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Post by DaveJ98092 on Jan 12, 2015 2:08:35 GMT -5
Note. I did a number of corrections, additions etc. to the above post during the day today. Guess I got too much time on my hands. No one had responded yet so I thought that would be Ok. Come on guys, there is plenty of red meat here and the forum is sooooo... dead. Maybe this topic has been flogged enough? Comment on something else. Better yet start a new thread. Pardon me Dave while I step up on your soapbox.A forum is only as interesting as its members make it. If we all just log in every now and then without contributing what does the next guy see? Surely you guys have opinions, tech info, encouragement, criticism or my favorite contribution, simpleton B.S. Stop keeping it to yourself. Lets soup things up a bit. I think my SCCA comments got axed. This is just my opinion, anyway, I have not seen any 1F2R trike that could out corner a VW bug. Every one I have seen trys to tip over at any thing approaching 0.7G and that is why I got way from trikes back in the 80's. The only way to corner a 1F2R is to have enough power to spin the rear wheels so it can not hook and flip. Maybe a modern setup may do 0.8's but at what cost in suspension setup? A good setup 2F1R (reverse) could out corner it with ease. A well set up 2F1R will have no problems out cornering it and would probable be 4 laps ahead in a 10 lap race. |
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Post by trivetteguy on Jan 14, 2015 0:12:19 GMT -5
Note. I did a number of corrections, additions etc. to the above post during the day today. Guess I got too much time on my hands. No one had responded yet so I thought that would be Ok. Come on guys, there is plenty of red meat here and the forum is sooooo... dead. Maybe this topic has been flogged enough? Comment on something else. Better yet start a new thread. Pardon me Dave while I step up on your soapbox.A forum is only as interesting as its members make it. If we all just log in every now and then without contributing what does the next guy see? Surely you guys have opinions, tech info, encouragement, criticism or my favorite contribution, simpleton B.S. Stop keeping it to yourself. Lets soup things up a bit. I think my SCCA comments got axed. This is just my opinion, anyway, I have not seen any 1F2R trike that could out corner a VW bug. Every one I have seen trys to tip over at any thing approaching 0.7G and that is why I got way from trikes back in the 80's. The only way to corner a 1F2R is to have enough power to spin the rear wheels so it can not hook and flip. Maybe a modern setup may do 0.8's but at what cost in suspension setup? A good setup 2F1R (reverse) could out corner it with ease. A well set up 2F1R will have no problems out cornering it and would probable be 4 laps ahead in a 10 lap race. Long time reader, first post. I have always loved trikes of all kinds standard "deltas" and "reverse". Its not very often the Trivette and Bob Keyes 1F2R "delta" design is mentioned on most trike forums (or any other forum for that matter). The problem with most 1F2R trikes is, they use improper steering geometry, wrong weight distribution and engine positioning (aka reliant robin) and aren't designed from the outset for dynamic stability using three wheels. The late Bob Keyes (his last name rhymes with pies) designed something truly special, I had a chance to drive one of his original trivettes years ago and what Road Test magazine said was true, you could literally unstick the rear before the front! The oversteer potential is clearly apparent but somehow easily controllable with only one wheel guiding it around a turn. The government later tested it, and Bob said they couldn't believe how well it was designed. Bob's old site references it I think at www.vigillante.com/TriVette.htm I don't think we will see such a well designed track-worthy 1F2R trike ever again. |
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Post by Liteway on Jan 14, 2015 0:29:40 GMT -5
This guy built a trike, then eventually converted it to 4 wheels. I had some brief correspondence with him a long time ago and he said the 4 wheel vehicle is superior in every way... www.home.mride.se/I'm sure he may have been able to make the trike handle better if he changed a few things here or there, but in the end, even after making those changes it would still handle better as a 4 wheel vehicle. Not to mention the gains in acceleration with 2 tires putting the power to the pavement. If you gave a minimum weight and maximum horsepower allowed, then challenge designers/engineers come up with three and 4 wheeled vehicles to race around a track that has both tight corners and fairly long straights, I doubt the three wheeled vehicle would win. If you gave the three wheeled vehicle a weight advantage, it may be a lot closer. ...but then, what do I know anyway?[/ Well, you likely know something as you recently put a trike on the road that as demonstrated in your video, appears quite capable. Can give us an idea about rear tire size and weight distribution ? What of kind grip are you getting with full bore straight ahead acceleration? Incidentally , how is the body work coming? |
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Post by Liteway on Jan 14, 2015 0:54:31 GMT -5
I think my SCCA comments got axed. This is just my opinion, anyway, I have not seen any 1F2R trike that could out corner a VW bug. Every one I have seen trys to tip over at any thing approaching 0.7G and that is why I got way from trikes back in the 80's. The only way to corner a 1F2R is to have enough power to spin the rear wheels so it can not hook and flip. Maybe a modern setup may do 0.8's but at what cost in suspension setup? A good setup 2F1R (reverse) could out corner it with ease. A well set up 2F1R will have no problems out cornering it and would probable be 4 laps ahead in a 10 lap race. Long time reader, first post. I have always loved trikes of all kinds standard "deltas" and "reverse". Its not very often the Trivette and Bob Keyes 1F2R "delta" design is mentioned on most trike forums (or any other forum for that matter). The problem with most 1F2R trikes is, they use improper steering geometry, wrong weight distribution and engine positioning (aka reliant robin) and aren't designed from the outset for dynamic stability using three wheels. The late Bob Keyes (his last name rhymes with pies) designed something truly special, I had a chance to drive one of his original trivettes years ago and what Road Test magazine said was true, you could literally unstick the rear before the front! The oversteer potential is clearly apparent but somehow easily controllable with only one wheel guiding it around a turn. The government later tested it, and Bob said they couldn't believe how well it was designed. Bob's old site references it I think at www.vigillante.com/TriVette.htm I don't think we will see such a well designed track-worthy 1F2R trike ever again. The configuration does resemble the more recent 4 wheel Le Mans Delta Wing racer of Ben Bowlby. Love "out of the box " thinking, particularly when it works. I envy your experience driving the Trivette, must have been great fun. |
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Post by Liteway on Jan 14, 2015 22:34:06 GMT -5
Mine is 560/98 for 5.7 lbs per horse. Not really,I didn't get the bike's ram air converted to the trike. That is supposed to be good for 3hp at 100 mph, so actually it is 560/95 or 5.9 lbs per horse, I should fix that.
That weight figure does include 15 lbs of body panels. Our pwr/wt ratios should wind up very close to the same though yours will be less affected by driver weight.
You got it right. The kids are only young once. The trike can wait however long it takes.
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Post by tripod1 on Feb 17, 2015 6:48:05 GMT -5
I have searched the internet but can not find the answer, here is the question, All things being equal, engine, power, weight of vehicle, what would go round a track quicker, 3 wheels or 4? I'm not sure the answer will be out there on the web as so few folk have ever had the opportunity to compare like with like. In fact is it even possible to have a three wheeler of the same weight as a four wheeler that are in every other way identical? I suppose it is if you ballast the three wheeler to bring its weight to that of the four wheeler. It has been previously correctly stated (in my opinion) that some of the advantage of the three wheeler is lighter weight. This is probably the only advantage in regard to outright performance so once the scales are leveled the only advantage is lost and the four wheeler wins due largely to the other correctly described disadvantage of reverse trikes which is lack of grip when accelerating out of corners. But I am not sure its as simple as this. Assuming that the driver is not a guru of race driving or robot and is human I feel the three wheeler might well be easier to drive on the limit of adhesion. The single rear wheel gives a less blurry or confused signal to the seat of the pants and in my experience gives a degree of confidence about what the rear end is about to do or is already doing not always available in a four wheeler. This is now doubt due to the two rear wheels in a four wheeler having to effectively combine or average their data being fed to the drivers backside by way of the chassis. One wheel gives a completely clear picture of whats going on without averaging the grip at each wheel. In regard to grip when 'driving' out of a corner this is also less of a problem at greater road speeds like those experienced at proper race tracks rather than an autocross event where speeds are probably mostly under 60mph. Braking stability is also first class in a reverse trike by its very nature and I suspect trail braking quite hard right up to the apex is possible beyond what a four wheeler allows. I really haven't explored the outer limits of the Tri Pods braking capabilities at the track as that would require larger testicles than I possess (roll bar and harness's would need to be fitted first). You can brake very very very late though. I find the car steers a very straight line and is very easy to place making for consistent lap times and making it easy to work on your lines and find more time. I think it was also touched on that trikes might have an aero advantage which I think might be the case to a small degree but any car with outboard wheels has horrible drag. My car is very much designed for fun at sensible speeds on the road rather than being a track day weapon but as much as a four wheeler is ultimately the quicker car around a track (probably) I feel strongly that a well designed three wheeler can be a better drivers car. One day I hope to build a track special with ultra low CoG, wider track and super light and see what happens. Andrew. |
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Post by Liteway on Feb 17, 2015 8:33:22 GMT -5
Specs for Tripod please. Powertrain, weight, weight distribution, tires sizes, track and wheelbase.
846 am. At the Tripod website (yours Andrew?) tripodcars.com/concept.html there is link posted LJKS. This gives a unique and reasoned prospective into the advantages of 3 wheels. There is enough to digest that I intend to read it several times to get my tiny mind to absorb it all. I would urge all to read this. It is great food for thought and gives lots of fodder for this particular thread.
Of special interest to me was that what is good front end geometry on the front of a 4wheeled vehicle is not what is needed on a tadpole. The front wheel camber angles should be held the same as the rear wheel when cornering, not necessary at right angles to the road surface. Read the link for details.
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Post by tripod1 on Feb 18, 2015 16:31:21 GMT -5
Specs for Tripod please. Powertrain, weight, weight distribution, tires sizes, track and wheelbase. 846 am. At the Tripod website (yours Andrew?) tripodcars.com/concept.html there is link posted LJKS. This gives a unique and reasoned prospective into the advantages of 3 wheels. There is enough to digest that I intend to read it several times to get my tiny mind to absorb it all. I would urge all to read this. It is great food for thought and gives lots of fodder for this particular thread. Of special interest to me was that what is good front end geometry on the front of a 4wheeled vehicle is not what is needed on a tadpole. The front wheel camber angles should be held the same as the rear wheel when cornering, not necessary at right angles to the road surface. Read the link for details. Hi, We use a few different donor cycles. Originally (the prototype) used a Superhawk/Firestorm Honda V twin which I have enjoyed for 40,000kms, half with my EFI fitted as the carbies are a bit of a pest of a thing. Customer cars have Bandit 1250 and Honda Blackbird engine and swingarms fitted. With the other mild revisions made to the production kit the Bandit version drives very nicely. The Blackbird which I have only had a brief drive in hooks up surprisingly well for 155bhp and charges down the road with great authority. We have also used a few other donors as one offs for the moment. Perhaps the one I am looking forward to seeing running the most is the Yamaha FZ1 version we have sent to our US Tri Pod kit distributor in Colorado. Brian should have it together later in the year. All are 1800mm (6ft exactly) wide (overall), wheelbase around 2550 - 2600mm, weigh between 390 and 420kgs depending how they are built. Weight distribution is 62/38 to the front. Not ideal but maybe a pretty good compromise. The Tri Pod 1 has 15" wheels at the front - 195/50-R15 but customers have been known to fit wider and larger diameter wheels. Rears tend to be 205/40-R17 mounted on the donors original rim (which is usually 5.5"). Yes the website, the design etc is mine. The LKJ Setright article is typically Setright in that he sees things (or did, unfortunately this brilliant writer and brain is no longer with us) from a different angle than most. Worth a read a few times as I have but it is really only his surmise I suppose but I think it all makes good sense. In regard to this forum... I could never really work out why it didn't get going with a bit more of a bang as there doesn't seem to be another anywhere for RT fans. Annoyingly (sort of) the Slingshot forum seems very busy. I suspect the Slingshot is going to create a whole lot more interest in general RTs (I hope). Andrew. |
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Post by tripod1 on Feb 23, 2015 2:37:18 GMT -5
I'd like to meet up with your US distributor. I live in Colorado too. Can you please send his contact info? Thanks! Hi Mr Joker. Brian Ball Motorsports in Golden. He has a website and a FB page. I'd give him a chance though to both receive the kit and get a handle and a start on it. LA dock strikes are holding up shipment. He won't have the crate for another few weeks. I'll be over there giving him a few pointers in first week of May. Regards, Andrew. |
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Deleted
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Post by Deleted on Aug 4, 2015 22:13:48 GMT -5
I have read claims related to a 2-1 type trike being more stable than a 4 wheel vehicle but I would personally not commit to this even though I am a designer and builder of 2-1 conversions.
I will say however that a 2-1 is more stable than the old style 1-2 type conversions due to weight transfer and better steering design.
I find in my own designs roll over is not a concern, side skid is probably more of a concern along with one becoming a lawn dart.
I would be willing to concede a 4 wheel unit would hold a definite edge over any 1-2 design and probably a slight edge over the 2-1 designs.
I think most of the new commitments in the 2-1 design like the Polaris slingshot is mainly due to lighter safety and DOT standards in the MC classifications vs auto classification realm.
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Post by endeavor on Apr 20, 2016 8:27:02 GMT -5
I have done much in the way of prototypes and real world study regarding 3 vs 4. I have also read articles and clippings pertaining to others experiences. I will concede in general 4 wheels setup on the same frame same roll center same center of pressure and gravity will outperform a 3 wheeler in the 2-1 configuration. A 1-2 configured trike does not compare in anyway so that's out fairly quickly. The issue is plain logic. The best way for me to explain is to use what I call the triangle factor. In a trike the natural balance will be the approximate center of the triangle. If the wheel base width is 60" and length 68" then the balance footprint is approx 32". Now during deceleration the weight transfer is forward so the base footprint becomes larger and the triangle increases in stability however during exceleration just the opposite happens and the footprint narrows. Also the 2-1 configuration does tend to oversteer so this can be a negative. A 4 wheel vehicle uses a box configuration so if the footprint is 60" the base is always 60" however the roll center will vary as weight transfers from front to rear but in general it's easy to see roll is under better control. More important is a 4 wheel vehicle rear wheel drive will tend to drift and front wheel plow so oversteer or understeer but in general more controllable than in the 3 wheel configurations. My designs are all rear wheel drive so I have to use some tweaks to ensure the tendency is to understeer rather than oversteer. I admit I am confused as to why Polaris went to such extremes on their slingshot to engage rear wheel drive when it is a front wheel natural. Design and setup on a 4 wheel vehicle is in my opinion much easier than 3 the general layout is much more forgiving and easier to fine tune. But it's not my gig so it will be 3 for me thank you. Here is an article worth reading also which I assume most have read - www.rqriley.com/3-wheel.htm |
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Post by Liteway on Apr 20, 2016 10:16:27 GMT -5
At last a posting,and a reasoned and experienced one at that . Thanks Endeavor.
I would only quibble about one point, that tadpole trikes tend to oversteer.
My experience is in both off/neutral throttle and braking, the tendency is understeer, with oversteer only encountered under acceleration.
This makes sense to me, even in theoretical terms, as all roll resistance is at the front and the end with the most roll resistance (as in 4 wheel vehicles) is the one that pushes.
The transition can be very abrupt and extreme, but not unmanageable if you are ready and used to it. This is where sidestick steering (and handlebars too, I suppose,depending on their length) provide an advantage over a conventional steering wheel by allowing a quicker (less motion)input to correct.
In using a steering wheel with the 2f 1r config. and rear drive, I think a very fast ratio is called for. Less than a full turn lock to lock.
Prediction. A lot of Slingshot drivers will make backwards tours in the weeds and this will eventually become an issue.
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Post by endeavor on Apr 20, 2016 12:51:35 GMT -5
I would also concede to the fact over steer may be common under most circumstances as in applied power in a corner. In any case I feel it's bad and a person is better to drive off the road rather than back off , at least you can see what you are about to collide with. In most of the articles I read on over/under the opinions tend to vary quite a lot also.
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Mick
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Post by Mick on Apr 21, 2016 14:25:33 GMT -5
Well this has been a good topic, sorry haven't been around for a while, lost my workshop facility and other stuff going on but back with a bang now, I have read over everything that has been written and still I am at a loss to the answer to my original question so I am going to start a new post on lap times!
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Post by DaveJ98092 on Apr 22, 2016 1:08:37 GMT -5
Mick, I wish you luck on this search. It seems that 95% of all trike builders will only ride on the streets and NEVER do a track day.
But if you can understand French, do a search or go to their Facebook page and ask some questions of this reverse "RACE" trike: TWS Racing - The Wooden Stash Racing
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Post by noahkatz on May 15, 2016 21:09:52 GMT -5
Everything else being equal, 4 wheels will outperform 3 in acceleration, braking, and cornering.
But there's really no answer to the question because everything else can't be equal by definition.
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dain
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Post by dain on May 16, 2016 8:11:01 GMT -5
The only reason I'm building reverse trikes is to avoid extensive regulations that 4 wheeled production vehicles must adhere to as compared to "motorcycles". In normal conditions I agree that a 4 wheeled machine will out perform a 3.
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Post by DaveJ98092 on May 16, 2016 12:49:30 GMT -5
Lets see, in USA and Canada we do NOT have to pay a tax to drive our cars or trucks into a major city. Outrageous parking fees yes but no city tax. From what I was told, that is one of the pluses of a motorcycle in London, no city entrance tax.
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Post by endeavor on May 16, 2016 13:05:59 GMT -5
It there may be a change brewing regarding the classifications. 26 states are now reviewing a change to reclassify side by side type trikes as autocycles. From what I gather this is good as the change means the restrictions match a motorcycle with the exception no helmet is required. This move was sponsored by Elio and Polaris in order to eliminate the helmet requirement. It is a government operation however so who knows how it will actually play out.
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Mick
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Post by Mick on May 16, 2016 14:06:05 GMT -5
In the Uk the law changed in Jan 19th 2013, anyone after that has to have a full motorcycle licence to ride/drive a trike, before this they were classified as a car, ish?
Although they come under motorcycle classification(with a few changes) you do not have to wear a helmet but do on a motorcycle.
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