# Trike layout question



## Woodsmith (Jun 5, 2008)

The usual layout of reverse trikes seems to come in two flavours.
Front drive with motor and transaxle at the front as if it were a front wheel drive car.
Rear drive with mid mounted motor and transmission as if it were the back of a motorbike.

So, is there any reason why a reverse trike couldn't/shouldn't have a front motor driving the rear wheel through a propshaft?

I was just sketching ideas around a short wheel base, single seat trike. With the seat just ahead of the rear wheel and batteries under the floor it might make sense to fit the motor ahead of the foot well around the front axle line. It would make even more sense if it were direct drive onto a shaft drive swing arm at the rear. The propshaft could run through a space between rows of batteries. I appreciate that there may be more significant transmission losses but the extra weight may be accommodated by having less chassis length.

Just thinking of the old Morgan trikes with a V twin hanging off the front.


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## madderscience (Jun 28, 2008)

what would be the point of putting the motor so far away from the drive wheel, requiring heavy propshafts and ruining a good place to put batteries (smack dab in the center, down low) unless the trike is very short wheelbase or something?

Seems like a chain drive and the motor a few inches ahead of the rear wheel (just enough to allow room for fenders, etc) would be simpler. 

If you are trying to balance out the weight, put some batteries up front instead.

Dunno.


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## Amberwolf (May 29, 2009)

Woodsmith said:


> So, is there any reason why a reverse trike couldn't/shouldn't have a front motor driving the rear wheel through a propshaft?


No reason it *couldn't*, but a few reasons you might not want to, such as those Madderscience listed above.

I've been working out various ideas for bicycle-based e-trikes, and most of them seem best with the motor under or just behind the seat, chain or belt drive to the rear wheel, batteries distributed wherever the weight balance works out better (usually up near the front between seat and front wheels as low as I can get them). 

It's a compromise between where you want the weight, how you want the performance/steering to work, suspension action, and the complexity of moving the mechanical power around (and associated losses).

On my bicycle-based versions, it is complicated by the requirement of the functional pedal drive, which must mechanically couple to a wheel and then the road just as the motor does. That pedal drive *is* up front, so it seems to make sense to go ahead and put the motor up there, too, and use the entire transmission mechanism to the wheel for both. But it complicates that transmission by forcing it to be able to handle the motor power, which is considerably higher than pedal power, and changes a number of key intermediating pedal drive components. 

It ends up better for my purposes to move the motor back as close as possible to the rear wheel, with it's own transmission to it. 

That's not a worry you have with your trikes, fortunately. 
________
Avandia Lawsuits


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## Woodsmith (Jun 5, 2008)

I was just sketching ideas with a really short wheel base where the seat is effectively the rear fender over the rear wheel as in some recumbent pedal trikes. There wouldn't be space to fit a motor there so I figured on the motor up front. A prop shaft needn't be that heavy, motor bike sized rather then car sized. Batteries could be on either side of the prop leaving a tunnel and completely within the wheelbase. Only the motor would be ahead of the front axle.

A wheel motor would be a better option but just playing with ideas with something that is smaller then a conventional trike but bigger then a pedal powered trike, the sort of size that doesn't warrent a front drive trans axle.


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## Amberwolf (May 29, 2009)

I think you're definitely going to want a lot of the rest of the weight up front and down low if you put the seat over the rear wheel, to help prevent tipping in turns at speed. (depends on your suspension geometry, and if it's a tilting design).

Putting the motor up there would be a good idea in that case, if everything else is very light up there. 

Depending on your motor type, it can go alongside the rear wheel (or even inside it). There are some Fisher and Paykel (sp?) pancake BLDC washing machine motors from down under converted over to e-trike motors. They might potentially be rewound for a few kW output, depending on cooling methods; I'm not sure what they could handle with the original windings. Some people are working on getting me some to play with, over on Endless Sphere. 

Other people on ES are working on some axial-flux pancake designs for several kW output, and others have already created controllers capable of running them. 

One or more types of those motors and/or controllers would probably run your trike, depending on your power requirements.
________
grandma Webcams


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## TomA (Mar 26, 2009)

Woodsmith said:


> So, is there any reason why a reverse trike couldn't/shouldn't have a front motor driving the rear wheel through a propshaft?


Short answer: No.

But, this is something of a tricky trike question...

The longer answer, as is so often the case in vehicle design compromises of every stripe, is that it depends on many things- How much power, where is the cg of the vehicle, what are the tire contact patches, suspension design and dimensional relationships (wheelbase, front track, effective half-tread,) etc. etc. An answer won't have much value in the abstract.

For a light vehicle like you're describing, it probably doesn't matter where the motor is, but it matters a great deal where the weight is- 1/3 on each wheel is ideal for a reverse trike, and as low as possible is essential for stability. 

I'm working on a 400lb reverse trike, 650lb GVW, and the BLDC motor is in the rear wheel hub. I'm currently playing with the wheelbase, track, and moving the pilot and the batteries (165lbs of Lion) around to balance the weight properly. If it were much heavier, say 1000lbs, I'd be looking at front drive with a series DC motor. A little heavier than that, say 1600+lbs, and I'd have modest front drive AC power, with a series DC "boost" motor for the rear wheel for hills and fast starts, with a freewheel clutch. All of these basic strategies are an attempt to balance trade-offs in performance, packaging and cost, and the devil is in the details. 

This why a scratch-built EV is really only maybe 1/3 about electric vehicles, with the majority of the work being standard motor vehicle design, construction and performance issues. Being electric only changes the weight, power and cooling requirements of the vehicle. Basically, it comes down to what you are doing with the vehicle, what parts you are going to use, and the best compromise you can strike. 

For myself, I would make the wheelbase longer and put the motor behind the pilot. Its just simpler. At this size vehicle and power level, a front-to-back propshaft is a big drag and a packaging problem. If you can live with that, fine; go for it.

Again, the short answer: There's no reason why a rear-drive reverse trike can't be effectively engineered with a front motor. The Morgan SS is one classic example (with significant racing pedigree) that proves it.

TomA


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## Woodsmith (Jun 5, 2008)

Thanks for the complicated answers, there are a lot of issues to take into account.

This is just a thought excercise much a bit like wondering if an ICE couldn't go sideways at the front to drive the front wheels.

Getting good weight distribution at this scale is the problem as the driver will be a significant proportion of the vehicle weight. Added to this is single rear wheel drive for simplicity where front wheel drive would be preferable but could be more weighty and complicated.


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## TomA (Mar 26, 2009)

Woodsmith said:


> Getting good weight distribution at this scale is the problem as the driver will be a significant proportion of the vehicle weight.


Funny you should mention it...

My trike will be built for me, but it was a real problem getting the numbers to add up with me being 250lbs. I took the radical step of going back to what I weighed as a teenager almost 30 years ago, and took off 70 pounds. I always wanted to do it, but this project was at a hard stop with a porky pilot and it was the motivational catalyst I needed. I'm 180 after 9 months of increased vigor and eating mostly vegetables.

Now, not only is the trike design back near its overall weight and performance targets, but the vehicle is probably also drivable by my wife, brother-in-law, and other people in the 175-185 range without moving the cg around too much to make the handling unpredictable. How cool is that?

Better yet, I feel fantastic! 

In this weight class of EV, personal "payload" is everything...

TomA


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## dataman19 (Oct 7, 2009)

Take a look at the Aptera design.
..
http://www.aptera.com
...
This is a reverse trike... This car will supposedly run down the freeway at 70Miles an Hour tops. It has also passed DOT Crash Testing...
..
Too bat the Corporate Bozos are fighting with the investors. Over 50,000 sold (with Deposits Paid), yet not a single vehicle delivered to a purchaser to date.
..
By the way, why don't you people indicate where you are located? This would go a long way towards figuring out how to send you for technical help, parts, etc.. Wouldn't it?
..
dataman19


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## Duxuk (Jul 11, 2009)

I am just completing a scratch built trike. The front end has two wheels with anti roll suspension design, which I have found essential in my 600cc Honda scooter powedred reverse trike. At the back I have built a motorcycle type swinging arm on which the Etek RT motor is mounted. Four of the batteries lie down each side of the shallow cockpit area. I then changed my mind and decided I needed 72V, that is 6 batteries instead of 4, just to get the range. I am aiming at 40 miles but only need to drive 27 giving me a safty margin. The other 2 batteries have therefore had to go between my feet/under my knees. It's a bit tight but I fit! I drove 400 yards up our street then it snowed. The ice is still there 3 weeks later, it must be that global warming thing again! I hope to be on the road in about 2 months after 14 months of building. Yes the electrical side is easy, the difficulties have concerned the rest of the vehicle design and construction. I am based in Chorley , lancashire , England. I need to do the MSVA test in order to register the trike. I have had a LA battery pack custom made to give a better one hour rate. The 110Ah batteries will give 62Ah C1. The trike weighs about 100Kg, the batteries 151KG. What range do you think I can expect?


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## Jozzer (Mar 29, 2009)

From your description, I'd say you can expect to use 100wh per mile or a little more. Your estimate of 40 miles max sounds about right.


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## TomA (Mar 26, 2009)

dataman19 said:


> Take a look at the Aptera design.
> ..
> http://www.aptera.com
> ...
> ...


Well, it isn't so simple. Being an OEM is a _lot_ harder than it seems. The last guy to really do it was John Z. Delorean. Before that, Henry J Kaiser. Before that, Walter P. Chrysler. All three of those companies are bankrupt.

"Corporate Bozos fighting with investors" is really more like "there ain't no money to deliver on the marketing." On November 19, 2007 the company announced 2008 delivery of vehicles. That was impossible even during a finance boom. Now there is no money. There will be no cars, at least for 2 or 3 years, and maybe never. That's the way the OEM game is, not being critical, just stating the reality that the business is far, far harder than people know, especially people from Google and Sand Hill Road who have no real chops in the auto industry. Its good that they hired car people to run the company, but what's the first thing they did? 

Delay the product introduction 18-36 months and try to raise more money.

Don't get me wrong, I love the car and want to see it made. I even want to buy one, but as someone who's been following the auto industry closely for 40 years, my head tells me my optimism about the Aptera is a little wishful.

Not to hijack the thread, though, yes, the Aptera is indeed a FWD Lithium/AC electric reverse trike. Nice design, too, maybe the most thoroughly sorted one yet.

TomA


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## TomA (Mar 26, 2009)

Duxuk said:


> I am just completing a scratch built trike...
> 
> The trike weighs about 100Kg, the batteries 151KG...


Hi Duxuk!

Congratulations on getting your build together. I am most intrigued by your weight numbers. Assuming you weigh something over 50kg, your vehicle has a chassis that supports over 200% of its weight.

That's very impressive, especially for something so much larger than a bicycle. Are you using a mild steel or CrMo chassis? I would very much like to see how your trike is constructed. Do you have any pictures of it? 

TomA


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## Salty9 (Jul 13, 2009)

I also am interested in your trike but mostly in your motor-controller combination. I am looking for an ac controller for about 30 kw max.

Chuck


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## Duxuk (Jul 11, 2009)

My trike has a ladder chassis of 25*50*3mm box section with a space frame superstructure of mainly 25*25*1.6mm box. The body work is in 1.2mm aluminium of which I used 4*1.25M squre sheets. The steel when delivered weighed 33Kg. The steel also provided the suspension arms and uprights. The wheels are 2 12" Peugot scooter at the front and a 16" Kawasaki GPX 600R at the back. The motor is an Etek RT weighing 38lbs. The aluminium also provided the seat. The steering column is made from the 25mm box and I have a direct steering link so no heavy steering rack. The vehicle is very minimalist to keep the weight down but has a smooth exterior with a sharp nose to cut drag. The rear body work is also tapered. The top of my head is about 40" from the ground. I am not a computer person so am finding it difficult to post pictures. The power should be 19bhp max which compared to my previous ICE scooter powered trikes should give me about 70 mph but I have geared it for 64mph since I hoped I would get less motor heating and better hill climbing. I would welcome any assesments of my thoughts since I have done this without any consultation, just lots of mainlty web based research.

Andrew Kirk.


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## Woodsmith (Jun 5, 2008)

Hmmm, this has grown a bit without me.

Well, with a bit of luck I should be picking up a late model 2CV gearbox and shafts. It is one with disc brakes.
So, front wheel drive it is then!

I am going to mate it to my golf buggy motor and it can for the back end of my tractor test bed (OK, I've decided the Land Rover axle is a little on the heavy side and is worth more left as it is and sold on again).

However, the same motor gearbox would also form the front end of a reverse trike. With the inboard disc brakes the braking and driving torque will be taken by the drive shafts so the front suspension need only deal with wheel location and springing.

The use of scooter wheels sounds like a good idea, I would just need to find a way to spline the hubs to the drive shafts though that is not insurmountable on a budget.

Duxuk, what is your direct steering like? I am imagining the sort of thing on a child's go cart, a bit of bent rod pushing the track rod back and forth as the steering is turned a few degrees each way.


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## Salty9 (Jul 13, 2009)

Woodsmith,

I picked up a rack and pinion, steering column and subframe from a '80s vintage disposable econo-box that I plan to use for my trike. The steering gear is fairly lightweight and I will lighten the subframe as much as I can. 

Chuck


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## Duxuk (Jul 11, 2009)

Woodsmith,
my direct steering link has been liked on my ICE trikes by the few who have tried it, including Ian Hyne, former editor of Kit Car magazine. It uses a steering column with bearings, not bushes. From this a short drop link has rod ends bolted through. These are attatched to "track rods" which move the steering arms on the suspension uprights. The effect feels like your brain is attatched to the front wheels! It's more a question of weighting the handlebar ends rather than turning the bars, (except on tighter corners). It realy is very precise. It would not work with a heavy vehicle or if you wanted the wheels to turn by a full 45 degrees. I think you also need the leverage of handlebars rather than a smaller steering wheel.


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## Woodsmith (Jun 5, 2008)

Ahhh, so it is like a high tech and properly made version of the child's go cart.

I see what you mean though, direct steering like on a quad bike. That makes sense.

I am trying to figure out what sort of cheap and easily available Euro box would have front wheel drive and wishbones rather then McPherson struts, I can't even find the 2CV front suspension on its own.


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## TomA (Mar 26, 2009)

Its too bad you don't have the 2CV steering setup. That would be the easiest solution, and all the engineering is done.

For myself, I wouldn't use a direct steering linkage, because its just too quick. Less than 1/2 turn lock-to-lock. Even a F1 car is slower than that. This is especially true for front drive, as twitchy handling combined with torque steer will make the trike very unpleasant to drive, particularly in the wet.

I'm using an all-aluminum steering rack from a lightweight dune buggy:

http://www.desertkarts.com/item163927.ctlg

Less than 2 lbs and under $100. There are other options on the same website, including a ratio doubler in the event 12:1 isn't quick enough.

I'm really surprised you can't find a complete 2CV front clip. Even in the US, where they were never common, there are breakers who have these parts. I would take the whole thing, from the front frame stub to the steering box- wheels, brakes and all. The tubular single leading arm front suspension of that car is unique, light, very well-engineered and superbly suited to a front-drive reverse trike. The only thing you would really have to figure out is the springing, and a suitable anti-roll bar device. In my opinion, you'll be money and time ahead paying what you must for the whole 2CV suspension, subframe, steering and brake package and working with it as a unit. You'll also be much more likely to have a properly engineered and functioning trike, since the core design is well-sorted.

Not convinced? OK, there are a bunch of guys making reproduction Morgan 3-wheelers using sliding pillar and wishbone suspensions, with custom fabbed uprights, links and chassis subframes. They are at 3WheelReplicas at Yahoo Groups. Many of those guys are in the UK. The most accomplished of them is named Lito Luciani, and he's in Argentina, making the nicest sliding pillar Morgan reproduction stuff available. It isn't FWD, but it should give you some ideas. There's also the 2CV Kit Car club out of the Netherlands that just has to have some of the info, if not the parts, that you are looking for:

http://www.2cvkitcarclub.nl/english.html

If you must have FWD recycled auto parts, several generations of Honda Civic were proper dual wishbone designs, but they sort of use a strut as well. They're cheap as dirt here, and you can get plenty of lightweight (and pricey) racing bits to improve the design.

Just some direction for your search, but try a little harder on the 2CV stuff. Your life would be so much easier with a complete unit, and that Citroen is a really cool one. It would be my choice for a vehicle between 500Kg and 750Kg. 

TomA


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## Woodsmith (Jun 5, 2008)

I like the look of wishbone suspension but the 2CV set up is prefered for simplicity and effectiveness.

However, I'm just not seeing any at breakers. There is a whole rolling floor pan on Ebay but it is a long way off and way more then I want to spend on it as it is essentially rotten.


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## MalcolmB (Jun 10, 2008)

You've probably already considered it, but it sounds as if a mini front subframe complete with suspension and disc brakes would fit your needs. It's simple, robust and spares are cheap and readily available. It can also be upgraded easily from the original rubber springs to coilovers. A subframe with suspension springs and arms weighs around 60 lbs (just weighed mine ). A motor can be mounted longitudinally, low down in the subframe, and the prop shaft could run underneath the steering rack, where the exhaust normally runs.

The most likely drawback I can see is that the suspension towers may constrain your design.


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## sunworksco (Sep 8, 2008)

Have you visited www.reversetrike.proboards.com
also www.locostusa.com


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## Duxuk (Jul 11, 2009)

Tom A's point about the torque steer of an FWD is a good point. It would make a direct steering link awkward or even dangerous. In defence of my own use, my trikes have been light, especially at the front and of course RWD.


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## sunworksco (Sep 8, 2008)

Reverse-Trike information.

http://www.rqriley.com/3-wheel.htm


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## sunworksco (Sep 8, 2008)

Mission Statement as of 9/09​Paid Membership (Member DVD available with trike files, images and videos)
Official Reverse Trike Discussion Group on Yahoo.com associated with this site (started 8/06)
Advantages of the Reverse Trike Design
My Personal Reverse Trike design ideas
Electric Reverse Trike conversion possibilities
Crossover Technology (technology from other vehicles that could be used on RT's)
Licensing and Regulations by State (plus insurance providers for RT's)
Marketing Concept for manufacturers
For Sale/Wanted Ads (Free Ads Section - Currently 8 Ads)
Motorcycling Truth (author unknown)
You Buy It - We'll Build It! (We'll build your kit and you ride it home!)


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## EVMAC70 (Aug 25, 2019)

Woodsmith said:


> The usual layout of reverse trikes seems to come in two flavours.
> Front drive with motor and transaxle at the front as if it were a front wheel drive car.
> Rear drive with mid mounted motor and transmission as if it were the back of a motorbike.
> 
> ...


HI Woodsmith, Its all about what you want sir. If you want optimum efficiency and light weight then driving through a long propshaft is not the answer but if you want rear wheel drive but dont want to have to sit right at the front with your 'sacfricial' legs then to keep the trike balanced and have rear wheel drive a propshaft is the answer. It also depends on handling vs fun factor, single rear wheel drive = more fun, front wheel drive = maybe a little tail happy when you push it but you can direct the power where you want it to go.
I grew up in the UK and drove front wheel drive cars with the exception of my 3 VW campers so I'm a little biased but I do understand if you grew up with rear wheel drive and know how to get you powerslide going it is a lot of fun, good luck and remember a properly balanced trike is what its all about no matter front or rear wheel drive try to keep the ratio of track width to wheelbase around 1:1.5 to 1:1.6ish, center of gravity as low as possible and equal weight distribution on each wheel with 2/3rds weight in first 1/3rd of the wheelbase ( some if it can go in front of the axle) and 1/3rd of the weight in the rear 2/3rd of the wheelbase.


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## EVMAC70 (Aug 25, 2019)

I forgot you should also try to keep as much of the weight as you can inside of the imaginary triangle drawn between the center of each wheel


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