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Speedo drive gear

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4tecdog

4tecdog

Jedi Hopeful
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Anyone know if there is a Speedo drive gear available that would give a more accurate reading for a 19/41 ratio diff on a sprite. The std one looks quite expensive from some suppliers so it would be good to get one that does the job more accurately.
 
Speedhut GPS Speedo. Dead nuts accurate. Works with my 5 speed. Bugeye Guy even sells one with a pretty good imitation of the OEM Smiths Speedo. Mine I created my own faceplate design power and ground and little GPS Magnetic antenna site on the dashboard where it can see the sky. As I was going to a 5 speed i bought a matching Tach. so that's two less cable drive products that I don't have to buy Adapter boxes for at $150+ a pop every other year.
 
Hi Jim thanks for your suggestion I have looked at these and they would be the perfect answer however I run a rally trip meter that takes its pulse from the sender unit spliced into the Speedo cable and that instrument can be accurately calibrated so I would like to keep a cable drive. Also Im not sure if Gps speedometers are approved in the UK to pass the Mot? They really look good though.
 
4tecdog said:
Anyone know if there is a Speedo drive gear available that would give a more accurate reading for a 19/41 ratio diff on a sprite. The std one looks quite expensive from some suppliers so it would be good to get one that does the job more accurately.
Click to expand...

41 divided by 19 gives. 2.16???
 
Should have said 9 not 19 must be an age thing! That equates to 1 to 4.55 previous diff I had was 3.7 and the Speedo was fairly accurate with that.
 
Thanks we have guys who can recalibrate the Speedo here in South Wales, Are you saying there is only one drive gear ? I was hoping to get closer to the correct reading with a different drive gear don’t want to recalibrate the gauge as I may put the original diff back in for cruising. Set up for hill climbs at the moment.
 
Speedo calibration is done in the speedometer head, not via the transmission gear. All the transmission speedometer drive gears are the same. You'd need to change the gearing in the head to recalibrate. This explains the process: http://www.lotus-europa.com/manuals/misc/electrical/Smith-jaeger_speedo_repair.pdf If you wanted it to be "close enough for government work" you could time your car through a measured mile at what feels like 60 mph and determine if the speedo is reading high or low, prise off the speedo needle and replace it so it reads accurately at 60 and you'd be kind of accurate.
 
Much clearer now HealeyRick thanks for the article very informative. I obviously got the wrong end of the stick when I heard you could change the gearing they meant in the Speedo not the gearbox. Think I will go down the recalibration route.
 
There ARE different drive gears available.(at least for the DATSUN tranny) Paul A. had someone in Portland Oregon (a speedometer shop I believe, but can't recall the name) he had them custom made depending upon which diffy and the size of tire one one going to run. ...

That said, I had changed the diffy from when I had the tranny changed. At that point the error in speed was different than the error in the odometer. One was at 15% and the other at almost 20%. ...

I like Mr. Gruber have changed to the Speedhut gauges for both tach and speedo. I liked the style from Bugeyeguy so I went that way. And I LOVE
THEM. No more bouncy speed. No more speed error. accurate tach that doesn't change reported rpm depending upon ambient temperature. I also had installed the programmable fuel gauge. Now ALL my instruments function properly!
 
Pythias said:
There ARE different drive gears available.(at least for the DATSUN tranny) Paul A. had someone in Portland Oregon (a speedometer shop I believe, but can't recall the name) he had them custom made depending upon which diffy and the size of tire one one going to run. ...
That said, I had changed the diffy from when I had the tranny changed. At that point the error in speed was different than the error in the odometer. One was at 15% and the other at almost 20%. ...
Click to expand...

Hi Bill:
Yes, there used to a "Speedometer Repair" in the Pearl District but it's no longer there. There is a company by the same name elsewhere (and I don't know if it's the same guys). I once had them repair a speedo on a '62 Mini. Thankfully, when I sort of inherited a complete Datsun conversion with 3.9 diff (Paul's conversion), the matching gear-drive (an elbow) and speedo were perfect.
Going to ABFM this year? I'll be there.
 
Boink said:
Going to ABFM this year? I'll be there.
Click to expand...

I just registered yesterday. It will be my "reveal". Over the past couple of years I have

Had ALL the rust taken out and the car repainted. I also took off the front bumper and had the holes filled. Never a front bumper again. (2018)
Had the interior completely redone-- door cards, carpet, all panels replaced. Had the front end rebuilt/replaced and installed poly-bushings all around. (2019)
Had the dash repainted (crinkle finish) and as mentioned above replaced the instruments (except the dual gauge). (2020)
Converted to negative ground and installed a genernator. This also required replacement of the CRANE electronic ignition which was + ground only with a newer FAST version.

It is now a "no excuses" car. ... Well, I still need to have the rear bumper re-chromed... .... .... ......
 
Wow! And here you wanted to sell it a few years ago. Now it's surely a serious keeper.

I wonder if ABFM attendance will be way down this year (others think so - probably few out-of-towners). A better chance to win something. I'll help stuff the Sprite ballot box for you. :eek:
 
I had decided that if I couldn't sell it, I could at least give it it's due. When I see you I'll tell you what I've put into it. I for sure can't sell if for that.
 
Bill I’m with you, when investment exceeded $20k I stopped keeping track. Now it just a fun toy with all of the goodies. Will I get money back if and when I sell it. I hope tgat day is a long way away but I do change decades in a few weeks. Tempus Fugit! I realize I bought my ‘68 Sprite back in ‘98 or ‘99. Bugsy IV I’ve owned for 4 or 5 years now. And he’s still not done. Dashboard hopefully gets hung this weekend.
 
I'm sure there are different speedo right angle drive boxes for the Sprite for different ratio differential's. Just don't know where to find them. Google some of the speedo repair folks. Nisonger, Palo Alto and others.

Kurt
 
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