Commuting - 7-speed hub gear conversion

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 : 7-speed hub gear conversion


jumbolugs
09-08-04, 03:31 PM
I'd like to replace the freehub/derailleur on my old hack bike (it's an old road/touring frame) with a 7-speed hub gear, probably Shimano, and with flat bars.
I'm not sure what you need to do this - apart from getting a new rear wheel built around a 7-speed hub, will I also need any special braze-ons on the seatstays to handle the cable-routing etc? Also what type of shifter do you use for a 7-speed hub?


Bockman
09-08-04, 05:31 PM
How many cogs on your current freewheel?

Dave

froze
09-08-04, 10:12 PM
I'm confused; are you wanting to change out a freewheel to a 7 speed cassette system? Why when you can buy a 7 speed freewheel and not go through all the hassle and cost of a new hub, cassette, derailleur etc? A 7 speed freewheel has just as many gears as a 7 speed cassette!! This is an older bike, save your money.


jumbolugs
09-09-04, 12:30 AM
Bike currently has Shimano freehub with 7-speed cassette

jumbolugs
09-09-04, 12:34 AM
Think you misunderstand what I am trying to do.....I want to get rid of my cassette/derailleur system altogether in favour of hub gearing! The intention is to use the bike purely for commuting and winter touring

jhershbine
09-09-04, 06:31 AM
Check with the master at www.sheldonbrown.com, he has sound advice on internal hubs and many other conversions.

RainmanP
09-09-04, 06:31 AM
Post your request over in Bicycle Mechanics. Be sure to specify that you are wanting to switch to an internally geared hub. Do a search first since this topic has been discussed before.

PaulH
09-09-04, 06:37 AM
The main problem you will have involves the vertical dropouts. You will have to either 1) install horizontal ones, 2) machine the dropouts so that chain tension can be adjusted, 3) install a thing called a singulator, which is an idler sprocket that maintains chain tension. Sheldon Brown has some info on these hubs:
http://www.sheldonbrown.com/internal-gears.html
Also check his singlespeed page to learn about dropouts.

I considered doing the same thing with my old Specialized Crossroads, but concluded buying a new bike would be more cost effective. You might consider buying a singlespeed frame and moving your components over.

Paul

Dahon.Steve
09-09-04, 06:48 AM
The main problem you will have involves the vertical dropouts. You will have to either 1) install horizontal ones, 2) machine the dropouts so that chain tension can be adjusted, 3) install a thing called a singulator, which is an idler sprocket that maintains chain tension. Sheldon Brown has some info on these hubs:
http://www.sheldonbrown.com/internal-gears.html
Also check his singlespeed page to learn about dropouts.

I considered doing the same thing with my old Specialized Crossroads, but concluded buying a new bike would be more cost effective. You might consider buying a singlespeed frame and moving your components over.

Paul

If the bike doesn't have horizontal dropouts, forget it and get another frame. Or better yet, buy a used 3 speed or search Ebay for "Shimano Nexus" for bikes that use this hub.

DanO220
09-09-04, 02:16 PM
If you are curious about internally geared hubs find a LBS that stocks them and take a test ride. I did this before building my own commuter, and ended up choosing a Sram S7 speed hub over the Shimano Nexus. One thing the Sram hub offers is a quick release for the shift cable, which you'll realize is a godsend as soon as you get your first flat. I did not convert a bike, but rather built one from the ground up using a Surly CrossCheck with semi horizontal drop-outs.

I liked the bike alot for my commute. But as soon as I began going out on longer rides, say 30 miles, and climbing some serious hills, I became a bit disenchanted. The hub will make your bike about 2.5 lbs heavier than necessary. And the Sram S7 exhibited so much mechanical friction in 1st and 2nd gear that they weren't much good for climbing. I understand this is the case with most, if not all internally geared hubs.

But like I said; around town the Sram S7 was great fun and looked good as well. Recently though, my life began to get a bit complicated, so I wanted my bike to be as uncomplicated as possible. So I converted my CrossCheck to a single speed. I'm diggin' it. If I ever need more options I have a 28/38/48 triple chainring and a Melvin tensioner standing by.

Just some thoughts from someone who's been there. DanO