drivetrain issue - 9 speed chain on 8 speed cassette?

Hi,

I think I am cursed as my Hot build is fighting me every step of the way.

Anyway, current issue is the new M950 front derailleur I bought doesnt fit the bike. The tube on the Hot flares out at the bottom into an oval shape and the design of the M950 means it has to be mounted lower right where the tube goes oval.

But, I also have an M953 which will fit as its a different design that will allow the standard higher mounting. However, its a 9 speed derailleur and the rest of my set up is 8 speed. Also, the M950 cranks state IG chain only.

So, long story short, my plan is to use the M953 fr derailleur and therefore get a 9 speed chain that would fit.

Question is, will this work with the 8 speed cassette and also will a SRAM chain work with the IG only cranks as i dont think they made a 9 speed IG chain :? ?

From looking online I get conflicting answers, but they sway towards it working.... but I trust the knowledge on here a lot more.

Help/advice greatly appreciated.

Hot is too much trouble, sell to me.

Chain, derailer will work.

9spd chain works perfectly well on a 5/6/7/8/9 spd cassette.

front mech trouble occurs with mixing shifter/ mechs as different shifters pull different amounts of cable. This is a pain to solve and can take ages.

The only time a chain will actually cause shifting issues is when its the wrong width for the cassette spacing - i.e: a fat 8spd chain on a skinny spaced 9spd cassette

Or, you could just use your 8 speed chain with the 9 speed front mech, just as you can use the 9 speed front mech with an 8 speed shifter.

legrandefromage":3194v9vr said:

front mech trouble occurs with mixing shifter/ mechs as different shifters pull different amounts of cable. This is a pain to solve and can take ages.

Click to expand...

Yep - i'm finding that out. Thought my probs were down to mismatched cranks and axle length, but apparently there's more to it :roll:

Cheers for the advice guys.

Went to fit the M953 mech and realised that its a Top Pull, so cant use that either!

I still have the old XT mech that came with the bike that I will fit for now until I can work out a solution. Ideally I want an 8 Speed XTR derailleur, but it looks like the M950 range isnt going to work for me due to the strange tube shape. I was looking at the e-type (e-stay) but again, don't think that works with the frame.

What options were available on the M900 derailleurs? are they easy to get hold off?

pics always help

Okay

Explanation by pictures. Please excuse the first one, but I hope it illustrates my point.


You can see that the front to rear profile of the seat tube flares out at the bottom, but when looking from the side it seems to be the same width all the way through - so the main part is round and the bottom is ovalised.

The red line is where the Fr Derailleur normally sits, just above the bottle cage mount.

The Blue line is where the XTR FD-M950 needs to sit as its a top swing, low mount derailleur. Obviously the round clamp doesnt sit on the oval tube.


FD-M950


A stock photo of the FD-M953 that I thought would work, but mine ended up being top pull (rather than bottom as pictured)... Grrrr..


A stock photo of the FD-M735 that I got with the bike, that will work, but I'd rather have XTR.

I can get another M953 with the correct bottom pull (as pictured), but its 9 speed and also its another $70...

Looking at the pictures of the FD-M900 I think it may work. Just need to get hold of one. Will probably put an ad up in the wanted section.

Just re-read this and it seems I have fallen into my usual trap of answering my own questions!

Sorry!