cogs in back, single gear up front???

Wheels4

I'm not sure if anyone does this.... but, I've got a frame and fork i'm building up as my commuter/single track bike... and i was thinking that since i don't use the small ring and hardly use the big ring(got the road bike for fast stuff).. might be easier for me to make this a 9 speed bike. besides cranks with one chainring... is there anything else that I would need to purchase? assuming this is a good idea(which seems to be, for me)

thanks for any help given...

:D

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shants

depending on how you set it up (chainline of front ring relative to rear cassette), you might not be able to reliably use some of the gears with a 9 speed. i'm not particularly well-versed with respect to chainline tolerances on geared setups, but i know that you can only have it so far off. i suspect that, with a nine speed, if you can get the single chainring straight on with the fifth gear, you will probably be okay. just something to take into account.

Momentum

You relaise that this is the singlespeed and fixed gear (ie bikes with one gear) forum, don't you? You may have better luck in the commuting forum.

kbabin

The setup you are looking for is used by alot cyclocross racers. Post there for help...

Kevin

Wheels4

You relaise that this is the singlespeed and fixed gear (ie bikes with one gear) forum, don't you? You may have better luck in the commuting forum.

yes, I understand what forum this is... I was just asking.

thanks for the input all... I'll take it over to the commuting forum.

eyefloater

It should work. Your chainline might run into trouble if you were thinking of using the largest or smallest ring, but in your case it should work fine.

mattface

Back in my day we used to call that a 5-speed. I think you'd be better off using in internally geared hub like a Shimano Nexus INter-8 or SRAM S7

mattface

You relaise that this is the singlespeed and fixed gear (ie bikes with one gear) forum, don't you? You may have better luck in the commuting forum.

Oh like we are all bastions of on-topicness here. A few of us know something about gears, and are more than willing to help someone with an unconventional setup.

shants

end of thread.

Lunigma

sheldon brown has a similar setup, i forgot which bike he uses it on. one problem you might run into is that the chain might fall off the front. you should use a single speed chainring with high teeth so that it wont shift off. you could also use chain stoppers which prevent the chain from falling over.

vobopl

or a front derailleur (no lever necessary) to act as chain guide.

Wheels4

thanks for the suggestions guys... I've already done a search and found some issues to look for: like the 3rd eye chain thing, fr derailler fixed in one position. I was just wondering about chainline and spacing issues with a 9sp cassette... and anything else i was not aware of.

My next question was going to be how to set up as a single speed with the hub I already have instead of buying a fixed gear or s/s hub. but... I think i'll think about it alittle more.

thanks again everyone....

jamey

isn't this a common set-up for trials riders? keep in mind i said TRIALS not time trials..i could see everything getting out of control if i didn't make that clear.

Alexi

I rock that some times on cross bikes, just go to cyclocrossworld.com and pick up a dog tooth or a third eye

Momentum

Wasn't trying to be rude - just checking that you knew.

If you're commuting with it (ie not doing trials) then you may find that a non-ramped, high tooth singlespeed/track ring on the front keeps the chain in place without needing a derailleur or other funky devices.

lala

Moved to cyclocross, since OP began a thread in commuting.

Spudmeister

i was thinking that since i don't use the small ring and hardly use the big ring(got the road bike for fast stuff).. might be easier for me to make this a 9 speed bike. besides cranks with one chainring... is there anything else that I would need to purchase?

I did this with a mtb bike a few years back - worked fine.

doco

hey wheels, I am going to do the same thing. I bought a cheapo mtb bike at a garage sale for 15.00. I am going to convert it to a single speed beater. there are several places that have a tension device and spacers for the back. I am going to just take off the fd and put on a jumpstop to stop the chain coming off, then I am going to put this kit on from nashbar and try it out. i'll see hopw it works and go from there. here's a link to nashbar kit, 29.00 is cheap enough....also surly has some options too but more money...

http://www.nashbar.com/profile.cfm?category=87&subcategory=1109&brand=&sku=14063&storetype=&estoreid=&pagename=

doco

oh if you decide on the nashbar set, get the 10% off coupon and use that too...whole thing will set you back 26.00

Wheels4

oh if you decide on the nashbar set, get the 10% off coupon and use that too...whole thing will set you back 26.00

thanks doco.... appreciate it. and thanks to everyone else too. I might try the single speed option... not sure if my legs can handle the hills with just one speed though. :D

xlntRider79

or a front derailleur (no lever necessary) to act as chain guide.

That's how I roll. (40 front, 11-32 rear) If your middle ring position lines up with the middle of the cassette well, then you should be able to use all 9 gears with no problem.

jeff williams

There's a few threads on this in the mtb forum. 1 current and many to find using the search function.
Mtb cranks you just run the ring on the middle mount of the triple, chainline should be straight to the 5th cog. A single on a double would have an incorrect chainline -use a track or bmx single crank\spyder I guess?
Mines 38 to 11-30 not dedicated offroad, I do trials type climbing.
Max around 21.8? mph @ 80rpm flatland (26 inch wheel.) do it on 7-8 clusters (I need a strong chain for climbing).
Less IS more...fun.

And lighter.
G-luck

Wheels4

xlntrider.... how is that ratio working for ya? you climb alot with it? I have some pretty hard climbs on my commute.... and I was thinking about going with a 40 or something close. My cassette is 11-34 so that helps alittle bit.

xlntRider79

Honestly, the MTB cassette is overkill for road riding, I problably use only the 6 smallest cogs on the road, even on steep hills. Of couse I'm more of a "masher" than a "spinner"

For CX the combination is usually pretty good. I say usually, because last Sunday, the mud was so thick that I could hardly turn the cranks on the flats and even had to pedal to carry any speed on the downhill sections. I was really wishing I had brought my MTB to the race that day.

jeff williams

I'm 38 to 11-30. Runs great on anything. 26 inch wheels.

Wheels4

LBS says I should run 32 to 11-34. I think I can handle the 38 though. we'll see.

jeff williams

LBS says I should run 32 to 11-34. I think I can handle the 38 though. we'll see.

They suggest that for what? climbing?
http://www.sheldonbrown.com/gears/
You would be under 20mph spinning 80rpm flatland 32-11.
No fun. 32,34 I see on offroad bikes.
You've got a 34T cog! No need to drop the front T count too low unless you're touring with weight.
Be nice if you could pal up and borrow rings to test, 32,34,36,38.
I did my 38 on the leg strength I have climbing, and I was spinning out 36-11 flatland.
IMO, and as I stated, my experience is with 26 inch wheels, road/offroad/climbing.

Wheels4

They suggest that for what? climbing?
http://www.sheldonbrown.com/gears/
You would be under 20mph spinning 80rpm flatland 32-11.
No fun. 32,34 I see on offroad bikes.
You've got a 34T cog! No need to drop the front T count too low unless you're touring with weight.
Be nice if you could pal up and borrow rings to test, 32,34,36,38.
I did my 38 on the leg strength I have climbing, and I was spinning out 36-11 flatland.
IMO, and as I stated, my experience is with 26 inch wheels, road/offroad/climbing.

good idea about the paling up.... wanna be my pal? or anyone else for that matter? btw, how do i know what 80rpm's is like? I'm not sure how to actually tell if that is my rpm when i'm riding. or is that just a given with certain gearing?

thanks.