saias

I recently changed my 9 speed 12-23 dura ace cassette with a 9 speed 12-27 cassette. It was advertised as ultegra, but who knows. The ultegra cassette came with the 1.85 spacer which I figured was for 11 speed freehub. I'm installing on an ultegra 6500 hub.
I was always under the impression that 9 speed hub on a 9/10 speed freehub does not use a spacer. But when I installed the Ultegra cassette without the spacer there was free play. That's odd I thought so I installed with the spacer. It locked down, but I could tell it was closer to the spokes than the dura ace. And when I have the low setting dialed in on the derailleur, the spokes ever so slightly skim the derailleur cage so I backed it out a bit.
I'm going to add another spacer. Do you think I should go with 1mm or another 1.85?
Adding some pictures so you can get a sense on the clearances. Note the Ultegra flange is recessed compared to the dura ace. The 1.85 spacer fits flush with the recessed space.

Andrew R Stewart 

Shifting a cog set sideways is an old thing and the limits are still the same with a cassette. How much clearance is there between the small cog and the seat stay end. This is one limit for the RH direction. Another limit in that direction is whether the small cog will remain engaged with the freehub body splines with more RH shifting. Last bit is if the lock ring will still engage it's threads. Unfortunately these issues are likely to not be published and usually found out by trying.

So my question is why not try a 1mm spacer (and/or the 1.85 spacer) and report back here so that next person will know?

Shimano places their cassette model number on the lock ring. The 13-25 CS-6500 cassette I have on my desk (in it's OEM retail packaging) has a rather different largest cog/back side/freehub body contact design, are you sure the cassette is a Shimano and/or their 6500 version? Andy

saias

Good point on the small cog/seat stay clearance. Not too concerned about the lock ring engaging with an additional spacer. It definitely has a lot more threading available than the dura ace cassette. I will give each spacer a try.
The lockring is marked Shimano CS-6500, but I suspect the cogs are something else. Not a big deal as its in good condition and shifts perfectly fine.

Bill Kapaun

I've had "spoke ticking" when using a 12-23 cassette with a "mountain" RDER on my hybrid.

70sSanO

I’m assuming in the last pic, the bottom cassette is the Dura Ace and the top pic is the new Ultegra cassette. If that is correct, the DA cassette carrier/spider extends to compensate for the largest cog that sits behind the carrier/spider.

The easiest way to set it up the same is to place both cassettes on a flat surface and see how much of a gap you have from the end of the cassette splines to the flat surface.

The largest cogs should line up pretty close to each other because they are both sitting on the cog rivets. It’s the inner gap that is the issue.

John

Edit Added: now that I’ve thought about it for more than 30 seconds, use a straight edge on the back of the cassette to determine the needed spacer width.

saias

Update
I ended up going with another 1.85 spacer. It matched the extended carrier from the DA cassette. So now I have two 1.85 spacers. One which sits in the carrier recess which makes it flush with the carrier body. The other to extend the carrier. All seems good on a quick test ride.
Still a mystery what the deal is with the recess on the spider. It does not seem typical for 9 or 10 speed cassettes.

Iride01 

Might be easier to find out some info if you'd give the specific part numbers of the cassettes and any other part involved such as the rear hub/freehub. Shimano has compatibility docs and other stuff that should give us a clue.

Though if you have it all lined up and working correctly then I suppose it's pointless.

70sSanO

You know, some 90’s Shimano freehubs had a spacer pressed onto the freehub body as a stop for a cassette.

I don’t think the FH-6500 had one, but if the freehub body had ever been replaced with another one, like a FH-M737, it would have that spacer. If it was ever removed you would need a spacer just to get back to a “normal’ cassette setup.

I only mention this because having to have over 3.5mm of spacers behind a 9 speed cassette seems odd.

John

KCT1986

OP's 1st states it is a FH-6500 and he also says he got the cass which he was told was Ultegra, which would be CS-6500. From what I've seen the only road 9 speed with the carrier is DA & Ultegra.

KCT1986

The FH-6500 did not have a spacer on the rear of the freehub body.

It also has a slightly different mounting depth in the interface between the freehub body and the hub shell. Not many bodies would fit properly with the FH-6500 shell.

KCT1986

The higher end Shimano10 speed cass. with a carrier for the larger cogs needs the spacer. Haven't seen any 9 speed Shimanos that needed a spacer.

Do you think that it's possible that the unit for the large 3 cogs could have been swapped with a 10 speed unit (maybe from CS-6600)? The cog spacing difference would be 0.4mm each, or 1.2mm total (including the built-in spacer before the smallest cog on the carrier. Possibly too small of a difference to notice or effect indexing.

70sSanO

Thanks for the info.

I do disagree with not many bodies properly fit.

Shimano had the same attach spline and the only difference was the shallow/deep freehub body flange. If you get the correct flange and use right cone and seal it shouldn’t be a problem.

I recently did a 20 year swing with a 1055 freehub body on a FH-5700.

One thing Shimano made pretty easy.

The 74XX series was the oddball back then.

John

KCT1986

In many of the Shimano hubs the swap is quite easy. The FH-1055 and the FH-5700 uses the very common interface. Like this:


The FH-6500 does not use the same common interface. It is one of the outliers and does not have very many options for swaps.

My point being, it was highly unlikely that a swap was done. Even less probable would be a freehub body with the pressed in spacer, which in itself was an outlier.

saias

It's a 6500 hub. I did not take a close look at the freehub to see if it was a replacement, but I don't think it is. It is a little discerning to have 3.7mm of spacers but it does match up well with the DA cassette. And the lockring has enough threading, and there is good clearance at the spokes and dropout.
I can't find it now, but I did come across a page that mentioned some 10 speed Shimano cassettes did have a recessed spider like mine. If that is the case, I suspect the previous owner of the Ultegra cassette used a 6600 21-24-27 spider.