10sp-9sp Compatibility question

doulos said:

Sorry if I missed this in a search but is there anyway to use a 9 sp Shimano XT RD and 9 speed cassette with a 10 Ultegra STI. This would just be for occasional hill climbing century bailout gears. I currently have a R700 compact up front. I have the 9 speed lever but am being lazy.

Thanks Tim

See here:
ctc.org.ukDesktopDefault.aspxOpen ↗

n

Those wheel adaptors seemed a good idea

http://www.ctc.org.uk/DesktopDefault.aspx?TabID=3946

Not clear whether when you use a 9 speed Shimano [censored] with a 10 speed Shimano cassette as to whether you can use all 10 gears, or only 9 of the 10 gears.

I'm not sure from the link either but it's probably worth a try. Thanks

mikesbytes said:

Those wheel adaptors seemed a good idea

ctc.org.ukDesktopDefault.aspxOpen ↗

Not clear whether when you use a 9 speed Shimano [censored] with a 10 speed Shimano cassette as to whether you can use all 10 gears, or only 9 of the 10 gears.

You've still only got 9 positions on your shifter - reckon you'd have to choose which end you were going to lock out.

artemidorus said:

You've still only got 9 positions on your shifter - reckon you'd have to choose which end you were going to lock out.

So, with thre rare exception, there isn't a lot of point in doing the mod.

doulos said:

Sorry if I missed this in a search but is there anyway to use a 9 sp Shimano XT RD and 9 speed cassette with a 10 Ultegra STI. This would just be for occasional hill climbing century bailout gears. I currently have a R700 compact up front. I have the 9 speed lever but am being lazy.

Thanks Tim

I wanted to go the other way ie: I had a 9 speed shifter and RD and a 10 speed cluster. I can get it working but the teeth on the cassette are closer together on the 10 over the 9 so a 9 chain is a bit wider and just fits in between the teeth. With you however, if you have a 10 chain ( bit thinner than a 9) it should fit with plenty of clearance however the other problem will be the indexing which I'm not too sure about but gut feel says it will be like mine in that every time you click up or down a gear the RD is going to index across a mickey hair less than what the cassette wants ie: chain will be slightly misaligned. And all those mickey hairs eventually equate to a big fat misalignment at the end of the shifting of about 1mm. It's not right but does work. I just bought a new cassette cause I didn't like it. You however would have to fork out a bit more for STI's. Best of luck.

mikesbytes said:

ctc.org.ukDesktopDefault.aspxOpen ↗

Not clear whether when you use a 9 speed Shimano [censored] with a 10 speed Shimano cassette as to whether you can use all 10 gears, or only 9 of the 10 gears.

You can do both.

To use a 10s shifter with a 9s cassette, anchor the RD cable in the "Old Dura-Ace position" - ie. 9 o'clock (assuming that the normal anchoring position is 6 o'clock). I use this combination on my road bike effectively. My reasons were thus:
1) I wanted the thinner feel of the 10s shifter hood without having to upgrade the entire drive train;
2) 9sp is theoretically more durable than 10sp anyway;
3) spares are cheaper; and
4) I don't need the extra cog on the back.

To use a 9sp shifter with a 10sp cassette (although you aren't able to access once gear - you'll need to decide which one you want to lock out, hence the "shortened cassette" key), anchor it at 3 o'clock (assuming the normal anchoring position is at 6).

The diagram/photos under "Old Dura Ace" and "Hubbub Shimano" show this quite clearly - at least to me.

n