8-speed vs. 9-speed cranks/chainrings?

[drewski]

Are 8-speed and 9-speed chainrings that different? Wider teeth? Will they end up with bigger gaps between the rings?

OK, here's some background so you know where I'm coming from . . . my trusty 8-speed Deore XT rear deraileur has bit the dust so I'm thinking of changing over to 9-speed for my MTB. Do I really need to change my chainrings to '9-speed' versions too? Or can I just change cassette, chain, shifter, deraileur?

If it makes a difference, it's a RaceFace Turbine crank and the rings were recently changed and the new ones' (RaceFace too) packaging clearly was marked in the '8-speed' check-box.

These chainrings weren't cheap so I'd rather not just chuck them after only a few hundred miles, but I don't want to just "give it a try" if I'm going to have a high probability of jamming my chain between rings while shifting under pressure on the trail because of spec differences.

Thanks!

 

[FasterthanU]

I can't believe no one has replied to this person's question. I'm looking for a similar answer. I need to know If I can switch my compact crankset with 8-speed chainrings to a regular crankset with 9-speed chainrings. How much of a nusiance will this possible cause? -FTU

 

[boudreaux]

I can't believe no one has replied to this person's question. I'm looking for a similar answer. I need to know If I can switch my compact crankset with 8-speed chainrings to a regular crankset with 9-speed chainrings. How much of a nusiance will this possible cause? -FTU

Why don't you start a new thread rather than digging up a long dead one? ...zombie. But ...yes.

 

[FasterthanU]

What's wrong with digging up an old one? Who are you working for?

 

[Doctor Morbius]

I can't believe no one has replied to this person's question. I'm looking for a similar answer.

Then please, allow me.

Are 8-speed and 9-speed chainrings that different? Wider teeth? Will they end up with bigger gaps between the rings?

OK, here's some background so you know where I'm coming from . . . my trusty 8-speed Deore XT rear deraileur has bit the dust so I'm thinking of changing over to 9-speed for my MTB. Do I really need to change my chainrings to '9-speed' versions too? Or can I just change cassette, chain, shifter, deraileur?

The official RaceFace answer is no. However, in a real world practical application it can be done and it's likely you'll never notice any difference - that is unless the old chainrings were worn and the chain skips. The gap inside of the chain will still be the same. The gaps between chainrings will be ever so slightly different. Seeing how your post was almost a year ago, my guess is you've already done somthing at this point.

I need to know If I can switch my compact crankset with 8-speed chainrings to a regular crankset with 9-speed chainrings. How much of a nusiance will this possible cause? -FTU

The official Shimano answer is - you guessed it - no. However, as long as your chainring bolts line up you can do this. Depending on the number of teeth on your old BIG compact chainring, you may have to move the front derailleur a tad upward on the frame. You probably don't want to go double compact to tripple standard. That could possibly require a different front derailleur to handle the extra chainring depending on what the bike already has on it. Tripples can do doubles, doubles can't do tripples. As long as you are just swapping chainrings you're in the clear.

Hey, at least you used the search function to try and find an answer to your question! Not enough posters do that.