breaking 35 mph?

Just want to get some thoughts. What types of setups to people run that can cruise 35 mph? I can do 30 now on flat ground, but if I could cruise comfortably at 35 I actually would feel safer, since keeping up with traffic would be possible. Now, I have to stay off main streets when riding to work b/c rush hour traffic is just too scary and people have no mercy on cyclists and pass by uncomfortably close.

I'm running a 9-c 2806 motor, 25A infineon IRFB4110 controller and 12S RC lipo. It seems like from playing with the ebikes.ca simulator the best way to get the speed I want is to go to 18S 72V. True? Running a 2805 motor at 48V doesn't seem to quite get to the speed I would like.

Another thing, my bike is a rigid english 3-speed. Great commuter bike but might get a little sketchy at such high speeds. Perhaps a totally new build is in order one day. Anyone doing these speeds on a rigid frame?

Many of us have built faster bikes on the Mongoose Blackcombe bike. It was around $300 at Walmart. Full suspension, steel rear dropouts, nice rigid frame. My cruising speed with a high sped Mac and Lyen controller at 48v is around 35 mph.

yopappamon said:

Many of us have built faster bikes on the Mongoose Blackcombe bike. It was around $300 at Walmart. Full suspension, steel rear dropouts, nice rigid frame. My cruising speed with a high sped Mac and Lyen controller at 48v is around 35 mph.

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What 'T' mac motor are you using to get that speed may I ask? 6, 7, 8?

Kudos

Many are doing faster on rigid frames. It is safe if the streets are nice and the bike has good brakes and tires.
just raise your voltage adding another 6s and you will be much faster.
Best frames for high speed are DH racing bikes, that you can find used off season for a good price.
DH and Freeride bikes have good suspension and brakes already, and a stiff frame that can ride hard and fast very nicely.

Well, personally I start wanting suspension at about 25 mph, or even less. That ruined lower back.

On your current motor, 18s should get you 35mph. It need only be a 20 amp 72v controller, if you want to be sure you don't melt down the motor on longer rides. I'd say that's the best route for your to try.

I've found with 9c motors, a 72v 40 amp is really fun, but the risk of melting down if your battery capacity is big enough to last is definitely there. But when I run my 72v 20 amp lyens, I never have to worry. On a 2807, the 40 amp controller will go 40 briefly on 20s. With the 20 amp, you max out at about 35. Your faster wind should still hit 35 and cruise there all day on 18s.

Re the blackcomb, I think they finally sold em out at WM. But there are some fairly decent Genesis bikes, that also have a better than usual rear suspension setup for a less than $200 bike. They also can fit a few batteries in the frame.

74V on HS3540 with Lyen 12FET/18FET controller on Full Suspension will make 35mph ride really comfortable and very low risk of burning out your motor.

Just make sure you don't go that speed in > 110 degree F condition for a long time.

I ride my rig everyday at 33-37mph speed @ 1.3KW - 2KW for about 8miles everyday. No problems.

35mph on rigid frame is possible if the streets you ride on are almost always in perfect condition. Sadly, this is hardly the case, so I would go with full suspension. Anything > 25mph on rigid frame is really hard on the you the frame and the hub motor.

andrew.box said:

Just want to get some thoughts. What types of setups to people run that can cruise 35 mph? I can do 30 now on flat ground, but if I could cruise comfortably at 35 I actually would feel safer, since keeping up with traffic would be possible. Now, I have to stay off main streets when riding to work b/c rush hour traffic is just too scary and people have no mercy on cyclists and pass by uncomfortably close.

I'm running a 9-c 2806 motor, 25A infineon IRFB4110 controller and 12S RC lipo. It seems like from playing with the ebikes.ca simulator the best way to get the speed I want is to go to 18S 72V. True? Running a 2805 motor at 48V doesn't seem to quite get to the speed I would like.

Another thing, my bike is a rigid english 3-speed. Great commuter bike but might get a little sketchy at such high speeds. Perhaps a totally new build is in order one day. Anyone doing these speeds on a rigid frame?

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Andrew - I have a recumbent bike, rigid frame. I have very similar equipment to yours, excepting my motor is a 'slower wind". I have the same controller (modded to 40A) and 18S lipo. I second what dogman and mvly are telling you regarding speed and motor power, no need for me to repeat their comments.

I've been able to go as fast as 41mph with 24S. This was on a perfect road, bright, nice day and light traffic. Tires were Schwalbe Marathon at full inflation pressure. While the bike itself didn't seem to have any problems with the speed, I felt less comfortable running it that fast and backed it back down to 18S and 31mph on a 9c 2810 rear DD motor.

I like your build and I think 35mph is do-able. I'd suggest the fattest tires you can get under your fenders (I use 28c-35c thickness Kenda tires that can go up to 100psi if needed). I think I see in your picture that you've already got a suspension seat? If not, I'd add that, and maybe, possibly, a suspension seatpost.

I'd start worrying about the brakes at over 30mph too. I have big V-brakes on my machine at slowing down from 40 mph was a lot more difficult than slowing down from 30mph. I could tell the high speed was heating up the brake pads more and making them soft. In your case, I'd recommend having a regen switch to help with braking, either in the brake levers or a throttle with the regen button. You will need two good torque arms on your front motor.

One option is that if you realize you need some shock absorption at 35mph and above, you could swap out the front forks for suspension forks. That would also give you the option of a disc brake.

JKB

If you can do 30mph on your current setup with 12s, then going to 15s and maybe shunt modding your current controller for 30A+ should get you 35mph. 18s will definitely get you there but will require a controller that can take the higher voltage, so if the one you have will support 18s, then that's probably the best ticket.

A 5mph speed increase sounds like nothing big, but it is.

It takes around 1000 watts to go 30mph. It takes around 1600 watts to hit 35mph. A 60% increase in power. thats 60 % more power going through the motor, but also 60% more stress on things like tires, wheels, bearings, brakes, the frame, ect.

Thats more abuse that I would ever give to a wallyworld bike. You need something stronger for sustained speeds at those power levels.

wesnewell said:

If you can do 30mph on your current setup with 12s, then going to 15s and maybe shunt modding your current controller for 30A+ should get you 35mph. 18s will definitely get you there but will require a controller that can take the higher voltage, so if the one you have will support 18s, then that's probably the best ticket.

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Wes - good point about sharing info on how to mod the battery to push faster. You did a better job of hitting on his question than I did.

I run 18S and use an 18S-capable bulk charger. I like staying with a whole multiple of 6s: it makes balance charging and bulk charging practical and helps fight the cost increase of going to that high a voltage. I balance charge with a little 6S unit and configure my pack in parallel first, then serial, so I can get at all the balance wires.

I have the same controller you do, modded for 40A. It'll do 18S no problem, all day long on a road bike. I've experimented with higher voltage (next-up multiple of 6S, 24S), but you void the warranty if you go beyond 18S. My controller is bolted underneath an aluminum bolt-on rear rack and I've never had any heat problems. Mainly because I go for efficiency: I rarely go over 1200-1500 watts and it's unusual for me to reach 2000 watts, although cruising at 40 with 24S will get you there: I can see 2200-2300 watts in a hurry.

One thing I was surprised by is that raising the voltage doesn't seem to help with efficiency. It MIGHT be more efficient, but the losses due to air resistance and the "to the cubed" demands of going incrementally faster make any efficiency gains invisible. That sensibility is reflected in the sim: higher voltage just "elevates" the curves, it doesn't change the shape so much.

It's hard to understand what you are told here on E-S without experiencing it yourself. Take the advice, but not as gospel - do your own experimentation and post to E-S about what you find. You might solve different problems in a unique way that no one else here has done. That's why all of us tend to build so many variants of ebike: we're all pursuing our own priorities and dealing with the unique stress effects to get in that direction.

JKB

andrew.box said:

Just want to get some thoughts. What types of setups to people run that can cruise 35 mph? I can do 30 now on flat ground, but if I could cruise comfortably at 35 I actually would feel safer, since keeping up with traffic would be possible. Now, I have to stay off main streets when riding to work b/c rush hour traffic is just too scary and people have no mercy on cyclists and pass by uncomfortably close.

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It seems like everyone who builds an ebike has to answer this question for themselves: the question of going 35mph....or not? That speed range, 30-35mph, is an important speed range for exactly the reasons you mention and in a lot of situations a 30-35mph cruise capability makes an ebike time-competitive with an automobile, since most urban speed limits are 35mph....

The 9C in a 26" wheel can do a little over 35mph, but not for too long. Maybe for short sprints!

Yes, energy usage goes way up too. When you hit 40mph, you are in the 2000W zone. These motors are meant to do 500W-750W continuous, at most.

Heat will build up pretty bad. You could fry the motor in the summer doing this. If you have a hilly terrain, then you could melt it down pretty bad running 2000W continuous. Install a temp sensor if you bump this motor up to higher voltage and when you hit 100C-125C, know that it's time to back off the throttle!

since most urban speed limits are 35mph....

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That would be fine if the dumbshits could read!.

I can run 35 in a 35 speed limit, the problem is the other guy doesn't think it's fast enough. they blow by at 45/50mph all the time.

35 is fast enough for me. Full suspension, big tires makes it comfortable but not safe here.
15s4p Lipo, Mac 8t, 26 x2.4 tires, 8" hydro disc frt & rear, BlackComb or Tech-4. Both are great rides.

Dan

15s will go on that controller, but 8 v more will not produce 5 mph. Bet you'd see 32-33 though.

I pull 1500w going 35 for sure, more on a bike with panniers. So supposing you had the voltage to spin the motor that fast on 15s lipo, a 30 amp controller would get you to 1500-1600w.

Cheap to try it, a blob of solder on the shunt, and a 2s lipo pack.

Thanks for all the feedback, I have added paniers since taking my profile photo, but I'm getting the 30 mph with paniers. Going to 18S sounds like a decent option if I watch the motor temp on hot days, although the motor simulator shows time to overheat as "never" with the 25A controller. It sucks that I just built my 12S pack though and I actually like how it turned out, so going 18S would mean breaking it back down and rebuilding everything, not to mention soldering up a bunch of new series/parallel connectors which was a pain. And getting a new Meanwell for charging. But then again, now would be the time to add cells since they haven't been through more than 1 or 2 cycles.

Just realized the charger situation might be an easy thing to upgrade, just add a 24V Meanwell. I have the NES-100-50 now (2A, 50V, 100W version). That means I can add the 2A 24V version in series, correct (NES-50-24)?

dogman said:

15s will go on that controller, but 8 v more will not produce 5 mph. Bet you'd see 32-33 though.

I pull 1500w going 35 for sure, more on a bike with panniers. So supposing you had the voltage to spin the motor that fast on 15s lipo, a 30 amp controller would get you to 1500-1600w.

Cheap to try it, a blob of solder on the shunt, and a 2s lipo pack.

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Uh, you're cut off. Close the bar. Going from 12s to 15s is more like 12V. Sim says it will do 36mph @40A.

I don't think you guys noticed, but this guy has a FRONT motor.

Be careful raising the power, you want to have good torque arms up front and steel forks. I myself am running 1700watts on a front 9c 2810, steel forks and an ebikekit torque arm. So far so good, but I do plan to add a clamping torque on the other side to be safe.

Just my 2 cents here

I think that 30mph on that bike is more than fast enough, to get your speed up and over 35mph it requires a significant increase in power and trust me cars will still pass you even when you are doing 35mph! it makes no difference cars see a bike and they think overtake...overtake... its programmed in to their heads.

You also need to consider the brakes on the bike too, are they really up to it? does the bike handle well generally? does it corner OK? it's front wheel drive too so this will add in an extra risk factor especially in the wet and on loose road surfaces.

My opinion is 30mph on an ebike is fast enough really and you are already a lot safer than conventional cyclists would be because the passing speed of the cars is only a few mph, keep it as it is

Riding at 35mph and a top speed of 35mph are 2 totally different things. You need to explain exactly what you want, what kind of loads your drive system has to push including weight, elevation changes, quality of roads, etc. to get quality advice. eg The 35-40mph range is my typical cruising speed on good roads with all of my ebikes, but they will all go at least 50mph, and my latest system will do 65mph with a fresh battery and hold 55mph up a 6% grade.

Also, if you cruise at 30 now, what makes you think just 5 mph more will satisfy you. If your system is already operating at its limits to get to 30, then doing a whole new build for just a 17% increase in performance seems silly. OTOH if you want a useful 35mph, which is 35 up slight grades and into headwinds, and passing power to safely get around a dumptruck doing 34 that's pelting you with sand. Do yourself a favor and build a bike that goes the speed you want in all sorts of conditions, instead of another bike whose throttle might as well be just an on-off switch.

John

Heh Heh, You got it right Wes. I was flying on sudafed yesterday, trying to shake off a sinus infection. Wonder what other stupid shit I posted yesterday?

Yep, 12.6v more would add just about 4 mph, getting him real close with that faster winding motor. For sure, he'd see 33-34 mph. Remember, when I talk speed, I mean real world speed, measured both ways on a test run. So my 50 mph bike is called a 47 mph bike.

He'd be a bit faster on 40 amps as well. But if he ups his voltage on his current controller, he'll have 25 amps. But the watts to do it will be there, about 1600w.

Definitely there is a difference between hitting 35 mph, and cruising 35 mph for a long ride. Personally, I prefer a slower ride if it's long. I like to be able to look at the view since we have one here, relax, and enjoy the ride. At 30 mph, all I do is scan the street for glass and metal objects, and watch desperately for cars pulling out of cross streets and parking lots. Not a relaxing ride.

Front hub is not an issue yet. Up to 2000w is not particularly risky. But you will start grinding away the front tire above 1000w. Good torque arms are of course mandatory.

18s with a 20 amp 72v controller, your overheat time will pretty much be never. If I don't overheat where I live, you won't either. It's with a 40 amp controller that you start needing to really keep an eye on motor melt.

You can hold 30mph, but you think an extra 5mph would make you feel safe in traffic? Think again. However fast you go, drivers will see a bike and immediately pass you, because that's their knee-jerk reaction. Go 50mph, and they'll burn past you at 60. You won't feel, or be, any safer. The faster you go, in fact, the less safe you'll be.

Get used to sharing the road. Get used to going slower than others would like to go. Wear your imaginary VW Microbus if it helps. Not everything on the road has to go at the same speed.

If you didn't have some understanding of "less is more", you wouldn't be on an electric bicycle. So use your understanding of "less is more" in this case.

Chalo

veloman said:

I don't think you guys noticed, but this guy has a FRONT motor.

Be careful raising the power, you want to have good torque arms up front and steel forks. I myself am running 1700watts on a front 9c 2810, steel forks and an ebikekit torque arm. So far so good, but I do plan to add a clamping torque on the other side to be safe.

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100% right...

The need for dual torque arms up front goes up with increasing power.
Also: I expect 35mph is as fast as you want to go, ever, on a non-suspended bike.

jkbrigman said:

veloman said:

I don't think you guys noticed, but this guy has a FRONT motor.

Be careful raising the power, you want to have good torque arms up front and steel forks. I myself am running 1700watts on a front 9c 2810, steel forks and an ebikekit torque arm. So far so good, but I do plan to add a clamping torque on the other side to be safe.

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100% right...

The need for dual torque arms up front goes up with increasing power.
Also: I expect 35mph is as fast as you want to go, ever, on a non-suspended bike.

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I wouldn't want to hit an unexpected pothole at 35mph without some type of suspension. That would be the start of another similarly name thread: 'breaking limbs at 35mph'

Manhole covers are quite a thrill, on a no suspension bike at 47 mph. I don't recomend a pothole.

Definitely two torque arms on a front hub with higher power. And C washers for most forks.

Chalo is very right about one thing, Car sees a bike, they think they have plenty of time to pull out in front of you.

Then along you come at 35 mph. Good brakes will be meaninless at that point. You better be able to do a powersiding turn on a dime. With a front hub too. 8) Oh, you'll still hit the car, but the idea is to make it a glancing side blow, instead of stuffing your head through the side window.