Modded Dropouts Or Naw?

[500w_Of_Power]

Hi, I'm building a 1500w e-bike on 48v and the dropouts are aluminum, they just barely go over the axle. I was thinking of machining some 1/4in 304 stainless steel from SendCutSend to make extended dropouts, then adding a torque arm. I would bolt them on, and use JB Weld Steel epoxy for added strength. You can see my cardboard and paper mock-ups. Is this a good idea, or should I look for a steel frame? This frame is a DimondBack Overdrive 27.5 large frame: https://www.costco.com/diamondback-overdrive-27.5"-bike.product.100744715.html

 

[amberwolf]

Nothing wrong with making torque plates for it, but keep in mind that if you move the center of the axle somewhere other than where the existing dropouts put a bicycle wheel axle (not the larger motor wheel axle), the disc caliper mount won't put the caliper in the correct place to line up with the rotor.

There are a bunch of examples of torque arms and plates you can examine in various threads and posts around here, including clamping / pinching ones that will do the best job of securing the axle in place. One of the biggest collections is the Torque Arm Picture Thread. torque arm picture thread

 

[E-HP]

Hi, I'm building a 1500w e-bike on 48v and the dropouts are aluminum, they just barely go over the axle.

If you're gong to use two torque arms, then I'd just take a jeweler's file and a round file to deepen the existing dropouts by 2mm. Use the round file to remove any corners. Just make sure you get tight fitting torque arms and you'll be fine.

 

[calab]

Bolt and epoxy them on = naw

Weld on = maybe, depends on how much extra material and welds you putting on. Some people weld up an entire rear triangle for full susp. like the guy was selling for that Walmart bicycle.
Yes to weld on some 1/4" rectangle plate to the chain stay and the seat stay, and route in your slots. Nice beads, nickels as they say. Aluminum a different beast, sorry about that, that takes a lot of skill to weld alum. Some alum needs heat treatment like that 60xx stuff I think. Steel frames should be your next frame.

yaw = get a new/used/ANY frame and do your fancy, beefy, stout t.a.'s
dont dick around with safety, unless you go overboard with the option of "Weld on"

you could incorporate the disc mount into your new ta if you still want to hack around with what you got.

 

[500w_Of_Power]

Nothing wrong with making torque plates for it, but keep in mind that if you move the center of the axle somewhere other than where the existing dropouts put a bicycle wheel axle (not the larger motor wheel axle), the disc caliper mount won't put the caliper in the correct place to line up with the rotor.

There are a bunch of examples of torque arms and plates you can examine in various threads and posts around here, including clamping / pinching ones that will do the best job of securing the axle in place. One of the biggest collections is the Torque Arm Picture Thread. torque arm picture thread

I would not be moving the center of the axle, just making an extension of the dropouts. Do you think they will hold with 1500w?

 

[E-HP]

I would not be moving the center of the axle, just making an extension of the dropouts. Do you think they will hold with 1500w?

With good torque arms you can run double that without the dropout mod, so just invest the dropout money in better batteries where it will add some benefit.

 

[500w_Of_Power]

With good torque arms you can run double that without the dropout mod, so just invest the dropout money in better batteries where it will add some benefit.

Cool!I got 2 torque arms just in case! Thanks!

 

[500w_Of_Power]

Cool!I got 2 torque arms just in case! Thanks!

I still want to run the dropout mod just to be extra safe. Thank you so much for the information.

 

[E-HP]

I still want to run the dropout mod just to be extra safe. Thank you so much for the information.

Good idea if you plan to upgrade to 5kW or more in the future.

 

[500w_Of_Power]

Good idea if you plan to upgrade to 5kW or more in the future.

Maybe I will upgrade to 3kw but 1.5 is enough for me.

 

[E-HP]

Maybe I will upgrade to 3kw but 1.5 is enough for me.

Of course we're only talking battery and controller. Your motor can already handle 5kW, just not continuously, but adding Statorade would be a good idea even at 1.5.

 

[500w_Of_Power]

Of course we're only talking battery and controller. Your motor can already handle 5kW, just not continuously, but adding Statorade would be a good idea even at 1.5.

Thanks. I'm just really cautious about dropouts so I only want to run 1.5kW. So the dropout mods will definitely hold?

 

[E-HP]

Thanks. I'm just really cautious about dropouts so I only want to run 1.5kW. So the dropout mods will definitely hold?

Sure, as long as you have enough axle. About 3/4” for the dropout, dropout mod, and torque arm. Plus the inner washer and axle nut. So around 1 1/2” should do it and have full engagement of the axle nut.

 

[500w_Of_Power]

Sure, as long as you have enough axle. About 3/4” for the dropout, dropout mod, and torque arm. Plus the inner washer and axle nut. So around 1 1/2” should do it and have full engagement of the axle nut.

Yeah, I have enough axle. Thank you so much for all the info, I will send a picture your way when I complete the build.

 

[99t4]

So the dropout mods will definitely hold?

They will definitely hold better if you make them pinching/clamping dropouts, as mentioned above by AW. Your (caardboard mockups) design is begging for them.

 

[E-HP]

They will definitely hold better if you make them pinching/clamping dropouts, as mentioned above by AW. Your (caardboard mockups) design is begging for them.

If clamping is an option, then go with 3/8" thick dropouts and skip the torque arms. That will make taking the wheel off a lot less hassle.

 

[500w_Of_Power]

If clamping is an option, then go with 3/8" thick dropouts and skip the torque arms. That will make taking the wheel off a lot less hassle.

How would I make them clamping/pinching? This is my first-ever attempt at doing something like this. I would like to stick to my original design, but clamping the sounds interesting.

 

[E-HP]

How would I make them clamping/pinching? This is my first-ever attempt at doing something like this. I would like to stick to my original design, but clamping the sounds interesting.

There are examples on this thread, but if you go with 3/8", that's wide enough to drill and tap the clamping bolt.

Giant DH Comp Drop Out adapters and conversion

Giant DH Comp/team drop out adapters. Will suit both 135 and 150mm drop outs. Will take up to a 16mm axel, eg, Mac, NC, Xlyte, Cromotor Cost: USD$185 shipped to Aus and USA USD$195 shipped to Europe Fork Lifts for mounting batteries on tripple clamp forks Production of the KIWI drop outs...

endless-sphere.com

 

[500w_Of_Power]

So it would go on the back side, eliminating the need to tap/drill a hole through the existing dropouts.

 

[amberwolf]

How would I make them clamping/pinching? This is my first-ever attempt at doing something like this. I would like to stick to my original design, but clamping the sounds interesting.

See the thread I previously linked for many examples of various types of torque arms and plates. you can also look around the forum for clamping or pinching dropouts and find even more examples, including those on my SB Cruiser trike.

 

[500w_Of_Power]

Thanks for the info. I think I will go with my original design and have a plate on the back about 1/8in thick for added support.

 

[99t4]

How would I make them clamping/pinching?

Here is a crude example that clearly shows the pinching feature:

Looks like you can easily incorporate the drilled holes and bolts into your design.

 

[500w_Of_Power]

I'm just really nervous about doing this, I'm only 15 and I don't want to die when my custom dropout fails at 35mph.

 

[99t4]

Smart not to take extra risks at 35mph. Things can turn ugly real quick.

Can you enlist someone local to you who is more experienced in basic metalworking, to help you fabricate your dropouts?

 

[lnanek]

Maybe you should choose your torque arms first. The ones I use have metal plates that wrap completely around the axle, so it's impossible for the hub to drop out unless the fork split open sideways: