds like he's never seeing much above 40-41kph and so I'm still thinking parameters and/or gearing

                    #58
                    My guess is it would take a 2500W controller and a large custom 60V battery to keep the Amps down and have some useful range. I have no personal experience with this.
                    Then the question of controlling a hardtail bike with large bouncy low pressure tires would become an issue. At some point one of the purpose built electric motorcycles would be more appropriate.

                    Comment


                    • AZguy
                      AZguy commented
                      Editing a comment
                      I'm with you - it's not practical to ride much more than 40kph (~25mph) on a BBSHD hardtail... range goes into the crapper and and for me at least it's just plain scary. It isn't unstable or anything like that and I've got plenty of time doing 150-200kph (~90-125mph) on motos so not really lack of juevos, but motos have so much more mass (5-10x!) and I'm wearing much better gear (all armored and moto helmet, leather gloves, etc.) on them and that was when I was a lot younger... even if the bicycle is loaded down with gear it's going to be significantly less than half my weight and it just doesn't feel "secure" at those speeds, the places I ride (never on street) are narrow with nearby obstacles, etc. and I really don't want to take spill even at 40kph... I'm already suffering enough from all the fights with gravity and speed where they won =]

                    • Retrorockit
                      Retrorockit commented
                      Editing a comment
                      We're already pushing pedal bike parts beyond their design limits with a BBSHD conversion. I run a "vintage" Downhilll wheelset and metallic disc brake pad setup on the street. It seems to be good enough for fast and flat use. But I'm not sure that there's much reserve capacity for heavier, faster, or more intensive use. The metallic brake pads I use fit the Avid BB7 cable brakes, and also the Avid Juicy hydraulics.They say don't use them for DH racing on the hydraulics. So some sort of thermal design limits are being approached on some disc brakes. This will only show up at the worst possible time!
                      The Schwalbe Big Ben Plus tires I'm running are 50kph rated and say "moped" on them in the bead area. But there's only so much you can do. Sometimes "juevos" are not the solution, they're the problem!

                    • AZguy
                      AZguy commented
                      Editing a comment
                      I run metallic too - they say you want organic on aluminum for downhill but there will always come a point where the fluid will boil and bye-bye braking... had this happen in my truck going down a serious set of switchbacks (White Mtns in NV) - was going slow but they'll heat up anyway if you are dissipating potential energy faster than they can shed it (there's my physics for the day =] )... had organic on the bike but the metallic last 5x as long and I don't do downhill often - metallic are supposedly better for short hard braking anyway which is more my style...

                      I've always said as long as the juevos aren't bigger than the brain you're likely ok... I've certainly come across plenty of moto guys where the opposite is true...

                    #59
                    The fluid on my bike will never boil. There isn't any. For my fast street riding where traction is good Avid BB7 mechanical discs are reliable and effective.
                    Here's how I decide when to switch to metallic brakes. Test your brakes as hard as you can. On flat ground that means full acceleration and repeated hard stops. Even heat up the brakes by dragging them under power ( this simulates a long downhill run without the danger). On a full speed stop the brakes should require high hand pressure at high speed, and you should need to modulate the pressure lower as the bike slows. If you find yourself adding pressure as the bike slows you have a lining issue. The resin in the pads is boiling onto the rotors and lubricating the brakes.
                    A fluid problem will show up as the brake levers sinking without an increase in pressure.
                    The metallic pad BB7 combo also eliminates the constant brake adjusting that happens with organics when run hard. Yes you can hear them.
                    With new organic pads you should heat them up when new, and let them cool. This produces a "heat treated" dry layer. As the pads wear this layer will work it's way down through the lining material.
                    Racers call this bedding in the pads, and they will prepare several sets this way so they never have "green" brake pads on the vehicle. ( Don't do this on drum brakes, it will glaze the linings.)
                    Any discussion of adding top speed to a heavy bike should begin with the brakes.
                    Last edited by Retrorockit; 01-19-2021, 08:26 AM.

                    Comment


                    • 73Eldo
                      73Eldo commented
                      Editing a comment
                      Do metallic pads have a different bedding process? I don't recall any of the videos I watched about bedding mention different pads using a different or not needing the process. Same thing with videos talking about the differences, they never mentioned bedding in their reviews.

                    • AZguy
                      AZguy commented
                      Editing a comment
                      Organics bed *much* faster than metallic and frankly you can get away without bedding at all without much if any issues

                      Metallic should be bedded and if you don't deliberately do it, they'll typically bed on their own after a considerably longer time and usually make a lot of noise (especially squealing) until bedded and will sometimes still be noisy after

                      A lot of shops avoid metallic because customers will complain about them being noisy although they sometimes get accused of going organic for cost (organic on steel are usually the cheapest option) and because they last much less time... I suppose their might be shops that do this but the owners I've talked to just don't like the customers complaining about the noise and they too often would end up replacing the metallics they installed with organic because the customer keeps bringing the bike back...

                    • Retrorockit
                      Retrorockit commented
                      Editing a comment
                      You can "get away' with a lot of things.I want the best performance from my brakes every time. I bed in my pads.
                      When going from organic to metallic pads residue form the old pads can lead to huge noise and grabbing issues. Clean rotors (abrasives are good for this) are a must. Bedding in will "just happen" over time. But if the first stop is a hard one they won't work as well as they should.
                      I worked as a mechanic in the truck rental industry. The thought of a customer, with perhaps no experience driving trucks,renting and loading up a vehicle with green brake pads seems like an accident waiting to happen. For me bedding in is part of the job. When bedding in you intentionally use the new brakes hard. The braking sucks. After the bedded brakes cooled the stopping is much better, and stays that way.
                      If you do the test I suggested with green organic pads they will almost always fail. If you bed them in they may be just fine.Organic pads vary greatly in composition. Some aren't much more than cardboard. There could be some organic pads that are very good. I just don't know which ones they are.

                    #60
                    After decades and a million miles on motos (the first few had cable pull drum brakes - yuck), and four bicycles with hydraulics, I'm in love with the feel and control of good hydraulics. I have cable pull discs on one bike but it's a beater/loaner so don't really care. On the e-bike beast I posted a photo of I did a beautiful stoppie for about fifty feet with the most gentle grease job landing a week or so ago and wouldn't even think of that on the cable pull brakes LOL - sure impressed a couple of my moto friends

                    Comment


                    • AZguy
                      AZguy commented
                      Editing a comment
                      Just for fun - getting plenty off-topic but best brakes I've ever owned and ridden on were these Brembos (after ditching the ABS)... amazing stopping power on pretty much any surface...



                      On this moto:


                    • Retrorockit
                      Retrorockit commented
                      Editing a comment
                      I have no experience with Hydros on a bicycle. I'm sure some of them are up to Ebike service, and some of them aren't. I was an early adopter of disc brakes and went with BB7 at the time. I converted that 2004 bike to BBSHD and needed bigger rear rotor (185mm/185mm) and metallic pads to make it work for me.
                      I'm sure the modulation is better with hydros. BB7 is considered much better than other mechanical discs in that regard, so generic mechanical discs may not be as good.
                      Aside from boiling fluid, there is the possibility of popping out a piston when working on/transporting the bike with a wheel removed. Also the need to adjust mine every few days means I'm down there checking the thickness of the pads every now and then.
                      The test I gave above will work to evaluate the heat rejection capacity of any brake, hydro or mech. I'm not saying one is better than the other, I'm just saying make sure your brakes can do what you need them to do. Newer bikes come with hydros, that's just the way it is.
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