View Full Version : Rear wheel drive

09-17-2012, 11:11 AM
This may be obvious to the experienced delta trike builders but it's not evident from the Aurora pictures. So

a) is only one rear wheel driven? and if so
b) is that adequate?


09-17-2012, 11:40 AM
I will attempt to answer this. When going around corners the outer wheel will turn at a different speed then the inner wheel regardless of which wheel is driven. This causes wear and drag if both wheels are driven without a differential of some sort to allow the outer and inner wheel to spin at different rates. There are differentials out there and there are methods of create a differential. But they take some doing and Brad's plans are built with the idea that anyone with the bare essential tooling can build the bike or trike.
The plans are basic guidelines to build a bike/trike just follow step by step. If you want to modify the plans to suit your needs then go for it. The delta trikes with single wheel drive ride great from what I have read. And only if you plan to deal with lots of snow, sand or deep of road mud puddles would you need a dual rear drive. Hope that helps. Welcome to the group and be sure to post pictures of your project when you get started we love pictures. Even failures as it helps everyone to know what does or doesn't work.

09-17-2012, 12:36 PM
Hi Adrian,
This is probably the hardest feature of a trike to understand.
I did not believe until I builkt mine and got it on the road.
My experience has been motor trade, cars, bikes , busses, trucks, racers etc, where a diff is used every time.
To me, one wheel drive was crazy. But I am living in China, and every peddle trike here is one wheel drive, so they can't all be wrong.
Engineering and auto experience say this is wrong.
'My experience is that under normal driving, I don;t know which wheel is driving or braking!!.
If I push real hard into a left hander, I do get wheel spin, but thats about the only problem.
Unless you plan on snow mud or sand, one wheel is more than enough, and you do not feel it in the steering.
I ride my trike hands off a lot (!) it tracks dead straight.
If you want more, a ratchet style diff is the only one that will work for you, and it is not hard to make--if you can make the bike, you can make the diff. But you will have to deviate from Brads plans a little.
You can get all the help you need with this deviation.
Steve G,

09-17-2012, 02:38 PM
Hi Adrian
I have a DeltaWolf with only one driven wheel and I'm never aware of which wheel it is. On rare occasions I have a little wheel spin. That would be on gravel or sand pulling uphill. On asphalt or concrete roads there is never a problem and seldom is it a problem on dirt or gravel roads.
So I guess I'll qualify the answer by saying it is adequate unless you are doing a lot of really steep hills or off road. Deep sand also gives me a problem but unless you go to really wide tires I doubt if a differential will make much difference.

PS Adrian, I live in a hilly area and have not been on a hill steep enough to be a problem as long as it is any type of hard surface pavement.

Radical Brad
09-17-2012, 07:16 PM
Yes, it is completely unnoticeable and will ride just like a two wheeler for traction.


09-18-2012, 11:25 AM
Thanks for all the excellent feedback. My build experience is limited to this Voyageur (http://www.brennans.net/adrian/bike/), so please excuse the newbie trike questions.

Moving on from going to stopping, according to the description the Aurora has dual rear disc brakes. How does braking on one side effect steering? Does the trike stop in a straight line when one rear brake is applied?


09-18-2012, 11:42 AM
I only have one disk brake on the back of my DeltaWolf and it is on the driven wheel. I notice no pull to the side when the brake is applied.

09-18-2012, 12:44 PM
I only have one disk brake on the back of my DeltaWolf and it is on the driven wheel. I notice no pull to the side when the brake is applied.

Thanks Tuff. Time to buy the plans and start on a new trike I think...

09-18-2012, 10:38 PM
when it comes to one wheel braking, there is a very slight pull to the braked side. I proved this in the only way possible.
An elastic band on the brake and hands off the bars!
It is so slight that you cannot really feel it when your hand is gripping the brake lever-thus holding the bars!
If you had a seperate, frame mounted brake where you could apply the brake with hands totally free of the bars, it will pull slightly. I suppose the shorter the wheel base the more the pull, but it is slight.
Even when you do lock up a real wheel, the trike still tracks dead straight! Because the un-braked wheel keeps it on a straight line.
This is one case where practice completely over-rides any engineering theory!
The advantage of braking on two rear wheels is that you still have brakes when the load one wheel is reduced.
Put it this way--Assume you are moving along the side of a hill, moving slightly down hill--just rolling along.
The hill gets steeper, so you go a bit faster Your brake is on the high side of the hill.
There is very little weight on the high side wheel, and heaps on the low side (you are nearly rolling over!!
So you hit the brakes. The wheel locks instantly because there is no weight on it , and you keep rolling accross the hill at an ever increasing speed.
In this situation you only have two ways to get brakes -turn down the hill to get weight onto the braked wheel -safer way,
or turn up the hill --the instinctive response--when you roll over instantly!.
Now apply the same ideas to a corner, and you will see that (with, say, right side braking) you have reduced braking in a right hand turn. It does not take much of a turn to cancel out the brake.
So if you intend off road use, or in a hilly area, I suggest you need dual rear brakes. In dead flat Beijing it is not an issue.
While we talk of brakes and hills, it is a good time to throw in a hint that you build in a parking brake now, and not after the final paint job, and the trike/ quad has just rolled over your foot!
A well built trike or Quad is almost usable as a builders level!
Steve G