10-speed cassette alignment

My cyclocross bike uses a Shimano Tiagra 10-speed so I purchased a 105 10-speed cassette for the Neo to be able to quickly transition from trainer to ride to trainer (cassette is same part# but bike has 11-32 vs new cassette having 11-28). I attempted to purchase a 1.85mm spacer which I determined thru lots of web surfing to be what is needed to use a 10-speed on an 11-speed freewheel. The bike shop couldn't find the 1.85mm spacer I ordered from them so they gave me a 2.0mm one. 

After getting it all together and readjusting my rear derailer, I'm finding that there is still grinding on the last few small cogs. All good on the larger ones. Could this be due to the 0.15mm difference in the spacer? 

I did put a new chain on as well. Not sure if this be an influence as well...

  • I finally got a 1.85mm spacer that does position the 11T at the same position on the hub as it is on the bike wheel. So the contact I get with the two small cogs (front and back) is the angle being a bit too much to allow full clearance. Perhaps due to the new chain not being worn in yet? But as with you, I'll just avoid the extreme gears for now and work on improving my shifting shifting techniques (which are being challenged on the European mountains in the Tacx film rides that have a lot more vertical than I see in real life!)

  • No. Im using a MTB fixed to the Neo.