KMC Z-51 IG/HG 6/7 Speed ATB Chain
 

Guys/Gals:
What does the IG/HG stand for in the following product description:
-KMC Z-51 IG/HG 6/7 Speed ATB Chain ( http://mec.ca/Products/product_detai...=1187997133497 )
I am looking to put this chain on a 12 year old Miyata GT 600 with a 7 speed freewheel. Is this chain likely to be compatible?

I believe it means that they are compatable with Shimano's IG and HG systems (hyper glide, interactive glide) and that they are sized (width wise) for 6 or 7 gear cassettes. 8,9., & 10 speed cassettes require skinnier chains to cram in those extra cogs.

I think it will work for you. these chains are designed to make use of the ramp system on the HG/IG systems. Does your Miyata have ramps on the cassette cogs? It will work whether there are ramps or not, but it will work better if there are shifting ramps.

The real issue is how worn is your old cassette. A new chain on an old cassette will often not work, because the cogs have worn and will fit only a chain which is stretche. It is always recomended to change the chain and cassette simultaneously, so they wear together.

I put exactly the same chain on my 86 RockHopper (3X7) and it worked fine. Better than the old chain that had some semi-stiff links. It seems to shift a little better with my friction shifters than the old chain.
BTW, I paid $6 at our local "Outdoor & Fitness" store.

Thanks guys. The Miyata does not have any ramps. I tried changing the freewheel as well but it is a Suntour 4 notch. It pretty much refused and efforts on my part to remove it. I put the chain on the bike and I am getting some phantom shifting of the type that Sheldon Brown's website suggests is due to cable tension rather than worn cogs (but I'm not sure). Basically I get an autoshift into a new gear rather than a chain skip with no gear change.

Scratch that. I am getting same-gear chain skipping. I might try a destructive freewheel removal. I have been using the chain for about 5-10 hours. It still passes the 12in ruler test (rivets line up). Is it likely that the skipping and phantom shifting has caused enough wear that I should replace the chain again if I get a new freewheel?

I gave it one more shot with a vise and got the freewheel off. Time to find a new one.