<div dir="ltr"><div>Bill,</div><div><br></div><div>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? </div><div><br></div><div>Warm regards,</div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div><div dir="ltr"><br></div><div dir="ltr">Charles Kellogg</div><div dir="ltr">Director of Restorations<br><div>Dare Britannia, Ltd.</div><div>1043 Kaiser Rd. SW, Unit C</div><div>Olympia, WA 98512, USA</div></div></div><div dir="ltr"><div><div><a href="http://www.darebritannia.com/" target="_blank">http://www.darebritannia.com/</a></div><div><br></div><div><span style="font-size:14pt;font-family:Arial,sans-serif;color:rgb(31,73,125)">Why not leave us a 5 Star Review on </span><span style="font-size:14pt;font-family:Arial,sans-serif;color:rgb(0,112,192)">G</span><span style="font-size:14pt;font-family:Arial,sans-serif;color:red">o</span><span style="font-size:14pt;font-family:Arial,sans-serif;color:yellow">o</span><span style="font-size:14pt;font-family:Arial,sans-serif;color:rgb(0,112,192)">g</span><span style="font-size:14pt;font-family:Arial,sans-serif;color:rgb(0,176,80)">l</span><span style="font-size:14pt;font-family:Arial,sans-serif;color:red">e</span><span style="font-size:14pt;font-family:Arial,sans-serif;color:rgb(31,73,125)">? </span></div><div><a href="https://www.google.com/search?q=dare+britannia&ei=3MfQYNHGHcvt-gT67JRQ&gs_ssp=eJzj4tFP1zc0MjPMszCONzVgtFI1qDA1sTQ0N002SEu1MLMwN7G0MqiwNE5NMk8EQoOUJEuzJCMvvpTEolSFpKLMksS8vMxEAGn5E3M&oq=Dare+B&gs_lcp=Cgdnd3Mtd2l6EAEYADINCC4QxwEQrwEQQxCTAjICCAAyAggAMgIIADIECAAQCjICCAAyAgguMgIIADICCAAyAgguOggILhDHARCjAjoECAAQQzoECC4QQzoLCC4QsQMQxwEQowI6CAguELEDEIMBOgUIABCxAzoKCAAQsQMQgwEQQzoHCAAQsQMQQzoFCC4QsQM6BwguELEDEEM6CAgAELEDEIMBULyGAljrkAJggZ4CaABwAngAgAGvBYgBjSOSAQM1LTeYAQCgAQGqAQdnd3Mtd2l6wAEB&sclient=gws-wiz" target="_blank">Click Here</a></div><div><br></div><div><p class="MsoNormal"><i><span style="font-family:"Times New Roman",serif">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 \u201cunobtainable\u201d 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 </span><b style="font-family:"Times New Roman",serif">complete </b><span style="font-family:"Times New Roman",serif">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.</span></i><font face="Times New Roman, serif"><i> </i><span></span></font></p><p class="MsoNormal"><font face="Times New Roman, serif"><br></font></p></div><div>Voice 360-866-2254</div><div><br></div></div><div><br></div><div><img src="http://darebritanniarestorations.files.wordpress.com/2013/09/dare-britannia-logo.jpg?w=625" alt="New Logo" width="420" height="235"><br><br></div>
</div></div></div></div></div></div></div></div></div></div></div><br></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Wed, Aug 20, 2025 at 9:00\u202fAM <<a href="mailto:rovernet-request@rovernet.org">rovernet-request@rovernet.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Send Rovernet mailing list submissions to<br>
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<br>
<br>
Today's Topics:<br>
<br>
1. Re: Rovernet Digest, Vol 143, Issue 3 (Charles Kellogg)<br>
2. Re: speedo is nervous (<a href="mailto:magnet@ican.net" target="_blank">magnet@ican.net</a>)<br>
3. Re: speedo is nervous (Jim Pile)<br>
4. Re: speedo is nervous (Gordon Reddy)<br>
5. Re: speedo is nervous (larry williamson)<br>
<br>
<br>
----------------------------------------------------------------------<br>
<br>
Message: 1<br>
Date: Tue, 19 Aug 2025 09:04:26 -0700<br>
From: Charles Kellogg <<a href="mailto:charlesk@darebritannia.com" target="_blank">charlesk@darebritannia.com</a>><br>
To: <a href="mailto:rovernet@rovernet.org" target="_blank">rovernet@rovernet.org</a><br>
Subject: Re: [Rovernet] Rovernet Digest, Vol 143, Issue 3<br>
Message-ID:<br>
<<a href="mailto:CAEuq98uCN0wsxY7z0GZquyicRLRPEJKO6Z%2BUE1ksSfX0xnbySA@mail.gmail.com" target="_blank">CAEuq98uCN0wsxY7z0GZquyicRLRPEJKO6Z+UE1ksSfX0xnbySA@mail.gmail.com</a>><br>
Content-Type: text/plain; charset="utf-8"<br>
<br>
I suggest checking your cable, 1st at the gearbox 2 b sure connection is<br>
tight, 2nd at speedo. If connections tight checking 4 cable sheath<br>
burned thru or rusty IWC, replace cable. If no outer cable flaws evident<br>
then pull inner cable and relubricate.<br>
<br>
<br>
Charles Kellogg<br>
Director of Restorations<br>
Dare Britannia, Ltd.<br>
1043 Kaiser Rd. SW, Unit C<br>
Olympia, WA 98512, USA<br>
<a href="http://www.darebritannia.com/" rel="noreferrer" target="_blank">http://www.darebritannia.com/</a><br>
<br>
Why not leave us a 5 Star Review on Google?<br>
Click Here<br>
<<a href="https://www.google.com/search?q=dare+britannia&ei=3MfQYNHGHcvt-gT67JRQ&gs_ssp=eJzj4tFP1zc0MjPMszCONzVgtFI1qDA1sTQ0N002SEu1MLMwN7G0MqiwNE5NMk8EQoOUJEuzJCMvvpTEolSFpKLMksS8vMxEAGn5E3M&oq=Dare+B&gs_lcp=Cgdnd3Mtd2l6EAEYADINCC4QxwEQrwEQQxCTAjICCAAyAggAMgIIADIECAAQCjICCAAyAgguMgIIADICCAAyAgguOggILhDHARCjAjoECAAQQzoECC4QQzoLCC4QsQMQxwEQowI6CAguELEDEIMBOgUIABCxAzoKCAAQsQMQgwEQQzoHCAAQsQMQQzoFCC4QsQM6BwguELEDEEM6CAgAELEDEIMBULyGAljrkAJggZ4CaABwAngAgAGvBYgBjSOSAQM1LTeYAQCgAQGqAQdnd3Mtd2l6wAEB&sclient=gws-wiz" rel="noreferrer" target="_blank">https://www.google.com/search?q=dare+britannia&ei=3MfQYNHGHcvt-gT67JRQ&gs_ssp=eJzj4tFP1zc0MjPMszCONzVgtFI1qDA1sTQ0N002SEu1MLMwN7G0MqiwNE5NMk8EQoOUJEuzJCMvvpTEolSFpKLMksS8vMxEAGn5E3M&oq=Dare+B&gs_lcp=Cgdnd3Mtd2l6EAEYADINCC4QxwEQrwEQQxCTAjICCAAyAggAMgIIADIECAAQCjICCAAyAgguMgIIADICCAAyAgguOggILhDHARCjAjoECAAQQzoECC4QQzoLCC4QsQMQxwEQowI6CAguELEDEIMBOgUIABCxAzoKCAAQsQMQgwEQQzoHCAAQsQMQQzoFCC4QsQM6BwguELEDEEM6CAgAELEDEIMBULyGAljrkAJggZ4CaABwAngAgAGvBYgBjSOSAQM1LTeYAQCgAQGqAQdnd3Mtd2l6wAEB&sclient=gws-wiz</a>><br>
<br>
*Thank you for your enquiry for our parts and services. We offer the<br>
highest-quality spare parts for the vintage Land -Rover. Our staff is<br>
minuscule while the demand for rare and \u201cunobtainable\u201d parts for early<br>
Land-Rovers is relentless. While your concern is important to us, our<br>
ability to respond to each and every enquiry may be limited and stocks of<br>
many items are critically low.. We are primarily a restoration-based<br>
enterprise but when we have a surplus of a given item, we are able to<br>
offer excess stocks to our dedicated clients. If your need is urgent, we<br>
encourage you to contact us by phone, in person. Leaving a message is<br>
rarely effective, so we recommend direct contact. With many buildings full<br>
of parts, it is not always easy to locate obscure items, and the process is<br>
often time consuming. We hope you understand. Please<br>
provide complete details of your exact model including year, wheelbase,<br>
which side drive, engine, Country of origin, etc. When giving part numbers,<br>
please also state the catalogue number (typically found on the front<br>
cover). We appreciate your understanding and will do all we can to help.*<br>
<br>
<br>
Voice 360-866-2254<br>
<br>
<br>
[image: New Logo]<br>
<br>
<br>
On Tue, Aug 19, 2025, 9:00\u202fAM <<a href="mailto:rovernet-request@rovernet.org" target="_blank">rovernet-request@rovernet.org</a>> wrote:<br>
<br>
> Send Rovernet mailing list submissions to<br>
> <a href="mailto:rovernet@rovernet.org" target="_blank">rovernet@rovernet.org</a><br>
><br>
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> than "Re: Contents of Rovernet digest..."<br>
><br>
><br>
> Please edit your digest reply by changing the subject line to the topic to<br>
> which you are referring.<br>
> ************************************<br>
><br>
><br>
> Today's Topics:<br>
><br>
> 1. speedo is nervous (larry williamson)<br>
> 2. Re: speedo is nervous (Steven Dibdin)<br>
><br>
><br>
> ----------------------------------------------------------------------<br>
><br>
> Message: 1<br>
> Date: Tue, 19 Aug 2025 06:31:47 -0600<br>
> From: larry williamson <<a href="mailto:lewill4756@gmail.com" target="_blank">lewill4756@gmail.com</a>><br>
> To: Rovernet <<a href="mailto:rovernet@rovernet.org" target="_blank">rovernet@rovernet.org</a>><br>
> Subject: [Rovernet] speedo is nervous<br>
> Message-ID:<br>
> <<br>
> <a href="mailto:CAPSjzi49d4HqBeHAS0zVe8NQ63yROH6kuS6tKZ9bWhtnWP2X7Q@mail.gmail.com" target="_blank">CAPSjzi49d4HqBeHAS0zVe8NQ63yROH6kuS6tKZ9bWhtnWP2X7Q@mail.gmail.com</a>><br>
> Content-Type: text/plain; charset="utf-8"<br>
><br>
> My speedo is steady sometimes and sometimes jumps around. What is the<br>
> reason and how to fix? I can't seem to find out in the classic forum these<br>
> notes. Larry<br>
> -------------- next part --------------<br>
> An HTML attachment was scrubbed...<br>
> URL: <<br>
> <a href="http://rovernet.org/pipermail/rovernet_rovernet.org/attachments/20250819/b4054e3a/attachment-0001.htm" rel="noreferrer" target="_blank">http://rovernet.org/pipermail/rovernet_rovernet.org/attachments/20250819/b4054e3a/attachment-0001.htm</a><br>
> ><br>
><br>
> ------------------------------<br>
><br>
> Message: 2<br>
> Date: Tue, 19 Aug 2025 14:21:23 +0100<br>
> From: Steven Dibdin <<a href="mailto:sdibdin@gmail.com" target="_blank">sdibdin@gmail.com</a>><br>
> To: Rovernet <<a href="mailto:rovernet@rovernet.org" target="_blank">rovernet@rovernet.org</a>><br>
> Cc: larry williamson <<a href="mailto:lewill4756@gmail.com" target="_blank">lewill4756@gmail.com</a>>, Rovernet<br>
> <<a href="mailto:rovernet@rovernet.org" target="_blank">rovernet@rovernet.org</a>><br>
> Subject: Re: [Rovernet] speedo is nervous<br>
> Message-ID: <<a href="mailto:43FEA171-275D-49AF-AD01-F01EC598F612@gmail.com" target="_blank">43FEA171-275D-49AF-AD01-F01EC598F612@gmail.com</a>><br>
> Content-Type: text/plain; charset=utf-8<br>
><br>
> Which model Rover do you have Larry?<br>
><br>
> Steven<br>
><br>
> Sent from a small screen, please excuse any typos.<br>
><br>
> > On Aug 19, 2025, at 13:32, larry williamson via Rovernet <<br>
> <a href="mailto:rovernet@rovernet.org" target="_blank">rovernet@rovernet.org</a>> wrote:<br>
> ><br>
> > \ufeff<br>
> > My speedo is steady sometimes and sometimes jumps around. What is the<br>
> reason and how to fix? I can't seem to find out in the classic forum these<br>
> notes. Larry<br>
> > _______________________________________________<br>
> > Rovernet mailing list<br>
> > <a href="mailto:Rovernet@rovernet.org" target="_blank">Rovernet@rovernet.org</a><br>
> > <a href="http://rovernet.org/mailman/listinfo/rovernet_rovernet.org" rel="noreferrer" target="_blank">http://rovernet.org/mailman/listinfo/rovernet_rovernet.org</a><br>
><br>
> ------------------------------<br>
><br>
> Subject: Digest Footer<br>
><br>
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> <a href="mailto:Rovernet@rovernet.org" target="_blank">Rovernet@rovernet.org</a><br>
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> ------------------------------<br>
><br>
> End of Rovernet Digest, Vol 143, Issue 3<br>
> ****************************************<br>
><br>
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<br>
------------------------------<br>
<br>
Message: 2<br>
Date: Tue, 19 Aug 2025 13:48:46 -0400<br>
From: "<a href="mailto:magnet@ican.net" target="_blank">magnet@ican.net</a>" <<a href="mailto:magnet@ican.net" target="_blank">magnet@ican.net</a>><br>
To: larry williamson via Rovernet <<a href="mailto:rovernet@rovernet.org" target="_blank">rovernet@rovernet.org</a>><br>
Subject: Re: [Rovernet] speedo is nervous<br>
Message-ID: <<a href="mailto:e7a4c8b4-7266-420c-b65e-b6f0080ad961@ican.net" target="_blank">e7a4c8b4-7266-420c-b65e-b6f0080ad961@ican.net</a>><br>
Content-Type: text/plain; charset=UTF-8; format=flowed<br>
<br>
Hi Larry,<br>
<br>
Speedo issues almost always come down to lubrication, or to be more <br>
precise the lack of it.<br>
<br>
As has been pointed out, the lube in the cable, and if present, in the <br>
right-angle drive behind the speedo head, dries out and gets gummy. <br>
Anything that resists the even turning of the cable, especially up near <br>
the head, can cause jitter, as the cable "winds up" and then "lets go" <br>
once it overcomes the resistance. On the "let go" phase, the cable <br>
momentarily gives a little surge, resulting in a spike in the speedo <br>
reading.<br>
<br>
But a more insidious problem inside the speedo head itself often causes <br>
this surging, and lubricating the cable alone will not eliminate it. <br>
Smiths (aka British Jaeger) speedometers use a little pawl-and-ratchet <br>
arrangement to drive the mileage counter. A worm on the speedo input <br>
shaft turns a pinion gear, and this gear moves a pawl back and forth <br>
every time it goes around. The pawl, in turn, pushes a toothed wheel <br>
around a few degrees on each stroke, and this wheel is coupled to the <br>
tenths-of-a-mile dial of the mileage counter.<br>
<br>
Now what happens when the lubricant of the pawl and the toothed wheel it <br>
drives dries out?<br>
<br>
The wheel gets harder for the pawl to turn. The pawl thus has to work <br>
harder on the forward stroke as it turns the wheel. This causes a <br>
heavier load on the speedo cable, which winds up a bit. But the pawl's <br>
return stroke is easier, and the cable unwinds, giving a flip to the <br>
speedo needle. Depending on your speed, this oscillation takes place a <br>
couple of times each second or faster, resulting in a small but <br>
noticeable jitter in the speedo needle. At some speed, this jitter <br>
coincides with the resonant frequency of the needle and hairspring <br>
assembly and you get a really big swing on the needle.<br>
<br>
But wait, it gets even more interesting! Every time the tenths dial <br>
goes through a revolution, it moves the mile wheel forward by 1. So the <br>
pawl has to work even harder to turn two dials, wnding up the cable even <br>
more, and causing a bigger flip when it relaxes. So once every mile, <br>
you'll get a bigger swing of the needle. And every ten miles, an even <br>
bigger swing, etc.<br>
<br>
Lubricating the pawl is easy, once you have opened up the speedo head, <br>
and greasing the pinion wheel shaft is pretty straightforward too. In <br>
my case, binding of this shaft was the main culprit. Just as well, as <br>
lubrication of the six-wheel dial assembly would have involved more <br>
disassembly than I was prepared to undertake.<br>
<br>
Cheers,<br>
<br>
-- Bill Daddis<br>
<br>
<br>
On 19-Aug-2025 8:31 a.m., larry williamson via Rovernet wrote:<br>
> My speedo is steady sometimes and sometimes jumps around. What is the <br>
> reason and how to fix? I can't seem to find out in the classic forum <br>
> these notes. Larry<br>
><br>
> _______________________________________________<br>
> Rovernet mailing list<br>
> <a href="mailto:Rovernet@rovernet.org" target="_blank">Rovernet@rovernet.org</a><br>
> <a href="http://rovernet.org/mailman/listinfo/rovernet_rovernet.org" rel="noreferrer" target="_blank">http://rovernet.org/mailman/listinfo/rovernet_rovernet.org</a><br>
<br>
------------------------------<br>
<br>
Message: 3<br>
Date: Tue, 19 Aug 2025 18:02:15 +0000 (UTC)<br>
From: Jim Pile <<a href="mailto:jpile1@verizon.net" target="_blank">jpile1@verizon.net</a>><br>
To: Rovernet <<a href="mailto:rovernet@rovernet.org" target="_blank">rovernet@rovernet.org</a>><br>
Subject: Re: [Rovernet] speedo is nervous<br>
Message-ID: <<a href="mailto:293331860.863655.1755626535318@mail.yahoo.com" target="_blank">293331860.863655.1755626535318@mail.yahoo.com</a>><br>
Content-Type: text/plain; charset="utf-8"<br>
<br>
Amazingly detailed info, Bill. Thanks for explaining a ubiquitous issue with the earlier P6 models. <br>
<br>
<br>
Sent from the all new AOL app for iOS<br>
<br>
<br>
On Tuesday, August 19, 2025, 1:49 PM, magnet--- via Rovernet <<a href="mailto:rovernet@rovernet.org" target="_blank">rovernet@rovernet.org</a>> wrote:<br>
<br>
Hi Larry,<br>
<br>
Speedo issues almost always come down to lubrication, or to be more <br>
precise the lack of it.<br>
<br>
As has been pointed out, the lube in the cable, and if present, in the <br>
right-angle drive behind the speedo head, dries out and gets gummy. <br>
Anything that resists the even turning of the cable, especially up near <br>
the head, can cause jitter, as the cable "winds up" and then "lets go" <br>
once it overcomes the resistance. On the "let go" phase, the cable <br>
momentarily gives a little surge, resulting in a spike in the speedo <br>
reading.<br>
<br>
But a more insidious problem inside the speedo head itself often causes <br>
this surging, and lubricating the cable alone will not eliminate it. <br>
Smiths (aka British Jaeger) speedometers use a little pawl-and-ratchet <br>
arrangement to drive the mileage counter. A worm on the speedo input <br>
shaft turns a pinion gear, and this gear moves a pawl back and forth <br>
every time it goes around. The pawl, in turn, pushes a toothed wheel <br>
around a few degrees on each stroke, and this wheel is coupled to the <br>
tenths-of-a-mile dial of the mileage counter.<br>
<br>
Now what happens when the lubricant of the pawl and the toothed wheel it <br>
drives dries out?<br>
<br>
The wheel gets harder for the pawl to turn. The pawl thus has to work <br>
harder on the forward stroke as it turns the wheel. This causes a <br>
heavier load on the speedo cable, which winds up a bit. But the pawl's <br>
return stroke is easier, and the cable unwinds, giving a flip to the <br>
speedo needle. Depending on your speed, this oscillation takes place a <br>
couple of times each second or faster, resulting in a small but <br>
noticeable jitter in the speedo needle. At some speed, this jitter <br>
coincides with the resonant frequency of the needle and hairspring <br>
assembly and you get a really big swing on the needle.<br>
<br>
But wait, it gets even more interesting! Every time the tenths dial <br>
goes through a revolution, it moves the mile wheel forward by 1. So the <br>
pawl has to work even harder to turn two dials, wnding up the cable even <br>
more, and causing a bigger flip when it relaxes. So once every mile, <br>
you'll get a bigger swing of the needle. And every ten miles, an even <br>
bigger swing, etc.<br>
<br>
Lubricating the pawl is easy, once you have opened up the speedo head, <br>
and greasing the pinion wheel shaft is pretty straightforward too. In <br>
my case, binding of this shaft was the main culprit. Just as well, as <br>
lubrication of the six-wheel dial assembly would have involved more <br>
disassembly than I was prepared to undertake.<br>
<br>
Cheers,<br>
<br>
-- Bill Daddis<br>
<br>
<br>
On 19-Aug-2025 8:31 a.m., larry williamson via Rovernet wrote:<br>
> My speedo is steady sometimes and sometimes jumps around. What is the <br>
> reason and how to fix? I can't seem to find out in the classic forum <br>
> these notes. Larry<br>
><br>
> _______________________________________________<br>
> Rovernet mailing list<br>
> <a href="mailto:Rovernet@rovernet.org" target="_blank">Rovernet@rovernet.org</a><br>
> <a href="http://rovernet.org/mailman/listinfo/rovernet_rovernet.org" rel="noreferrer" target="_blank">http://rovernet.org/mailman/listinfo/rovernet_rovernet.org</a><br>
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<br>
Message: 4<br>
Date: Tue, 19 Aug 2025 20:11:24 -0700<br>
From: Gordon Reddy <<a href="mailto:gorgowof@gmail.com" target="_blank">gorgowof@gmail.com</a>><br>
To: Rovernet <<a href="mailto:rovernet@rovernet.org" target="_blank">rovernet@rovernet.org</a>><br>
Subject: Re: [Rovernet] speedo is nervous<br>
Message-ID:<br>
<CAGxhdkEjvR_Gaix=mNoYh0kNte+ZtZXbU8V=<a href="mailto:JPjjdECeL4wgow@mail.gmail.com" target="_blank">JPjjdECeL4wgow@mail.gmail.com</a>><br>
Content-Type: text/plain; charset="utf-8"<br>
<br>
Amazing! I will try this on my P5 this winter, thank you Bill!<br>
Gord Reddy<br>
<br>
On Tue, 19 Aug 2025 at 11:03, Jim Pile via Rovernet <<a href="mailto:rovernet@rovernet.org" target="_blank">rovernet@rovernet.org</a>><br>
wrote:<br>
<br>
> Amazingly detailed info, Bill. Thanks for explaining a ubiquitous issue<br>
> with the earlier P6 models.<br>
><br>
><br>
> Sent from the all new AOL app for iOS<br>
> <<a href="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" rel="noreferrer" target="_blank">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</a>><br>
><br>
> On Tuesday, August 19, 2025, 1:49 PM, magnet--- via Rovernet <<br>
> <a href="mailto:rovernet@rovernet.org" target="_blank">rovernet@rovernet.org</a>> wrote:<br>
><br>
> Hi Larry,<br>
><br>
> Speedo issues almost always come down to lubrication, or to be more<br>
> precise the lack of it.<br>
><br>
> As has been pointed out, the lube in the cable, and if present, in the<br>
> right-angle drive behind the speedo head, dries out and gets gummy.<br>
> Anything that resists the even turning of the cable, especially up near<br>
> the head, can cause jitter, as the cable "winds up" and then "lets go"<br>
> once it overcomes the resistance. On the "let go" phase, the cable<br>
> momentarily gives a little surge, resulting in a spike in the speedo<br>
> reading.<br>
><br>
> But a more insidious problem inside the speedo head itself often causes<br>
> this surging, and lubricating the cable alone will not eliminate it.<br>
> Smiths (aka British Jaeger) speedometers use a little pawl-and-ratchet<br>
> arrangement to drive the mileage counter. A worm on the speedo input<br>
> shaft turns a pinion gear, and this gear moves a pawl back and forth<br>
> every time it goes around. The pawl, in turn, pushes a toothed wheel<br>
> around a few degrees on each stroke, and this wheel is coupled to the<br>
> tenths-of-a-mile dial of the mileage counter.<br>
><br>
> Now what happens when the lubricant of the pawl and the toothed wheel it<br>
> drives dries out?<br>
><br>
> The wheel gets harder for the pawl to turn. The pawl thus has to work<br>
> harder on the forward stroke as it turns the wheel. This causes a<br>
> heavier load on the speedo cable, which winds up a bit. But the pawl's<br>
> return stroke is easier, and the cable unwinds, giving a flip to the<br>
> speedo needle. Depending on your speed, this oscillation takes place a<br>
> couple of times each second or faster, resulting in a small but<br>
> noticeable jitter in the speedo needle. At some speed, this jitter<br>
> coincides with the resonant frequency of the needle and hairspring<br>
> assembly and you get a really big swing on the needle.<br>
><br>
> But wait, it gets even more interesting! Every time the tenths dial<br>
> goes through a revolution, it moves the mile wheel forward by 1. So the<br>
> pawl has to work even harder to turn two dials, wnding up the cable even<br>
> more, and causing a bigger flip when it relaxes. So once every mile,<br>
> you'll get a bigger swing of the needle. And every ten miles, an even<br>
> bigger swing, etc.<br>
><br>
> Lubricating the pawl is easy, once you have opened up the speedo head,<br>
> and greasing the pinion wheel shaft is pretty straightforward too. In<br>
> my case, binding of this shaft was the main culprit. Just as well, as<br>
> lubrication of the six-wheel dial assembly would have involved more<br>
> disassembly than I was prepared to undertake.<br>
><br>
> Cheers,<br>
><br>
> -- Bill Daddis<br>
><br>
><br>
> On 19-Aug-2025 8:31 a.m., larry williamson via Rovernet wrote:<br>
> > My speedo is steady sometimes and sometimes jumps around. What is the<br>
> > reason and how to fix? I can't seem to find out in the classic forum<br>
> > these notes. Larry<br>
> ><br>
> > _______________________________________________<br>
> > Rovernet mailing list<br>
> > <a href="mailto:Rovernet@rovernet.org" target="_blank">Rovernet@rovernet.org</a><br>
> > <a href="http://rovernet.org/mailman/listinfo/rovernet_rovernet.org" rel="noreferrer" target="_blank">http://rovernet.org/mailman/listinfo/rovernet_rovernet.org</a><br>
><br>
> _______________________________________________<br>
> Rovernet mailing list<br>
> <a href="mailto:Rovernet@rovernet.org" target="_blank">Rovernet@rovernet.org</a><br>
> <a href="http://rovernet.org/mailman/listinfo/rovernet_rovernet.org" rel="noreferrer" target="_blank">http://rovernet.org/mailman/listinfo/rovernet_rovernet.org</a><br>
><br>
> _______________________________________________<br>
> Rovernet mailing list<br>
> <a href="mailto:Rovernet@rovernet.org" target="_blank">Rovernet@rovernet.org</a><br>
> <a href="http://rovernet.org/mailman/listinfo/rovernet_rovernet.org" rel="noreferrer" target="_blank">http://rovernet.org/mailman/listinfo/rovernet_rovernet.org</a><br>
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<br>
Message: 5<br>
Date: Wed, 20 Aug 2025 05:22:46 -0600<br>
From: larry williamson <<a href="mailto:lewill4756@gmail.com" target="_blank">lewill4756@gmail.com</a>><br>
To: Rovernet <<a href="mailto:rovernet@rovernet.org" target="_blank">rovernet@rovernet.org</a>><br>
Subject: Re: [Rovernet] speedo is nervous<br>
Message-ID:<br>
<CAPSjzi5Q6=eXv8gUNP3L5oSd4OxJsL378x7KES0eGxbKzVa=<a href="mailto:Jw@mail.gmail.com" target="_blank">Jw@mail.gmail.com</a>><br>
Content-Type: text/plain; charset="utf-8"<br>
<br>
Thank for all that responded. Now the work begins. Larry<br>
<br>
On Tue, Aug 19, 2025 at 9:12\u202fPM Gordon Reddy via Rovernet <<br>
<a href="mailto:rovernet@rovernet.org" target="_blank">rovernet@rovernet.org</a>> wrote:<br>
<br>
> Amazing! I will try this on my P5 this winter, thank you Bill!<br>
> Gord Reddy<br>
><br>
> On Tue, 19 Aug 2025 at 11:03, Jim Pile via Rovernet <<a href="mailto:rovernet@rovernet.org" target="_blank">rovernet@rovernet.org</a>><br>
> wrote:<br>
><br>
>> Amazingly detailed info, Bill. Thanks for explaining a ubiquitous issue<br>
>> with the earlier P6 models.<br>
>><br>
>><br>
>> Sent from the all new AOL app for iOS<br>
>> <<a href="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" rel="noreferrer" target="_blank">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</a>><br>
>><br>
>> On Tuesday, August 19, 2025, 1:49 PM, magnet--- via Rovernet <<br>
>> <a href="mailto:rovernet@rovernet.org" target="_blank">rovernet@rovernet.org</a>> wrote:<br>
>><br>
>> Hi Larry,<br>
>><br>
>> Speedo issues almost always come down to lubrication, or to be more<br>
>> precise the lack of it.<br>
>><br>
>> As has been pointed out, the lube in the cable, and if present, in the<br>
>> right-angle drive behind the speedo head, dries out and gets gummy.<br>
>> Anything that resists the even turning of the cable, especially up near<br>
>> the head, can cause jitter, as the cable "winds up" and then "lets go"<br>
>> once it overcomes the resistance. On the "let go" phase, the cable<br>
>> momentarily gives a little surge, resulting in a spike in the speedo<br>
>> reading.<br>
>><br>
>> But a more insidious problem inside the speedo head itself often causes<br>
>> this surging, and lubricating the cable alone will not eliminate it.<br>
>> Smiths (aka British Jaeger) speedometers use a little pawl-and-ratchet<br>
>> arrangement to drive the mileage counter. A worm on the speedo input<br>
>> shaft turns a pinion gear, and this gear moves a pawl back and forth<br>
>> every time it goes around. The pawl, in turn, pushes a toothed wheel<br>
>> around a few degrees on each stroke, and this wheel is coupled to the<br>
>> tenths-of-a-mile dial of the mileage counter.<br>
>><br>
>> Now what happens when the lubricant of the pawl and the toothed wheel it<br>
>> drives dries out?<br>
>><br>
>> The wheel gets harder for the pawl to turn. The pawl thus has to work<br>
>> harder on the forward stroke as it turns the wheel. This causes a<br>
>> heavier load on the speedo cable, which winds up a bit. But the pawl's<br>
>> return stroke is easier, and the cable unwinds, giving a flip to the<br>
>> speedo needle. Depending on your speed, this oscillation takes place a<br>
>> couple of times each second or faster, resulting in a small but<br>
>> noticeable jitter in the speedo needle. At some speed, this jitter<br>
>> coincides with the resonant frequency of the needle and hairspring<br>
>> assembly and you get a really big swing on the needle.<br>
>><br>
>> But wait, it gets even more interesting! Every time the tenths dial<br>
>> goes through a revolution, it moves the mile wheel forward by 1. So the<br>
>> pawl has to work even harder to turn two dials, wnding up the cable even<br>
>> more, and causing a bigger flip when it relaxes. So once every mile,<br>
>> you'll get a bigger swing of the needle. And every ten miles, an even<br>
>> bigger swing, etc.<br>
>><br>
>> Lubricating the pawl is easy, once you have opened up the speedo head,<br>
>> and greasing the pinion wheel shaft is pretty straightforward too. In<br>
>> my case, binding of this shaft was the main culprit. Just as well, as<br>
>> lubrication of the six-wheel dial assembly would have involved more<br>
>> disassembly than I was prepared to undertake.<br>
>><br>
>> Cheers,<br>
>><br>
>> -- Bill Daddis<br>
>><br>
>><br>
>> On 19-Aug-2025 8:31 a.m., larry williamson via Rovernet wrote:<br>
>> > My speedo is steady sometimes and sometimes jumps around. What is the<br>
>> > reason and how to fix? I can't seem to find out in the classic forum<br>
>> > these notes. Larry<br>
>> ><br>
>> > _______________________________________________<br>
>> > Rovernet mailing list<br>
>> > <a href="mailto:Rovernet@rovernet.org" target="_blank">Rovernet@rovernet.org</a><br>
>> > <a href="http://rovernet.org/mailman/listinfo/rovernet_rovernet.org" rel="noreferrer" target="_blank">http://rovernet.org/mailman/listinfo/rovernet_rovernet.org</a><br>
>><br>
>> _______________________________________________<br>
>> Rovernet mailing list<br>
>> <a href="mailto:Rovernet@rovernet.org" target="_blank">Rovernet@rovernet.org</a><br>
>> <a href="http://rovernet.org/mailman/listinfo/rovernet_rovernet.org" rel="noreferrer" target="_blank">http://rovernet.org/mailman/listinfo/rovernet_rovernet.org</a><br>
>><br>
>> _______________________________________________<br>
>> Rovernet mailing list<br>
>> <a href="mailto:Rovernet@rovernet.org" target="_blank">Rovernet@rovernet.org</a><br>
>> <a href="http://rovernet.org/mailman/listinfo/rovernet_rovernet.org" rel="noreferrer" target="_blank">http://rovernet.org/mailman/listinfo/rovernet_rovernet.org</a><br>
>><br>
> _______________________________________________<br>
> Rovernet mailing list<br>
> <a href="mailto:Rovernet@rovernet.org" target="_blank">Rovernet@rovernet.org</a><br>
> <a href="http://rovernet.org/mailman/listinfo/rovernet_rovernet.org" rel="noreferrer" target="_blank">http://rovernet.org/mailman/listinfo/rovernet_rovernet.org</a><br>
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</blockquote></div>