7-speed / 9-speed conversion question
 

Hi Guys,

Sorry to ask what is probably a stupid question that has been asked before.

I am thinking of updating a 1989 Trek 660 to 9-speed:

1) Will the 600 RD handle 9-speed?

2) Will a 9-speed cassette fit on the free hub?

Thanks as always,

RFC

I'll take a shot, and show my ignorance, since I've done just that...., but I changed out wheels.

1) Yes, in general, the RD will do what the shifter tells it to, if it has the range of movement.

2) Maybe, for an '89. Measure the width of the gear cluster, or don't and just try it. 50/50 chance.

Your freehub body is 4.5mm too narrow to accept a nine speed cassette. You can get eight speeds by using a nine speed cassette minus one cog, nine speed shifters and a nine speed chain. It's probably not worth it. Seven is enough.

Anything over 7 speeds and you need to change the Free Hub body to a longer one.
You'd also need a 9 speed chain.
If you have friction shifters, you can still use them. If indexed, you have to change them.
I'm not familiar enough with a 600 RD to know if it's index compatible.

1) Maybe
2) Probably not

It would help if you actually said what model RD you are talking about, and as I'm sure you are aware, the spacing is not the same (130 vs 126).

1. YES.
2. Do you see a noticeable gap between the wheel and the cassette? The answer to THIS question will be the answer to YOUR question. Palm reading over, now pay me $5.

Yes, there is a one spacer gap. Is this enough?

Why not.....
 

Why not just get a 7 sp. cassette with the gear range you want? Just check the max tooth size of the big (low) cog that your r. der. will handle.

How are you doing the upgrade? Just buying a 9-speed wheel and throwing it in?

1. Should work fine, as long as the RD has enough travel, and isn't worn out/sloppy. Downtubes will shift friction, or you could find some 9-2peed downtube levers.

2. It's possible that it might drop in with no problem, or with a slight bit of finessing(spread the dropout a bit by hand). Can only find out by trying it. Worst comes to worst you can always have the frame coldset.

ok... I did this myself with a pre-ultegra full 600 equipped Rossin ... AKA 6400

WITH the 600 DT shifters set to friction, you only get enough cable pull to move the RD through 8 of the 9 gears. 600RD has plenty of motion to go through all the gears, but you need a shifter that can actually pull the cable through the entire range.

So just put 8 of 9 on the 600 free hub since the 9th gear is out of range with the 600 DT shifter anyways.

or, if you're using a 130mm spaced modern 8/9/10 free wheel then rearrange the cassette to the 8 gears you want and put the extra on the inner side. My cassette goes 13-14-15-16-17-19-21-25-23 and the 23T is locked out both by RD limit screws and cable pull.

Thanks all. Good advice.