Faster the better - 6spd cassette help

william79

Hi everyone. I'm new to the forum & this is my first post; hope you can help.

I have been commuting since May '07 on my trusty Raleigh Pro-Race (circa early 1990's, has been in hibernation for 10yrs ). As my fitness has increased so has my desire for speed....

It currently has a 52t chain ring at the front (double rings), with 14-(28?) at the rear. It is only a 12 speed bike (Shimano SIS), but I only use the top 3 gears to climb moderate hills.

I would like to upgrade the rear cassette to achieve the highest gearing possible (11-24t would be OK). A single speed would be too slow & I need to retain some gearing.

The bike has a 6 spd rear cassette, the most widely available seem to be 7+, but I have found a 6spd upgrade online. I'm hoping for a straight swap to increase the speed, instead of increasing the number of gears.

Has anyone got any tips for the upgrade. Recommend any tools for the job?

Thanks!

dondare

Ask Sheldon.

http://sheldonbrown.com/freewheels.html

fossyant

Is it a casette or freewheel.

If cassette you can buy a 7 speed one and re-use the 6 speed spacers and ditch one sprocket - just watch out if your block needs a locking bottom sprocket, or uses a hyperglide lockring - as they are different. Hyperglide sprockets (HG) will fit the older IG cassette bodies.

You would be better getting a closer ratio block - 11won't fit unless it's a hyperglide body. To be honnest a 13 is probably better, just learn to spin more - you should be pedalling 80-90 rpm anyway..... your current block probably goes 14-16-19-22-25-28 or something similar.

Probably better with 13,14,15,17,19,21 and maybe a 39 inner (if fit) or 14-15-17-19-21-23 - don't be too tempted to get the smallest bottom gear as your ratio jumps will be too much to get to the top gear.

Better go take a look...

william79

Thanks, I'll look into this.

dondare

BTW, if you want to go faster then learn to pedal faster. Your existing set-up gives you a top of 100 inches which should be enough.

nce21

a 6 speed is almost certainly a freewheel not as freehub. That means for a simple change you won't be able to just replace the cassette for a different 6 speed one, you need a freewheel instead. To get a higher top gear then you will probably need to go to a 7 speed 11-34 mega range as other freewheels don't generally have smaller than a 13 or 14. Then your sis shifters will have to be run in friction mode.