Trikes vs. Quads
 

Why do people ride 3 wheeled trikes instead of 4 wheel quads? I can think of several advantages to designing recumbents as quads. Much more stable. Two wheel-tracks instead of 3, which would make avoiding potholes and broken glass much easier. I guess there would be more weight, but is the tradeoff worth it?

Quads are usually less stable- I learned from experience, and add more weight, need more efficient braking with that weight, (also 1 more brake & mechanicals- more weight.) more bracing (yes; more weight!), suspension usually needed or the whole frame flexes, legally not a bicycle around here.... not allowed a lot of places that bikes are allowed, ever walk a quad up a hill? :D

countersTrike

IMHO, It's the driveline. Two rear wheels makes for more non-standard bike parts. Less serviceable by LBS.

Another item would be less rolling resistance from 3 wheels than 4.

Also the tadpole trike configuration is quite able to stop quickly with just the 2 front brakes, even on a loaded tandem version.

To answer beelz question...
No, four wheels is not worth the trouble in a practical sense.

Although it has been done with the kit that connects 2 EZ-1 recumbents to the Crank-It fullsuspension quad off-roader. There are also lean steer trikes & quads.

All very cool, but few that are practical...AND cool.

That would be a Greenspeed! ;)

:D

This is the operative issue. IMO every other point made in CS's post is either over,under stated or outright false. With modern materials a quad can be made lighter, yet stiffer than many trikes or even bikes! There can not be any argument that a four point stance on the ground is 'less' stable than a three point stance unless other issues of design are also explained i.e. a quad with a high center of gravity will be less stable than a trike with a very low c.g. A Delta trike has the complexity of a rear end that needs a differential and other aspect pertaining to twin wheel axle. A tadpole trike has the complexity of a steering linkage. A quad has both! Commercially only trikes are currently viable but increasingly quad designs are being rolled out but they are not legally bicycles and that is the kicker.

H

You are all saying that 4 wheel bikes are not legally bikes but Rhoades Car's website says otherwise:

"Street Legal As long as you don't put a motor on the Rhoades Car, it's use is governed by the same laws as a regular bike. It's legal to drive on any road that an ordinary bike travels..."

And if Rhoades is wrong, and 4 wheel bikes are not legally bikes, what kind of license/registration do you need to drive them?

Rhodes is 100% right- "STREET legal...","ride on any ROAD", but I doubt Rhodes could be used on many bike paths legally. People around here are constantly gripeing to the newspaper (Letters to the Editor) about 1 or 2 racing bikes zooming by, and nearly hitting their strollers. Rhodes are not that fast- but falls right into the catagory of "those terrible cyclists" thanks to a small few 'Speed Racers' and are closely watched here.

countersTrike

No specific license. A landscaping business in my town has one with racks for lawnmowers, edgers, trimmers, etc., without anything other than a business license for gardening- nothing for transporting.

coountersTrike

I really do not know the legal ramifications of quad licensing, mainly I was trying to give CS some benefit of the doubt. If it is in fact true that quads legally are bikes why did he say they were not? So there is in fact now not a single thing in his post that I can agree with. One thing is for certain, legal bike or not, in many metro area's you will be dead meat trying to actually operate a trike or quad on the roadway.

H

I think a more pertinent question is why would anyone ride a trike? There's extra parts, extra bother, etc. But, when you look at the layout of those things, they are just so much more compact than a recumbent 2-wheeler. With the 2-wheeler, the rider either has to be above both wheels (makes it tall) or in between both wheels (makes it very long). With the trike, the layout is very compact and low, and so it makes a lot of sense. But when you go from the trike to the quad, you really don't gain anything you didn't already have. Stability may be a problem on upright adult trikes, but doesn't seem to be on recumbents, so you don't really gain that. It seems to me that any argument you could make for using 4 wheels would apply equally well to 5 or 6 wheels.

Perhaps another factor is that a trike can be built with a rigid frame with no suspension and all the wheels touch the ground. On a quad, if you don't have a suspension system, you can have wheels off the ground while just sitting there.

Here you go- quad:
http://www.youtube.com/watch?v=vYB7CpwxcUw

countersTrike

What??? Is there a question or a statement in your post? Bottom line, a trike has several advantages over a bike, recumbent layout or not. However dynamic stability is worse than a bike unless the track is made wider than the current 28" - 32". A quad with a 32" track front and rear would be more stable than a trike with the same track, period. However that additional stability will come at the price of some additional weight and complexity. But how much does a wheel assembly weigh these days? How much would the extra suspension pieces weigh? The additional complexity, labor and design are what make quad designs so much more expensive and since trikes have 85% - 90% of what make a quad a nice thing to have many commercial fabricators stop there and concentrate on trike designs. The home builder can and IMO may as well go the rest of the way towards 100% satisfaction.

The width of a trike and quad are what make them unlikely candidates for wide acceptance in metro areas. I have, however seen with my own eyes a trike in Downtown Salem, OR. Seemingly without any effort he left me in the dust on my bike and cruised easily through the traffic with what seemed like only a few pedal strokes compared to my wild spinning. That simply would not happen on the East Coast. The motorists would have been too busy trying to run him off the road to notice that he was quite easily maintaining the prevailing speed of traffic.

H

People do ride 4 wheel quads. You may not have any where you live, but It's a big world out there.

Each extra wheel slows down the vehicle and adds complexity and cost. You don't have to balance a trike like a bike, so the extra wheel on a quad is more of a drawback than a benefit. Three wheels give you what you want with one less wheel than a quad. No reason to add a fourth.

And some people are afraid of heights. :rolleyes:


???!

What I'm saying is,...everyone's different.
Some folks can handle a trike or quad in any urban environment with out becoming road kill.

A year ago last October I was featured in an ad campaign by PG&E in San Francisco.
I was pictured riding my Challenge Hurricane 2 wheeled recumbent in city traffic down in the Financial District. I was between the trolley car rails and had a car behind me.

The rest of the poster was bright green with big white words reading ... GREEN IS THIS GUY!

Weeell, some of the SF locals got on a blog and berated SF & PG&E for trying to greenwash the city!
Went so far as to say I was about to get run over by the car. :eek:

What numbskulls! I just PASSED that car!! :D

I have no trouble operating in urban environments. Diamond frame, 2 wheeled bents, 3 wheeled bents.
I just take my legal "car space" and drive like a motorist, stopping at stop signs, signalling and being
AWARE!

I also use blinkies & a safety flag on the lower slung vehicles.

Isn't having two wheel tracks instead of three a reason? What do you do on a trike if you're approaching some broken glass? Very hard to avoid on a trike, I would think. Easier on a quad.

It is, but it's not very important.
The trade off is not worth it.
If you see it in time, you can avoid glass on a trike. You can always stop and go around it. I go around glass on a trike every week in the summer. I don't even think about it. You can miss many things by having it go between two of the wheels when you get used to it.


The extra weight and the wheel is not worth it. It's another thing to make it more work all the time. A trike is slower and heavier that a bike, a quad is slower and heavier that a trike.
The reason bicycles are so efficient is the fact that they have only two wheels. It's a big deal.

Only partly true. The trike is arguably heavier and more complex than a bike but a quad is only trivially heavier and more complex than a trike. Trikes are slower than bikes not because they are heavier but because they will roll over if they attempt to corner at speeds that are commonplace for bicycles. A quad is somewhat more resistant to rolling over than a trike of the same track and therefore would be faster but not as fast as a bike. On a straight run however both trikes and quads could be faster than a bike and if width were not an issue and the track extended to say 56" or 58" both trikes and quads would be much faster overall than a bicycle as their cornering speeds would be much higher than anything one could attempt on only two wheels.

H

Adding a fourth wheel would do absolutely nothing to improve cornering over a good tadpole trike. Regardless of 3 or 4 wheels, the trick is to get the pilot's COG down low enough.

I have a Vision Convertable (SWB or LWB) that is easy to change out. I'm 62 and still like to ride but it is harder to keep my balance at lower speeds or to start off from stop lights. I have been considering a trike or quad because of stability. So far I have looked at the Lightfoot and the Rhodes Car. Any other suggestions?

My favorite is the Greenspeed line.

So far I have a GTX and a GTT, but am still looking for a good deal on a GTO.
I have diabolical plans for a GTO, if I can find one within budget.

BULLS#IT. Trikes can easily outgun a bike through any corner they wish. I make up time on bikes through corners! If you're rolling a trike trying to keep up with a bike around a corner then you obviously shouldn't be riding a trike. Do you even own a trike?
The best example I can think of to back trikes over quads is to take a page out of motorsport. The trike is the F1 car, cornering flat, braking late and accerlating full boar out of a corner. The bike is a MotoGP bike braking early, accerlating gradually out of a corner then using it's amazing power to weight to blast down a straight @ 330km/h+ . Well guess what? An F1 car is 14+ seconds a lap faster then an MotoGP bike around ANY circuit they test at. Fact. And you can bet it's all via cornerspeed.

As for the a quad cornering faster then a trike. Well depends really, but I race faired trikes on a regular basis and the fastest vehicles through speed traps on corners are always trikes. Greenspeed built a fantastic quad and raced it quite successfully a couple of years back, yet turned up to the same race a year later with a custom trike, citing cornering ability as a reason to race it over the quad. Sure enough, they were easily the fastest through the hairpins on this circuit. Quads are useless with trikes around.
A trike will beat a quad because it weighs less and has less cross sectional area, thus less resistance. A bike will beat a trike because it weighs less and has less cross sectional area, thus less resistance.

You have no actual evidence to support these therories you've magically dug out of your head. If you wanna go and ride a quad then feel free, but please don't shove your ideas down people's throats. I will stick with my trike, bike and HPV thanx ;)

LOL! I ignored this thread for a while since I know nothing and obviously don't care about quads- except go carts which corner pretty well, but are illegal, and I tipped right over and fell on one of those bolt-up quads- hence; 'experience', as well as comments 'usually' or 'may be....' I said earlier.

The mindset of trikes not cornering well will go back to the older granny style trikes in the '50s, or maybe the Harley-Davidson choppers in the '60s that were engineered only for straightaways. Those did tip over a lot- unfair to use these stereotypes for all trikes with innovations over the years. Trying to convince much of society will just be like explaining ergonomics to an eel.

Physics, space frame technology, height, appropriate "even" balance, focusing on where sideways weight goes gets compensated with technology; which pretty much introduced tadpole trikes; much like slot cars doubled in speed using aerodynamic 'wing' cars that handle cornering weight on front wheels.

Of course, just piddling around a 5 mph (I fell @ 7 mph on a quad) is fine with a quad, granny trike, whatever!. But watch out for those joggers with 3-wheel strollers.........

countersTrike

I KNOW this, and said so. An F1 car however has a wheel track that is immense compared to the typical HPV. I joined this discussion only to 'respond' to ideas based on wife's tales. It's the "absoluteness" that you and another poster feel in your opinions that bothers me. Trikes make great racing machines, no doubt but quads exist for a reason, even if you don't think there is any need for them. Trikes are compromises between speed and stability. For the trivial weight of an extra wheel and some framing one can have both in a quad and tell me why the quad should have any greater frontal area than a trike.

I could take the front boom off my KettWiesel and replace it with a modified boom that incorporated two wheels, suspension, and new pedal/drive system... But what would it give me?? My high speed cornering is fine as is and I can max out the top speed as a Trike. There is no use for a quad solution when compared against a modern road Trike.

I do understand there have been some quads build for xc and downhill but many of the mountain bike trails I have used were only wide enough for a single bike anyway.