130mm dropout hub motor? Or cassette reduction? (was 120mm rear dropout ebike kit)

[DeluxeMC]

I have a road bike that I am trying to convert to an electric one. I need something along the lines of a geared 120mm rear dropout hub motor that is 48v and 1000w. The one I have currently is a 135mm dropout. It also needs to be a 700c wheel size. The problem is that the sprocket is just a freewheel and not a screw on one and the rim is shifted over too much because of this and touching the frame. I cannot get it to fot in and the only solution i have thought of is to either grind down the freewheel or just sell it on ebay or return it. Help please I have ordered the wrong kit 3 times because this road bike has so many stupid things about it.

 

[amberwolf]

The problem is that the sprocket is just a freewheel and not a screw on one

do you mean it is a freehub? because a freewheel does screw on; a freehub is built into the hub itself and always sticks out quite a lot.

if it is a thread-on freewheel, and not a freehub, if you can live with only one pedal gear on the back, then depending on how wide the existing freewheel is, you could save the 15mm you need by changing to a single sprocket (bmx) freewheel.


if it's a freehub, then you can't do it that way, and grinding it down will destroy it, making you unable to pedal the bike at all.


if your bike is only 120mm dropouts, then you will want to look for a motor kit that has those specifications, and if it does not, do not buy it.

if it is not in the right size wheel, you can always have it relaced in the size rim you need, by any reputable bike shop, or you can even do it yourself if you're willing to learn (it's easy, it just takes time and patience, once you buy the right size rim and length of spokes).

there are a number of discussions and pages about 120mm dropout motors here on es and around the web, if you can't directly find a site selling one; one possible search for them:
https://www.google.com/search?q=120mm+dropout+ebike+motor


however....if your roadbike has a standard bb (where the pedals are), another option is a middrive, like the bbs01, 02, or hd, etc., tsdz2, or various others. then you don't have to replace your rear wheel at all, just keep the regular one.

 

[zeccato]

if you have a 135mm dropout
with a 6-7speed freewheel
you should be okay, I think.
Maybe it'll help: but a 8T or 10T 12T
https://endless-sphere.com/forums/viewtopic.php?f=3&t=103288

 

[DeluxeMC]

Thank you guys for helping!

 

[DeluxeMC]

The problem is that the sprocket is just a freewheel and not a screw on one

however....if your roadbike has a standard bb (where the pedals are), another option is a middrive, like the bbs01, 02, or hd, etc., tsdz2, or various others. then you don't have to replace your rear wheel at all, just keep the regular one.

Could i just get a hub with a screw on mount for a cassette and then get a 6 or 4 speed cassette to make sure it fits?

 

[amberwolf]

a cassette requires a freehub, which is built into the wheel. a cassette doesn't have threads, it has splines.

if you have a thread-on hub, you use a freewheel (whcih can have just one, or multiple, sprockets on it).

take a look at sheldon brown's bicycle repair/maintenance site; you'll learn a lot from that (it's where i started reading a long time ago--even if some of the info is dated, it still applies).

 

[DeluxeMC]

Hi, I was wondering if anybody could give me their insight on how to go about this problem. Right now, I have a customer that paid me to have their bike converted to electric. It is a Specialized A1 Bike with 130mm dropouts on the back. Most bike kits are 135mm, and I learned this the hard way because I bought a 700c 48v 1000w Geared Rear Hub Motor Kit from Calibike and realized a little too late that the hub wouldn't fit the bike. I have tried flexing the frame, but I am really worried that I might permanently damage my customer's frame if I do that. The only real solution to this problem I have thought of is send this kit back and get another kit that has a screw on freewheel mount instead of a freehub mount and get something like a 6 or 5 speed cassette so I could take out some space. If you guys know of any 48v 1000w kits out there that have 130mm dropouts, PLEASE link them to me. Thanks!

 

[docw009]

You bought something like this with the cassette? Cassettes, you know, are preferred because they are stronger than freewheels.
https://calibike.com/product/48v-1000w-33-mph-3kg-water-proof-easy-connect-ebike-kit-complete/

I just had a similar install issue. My motor, for some reason came out to be 138mm.I had bought two others prior (from different vendor) and they were 135mm exactly. I didn't want to be spreading the frame 3mm. It was aluminum, and had a built-in luggage rack that made it very stiff.

I trimmed a spacer to get it down to 135mm, but now the 7 speed freewheel hit the frame. So I switched in a 6 speed. That only saved 3 mm. but it was enough.

You should find out the widths of the 5 speed freewheels, and whether you can lock out a 7 speed shifter to work with it, or if you need to change that too.