Pro-Touring Trike - In Theory

[toddshotrods]

Moderators, if this is too far-fetched and you have to "file" it in the Outhouse, I understand.

I had a crazy brain fart a few days ago, did some surfing, found some interesting info, and now am more curious than ever about whether or not a trike can handle like a sports car???

...Rear engine Trikes sit on the road like a go-kart and if anything you can make them slide sideways or do donuts, but you can't make them tip over no matter what you do.

I have proven many times that our Trikes go faster around corners than any other motor-vehicle on the road today. On a tight corner race track no motorcycle or sports car can go as quick as a rear engine Trike...

He is speaking of a rear-engined, VW-based, trike. His theory is based on the fact that the COG is lower and much further back than a motorcyle based trike, and that gravity and inertia acting on this low rearward COG will cause the vehicle to rotate rather than tip - allowing it to corner so well.

IF this theory is sound, one would be able to build a transverse mid-engined trike, instead of the rear-engined VW type, and a relatively tight rear suspension - all designed to make the rear end rotate PREDICTABLY under power. Or would one end up taking an enclosed joy ride to the local emergency room

[pushrod243]

wouldnt you think a trike would have a tendency to understeer? Maybe you could install tractor brakes to make it turn better? And i bet i could flip one over i'm pretty good at testing a vehicles limits. Sometimes it hurts though.

[Marcus SC&C]

Don`t forget that trikes don`t have to have the single wheel in the front. They can also be "tadpole" configuration. There was an IndyCycle rep set up next to our booth at a big car show several years ago. Picture the front half of an indy car being rear ended by an 1100cc sportbike. The idea is that the wide front keeps it super stable and you`ll run out of rear grip and oversteer long before it`ll flip. I kept thinking how much cooler it would have been with a twin turbo Northstar and a single 345-30-19 in back. Marcus

[Bill Howell]

Todd,
I read this thread earlier today and have been thinking about it. All standard bikes that are converted to trikes ie. harleys,goldwings are midengine-right? Having rode for years and having had the opportunity to ride several versions of this type trike, I can tell you they all bite as far as handling goes. The problem with all trikes it there is no way to lean it in a curve, forcing you to actually turn the front wheel instead of just leaning enough to negotiate the curve. When you can not lean, it changes the center of gravity and really makes the turns awkward. To make things worse, most manufactures put two wide tires on the rear and a skinny out front for "the look". This makes turning at speed a real challenge and sometimes even dangerous. I know this is not a technical answer, just an explaination from someone who rides.
Bill

[TonyL]

as long as the trike had two wheels in front (tadpole style) it could work and has been done alot. having ridden many three wheelers (even flat trackers) i know one could never be made to handle well on a road. i've got the scars to prove it cant be done.

[toddshotrods]

Bill, I rode a converted motorcycle trike before too (yeah - that would be a true mid-engine design). I didn't like it at all. It was awkward, and there is no way I would have tried to push it around a corner. The guy I quoted above said that the converted motorcyle trike cannot corner. He said if you push it in a corner it will tip. Motorcycle racers call it a "high-side". At the very least it will push (understeer) and you'll be in the weeds, guardrail, etc.

He is talking about a rear-engined VW trike. It sounds like he is saying that you can use throttle-induced oversteer to compensate for the minimal front contact patch. That may sounds scary to those accustomed to conventional front-engine/rear-drive sports cars, but it is similar to traditional mid-engine driving techniques.

Usually, you CANNOT lift during "spirited" cornering in a mid-engine car. Doing so will usually result in a 180, 360, or a combination of the two in various quantities. I know this from experience. I remember reading an article when the Countach was fairly new. I believe it was in Road & Track, and it was a black one that was featured on the cover. They were testing it on a race track - big oval, I believe. They said that at speed you had only one option to get around the corners - stick your foot in the gas pedal! Anything else would mean a spin, trip into the wall, or both. They were commenting on how unnerving it was to push a $100+K (then) car in this manner, with a concrete wall waiting for them.

As for the small motorcyle front tire, don't forget that there is very little weight up there on the car-engine trike. Your front tire/contact patch requirement is dictated by the percentage of vehicle weight it has to handle. He points that out too. He says that the best handling trikes are rear-engined, with lightweight frames. I wonder what the actual weight distribution is - probably like 20/80 (front/rear)

Here's the articles:
http://www.trikesaustralia.com/trike_types.htm
http://www.trikesaustralia.com/live_to_ride_article.htm