Installation of Speedometer onto a continental quick release wheel hub

[GTs58]

They're a must have on Muscle Bikes though...even though that's the last bike you'll see someone breaking land speed records on. Ha

All show a no go.

 

[GTs58]

They're a must have on Muscle Bikes though...even though that's the last bike you'll see someone breaking land speed records on. Ha

That brought back a memory from years ago. My buddy Brian in Cali has a friend, crazy Bill, that made numerous runs down a hill trying to hit 55mph on his Stingray. He finally did it. The speedo was also checked for accuracy before he attempted his first run, and he was passing vehicles.

 

[acg_schwinn]

Thread 'Spreading Suburban front forks' https://thecabe.com/forum/threads/spreading-suburban-front-forks.242076/
This is the last conversation that was brought up about speedometer drive install. It doesn't cover QR axles, but it does briefly mention needing a longer axle. Trying to find longer QR axles is opening up a whole can of worms where you likely will not find an axle with enough threads cut on it. So you would need to install a regular nutted axle.

Agreed; messing about with trying to fit a Huret hub drive over the end of a QR axle just isn't worth all the drama. I would suggest that if you don't have a genuine need to remove the front wheel very often, now would be the time to swap in a solid axle, and then you can go with the hub drive. I've had one on my Continental for, um, decades now, but prior to that I also swapped the original axle for a Dynohub (with solid axle) back around 1981.

I don't disagree that properly reshaping the front fork geometry to accommodate a little extra width is ideal, but I will admit that when I first assembled mine, I simply pulled the forks slightly further apart by hand until the assembly slid into place, and that was that.

Some other comments in no particular order:

• The outer shell of the drive hub must be parallel to the wheel, so with tubular forks, it may require 2 or more washers between the drive hub and the inner face of the front fork to ensure no contact. The hardware kit supplied with the Huret speedometers provides 3 washers, but you usually need 2 of those on the inner face of the drive to ensure that the housing does not contact the rotating wheel, so you might need one or two more on the outside for a Continental installation. They are nominally 3/8" SAE size and found at most hardware stores. (The SAE designation indicates a smaller outside diameter. Standard 3/8" washers are too wide to fit inside the recess of the drive hub.)
• Regarding the downsized inner core of the drive cables, the older (and much more common ones) are 2.5mm square across the flats at either end. The newer, thinner ones are 1.8mm across the ends. The die-cast collars of the newer cables are the same 10mm size as the old ones, but the barrel of the connector at each end of the casing is stamped with "1.8" to aid in differentiating new cables from older ones at a glance.
• 1.8mm drive cables shipped with a black plastic sleeve adapter to fit a 1.8mm core into the 2.5mm socket of the drive hub. The speedometer head was updated with a 1.8mm socket in the end of the impeller shaft, which is a pain because it can't use the more common older cables as replacements. I always swap in a 2.5mm impeller shaft when rebuilding the newer heads.
• The universal tire drive sets were introduced specifically for QR models beginning in the 1978 consumer catalog. (The catalog actively warned against using the earlier hub drive sets on QR wheels.) There were two sets available depending on frame size (17" through 21" and 22" through 27"), differing only in the length of the short cable used to reach the tire from the handlebars. I believe they all have the same 1.8mm lower end attaching to the tire drive, but the upper end of the core may be either 2.5mm or 1.8mm; I've seen both. The speedometer head of a universal tire drive kit is the same one provided in hub drive kits.
• The universal tire drive is designed to clamp to the tubular front forks of a Continental or similar. The tire drive has a springy metal mounting arm to press a plastic drive wheel against the tire sidewall. The other end of the mounting arm fits a chrome metal strap which clamps around the upper end of the right front fork. The hub of the drive uses an internal drive belt and pulley setup to step down the drive wheel rotation to match the calibration of the speedo head, and since the tire sidewall is moving at road speed regardless of wheel diameter, this can be used on any size of front wheel.
• I have successfully installed a tire drive on the flat forged forks of a Varsity, but had to shim the mounting strap with a couple pieces of wooden paint stirrer stick to give it enough thickness for a solid mounting.
• One point that I don't think has been mentioned yet is that you need a pretty long cable to install a drive hub on a 27" bike. I have a small-to-medium frame size of Continental (most likely the 22"), and the 24½" cable supplied in the original 27" kit will barely span the distance. A larger frame would probably need a longer cable; Schwinn offered a 26" service replacement (08 485) for this purpose.

One point I should emphasize when buying new old stock Huret kits: they are about fifty years old now, and are virtually guaranteed to be seized up internally after sitting in the box for half a century. Rebuilding to free up the seized impeller is essential. Installing a seized-up speedo head can shear off the drive cable core as soon as the bike starts rolling, and a broken drive cable will ruin your entire day, financially. Amateur sellers on eBay who are flipping something they found at an estate sale typically have no idea of how to test the speedo head, and assume that New means Working, which in this case, it does not.

Factory test mileage will always show as 0000.3, so if you see that in the seller's photo, assume that you will need to resolve the seized-up issue before use.

Good grief, I'm on my second cup of coffee already. I should stop here...