Shimano Deore rear hub and Shimano CS-HG20-7 Sprocket

[Lighttower]

Hi Everyone!

I hope you can help me. I bought a new 26" MTB rear wheel online and it has a Shimano Deore hub, I was trying to attach a new CS-HG20-7 Shimano Hyperglide Sprocket (with 7 gears and 12-28 teeth), but it seems the "Sprocket socket" (I am not sure what it is called) is slightly longer then needed, I could theoretically fit another gear cog.

Are there some kind of "spacers or washers" available? If yes, what are these things called?
Or did I mess something up? Is this normal?

I am new to bike repairs, I moved to a new city and all of the local bike repair shops do either horrible work, are expensive or sell really cheap parts.

Thanks for your help.

[Painkiller]

what model is your Deore hub? most would use a 4.5mm spacer behind the cassette
http://www.outsideoutfitters.com/p-27258-problem-solvers-cassette-spacers.aspx?variantID=89709&gclid=CJvZh-qSm8kCFQQPaQodFE0BgQ

your bike shop, however bad may have one in stock. That may be cheaper than the shipped online price. Give them a ring and ask for a price. Getting it the same day is nice too.

[Lighttower]

(11-18-2015, 07:45 PM)painkiller Wrote:  what model is your Deore hub? most would use a 4.5mm spacer behind the cassette
http://www.outsideoutfitters.com/p-27258-problem-solvers-cassette-spacers.aspx?variantID=89709&gclid=CJvZh-qSm8kCFQQPaQodFE0BgQ

your bike shop, however bad may have one in stock. That may be cheaper than the shipped online price. Give them a ring and ask for a price. Getting it the same day is nice too.

Thank you very much for your reply! I will go today and visit all of the local bike shops, one of them probably has one of these. :-)

[nfmisso]

With the 4.5mm spacer behind the cassette - you might have to remove the rivets or screws that hold the cassette together to get everything to fit.  

I found the a spacer from inside a 7 speed cassette (about 3mm) is close enough to use without removing the rivets/screws from the 7 speed cassette to use on a 8/9/10 speed freehub.

I have done it the "correct" way with the 4.5mm spacer and the cheater way.

[Lighttower]

(12-03-2015, 08:34 PM)nfmisso Wrote:  With the 4.5mm spacer behind the cassette - you might have to remove the rivets or screws that hold the cassette together to get everything to fit.  

I found the a spacer from inside a 7 speed cassette (about 3mm) is close enough to use without removing the rivets/screws from the 7 speed cassette to use on a 8/9/10 speed freehub.

I have done it the "correct" way with the 4.5mm spacer and the cheater way.

Thank you for your reply.
I did measure it several times and I had the feeling a 3mm should be able to do the job just fine.
I tried to buy both, but I could only find the 3mm ones, so I tried it and it fits and works like a charm. I've already done around 85-100km of commute with it and it shifts perfectly. I don't see (or hear) any problems either.
I guess we solved it together. :-)