Changing from 8-speed to 9-speed

Hello. I was wondering if anyone out there could provide some advice on changing a cassette. I currently have an 8-speed Shimano cassette and the cogs are worn, causing the chain to skip. I replaced the chain last week and was told that the new chain may be the problem. However, I had the cogs looked at was told that they were worn. I have an old custom made (steel) bike and I'm wondering if I can purchase a 9-speed cassette and place it on my bike. Do I have to worry about the width of the bike? I have gone to some local bike shops and they advise that I purchase a whole new bike.

Any help would be appreciated.

Assuming shimano,You can stick a 9 speed cassette on your hub,but you'll need shifters and chain to make it work right. The shops are populated by morons and just want to sell you a new bike.

IOW just get an 8-speed cassette and you're sorted.

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nick.

www.nickcoyne.com

Thanks for the info. I think my best option right now is to purchase an 8-speed cassette and call it a day.