Bicycle Mechanics - loose cassette cogs

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View Full Version : loose cassette cogs


EEEEDNr
12-13-09, 09:22 PM
I was given a 90's Specialized Epic Carbon as a gift. It is 7 speed with Shimano 105 components. The cassette was dirty when I received the bike so I decided to take it apart and clean it. Upon reassembly, the cogs can wiggle on the freehub body when tightened to spec (40 NM or 30 ft lbs) . Unfortunately, I don't remember if they were loose to begin with. The cassette is a Shimano hyperglide possibly model hg-70. (hg manual here (http://techdocs.shimano.com/media/techdocs/content/cycle/SI/SI_0099A/SI-0099A-001-ENG_v1_m56577569830690337.pdf)). I don't seem to be missing any parts or have any leftover sitting around. Does this mean my cassette is worn and needs to be replaced, or am i doing something wrong?


reptilezs
12-13-09, 09:30 PM
what rear hub are you using. you might be missing a 4.5mm spacer that goes behind the cassette if it is a 8/9spd hub

EEEEDNr
12-13-09, 09:58 PM
My hub is a 105 model fh-1055. I believe it is a 7 speed hub because the movement is so miniscule, but the cogs are not tight. The smallest cog is 11t and it has 'bite marks' from the lock ring. I have never used a freehub/cassette assembly before, only freewheels so I don't know if these marks are normal. My guess is the lockring compressed the 11t cog enough to alow for movement. I have taken pictures of the hub, the 11t cog, and the order of assembly. Phone pics are the best I can do for now.


Jeff Wills
12-13-09, 10:57 PM
My hub is a 105 model fh-1055. I believe it is a 7 speed hub because the movement is so miniscule, but the cogs are not tight. The smallest cog is 11t and it has 'bite marks' from the lock ring. I have never used a freehub/cassette assembly before, only freewheels so I don't know if these marks are normal. My guess is the lockring compressed the 11t cog enough to alow for movement. I have taken pictures of the hub, the 11t cog, and the order of assembly. Phone pics are the best I can do for now.

I think you got all the cogs and spacers, but if the smallest cog isn't put on correctly, you can tighten the lockring and still have the cogs rattle. Check to make sure the arrow on the smallest cog lines up with the wide notch on the cassette body. It's easy to offset the splines by one notch and have the small cog hang up on the top of the splines.

DannoXYZ
12-14-09, 12:32 AM
Your cassette body is not the correct type for a 11t top-cog. That can only fit on Hyperglide-C bodies with the tips of the splines shortened. That's because the 11t cog is so thin that the grooves for the splines cannot go all the way through the cog. If you look at the outside of the cog, you'll see that it has a flush outer surface. The tips of the splines on the body must be shortened to allow this 11th cog to slide further up the body.

You have the cassette body in the middle of this picture:
http://www.sheldonbrown.com/images/k7hub-3-styles.jpg
http://www.sheldonbrown.com/images/k7hub-3-styles.jpg

You need the cassette body on the left of this picture (2 generations newer than what you have):
http://www.sheldonbrown.com/images/2k7-bodies.gif
http://www.sheldonbrown.com/images/2k7-bodies.gif

What you can do with your existing freehub body is to take a Dremel tool and grind off the 1st thread or two on each spline to allow the 11t cog to slide on further. Don't forget to tighten the lockring down to the recommended torque.

EEEEDNr
12-17-09, 11:58 AM
Studying the picture, I have the hyperglide/uniglide compatible freehub body with threads on the inside and out. It also has the wide spline. On the end the threads are tapered. This tapered edge mates with the 11t cog as it is also tapered. Should I have to grind it down when it is supposed to be hyperglide compatible and my cassette says hyperglide on it? Will grinding the threads affect the use of other cassettes not using an 11t cog?

jds108
12-17-09, 12:21 PM
"If I grind the threads down, will I have problems with other cassettes not using an 11t cog?"

probably not. You would be better off looking for a 12t cog to swap out for the 11t before you resort to the grinding solution.

DannoXYZ
12-17-09, 06:42 PM
No problems with grinding the outer threads on the freehub body because the only thing that uses those threads is the spin-on top cog on Uniglide cassettes. Unless you're planning on using Uniglide cogs any time soon in the future, the threads won't matter to you. Actually, you're only removing 1-2 threads, so it'll still be possible to thread on a Uniglide top-cog if needed.

As to the end of the threads versus inside of the 11t cog, it's not just the shape, but overall length of the spline that matters. Notice that the splines on the HYPERGLIDE-C cassette body that's used with the HYPERGLIDE-C 11t cog is shorter in overall length than the standard Hyperglide body? You can measure the required spline-length yourself by stacking the cogs & spacers upside down by themselves (11t cog on bottom). Then use a depth-gauge on a set of calipers and measure down to the inside of the 11t cog. Compare that measurement with the length of the splines on your existing freehub body and you'll see what the difference is and how much you need to grind off. You need to see some actual NUMBERS for this to make sense. An engineer cannot build a bridge across the river without knowing exactly how wide it is.

I've done this at least 100x, it's pretty simple. You've spent more time typing and asking questions about this than it would actually take to do the procedure.

operator
12-17-09, 09:21 PM
You can use HyperDrive-C cassettes on conventional bodies by adding a 1 mm thick spacer to the body before installing the cassette. This is a standard spacer commonly used for fine tuning chainline with conventional freewheels. It may be necessary to add a spacer to the right side of the axle in some applications, especially if you wish to make the wheel interchange with other wheels without needing to re-adjust the rear derailer.

Jeff Wills
12-17-09, 09:43 PM
You can use HyperDrive-C cassettes on conventional bodies by adding a 1 mm thick spacer to the body before installing the cassette. This is a standard spacer commonly used for fine tuning chainline with conventional freewheels. It may be necessary to add a spacer to the right side of the axle in some applications, especially if you wish to make the wheel interchange with other wheels without needing to re-adjust the rear derailer.

+1. This worked for me, and I didn't even have to respace the hub. It's been a while since I did this, though.