130mm Rear Hub Motor?

Hello all,

Got an old Fuji Bikes Absolute 3.0 frame from a friend. Sadly it turns out to be Aluminum and only has 130mm rear dropouts. I can't find any 130mm rear hub motors at all. Even if I somehow pull the dropouts to 135mm I'm having trouble finding anything over 1000w. It appears it may be very dangerous to pull an aluminum frame?

Is my only option to try and find a higher power mid drive unit? This bike appears to have 700c wheels (is that 28 inches?), and I would like to go a stable/easy 32-34 mph max to make my travel time similar.

Anybody have any recommendations or places I should look?

Thank you, have a good day.

You can safely flex out the frame another 5 mm to cram in a 135 mm motor. 3 mm per side will not crack the frame, it just flexes it, rather than putting a bend in the alloy frame. So just pick a motor, and give it some grunt to stuff it in when you mount it. Don't get the car jack out, and try to put a permanent bend on an alloy frame.

Its also possible to put a different freewheel on it, then shave the axle shoulder to fit smaller frames. This would also mean dishing the wheel, so its a pita to take that approach..

just flex that frame out enough to put the motor in, then do adjustments to the derailleur stops.

You can give a 1000w kit dd motor, which in fact is a 500w rated motor, 2000w without problems. so run it at 48v 40 amps. or 72v 30 amps.

Thank you very much dogman Dan. I appreciate the response.

I did a few tests, and without tools, I was able to pull the rear dropouts to 135mm pretty easily.

Looking for a motor first I guess, then a controller. Even with 135mm as my new size, there doesn't appear to be a ton of options?

I found the DD45 Standard: (out of stock)
https://www.ebikes.ca/shop/electric-bicycle-parts/motors/dd45-std.html

9C212 Standard: Seems about the same as the DD45, just lower top speed maybe?
https://www.ebikes.ca/shop/electric-bicycle-parts/motors/9c212-std.html

A generic QS motor for 135mm:
http://www.qs-motor.com/product/1500w-electric-bike-spoke-hub-motor/

Is there any others I should be adding to my list?

TweakGames said:

Looking for a motor first I guess, then a controller. Even with 135mm as my new size, there doesn't appear to be a ton of options?

Click to expand...

It's probably the most popular size, so there are a lot of options. However, choosing an option depends on how your friend intends to ride the bike, the terrain, and range requirements.

Thank you E-HP.

That may be where I am making a mistake. I am having trouble finding them listed as 135mm, maybe because it is the standard,so they don't list it.

We have about 250 used 18560 cells and hope to get 38 mile range from it. (Home to office and back.) Unable to charge at the office. We have some serious hills on the way the would like to be able go up. I think it would be safer to over build / power it than not have enough. It has 700c wheels on it now, and looking to have a top speed of 32-34 mph if needed.

From what I can find with the DD45 for example, their simulator says, 34 MPH top speed, with 72V, 23 Ah battery, and 25A controller. Says the range is only 31 miles however with the 23 Ah. With our 250 cells, in 20S15P (used cells) I bet we are only looking at 20 Ah max. Looks like we need some more cells too.

Does this simulator look correct for our goals? Do you recommend this motor for these goals / wheels / frame?



Thank you.

TweakGames said:

It has 700c wheels on it now, and looking to have a top speed of 32-34 mph if needed.

From what I can find with the DD45 for example, their simulator says, 34 MPH top speed, with 72V, 23 Ah battery, and 25A controller. Says the range is only 31 miles however with the 23 Ah. With our 250 cells, in 20S15P (used cells) I bet we are only looking at 20 Ah max. Looks like we need some more cells too.

Click to expand...

Your range is limited by your desired speed. If you drop your speed to 30 mph, your range goes up to 43 miles.
https://www.ebikes.ca/tools/simulator.html?motor=XF_DD45_4T&batt=B7223_AC&cont=C25&wheel=700c&hp=0&axis=mph&autothrot=true&throt=67.2

If you drop to 25 mph, you range goes up to 60 miles.
https://www.ebikes.ca/tools/simulator.html?motor=XF_DD45_4T&batt=B7223_AC&cont=C25&wheel=700c&hp=0&axis=mph&autothrot=true&throt=54

The more challenging issue may be the hills, but it looks like you could go 30 minutes with a 10% grade before meltdown, so that's pretty good.
https://www.ebikes.ca/tools/simulator.html?motor=XF_DD45_4T&batt=B7223_AC&cont=C25&wheel=700c&hp=0&axis=mph&autothrot=true&throt=100&grade=10

Awesome information E-HP, thank you for taking the time to share that.

Looks like I can avoid the hill issue by getting "statorade". The simulator says it can do 15.5% grade for 55 minutes at 15.1 mph with the statorade. Wow!

Ok, looks like the DD45 will be the motor I get, with statorade and maybe some heatsinks. I hope it comes back in stock soon!

The range difference between 34, 30, and 25 mph is crazy! I guess we will just have to test it and see how it does.

Next is the controller I assume? Any recommendations for a 72V 30 or 40 amp controller I should be looking for? We like to tweak and experiment, is there a specific kind of controller that allows you to change a lot of settings and variables? Regen and all the fun features?

I was looking at the "Grinfineon 40A" but it appears to be a few years old already? Maybe something newer / better has been released?

Thank you.

You will find in the real world, you can't just commute forty miles a day at close to 35mph plus on that tire. Oh sure, racers do huge miles at 30 mph all the time. And get flats all the time, and have a chase car with wheels.

25 mph cruise allows you to see that stuff on the road, and you can avoid some of the flats, 35 doesn't. Plan on about 20-25 mph, which btw your bike gears can match, and then your battery won't have to be so big. I started out commuting as fast as it could go, but after a few years, I found that slowing down meant I did not have to true a wheel weekly, fix a flat out on the road monthly, adjust break pads monthly, etc.

Aiming lower also means you can get by fine on a 1000w type system, provided the rider is under 250 pounds. But a more powerful motor will mean faster on the uphills, and can be well worth it.