[Rovernet] Rovernet Digest, Vol 143, Issue 4
Charles Kellogg
charlesk at darebritannia.com
Wed Aug 20 12:15:52 EDT 2025
Bill,
Your explanation of the speedo's inner workings is brilliant. Or maybe
"just" you are !!! LOL That was VERY enlightening indeed. THANK YOU !!!
aFTER WORKING ON lNAD-rOVERS FOR MORE THAN 55 YEARS THAT'S THE BEST
EXPLANATION i'VE EVER READ !! OOPS THE CAPS LOCK SWITCHED ON !! So do U
know what causes the innards of a speedo crash, requiring a rebuild?
Warm regards,
Charles Kellogg
Director of Restorations
Dare Britannia, Ltd.
1043 Kaiser Rd. SW, Unit C
Olympia, WA 98512, USA
http://www.darebritannia.com/
Why not leave us a 5 Star Review on Google?
Click Here
<https://www.google.com/search?q=dare+britannia&ei=3MfQYNHGHcvt-gT67JRQ&gs_ssp=eJzj4tFP1zc0MjPMszCONzVgtFI1qDA1sTQ0N002SEu1MLMwN7G0MqiwNE5NMk8EQoOUJEuzJCMvvpTEolSFpKLMksS8vMxEAGn5E3M&oq=Dare+B&gs_lcp=Cgdnd3Mtd2l6EAEYADINCC4QxwEQrwEQQxCTAjICCAAyAggAMgIIADIECAAQCjICCAAyAgguMgIIADICCAAyAgguOggILhDHARCjAjoECAAQQzoECC4QQzoLCC4QsQMQxwEQowI6CAguELEDEIMBOgUIABCxAzoKCAAQsQMQgwEQQzoHCAAQsQMQQzoFCC4QsQM6BwguELEDEEM6CAgAELEDEIMBULyGAljrkAJggZ4CaABwAngAgAGvBYgBjSOSAQM1LTeYAQCgAQGqAQdnd3Mtd2l6wAEB&sclient=gws-wiz>
*Thank you for your enquiry for our parts and services. We offer the
highest-quality spare parts for the vintage Land -Rover. Our staff is
minuscule while the demand for rare and “unobtainable” parts for early
Land-Rovers is relentless. While your concern is important to us, our
ability to respond to each and every enquiry may be limited and stocks of
many items are critically low.. We are primarily a restoration-based
enterprise but when we have a surplus of a given item, we are able to
offer excess stocks to our dedicated clients. If your need is urgent, we
encourage you to contact us by phone, in person. Leaving a message is
rarely effective, so we recommend direct contact. With many buildings full
of parts, it is not always easy to locate obscure items, and the process is
often time consuming. We hope you understand. Please
provide complete details of your exact model including year, wheelbase,
which side drive, engine, Country of origin, etc. When giving part numbers,
please also state the catalogue number (typically found on the front
cover). We appreciate your understanding and will do all we can to help.*
Voice 360-866-2254
[image: New Logo]
On Wed, Aug 20, 2025 at 9:00 AM <rovernet-request at rovernet.org> wrote:
> Send Rovernet mailing list submissions to
> rovernet at rovernet.org
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> or, via email, send a message with subject or body 'help' to
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> Please edit your digest reply by changing the subject line to the topic to
> which you are referring.
> ************************************
>
>
> Today's Topics:
>
> 1. Re: Rovernet Digest, Vol 143, Issue 3 (Charles Kellogg)
> 2. Re: speedo is nervous (magnet at ican.net)
> 3. Re: speedo is nervous (Jim Pile)
> 4. Re: speedo is nervous (Gordon Reddy)
> 5. Re: speedo is nervous (larry williamson)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 19 Aug 2025 09:04:26 -0700
> From: Charles Kellogg <charlesk at darebritannia.com>
> To: rovernet at rovernet.org
> Subject: Re: [Rovernet] Rovernet Digest, Vol 143, Issue 3
> Message-ID:
> <
> CAEuq98uCN0wsxY7z0GZquyicRLRPEJKO6Z+UE1ksSfX0xnbySA at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> I suggest checking your cable, 1st at the gearbox 2 b sure connection is
> tight, 2nd at speedo. If connections tight checking 4 cable sheath
> burned thru or rusty IWC, replace cable. If no outer cable flaws evident
> then pull inner cable and relubricate.
>
>
> Charles Kellogg
> Director of Restorations
> Dare Britannia, Ltd.
> 1043 Kaiser Rd. SW, Unit C
> Olympia, WA 98512, USA
> http://www.darebritannia.com/
>
> Why not leave us a 5 Star Review on Google?
> Click Here
> <
> https://www.google.com/search?q=dare+britannia&ei=3MfQYNHGHcvt-gT67JRQ&gs_ssp=eJzj4tFP1zc0MjPMszCONzVgtFI1qDA1sTQ0N002SEu1MLMwN7G0MqiwNE5NMk8EQoOUJEuzJCMvvpTEolSFpKLMksS8vMxEAGn5E3M&oq=Dare+B&gs_lcp=Cgdnd3Mtd2l6EAEYADINCC4QxwEQrwEQQxCTAjICCAAyAggAMgIIADIECAAQCjICCAAyAgguMgIIADICCAAyAgguOggILhDHARCjAjoECAAQQzoECC4QQzoLCC4QsQMQxwEQowI6CAguELEDEIMBOgUIABCxAzoKCAAQsQMQgwEQQzoHCAAQsQMQQzoFCC4QsQM6BwguELEDEEM6CAgAELEDEIMBULyGAljrkAJggZ4CaABwAngAgAGvBYgBjSOSAQM1LTeYAQCgAQGqAQdnd3Mtd2l6wAEB&sclient=gws-wiz
> >
>
> *Thank you for your enquiry for our parts and services. We offer the
> highest-quality spare parts for the vintage Land -Rover. Our staff is
> minuscule while the demand for rare and “unobtainable” parts for early
> Land-Rovers is relentless. While your concern is important to us, our
> ability to respond to each and every enquiry may be limited and stocks of
> many items are critically low.. We are primarily a restoration-based
> enterprise but when we have a surplus of a given item, we are able to
> offer excess stocks to our dedicated clients. If your need is urgent, we
> encourage you to contact us by phone, in person. Leaving a message is
> rarely effective, so we recommend direct contact. With many buildings full
> of parts, it is not always easy to locate obscure items, and the process is
> often time consuming. We hope you understand. Please
> provide complete details of your exact model including year, wheelbase,
> which side drive, engine, Country of origin, etc. When giving part numbers,
> please also state the catalogue number (typically found on the front
> cover). We appreciate your understanding and will do all we can to help.*
>
>
> Voice 360-866-2254
>
>
> [image: New Logo]
>
>
> On Tue, Aug 19, 2025, 9:00 AM <rovernet-request at rovernet.org> wrote:
>
> > Send Rovernet mailing list submissions to
> > rovernet at rovernet.org
> >
> > To subscribe or unsubscribe via the World Wide Web, visit
> > http://rovernet.org/mailman/listinfo/rovernet_rovernet.org
> > or, via email, send a message with subject or body 'help' to
> > rovernet-request at rovernet.org
> >
> > You can reach the person managing the list at
> > rovernet-owner at rovernet.org
> >
> > When replying, please edit your Subject line so it is more specific
> > than "Re: Contents of Rovernet digest..."
> >
> >
> > Please edit your digest reply by changing the subject line to the topic
> to
> > which you are referring.
> > ************************************
> >
> >
> > Today's Topics:
> >
> > 1. speedo is nervous (larry williamson)
> > 2. Re: speedo is nervous (Steven Dibdin)
> >
> >
> > ----------------------------------------------------------------------
> >
> > Message: 1
> > Date: Tue, 19 Aug 2025 06:31:47 -0600
> > From: larry williamson <lewill4756 at gmail.com>
> > To: Rovernet <rovernet at rovernet.org>
> > Subject: [Rovernet] speedo is nervous
> > Message-ID:
> > <
> > CAPSjzi49d4HqBeHAS0zVe8NQ63yROH6kuS6tKZ9bWhtnWP2X7Q at mail.gmail.com>
> > Content-Type: text/plain; charset="utf-8"
> >
> > My speedo is steady sometimes and sometimes jumps around. What is the
> > reason and how to fix? I can't seem to find out in the classic forum
> these
> > notes. Larry
> > -------------- next part --------------
> > An HTML attachment was scrubbed...
> > URL: <
> >
> http://rovernet.org/pipermail/rovernet_rovernet.org/attachments/20250819/b4054e3a/attachment-0001.htm
> > >
> >
> > ------------------------------
> >
> > Message: 2
> > Date: Tue, 19 Aug 2025 14:21:23 +0100
> > From: Steven Dibdin <sdibdin at gmail.com>
> > To: Rovernet <rovernet at rovernet.org>
> > Cc: larry williamson <lewill4756 at gmail.com>, Rovernet
> > <rovernet at rovernet.org>
> > Subject: Re: [Rovernet] speedo is nervous
> > Message-ID: <43FEA171-275D-49AF-AD01-F01EC598F612 at gmail.com>
> > Content-Type: text/plain; charset=utf-8
> >
> > Which model Rover do you have Larry?
> >
> > Steven
> >
> > Sent from a small screen, please excuse any typos.
> >
> > > On Aug 19, 2025, at 13:32, larry williamson via Rovernet <
> > rovernet at rovernet.org> wrote:
> > >
> > >
> > > My speedo is steady sometimes and sometimes jumps around. What is the
> > reason and how to fix? I can't seem to find out in the classic forum
> these
> > notes. Larry
> > > _______________________________________________
> > > Rovernet mailing list
> > > Rovernet at rovernet.org
> > > http://rovernet.org/mailman/listinfo/rovernet_rovernet.org
> >
> > ------------------------------
> >
> > Subject: Digest Footer
> >
> > _______________________________________________
> > Rovernet mailing list
> > Rovernet at rovernet.org
> > http://rovernet.org/mailman/listinfo/rovernet_rovernet.org
> >
> >
> > ------------------------------
> >
> > End of Rovernet Digest, Vol 143, Issue 3
> > ****************************************
> >
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> ------------------------------
>
> Message: 2
> Date: Tue, 19 Aug 2025 13:48:46 -0400
> From: "magnet at ican.net" <magnet at ican.net>
> To: larry williamson via Rovernet <rovernet at rovernet.org>
> Subject: Re: [Rovernet] speedo is nervous
> Message-ID: <e7a4c8b4-7266-420c-b65e-b6f0080ad961 at ican.net>
> Content-Type: text/plain; charset=UTF-8; format=flowed
>
> Hi Larry,
>
> Speedo issues almost always come down to lubrication, or to be more
> precise the lack of it.
>
> As has been pointed out, the lube in the cable, and if present, in the
> right-angle drive behind the speedo head, dries out and gets gummy.
> Anything that resists the even turning of the cable, especially up near
> the head, can cause jitter, as the cable "winds up" and then "lets go"
> once it overcomes the resistance. On the "let go" phase, the cable
> momentarily gives a little surge, resulting in a spike in the speedo
> reading.
>
> But a more insidious problem inside the speedo head itself often causes
> this surging, and lubricating the cable alone will not eliminate it.
> Smiths (aka British Jaeger) speedometers use a little pawl-and-ratchet
> arrangement to drive the mileage counter. A worm on the speedo input
> shaft turns a pinion gear, and this gear moves a pawl back and forth
> every time it goes around. The pawl, in turn, pushes a toothed wheel
> around a few degrees on each stroke, and this wheel is coupled to the
> tenths-of-a-mile dial of the mileage counter.
>
> Now what happens when the lubricant of the pawl and the toothed wheel it
> drives dries out?
>
> The wheel gets harder for the pawl to turn. The pawl thus has to work
> harder on the forward stroke as it turns the wheel. This causes a
> heavier load on the speedo cable, which winds up a bit. But the pawl's
> return stroke is easier, and the cable unwinds, giving a flip to the
> speedo needle. Depending on your speed, this oscillation takes place a
> couple of times each second or faster, resulting in a small but
> noticeable jitter in the speedo needle. At some speed, this jitter
> coincides with the resonant frequency of the needle and hairspring
> assembly and you get a really big swing on the needle.
>
> But wait, it gets even more interesting! Every time the tenths dial
> goes through a revolution, it moves the mile wheel forward by 1. So the
> pawl has to work even harder to turn two dials, wnding up the cable even
> more, and causing a bigger flip when it relaxes. So once every mile,
> you'll get a bigger swing of the needle. And every ten miles, an even
> bigger swing, etc.
>
> Lubricating the pawl is easy, once you have opened up the speedo head,
> and greasing the pinion wheel shaft is pretty straightforward too. In
> my case, binding of this shaft was the main culprit. Just as well, as
> lubrication of the six-wheel dial assembly would have involved more
> disassembly than I was prepared to undertake.
>
> Cheers,
>
> -- Bill Daddis
>
>
> On 19-Aug-2025 8:31 a.m., larry williamson via Rovernet wrote:
> > My speedo is steady sometimes and sometimes jumps around. What is the
> > reason and how to fix? I can't seem to find out in the classic forum
> > these notes. Larry
> >
> > _______________________________________________
> > Rovernet mailing list
> > Rovernet at rovernet.org
> > http://rovernet.org/mailman/listinfo/rovernet_rovernet.org
>
> ------------------------------
>
> Message: 3
> Date: Tue, 19 Aug 2025 18:02:15 +0000 (UTC)
> From: Jim Pile <jpile1 at verizon.net>
> To: Rovernet <rovernet at rovernet.org>
> Subject: Re: [Rovernet] speedo is nervous
> Message-ID: <293331860.863655.1755626535318 at mail.yahoo.com>
> Content-Type: text/plain; charset="utf-8"
>
> Amazingly detailed info, Bill. Thanks for explaining a ubiquitous issue
> with the earlier P6 models.
>
>
> Sent from the all new AOL app for iOS
>
>
> On Tuesday, August 19, 2025, 1:49 PM, magnet--- via Rovernet <
> rovernet at rovernet.org> wrote:
>
> Hi Larry,
>
> Speedo issues almost always come down to lubrication, or to be more
> precise the lack of it.
>
> As has been pointed out, the lube in the cable, and if present, in the
> right-angle drive behind the speedo head, dries out and gets gummy.
> Anything that resists the even turning of the cable, especially up near
> the head, can cause jitter, as the cable "winds up" and then "lets go"
> once it overcomes the resistance. On the "let go" phase, the cable
> momentarily gives a little surge, resulting in a spike in the speedo
> reading.
>
> But a more insidious problem inside the speedo head itself often causes
> this surging, and lubricating the cable alone will not eliminate it.
> Smiths (aka British Jaeger) speedometers use a little pawl-and-ratchet
> arrangement to drive the mileage counter. A worm on the speedo input
> shaft turns a pinion gear, and this gear moves a pawl back and forth
> every time it goes around. The pawl, in turn, pushes a toothed wheel
> around a few degrees on each stroke, and this wheel is coupled to the
> tenths-of-a-mile dial of the mileage counter.
>
> Now what happens when the lubricant of the pawl and the toothed wheel it
> drives dries out?
>
> The wheel gets harder for the pawl to turn. The pawl thus has to work
> harder on the forward stroke as it turns the wheel. This causes a
> heavier load on the speedo cable, which winds up a bit. But the pawl's
> return stroke is easier, and the cable unwinds, giving a flip to the
> speedo needle. Depending on your speed, this oscillation takes place a
> couple of times each second or faster, resulting in a small but
> noticeable jitter in the speedo needle. At some speed, this jitter
> coincides with the resonant frequency of the needle and hairspring
> assembly and you get a really big swing on the needle.
>
> But wait, it gets even more interesting! Every time the tenths dial
> goes through a revolution, it moves the mile wheel forward by 1. So the
> pawl has to work even harder to turn two dials, wnding up the cable even
> more, and causing a bigger flip when it relaxes. So once every mile,
> you'll get a bigger swing of the needle. And every ten miles, an even
> bigger swing, etc.
>
> Lubricating the pawl is easy, once you have opened up the speedo head,
> and greasing the pinion wheel shaft is pretty straightforward too. In
> my case, binding of this shaft was the main culprit. Just as well, as
> lubrication of the six-wheel dial assembly would have involved more
> disassembly than I was prepared to undertake.
>
> Cheers,
>
> -- Bill Daddis
>
>
> On 19-Aug-2025 8:31 a.m., larry williamson via Rovernet wrote:
> > My speedo is steady sometimes and sometimes jumps around. What is the
> > reason and how to fix? I can't seem to find out in the classic forum
> > these notes. Larry
> >
> > _______________________________________________
> > Rovernet mailing list
> > Rovernet at rovernet.org
> > http://rovernet.org/mailman/listinfo/rovernet_rovernet.org
>
> _______________________________________________
> Rovernet mailing list
> Rovernet at rovernet.org
> http://rovernet.org/mailman/listinfo/rovernet_rovernet.org
>
>
>
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> >
>
> ------------------------------
>
> Message: 4
> Date: Tue, 19 Aug 2025 20:11:24 -0700
> From: Gordon Reddy <gorgowof at gmail.com>
> To: Rovernet <rovernet at rovernet.org>
> Subject: Re: [Rovernet] speedo is nervous
> Message-ID:
> <CAGxhdkEjvR_Gaix=mNoYh0kNte+ZtZXbU8V=
> JPjjdECeL4wgow at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Amazing! I will try this on my P5 this winter, thank you Bill!
> Gord Reddy
>
> On Tue, 19 Aug 2025 at 11:03, Jim Pile via Rovernet <rovernet at rovernet.org
> >
> wrote:
>
> > Amazingly detailed info, Bill. Thanks for explaining a ubiquitous issue
> > with the earlier P6 models.
> >
> >
> > Sent from the all new AOL app for iOS
> > <
> https://aolapp.onelink.me/eG2g?pid=NativePlacement&c=US_Acquisition_YMktg_320_EmailSignature_AttributionDL&af_sub1=Acquisition&af_sub2=US_YMktg&af_sub3=&af_sub4=100002473&af_sub5=SentFromNewAOLApp__Interstitial_&af_ios_store_cpp=ce85ce34-ad0f-4811-a92b-a172743b064e&af_android_url=https%3A%2F%2Fplay.google.com%2Fstore%2Fapps%2Fdetails%3Fid%3Dcom.aol.mobile.aolapp%26listing%3Demail_signature_attribution
> >
> >
> > On Tuesday, August 19, 2025, 1:49 PM, magnet--- via Rovernet <
> > rovernet at rovernet.org> wrote:
> >
> > Hi Larry,
> >
> > Speedo issues almost always come down to lubrication, or to be more
> > precise the lack of it.
> >
> > As has been pointed out, the lube in the cable, and if present, in the
> > right-angle drive behind the speedo head, dries out and gets gummy.
> > Anything that resists the even turning of the cable, especially up near
> > the head, can cause jitter, as the cable "winds up" and then "lets go"
> > once it overcomes the resistance. On the "let go" phase, the cable
> > momentarily gives a little surge, resulting in a spike in the speedo
> > reading.
> >
> > But a more insidious problem inside the speedo head itself often causes
> > this surging, and lubricating the cable alone will not eliminate it.
> > Smiths (aka British Jaeger) speedometers use a little pawl-and-ratchet
> > arrangement to drive the mileage counter. A worm on the speedo input
> > shaft turns a pinion gear, and this gear moves a pawl back and forth
> > every time it goes around. The pawl, in turn, pushes a toothed wheel
> > around a few degrees on each stroke, and this wheel is coupled to the
> > tenths-of-a-mile dial of the mileage counter.
> >
> > Now what happens when the lubricant of the pawl and the toothed wheel it
> > drives dries out?
> >
> > The wheel gets harder for the pawl to turn. The pawl thus has to work
> > harder on the forward stroke as it turns the wheel. This causes a
> > heavier load on the speedo cable, which winds up a bit. But the pawl's
> > return stroke is easier, and the cable unwinds, giving a flip to the
> > speedo needle. Depending on your speed, this oscillation takes place a
> > couple of times each second or faster, resulting in a small but
> > noticeable jitter in the speedo needle. At some speed, this jitter
> > coincides with the resonant frequency of the needle and hairspring
> > assembly and you get a really big swing on the needle.
> >
> > But wait, it gets even more interesting! Every time the tenths dial
> > goes through a revolution, it moves the mile wheel forward by 1. So the
> > pawl has to work even harder to turn two dials, wnding up the cable even
> > more, and causing a bigger flip when it relaxes. So once every mile,
> > you'll get a bigger swing of the needle. And every ten miles, an even
> > bigger swing, etc.
> >
> > Lubricating the pawl is easy, once you have opened up the speedo head,
> > and greasing the pinion wheel shaft is pretty straightforward too. In
> > my case, binding of this shaft was the main culprit. Just as well, as
> > lubrication of the six-wheel dial assembly would have involved more
> > disassembly than I was prepared to undertake.
> >
> > Cheers,
> >
> > -- Bill Daddis
> >
> >
> > On 19-Aug-2025 8:31 a.m., larry williamson via Rovernet wrote:
> > > My speedo is steady sometimes and sometimes jumps around. What is the
> > > reason and how to fix? I can't seem to find out in the classic forum
> > > these notes. Larry
> > >
> > > _______________________________________________
> > > Rovernet mailing list
> > > Rovernet at rovernet.org
> > > http://rovernet.org/mailman/listinfo/rovernet_rovernet.org
> >
> > _______________________________________________
> > Rovernet mailing list
> > Rovernet at rovernet.org
> > http://rovernet.org/mailman/listinfo/rovernet_rovernet.org
> >
> > _______________________________________________
> > Rovernet mailing list
> > Rovernet at rovernet.org
> > http://rovernet.org/mailman/listinfo/rovernet_rovernet.org
> >
> -------------- next part --------------
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> >
>
> ------------------------------
>
> Message: 5
> Date: Wed, 20 Aug 2025 05:22:46 -0600
> From: larry williamson <lewill4756 at gmail.com>
> To: Rovernet <rovernet at rovernet.org>
> Subject: Re: [Rovernet] speedo is nervous
> Message-ID:
> <CAPSjzi5Q6=eXv8gUNP3L5oSd4OxJsL378x7KES0eGxbKzVa=
> Jw at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Thank for all that responded. Now the work begins. Larry
>
> On Tue, Aug 19, 2025 at 9:12 PM Gordon Reddy via Rovernet <
> rovernet at rovernet.org> wrote:
>
> > Amazing! I will try this on my P5 this winter, thank you Bill!
> > Gord Reddy
> >
> > On Tue, 19 Aug 2025 at 11:03, Jim Pile via Rovernet <
> rovernet at rovernet.org>
> > wrote:
> >
> >> Amazingly detailed info, Bill. Thanks for explaining a ubiquitous issue
> >> with the earlier P6 models.
> >>
> >>
> >> Sent from the all new AOL app for iOS
> >> <
> https://aolapp.onelink.me/eG2g?pid=NativePlacement&c=US_Acquisition_YMktg_320_EmailSignature_AttributionDL&af_sub1=Acquisition&af_sub2=US_YMktg&af_sub3=&af_sub4=100002473&af_sub5=SentFromNewAOLApp__Interstitial_&af_ios_store_cpp=ce85ce34-ad0f-4811-a92b-a172743b064e&af_android_url=https%3A%2F%2Fplay.google.com%2Fstore%2Fapps%2Fdetails%3Fid%3Dcom.aol.mobile.aolapp%26listing%3Demail_signature_attribution
> >
> >>
> >> On Tuesday, August 19, 2025, 1:49 PM, magnet--- via Rovernet <
> >> rovernet at rovernet.org> wrote:
> >>
> >> Hi Larry,
> >>
> >> Speedo issues almost always come down to lubrication, or to be more
> >> precise the lack of it.
> >>
> >> As has been pointed out, the lube in the cable, and if present, in the
> >> right-angle drive behind the speedo head, dries out and gets gummy.
> >> Anything that resists the even turning of the cable, especially up near
> >> the head, can cause jitter, as the cable "winds up" and then "lets go"
> >> once it overcomes the resistance. On the "let go" phase, the cable
> >> momentarily gives a little surge, resulting in a spike in the speedo
> >> reading.
> >>
> >> But a more insidious problem inside the speedo head itself often causes
> >> this surging, and lubricating the cable alone will not eliminate it.
> >> Smiths (aka British Jaeger) speedometers use a little pawl-and-ratchet
> >> arrangement to drive the mileage counter. A worm on the speedo input
> >> shaft turns a pinion gear, and this gear moves a pawl back and forth
> >> every time it goes around. The pawl, in turn, pushes a toothed wheel
> >> around a few degrees on each stroke, and this wheel is coupled to the
> >> tenths-of-a-mile dial of the mileage counter.
> >>
> >> Now what happens when the lubricant of the pawl and the toothed wheel it
> >> drives dries out?
> >>
> >> The wheel gets harder for the pawl to turn. The pawl thus has to work
> >> harder on the forward stroke as it turns the wheel. This causes a
> >> heavier load on the speedo cable, which winds up a bit. But the pawl's
> >> return stroke is easier, and the cable unwinds, giving a flip to the
> >> speedo needle. Depending on your speed, this oscillation takes place a
> >> couple of times each second or faster, resulting in a small but
> >> noticeable jitter in the speedo needle. At some speed, this jitter
> >> coincides with the resonant frequency of the needle and hairspring
> >> assembly and you get a really big swing on the needle.
> >>
> >> But wait, it gets even more interesting! Every time the tenths dial
> >> goes through a revolution, it moves the mile wheel forward by 1. So the
> >> pawl has to work even harder to turn two dials, wnding up the cable even
> >> more, and causing a bigger flip when it relaxes. So once every mile,
> >> you'll get a bigger swing of the needle. And every ten miles, an even
> >> bigger swing, etc.
> >>
> >> Lubricating the pawl is easy, once you have opened up the speedo head,
> >> and greasing the pinion wheel shaft is pretty straightforward too. In
> >> my case, binding of this shaft was the main culprit. Just as well, as
> >> lubrication of the six-wheel dial assembly would have involved more
> >> disassembly than I was prepared to undertake.
> >>
> >> Cheers,
> >>
> >> -- Bill Daddis
> >>
> >>
> >> On 19-Aug-2025 8:31 a.m., larry williamson via Rovernet wrote:
> >> > My speedo is steady sometimes and sometimes jumps around. What is the
> >> > reason and how to fix? I can't seem to find out in the classic forum
> >> > these notes. Larry
> >> >
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