Singlespeed & Fixed Gear - Ghost Cog?

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.




View Full Version : Ghost Cog?


NitroPye
03-08-08, 09:55 PM
I ran across this.. never heard anyone do this before. Kind of a cool idea:

http://www.dirtragmag.com/forums//attachment.php?attachmentid=17566&stc=1&d=1189540866


Ex Pres
03-08-08, 09:56 PM
Now that's HIP

ianjk
03-08-08, 09:57 PM
Used quite often on tallbikes, dangerous when combined with a fixed wheel... or so I hear.


wroomwroomoops
03-08-08, 10:13 PM
Worked fine for me. This is an old trick. And it's called ghost ring.

Soil_Sampler
03-08-08, 10:17 PM
yep! adjustable tensioner.

tjayk
03-08-08, 10:17 PM
wow, i have never seen this. so this is actually a reliable way to run ss on a bike with vertical dropouts?

pyroguy_3
03-08-08, 10:26 PM
Used quite often on tallbikes, dangerous when combined with a fixed wheel... or so I hear.

A sprung tensioner (such as a Single-ator) is a bad idea for fixed gears, braking would eliminate it from your bike. The ghost should work the same forward as it does backward. It's just a cog on an axle, mounted on the chainstay.

conor
03-08-08, 10:29 PM
it's not mounted to anything. at least i don't think it is.

MrCjolsen
03-08-08, 10:32 PM
Worked fine for me. This is an old trick. And it's called ghost ring.

With a name like wroomwroomoops, you can't be wrong.

I just went out in my garage to see if it works. It does. However, it takes only the slightest nudge to make it fall off. Did it ever fall off while riding. If so, what happened?

veganboyjosh
03-08-08, 10:54 PM
it's not mounted to anything. it just floats in there. if it falls out, then it needs to be bigger.

i've got one on a tallbike, cos the distance between the two frames/chainring and hub isn't adjustable. works like a dream. altho, it's hard to ride behind someone rocking one of these, cos it's like magic or something, and it's hard to not stare into the thing. it seems like it should fall out, or creep forward or backwards, but it works.

SuperVillain
03-09-08, 12:22 AM
Works for me. I've got a tallbike with 40x17 gear ratio, and a 40 ghost ring. Just barely fits in there without touching the cog or seat stay. Has never fallen out. I should mention that's it's a freewheel setup. I've ridden fixed setups with a ghost ring, and while safe (if done right), the play and the noise can be kind of annoying. Basically it's not the proper way to do things, but it will get you on the road.

EivlEvo
03-09-08, 12:31 AM
Wait... its seriously not mounted to anything? That seems baffling. I may have to self experiment. Wheres my chainsaw?

wroomwroomoops
03-09-08, 03:56 AM
With a name like wroomwroomoops, you can't be wrong.

I just went out in my garage to see if it works. It does. However, it takes only the slightest nudge to make it fall off. Did it ever fall off while riding. If so, what happened?

Get a larger one, or push the one you have closer to the rear hub a few links. You gotta jam it in real good, if you know what I mean.

relyt
03-09-08, 04:03 AM
If someone ever feels like being a dick and taking it out of the bike, you probably won't be able to ride until you find another one.

(And as someone who has had QR's flipped, and taillight brackets stolen, and brakes loosened, I know that some people really do feel like being dicks)

wroomwroomoops
03-09-08, 04:07 AM
By the way, experimenting with a ghostring on a tight chain is a good way to have a finger or two severed, because you have twice the "engagement points", or should I call them "traps". Use caution, keep your fingers out.

LóFarkas
03-09-08, 06:35 AM
I used one for a while, too (as an attempt to tighten the chain on my vertical drop frame, and for laughs)... Sadly, it kept falling out. You need lotsa space within the chainstays so that you can jam in a large enough cog... and you also need a large enough cog, about 24-26t, preferably 1/8 if you run a 1/8 chain.

You have to jam it in real hard, as close to the cog as possible.

BTW, if someone steals it (unlikely) or it falls out and you don't put it back (more likely) you're not stranded. You just risk dropping your chain.


Edit: damn you, guys, now I'm thinking of mounting one again... only now i run a bigger cog so I probably can't:( (ghost ring would hit the chainstay)

East Hill
03-09-08, 07:46 AM
it's not mounted to anything. it just floats in there. if it falls out, then it needs to be bigger.

i've got one on a tallbike, cos the distance between the two frames/chainring and hub isn't adjustable. works like a dream. altho, it's hard to ride behind someone rocking one of these, cos it's like magic or something, and it's hard to not stare into the thing. it seems like it should fall out, or creep forward or backwards, but it works.

It's a fairly common pratice with tallbikers. It does look cool, but definitely has drawbacks at times :p .

East Hill

VT tallbike
03-09-08, 09:25 PM
I've done this many times on SS tallbikes. Works quite well for this application. I've also done it on a fixed gear once just so I could ride home on a bike with vertical dropouts. It worked but I wouldn't recommend it as a permanent solution on a fixed gear, but SS works just fine.

EDIT... the weirdest looking thing ever is to use a biopace as a ghost ring FREAKY!!!

j0e_bik3
03-09-08, 09:31 PM
. altho, it's hard to ride behind someone rocking one of these, cos it's like magic or something, and it's hard to not stare into the thing. it seems like it should fall out, or creep forward or backwards, but it works.

I'd run into a parked car staring at that thing

fascinating

kjohnnytarr
03-09-08, 11:37 PM
Why not put that cog on a little axle, and mount the axle to a clamp on the chainstay? You wouldn't have to worry about it falling out, and you could adjust tension by sliding the clamp forwards and backwards.

EivlEvo
03-09-08, 11:51 PM
Why not put that cog on a little axle, and mount the axle to a clamp on the chainstay? You wouldn't have to worry about it falling out, and you could adjust tension by sliding the clamp forwards and backwards.

Cuz d00d... then it wouldn't be ghetto. I mean... why not just buy a chain tensioner? Or run gears? there... I said it.

ianjk
03-09-08, 11:56 PM
Why not put that cog on a little axle, and mount the axle to a clamp on the chainstay? You wouldn't have to worry about it falling out, and you could adjust tension by sliding the clamp forwards and backwards.

I wouldn't want anything clamped to any modern thin-tubed chainstay.... especially if it is getting torqued.

As you move forward, the pressure would torque down on the chainstay and as you brake, it would torque up. I could see this destroying a bike very quickly.

wroomwroomoops
03-10-08, 05:11 AM
Cuz d00d... then it wouldn't be ghetto. I mean... why not just buy a chain tensioner? Or run gears? there... I said it.

A chain tensioner wouldn't work with FG.

bward1028
03-10-08, 08:13 AM
Used quite often on tallbikes, dangerous when combined with a fixed wheel... or so I hear.

i managed to destroy 2 chainrings on my tallbike by putting them in as ghost rings.

kmart
03-10-08, 11:17 AM
Man I wish I had thought of this before selling that spare vertical dropout frame I had.

As for "jamming in the cog real tight" on vert dropout setups, why not remove the wheel, place the ghost cog in the chain and then squeeze the wheel back in the dropouts? (Or is that how ya'll do it now...)

thatcher
03-10-08, 11:18 AM
yep the pressure of the chains squeezing the chainrings would rob power transfer too. i learned this putting a chain guide on a minibike.