Riff Ratt
- Thread starter Wildcat
- Start date
Help Support Rat Rod Bikes Bicycle Forum:
I may use all the scrap pieces of metal I have instead of having extensions for the forks and dropouts made up.
I dug out every piece of metal I have and laid it all out. I think I can use the brown metal straps as dropouts if I double them.
An hour's more work today before it got too hot and humid. I cut the rear fork and the struts for the front springer. I need to put something square on the fork tube, then have it welded. The struts get crimped and holes drilled, then sanded bare along with the rear fork.
It looks like the rear dropouts are going to be fabricated after all. Nothing I have looks worthy. I'll make up some templates and have them cut out in June.
It looks like the rear dropouts are going to be fabricated after all. Nothing I have looks worthy. I'll make up some templates and have them cut out in June.
I had forgotten my dropout extensions I made up recently. I think I have all I need. Those parts will work for the front springer and give me an extra two inches or so of height. That will allow a long bolt through both shocks for added strength. I just need to do some crimping and drilling holes. The ends of the original fork will get holes instead of open ends and the ends trimmed.
The round extensions I was going to use for the front can now be modified for the rear dropout extensions. I'm thinking of a half moon shape or a squared off look. I'll drill new mounting holes to get more rearward space. They will get bolted up in place then welded onto the fork.
The round extensions I was going to use for the front can now be modified for the rear dropout extensions. I'm thinking of a half moon shape or a squared off look. I'll drill new mounting holes to get more rearward space. They will get bolted up in place then welded onto the fork.
The mockup shows more height than I expected, but that's no problem, I'll go with the extra height.
Got some more done today. I chopped the ends off, drilled holes and bolted it together. It just needs some hardware, a 6" bolt to go through the bottoms of the shocks and some washers for the flanges. The knee action spring will probably do all the cushioning, I think the shocks are too stiff to really be used, unless I do some big jumps. 
The Renaissance Man
__CERTIFIED DIVER__ (Open Water & Open Dumpster)
Staff member
Moderator
Pro Member
I saw this in the highlights thread and wanted to pass on an observation that I made.
Your fork can work with dual action but at this point you have one too many pivot points. In the current configuration I believe that it will fold up when you put weight on it. If you eliminate the one pivot at the front of the drop out it should keep everything working more like you intended. You could either weld it in place or use two bolts (one above the other) and make it rigid.
A picture is worth a thousand words so this should show the problem that I see.
Even though this would keep it from folding up completely, you will now have an issue with the shocks hitting the fork arms. You could possibly remedy that with a couple of bump stops though. Interesting concept, I hope this helps!
BTW If you want to eliminate the dual action and just keep the shocks for looks, both pivots on the drop outs would need to be rigid.
Your fork can work with dual action but at this point you have one too many pivot points. In the current configuration I believe that it will fold up when you put weight on it. If you eliminate the one pivot at the front of the drop out it should keep everything working more like you intended. You could either weld it in place or use two bolts (one above the other) and make it rigid.
A picture is worth a thousand words so this should show the problem that I see.
Even though this would keep it from folding up completely, you will now have an issue with the shocks hitting the fork arms. You could possibly remedy that with a couple of bump stops though. Interesting concept, I hope this helps!
BTW If you want to eliminate the dual action and just keep the shocks for looks, both pivots on the drop outs would need to be rigid.
Or possibly a brace between the pivot point to the bottom of the shocks
I see what you're saying. Where the springs attach to the struts isn't a planned pivot point. That will be a solid attachment. I'm getting some hardware today and a 6 1/2" bolt will go through both sides with large washers and be tightened so it can't move. That will give some strength also to the struts.
The two pivots will be at the bottom. The 2 springs together are stout enough that they probably won't ever move, they are made for the rear of a moped that can carry two people. The original knee action will do all the suspension. I'll see when I'm riding how it goes over bigger obstacles.
Where the bolt goes through is the red, pivots are orange, the movement should be the blue arrow. Also, the tops of the springs will be bolted up solid to the top of the springer.
The two pivots will be at the bottom. The 2 springs together are stout enough that they probably won't ever move, they are made for the rear of a moped that can carry two people. The original knee action will do all the suspension. I'll see when I'm riding how it goes over bigger obstacles.
Where the bolt goes through is the red, pivots are orange, the movement should be the blue arrow. Also, the tops of the springs will be bolted up solid to the top of the springer.
The Renaissance Man
__CERTIFIED DIVER__ (Open Water & Open Dumpster)
Staff member
Moderator
Pro Member
Got it. That will work also. 
I suggested making the bottom rigid only because you could easily drill for two bolts. I'm still not sure how the single 6 1/2 bolt will make the two parts rigid but it sounds like you've got it worked out. The top of the shock will need to pivot slightly though if the shocks compress.
Looking forward to seeing it work!
I suggested making the bottom rigid only because you could easily drill for two bolts. I'm still not sure how the single 6 1/2 bolt will make the two parts rigid but it sounds like you've got it worked out. The top of the shock will need to pivot slightly though if the shocks compress.
Looking forward to seeing it work!
I've got a piece of tubing from another frame that will serve as a sleeve between the shocks as the bolt gets tightened up, making it solid. I expect to find problems I haven't thought of all along the way.
I got a lot of hardware today. No 6 1/2" bolts, but 6" might work. Wheels are finally trued up and got another set of BMX bars for a different bike. Now to put the springer together and mount the tires on the rims.
I knew it, a snag already. The shocks wouldn't tighten up even with the lock washers. The shock bushing center is the same width as the outside casing, so it won't tighten up unless I find a way to make it narrower or remove it altogether. Then it'll have a 1" hole for mounting. I'll have to give it some more thought. Maybe I could notch it somehow.
The Renaissance Man
__CERTIFIED DIVER__ (Open Water & Open Dumpster)
Staff member
Moderator
Pro Member
A simple solution would be to rotate the bottom mounts on the shocks so that they are perpendicular to the movement. You could add a cross plate to lock it from side to side also.
That looks like a good solution. I'll have to shorten the struts buy an inch or so to redo the mounting position on the bottom but that shouldn't be a problem. Thanks!
I tried it and it seems to work! I didn't want to shorten the struts so I used the original ones and trimmed them to fit. They are longer than the chrome ones so the extension lines up better along the main fork leg. Probably another inch in height. I had a scrap piece of metal that was the right length for a brace and it seems to be pretty solid.
I did some work on the rear swingarm also. There was 1/4" clearance on either side of the tire so I widened the fork the old fashioned way. I hammered the board in and tightened the bolt through the dropouts. Now I've got 1/2" clearance on either side of the tire. Next is the cutting and fitting of the extensions.
I did some work on the rear swingarm also. There was 1/4" clearance on either side of the tire so I widened the fork the old fashioned way. I hammered the board in and tightened the bolt through the dropouts. Now I've got 1/2" clearance on either side of the tire. Next is the cutting and fitting of the extensions.
More work done in one day!
I drilled some holes and bolted up the swing arm. I'm not adding a piece of square stock to the fork tube, it seems very solid like it is, no left or right slop at all.
This is using 5/16ths holes and bolts. The hardest part was wrenching all the lock nuts on. This will allow the arm to be adjusted left or right, mainly for chain clearance. I'll add a couple of washers next to the lockwashers where the movement will be.
I drilled some holes and bolted up the swing arm. I'm not adding a piece of square stock to the fork tube, it seems very solid like it is, no left or right slop at all.
This is using 5/16ths holes and bolts. The hardest part was wrenching all the lock nuts on. This will allow the arm to be adjusted left or right, mainly for chain clearance. I'll add a couple of washers next to the lockwashers where the movement will be.
A lot of engineering going on here, Wildcat! Just as an aside, those big whitewalls on those shiny rims that keep showing up in the background of your fork mods look really cool. Looking forward to your progress photos and posts!
RaT oN~!
RaT oN~!
I love how those forks are turning out. Glad to see you worked out the unplanned pivot points with the help of TRMs suggests.
