Overdrives for Bents

[leog76]

Have seen overdrives for sale on E-Bay and wondering what an "overdrive" would do for my EZ-CX Sport. Where can I get information on these and does anyone have any experience with them. Thanks in advance Leo. :)

[bkaapcke]

It would make it possible to go faster. This, of course, will require more leg power. bk

[BlazingPedals]

You got a link?

You can get an underdrive and an overdrive by installing a SRAM 3x9 rear hub. Since you have to get a new rear wheel built around the hub, it's not a trivial expense. You can also get a Schlumpf Speed Drive, which gives you a 65% overdrive. Schlumpf also makes a Mountain Drive, which provides underdrive. Schlumpfs are geared bottom brackets, and are shifted via a button on the BB axle. (Schlumpfs are not cheap, either.)

I think Slyway has some sort of funky system too, but I don't know if it's for sale separately.

[leog76]

The link I was looking at on E-Bay is http://cgi.ebay.com/overdrive-recumbent-bike-and-trike-JOCEVELOS_W0QQitemZ160251339923QQihZ006QQcategoryZ106949QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[ejserv]

The overdrive you are refering to is a intermediate drive. I built one like it for my homebuilt trike but mine gives me both overdrive and underdrive gears. it effectively made a 10 speed drive into a 60 speed drive but I now have three shifters to deal with! not much of a problem as I seldom have to shift the front deraileur.
Ed Service

[charly17201]

I've seen these in some pics before, but thought they were primarily for racers. Do they have a somewhat 'legitimate' use for the casual (commuting/exercise/fun) rider?

[ejserv]

Well..... Yes... they do! Maybe your bike has an practical range of gears for you for the hills, type of riding you do. my trike needed lower gears to get up one hill we have here. there is a limit to how small a gear one can install on the crankset.I also felt I could go faster on the flats than the original gearing allowed. I could have bought a larger gear for the crank for that also. But now the deraileur on the rear needs to be longer to acommodate the increased range. It made more sense to install an intermediate drive!
Ed Service

[charly17201]

Well..... Yes... they do! Maybe your bike has an practical range of gears for you for the hills, type of riding you do. my trike needed lower gears to get up one hill we have here. there is a limit to how small a gear one can install on the crank set. I also felt I could go faster on the flats than the original gearing allowed. I could have bought a larger gear for the crank for that also. But now the deraileur on the rear needs to be longer to accommodate the increased range. It made more sense to install an intermediate drive!
Ed Service

Well, this does give me some food for thought...... I'm looking at doing an xtracycle build and this could really make that an even better utility bike. Not to mention what it might do for my 'bent. Come to think of it..... I could just about scrap the xtracycle idea in favor of a trailer with an intermediate/over/under drive.

Which is correct, or all they all correct terms? intermediate/over/under drive? Personal preferences like OSS/ASS?

[sch]

Rotator has used such a system for the past 18yrs on their bents, called a
mid-drive. Treks short lived bent also had the same set up. With a mid
drive you can dispense with the front der and just use a single chain
wheel in the 38-45t range. This also allows for a tighter rear cluster in
the 12-26 range. You have to have two Rear grip/twist grip shifters,
so the one on the L is used to control the mid drive derailler, and it could
be a 7 or 8spd as the cassette is 6spd. The R shifter is 9 spd for a
9spd rear cassette. On my Rotator this gives me a shift range of 7:1 for
a 'gear' from 22 to 144. Nice thing about the set up is that double shifts
are easy and only occasionally needed and you never run out of gears,
or almost never. I hardly use the smallest cog on the mid drive cassette
as it comes into play only above 30mph. I spin out at about 44mph.
I once saw a pix of a 10spd twist grip but didn't bookmark it.
Twist grips from Nashbar have been sold recently for as little as $10 for
a single grip or $30 for a set of 8 or 9spd twist grips with cables. (SRAM).

[ejserv]

all are correct. It is an intermediate drive because you have a chain from your crankgears to it and another from it to the rear wheel cluster. It is overdrive because you can drive the rear wheel faster than the intermediate shaft, and it can be a underdrive if you sellect right combination of gears on the intermediat shaft. I welded a spacer then a smaller gear than the largest on a 6 speed cassette onto the large side if the cassette. the chain to the rear wheel cassette goes on that gear effectively giving me underdrive when the front chain is on the largest gear on the intermediate cassette
Ed