{"id":1137,"date":"2009-12-12T20:04:54","date_gmt":"2009-12-13T03:04:54","guid":{"rendered":"http:\/\/www.corbinstreehouse.com\/blog\/2009\/12\/building-a-tandem-unicycle\/"},"modified":"2018-10-28T17:49:29","modified_gmt":"2018-10-29T00:49:29","slug":"building-a-tandem-unicycle","status":"publish","type":"post","link":"https:\/\/www.corbinstreehouse.com\/blog\/2009\/12\/building-a-tandem-unicycle\/","title":{"rendered":"Building a Tandem Unicycle"},"content":{"rendered":"

\n

My last post introducing my Tandem Unicycle<\/a> originally started out with a step-by-step process of how I built it, but for some reason I lost the post. Here is how I made my tandem uni:<\/p>\n

\n\"IMG_6434.jpg\"<\/a><\/p>\n

This idea is not my original idea. A few years ago at a \u201cCalifornia Mountain Unicycle Weekend\u201d a guy named LobbyBobster on the unicycle forums brought one and I gave it a try with Beau Hoover. Here’s a picture of the creator and their tandem, which looks much nicer than mine!<\/p>\n

\"tandem<\/a><\/p>\n

So, from seeing this uni two years ago and based loosely on this picture I set about making my own for no cost. I already had two old bikes that I got for free, so I was set to begin.<\/p>\n

Materials:
\n* 2 Huffy Mountain Bikes<\/p>\n

* 2 Unicycle Seats<\/p>\n

Tools Used:
\n* Sawzall (with a bimetal blade)<\/p>\n

* 4.5\u201d angle grinder<\/p>\n

* MIG<\/span> welder<\/p>\n

* Half round file<\/p>\n

I took the wheels off of the old Huffy mountain bikes. One of the two rear wheels was going to become the main unicycle wheel, so I removed the rear cassette and saved the sprockets:<\/p>\n

\"IMG_6365.jpg\"<\/a><\/p>\n

The intent was to weld the two rear halves of the bikes together, utilizing the rear triangle that already exists. I used the sawzall to cut the front half of the bike off:<\/p>\n

(NOTE: in this picture I already had removed the seat post clamp for another project \u2014 you should leave it on if you are making your own tandem).
\n\"IMG_6367.jpg\"<\/a><\/p>\n

The rear triangle after I cut it free. Notice that the seat post tube is at an angle \u2014 I later cut it off and re-welded it vertical so it would be more \u201cunicycle like\u201d:<\/p>\n

\"IMG_6369.jpg\"<\/a><\/p>\n

And the rear triangle of the other huffy after I cut it free:<\/p>\n

\"IMG_6370.jpg\"<\/a><\/p>\n

I removed the main drive hub \u2014 one of the two has to be switched to the opposite side, and it worked well to remove both and re-grease everything after I welded it back together. Removing the hub was easy, even though I didn’t have the proper tool. I used a screw driver to get the reverse-threaded hub \u201cbolt\u201d out:<\/p>\n

\n\"IMG_6372.jpg\"<\/a><\/p>\n

\"IMG_6376.jpg\"<\/a><\/p>\n

The next thing done was to cut off the vertical tube and cleanup the two holes left in the hub housing:<\/p>\n

\"IMG_6381.jpg\"<\/a><\/p>\n

I then needed to weld the seat post tube vertical. I used a half-round file to cut a slight fish mouth out of the tube so it would fit nicely over the rounded hub housing. I then created a hokey setup to hold it vertical, testing the straightness with a square:<\/p>\n

\"IMG_6382.jpg\"<\/a><\/p>\n

I tacked it, and welded it on. Note that the big holes are left:<\/p>\n

\"IMG_6385.jpg\"<\/a><\/p>\n

I cut a piece out of one of the horizontal seat post tubes to use as a patch:<\/p>\n

\"IMG_6386.jpg\"<\/a><\/p>\n

I tacked it on:<\/p>\n

\"IMG_6393.jpg\"<\/a><\/p>\n

and then completed the weld. There is a patch on each side to cover up both holes. I then repeated the process for the other bike half. At this point I attached the two halves to the wheel to get a feel for it, and cut a top tube to size after making sure the bottom pieces were inline with each other:<\/p>\n

\"IMG_6395.jpg\"<\/a><\/p>\n

The next thing I needed to do was to weld the two halves together. I prepped the steel and cut off the angled slot on one side:<\/p>\n

\"IMG_6401.jpg\"<\/a><\/p>\n

I clamped them together, making sure the bottom pieces were in the same line with each other \u2014 that way, each seat post tube is parallel with the other.<\/p>\n

\"IMG_6407.jpg\"<\/a><\/p>\n

After they were MIG<\/span> welded together:<\/p>\n

\"IMG_6416.jpg\"<\/a><\/p>\n

At this point I decided to weld the freewheel on the rear hub’s cassette so it wouldn’t freewheel. Note that the hub spindle still turns free.<\/p>\n

\"IMG_6420.jpg\"<\/a><\/p>\n

The next part was to tack weld in the top tube in place, and cut some side tubes to fill in the frame:<\/p>\n

\"IMG_6423.jpg\"<\/a><\/p>\n

For the other side doesn’t look as good. It turns out the two bikes were different frame sizes, and I wanted the top tube to be horizontal, so I had to do some funkiness to get it that way:<\/p>\n

\"IMG_6425.jpg\"<\/a><\/p>\n

At this point I put the sprocket and hubs back together and stuck some unicycle seats in:<\/p>\n

\"IMG_6426.jpg\"<\/a><\/p>\n

The only thing left was to weld on two sprockets in the wheel’s hub. I took two sprockets of the same size (one from each cassette), with about the same number of teeth as the smaller hub sprocket (in order to get a 1-1 gear ratio). I made a spacer by grinding off some of the teeth on one of the sprockets and used some of the plastic spacers that were left.<\/p>\n

\"IMG_6428.jpg\"<\/a><\/p>\n

I then welded this to the hub (sorry, no picture).<\/p>\n

At this point, the whole thing was put together with two chains, and I temporarily used a large sprocket in between two of the chains to keep the chain a little tighter:<\/p>\n

\n\"IMG_6441.jpg\"<\/a><\/p>\n

Left todo is to create a chain tensioner, and to paint the thing.<\/p>\n

corbin<\/p>\n","protected":false},"excerpt":{"rendered":"

My last post introducing my Tandem Unicycle originally started out with a step-by-step process of how I built it, but for some reason I lost the post. Here is how I made my tandem uni:… [read more]<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[24,3],"tags":[122,121,18],"class_list":["post-1137","post","type-post","status-publish","format-standard","hentry","category-machining","category-unicycling","tag-tandem-unicycle","tag-uni","tag-unicycle"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/posts\/1137","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/comments?post=1137"}],"version-history":[{"count":1,"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/posts\/1137\/revisions"}],"predecessor-version":[{"id":5271,"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/posts\/1137\/revisions\/5271"}],"wp:attachment":[{"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/media?parent=1137"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/categories?post=1137"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/tags?post=1137"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}