Custom Reverse Trike Builds and Other Custom Projects
front suspension taking shape.
Posted on
29
Jul
2009 - by
stevem In:
1 seater 250cc trike
we got the tabs made for the front suspension. its tacked in and i’m pulling as many measurements as i can to make sure they are in the right spot. better to measure 10 times and weld once. looking for feedback too. so comments are very much so welcome. good or bad. 
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TomA
August 5th, 2009 at 9:48 am
Nice, tidy work, guys.
It all looks very good. Your skills are obviously improving. I like how you have carefully eliminated as a problem the rather “free form” dimensions of the frame rails by making the suspension pickup ears just right for correct front end dimensions. Excellent job.
I have a couple of comments about bracing:
For this weight of vehicle, it is probably stout enough, but your lower arm mounts are quite long. They are subject to braking and bump loads there and would certainly flex and bend if there was relatively light contact with a front wheel, like bumping hard into a parking stop diagonally. Since there isn’t any adjustment on the arms, that would be a bad thing to have to live with or fix.
I would think an easy way to strengthen those mounts, and also brace the frame there, would be to weld a flat plate across the tops of the mounting ears, and then I would run a small tube from the top of that plate to your upper frame rail. Do that for all 4 lower mounts, and the whole front end would be tied together much better, and you’d have a really stiff boxed section that would much better support the upper shock/spring mounts from the top rail. Even better, angle those bracing tubes from the lower arm mounts toward each other, like an upside down V, so that they come together at the bottom of the upper frame rail, and then put the top shock mount on the top of the upper frame rail right there. That’s the strongest arrangement.
When you add the upper shock mounts, I would also use some kind of cross-member (could rise up some and be a little hoop-like to make room for feet) that tied both mounts together directly.The front would then really be plenty stiff and strong.
Generally, the small diameter tubing you are using is great for lower weight, and much easier to work with, but you really need a lot of short triangulated tubes to make up for the strength large tubes have. It isn’t a linear factor. A tube twice the diameter is far more than twice as stiff and strong. I’m thinking you need a bunch of bracing around the seat area, too.
Look at the late 1950’s Maserati Typo 59, 60 and 61 “Birdcage” chassis variants for inspiration.
So far, though, this looks really cool. Nice work, men…
TomA