View Full Version : swingarm pivot

05-20-2012, 01:18 PM
Forgive me if I do this wrong - this is the first time I've sent a message since the changes were made. I have a little problem with the tadpole recumbent I'm building concerning the swingarm pivot. I have two bikes that have the rear triangle that I can use, but both bikes have aluminum front frames and I can't use the pivot since I won't be able to weld it. I thought about just going to a metal supply place to have them match me up with a piece of tubing like the aluminum one, and then source a pivot bushing. Problem is, I can't even find someone that sells the bushings. Should I get a machine shop to just machine the bushing and pivot, or is it going to be cheaper to just find another bike with a steel frame? Sorry if this is "an old question". If someone can direct me to the right answers I'd be most thankful!

Radical Brad
05-20-2012, 06:17 PM
Could you just push out the bushing and then have the shop make you the tube?


05-21-2012, 12:11 PM
I tried to tap out the bushing from the inside with a brass drift, and it seems the bushing is made of some kind of pot metal, as it started to break. They are in so tight I know I won't be able to get them out "intact".

05-21-2012, 12:48 PM
There are two ways I would try. I have never saw one so you will have to pick best way. first way is to use a zip disc to split the sleeve the bushings are in. this will release pressure on bushing so you can tap them out. It may help to drive a screwdriver in the cut between the bushings. that may let the bushings fall out. the zip disk WILL damage the bushings . If you are careful the damage will not be severe. I don't think it will hurt anything. Second way is to cut sleeve off frame . cut sleeve in two peaces so the the bushings are in separate sleeves. Press out. May have to split sleeve to .

05-21-2012, 02:06 PM
If there is no plastic with bushing heat sleeve and quickly tap bushing out. aluminum heats easy and moves a lot. Another way: It may be possible to put sleeve in lathe and turn sleeve off bushing. I think one method will work. Remember I have never seen one apart so I may be giving BAD advice. I may be trying to take bushing apart later so let me know what works for you.

05-21-2012, 06:40 PM
While trying to gently drive a sharpened screwdriver between the outer rim of the bushing and the sleeve to see if it would loosen up, I accidentally broke a small part off the outside rim. This may be a good thing since I can now see the thickness of the pivot sleeve to find a similar piece of steel pipe or have one made. The bushing can still be used (if I can get the freakin' things out in one piece!). At this point I think I'll pay a visit to a couple places that might be able to match a similar piece of pipe and/or make the sleeve and bushing, and if financially feasible I'll have it done. If not I'll try the advice you guys gave to try to separate the sleeve from the bushings. Thanks a bunch - I'll post the outcome later!

05-21-2012, 07:34 PM
Use a long bolt threaded in it and hammer it out then use a brass punch after you remove collar and drive it all arart with that

06-21-2012, 08:33 PM
I'm back in the saddle after taking time off to nurse a fractured hip (long story), so I'll try to catch up on the "swingarm pivot" problem I've been trying to solve. I've added photos so maybe it will be easier to see where I'm going with this, and get some feedback from you non-rookie builders. After trying to get the pot-metal-like bushings out, I decided to try to set up a swingarm without the bushings, using only a thick piece of pipe that had a 1.25" o.d., and a .75" i.d., with a .125", (1/8") wall thickness. The big problem is that the i.d. needed to be reamed out to .782" for the pivot insert and bolts to fit in, which is what the i.d. is for the bushings. This would eliminate the need for a bushing, and although the o.d. of the pipe to weld it to the 1 1/2" square tubing frame, I decided the 1 1/4" o.d. would work just as well. The problems I ran into were, 1) it took much longer than I thought it would to ream out the inside of the 2" length of pipe, 2) the cost for the pipe was $10.50 for a 12" section, which should have been enough to make at least 5, 2" pieces, but the 3/4" cutting tool I bought to ream it out was $20.00 (including shipping), which made it too expensive unless I was able to get several pivots made for future bikes. So, the problems were that the cost and time both were prohibitive to make a swingarm pivot this way. The only bright spot is that I got two machine shops (out of 4), to call back with a bid to machine out the whole 12" length of pipe, one was $155, the other $230. I therefore put in the extra time grinding and reaming it out to just get a 2" piece done to use on the recumbent I am now building. I'll have to figure out something else for future bikes if I can't source a metal swingarm pivot to use, but it has become my "mission" to try to find some alternative to use in place of the aluminum pivots for my future builds. Hope I haven't bored you all with this. I'm still open to suggestions, as I really want to find a good way to make something to replace the aluminum swingarm pivot. The photos I'm posting hopefully show the 1)broken bushing I couldn't get out, 2) the pipe and tool I used to ream out the pipe - the one I bought and one I made from conduit to wrap with sandpaper, 3) the finished piece with swingarm insert and bolts.4539454045414542

06-21-2012, 10:16 PM
What i did was find a piece of pipe that almost fit the bushings. (at local recycle center) i honed it out a little with a wheel cylinder hone. That took too long so i jury rigged a set up for my drill press using the pieces the slide into the bushings and a bolt thru it with the bushing mounted to that and spun it on the drill press. i just held a belt sander to it til I had a proper fit. The hardest part of it was finding the pipe. I have to get a lath cheap some how, maybe i can barter or something. there's always a way it you have a little tenacity

The Cat
06-22-2012, 06:02 AM
An idea if I remember correctly was a closed tube length and loose size of bearing center drilled for a bolt. A thick washer or drilled round stock size of bearing.
A bolt of length twice to three times length of closed tube swing-arm pivot bearing is housed in and washer or drilled round stock. Place closed tube on one side of swing-arm pivot housing with bolt through to washer or round stock add nut and tighten nut. Turning nut forces bearing into closed tube.

With Regards

Thomas (The Cat)