Author Topic: guzzi reverse trike  (Read 647 times)

Offline gearman

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guzzi reverse trike
« on: March 18, 2018, 11:21:13 AM »


I am making a reverse trike on one of my converts.I am using the a arms and spindles from a Honda recon 250 atv. I have been studying for days to get the thing made correctly.I set the caster at 5 degrees.The ball joint alignment seems to be 10 built into the spindle.Nothing but toe is adjustable on the Recon.When I turn the wheel to full stop The camber changes from 2degrees to about 13. Wow .It has unequal length a arms and getting the  inner bushing  upper to lower spacing  is a question for me. Does any one have a 250 recon and a tape measure.The upper inner bolt ctc would be a start. This will work.proven ideas. Thanks










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« Last Edit: March 18, 2018, 11:26:41 AM by gearman »

Offline guzzisteve

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Re: guzzi reverse trike
« Reply #1 on: March 18, 2018, 02:19:01 PM »
Nice project. 
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Online RinkRat II

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Re: guzzi reverse trike
« Reply #2 on: March 18, 2018, 02:27:30 PM »
Quote
.I set the caster at 5 degrees.
If that's positive, great. You want as much positive caster you can get for best rolling resistance on the highway. Nice project! :popcorn:

      Paul B :boozing:

   Over the years I've used a lot of information from a book by Fred Puhn called How to make your car handle. Basics to full race setups, well worth it.
« Last Edit: March 18, 2018, 02:57:57 PM by RinkRat II »
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Offline gearman

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Re: guzzi reverse trike
« Reply #3 on: March 18, 2018, 05:10:44 PM »
yes it is positive. I can make it whatever I want. but at 5Degrees and turned full lock I have about 14 degrees of camber. The wheel is really flopped out.I know some Mercedes have a flopped out wheel when lock to lock.My car does not do that.It looks like a leaning bike.Any front end guys here?

Online rodekyll

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Re: guzzi reverse trike
« Reply #4 on: March 18, 2018, 06:02:09 PM »
Many vehicles increase caster as they come off center, similar to the flop of a m/c front wheel.  The Porsche 914 (iirc) looked like it was coming off the wheels at lock.  The effect is to reduce the turning radius when you're hard-over. 

There are a lot of front-end 101 write-ups for the DIY.  I looked into some designs and considerations when I was starting my trike project.  The complexity was one reason I decided to do a conventional trike for my first attempt.  The easiest way is to find a complete donor front suspension/steering and modify from there.  Otherwise you've got a long learning curve to understand the theory, and a few dry runs before you get it roughed-in.  If you expect it to all work on the first attempt you will be hugely disappointed.

Unequal A-arms have a natural relationship between neutral camber and the inboard pivot points.  With a given length to the upper and lower, the pivot points are predetermined.  Here's my trike's unequal a-arms.  Notice the angle of the vertical-ish struts.  That's the only place they can be.




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Online RinkRat II

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Re: guzzi reverse trike
« Reply #5 on: March 18, 2018, 06:22:35 PM »

   SAI or KPI are critical at the point you are stating as "Flop". When in full lock,  SAI can be compensated for to a small degree by camber settings but initial setup at a neutral point is critical.  :popcorn:

      Paul B :boozing:
A Miller in the hand is worth two in the fridge.

Offline gearman

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Re: guzzi reverse trike
« Reply #6 on: March 19, 2018, 06:01:18 AM »
Many vehicles increase caster as they come off center, similar to the flop of a m/c front wheel.  The Porsche 914 (iirc) looked like it was coming off the wheels at lock.  The effect is to reduce the turning radius when you're hard-over. 

There are a lot of front-end 101 write-ups for the DIY.  I looked into some designs and considerations when I was starting my trike project.  The complexity was one reason I decided to do a conventional trike for my first attempt.  The easiest way is to find a complete donor front suspension/steering and modify from there.  Otherwise you've got a long learning curve to understand the theory, and a few dry runs before you get it roughed-in.  If you expect it to all work on the first attempt you will be hugely disappointed.

Unequal A-arms have a natural relationship between neutral camber and the inboard pivot points.  With a given length to the upper and lower, the pivot points are predetermined.  Here's my trike's unequal a-arms.  Notice the angle of the vertical-ish struts.  That's the only place they can be.    You are correct, that is why I  am using a Honda atv  suspension.I can't stand another dissapointment.btw what is your oal width or your trike rear tires. Thanks  ps I did read ad nausium on the topic .




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« Last Edit: March 19, 2018, 06:03:48 AM by gearman »

Online rodekyll

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Re: guzzi reverse trike
« Reply #7 on: March 19, 2018, 01:15:37 PM »
Overall Length   106"
Wheelbase   72"
Track      50"


Gearman -- disappointment is part of the process.  It's going to happen with regularity.  There are no published answers to your questions, only clues and hints.  If you're doing it right you'll always leave a trail of scorched earth and charred parts in your wake.  It's all on you to make it work, make it fit, and make it go.  You're the only one it matters to, so you're the only one who cares.  It can be a real ego burn to know that there's nobody to blame but you, and it takes a particular mindset to go "awshit", back up, and make another run at it.  It took from 2013 till this winter to get my brakes to stop sucking, my fuel tanks to switch, and my cruise control to work.  I was six weeks just building the leading link front end.  There have (and still are) so many frustrations on this build that if I stopped dealing with them to count, I'd give up machinery altogether.

I've posted as many topics about my trike project failures as I have about successes, and after three years building it and two years riding it, I'm still struggling with some chronic issues.  Heck, just yesterday I posted that V2 of my dashboard isn't working the way I want it to.  I've got MONTHS into just the switch and gauge panel, and it looks like I'll be doing it again.  Yes, it gets disheartening.  Yes, some days I want to trade it in on a Miata.  And some days I can't suspend my disbelief that it's ever going to be as roadworthy and reliable as a Chevy.  If you can't deal with this reality, then your money will be much better spent on a turnkey trike.

But when I climb aboard and something I've been fighting WORKS AS INTENDED it's a wonderful feeling!  When I'm at a gas stop two time zones away from the barn and surrounded by people wanting selfies with the trike, it's great!  When I get that feeling I'm being followed, and then the follower catches me and says "I was hoping I wouldn't have to chase you to Portland to find out what that contraption is . . ." it's irreplaceable.  The other day I pulled up near the grounds machines at the farm supply.  The guy who'd been chasing me says "I knew you'd be coming here so that "thing" could visit his cousins."  I say "Yup, it's a ditch pump motor, all right."  He says "Sooo. . . .  is it British?"  I say "No, more like Hungarian with maybe some Greek."  "So you made all of it?"  "If you see it it's because I put it there."

Big eyes.

Priceless.  Makes it all worthwhile.

Offline John A

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Re: guzzi reverse trike
« Reply #8 on: March 19, 2018, 02:24:26 PM »
Rodekyll is right about this. when Bob Nolan was building his three wheeler I was able to help him by lending him a book: Automobile Fundamentals, Chassis and power transmission. copyright 1945. by Ray F. Kuns . in the section on front steering geometry there is a diagram on toe out on curves that may help you. look for a copy in old book sellers and Amazon.
John
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Offline gearman

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Re: guzzi reverse trike
« Reply #9 on: March 19, 2018, 02:24:57 PM »
rk,have you ever pushed it and lifted the rear wheel.Mine has a rear width of 51in. Thanks for your comments

Online rodekyll

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Re: guzzi reverse trike
« Reply #10 on: March 19, 2018, 02:37:04 PM »
Trikes don't want to fly a corner the way a hack does because of the symmetrical wheel arrangement.  In addition, I have Independent Rear Suspension.  IRS doesn't lift the way a solid axle does because it doesn't transmit forces from one side to the other -- at least not with the lateral forces I can generate.  Perhaps someone with stronger arms can push it hard enough to defeat the suspension. 

Online Rick4003

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Re: guzzi reverse trike
« Reply #11 on: March 19, 2018, 06:03:03 PM »
Hi gearman,

This looks like a good setup, I'm sure you can make it work well. As rodekyll says it is all about getting the geometry right on the suspension.

I find that much of the enjoyment in making a project like this is going through all the steps of designing, building, identifying the faults or mistakes and get it all working well in the end. I almost gets a bit disappointed if it just works right out of the box. Then what are you supposed to improve on if it just works? That's a bit boring :)

But please share your progress and thoughts on the project. It is always fun to follow along.

-Ulrik

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Online RinkRat II

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Re: guzzi reverse trike
« Reply #12 on: March 19, 2018, 07:00:38 PM »
 Gearman,
  In looking at your two initial pictures I believe that the geometry your using trying to use off road  designed parts is where the glitch lies. If you look at keeping the lower control arm parallel with the ground the A arm geometry won't allow for that. Good for dirt, not so good for street. Calculating roll center and A arm length  would be a start to finding the right set up. There are several on line calculators that will help you figure it out.  Your setup for the street should look similar to the Can Am setup.




       Paul B :boozing:

   Here's just one:http://www.speed-wiz.com/
« Last Edit: March 19, 2018, 07:04:21 PM by RinkRat II »
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Offline John A

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Re: guzzi reverse trike
« Reply #13 on: March 19, 2018, 07:41:52 PM »
Automobile Fundamentals Chassis And Power Transmission https://www.amazon.com/dp/B004UAAWNQ/ref=cm_sw_r_cp_tai_lCfSAbQZNGSQG

I wish I had a scanner, but this is it, a wealth of theory and practice . I'd encourage anyone that builds stuff to go on the road to have a look. First published in 1945 so it's modern but they had it figured out!
John
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