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Old 02-23-10, 06:59 PM   #1
Raleigh71
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Do I need a spacer under my freehub?

My bike had a spoke protector in the final stages of disintegration, and I simply removed it.

I notice that when the chain is on the middle chainring and the middle gear of the freehub, it's not exactly a straight line. It's in toed a little towards the rear. It would be a straight line if I had it on the next smaller gear.

The gear changing is a little iffy at the extremes of small/large cog combinations if you get my drift.

By removing the hub protector, did I throw off the geometry and should I put a spacer under the freehub?

I never thought of spoke protectors as having any actual mechanical function as a spacer.

Any opinions?
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Old 02-23-10, 07:15 PM   #2
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Originally Posted by Raleigh71 View Post
My bike had a spoke protector in the final stages of disintegration, and I simply removed it.

I notice that when the chain is on the middle chainring and the middle gear of the freehub, it's not exactly a straight line. It's in toed a little towards the rear. It would be a straight line if I had it on the next smaller gear.

The gear changing is a little iffy at the extremes of small/large cog combinations if you get my drift.

By removing the hub protector, did I throw off the geometry and should I put a spacer under the freehub?

I never thought of spoke protectors as having any actual mechanical function as a spacer.

Any opinions?
You just need to retune your derailer, very simple a turn of a barrel adjuster will probably do.
http://www.parktool.com/repair/readhowto.asp?id=64
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Old 02-23-10, 07:16 PM   #3
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Should be no big deal.

But if you want to address it properly, the best way would be to shift the whole hub to the right by the thickness of the spoke protector, or more if there's room while you're at it, by changing washers/spacers/locknuts or whatever on the spindle and re-dishing (prolly just a matter of tightening the NDS spokes by 1/8 or 1/4 turn).
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Old 02-23-10, 09:42 PM   #4
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Originally Posted by cnnrmccloskey View Post
You just need to retune your derailer, very simple a turn of a barrel adjuster will probably do.
http://www.parktool.com/repair/readhowto.asp?id=64
If the OP did in fact had a spoke protector which spaced the cassette out that is. If he did he'll need more than just a barrel adjuster as the entire cassette will have shifted more towards spoke side - which means limit screws are out of adjustment (assuming they were properly adjusted to begin with).
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Old 02-23-10, 09:44 PM   #5
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Should be no big deal.

But if you want to address it properly, the best way would be to shift the whole hub to the right by the thickness of the spoke protector, or more if there's room while you're at it, by changing washers/spacers/locknuts or whatever on the spindle and re-dishing (prolly just a matter of tightening the NDS spokes by 1/8 or 1/4 turn).
The thickness of a spoke protector, again if it is the kind that space the cassette out is about 1mm. There is no need to respace or redish.

OP: Please tell us what kind of dork disk you had on your bike.
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Old 02-23-10, 11:57 PM   #6
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There'd be a need to re-dish if the OP found room to move the hub over by 2mm or more.

Which wouldn't be a bad thing at all if the opportunity is there, I'm sure you'll agree.
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Old 02-24-10, 12:01 AM   #7
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There'd be a need to re-dish if the OP found room to move the hub over by 2mm or more.

Which wouldn't be a bad thing at all if the opportunity is there, I'm sure you'll agree.
But the thing is the cassette has moved, an extremely minor amount. It also does not effect hub spacing or wheel dish.
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Old 02-24-10, 12:22 AM   #8
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Cassette? If it's a cassette, it hasn't moved.

It increases the gap between the freewheel and the dropout some; perhaps allowing the chance of reducing dish, no?
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Old 02-24-10, 12:26 AM   #9
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There are currently very few spoke protectors being used as a spacer (I do not know of any being used currently on either freewheel or cassette). Way back in the day a few had metal spoke protectors that slide over the threads on a hub and then the freewheel was threaded on. If your spoke protector is plastic and attached to the spokes then it isn't used as a spacer. Depending on how many gears on the cassette -- the middle cog will/will not be aligned with the middle chain ring. Your poor shifting may be caused by many other reasons.
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Old 02-24-10, 12:36 AM   #10
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I've seen plastic dork disks that were spacers... not done for quite a while though.

I suspect it's just a matter of the same part fitting freewheel or cassette hubs.
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Old 02-24-10, 12:17 PM   #11
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If your protector was one of the rare ones that actually fit onto the freehub or just in behind the freewheel and did actually holds the cog set out a little then you'll need to adjust both the derrailleur limit screws and the indexing of the shifter to get things back to ideal. The shifter and derrailleur don't know that the cogs are not where they think they are so first adjust the barrel adjusters so the middle gears all shift well. Then move the derrailleur to the inner and outer limits and adjust the limit screws so you get clean shifts but can't overshift and potentially drop the chain off the cogs. This is particularly important with the big inner cog since without a spoke protector if by some chance the chain should drop into the gap when you're crunching up a big hill the pressure can tear up a lot of spokes to the point that the wheel can even collapse.

But the chain line being out a little due to this isn't critical at all. It just is what it is.
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Old 02-25-10, 01:48 PM   #12
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Thanks for all the info, gents and ladies!

The spoke protector was an all-plastic jobbie on a late 1990's $475 low-end bike.

It's possible that it wasn't a spacer but the components are just poorly matched on this P.O.S. Taiwan-made Schwinn.

I've spent oodles of time trying to get the chain to shift smoothly but no matter what I do it has troubles with the largest and smallest gears of the freehub.

If it shifts well onto the largest cog, I can't get the smallest cog. And vice versa. The rear derailleur is simply at its limits of travel, and this is with the stop screws removed.

It's a 7 speed freehub. If I got, say, a (cheap, used) 10 speed rear derailleur, would it give me a little more derailleur cage travel and allow me the full use of all 7 gears?
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Old 02-25-10, 02:58 PM   #13
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Your chainline is an issue, and it seems the dork disk is not a factor at all. Before you fiddle any further with the RD, I'd look at the placement of the chain at middle chainring/middle cog position. You seem to be saying that the chain moves over toward the spokes from the chainring instead of being a dead straight shot to the middle cog. THAT should first be addressed. Assuming theres room for it to move, I'd think you could take off the freehub and add a spacer to move it to the right until your chainline is right, then you can go back to setting the RD limits and fine tuning. hows the space between the smallest cog and the dropout look?
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Old 02-25-10, 08:19 PM   #14
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If the derrailleur won't shift cleaning to the two extremes and this is with the limit screws right out then it's not the derrailleur but instead the front shifter. It isn't pulling quite enough cable for some reason.

But there may be a cheezy fix for this. Most shifter tiggers or twist grips will let you press the lever and get a little more pull at the end but it won't hold it there. But often if you push the lever or twist the grip and hold it for a moment the little bit extra is enough to shift up to the big cog. From there you can let it go and it'll stay on the big cog. So the trick is to get it so it shifts properly in all the lower gears including the smallest and then see if you can catch the big cog by holding pressure or torque on the shifter as described. If it works replace the limit screws to ensure you don't carry on over into the spokes if the big cog can be even slightly over shifted with this trick.
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