2F/1R rollover tendency > Solution?

[Nutz4sand]

I like things that are different and all but at the same time I do not see this being what you hope it will be but at the same time I would find it interesting IF you can do it and build it and make it do what you say. 

I am not sure how you think the limited slip will keep it from getting to squirrely. Explain please.

The 3 wheels on different parts of the road surface VS 4x4 vin the same tracks is relative to the terrain. IF you are pushing crap out of the way (slush or loose mud) and riding up on something you may have less traction VS the front tires clearing the path and the rears following in the tracks. At least in a straight line.

3wheeler with single rear wheel driven does well off road? Got examples? I will try to find it on youtube next time I go to the library (no high speed here) I have seen JUST the opposite with that nitemare reverse three wheeler that was a complete flop.

If you drive the rear off ONE front it will try to speed up faster while turning one direction and slow down and drag while turning the other as which ever wheel goes faster or slower as its on the outside. This alone will make for a handling nitemare. Be VERY interesting if you can make this work.

Good luck.

 

[Boostinjdm]

Dude, everybody likes to dream a little.......time to return to reality.

[fabr]

I'm talking about all wheel drive, all the time. One front and the rear wheel are directly coupled, the other front is independently driven, but through a limited slip. The ratios are all identical, unless I slightly overdrive the rear, common in 4WD vehicles. The limited slip will prevent the steering & handling from getting too squirrely.

The 3 separate wheels are all seeking traction on 3 different parts of road surface. That is an advantage over trying to get traction on 2 parts of road surface, just like a 2WD limited slip has advatage over a single leg differential 1WD. Even in slushy ruts or wallows where front wheels both lose traction the single centered driven rear would be on higher & drier ground, getting traction. Many 3WD do very well, even offroad, with only the single rear wheel driven.

My front drive will be the nearly stock Dodge Omni setup, but limited slip to give traction to both front wheels. The rear will be driven off one front. Disc brakes on all 4, with those made for a car weighing 3 times as much, so killer brakes.

I am building for several reasons, first because I want to. Also it is cheapest to register and insure, as a motorcycle, plus I beat all SMOG regs, very important here in California. I can easily build the whole machine for way under $1,000. A stock Omni can knock down 41-44 mpg easy, at around 3,000lbs or so. I figure on something like 75+mpg with 1/3 the vehicle weight & good aerodynamics.

It will be a multi-use vehicle for most any road surface and moderate offroad, and should be good in snow, sand and mud. It will have extreme acceleration, crazy top speed if I wanted, very aggressive handling, excellent for the steep & twisty mountain roads here. It could pull my small popup trailer for long trips, with incredible mileage. It will seat 2, look good, handle great with incredible  acceleration, handle most any terrain and all with far more than good mileage and be exciting to drive. Complete parts cars are readily available for $200-$300. The tranny I'm using is a direct boltup to the VW 4 cylinder diesel. I've got a spare turbo and can intercool it and have strong power & torque, and bring the mpg's up around 100mpg if I drop in a diesel.

I can't see any reason NOT to build it 

This is why it won't work as you want.

[JimmieD]

Okay, let's see here: the single rear drive was used on all the early 3 wheelers in England, such as Morgan. In trials & rally events a 4 wheeled vehicle couldn't come close to the performance, this was for over 30 years. I imagine all the 4W had a single leg diff. So it can perform, depending on where & how it's used.

On the 3 driven wheels, I'll have a limited slip in normal FWD differential. One half-shaft driving through to rear wheel, with an in/out disconnect, that rear wheel drive can be selected offroad etc. but not necessary on pavement.

With selection of powering rear wheel offroad or in snow/sand the vehicle has traction on 3 different road surfaces, not 2, so quite likely better traction overall. Many 4WD are actually 2WD, one front and one rear driven, with open diffs selecting power to wheel with LEAST traction. In this setup it's more similar to a locker front diff, and more of a constant 3WD, or selectable to semi-locker FWD.

Handling would be similar to a 4WD with lockers front and rear, with possiblility of rear wheel getting squirrely on turns, don't know. However the rear lockup is selectable, allowing change to FWD only but as a limited slip [almost locker] front. Planning a wider tire on rear to help balance traction. 3 wheels driven is intended only for offroad use, otherwise 2WD L/S with Oxlock.

"If you drive the rear off ONE front it will try to speed up faster while turning one direction and slow down and drag while turning the other as which ever wheel goes faster or slower as its on the outside. This alone will make for a handling nitemare. Be VERY interesting if you can make this work. "

I don't think it would be any different than any FWD vehicle with a limited slip like the Oxlock, which still allows differential action instead of full locker. Oxlock can be made more agressive or gentler lockup, I think by changing springs. The pto disconnecter for rear will be my own design.

The 3rd driven wheel in rear will only be used offroad, or going slow in sand or snow. I don't foresee any problems, may be some, but I guess it's hide & watch. I don't have all the answers because it isn't built hah!

Main thing I wory about is flipping it when driving real hard on twisty roads, but low COG and wide-spaced front track may prevent that.

[Nutz4sand]

Okay, let's see here: the single rear drive was used on all the early 3 wheelers in England, such as Morgan. In trials & rally events a 4 wheeled vehicle couldn't come close to the performance, this was for over 30 years.

I have heard this before but you know what? I STILL do not believe this and till I could drive them both myself I will believe it was rigged rigged rigged.

Somebody was likely paying for those results.

If three wheels were faster you would be seeing them raced today at top levels AND YOU DON"T! For a good reason I bet. 


As for your project you are sorta pioneering a couple things that may have been daubled with by a few and you may make it work and I hope you do honestly. But you do face a few challenges and it seems to me there are a few things you are either overlooking or pretending will not affect it or will affect it in some different way they many of us here seem to think it will operate.

As mentioned before I like things that are different and its guys who go try odd off the wall things are sometimes the ones that do make some neat discoveries. And I do mean it when I say I hope you do. But I will also admit I am a tad skeptical of some of the claims you make. But look forward to seeing if you may be able to do just what you hope. It might lead to mprovements we can lop onto future thing here. 

I have seen a lot of things that work today I would not have thought would work and thats why I think you should try this. Till its built and tried we won't really know. Just theories I guess.

But I would still like to see thiose famous three wheeled Morgans beat anything today with four wheels. Till then its a bought and paid for result in my on those. 

[fabr]

Ditto.

[Boostinjdm]

dude, coupling the rear to one of the fronts is going to be a problem unless...you run a spool instead of a diff, or you use something like the honda tranny I mentioned that drives the rear off of a neutral source.

If you run a spool, you will have turning issues.  If you go with a different tranny, you have to locate one.  It's kind of an either/or situation. 

[JimmieD]

"But I would still like to see thiose famous three wheeled Morgans beat anything today with four wheels. Till then its a bought and paid for result in my  on those."

Who said anything about racing a 1930's Morgan against a 2010 vehicle? Show me an original 30'-40's 4 wheeled race vehicle that could compete against a stock, out of the showroom 70 year newer car of today? Not a chance. That wasn't the point of what I was saying. Simply saying that under the right conditions even a single rear wheel driven 3 wheeler could, could, out perform a single rear wheel driven 4 wheeler, under the right circumstances, that's all.

Maybe y'all are misunderstanding my use for this vehicle. I'm not planning anything but slow, casual, offroad driving, in 3 WD when needed, or sensible driving on the paved roads, sometimes in snow, with some times of pushing it hard on pavement. It's also super-economical daily transportation. Not building a race dune-runner or anything like that.

Fact is, I only mentioned it here because there's no other good forum with guys building one-off personal design tube chassis rigs. Very few build 3 wheelers except from tab A, slot B kits so there's not even any chat out there about them.

"dude, coupling the rear to one of the fronts is going to be a problem unless...you run a spool instead of a diff, or you use something like the honda tranny I mentioned that drives the rear off of a neutral source.

If you run a spool, you will have turning issues.  If you go with a different tranny, you have to locate one.  It's kind of an either/or situation. "

Nope, no problem at all. Not going to run a spool. An Oxlock isn't a spool. With a limited slip in the direct-coupled front/rear drive, and a limited slip in the front wheel drive differential, no problem at all.

There's lot's of other unique features in the design so that with it all put together right it will do just exactly what I intend it to do. Safely I hope, as far as pushing the 3W configuration hard, and that's what the original question was about. I already know the design will work just fine.

Thanks all....

[Boostinjdm]

The only REAL good way to connect different tires like this would be to drive each with a CVT. Or at least the rear with a CVT. Then it could adjust some.

I was actually thinking of the civic wagon tranny with a bike's shaft drive rear tire.  Get that ratio right and you're done.

[fabr]

There's some friction  starting here. Step back guys and take a breath.  So far I have seen suggestions and skepticism in this thread  . This type of thread is ,IMO, a great way to get ideas discussed. Lots of good things come from threads like this. Now back to the topic. 

[fabr]

With 2 offset wheels under power(1F,1R) the vehicle thrust line is skewed instead of parallel to the direction of travel/centerline of vehicle. Nasty things happen.

[Nutz4sand]

I would have quoted you Grimm reaper Racing but I kept timing out with a "fatal error" that I think is due to my wonderful dialup out here in the boonies.

You can say my idea of driving the rear tire with a CVT is an opinion but I would ask of you or anyone to show a better system that senses load requirements and applies power?

ESPECIALLY at the cost it would take to rig up a decent CVT. 

I do see what Boost is talking about if I understand right. He is talking about the Toyota wagon tranny (also used on sedans) with the all-trac (Toyotas AWD system of yesteryear)  and to run a shaft back to a shaft drive motor bike kinda of gearbox. Very good idea indeed. Quite possible the only one able to compete with or beat the CVT to the rear tire idea.

But unless a system could like these two above allow slip to the rear tire at the right time this proposed machine is gonna be so SQUIRRELY it will need to be fed nuts! (no not NUTZ) See Fabrs last post. He knows!

Sorry about the "Friction" partz.   

[JimmieD]

Thing is, I have studied this design in extreme depth for several years now, miles of research. Also machine design and vehicle design has been a major part of my life, an obsession, for a really long time, I'd give anything just to remember the stuff I've forgot hah!

On the 3W versus 4W:  Just like the gasoline engine versus diesel engine, there were powerful forces working against 3W's, because 4W were the big kid & had the dough to squash them. In many cases the reason 3W never made it big time in racing is because of that old dirty low down trick you guys know so well: THEY WROTE THEM OUT OF THE RULE BOOK! If ya can't beat 'em, force them out of the the competition!!

If you do some research, and that's real difficult 'cause not a lot of info on the net, you'll find that the 3W's beat the stuffing out of 4W's in the trials and rally racing of the 20's to late 30's or early 40's England. At the war many changes occurred and few performance oriented 3W companies survived. In Europe & England they've been common up to the 70's, like the weird Reliants, but only for ultra-basic transportation. For a real eye opener, check out the assortment here:

http://www.3wheelers.com/azlist1.html

Most were low-powered cycle types, to beat tax & registration fees and for people driven to poverty by the war. Development of hot machines was near zip because the base vehicles offered lousy drivetrains with cheap, weak components & junk design layouts doomed to failure. That put a lot of leverage against them succeeding as a major player.

In addition the talk of them flipping over, possibly started by the 4W competition, cuased a lot of people to shy away regarding competition etc. Funny, as mentioned by someone else, it's pretty darned hard to find reports of that actually happening! Hmmmm.....

[JimmieD]

Now, regarding my design, there's some problems explaining it all here. Several features are very different, and I hope/pray to generate some patents. Once a few things were figured out after a lot of head scratching, component designs were done so they could be built anywhere with absolute minimum tooling, be super simple mechanically, totally user/owner maintainable with minimum skills, resources & tools, be compact, light weight and useable over a large number of platforms.

Example: transmission design that can be easily built in a shop, if ya had one, with only a drill, cutting torch & grinder, with exception of one component that's already available off the shelf and very cheap. Tranny can easily handle 300HP+ with very light tranny weight, bullet proof, 'full synchro' without actually having synchros, shifts almost as easily as an automatic, requires no clutch on the engine, plus it's dual range and requires no trans lube.

My Limited Slip designs & layout for rear drive & L/S differentials are similar: stone simple, rock solid, stupid easy to build, costs pennies to dollars to manufacture compared to what's now available.

I'd love to tell the world, but CAN'T until the patent stuff happens! That's really hard for po' folks like me.

So, sorry if it all sounds like I haven't got a clue what I'm doing. Fact is I have it all designed 300% and know how it will work, just can't post it on the internet and give away 20-40 years of design work.

Thanks for understanding. 

[fabr]

C'mon guys.. Let's talk about the concept.AS for me I think only front wheel drive is practical. One reason for the demise of 3 wheelers was the need for a full size rear seat.If only 1 in back it would be severly unbalanced.