Bicycle Frames suitable for eBike conversion?

[sonnetg]

Are there any good bicycle frames out there, which are good candidates for eBike conversion? I am in search for a bicycle frame which would have a strong rear dropout, and not require any additional torque arm installation. There are several frame options out there (like Flux Beta/NYX/Vector), but I am looking for a frame which looks more or less like a bicycle. I was actually interested in Sondors frame, if not for the "Fatty" version, it would have a been a great frame to customize.

Are there any regular bicycle frames built specifically for installing a high performing rear hub motor (+1000 watts)? I know this is a fruitless search, but doesn't hurt to ask..

Regards,

 

[Chalo]

First: You need to get used to the idea of having a torque arm for a 1000W bike. Dropouts, no matter how beefy, all have open-ended slots by design. That allows your flatted axle to pry the slot open. Even if the material is super strong and can recover its shape, the axle will be damaged by twisting into a sprung-open slot.

A torque arm can be much flimsier-looking than the dropout, but still be much more effective if it has a closed slot.

Have a look at single speed MTBs. They are made of chromoly more often than not, and their rear opening dropouts tend to be beefier than the run of the mill.

 

[mchlpeel]

Have a look at a specialized epic 2003-2008.
http://www.specialized.com/us/en/bikes/archive/2003/epic/epicdisc

Its a full susser that you can fit a triangle pack withing the frame without upsetting rear suspension.

You can pick one up in UK on Ebay for £250-£500

Its the frame im currently using to build a 1500W leaf motor with a large 14s 17.5 AH em3ev pack. Everything fits perfectly

Battey pack in traingle http://em3ev.com/store/index.php?route=product/product&path=35_51&product_id=123
18 fet Controller tywrapped under seat at the rear. http://em3ev.com/store/index.php?route=product/product&path=41_38&product_id=83
Motor in rear wheel does not get in the way of the suspension http://www.leafbike.com/products/e-bike-hub-motor/gearless-20-24-26-700c-28-inch/c-19/

I am using a torque arm that attaches to the rear IS disc brake mounts (literally just bolts on)
https://endless-sphere.com/forums/viewtopic.php?f=31&t=69073

I will put some pics when I have finalised cable routing etc.

Regualarly draw 3000W+ using that torque arm with no probs.

40mph top speed

Perfect.....

 

[Bluefang]

Something that looks like a bicycle Do you want suspension? If so the above is good ideas for suspension bikes otherwise I personally use alot of older cruiser or chopper frames and change out the front forks for cheap pitbike forks so i can use strong brakes without issue. Fyi if you get a old steel bike frame, a) its old and over built so will likely handle alot more weight then a cheap new alloy bike. b) It might have a 1" steerer which would allow you to use front forks from 90% of pitbikes which will come with hydraulic brakes that should work with 200mm bike discs. Or you can lace a pushbike rim to a motorbike hub and take full advantage of the braking power, or keep it simple and use full motorbike wheels

The attached cream bike is using 160 rotors and cable brakes but its a general idea with the purple bike. Both are cheap steel frames that get used and abused. Cream one with 2kw, purple with 14kw.
View attachment 1

 

[dogman dan]

Definitely get over the torque arm hang up.

One good criteria for choosing a frame is a large flat enough area around the axle. Like on this old Giant mtb. This allows using half of a cheap and easy to find front torque arm to bolt right to the frame. Drill one hole, bolt on. EASY.



But any bike can use Grins universal rear torque arm. Pricy, but cheap compared to new frame, or new controller.

If you want to have a bike that does not need any torque arm, then you can weld on any steel bike, to thicken the dropouts.

On my long cruiser, I welded the usual cheap bike steel derailleur hanger to the frame, then added material with the welder to the dropout, making it completely adequate for 1000w with no torque arm. When I go to 2000w in the next week or so, I'm just going to add a ta to the other side.

 

[999zip999]

They don't steal ugly bikes. And torque arms aren't ugly.

 

[sonnetg]

First: You need to get used to the idea of having a torque arm for a 1000W bike. Dropouts, no matter how beefy, all have open-ended slots by design. That allows your flatted axle to pry the slot open. Even if the material is super strong and can recover its shape, the axle will be damaged by twisting into a sprung-open slot.

A torque arm can be much flimsier-looking than the dropout, but still be much more effective if it has a closed slot.

Have a look at single speed MTBs. They are made of chromoly more often than not, and their rear opening dropouts tend to be beefier than the run of the mill.

Thank you. I am actually looking around for deals for a Surly frame, but I had no idea a single speed dropout would be stronger than multi-speed, but it's good to know. I will probably be installing a torque arm, but was hoping by now there would be plenty of bicycle frames ready to be converted to ebikes.

I currently use a 350 watt front geared front motor on my folding bike, and haven't installed any torque arm yet. I made sure the bolts are on real tight, but i do have a plan to install the arm.

 

[sonnetg]

Have a look at a specialized epic 2003-2008.
http://www.specialized.com/us/en/bikes/archive/2003/epic/epicdisc

Its a full susser that you can fit a triangle pack withing the frame without upsetting rear suspension.

You can pick one up in UK on Ebay for £250-£500

Its the frame im currently using to build a 1500W leaf motor with a large 14s 17.5 AH em3ev pack. Everything fits perfectly

Battey pack in traingle http://em3ev.com/store/index.php?route=product/product&path=35_51&product_id=123
18 fet Controller tywrapped under seat at the rear. http://em3ev.com/store/index.php?route=product/product&path=41_38&product_id=83
Motor in rear wheel does not get in the way of the suspension http://www.leafbike.com/products/e-bike-hub-motor/gearless-20-24-26-700c-28-inch/c-19/

I am using a torque arm that attaches to the rear IS disc brake mounts (literally just bolts on)
https://endless-sphere.com/forums/viewtopic.php?f=31&t=69073

I will put some pics when I have finalised cable routing etc.

Regualarly draw 3000W+ using that torque arm with no probs.

40mph top speed

Perfect.....

This is excellent information. I always pondered upon converting a Downhill MTB frame to an ebike, but losing the frame triangle was a no-go for me. Would a 12 mm axle fit the dropout? or would it require filing?

Would the torque arm would require drilling? or does it fit out of the box?

Thanks once again. A bike like this seems be exactly what I have in my mind.

Good luck with your project. Please do post some pics after you are done.

 

[amberwolf]

Thank you. I am actually looking around for deals for a Surly frame, but I had no idea a single speed dropout would be stronger than multi-speed, but it's good to know.

I used some BMX dropouts off a scrapped Mongoose frame to weld on to CrazyBike2, in place of the thin ones on the frame I built the backend from, and they've been working well for a long while now. They *have* been modified since then, but originally I made them into clamping dropouts and later cut that off cuz it got in my way, and stil haven't had issues, with no torque arms, 20" wheel, HS3548 w/40A 12FET controller, heavy bike, hard acceleration from every stop. I'm also using Nordlock washers on there, to keep the nuts tight, so that probably makes some difference too.

AFAICR they are 4mm+ thick, but not sure about that, might be a little thinner.

Either way, if the dropouts have any play in them letting the axle rock back and forth, you may have problems as the axle chews up the dropouts, if it's harder steel than they are, or if they're harder than the axle it'll chew a notch in it instead, and eventually it'll spin out.


But if you're not buildng your own frame, you might as well just use a torque arm or two on the frame that you prefer to ride.


FWIW there are a lot of ebike-specific frames out there (most of them as part of an ebike already), and most of them dont' seem to be any better than any cheap bicycle frame, from what we've seen here on ES.

I wouldn't expect to find any regular bicycle that's designed to convert to an ebike though--they don't have any reason to design or build them that way. If they did, they might as well just make them ebikes to start with and make more money off of them.

 

[sonnetg]

FWIW there are a lot of ebike-specific frames out there (most of them as part of an ebike already), and most of them dont' seem to be any better than any cheap bicycle frame, from what we've seen here on ES.

I wouldn't expect to find any regular bicycle that's designed to convert to an ebike though--they don't have any reason to design or build them that way. If they did, they might as well just make them ebikes to start with and make more money off of them.

Actually i was looking at some factory ebikes, and some of the manufacturers seem to have really given a thought regarding dropout design. The image below is of a Currie Izip dropout. Cheeep sondor bikes also have thicker dropout. It would be have been nice if these frames were sold separately.

Currie Izip Ultra:

Review: http://electricbikereport.com/wp-content/gallery/izip-ultra-electric-bike-review/dynamic/the-torque-sensor-tmm4-izip-ultra-electric-bike.jpg-nggid03229-ngg0dyn-540x406x100-00f0w010c010r110f110r010t010.jpg

Sondors: (not sure how much torque this can handle though, but certainly seems much stronger than most bicycles)

 

[sonnetg]

by the way...speaking of dropouts, which bike frame would fit a 12mm motor axle without having to file the dropout? Is it only DH frames which are 12mm dropouts?

 

[Chalo]

by the way...speaking of dropouts, which bike frame would fit a 12mm motor axle without having to file the dropout? Is it only DH frames which are 12mm dropouts?

Hub motors use 12mm or more commonly 14mm axle studs, but they have 10mm wide flats cut on them. You really don't want to use them in a wider than 10mm slot.

12mm DH frame ends are not "dropouts" per se; they are only round eyes for a skewer-like axle to pass through. What makes them basically incompatible with hub motors. The axle width is wrong, too.

 

[amberwolf]

Sondors: (not sure how much torque this can handle though, but certainly seems much stronger than most bicycles)
http://cdn.slashgear.com/wp-content/uploads/2015/02/storm-ebike-hands-on-sg-1-600x338.jpg

Without beign able to measure it, or knwo what hardness and type of metal it is, that basically looks like about half of the BMX frames I've chopped up for things (the other half usually have thin dropouts like some of the cheaper "old ten speed" (OTS) bikes often did.)

So you could use that as a comparison for the ones I used on CB2.

 

[mchlpeel]

Have a look at a specialized epic 2003-2008.
http://www.specialized.com/us/en/bikes/archive/2003/epic/epicdisc

Its a full susser that you can fit a triangle pack withing the frame without upsetting rear suspension.

You can pick one up in UK on Ebay for £250-£500

Its the frame im currently using to build a 1500W leaf motor with a large 14s 17.5 AH em3ev pack. Everything fits perfectly

Battey pack in traingle http://em3ev.com/store/index.php?route=product/product&path=35_51&product_id=123
18 fet Controller tywrapped under seat at the rear. http://em3ev.com/store/index.php?route=product/product&path=41_38&product_id=83
Motor in rear wheel does not get in the way of the suspension http://www.leafbike.com/products/e-bike-hub-motor/gearless-20-24-26-700c-28-inch/c-19/

I am using a torque arm that attaches to the rear IS disc brake mounts (literally just bolts on)
https://endless-sphere.com/forums/viewtopic.php?f=31&t=69073

I will put some pics when I have finalised cable routing etc.

Regualarly draw 3000W+ using that torque arm with no probs.

40mph top speed

Perfect.....

This is excellent information. I always pondered upon converting a Downhill MTB frame to an ebike, but losing the frame triangle was a no-go for me. Would a 12 mm axle fit the dropout? or would it require filing?

Would the torque arm would require drilling? or does it fit out of the box?

Thanks once again. A bike like this seems be exactly what I have in my mind.

Good luck with your project. Please do post some pics after you are done.

As Chalo said the axle may be 12 mm but the bit that actually slots into the drop out will usually be 10mm. This is a standard convention as most bicycle dropouts are 10mm wide.

The torque arm comes without the holes to clamp the open end but it comes with the holes to bolt straight on to the IS mount.
There is no need to clamp it as it is 10mm thick steel. Like I said I have pushed about 4kw through it from a standing start with no issues.
The torque arm slot is deliberately shipped with a slightly thinner dropout so you can file it for an exact fit. You need an exact fit for correct operation.
I didn't have a file but they are onle £2-5 in B&Q.

I should have the bike completed today or tomorrow so ill post pics for you

 

[sonnetg]

by the way...speaking of dropouts, which bike frame would fit a 12mm motor axle without having to file the dropout? Is it only DH frames which are 12mm dropouts?

Hub motors use 12mm or more commonly 14mm axle studs, but they have 10mm wide flats cut on them. You really don't want to use them in a wider than 10mm slot.

12mm DH frame ends are not "dropouts" per se; they are only round eyes for a skewer-like axle to pass through. What makes them basically incompatible with hub motors. The axle width is wrong, too.

Ok..so far I have installed two different motors. One fit perfectly on the 10 mm slot. The motor was a small 250 watt 8Fun geared motor. I also installed Ezee 500 watt geared motor, and i had to file the dropout to install it on my MTB. I haven't measured it, but the motor axle was slightly larger than 10 mm or my dropout was smaller than 10mm. I should have measured everything before i installed it. Got a bit carried away for sure. I need to install a torque arm for the 500 watt motor, but haven't gotten that far yet. Having issues aligning the disk rotor for now..

Here's a pic of both the motors:

8Fun 250 watt Geared Hub Motor

Ezee 500 watt Geared Hub motor

 

[sonnetg]

Things get even more puzzling when you have to chose between slot sizes:

http://www.ebay.com/itm/Multi-Angle-Torque-Arm-for-eBIke-Electric-Bike-Stainless-Steel-/111604943748?var=&hash=item19fc2c4b84:m:moXF7YruL31wBI2p4LyDkMQ

The above torque arm give you the option of 12mm or 14mm slot size, which seems to be non standard size for most bicycles. :|

 

[sonnetg]

ok..nevermind...i just noticed the width of the axle is 10mm but, the height(?) can vary. I need to measure it, but I am sure the smaller 8Fun motor is 12mm and the bigger 500 watt motor is probably 14mm. I recall i had to file out the dropout to make the slot deeper, and not wider. I am afraid the filing has weakened the dropout.

 

[sonnetg]

First: You need to get used to the idea of having a torque arm for a 1000W bike. Dropouts, no matter how beefy, all have open-ended slots by design. That allows your flatted axle to pry the slot open. Even if the material is super strong and can recover its shape, the axle will be damaged by twisting into a sprung-open slot.

A torque arm can be much flimsier-looking than the dropout, but still be much more effective if it has a closed slot.

Have a look at single speed MTBs. They are made of chromoly more often than not, and their rear opening dropouts tend to be beefier than the run of the mill.

Just an FYI...I have decided to go with a Surly 1x1. Currently looking out for a deal. Thank you, Chalo.

Will be looking forward to seeing how CroMo holds up against abuse. Still haven't decided which motor, but will start off with a Geared 700 watt (overvolted) MAC-ish type motor and see how it goes. Then porbably upgrade to leaf 1500 watt or Mxus :lol:

http://surlybikes.com/bikes/1x12

If Surly doesn't workout, it will have to be Flux or Raptor or another bicycle shaped object... :wink:

Cheers.

 

[Chalo]

Have a look at single speed MTBs. They are made of chromoly more often than not, and their rear opening dropouts tend to be beefier than the run of the mill.

Just an FYI...I have decided to go with a Surly 1x1. Currently looking out for a deal. Thank you, Chalo.

Will be looking forward to seeing how CroMo holds up against abuse.

Surlys are great no-nonsense bikes, but they use cast dropouts. Like for like, they'll be softer than forged dropouts or those made from wrought plate. I think the dropout on the Troll would be a more rugged choice, with a lot more features to which you could easily bolt a torque arm.

Versus

I think the hooded section of the 1x1's dropout will cramp your style big time.

 

[sonnetg]

Surlys are great no-nonsense bikes, but they use cast dropouts. Like for like, they'll be softer than forged dropouts or those made from wrought plate. I think the dropout on the Troll would be a more rugged choice, with a lot more features to which you could easily bolt a torque arm.

Versus

Holy smokes dude. You seem to be like the encyclopedia of bicycles. I had later changed my mind and decided to go with the Troll just because it had a rear rack braze-on, and also the option for derailleur mount. I am also eyeing on the Flux Beta, but something like that would attract too much attention and questions on the trails. I would like to go as quiet and stealthy as possible.

It seems there is a fair amount of demand for bicycle frames ready for eBike conversion, but not much options out there except for motocross/hybrid bike frames. bummer..

 

[2old]

You might look at Nashbar; my $80 ($100, but frequent 20% off "sales") steel frame with mostly mild steel tubes is heavy, but pretty beefy. Currentlu using it for a mid drive platform, but looks like it would be good for hub motors too.

 

[wesnewell]

I've never used torque arms and have never had a problem with my 1000W rear hub motor since installing jam nuts on the inside of the *steel* dropouts. I run the motor at up to 4000W using regen braking on 24s lipo at 100.8V fully charged. I do have the torque washers that came with the kit on both sides. As long as you keep the axle nuts good and tight, use the torque washers in steel dropouts, there shouldn't be a problem. I've got about 13K miles on my current bike and have never had to tighten the axle nuts except when i pulled the wheel to replace the tire. This is just my personal experiences. ymmv. Btw, I wouldn't go without torque plates (not arms) in aluminum dropouts.

 

[ecycler]

I've never used torque arms and have never had a problem with my 1000W rear hub motor since installing jam nuts on the inside of the *steel* dropouts. I run the motor at up to 4000W using regen braking on 24s lipo at 100.8V fully charged. I do have the torque washers that came with the kit on both sides. As long as you keep the axle nuts good and tight, use the torque washers in steel dropouts, there shouldn't be a problem. I've got about 13K miles on my current bike and have never had to tighten the axle nuts except when i pulled the wheel to replace the tire. This is just my personal experiences. ymmv. Btw, I wouldn't go without torque plates (not arms) in aluminum dropouts.

Those stats are impressive. What frame? You might as well go buy a some powerball tickets with that level of luck and all the money you saved from not installing torque arms/plates.

 

[Chalo]

wesnewell rides a Wally World junk bike. He uses Hobby King junk batteries. And he's quick to advise setups that most of us warn against. That said, what he does seems to work for him, so far.

 

[sonnetg]

I've never used torque arms and have never had a problem with my 1000W rear hub motor since installing jam nuts on the inside of the *steel* dropouts. I run the motor at up to 4000W using regen braking on 24s lipo at 100.8V fully charged. I do have the torque washers that came with the kit on both sides. As long as you keep the axle nuts good and tight, use the torque washers in steel dropouts, there shouldn't be a problem. I've got about 13K miles on my current bike and have never had to tighten the axle nuts except when i pulled the wheel to replace the tire. This is just my personal experiences. ymmv. Btw, I wouldn't go without torque plates (not arms) in aluminum dropouts.

I agree. If you tighten the bolts with an inch of your life, the axle shoudn't spin. And I can bet these wally world steel frame bikes will out perform most fragile and expensive Aluminum MTBs. I currently use a front fork mounted 350 Watt motor, and never had any issues, but never say never...

That's being said, mind posting a picture of your dropouts?