[Closed] If you could design your own bike what would it be?

lugged steel bike with an alfine 8 speed hub and drop handlebars

I'm building up one at the moment, with carbon forks and a-headset though rather than its original reynolds ones.

My idea of the future;

[b]Hardtail[/b]
Gearbox mounted half way up the seattube
Belt drive from Crank to gearbox then Gbox to hub

[b]FS[/b]
Same thing but the G-box mounted concentric with the pivot axle of a single pivot rear sus

Must have a burning skull on it somewhere

WHY THE HELL, has no one thought to put an alfine hub, where the bottom bracket is?

Fixed rear wheel*, no working parts on it, so ALL the mechanisms, freewheel, gears and all that guff, are in an oversized BB housing,which holds what it basicly an Alfine hub with threads on the outside.

moves the weight to the middle bottom of the bike, and keeps it out of the grime more.

before anyone says "basicly a gearbox bike"
yes basicly a gear box bike, but no fancy new tech, the tech exists already, it just needs tweaking to fit in a different space.

genuinly tempted to buy an alfine hub, and take it apart, to see if its viable to convert them....

(* chain still turns when you coast, like on some bmxs and trials bikes)

Olly, I can't see any easy way to hook up the cranks and frame without re-designing the afline hub shell..... mmmm has got me thinking though.

PTC have a hard on for splashing the various screen grabs of Santa cruz frames in their Pro/e promotional gubbins, I remember going to a seminar a few years back and they used what looked like a model of a blur to demonstrate some feature or another in pro/mechanica I think…

Never seem to have company logos shown though, you realise your just doing their job for them; supply a decent model and it’ll wind up being used in tutorial excercises, supply a pretty model and their marketing gibbons will work it in to their materials, neither you or your employer will receive any credit or logo placement, just a waste of your time, Just model them a penny-farthing… Lunch time piss about job.

WHY THE HELL, has no one thought to put an alfine hub, where the bottom bracket is?
Fixed rear wheel*, no working parts on it, so ALL the mechanisms, freewheel, gears and all that guff, are in an oversized BB housing,which holds what it basicly an Alfine hub with threads on the outside.
moves the weight to the middle bottom of the bike, and keeps it out of the grime more.
before anyone says "basicly a gearbox bike"
yes basicly a gear box bike, but no fancy new tech, the tech exists already, it just needs tweaking to fit in a different space.
genuinly tempted to buy an alfine hub, and take it apart, to see if its viable to convert them....
(* chain still turns when you coast, like on some bmxs and trials bikes)

I refer you to the Millyard bike and the Rohloff based gearbox that nicholai produce, WHY THE HELL have you not heard of these?

Downhill fixie recumbent 29er....

I could tell you but it would cost.. 🙂

Searching on Millyard got me a picture of a monoblade rear swing arm.... Mmm now lefty front, lefty rear GBOX arrangement, 29er with an alfine rear hub and hubless wheels. Shoot me now.

i think it would require the shell redesigning to be a thread, and the axel redesigning to be a BB axel, AND then the gearing flipped around so it gears the other way around (as youve then swapped the drive and the crank axels)

ive seen the millyard bike, but its a bit of a fatty.
i dont see why there would be any need for the oversized BB to be any bigger than an Alfine hub.

genuinly tempted to buy an alfine hub, and take it apart, to see if its viable to convert them

which is where I ended up with my idea, because some custom re-threading I rekon you could build it into a bike today. In a drunken moment I actually considered ordering up an inbred frame and seeing if I could do it myself. Then I sobered up and realised that I can't weld.

putting an alfine in the BB space is essentially an extension of the Schlumpf/Hammerschmidt idea and while I can see the advantage of a lower CofG I rekon you'd have less problems putting it higher up, especially when SFB decided to go riding through rivers with it

WHY THE HELL, has no one thought to put an alfine hub, where the bottom bracket is?

Don't know about Alfine, but Rohloff have got a minimum gear ratio to protect the hub from excessive torque.
If you put the cranks directly on the gearbox, then that is effectively a 1:1 drive ratio, far more torque than a Rohloff is designed for.
From what I remember of looking at the Nicolai frame mounted Rohloff, the cranks are below the gearbox and, presumably, there is some sort of gearing between the two.

It's a tad more complex that pulling a hub apart and jamming the planetary gearbox components into a BB shell though isn’t it…

Firstly the axle is massively undersized for running cranks, thus you’d need to re-scale the whole thing around a larger axle, so you are basically having to design a whole new gearbox, then you’d need to run the whole lot inside yet another set of bearings (as it’s now mounted static in the BB shell, not in the centre of a wheel) your BB shell would have a diameter somewhere in the region of 8” the whole bike would weigh more than a normal Alfine setup and you’d have achieved no functional improvement (other than the somewhat marginal benefits of moving some weight between the cranks) , mounting a re-housed hub just above the BB and having a 2 stage drivetrain is about the most efficient way of getting what you’re after, or just putting the gearbox in the rear hub, which the alfine already does as standard…