Need Advice: Did my LBS sell me the wrong wheel?

[The Eye]

I needed to replace the rear wheel on my bianchi hybrid.

The old one was a 700C with a shimano 7 speed hub.

When I took the new tire home I found that it was a shimano FH-RM40-8 hub
and that there was a spacer on the inner part of the hub to adjust the fit
to my 7 speed cassette.

But I now wonder if I should have gotten a wheel with a shimano 7 speed hub
and whether I should return the wheel?

The solution of using the spacer does not allow the cassette to fully insert
on the hub and that part of the hub, seems to me, would be the best part of
the fit for full transfer of the pedal force?

Any advice or thoughts would be appreciated.

 

[Werehatrack]

On Thu, 8 Sep 2005 10:44:20 -0400, "The Eye"
<[email protected]> wrote:

>I needed to replace the rear wheel on my bianchi hybrid.
>
>The old one was a 700C with a shimano 7 speed hub.
>
>When I took the new tire home I found that it was a shimano FH-RM40-8 hub
>and that there was a spacer on the inner part of the hub to adjust the fit
>to my 7 speed cassette.
>
>But I now wonder if I should have gotten a wheel with a shimano 7 speed hub
>and whether I should return the wheel?
>
>The solution of using the spacer does not allow the cassette to fully insert
>on the hub and that part of the hub, seems to me, would be the best part of
>the fit for full transfer of the pedal force?
>
>Any advice or thoughts would be appreciated.

The 7-speed hubs have been out of production for a while. That spacer
is used to correctly position the 7-speed cassette on the 8-speed
freehub. Without it, the lockring will bottom before the cassette is
fully tightened in place. The only other issue would be if the
cassette that you're trying to install is one of the old Uniglide
units with a threaded small sprocket; if so, now is the time to
replace it.

More info here:

http://sheldonbrown.com/k7.html
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[Jasper Janssen]

On Thu, 08 Sep 2005 15:22:42 GMT, Werehatrack <[email protected]>
wrote:
>On Thu, 8 Sep 2005 10:44:20 -0400, "The Eye"
><[email protected]> wrote:

>>But I now wonder if I should have gotten a wheel with a shimano 7 speed hub
>>and whether I should return the wheel?
>>
>>The solution of using the spacer does not allow the cassette to fully insert
>>on the hub and that part of the hub, seems to me, would be the best part of
>>the fit for full transfer of the pedal force?

>The 7-speed hubs have been out of production for a while. That spacer
>is used to correctly position the 7-speed cassette on the 8-speed
>freehub. Without it, the lockring will bottom before the cassette is
>fully tightened in place. The only other issue would be if the
>cassette that you're trying to install is one of the old Uniglide
>units with a threaded small sprocket; if so, now is the time to
>replace it.

Unless the spacer is the wrong size; I've seen people variously advocating
3, 4, and 4.5 mm spacers for 7-on-8.

OP: The cassette as such is only bolted/riveted together for convenience,
not structure, so the optimal transfer of force is where the individual
sprocket (or in high end large-size sprockets, the spider of several
sprockets which *are* riveted together structurally) meets the freehub
body. If the last cog is missing just a little bit of engagement, I
wouldn't worry about it, but if it's over 2 mm or so I'd consider trying
to get a thinner spacer.


Jasper

 

[[email protected]]

If the last cog is missing just a little bit of engagemen...
i fumbled spacers for some time following inadequate advice..
a loose cassette promotes wear on the hub carrier-use castrol marine
grease from woolmort-
i have a wheels 8 to 7 spacer in drawer 3 and will measure if possible.

 

[[email protected]]

the wheels mfg spacer measures 5 mil
this assumes a practical reality, practical for wheels.
straightforward as bike parts mfgs try to standardize for commoners at
life's lower eco levels. once you move up...see recent bb photo i
digress
ONE cog width plus one normal spacer equals more or less 5 mil
once the cassette type leaves wheels area and goes to atb or upscale
cassettes then there's divergence-
the shimano atb has a built in adjustment-bumps fit in a stock spacer's
holes or ride on the surface. that's about .3mm and about what one
files of the 5 mil spacer for use as an 8 speed atb on a 9 speed deore
lx hub body. which is another stroy
but upscale cassette's ahve adjuster screws on the back and these, and
the preceding, plus the right spacer should produce a mounted cassette
only wobbleing from the gap at the hub body ridges/cassette drive teeth
producing yaw around the axle axis not the inboard outboard movement
along the axle axis lack of shim width produces.