Bicycle Mechanics - Older Shimano 105 converting 6 to 7 speed freewheel?

Hello.

I have 12-year-old Cannondale with shimano 105 components. It currently has a 6 speed freewheel with 13-15-17-19-21-24 cogs. I would like to buy a 7 speed freewheel with 12 - 21 cogs. Other than replacing the shifters with a 7 speed index, will I have any problems making the derailer go an extra cog? There appears to be plenty of space for one more cog. If not what would other options be other than replacing the rear wheel, cranks, derailer, etc. Also, I've been out of cycling for awhile. What does SRAM mean? Any help here would be greatly appreciated. Thanks.

Tracy

It should work. Check the width of your old freewheel and the new one. They may be the same or close. Make sure you chain is the correct with for the new freewheel.

You can adjust the with travel distance on your derailure by adjusting the stop settings.

Before you buy the new freewheel, you can measure the derailure's maximum travel distance by setting the stops at their outside limits and then measuring the total available travel distance. Be sure that the setting for the inside (nearest the spokes) doesn't cause the derailure to rub against the wheel guard or go into the spokes. You are mostly interested in the adjustment of the outside limit adjustment.

I went from 5 to 7 speed with no problems.
Check out
http://www.argonet.co.uk/highpath/cycle_/faqs.htm

Sachs make the best freewheels. Much better than Shimano.

Thanks for the information guys. Any other input is appreciated

Tracy

You should always replace your chain when replacing a cassette or freewheel, if you have ridden those gears over 200 miles. No measuring of the der. travel is neccesary. Just install the new freewhell and adjust the der. when you shift through. It is alot easier that way.

Catsweat,
To answer one of your questions, SRAM doesn't actually mean anything it is just a brand name. Either SRAM bought Sachs or Sachs changed its name to SRAM, but SRAM and Sachs are the same. Someone correct me if I don't have this quite right.
Regards,
Raymond

SRAM bought Sachs. Now, does anyone know how you pronounce SRAM. I always say "ess-ram". Probably wrong, but that's what they get for having a name like that!

You are correct Rainman. SRAM bought Sachs. This is the reason for the imporovement in SRAM components.
Rider X I always pronounced it SS-RAM.

Tracy ,is your rear cogs a screw on type "cluster" or a "cassette" ??...

Originally posted by riderx
SRAM bought Sachs. Now, does anyone know how you pronounce SRAM. I always say "ess-ram". Probably wrong, but that's what they get for having a name like that!
You can learn everything about the company but the pronunciation at http://www.sram.com/about/history.html. Perhaps the pronunciation is a trade secret?:D

Buddy,

I can't really tell. the first cog (13) appears to screw on, but I'm not sure if the other ones do. Any easy way to tell?

Tracy

On a screw-on type "cluster" their is a dust cap recessed into the body with a splines protruding around it, with a "cassette" it has a lock ring,with splines in the centre of it and the axle sticking out and the lock-ring covers up the bearings dust cap...

Catsweat,
After your message yesterday, I went to harriscyclery.com to see what they had. They offer a couple of 5 speed Shimano freewheels that may do you. I think one was 12-22 or so, and they were only about $20. You might want to go look at their 5-speed and Ultra 6 freewheels (slimline to directly replace a 5-speed). Might be an acceptable alternative to a more expensive upgrade.
Regards,
Raymond

Thanks Rainman! I'll check it out.

Buddy,

The freewheel appears to be a cassette.

Cool, you need to get a 7 speed freehub body fitted,a 7 speed cassette(put on a new chain w/new cassette !),have your rear deraileur adjusted,you will probably need your dropouts spread wider,and new shifters,if you want indexed shifting,or you may be able to use your current shifters in the friction position..... now ask yourself is it really worth doing all that for an extra gear !?..:)