Getting Closer to Starting!!!

[Shadow Dreamer]

Ok, on the advice of an engineering friend of mine, I'm posting what I think are my "final" designs. He's looked at them, and thinks they're going to work just fine, but told me to post on a trike forum where others have built their own trikes.

Background information:
For a power plant, I'm using a 2.5l Iron Duke out of a 1984 Pontiac Fiero. I dropped the cradle, engine, trans, drive train, axle, basically everything on the cradle. Using the cradle as the starting point, I'm going to build the frame around it. I got the idea from Conrad Lawrence (aka Onetonmagoo on Youtube), who has also given me some pointers on the frame. I plan on using 1.25" x 0.125" 1020 CREW DOM tubing, although I'm also considering higher grades. I plan on using a girder fork with bale front end. For the neck I'll be using 2-3/8" x 1.5 (ID) x 7" CREW DOM 1046 piece of tubing honed out to take a Timkin cup and cone bearings 07100 & 07204. The triple tree plates will be made of 1" x 3" x 7" 1020 cold roll plate with a grade 8, 1" bolt connecting them through the neck.

In the drawings below, I've color coded the various tubes for ease of reference, and left out the 3 cross members in the side view that are towards the front end, as well as 2 of the supports (green), but show them in the top-down view for reference. The drawing are to scale, based off of photographs and measurements of the cradle after having removed it from the Fiero. Scale is shown in both drawings, but 1 colored square equals 1".

I would greatly appreciate the thoughts and comments of anyone who has built their own trike or has any experience with tube welding. I do plan on using a fish mouth jig for all junctions. Thanks in advance!

~SD

[FuzzyWuzHe]

Looks good to me ... but I'm not an engineer. Looking forward to another bid thread.

[Gorilla]

Nice to see a project coming together

[peteg59]

As a former Pontiac Fiero owner I can say without hesitation that the 2.5 engine is not very durable.
I put 2 of them in the car my wife drove, in under 75K miles. She literally drove it like Granny, & never hotrodded it.
They don't like running hot. Nor do they make lots of power in stock form.
The v6 Fiero, 2.8? engine was marginally better, but not sure of its longevity either.
The frame design you show looks very good structurally, although I'm not an engineer.
Good luck on your build
Hope that helps...

[Shadow Dreamer]

As a former Pontiac Fiero owner I can say without hesitation that the 2.5 engine is not very durable.
I put 2 of them in the car my wife drove, in under 75K miles. She literally drove it like Granny, & never hotrodded it.
They don't like running hot. Nor do they make lots of power in stock form.
The v6 Fiero, 2.8? engine was marginally better, but not sure of its longevity either.
The frame design you show looks very good structurally, although I'm not an engineer.
Good luck on your build
Hope that helps...

ALL input helps, peteg59. Also, are you aware, the early Fieros with the 2.5l in them had elongated dip sticks to the point that they would always show they had enough oil in them? This is a problem that was corrected with the later models, when they moved away from the Iron Duke. I actually specifically chose this model/engine for the Duke, as it was one of the last solid, iron engines produced by GM. They ran it in so many vehicles from the early 70's well into the mid/late 80's.

Right now my biggest concern is the frame. I know the drawings I made are really rough and aren't in 3D (I've tried using CAD software and gave up after 3 straight days of headaches). I'm just hoping that someone else out there who has built a trike completely from scratch will see anything that I may have missed.