how much power can a regular bicycle frame endour?
- Thread starter vex_zg
- Start date
Chalo
100 TW
More than you can. More than would be pleasant or safe to ride.
If you want a motorcycle, use a motorcycle.
If you want a motorcycle, use a motorcycle.
Chalo said:
I don't want a motorcycle, never had one and I don't feel comfortable going more than some 40-50km/h. But I do like torque, for going uphill offroad. Been riding MTB my whole life on all terrain configurations.
My specific dilemma is can a XC/AM Full suspension Frame such as Cube AMS 130 take some 3-4kw and corresponding torque from mxus 3k @ 60A/72V)?
Will something around where torque arms grab the frame get warped or broken from the torque?
dogman dan
1 PW
Pictures of the rear dropouts of your bike would help a lot. Or at least, a link to the exact frame you have. It's not like I have one of everything on earth in my garage.
http://www.bike-magazin.de/uploads/tx_saltnews/fb/fb615b897960bffe92c2dab7ab1c4162b5cfc5b0.jpg
That link could be your bike, but does not show the rear in much detail. It does look a bit like the rear of that particular version is not particularly strong and beefy looking.
There is not any particular limit to how much power a frame can handle. But its an alloy frame, which means it really needs two good steel torque arms to support the aluminum.
The problem usually is, how well does that particular frames dropouts adapt to receiving a torque arm. Grins universal rear torque arm should fit nearly any bike. But once you start looking at really big torque, like 3000w on up, its a lot better to start making your own, much thicker, much stronger TA's. At that point, a big flat thick aluminum plate for a dropout helps a lot. Or, better still, removable steel dropouts on the frame, that can be removed, and a custom plate bolted on. The custom plate might then be a clamp on type dropout.
I don't hesitate a bit to run 3000w on this. Another one just like it on the other side. Just a nice flat plate on the frame allows easy bolt on use of a standard torque arm on both sides.
For another bike I have, I had to use a home made TA, similar to grins universal TA. On that bike, I just run 1000w, but would be ok with 2000w.
http://www.bike-magazin.de/uploads/tx_saltnews/fb/fb615b897960bffe92c2dab7ab1c4162b5cfc5b0.jpg
That link could be your bike, but does not show the rear in much detail. It does look a bit like the rear of that particular version is not particularly strong and beefy looking.
There is not any particular limit to how much power a frame can handle. But its an alloy frame, which means it really needs two good steel torque arms to support the aluminum.
The problem usually is, how well does that particular frames dropouts adapt to receiving a torque arm. Grins universal rear torque arm should fit nearly any bike. But once you start looking at really big torque, like 3000w on up, its a lot better to start making your own, much thicker, much stronger TA's. At that point, a big flat thick aluminum plate for a dropout helps a lot. Or, better still, removable steel dropouts on the frame, that can be removed, and a custom plate bolted on. The custom plate might then be a clamp on type dropout.
I don't hesitate a bit to run 3000w on this. Another one just like it on the other side. Just a nice flat plate on the frame allows easy bolt on use of a standard torque arm on both sides.
For another bike I have, I had to use a home made TA, similar to grins universal TA. On that bike, I just run 1000w, but would be ok with 2000w.
Chalo
100 TW
Your best bet might be to find a frame with sliding dropouts, and have someone make you custom torque plates to fit the slots. If you don't need length adjustability, putting a mounting bolt at each end of the slot is the strongest arrangement.
Thanks to both. These are the dropouts.
http://www.thebikelist.co.uk/images/models/Cube/2013/ams-130-pro/7454200-d09-ams-130-pro-black-grey-blue_mini.jpg
http://www.njuskalo.hr/image-w920x690/mtb-bicikli/cube-ams-130-pro-18-2013-slika-81427667.jpg
I have some torque arms and I can find a way to secure them to the frame.
But I am actually asking your opinion about: Provided that 2 torque arms are used and secured well to the axle and the frame, do you think that then a XC/AM MTB frame can take the torque that 3-4kw will generate? I am not asking about the dropouts only, but the frame itself.
This is the frame
https://i.ebayimg.com/00/s/NTc2WDEwMjQ=/z/-xwAAOSwCGVX3uIN/$_86.JPG
http://www.thebikelist.co.uk/images/models/Cube/2013/ams-130-pro/7454200-d09-ams-130-pro-black-grey-blue_mini.jpg
http://www.njuskalo.hr/image-w920x690/mtb-bicikli/cube-ams-130-pro-18-2013-slika-81427667.jpg
I have some torque arms and I can find a way to secure them to the frame.
But I am actually asking your opinion about: Provided that 2 torque arms are used and secured well to the axle and the frame, do you think that then a XC/AM MTB frame can take the torque that 3-4kw will generate? I am not asking about the dropouts only, but the frame itself.
This is the frame
https://i.ebayimg.com/00/s/NTc2WDEwMjQ=/z/-xwAAOSwCGVX3uIN/$_86.JPG
Chalo
100 TW
vex_zg said:
The torque from a hub motor is resolved between the axle and the torque arm. If you do a good job of locking the axle in place, torque isn't something you should worry about affecting anything else. There's a certain amount of thrust at the wheel, but the forces won't exceed what you get from things like hard braking and bunny hopping.
Inertial loads on the dropouts, from having a big heavy hub hard-mounted there, are probably the largest and most unusual dynamic forces your frame will experience. Those forces would result in accelerated wear on the suspension pivots, especially those closest to the axle.
dogman dan
1 PW
Id agree with all that. two well installed torque arms can handle 2000w easy. 4000w,, well, keep an eye on them. and bear in mind regen loosens your nuts.
The frame itself can handle the big hub motor on it,, but like he said, it won't wear slow that way, shocks and pivots will be taking a beating, whatever wattage you run. But if you run fast, the beating just increases. Sometimes we see a broken frame here on the sphere, but its not happening to everybody.
Just don't go into this thinking you won't wear out bikes fast, putting big motors on them. they will wear out fast, compared to pedal only. So figure that bike is going to wear out, but not in just one season. I'm just saying 10 years from now it will surely be beat to death.
The frame itself can handle the big hub motor on it,, but like he said, it won't wear slow that way, shocks and pivots will be taking a beating, whatever wattage you run. But if you run fast, the beating just increases. Sometimes we see a broken frame here on the sphere, but its not happening to everybody.
Just don't go into this thinking you won't wear out bikes fast, putting big motors on them. they will wear out fast, compared to pedal only. So figure that bike is going to wear out, but not in just one season. I'm just saying 10 years from now it will surely be beat to death.
dropout view good here
http://i.ebayimg.com/images/g/IQ8AAOSw6ShZUDBJ/s-l1600.jpg
Thanks to both. I don't plan to use regen just yet, but I understand it doubles the stress on bolts securing axle and torque arms.
With most of bicycle frames running 27.5 and 29 wheels now, there is little space left in the frame for a triangle pack, you basically need a 26" frame if you want full suspension. I don't want a dedicated ebike frame because those look too much like motorcycle and draw more attention.
http://i.ebayimg.com/images/g/IQ8AAOSw6ShZUDBJ/s-l1600.jpg
Thanks to both. I don't plan to use regen just yet, but I understand it doubles the stress on bolts securing axle and torque arms.
With most of bicycle frames running 27.5 and 29 wheels now, there is little space left in the frame for a triangle pack, you basically need a 26" frame if you want full suspension. I don't want a dedicated ebike frame because those look too much like motorcycle and draw more attention.
dogman dan
1 PW
The lightening holes do look scary, but I still think you can put a motor on that. I'm not sure I'd put my 25 pound old crystalyte on it, and run 3000w though. But a lighter, 16 pound motor should work fine, and run 1500-2000w. That TA will attach at the seat stay, which looks strong enough to me.
You mentioned standing out,, running more than 1000w always stands out, if you let it out. People see you going 35-40 mph, and look at you like this.
keep it below 30 mph, which you get with 1000w, and you barely get noticed.
You mentioned standing out,, running more than 1000w always stands out, if you let it out. People see you going 35-40 mph, and look at you like this.
keep it below 30 mph, which you get with 1000w, and you barely get noticed.Similar threads
