8 & 9 spd front derr. interchangeability

[cantdog]

So I have an old 8spd front derr. laying around, and I cant find the X.gen front derr that is supposed to go on this build(x/9 build)...so the question is, can I use the old 8spd shimano front with an otherwise 9spd drivetrain? Will the cage be too wide?

[Brizn]

You shouldn't have any trouble running "an 8spd fd" with 9 in the back.

On one hand, the cage might be a little wider (per a slightly wider 8spd chain).. but you should be able to accomodate thru cable tension. On the other hand, the cage could be a little too narrow in that there's a bigger range of lateral motion with a 9spd cassette (as opposed to 8).

Again, it shouldn't really be any trouble, tho. Goodylucky.

[rmac]

I'm running an old xt 8 spd front der w/a 9spd rear der. I had to fine tune it, but once I got it right I've had no issues. I'd give it a shot, but as soon as you get the 8spd front der on & set up, you'll find the 9spd.

[macdaid]

I've got a similar issue.

I'm using an 8spd f-der (not shure 'bout that), and an 8spd r-der, with a 9spd cassette. Got the r-der stopped down to avoid the biggest gear in the cass.

No matter how much I adjustandtwiddle with it, I can't get the rear to shift consistently and smoothly while under load. Works fine on the stand, but then gets rough in application.

Intermittantly,
the chain either slips (bad chain, worn cass. ?) or chatters on the larger gears on the cass. This happens on the middle ring, as you might expect, buty also sometimes on the small ring.

I say intermittant because sometimes, like today, it hits the sweet spot and spins away happily.

I checked the chain with a guage (thanx Briz!) and it looks ok. Looked at the cass. before I installed it, and while it'snot brand new, there weren't any burrs, or other wear I could see.

Now this chain-width thing has me thinking. What is the correct width for a set-up like mine?

Or should I just pony up and get a new 8 spd cass & matching chain and be done with it?

Oh, and I also get some chatter on the front Der too... too narrow cage?

And today? the chain jumpedof the small ring, and got wedged between the ring and BB shell. Had to break the chain to get it out....

Say, does it sound like I'm complaining? Well I'm not. I was a beeeyou tee full day to ride, and i hit everything just right, and was prepared for everything that came along!!!

BTW, rmac, that's an outstanding avatar. Excellent combination of symbols.

[xmynameisdan]

The spacing between cogs on an 8 & 9spd cassette is different. You're using an 8spd chain on a 9spd cassette also? You're displaying pretty much what I would expect to happen. I really have no advice other than to pick up an 8spd cassette and maybe a new chain. SRAM makes very affordable 8spd cassettes.

[macdaid]

Dan,

Thanks for the input. The bike is such a kluge of parts from 2 diff'nt bikes, I wouldn't be surprised if there were compatablity issues.

Guess it's time to pony up.
I'll check out the Srams per your suggestion.

Gracias.

The spacing between cogs on an 8 & 9spd cassette is different. You're using an 8spd chain on a 9spd cassette also? You're displaying pretty much what I would expect to happen. I really have no advice other than to pick up an 8spd cassette and maybe a new chain. SRAM makes very affordable 8spd cassettes.

[Brizn]

hey | > /| \ | = , are you using an 8spd shifter as well? An 8spd shifter is probably gonna be indexed to an 8spd cassette.. Ie, it's gonna shift wider..

[macdaid]

Y'know,

It's an 8. Sound's like another nail in this cassette's coffin.

Here's the math for success:
8 shftr + 8 r-der + 8 cassette = smooth reliable shifting.

t 0r f?



hey | > /| \ | = , are you using an 8spd shifter as well? An 8spd shifter is probably gonna be indexed to an 8spd cassette.. Ie, it's gonna shift wider..

[macdaid]

If I put an 8 on the free-hub, I'm gonna need a shim too...

[Brizn]

Here's the math for success:
8 shftr + 8 r-der + 8 cassette = smooth reliable shifting.

t 0r f?Yea,.. now you got it.. Shifter, CHAIN, and cassette must match. Derailleur need only have a range of lateral motion such that it reaches all the cogs left and right. So in your case, you may use either an 8 or 9spd der, as you can simply 'limit' the travel. Derailleurs have continuous/infinite travel-- the shifter is interval. And don't forget the right chain width. Henceforthe:

8shftr + 8cass + 8chain / 8 or 9der = srs !

[macdaid]

Hmmm,

new cassette, new chain; mebbie I'll even put that old XTR on, since a 9 spd der stopped down to 8 will work w/an 8 spd shifter. It's still nice and tight, no play in the works...

Yea,.. now you got it.. Shifter, CHAIN, and cassette must match. Derailleur need only have a range of lateral motion such that it reaches all the cogs left and right. So in your case, you may use either an 8 or 9spd der, as you can simply 'limit' the travel. Derailleurs have continuous/infinite travel-- the shifter is interval. And don't forget the right chain width. Henceforthe:

8shftr + 8cass + 8chain / 8 or 9der = srs !