tjc4golf

I have an older bike with a 7 speed Shimano 105 groupset that is in need of a new rear wheel. Based on the following from Sheldon Brown, I figured I’d be fine with a 8/9/10 130mm hub and 4.5mm spacer:
Also, hubs marked "8-speed", "9-speed" or "10-speed" will work with any number of sprockets! (Add a 4.5 mm spacer before installing a 7-speed cassette on an 8-, 9-, or 10-speed hub., and the included 1-mm spacer before installing a 10-speed cassettes on an 8- or 9- speed hub.)

So I bought a new rear wheel with a 8/9/10 speed, 130mm Shimano 105 hub. I also bought a 4.5mm spacer.

Now I’m trying to install the old cassette on the new hub using the 4.5mm spacer and having problems. First I drop the 4.5mm spacer on the hub. Next I install the cluster with the six cogs followed by the spacer (not the 4.5mm spacer but the spacer that is part of the cassette) and finally the seventh cog. The problem is that while the first six cogs and the spacer are held in place by the hub’s splines, the seventh cog sits just outside the splines and rotates freely.

Not sure if I’m doing something wrong or if I got the wrong spacer. I’m guessing I’m doing something wrong but I found this thread in which someone else reports that a 4.5mm spacer was too big (see post #17) which makes me wonder. Any thoughts?

Also, I’ve noticed that if I put the 4.5mm spacer on the hub between the cassette and the lockring everything fits and I don’t run into the problem of the 7th cog spinning freely. I am however hesitant to try this as Sheldon says to install the 4.5mm spacer before. Any thoughts on the suitability of this fix?

mechBgon

If it were me, I'd just find a mix of spacers that gets the job done in the inboard position. I think there's a benefit to having the spacers at the inboard end: if you happen to want to use an 11-tooth cog at some point, having the spacer at the outboard end won't work because 11t cogs are like a "cap," they cannot slide onto the hub further than a certain distance.

wrk101

Make sure you have all the cogs seated fully. The final (small) cog sometimes does not want to seat all the way, so it will not tighten down properly. Rotate it around and remount it until it fully seats. But I think this is more likely: Does the spacer have cutouts for the rivets on the backside of the cassette? If so, make sure you have the spacer in the right position. That would be my guess.

tjc4golf

Thanks for all the replies thus far...

Could you elaborate on the benefit (necessity?) of having the spacer on the inside. I follow the 11t cog thing but I'm only running 13t. I haven't tried it yet but presuming the range of the rear derailleur is sufficient, what is the downside to having the spacer on the outside.

Thanks for the input. I've tried all this and the problem persists.

HillRider

Two possible problems:

1. Many Shimano cassettes have most of the larger cogs held together with bolts or rivets and the heads of these can protrude from behind the largest cog. These bolts or rivets heads will prevent the 4.5 mm spacer from seating flush with the back of the cassette and hold it too far out. Solution: remove the bolts or position the spacer between the smallest cog and the lockring. As noted putting the 4.5 mm spacer outboard won't work with an 11T cog but will with a 12 or 13T.

2. Most Shimano cassettes have the spacer for the smallest cog built into the cog and a separate spacer between it and the nexr smallest cog isn't needed. If there is a spacer of noticable thickness in there maybe it doesn't belong.

tjc4golf

Thanks, HillRider!

I think #1 is the problem I'm facing. There are three bolts on the outside of the largest cog. Without the spacer these bolts fit in the hub's splines so they don't add any space. With the spacer however they don't fit in the splines and thus the addition of the spacer adds more than 4.5mm... approximately 5.5mm.

Putting the 4.5mm spacer outside is easier than grinding the bolts off the cassette. I like easy so this is the route I'll go unless there are any advantages to putting the spacer on the inside. Thoughts regarding the advantages/disavantages of the two positions.

mechBgon

Or just remove the bolts with an adjustable wrench or pliers. They're not necessary, and are simple to remove.

HillRider

The bolts usually have a small hex head (4mm) or take a 2mm mm allen key to remove so they aren't difficult to take out. Then, of course, you have a full set of loose cogs to deal with but that's no real problem.

There is no benefit in my experience form either installation position and I've done it both ways. Be sure to check your limit screw settings no matter what you do.

joejack951

If the protruding bolts are the problem, cut notches into the spacer for the bolts to sit in. Should take a few minutes with a Dremel or a couple more with a file.

tjc4golf

Once again, thanks for all the helpful responses!

Didn’t realize those bolts on the back of the cassette unscrewed. Since Sheldon said to put the spacer on first, I removed the bolts put the spacer on and then the cassette.

I took the bike for a test ride this morning and noticed some noise (a little rattling… sounds like something is loose) coming from the back wheel on bumpy terrain (I ride in an urban environment where I encounter cobblestones, bricks, concrete pavers, uneven and patched roads, manhole covers, potholes, etc). With the removal of the bolts, could the cassette be rattling slightly? Or maybe something else is loose? Mechanically I think its fine as is. Shifts perfectly and nothing feels loose… just the sound. That said, I prefer the quieter ride I enjoyed before. If the consensus is that it is the lack of bolts causing the noise, I’ll add the bolts and move the spacer to the outside or keep the spacer inside and grind grooves in the spacer for the bolts as joejack951 suggests.

I don’t think this is causing the sound but in the interest of full disclosure I also changed the chain last night. The old chain had 54 links. Using the calculation method and using the largest cog / largest chainring plus two links method I arrived at 55 links. I’d never had problems before with 54 but decided to go with 55 as I figured it’d be easier to shorten the chain than lengthen the chain if a change was needed. Could a looser chain result in more noise?

mechBgon

Try rotating the cogs relative to their neighbors. If you can get motion, and the cassette lockring itself is tight, then your cassette's not under compression and you'll want to add another thin spacer to resolve that for the long term.