grooveboy

Hi guys my name is grooveboy.
When I was a kid we would build bikes from whatever we found in the hood and I remember building a 15 speed bike once back in the late seventies.

Now I just bought a used 21 speed mountain bike that I want to kind of customize and wanted to know is there such a bike or a series of parts to allow me to build one past 21 speeds and if there is, what is the highest speed bike, or I would guess the largest geared bike that I could build ?

Thanks

Aubergine 

Welcome, Grooveboy. The only way you will be able to get more speeds is to change your rear end. Bikes have been made with 8, 9, 10, and 11 gear cassettes for a few decades now. The issue for you is whether they will fit inside the bike's rear triangle. If you have access to a suitable measuring tool (micrometer is best), measure inside the rear wheel dropouts.

If the measurement is 130 mm or more, you can fit more than 7 gears. Then you'll need to determine if your rear wheel can handle a cassette with more than 7 speeds. If it can, THEN you will need to get a new rear derailleur and shifter that matches the number of gears you choose. If it cannot take more than 7 speeds, you'll need a new hub and spokes at the least, or a new wheel.

If your frame width is less than 130 mm (more or less . . . It is possible to wrestle a 130mm hub into a 128-129 mm space) you can take it to a shop to have it bent out to 130mm. And then go ahead with the other steps to get more speeds on your bike.

Philphine

test, just wrote a long answer but got logged off during it. aggravating.

DrIsotope

SRAM Dual Drive hub (3 speed internal) fitted with a 9-speed cassette and a front triple will give you 81 absurdly closely spaced gears.

ThermionicScott 

How many do you want? If you got a triple with a Mountain Tamer ring, and put an 11-speed cassette on a SRAM Dual Drive hub*, that would give 132 gears with probably tons of overlap, if my math is right.

* Not sure if this is possible, but they do make one that can take a 10-speed cassette.

dabac

...then add a Schlumpf geared crankset to that....

fietsbob

the hybridization of a cassette driver on the end of a 3 speed internal gear hub,IGH from Sturmey Archer will be 3x 8, or 9 speeds depending on your cassette choice

there is the potential to put another IGH, with a sprocket attached to the hub shell ** to have a chain down to the rear hub, with the hub up sat the top of the seatstay/seat tube joint, this requires a bit of frame builder type bodging..

then the chain from the crankset , which has 3 or maybe 4 chainrings, goes up to the cog on the 2nd IGH,
which turns the 2nd hub shell cog , that chain,

which in turn turns the gears in the back wheel..

** those hubs are made to go in adult trikes, to have 3 speeds ...

1957 I got a 3 cog cluster for my AW3 IGH, and a triple crank, so 3x3x3 or 3 cubed gives 27 'speeds'.







...

Philphine

I hate that this forum randomly logs me off. this is what I was thinking (I love a weird bike and was thinking of a crazy burrito/stretch cruiser with gears all over it), like a trike hub mid-drive, along with the sram dual-drive. you'd need an idler at the trike hub mounting point too, to allow a triple chainring up front.. also, it would take a bike that uses a one piece crank, and some creativity, but you could look for a dana 3 speed front crank set up. it only has one chain ring, but maybe you could work out how to make it a double or triple.

fietsbob

Look at John Howard and Fred Romplelburg's Motor paced speed record bikes for examples of how counter shafts
and 2 or 3 stage gear advantage, let them ride at over 150mph once the wind/air was pushed aside by a petrol fueled race car..

fietsbob

1 NuVinci CVR hub out of the wheel, driven by the cranks, Driving a 2nd NuVinci CVR in the rear wheel, could give you double infinity gears

7up

Now all you need is to figure out where to stick the FLUX capacitor.You can have some crazy off the wall TIME TRAVEL.Then you'd have to figure out how many LIFEPO4 cells to attain the maximum JIGGER WATTS....... but seriously i like your idea.Nothing like being different.Now you got me thinking.lol

fhalves

My bike have 28 speeds. I love her. =)

Philphine

I'm finally getting somewhere on a similar idea, but it wasn't a maximum gears idea (I may still try it though. it would make for a crazier burrito bike). I'm trying to get a better chain line. I need an idler to clear a suspension pivot on one of my stretch cruisers. I've been using a skate wheel with two grooves cut in it, but I'm trying to add a bracket for a three speed trike hub where the skate wheel was. I'm going with a 7sp freewheel on the back for a 21spd, but a sram dual drive and/or a triple front crankset, would kick that number up to crazier (though probably some duplicate) numbers.

VegasTriker

SRAM Dual-Drive is a great idea for achieving 3X8 or 3X9 in the rear but the company ceased producing internal hubs in February 2017 so what is available on the market is all there is and you will not be able to buy replacement hubs in the future. You can still do the same thing with Sturmey Archer hubs and they is no sign SA is abandoning the market as SRAM has. BTW SRAM sucks when it comes to being able to get replacement parts for the hubs they no longer make so that's something to consider too.

fietsbob

Yes apparently, Sun Race S-A is continuing to make a IGH & cassette driver combination Hub.

Sram is going for the High end road end MTB sector.

Philphine

still haven't set up a new photohosting site, but I got it done and it seems to work alright. only rode it a few miles and did the local cyclouvia, but now the weather has turned. if I come up with another trike hub I may go ahead and try the "gears all over it" idea. it'd probably be fun, especially if I could find a bunch of the old muscle bike stick shifts to control the various hubs/derailleurs.

MikeyMK

I had a Sturmey Archer CS-RK3 3-speed hub that took a cassette, i used an 8-speed with a triple up front, and that gave me 81 gears. But had i used an 11-speed cassette, i'd have had 99 gears.

The same bike is now 27-speed. My current daily is just 20 speeds, with 39/56 on the front and 11/36 on the rear, but the 39 is rarely used as it's electric.

wcap

double infinity is scientifically the most gears possible

fietsbob

CVR = continuously variable ratio, So gears beyond number.. Infinite, is not finite.. beyond a numbering scheme..

MikeyMK

The variable range is only within a margin, so it is finite. However, as you have two actual ratios, highest and lowest, you could say you have infinite adjustment within those parameters.

1500SLR

11x3 equals 33, but you would have to see whether your bike frame, rear wheel and bottom bracket can cope with an 11x3 setups. Even a 3x10 or 2x11 would give you more gear choices. However, a lot of those gears would be overlapping so it's not really always beneficial.

Philphine

i joined a facebook group (world of the custom bicycle) where someone has a 135sp (if i'm remembering right. somewhere in there). he admitted there's probaly some ratio duplication, but it's still a fun looking project. i'm still considering a 45-63 speed project.

it's just occurring to me if i put on a tension idler and used a triple chainring on the front of the bike i mentioned a few posts above i could get up to 63 (hmmm... using a sram dual drive would kick that up into triple digits...hmmm...), but i don't know if it would mess up it's being a favorite cruiser.

1500SLR

Honestly, its too many gears. Where riders are going to 1x11 and finding enough gears to suit their riding I don't know exactly what you're trying to achieve?

Jax Rhapsody

It just dawned on me; you used to go to the bike co-op a lot, didn't you? Falls City? I was there wendsday and one of the new(to me) guys mentioned that somebody bought that green chopper you made like two years ago and hadn't picked it up. It's JB. You're a true bike artist. My car broke down, so I'm back on a bike and trying to get this trailer built, hoping Nad will help me where it needs welding.

Kontact

More gear combinations allow you to have range and close ratios at the same time. With 1x11 you have to choose one or the other.