Is a 1998 XT rear der. 9 speed compatible?
Compatibility
- Thread starter BikeGeek
- Start date
yes, but because the eight speed chain is slightly wider that a nine speed, shifting performance might not be a crisp as with a nine speed rear derailluer. But then again I have also heard that performance is exactly the same as with a new derailluer. Either way you should try it, it will save you some money.
Based on my experience, I say no. I've heard you can make it work but I've never seen it work without constant attention and tweeking. PM Wrenchmonkey. He's one of my techs and he's been turning a wrench for 15 years. If there's a way, he'll know.
It'll work fine. The difference is the pulleys are a touch wider as is the cage. If you replace the 8spd pulleys with 9spd it should be the same. Might have to grind the pulley bolts to make them shorter. With 9spd cassettes the width across the 9 cogs is identical to the width across 8spd cassettes. The cogs are the same thickness too. The outside dimension of the chain is narrower. The chainrings have ramps and pins that stick out a bit farther to pick up the narrower chain. The front derailleur cage is slightly narrower too. I think the front spacing is the same as 8 spd.
Actually it not. The problems I always see is with the front der. The width is narrower enough to allow rubbing regardless of adjustments. Depending on how you adjust the front der. the rudding will move from spot to spot but will always be there. It servicing probaly 30+ bikes over two years converted in this way, EVERY SINGLE ONE had this problem. I have yet to see anyone overcome the rubbing.
Otherwise, its exaclty as Oldfart stated. The rear will match up just fine.
I think if you get a micrometer out you'll find the chainrings are spaced the same for 8 and 9 spd. The 9 spd derailleur cage is narrower and even with all 9 spd equipment its next to impossible to get no rub on that front derailleur across the usable range.
We remove all rubbing from 9sp DT's regularly. The key is to make sure the cable is sufficiently stretched to allow fine adjustemnts to hold longer. I'll check the width between 8sp and 9sp, though. You may be right. I still have never seen a 9sp conversion work, at least what I'd qualify as, properly.
The verdict is in.
The width difference between 8sp xt and 9sp xt is just under 1 tenth of an inch, measured at the same point on each unit, the bottom of the cage. (Our micrometer isn't in metric.)
Additionally 8sp chains are 7.44 mm while 9sp chains are 6.4 mm (quoted from "Quality".) If you take the difference in width between chains and add it to the difference in width between Der cages you get a degree of difference that accounts for the inability to elliminate dragging of the chain through the cage within the usable range.
What this means is that you can use 8sp conversions but it will not pass smoothly through the front der.
The width difference between 8sp xt and 9sp xt is just under 1 tenth of an inch, measured at the same point on each unit, the bottom of the cage. (Our micrometer isn't in metric.)
Additionally 8sp chains are 7.44 mm while 9sp chains are 6.4 mm (quoted from "Quality".) If you take the difference in width between chains and add it to the difference in width between Der cages you get a degree of difference that accounts for the inability to elliminate dragging of the chain through the cage within the usable range.
What this means is that you can use 8sp conversions but it will not pass smoothly through the front der.
Ok, your wrong. It will work. I have used it for about three months. The only reason I switched back to eight was I bend the frame on the other bike and had a chance to build a bike from the ground up. If you a concerened with chain width, then you should notice that a nine speed Sram chain between the widths of Shimano's eight and nine speed chains.
Sorry when I said spacing is the same I was refering to chainring spacing. But don't quote me I'm going by what a trusted mechanic told me. He also says on the rear the greater float of the 8 spd top pulley will slow shifting down a touch which makes sense. Yes I know the front derailleurs cage is narrower on 9spd. And it is a bitch to get it to not rub in all usable gears. The narrow spacing makes the drivetrain less tolerant to chainlines that aren't perfect or close to it.
is that it will work, but not well. If you can't afford to get a new der, or just don't want to, you can use it. But I say get the new one, it will work better...