Preview: 'underbite' springer concept

[Dr. Tankenstein]

Here's one of the 'experiments' I'm working on in the 'lab'.
I wanted to combine a triple tree with a springer. I've seen a couple of custom fabbed setups, but nothing really had the look I was going after. Plus, I wanted to share my warped vision with all of you! :mrgreen:

This fork will go on a chopper-type build, so the main fork will be too long to mount the Monark springer (my favorite)traditionally.
So, I thought, why not mount it to the bottom tree? The bracket is an old UPS mount (compliments of my IT server friends). This setup also permits space to see the headbadge and/or install the headlight.

Still not sure how to attach it to the fork. I'm thinking of using a star nut or, since the steer tube isn't cut yet, I may remove the bottom bearing race and install the bracket and slide the race back on.

NOTE: Since there isn't a wheel mounted yet, the rockers aren't in the proper position. When held parallel to the ground, the springs snug up against the bracket, I'm now searching for some small 'rebound' springs for the section above the plate.

So, here it is, codename: underbite

Cheers,
Dr. T

 

[OUTLAW]

doc, looks like it should work. guess all ya can do is try it. great thinking outside the box. I get tired of the same old thing all the time. keep up the concept. I like em UNDERBITE.


Outlaw 8)

 

[XC204]

I like it ! I see what you mean about needing some replacement Springs :lol:

 

[Dr. Tankenstein]

I like it ! I see what you mean about needing some replacement Springs :lol:

Yeah, dogdart was nice enough to send me one of them. However, they must have used different springs throughout the years (maybe one is from a girls bike and the other from a boys ,dunno). I'm gonna use them through the mockup stage and make a decision on them later.

The design 'issue' I have now is, due to the extended dropout on the triple tree fork legs, the springer doesn't sit parallel to the main fork. It slopes backward quite a bit. Aside from the aesthetics being unacceptable, I'm concerned that the angle may bind and damage the Monark piece. Looks like I may have to get a custom bracket machined.

If I draw it and source the material, do I have any volunteers to cut out the blank? :mrgreen:

Cheers,
Dr. T

 

[Philphine]

i've been kinda thinking about that on a occ/wcc hybrid i keep threatening to start.

i've been thinking make a plate with the shape of the wcc's lower triple tree, but with the space added for the front springer section (in my case the forks off the occ). then bolt it to the bottom of the wcc tree and go from there, if that made sence.

 

[SCHWINNRAY69]

So that's what the Doc's been up too :mrgreen:


Looks great, keep us posted on it I'd like to see it with a wheel :wink:

 

[Dr. Tankenstein]

I'd like to see it with a wheel :wink:

Yeah, me too!

I'm playing around with some new top bracket ideas and researching different rocker designs. The Monark rockers aren't gonna cut it.

I'm looking for a set of rockers off a Spaceliner-type rat trap or some off a Higgins beehive. If anyone has some that they are willing to trace for me, I can fab them myself.

Cheers,
Dr. T

 

[pick]

How about something like this for your spring idea. A porch spring:

Then cut out the center rods & go to an auto parts store & get freeze plugs the proper diameter to fit the springs like so:

Drill holes in the cups for the center rods. These springs are pretty stiff, but might be just rite for a longer fork. Just an idea that I got from another member on here when I was workin on a monark springer. May or may not be what you are needing.

 

[Dr. Tankenstein]

pick,
DUDE! That's a brilliant idea! I'm headed to Home Depot later anyway, I'll pick up some of those. I think it was Uncle Stretch that gave me the idea of using the freeze plugs to cap them off, but I had forgotten what they were called......until now!

Now if I could only figure out the rockers :x One of the problems is, the frame isn't finished yet. I need to get it figured out then put the wheels on so a can set the triple tree fork length. Then I'll be able to dial in the springer position and the rocker design. Gotta be sure my feet don't rub on the front wheel when turning.

Man, I do LOVE figuring this stuff out! :mrgreen:

Cheers,
Dr. T

 

[gcrank1]

Try some auto/truck valve springs.

 

[Dr. Tankenstein]

Bought a set of the porch swing springs. They are pretty hefty, 325 lbs carrying capacity each! I haven't measured them yet, but they are definitely long enough, I may be able to cut them and make small rebound springs as well.

I'll post an update ASAP.

Cheers,
Dr. T

 

[pick]

pick,
DUDE! That's a brilliant idea! I'm headed to Home Depot later anyway, I'll pick up some of those. I think it was Uncle Stretch that gave me the idea of using the freeze plugs to cap them off, but I had forgotten what they were called......until now!

Now if I could only figure out the rockers :x One of the problems is, the frame isn't finished yet. I need to get it figured out then put the wheels on so a can set the triple tree fork length. Then I'll be able to dial in the springer position and the rocker design. Gotta be sure my feet don't rub on the front wheel when turning.

Man, I do LOVE figuring this stuff out! :mrgreen:

Cheers,
Dr. T

Not really an original idea! I think I got it from Petrohead, a while back when I was workin on a Monark springer with shot springs. You are right, they are pretty stout, but it looked like you needed the length. I got the springs & freeze plugs, but haven't gotten any further with it. BTW the freeze plugs that fit my springs are Dorman #555-033 & they are just a hair shy of 1 & 5/8" inside diameter & fit my springs perfectly. If you have the same springs, that may save you some time at the parts store searching for the rite size.

 

[Uncle Stretch]

Hey DrT I'm pretty sure it was originated by John Brain.

http://bikerodnkustom3.homestead.com/brainfork.html

 

[pick]

Hey DrT I'm pretty sure it was originated by John Brain.

http://bikerodnkustom3.homestead.com/brainfork.html

I think you pegged it Uncle! 8)

 

[jerrykr]

I'm not really sure about this, but I think those springs are designed to stretch out (longer) and return to their original length, vs the compression springs that that you want to use, (compress to shorter and return to original length).

I guess you will be able to report which way they work soon.

Hope they work for you.

.

 

[Uncle Stretch]

If you look at the holder thing , it has hooks and they squash not get longer. Ok They compress. I used them on my springer and they worked good. If you check you can get the freeze plugs in brass for about the same dollar or two a piece. They might look cool polished all shiny gold.

 

[Dr. Tankenstein]

That Brain fork is pretty close, mine will be considerable shorter though and 'slightly' different (if the brainfart I had today works out).

This upcoming week is shot with mandatory after work 'smoozing' and finding the rest of the parts for my car, hopefully I can make some progress by Thursday/Friday.

Cheers,
Dr. T

 

[Charles]

 

[gcrank1]

As a closely wound continuous coil they would work better on stretch than compression, the problem being coil bind (little compression length) and bottoming out. If the travel of the mechanism isnt much they might still work due to the highish rating. This is why I recommended valve springs. They arent chrome, but any engine rebuild shop or auto junk yard will have gobbs of them at different spring rates and dia.s to choose from.

 

[Dr. Tankenstein]

Being that the 'plan' for the springer is to go 'non-chrome', and the reasons gcrank1 mentioned, I'm gonna look into some valve springs.

My VW garage probably has some lying around......

Cheers,
Dr. T