aprofromindia

I have an Ultegra 6700 groupset and used with Shimano WH RS10 (8,9, 10 speed wheel) with much satisfaction. Had to migrate to a Shimano RS100 (11 speed wheelset), with a Shimano 6700 10 speed Rear derailleur and am having problem shifting to the largest cog in the rear (the rear derailleur needs to go further slightly leftward to shift to the largest cog, have tried the limits of the L limit screw. Can be adjusted using the cable tension, but then the second largest cog is skipped on my first click down).

I have used 2 spacers (1 black spacer that came with the Shimano RS 100 wheel and a silver spacer that came with my Shimano 6700 ultegra cassette) before screwing the cassette on the wheel.

Is there any guide or advice to solve this please?

Andy Somnifac 

I'm still on all 10s vintage gear, so I don't know which spacers are needed were, but if it needs to come further in towards the hub, it sounds like the spacers have moved the entire cassette farther to the right. Have you checked your limit screw(s) and made appropriate adjustments?

popeye

Too many spacers.

Elvo

You need a 1.85mm spacer if using a 10 speed road 11 speed mountain cassette on a 11 speed road freehub.

aprofromindia

actually had to completely retune the rear derailleur with both the spacers (1.85 mm + 1 mm), works like a charm now

joejack951

This is the correct spacer arrangement for a Shimano 10 speed cassette used on an 11 speed hub. Glad you got it working correctly.

For those without much Shimano 10 speed experience, those cassettes require a 1mm spacer on a 8/9/10 speed hub (other than on rare Shimano 10 speed only hubs on which they fit without a spacer). So to fit an 11 speed hub, both the 1.85mm spacer and the 1mm spacer are required. SRAM 10 speed cassettes have the same spacing as Shimano but have the extra 1mm built into the cassette itself.

Psimet2001 

This is also a bit of the crappy part - later generation 10 speed Shimano cassettes do not use the 1mm spacer.

The only time you need to use a 1mm spacer the back of the cassette will have a recess or it and the spline will be the tall "10 speed only" spline that was extremely short lived. That spacer was how they made the 10 speed only spline work in a "square peg round hole" way and then allowed the same cassette to be used on a standard 8/9/10 HG freehub body.

OP - as you found out it was an adjustment that was needed on the RD - limit screw.

11 speed wheels - only thing that makes the freehub 11 is that there is 1.8mm more of spline showing. When you put that 1.8 spacer on the freehub you have changed it back into a "10 speed" freehub. Then you just need to run whatever spacer came with the cassette you have.

This stuff kind of went by the wayside but it is starting to come back hard. The HG800 cassette that Shimano is spec'ing for GRX groups is an 11 speed cassette BUT it comes with a 1.8mm spacer on the back as part of the cassette. Why? because the largest cog is large enough that the cassette can be used on older 8/9/10 hg freehub bodies and still clear the spokes. Like the 10 speed shimano mtb world.

If you work with this stuff daily it's usually super easy. If not - I apologize. It can seem confusing. I assure you it really isn't though.

joejack951

I should have recalled that the later generations ditched the spacer. Thank you for pointing that out. Do you know exactly when that happened?

Psimet2001 

Pretty sure it was when 105 went 10 speed. The only ones that had the spacer were DA and Ultegra 10 speed IIRC.