8 speed vs. 9 speed spacing...does it matter?

[BrettM]

K I need some help with this because I've gotten a couple different answers now. No guessing.

Is the only difference between an 8 speed cassette and a 9 speed cassette in the spacers or are the cogs actually thinner and thicker or teeth different? What I'm wondering is could I build a cassette with 8 speed cogs, but use 9 speed spacers so that it would work and shift normal and all that?

I finally found a place that will sell me just a 21 tooth cog for like 5 bux but only in 8 speed, and I won't run an 8 speed chain. Don't ask.

Anyone know?

[willapaj]

I'm pretty sure most of the difference is in the spacing... not so much the width of the cog. But, with narrower 9spd chains, the cogs might be made a bit thinner. So I don't know for sure... the only difference between 7/8 is the freehub must be longer, same spacing...
Why won't you use an 8spd chain?

[BrettM]

I've run every single Sram chain and the only 8 speed chain I'll use is the pc51 which they decided to stop making. I happen to like the pc99 even more and its readily available and lighter and all that. Aside from that I use a very fancy Sram shifter and it's 9 speed so I don't want a new shifter and all that. I also have a goofy theory that 9 speed chains are stronger than 8.

I called the 4 most reputable shops in Victoria. 2 said I would be ok. 2 said there is a difference in thickness of the actual cog and it would wear faster and might cause probs. Not impressed so far.

[hydroboy]

only the spacing is different. The chain has plenty of room for whatever cog. Think kingcogs, can be used with 8spd, 9spd, bmxspd chains. Dont worry about cogs, only spacing.

[BrettM]

I was told by king that you could use whatever chain you wanted. However I think I also remember someone saying they had some chain issues.

[tomacropod]

in order of thickness from thinnest:

9sp shimano road cogs
9sp shimano mtb cogs
8 speed cogs
king kogs.

the thickness thing is just a weight/wear equilibrium, as usual shimano chooses to be light and crap, but they will all be thin enough to run with any 9 speed chain.

- Joel

[RideManuals]

Has anyone tried the try-all 7speed cassete? and just wondering how many speeds are you gonna be running?

[BrettM]

and just wondering how many speeds are you gonna be running?

I run 6. I use a very light and actually pretty cheap off ebay sram road cassette as fake gears. It's lighter than dura ace and all that jazz and is like 30 bux off ebay or so? I wouldn't actually trust it. That's why I use one regular trustworthy cog for trials.

Now I was doing some more thinking on this subject. How can there be front chainrings for 8 or 9 speed chains but the rear cogs can be specific to only one???

Looks like I'm getting on the phone again tomorrow...

[AndyT]

Unless you are planning on racing the tour de france, don't worry about any of that bullshit.

[BrettM]

Im ridiculously paranoid aboots my drivetrain. I can ride with brakes that don't lock and everything else as shady as it comes. My drivetrain is just always in my mind. I actually own one of those stupid chain wear guage things. Surprisingly it has predicted 3 chain breaks in a row now.

You know how some people when doing a line have in their head hmm maybe my rear brake will slip...doesn't bother me. I'm way too busy thinking aboots that damn chain. Probably due to Metchosin Joe. I've seen him break way too many.

[AndyT]

Are you / they running BMX chains? No reason to worry about your shit, just put one on...

[BrettM]

Even on my bmx's I run a sram pc51. Except for my street bike because it won't fit the Macneil sprocket. Not a fan of them really.

Joe has tried every chain made. He's one of those people who can gap really far, but it has nothing to do with technique at all. Just pure power. He gets in this huge rage state and yells a bit and then just gives 'er.

[AndyT]

I can't see anyone breaking a bmx chain that has been properly installed, I'd just stick with rohloff imo.

[BrettM]

I don't think Joe every really broke many chains. Most times he would pull the cage off the pin sorta deal. This is with using the quick link so no one had touched it.

Jason just got a bmx chain on his bike and it felt pretty good. Unfortunately it would throw off my whole drivetrain jazz and its just not what I'm after. I know what I like, I'm just trying to get it a bit cheaper. More beer money is always a plus.