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Thread started by WIFE BIKE at 01.23.09 - 12:54 pm
hey everyone! my buddy out here in boston is on his first tall bike build and is having some issues. since i know some of you are champion tall bikazz, i figured id ask for some advice. when i asked him what was wrong, he said this:
" its hard trying to get the top bike angled with the bottom so that it will steer. whenever you turn the bars the back end pivots. so once the back end is welded too its not gonna turn.... or tear itself apart"
that makes absolutely no sense to me, but then again, its me.
here is his email if you feel like being awesome.
plytheman@gmail.com
his name is patrick.
p.s hi guys!!! i miss you!!!
You got to put a pipe thru the two steer tubes to make sure the front is aligned before you do any other welding, this is critical. Also a smaller wheel in fornt like a 26 in back and 20 in front helps the handling a lot, but that's an LA thing
When we build these beasts on the westside not only do we have a long pipe through both head tubes to make sure that they're lined up, we also clamp some boards against the frames to make sure they're straight. The last thing you want is to have a bike where the frames aren't lined up. Once you get the head tubes lined up it's just a matter of grinding down the seat tube area on the bottom frame until they fit together.
And be careful not to get any slag in the Bottom Bracket, that majorly sucks when you try to put the thing back together.
If the two head tubes aren't aligned perfectly you'll have bad issues with the steering. Putting a pipe through both head tubes and then welding the seat tubes where ever they end up is the best way to ensure the head tubes are lined up.
Its best if the pipe you use to align the head tubes is fairly close to the inside diameter of the head tubes other-wise you might not get it close enough for the steer tube to move without rubbing the unaligned edges of the head tubes.
If that happens you'll have to grind on the steer tube wherever it rubs until you can make it spin freely.
Also if you are building a singlespeed or fixie tallbike without a derailleur make sure that the dropouts on the bottom bike are still at an angle that will allow you to adjust the chain tension from the top bikes crankset.
Shannon gave me the link over here so I just registered to thank you all for the tips. For some reaon we thought it would be easier to run the steer tube from the hacked up stem on the bottom bike to the hacked up fork up top. Makes a lot more sense (and in retrospect is probably a lot easier) to just do it like you guys were saying. Hopefully the conduit we have will fit through the head tube...
I'll probably try to rig it up to shift but I'll cross that bridge when I get to it. Worst case (assuming I cant get the derailluer set up) I'll rig an extra cog up somewhere along the chainline to hold tension. Thanks again!
Use conduit as a guide thru the steer tubes but u dont have to use it as a final steerer, In fact I find that method of steering is weaker. Use the conduit as a guide, but fork to fork (not fork to stem that shit waaay limp) is not bad at all. If u can see on my profile pic my connection is fork to fork connected with Re-bar. I crashed into a civic one time (totally my fault) and it still steers straight enuf for no handed riding. The civic didnt start and had to be towed away.
chainrings can help tension, and BTW a coaster brake on a Tall Bike is the shit... Also BMX bars and stems... basically everything Im tellin you is what I ride and win jousts and come in second to Paul at battle royales on... do what you want
oh and Paul if yer reading this I'm gonna rip your arms out and beat you with them next Choppercabras <3
The first thing we tried was just fork > handlebars and then we tack welded the back and tried steering and could turn the bars like... 5 degrees in either direction, if even. Thats a pretty sweet way to skip the bars in the steering. We've hacked the top bike's fork way too much to do that, but we might be able to find some scrap metal somewhere and rig something up like that.
Yeah home made steer tubes welded onto the fork tend to break a lot. The steer tube has to carry all of the weight transferred to the front wheel. Mine have all been the same size tubing butted together and one welded and one brazed. They both broke after a few hundred miles.
RichToTheIE just told me a new method for welding them with a thin tube that fits into the tube on the fork and then gets drilled and welded through the hole....that should be stronger.... but what Alex says about leaving the forks on the top bike and welding them to the forks on the bottom bike is probably the strongest way I've seen it done.
Dan built a fully geared tall-bike that was auctioned off for a burning man fundraiser. It had a derailleur welded onto the seat tube to set the tension between the top-bike crankset and the bottom-bike crankset.
The angle of the head tubes must be the same or you'll get the steering problem. One way to deal with it is to spin the bars all the way around and the frames will flex to a point to where it will steer. Keep in mind that it only needs to turn about 1/3 of it's whole rotation to work.
Alex? Are you serious, have you beat me yet? I've only lost one tall bike joust or battle royale and I quickly redeemed myself on that one loss. I've even had the cartilege torn off my ribcage after being struck by a lance (which broke on me) and still took the win. That's 50+ wins to your none.
What I have planned in spring, we'll see it will be a little different and much harder.
Dan built a fully geared tall-bike that was auctioned off for a burning man fundraiser. It had a derailleur welded onto the seat tube to set the tension between the top-bike crankset and the bottom-bike crankset.
Once again WifeBike got me all excited and let me down. jk. I thought this thread was about a tallbike only ride. The most we’ve gotten together is three. We can beat that! Maybe fill in the even months that Los Angelopes is dropping (?).
wait alec, didn't we have 5 or so on the ALC welcome ride? I know it was you, me, E-Rock, Spook and maybe stilline or tall cans.
Here is the method i started using. First thing i do is line the two frames up with the cups in the head tubes. I use a piece of pipe that i ground down to make a tight fit. This keeps my head tubes lined up. After that I use a level and clamp that to the bottom brackets on the drive side of the bike. This is to give you a proper chainline if you are running the chain from the top frame to the rear wheel. If you want to make it fully geared most likely you will have to do it on the non-drive side. I'll fill you in on how i did it if you need me too.
For the steer tube, the first thing i do is use a pipe cutter and cut the threads off the steer tube on the fork i'm using. This should give you a nice clean and straight cut. The next thing i do, is get a piece of 1" outside diameter tubing (usually scavenged from another bike), and i allign that with the steer tube from the fork i'm using (make sure to use the pipe cutter to cut the ends to give you clean and straight cuts). Cut the extension so that when it is coming out of the top of the top head tube, you have room to put threads on it. Next, find a piece of tubing that will fit nicely inside your existing steer tube and your steer tube extension. You want this to be a tight fit and should be about 6 inches. Slide that in and put your steer tubes together. If you do this right and lay it on a flat surface you should get a perfectly straight steertube. Once you have welded your steer tube, use a drill press and put a couple of holes all the way through your steer tube and the inserted pipe on each side of the weld. Home depot and metal supply shops sell thin steel rod. Get a piece of that and put it through the holes you just drilled. Make the rods just slightly shorter than the diameter of the steer tube, and then you can weld over the holes to secure the rod well. Once this is done, grind your steer tube to make sure it fits through the cups on the head tubes. Last thing to do is thread the top of your new steer tube. If you don't have access to a pipe threader, you can cut the original steer tube in half and use the old threads. This just means you will have two welds on your steer tube instead of one.
The last tall bike we built, we also removed the middle cups, and welded a tube that matched the head tube diameters. Then i filed it down smooth so it looked like i just had a really long head tube.