Freehub wobbles
Bruce Prickett
a bit as the wheel turns. This happens on both my road bike and my
hybrid (both with Shimano HG free-hubs). What causes this sort of wobble?
Is it a problem? It doesn't seem to cause problems, but I don't know
what the source is.
Bruce Prickett
bru...@saber.eng.sun.com
Mark Vandekamp
>Bruce Prickett
>bru...@saber.eng.sun.com
I have the same problem on my Shimano Ultegra 7-speed freehub. Or maybe I
shouldn't call it a problem since it doesn't seem to affect the performance of
my hub or wheel in any significant way. Any words of wisdom out there woould
be enlightening.
Mark Vande Kamp
me...@u.washington.edu
Mark Vandekamp
>When I spin the rear wheel on my road bike, I see the cogs wobbling
>a bit as the wheel turns. This happens on both my road bike and my
>hybrid (both with Shimano HG free-hubs). What causes this sort of wobble?
>Is it a problem? It doesn't seem to cause problems, but I don't know
>what the source is.
I have the same problem with my Shimano Ultegra 7-speed freehub. Maybe I
shouldn't call it a problem, though. It hasn't caused any problem for me
either. I am curious though. Any words of wisdom out there?
Mark Vande Kamp
me...@u.washington.edu
David A. Byars
>Bruce Prickett
>bru...@saber.eng.sun.com
Yeah, that's a good question. My MTB has a Shimano free-wheel and it
wobbles when the wheel is spinning. Why?
_______________________________________________________________________________
Dave Byars "When I poison my system,
by...@mdd.comm.mot.com I take thoughts and twist them
into shapes."
-pete shelley
_______________________________________________________________________________
William Koenig Lloyd
>bru...@saber.Eng.Sun.COM (Bruce Prickett) writes:
>
>>When I spin the rear wheel on my road bike, I see the cogs wobbling
>>a bit as the wheel turns. This happens on both my road bike and my
>>hybrid (both with Shimano HG free-hubs). What causes this sort of wobble?
>>Is it a problem? It doesn't seem to cause problems, but I don't know
>>what the source is.
>
>shouldn't call it a problem since it doesn't seem to affect the performance of
>my hub or wheel in any significant way. Any words of wisdom out there woould
>be enlightening.
Two things. First, there is a bit of play on the Ultegra freehub. You
can grab the cogs and wiggle them back and forth about 1 mm or so. I was
concerned that the bearings on my freehub might have been shot on my training
wheel when it did this, but then I checked out my race wheel (probably < 500
miles), and it felt exactly the same way. I figure it's okay. Second,
just looking at the cogs gives the appearance that they're wiggling, since
hyperglide teeth are angled in strange ways. Some are angled so the teeth
have a taper toward the larger cog, and some have a taper toward the next
smallest cog. This gives the appearance that the cog is wiggling when it
actually isn't.
Bill
Isaac Leung
|> bru...@saber.Eng.Sun.COM (Bruce Prickett) writes:
|>
|> >When I spin the rear wheel on my road bike, I see the cogs wobbling
|> >a bit as the wheel turns. This happens on both my road bike and my
|> >hybrid (both with Shimano HG free-hubs). What causes this sort of wobble?
|> >Is it a problem? It doesn't seem to cause problems, but I don't know
|> >what the source is.|>
|> >Bruce Prickett
|> >bru...@saber.eng.sun.com
|>
Suntour Winner/Winner Pro 6/7 sp.
Shimano Freewheel&Freewheel 6/7 sp.
And they ALL wobble to some degree, so I don't
worry about it.
(Except when it makes that thunking noise, which
tells me it's about to eject it's guts all over the
road...)
Isaac Leung
ile...@physics.ubc.ca
Dan B. Kasha
to ease the shifting, and it is done intentionally. I personally never really
bought that, but I have not rulled it out. I could see that as the chain is
pushed with some force against the face of the cog, the woble will help the
teeth catch on the chain. Also, compared to the depth of the cut on a hyperglide
cog, the wobble is comparable.
So, I don't have a detailed explanation, it could be just play, but from the
pharse I was told 15 years ago, I thought i would say this stuff.
Dan
William Burrow
>From: by...@mdd.comm.mot.com (David A. Byars)
>Subject: Re: Freehub wobbles
>Date: Wed, 26 May 1993 22:15:29 GMT
>In <m072mq...@exodus.Eng.Sun.COM> bru...@saber.Eng.Sun.COM (Bruce Prickett) writes:
>
>>When I spin the rear wheel on my road bike, I see the cogs wobbling
>>a bit as the wheel turns. This happens on both my road bike and my
>>hybrid (both with Shimano HG free-hubs). What causes this sort of wobble?
>>Is it a problem? It doesn't seem to cause problems, but I don't know
>>what the source is.
>
>>Bruce Prickett
>>bru...@saber.eng.sun.com
>
>
>Yeah, that's a good question. My MTB has a Shimano free-wheel and it
>wobbles when the wheel is spinning. Why?
I noticed that with all my freewheels, both Shimanos and one Suntour. It
would seem to me that some off-centeredness is not considered a big problem,
and any wobble is due to the bearing system of the freewheel. It has none..
just let the parts slide over each other. Consider the maximum load on the
bearing surfaces: next to none when rotating, because you are coasting.
When putting down power to the pedals, the freewheel is locked.
So after thinking about it awhile, I decided concentrating on setting up
parameters concerning the drivetrain to the nearest thousandth of an inch a
waste time.
Anybody from the Big S companies care to comment on their products, or
conversely, anyone who is intimate with this hardware willing to divulge the
_real_ reasons? :)
Will.
stu...@bcara231.bnr.ca
ll...@leland.Stanford.EDU (William Koenig Lloyd) writes:
> In article <1u0onh...@news.u.washington.edu>
me...@stein.u.washington.edu (Mark Vandekamp) writes:
> >bru...@saber.Eng.Sun.COM (Bruce Prickett) writes:
> >
> >>When I spin the rear wheel on my road bike, I see the cogs wobbling
> >>a bit as the wheel turns. This happens on both my road bike and my
> >>hybrid (both with Shimano HG free-hubs). What causes this sort of wobble?
> >I have the same problem on my Shimano Ultegra 7-speed freehub. Or maybe I
> Two things. First, there is a bit of play on the Ultegra freehub. You
> can grab the cogs and wiggle them back and forth about 1 mm or so. I was
> concerned that the bearings on my freehub might have been shot on my training
> wheel when it did this, but then I checked out my race wheel (probably < 500
> miles), and it felt exactly the same way. I figure it's okay. Second,
> just looking at the cogs gives the appearance that they're wiggling, since
> hyperglide teeth are angled in strange ways. Some are angled so the teeth
> have a taper toward the larger cog, and some have a taper toward the next
> smallest cog. This gives the appearance that the cog is wiggling when it
> actually isn't.
>
> Bill
>
Every Shimano Freehub I have seen does this to some degree, including my 10
year old Dura ace UNIGLIDE system. It is definitly not an illusion, the cogs
woble]
Rick
Stuart Paynter
amount of wobble become excessive? This is the scenario I witnessed,
a friend just purchased a new wheelset (Bullseye hubs, Sachs 13-32 free-
wheel, Mavic 231 rims). He was experiencing poor shifting in the low
gears and some skipping under power. Looking at the freewheel rotate,
it was "wobbling" 2-3 times more (horizontal travel) than anyone elses.
Could the wobble be the cause?
Cheers...Stuart
Bruce Prickett
> >bru...@saber.Eng.Sun.COM (Bruce Prickett) writes:
> >
> >>When I spin the rear wheel on my road bike, I see the cogs wobbling
> >>a bit as the wheel turns. This happens on both my road bike and my
> >>hybrid (both with Shimano HG free-hubs). What causes this sort of wobble?
> >>Is it a problem? It doesn't seem to cause problems, but I don't know
> >>what the source is.
> Two things. First, there is a bit of play on the Ultegra freehub. You
> can grab the cogs and wiggle them back and forth about 1 mm or so. I was
> concerned that the bearings on my freehub might have been shot on my training
> wheel when it did this, but then I checked out my race wheel (probably < 500
> miles), and it felt exactly the same way. I figure it's okay.
I see this is a common phenomenon.
> Second,
> just looking at the cogs gives the appearance that they're wiggling, since
> hyperglide teeth are angled in strange ways. Some are angled so the teeth
> have a taper toward the larger cog, and some have a taper toward the next
> smallest cog. This gives the appearance that the cog is wiggling when it
> actually isn't.
>
> Bill
Clarification: the bike is mounted in a workstand, and the cranks aren't turning.
The wheel is spinning, but the cogs are not. I haven't put a dial indicator on
them, but they are definitely wobbling as the wheel turns.
I'm still curious about this behavior.
Bruce
Mike Hackett
>In article 23...@leland.Stanford.EDU, ll...@leland.Stanford.EDU (William Koenig Lloyd) writes:
>
>Clarification: the bike is mounted in a workstand, and the cranks aren't turning.
>The wheel is spinning, but the cogs are not. I haven't put a dial indicator on
>them, but they are definitely wobbling as the wheel turns.
>
>I'm still curious about this behavior.
>
>Bruce
>
I'm not an expert, but I think this is either the bearing surfaces in the
freewheel (the ones that move with the hub) not being ground true or, as
a bike shop told me, the threads of the wheel hub (that the freewheel
screws onto) not being cut true, with respect to the axle axis. I've had
this on my cheapish bikes but figured if you spent enough money on
equipment you wouldn't have it. I guess I feel a little better now.
Another possibility is that the hub threads are cut correctly, but when
spokes and rim are added the tension distorts things out of kilter somehow.
Best way to tell would be to remove the freewheel and spin the wheel to
see of the threaded part of the hub seems not perfectly concentric and/or
perpendicular to the axis of spin.
Mike
Raul Alvarez
On Shimano Hyper-Glide, the teeth on the freewheel are all of different
sizes. It actually helps shifting a little.
--
Raul Alvarez ra...@pencom.com 212-513-7777 NeXT Mail OK
sang...@med.wcc.govt.nz
>In article <m072mq...@exodus.Eng.Sun.COM> bru...@saber.Eng.Sun.COM
>(Bruce Prickett) writes:
>> When I spin the rear wheel on my road bike, I see the cogs wobbling
>> a bit as the wheel turns. This happens on both my road bike and my
>> hybrid (both with Shimano HG free-hubs). What causes this sort of
>wobble?
Firstly, have you ever noticed it while riding?
Secondly, have you noticed that many cranksets do the same thing during
pedalling?
However, I have one freewheel that does not do it.
But, this is in combination with one particular hub.
It is apparent to me, that it is just differences in machining the threads. It
is not deliberate, as in, maybe it aids shifting, but purely related to
non-precision manufacture of a part that most people throw away when cogs are
worn.
As to variation in the front rings, this would probably be caused by imprecise
casting of the crank spider and//or imprecise machining of bottom bracket axle
taper in combination with crank arm taper.
Really, nothing to worry about. If it works, ride it!
Donald
Hans-Joachim Zierke
On 27.05.93, mhac...@vnet.IBM.COM (Mike Hackett) writes:
>a bike shop told me, the threads of the wheel hub (that the freewheel
>screws onto) not being cut true, with respect to the axle axis.
Near miss. :-) Even if they are, the wobble can't be zero. If a thread
is this precise, you can't screw anything on or off. For some practical
reasons, threads are cut a bit differently.
I've had
>this on my cheapish bikes but figured if you spent enough money on
>equipment you wouldn't have it. I guess I feel a little better now.
You won't get it with Campy freehubs. Feeling bader now? :-)
But it doesn't hurt, if it's not a sideplay, and if it doesn't exceed
"normal" wobble.
hajo
Mike Hackett
>On 27.05.93, mhac...@vnet.IBM.COM (Mike Hackett) writes:
>
>>a bike shop told me, the threads of the wheel hub (that the freewheel
>>screws onto) not being cut true, with respect to the axle axis.
>
>Near miss. :-) Even if they are, the wobble can't be zero. If a thread
>is this precise, you can't screw anything on or off. For some practical
>reasons, threads are cut a bit differently.
>
whether the freewheel screws down to a nicely machined shoulder or not as
if this is a/the cause of the wobble. Having never actually seen a hub
without a freewheel on it ( I said I wasn't an expert) I don't know.
> I've had
>>this on my cheapish bikes but figured if you spent enough money on
>>equipment you wouldn't have it. I guess I feel a little better now.
>You won't get it with Campy freehubs. Feeling bader now? :-)
I'll get over it. :-)
>
>But it doesn't hurt, if it's not a sideplay, and if it doesn't exceed
>"normal" wobble.
When I had a 7-sp freewheel put on, I had a bit of trouble with
intermittent chain clunks while on the 6th cog (13 tooth) that I traced
to interference with the 7th cog (12 tooth) as the chain was leaving the
cog over the top. This only happened while on the big ring in front.
Factors contributing to this were probably chainline, the two cogs being
very close to the same diameter, but I think the freewheel wobble
I have contributed also. Could be wrong.
>
>hajo
>
Mike
Michael Batchelder
bru...@saber.Eng.Sun.COM (Bruce Prickett) writes:
If you do have cassette hubs, this is perplexing.
A normal freeWHEEL will do this, a little to a
lot, depending on the pawl/ratchet mechanism's
quality. But if you have a cassette hub, there
should be no "precession" of the axis thru the cogs.
Check the HG lockring for sufficient tightness, I
guess. If you can move the cassette cogs along the
length of the cassette body by hand, and the lockring
is tight, try a thin spacer.
--
Michael Batchelder
m...@nomad.jpl.nasa.gov.
Robert Prevelige
I have been told that the wobble is caused by an inaccurate cut of the
threads for teh freewheel and is normal. I have yet to see a freewheel
bike without the wobble. I wouldn't worry about it.
Does anyone know differently?
Bob Prevelige
r...@sage.mit.edu
Hans-Joachim Zierke
On 28.05.93, mhac...@vnet.IBM.COM (Mike Hackett) writes:
>>But it doesn't hurt, if it's not a sideplay, and if it doesn't exceed
>>"normal" wobble.
>
>When I had a 7-sp freewheel put on, I had a bit of trouble with
>intermittent chain clunks while on the 6th cog (13 tooth) that I traced
>to interference with the 7th cog (12 tooth) as the chain was leaving the
>cog over the top. This only happened while on the big ring in front.
>Factors contributing to this were probably chainline,
Very, very probably. With a good chainline, the outermost chainwheel
couldn't have more distance to the centerline of the bike than the 13.
hajo
Daryle A. Tilroe
>The explanation given 15 years ago to me about any frewheel was that they wobble
>to ease the shifting, and it is done intentionally. I personally never really
>bought that, but I have not rulled it out. I could see that as the chain is
>pushed with some force against the face of the cog, the woble will help the
>teeth catch on the chain. Also, compared to the depth of the cut on a hyperglide
>cog, the wobble is comparable.
This is also what I have been told by the repair experts in town and
it seems to make sense. It occures on all the bikes I have owned or examined
for the effect.
--
Daryle A. Tilroe ---- Direct from sunny Edmonton, Alberta,
da...@beast.math.ualberta.ca | | at the University of Alberta,
B. Sc. (Spec. Phys./Math) \ * | on the banks of the North Saskatchewan,
B. Eng. (EE 3/4) \__| with all the usual disclaimers; my sigfile!
Arthur E. Ogus
and down when spun. Most people agree that it is not a problem. In
fact, I was told that they are designed to do that on purpose so
that your derailleur can work.
Steve Manifold
I have had freewheel wobble with Suntour, Regina and Sachs-Maillard freewheels,
and I agree it is not a problem. However, all four of my 6-speed Campagnolo
freewheels have so little wobble as to be imperceptible. They index perfectly
with Suntour Accushift levers and Superbe Pro rear derailleur in 6 speed mode.
So the argument that freewheels are designed to wobble to aid in (index)
shifting doesn't hold water, to me. I think shop mechanics made that theory up
rather than admit that the parts they sell maybe aren't manufactured to the
tightest machining tolerances (except in the case of Campy. Yes, I'm a
Campyphile). Also, cheap freewheels have been wobbling long before index
shifting came around, and I see absolutely no reason why wobble would aid
in friction shifting, imprecise as it is.
steve
--
_______________________________________________________________________________
Steve Manifold University of Texas
eza...@hermes.chpc.utexas.edu College of Engineering
task...@crovax.cem.utexas.edu Center for Electromechanics
-------------------------------------------------------------------------------
Mike Hackett
I was pretty surprised when trying to understand this problem that the
outermost chainwheel was indeed farther out than the 13 (it may even be
farther out than the 12, but I don't remember now). At first I thought
this bike was really messed up, the pair of front gears should more or
less line up with the middle of the rear gear cluster to minimize the
chain angle necessary at the extremes.
But, then I thought, MAYBE it is this way because having the chain come
over the top of the smaller gears and heading inward would cause possible
interference with the larger gear to the inside. Same problem if on the
smaller ring in front with respect to interfering with the large ring. So
they lined it up such that this would never be a problem, though at the
expense of more extreme angles (and noise) when using the inner gears in
back. This was just a guess, don't flame me if it is wrong, I'd
like to know what ideal chainline is, anyway. It's been mentioned quite
a few times here as the source of problems if wrong but I've not read
what is considered to be correct.
As my bike is set up now, I have 7 nicely quiet ratios when on the smaller
ring (a 42) and about 4 when on the larger ring. I actually like it this
way, given my locale and meager ability I almost never need to be off of
the small ring, and hence only use one shifter. If moving the rings in
closer to the center of the bike (not to imply that I can easily do this,
probably can't) compromised some of the ratios with the smaller ring I
wouldn't want to do it.
Mike
Harry Phinney
: ...I'd
: like to know what ideal chainline is, anyway. It's been mentioned quite
: a few times here as the source of problems if wrong but I've not read
: what is considered to be correct.
The majority of double chainring cranks are designed to place the center
line between the rings 43.5 mm from the bike's center line.
Harry Phinney ha...@cv.hp.com
Mike Hackett
>
>The majority of double chainring cranks are designed to place the center
>line between the rings 43.5 mm from the bike's center line.
>
measurement, so it is out a little ways. The center gear of the freewheel
is 42.5 mm from the bike center line, give or take a mm. So, would
certainly appear, given your number, that the front and rear gears
should be pretty much centered on each other, and that my original guess
about how they should be positioned was wrong.
Looking at the chainline when on the small gears front and back, I see
no possibility of interference with the large ring and probably none with
the next larger cog should I move my rings inward 4-5 mm. I should
gain another quiet ratio when on the big ring if I were to do this (and
hopefully not lose one when on the small ring). The only thing
I see stopping me from doing this (well, other than finding the part or
parts to do it) is concern for clearance between the inner ring and the
chain stay (I hope that is the correct term). Right now that stands at
7 mm, enough for the chain to slip between should it be of a mind to
sometime. Is there any convention for such a gap, or is the only real
requirement just that the ring does not rub on the chain stay?
Thanks a lot, you've all been very helpful.
Mike