If you are building a frame from scratch, how hard is it to install derailleurs as opposed to Internal Gear Hubs?

It takes a few more minutes.

Depends on the frame

does it have horizontal dropouts, or an eccentric bottom bracket; so there's some way to adjust chain tension for a IGH hub?

A frame with vertical dropouts, will be a lot easier to setup for derailers vs a IGH hub.

Vertical dropouts?

If you need to ask....

Installing derailleurs (assuming front and rear) means installing a cassette wheel and multiple chainwheels, differing chain specs, and making decisions about what derailleurs will work with your configuration. all of which is of course far more complicated than an internally geared hub.

OK, if you don't know
then you probably shouldn't be building a bike up from scratch
you're going to end up 'painting yourself into a corner' with compatibility issues you didn't even know exist among all the different components..

On the other hand

every time I see a DIY singlespeed or fixie build up where the person chose the no-derailers route for supposed 'simplicity'
they inevitably have horrible chainline problems and give me a blank look when I explain to them that they need a different crankset/bottom bracket to fix it....
which then turns into a shocked/angry look when I explain how much the parts and labor will cost....

Welp, xenologer, now's a good time to educate me, since I've only bought a couple of parts (namely, a differential from Samagaga), but no derailleurs just yet. Below is the frame for my velomobile:



The two beams on the bottom are spaced 5" apart, and are what I'm going to attach the chainline to. Originally, I was going to use Internal Gear Hubs, but the frame weighs nearly 50 KG already, and some people suggested that derailleurs might stand up to the weight better.

Yea not a bike but a 4 wheel car like thing....

tried the public library yet?

I originally modelled it out using Merkur (a construction set like Erector), though some deviations from the model have taken place. And my public library has little in the way of information on actually building a 'cycle.

NObooks on bike repair ? none? i disbelieve. they borrow from other libraries ..ASk.

Or buy some .. Zinns bike maintenance/repair are good.. he has 2..

read on car design too .. steering is important.. ..2 wheels turn at a different radius,, (a round a common axis).. simple logic.

Well, I do live in a fairly small town. Our library isn't exactly the best.

That one I knew, as my Dad has worked on cars.

Considering the fact that I've made two screwups in measurements on this monstrosity, I might as well say, "Oh, what could POSSIBLY go wrong?"

Park Tool and Sheldon Brown web sites are great sources of (free) information about how most things work. I'll also give myself the liberty to recommend my site, BikeGremlin, with most standards and parts compatibilities (mix-maching) explained.

Derailleurs and gear hubs have their good and weak points each. In a car like setup, a gear hub would require some kind of chain tensioner, if rear to front chainring distance is fixed. If you find a way to move one of those relative to the other and lock it in place, then a chain tensioner is not necessary.

Dearailleur pros: no slipping under load, cassettes often provide a wider gearing range than IG hubs, a bit lower total weight (RD + cassette vs IG hub).
IG hub pros: allows shifting gears when stationary - good for a car like system. Works in deep freeze environment, doesn't freeze up from snow.

You have a very, very challenging road ahead, and that would be true even if you have a fair amount of experience. Even if all comes together fine, the total weight will run 80-90 KG unloaded. So the weight advantage of a derailleur system is a moot point. You also don't need more than one chainwheel, so no front derailleur, as your speed range will be small. Unless you are very strong even low gears will be a challenge, and forget about uphill. In addition, derailleurs shift poorly under load.

that is when you use the inter-library loan, system.. Libraries share their circulating collections.

You don't exactly have the right to act all smug about people making inapplicable comments
when you neglected to mention the Context in the first place of this not even being a Bicycle frame.

anyway, I'm out. Can't help you with this, I work on bikes, not pedalcars.

If you decide to go with derailers, this document might be helpful
it contains the Shimano specifications for derailer mounting
https://www.peterverdone.com/wiki/ima...%26_E-thru.pdf

you'll most likely want to only look at the 'standard' mounting on the first page, ignore the later sections on Saint/Zee DH stuff

The reason I was thinking derailleurs instead of IGHs is I was worried an IGH wouldn't stand up to the weight.

maybe not you need low gears to move that mass.

a typical trike drive the hub is not in any wheel, instead a counter-shaft between 2 separate chains..

They may not. Most IGH manufacturers publish a minimum recommended chainring/cog ratio to keep the developed torque within the hub's tolerance. The weight of your pedalcar may indeed exceed that limit.

One possibility is the NuVinci continuous variable transmission: NuVinciŽ Technology | Fallbrook Technologies Inc.

They are heavy and expensive but they make models rugged enough for your use.

You might find the Homebuilders forum on Bentrideronline helpful. I suspect there are more than a few folks there who have had some experience with velos.
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