General Cycling Discussion - Singlespeed front - Multispeed rear

Hi,

This may be a somewhat unusual request.

Ideally, I am looking for a bike that has a single chainring upfront, and multiple gears at the rear. The single chainring upfront would be moderatly sized and there would be 5-10 gears at the rear. The rear derailleur would be able to sweep through all the gears relatively smoothly without too much cross-chaining. Are there any bicycles currently on the market with a drive train like this, or would I have to go custom?

I am also willing to buy a bike with multiple chainrings upfront and remove the front derailleaur and shifter, and do the modification to a single speed crank, but I would rather buy the bike as per my specs. I would also be open to a triple chainring bicycle that could hit all the gears in the back relatively smoothly without cross-chaining when the chain is on the middle ring.

The most important feature is that the bicycle can hit all the gears in the rear, smoothly, without adjusting the front.

Any suggestions?

Thanks!

not too unusual of a request really...
whether to go custom or not depends on the type of bike you want.
Most "downhill" mountain bikes come this way
Many commuter bikes, crusisers and hybrids come with a single ring up front and externally and/or internally geared rear hubs
Alot of guys swap the outer chainring on their cyclocross bikes for a chainguard and use 9 gears without any shifting problems or extreme chain angles.

If for whatever reason you can't or don't like to shift in the front, you don't really need a special bike with no front shifter. Adjusting the "limit screws" on your front derailleur can effectively "lock out" any movement of the front derailleur, effectively making it a chainguide instead of a shifter. I say find a bike you like, and if it has a double or triple crankset, perform this simple adjustment instead of being limited to the models that come with a single front ring.

I had a more widely spaced set of cogs installed on the rear. The small one is slightly smaller that OEM, and the large one is a bit larger. Sorry I don't have the specs, but I ended up with a very nice 9 speed - with granny on the bottom and overdrive on the top. We have hills around here, but mostly I'm in the middle chain ring. I forget the installed price, but it was way under $100.00.

Would an internally geared hub do the trick instead?

I trained with a guy all summer that ran a 48T front with a 9-speed rear on a cyclocross frame.

I think there are others offered off the shelf, but one that came to mind is the Bianchi Castro Valley.

http://www.bianchiusa.com/607.html

Okay, so you want a single or a triple, but not a double. What do you have against doubles?

Honest question: why do this?

guess it really depends on what you're trying to accomplish. If the goal is simplicity on a bike for commuting, or knocking around, and you don't need a wide range, I'd go with with a bike built with a Shimano Nexus internally geared hub. Thus, no crosschaining issue, no derailleurs. Only 1 cog to clean. Can shift stopped. http://www.sheldonbrown.com/internal-gears.html

I think there are others offered off the shelf, but one that came to mind is the Bianchi Castro Valley.

http://www.bianchiusa.com/607.html

Hi Everyone,

Thanks for the great suggestions! The reason I want this is, is for simplicity. I would prefer to have the single crank upfront rather than locking out a double or triple, just for weight and aesthetic issues. Does anyone else have any more "off-the-shelf" suggestions. Looking for an all-round/commuter bike rather than something hardcore downhill.

Otherwise, what would be the rough cost to have an LBS do a double/triple to single conversion assuming I want decent components?

Thanks again!

Thanks for the great suggestions! The reason I want this is, is for simplicity. I would prefer to have the single crank upfront rather than locking out a double or triple, just for weight and aesthetic issues. Does anyone else have any more "off-the-shelf" suggestions. Looking for an all-round/commuter bike rather than something hardcore downhill.

An all around commuter bike will be substantially heavier than a road bike even with one chainring. Here is one example of an off the shelf product with a rear internal 7 speed hub and a single chainring upfront. This bike is close to 40lbs, but would be an excellent utility bike.

http://www.fujibikes.com/2007/bikes.asp?id=367&subcat=3

this is what you're looking for. Unfortunately I don't know of anybody that's makes the equivalent off the shelf.

http://www.sheldonbrown.org/raleigh-international/images/01.jpg

http://www.sheldonbrown.com/harris/bianchi.html

http://www.raleighusa.com/items.asp?deptid=6&itemid=305

If you wind up with a double or tripple, I'd leave it alone if it is working. If you want to convert to a single put the chainwheel in the crank position that aligns best with the rear gears.

A standard road triple converts easily, and is very common. Many bike shops will not have "stock" a bike with a single front crank. However, here's how you do it.

1. Have the inner and outer chainrings removed.

2. Replace the outer chainring with a Spot brand aluminum chainguard.

3. On the seat tube mount a Third Eye Chain Watcher, or a Deda Dog Fang.

4. Replace the left brifter with a brake lever.

5. E-bay the brifter you just removed. The chainrings too.

I did this for a friend...it works.

Go super pure with a unicycle.

My suggestion is a Rohloff rear hub!

14 speeds and NO DERAILEUR!!

just a thought...;)

http://www.ransbikes.com/2Whatsnew07.htm
CITI (new model)
From the site:
"The Citi uses the curved tube styling of the Cruz with the Dynamik frame geometry. The concept of the bike is to provide a simpler bike, only 9 speeds, with fat tires to handle the ill maintained streets, and float over softer surfaces. I use this bike as a chaser after a hard ride. You can push this bike to a fun cruise speed, since it is light and responsive. But you will never feel guilty about taking it easy due the cool styling. The bike is a blast, doing bunny hops, and riding over whatever you dare, seems to be little challenge for the tires or bike. The B-37 bars are called modern day “paper boys” and functions the same, allowing you a more upright position on the longer reach frame geometry. They are wide enough to stand and ride. You gotta love the Big Apples, simple gearing, and looks of this bike and the cool Ti-Rose and Metallic Red colors. • 9-speed for simple gearing
• Cruiser styling
• Fat tires
• B-37 bars, modern day “paper-boys
• Comes in two colors Metallic Red and Ti-rose MSRP $1195"

Are you looking for something like this?
Trek Soho (http://www2.trekbikes.com/bikes/bike.php?bikeid=1036000&f=20)