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Could you see it if you had a mechanic’s mirror?
I have one that has a small mirror on the end of expandable handle.
The mirror rotates and the handle extends about 18”.
OldCarBum --- I don't have a mirror like that but my concern at this time has nothing to do with being able to see things; I can see what I need to see well enough to do the work. My concern has to to do with being able to maneuver in a tight spot. Removing something like I did with my old speedometer cable adaptor is one thing since all the precision work of installing it was done by someone else and I'm just unscrewing things. Installing it again -- especially when you might need to have to align things as you're doing it or need 2 hands at once -- is something altogether different. It'd be somewhat analogous to trying to change your clothes in a phone booth. I'm sure I'll get through it. But, before I can move forward on anything, I need the darned Speedometer Cables USA company to contact me! Maybe I'll have to resort to the old school method of actually calling them on the phone! How primitive!!
After removing the existing adaptor (and concluding that it's shot, as I noted earlier), I found these interesting markings on it (see pictures).
This appears to show the manufacturer as Hubbard. Not sure what to make of what looks like a capital letter "W" since there's no W in Hubbard.
This photo appears to show a part number (647887) and a reduction ratio of 1:.882. If you can zoom the picture, you can see the ratio more clearly.
Doing internet searches on "Hubbard" and "647887" yielded absolutely nothing related to speedometers.
I'm assuming that the 1:.882 reduction ratio is implying that 1 turn of the adaptor's input shaft (coming out of the transmission) is being reduced by the adaptor to .882 turns of the adaptor's output shaft (which turns the actual speedometer cable).
It's not possible for me to validate this since, as I mentioned, the adaptor is not trustworthy -- sometimes turning the adaptor's input end (using the drive pin that fits into the transmission's driven gear) will turn the adaptor's output end (which spins the speedometer cable) and sometimes it won't spin the adaptor's output shaft at all.
So, again, I can't use the adaptor itself to confirm my guess about which end spins once while the other end spins only .882 times.
Anyway, I just wanted to share more information with you guys in hopes that someone might recognize "Hubbard" and/or recognize the part number stamping and/or have factual information about the stamped ratio and which direction the ratio applies.
Many companies that made things like that have come and gone over the years, not surprising there's little info out there.
If you are looking to correct the over-reading you have now you might have luck with these guys
speedometer cables usa
M
Many companies that made things like that have come and gone over the years, not surprising there's little info out there.
If you are looking to correct the over-reading you have now you might have luck with these guys
speedometer cables usa
M
Yep. I mentioned in an earlier post that I’m waiting for them to contact me back!
Trying to get my cable and hope from transmission.
I realize this is an old thread but I am just now dealing with this on my 68. There's no way to get your hand let alone a tool past the exhaust bracket to grip the speedometer cable. I need to change the driven gear as my speedometer is off about 10 mile an hour. How did you end up getting it off and reattached?
Stevewv --- I did mention earlier in this thread that I was able to get the adaptor-plus-speedo-cable off as a unit. I was able to get a long handled slip-jaw (ChannelLocks) pliers in by inserting the pliers towards the adaptor fitting from the rear of the car. The car was up on jack stands and I was laying under it with my feet toward the engine and my head towards the rear of the car. There was just enough swing room to grip the knurled fitting with the ChannelLocks and get it loose. Once loose, there was very limited clearance to work it off the transmission body because the adaptor came into contact with the floor pan of the car as I extracted it from the side of the transmission and that limited how far it could actually move laterally. With a fair amount of wriggling around, I managed to get both my hands into that area from 2 different directions and used my left hand to keep the drive key (the ‘pin’ that connects the driven gear to the adaptor) fully seated in the transmission, thereby minimizing how much of that drive key was protruding. Doing so allowed me to get the adaptor-plus-speedo-cable completely off. Once that assembly was off, I unclipped the speedo cable from a clip on the underside of the floorpan and then there was plenty of slack to remove the cable from the adaptor. I took the drive pin out of the transmission body, too, so that it would not get misplaced.
In my case, the speedo cable itself was just fine; I spun it gently with a cordless drill and it registered on the speedometer as I hoped. The adaptor wasn’t so fine. When I spun the drive key in it by hand, it would sometimes turn the end that drives the speedo cable and sometimes wouldn’t. So, it was clearly shot and I bought a new one. And, while I was at it, I bought one with the proper gearing ratio so that my speedometer showed TRUE speed.
Consequently, I would actually recommend against trying to change your driven gear in the transmission body because I think that would be more difficult than swapping out the 90-degree adaptor for one with the proper gearing in it. You already see how tight it is to get the adaptor off. Imagine trying to remove and reinstall a drive gear. IMPOSSIBLE!
While we are talking about gearing, you say that you're "10 miles per hour off" on your speedo reading. But, I'm guessing that it's not a constant 10MPH off. For example, if you're rolling at a true 20MPH, your speedo maybe shows 23MPH. If you're rolling at a true 40MPH, your speedo maybe shows 46MPH. In other words, it's more than likely a PERCENTAGE off and not a flat MPH off. If what you say were true, you'd always read 10MPH too high and that just doesn't make sense. If that were the case, you'd be reading 15MPH when going 5MPH and you'd be reading 70MPH when going 60MPH. Gearing and drive ratios are all 1:xx in nature so I don't think that's possible. I suspect that maybe you're "10MPH too high at normal highway speeds"... or something like that.
In any case, if you want to swap the drive gear inside the transmission, I can't help you there. BUT, if you want to solve your speedo display discrepancy via getting a 90-degree adaptor with the proper built-in gear ratio, I would HIGHLY recommend Deluxe Speedometer and Cable Service out of Denver, CO. Their website is https://deluxespeedometer.com/. On that site, you'll see a section called Cables and Adaptors and, within there, a section called Gear Box Adapters. You'll see dozens and dozens of ratios that you can order. Call them and speak with John; he will help you out. (For what it's worth, their adaptors are slightly more compact than the one I originally had which made maneuvering it around in tight spaces easier.)
BUT, before calling them, do some "on the road" testing using your car and a pace car that has a speedometer that you can trust. Have your pace car drive 30MPH and then you can pace them; make note of what YOUR speedo is showing. You could also have your pace car drive 50MPH and, pacing them, make note of what YOUR speedo is showing there, too.
Maybe your results look like this (apologies on the formatting; I couldn't get this to look 'nice'):
Then, get the calculator out. To find the right adaptor, you need to figure out what gearing factor will take the speed shown on YOUR speedo and make it show what the pace car (actual speed) was showing. That's a very straight-forward math problem. Solve the following for X
X = ( your speedometer reading / pace car speedometer reading ) which is the same as X = ( your speedometer reading / actual road speed)
. In our example, X would equal 30/33 which means an adaptor with a ratio of .9091 would be your best bet which will decrease what your speedo shows. They may not offer a .9091 but John will help you to find one that is close. (You will note that your other speed comparison of 50MPH vs 55MPH sill results in the same ratio: 50/55 = .9091.)
If your speedo is reading low, the math is identical to above but you'd ultimately need a gear UP adaptor with a ratio of 1.xxxx since you need to increase what your speedometer is showing.
One last tidbit: If you buy an adaptor from the company I mentioned above, you are allowed one free gear change. That is, if you order a, say, .0812 adaptor and you find out your speed still isn't quite where you'd like it, you can send it back for one free gear swap and they'll swap the gearing and send it back to you.
I know that was more than you asked for but I hope all of it helps!
Last edited by sschultz2929; Jun 20, 2022 at 11:32 AM.
