Posted in the help section because I want your ideas/help.
Going to build a tallbike. It will be fixed. Here’s the plan(s)
any ideas?
Basket idea from tomhall, saddlebag from a.davis12
About chain/steerer issues?
i think you may have a fair bit of trouble keeping the chain on with that set up.
just a thought here, but it might work out a bit better with two chains. running two road chainrings up top and bottom so you don’t need tandem cranks
you are right, yes, the adjustment. Especially because I’ll be using 2 old roadies.
Tom might be right,
is that what you mean tom?
Also, LukeR, even in theory, make sure your saddle is level 
ahaha that is the first thing i thought when i looked at that image
Why not just change the angle of the dropouts top be in line with the crankset ?
Steerer tube and head tube can be some thick walled pipe/4130 if you want to be fancy.
how the hell do you get on that thing
i think i direct chainline with the rear wheel would be far better. Im guessing you’re going to have some epic problems with your chain dropping with the triangle drivetrain approach, and I don’t really see any benefit to it…
1 minute of googling can give some design inspirations:
i dunno,
Wheel and Sprocket’s ebay store had some tandem cranks for around 50 posted to Aus a few weeks back, might be worth checking if they are still there.
As an aside - this is awesome. I normally hate seeing tall bikes with the lower bottom bracket unused.
how would yo reach the bottom bottle cage?
I come here to publicly lambast you for having more silly tall bike dreams.
But then i saw it and i thought it was brilliant.
Headtube was gonna be the top tube from my bent first roadie. Top tube and seat tube are still in good nick. Steerer tube, I figured if I just found something 1" wide and welded it in, it could be all good.
Also, bottom bottle cage there for storage of wd40, or spray paint, or a spare bottle.
Hellocoulson, there’s a whole lot for me to learn about mounting, but I’ll figure it out. Usually guys have pegs to climb up.
Prawza, that green one is a geekhouse tallbike, I’m sure. Custom, I like it.
The cycling weapon of mass destruction one is what gaveme the idea to reuse the chainstays on the back.
lots more to think about, sounds like the triangle chain idea is out.
personally I’d get used to riding a freewheel tallbike before you try fixed. as they say of many things, its not the going that hurts, its the starting/stopping.
you might also want to consider a lower peg/stand to help you get on as the ‘normal’ way to mount the bike is using the lower pedal to climb on and this wont work/be easy if its rotating.
i find tallbikes are fun for about 10mins then the novelty wears off, but i also know a couple of guys that have built some amazing ones (tallbike tourer? TT/pursuit tallbike?) and have done some crazy stuff on them like hillclimb races.
Freewheeling tallbike eh?
Might try and hook a deralieur up as well then.
And it’s those 10 mins I’m looking for dude, if I still find it fun maybe I’ll build a really good one.
I have considered a lower peg, I figured I’d use some old cut up chainstays.
Do you really want a fixed tall bike? You can solve your chain tension problems by making the bike a single speed and using a chain tensioner. However, I can see that you will need it to be FG if you want to be able to ride backwards.
I suggest you set up a drive train that:
(a) uses both bottom brackets - the top bottom bracket (TBB) and the bottom bottom bracket (BBB);
(b) uses two chains - one from the TBB to the BBB, and the other from the BBB to the cog;
(c) the BBB will have old/cheap chain wheels on both the left hand side and the right hand side of the bottom bracket (you can hack the crank arms off those chain wheels if you want a cleaner look);
(d) the TBB will be set up with a left hand side drive train and will drive the left hand side chain wheel on the BBB;
(e) the chain between the BBB and the cog will run on the right hand side and will be tensioned the same way it would be on a conventional bike;
(f) tensioning the chain between the TBB and the BBB will still present a challenge - but it will be made easier because it is a shorter chain run; and
(g) that tensioning could be achieved by:
(i) looking for a ‘magic gear ratio’ (if that works out to be an unfortunate ratio, then you can correct that ration by altering the gearing on the bottom drive chain - between the BBB and the cog);
(ii) using a half link;
(iii) using small chain rings on the drive train between the TBB and the BBB and using a really large ‘ghost’ chain ring between them (which could look pretty cool); or by
(iv) using an eccentric bottom bracket if you have lots of $$$.
I’m really looking forward to seeing the end result - regardless of how its built. I’m particularly curious about how you’re going to connect the steerer tube on the forks (at the bottom head tube) to the stem (above the top head tube). hwilliams has suggested “thick walled pipe/4130”. But how are you going to connect that to the steerer tube and stem?
Cheers
PS - For an example of a ghost chain ring see Canfield | Mountain Bike Reviews Forum . According to Sheldon a “ghost chain ring” is “a chain ring somewhat larger than the synch chain wheels stuck somewhere in the middle of the synch chain, with its top and bottom teeth engaging the synch chain. As the upper part of the synch chain moves forward, the lower part moves backward, so the ghost chain ring revolves while holding its position, even though it is not attached to any part of the frame. It is quite an eye-catching effect” (see Home-Built Tandem Bicycles).
i wasnt having a dig… promise!
i’ve ridden a variety of choppers (thanks to some ever-present freak bikers in vancouver). some dont even make the 1min mark before you get off and hand it back. others are hilarious fun… (swingbikes in particular and this)
i say go for it… you’ll learn a bunch about drivetrain set up and bike design along the way…
NOBR AKES or nothing.
The obvious way would be to make the tube a slip fit inside (or outside) the existing steerer tube, and wick some silver or brass rod in there.
or you could have a stem style clamp that grips the outside of a ahead stem.
or a fancy cam system that is actuated from the top, like a quill stem.
It all depends on the technology/skills available.
I personally would weld/braze a tube in there since it is probably only going to be used a few times, and overhauling the headset(s) etc would not be a huge priority. Saying that there is something to be said about doing it once and doing it right.
Hugh
nothing will top that build.
Here is an interesting idea - Build Your Own Tall Bike Without Welding .
I know it’s as ugly as hell – but I quite like the concept of using a single bike frame, flipped over so that:
(a) there is only one bottom bracket on the bike (which should keep drozzy happy); and
(b) the horizontal dropouts or track ends are in the same geometric plane as the bottom bracket - which should make chain tensioning very straightforward.
With a bit of thought, and some welding skills, it should be possible to turn that basic concept into something attractive.
The best FG tall bike I’ve ever seen was one of the winners of the Fixed Gear Gallery 2008 Open Design competition. Unfortunately, the FGG website no longer seems to have the results of that competition (see Fixed Gear Gallery Contests ). It was a cruiser-type tallbike in which the curves of the original cruiser bike frame were continued down to the wheelset, far below the bottom bracket.