Hot Rods Speedo with a quick change? Yes or no...

I'm building a traditional hot rod with a quick change rear. It'll have a tach, but should I spend money on a speedo for it?

 

depends..do you want to Know how fast you are going?

Seriously, calibrating and adjusting speedos for two (or more)rear end gears is a pain in the arse, and gets expensive. the Columbia two speed rears came with a little gearbox That sat behind the speedo and swapped the speeds for the speedo when you changed rear end gears.. getting that type of setup to work again would be expensive..but cool.

I believe they are making GPS powered speedos now..solves all your problems, but not very trad. maybe have the guts of one put into a vintage SW or something? hey thats not a bad idea!

 

Any truck with a 2-speed rear end has a gearbox on the back of the speedo. If you are only running two ratios in the quickie, swapping the top and bottom gears, you might be able to find a 'box with the right ratios in a wrecker.

 

I'm thinking that many trucks, larger farm/construction/etc that used 2 speed rear ends also had a little gearbox in the speedo cable system that shifted when the rear end did. Look for it in 50's era Chevs, GMCs, Dodges, International etc.

Ray

 

Back when, guys would calibrate the speedo for their high, cruising gears, and use the tach to figure the error with the other cogs.
I believe the industry standard is 1000 RPM cable speed at 60 MPH.

 

Do you plan on changing the gears very often? Most people get a quickchange for looks. If you are going to drive it on road just set up the speedo for that.

 

figue out what your tach reads at certain speeds with a friend along side in his car, I do that with my flattie with a winters qc. works fine

 

Use your tach and the hi way mile markers and a stop watch. most modern car speedos read 3 mph fast at 60 so barney don't give you a ticket.



Ago

 

Tach is more important but I ran a programmable speedo to compensate for the many gear changes that way I could keep track of the miles I drove on the road trips.

 

http://www.speedometershop.com/ This company is absolutely one of the best imho. I began using them over 50 years ago when working for a BMC dealership. Used to ship all of our Jaguar and BMC speedo's and tach's to them from No. CA on the stage (Greyhound). We were never disappointed. If you can find a two speed speedo box I'm sure that they can change the gearing to whatever it would take for your selection of gearing for your QC. They may already have a solution to what you want to accomplish. A plus is the fact that they are in your neck of the woods.

Hope this helps

 

Use a speedometer. You'll find you won't be changing the gears in the quickchange very often, if at all.

A tachometer will have the same issues when it comes to determining speed after a gear change that the speedometer will; both would require some math.

 

If it is really important to have the speedometer read perfectly all the time, it doesn't seem to me that crawling forward under the car to change the speedo driven gear would be much of a task after changing the gears in the quickie. What's it take, about five minutes, switching to the alternate gear that you could carry in the interior pocket?