Trailer hitch for e-bikes

[WheezyRider]

I've recently invested in a trailer to increase load carrying ability, but have run into a snag. The hitch is designed for a 10 mm back axle, whereas with a hub motor, the axle is 12 mm. I've drilled out the hole in the hitch to fit the axle, but then the axle nut is too big to fit in the recess on the hitch. I've machined a spacer to effectively fill in the recess. Can anyone see a flaw in my cunning plan? How do others on here overcome this problem?

 

[guerney]

That looks exactly like my Homcom trailer's hitch - my experience has been that no matter how tightly it's bolted through, the hitch always turns, which could mean that it also moves from side to side... therefore a strong stainless steel washer large enough to cover both, might be wise to add? Or machine a stepped piece instead? Aluminium washers bend, warp, stretch and are destroyed, as I discovered - I had tried using an aluminium washer between the hitch and the droput, because the hitch kept turning and I worried that it would wear the droput - the mangled washer ended up inside the dropout, seizing that wheel. I needn't have worried, because that part of the dropout has a steel piece embedded into the aluminium dropout. And that's something else Dahon got right.

 

[matthewslack]

Try it and see first.

Worst case is improvise a mounting direct to the frame tubes as I did to overcome rack issues.





Two layers of 1mm aluminium sheet and various layers of polythene cut from a cheap Lidl chopping board and stainless steel bolts.

 

[jimriley]

I have similar trouble, considering welding an arm going forwards to butt up against the underside of the frame tube to stop rotation. Awaiting delivery of a round tuit, used my last one up.

 

[flecc]

How do others on here overcome this problem?

All cycle trailer hitch arrangements are horrible so I decided from the outset to have central rear hitching, car style. My large trailer is based on an expanded version of the Homecom chassis, like Guerney's, but its whole towbar and hitch was scrapped on receipt.

My hitches are miniaturised ball joint and cup on the end of central towbars and this enables two trailers when extra capacity is needed, as seen on this link.

All parts fabricated as necessary and the towball mountings on both bikes are connected to the mudguard and carrier mounting points, either directly or via the carrier tubing where strong enough.
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[WheezyRider]

All cycle trailer hitch arrangements are horrible so I decided from the outset to have central rear hitching, car style. My large trailer is based on an expanded version of the Homecom chassis, like Guerney's, but its whole towbar and hitch was scrapped on receipt.

My hitches are miniaturised ball joint and cup on the end of central towbars and this enables two trailers when extra capacity is needed, as seen on this link.

All parts fabricated as necessary and the towball mountings on both bikes are connected to the mudguard and carrier mounting points, either directly or via the carrier tubing where strong enough.
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It says the max load of the trailer should not be more than 26 kg, so I suppose that's why they don't worry about hitch rotation.

I've thought for a while that a centre coupling arrangement would be much better, but wondered how best to attach something to the frame without damaging it and then would it also need a diagonal stay to create a proper triangular support...

Where did you get a bike proportioned tow ball? Car tow balls are quite heavy.

I'll see how I get on with the modified hitch for the moment, it's just a cheap steel frame trailer with steel wheels, but in the future I'd like to build something lighter and more suitable.

 

[guerney]

@WheezyRider - I'm interested as to which trailer you have.

 

[flecc]

Where did you get a bike proportioned tow ball? Car tow balls are quite heavy.

The original steel ball and the matching cup came on a cheap French small trailer I spotted in a cycle discounter (CycleKing).

But when I needed a second ball for the other bike, scouting around I found a a bottle top on a discarded scent bottle that was a neat sphere of solid plastic, so I adapted that. Greased it has always worked perfectly.

However, before that first towball turned up, for a short while I used truck style centre hitch, a pair of plates on the bike with a single one on the trailer and a drop in bolt to link them. This style of thing but lightweight and with enough spacing to allow the bike to bank when towing:

 

[Raboa]

I got a couple hitch brackets made to fit on an ebike axle, you attach the standard to the below using a nut and bolt.

I also made one where the axle hole is straight but I can't find the photo

 

[Nealh]

I haven't a pic yet but on my Ute, I have heath'd a solution that works by securing a main angled support to the rear frame and the CF hitch simply bolts to the bottom of the angled support rearwards of the axle. The Ute being along tail is designed with extra framework to the rear.
I will try and take some pics soon.

With the roadrat with the alfine 8 a CF hitch simply pinches up tight on the drop out , it doesn't twist with a 100kg load infact last year I had some 125kg plus on the trailer and the hitch didn't budge.

 

[WheezyRider]

Interesting to see how people have addressed the problem. It's surprising there isn't a commercial product for this considering how many e-bikes are around now and how transformative in terms of load carrying it is combining e-bikes with trailers. A lot of car journeys can be replaced by using a trailer.

 

[WheezyRider]

@WheezyRider - I'm interested as to which trailer you have.

It's just one of those generic cheap Chinese steel frame, steel wheel jobs I bought online. I can upload pics if you are interested.

I have been intending to build the ultimate trailer for years, but never end up having time and have not progressed beyond buying the wheels and tyres

So I thought I'd just get a cheap trailer to get me started, gain experience and reduce the number of car trips I need to take.

 

[WheezyRider]

I got a couple hitch brackets made to fit on an ebike axle, you attach the standard to the below using a nut and bolt.

I also made one where the axle hole is straight but I can't find the photo

That's nice, I like it. You could even make it a bit bigger and put ridges around where the hitch attaches, so it can't rotate in the vertical plane. The flats on the main axle hole should stop rotation there too.

 

[Raboa]

The brackets were laser cut by a local company, I have a couple spare. private message me if interested.

 

[WheezyRider]

The brackets were laser cut by a local company, I have a couple spare. private message me if interested.

Thanks, that's a really kind offer. However, I've got access to a CNC machine at work, so I'll take your inspiration and adapt it

Maybe others on here might appreciate one. Perhaps you could even put your spares on eBay and see what interest you get?

 

[WheezyRider]

The original steel ball and the matching cup came on a cheap French small trailer I spotted in a cycle discounter (CycleKing).

But when I needed a second ball for the other bike, scouting around I found a a bottle top on a discarded scent bottle that was a neat sphere of solid plastic, so I adapted that. Greased it has always worked perfectly.

However, before that first towball turned up, for a short while I used truck style centre hitch, a pair of plates on the bike with a single one on the trailer and a drop in bolt to link them. This style of thing but lightweight and with enough spacing to allow the bike to bank when towing:

View attachment 50179

I've wondered whether something like this would be ok, if it would give enough movement.



Alternatively, perhaps a tie rod end off of a car?

 

[flecc]

I've wondered whether something like this would be ok, if it would give enough movement.

View attachment 50183

Alternatively, perhaps a tie rod end off of a car?

View attachment 50184

The car tie rod end would probbly be rather heavy, but the top one looks like it could be ideal. I doubt you'll be mimicking Moto GP lean angles when towing a trailer!
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[Raboa]

I have sold some of the brackets on eBay, there is hardly any profit in it. One change I would make is to make the axle end hole a tighter fit, it is slightly loose due to my miscalculations. Some people have said that they prefer this as it gives them a bit of leeway when fitting the bracket. Thanks for the compliment.

 

[Nealh]

The CF gets over the twisting action by using a super flexible elastomer to connect to the hitch. Early on in my use I managed twice towing the crate, to over turn the trailer and the elastomer takes the twisting in it's stride.

Apart from the price , the axle hitch and elastomer one could use them for most trailers, the elastomer simply slides in to the 25mm draw bar end and is then bolted thru. The axle hitch has a bush for a qr axle or with it removed is 9mm for hubs gears, for a 12mm hu motor one would have to drill it out.

 

[WheezyRider]

The car tie rod end would probbly be rather heavy, but the top one looks like it could be ideal. I doubt you'll be mimicking Moto GP lean angles when towing a trailer!
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Yes, the tie rod end might be a bit on the heavy side. Another option might be a suspension drop link. They are a lot lighter. Cut one in half and you get two for the price of one