Re: Tr3a (and TR4) speedos

[scharfr@aol.com]

Greetings all:

  To add one more data point to the TR3/4 speedometer thread, I have a 
TR4 with a speedometer calibration number of 1184. For what it's worth, 
it is spot-on accurate at 35 mph, according to those radar feedback 
signs that the police occasionally place on our roads. I'm using 165/15 
Cooper SportMaster tires but can't say, offhand, what axle ratio I have.

 Bob Sharp
 Michigan
 64-ish TR4

 Subject: Tr3a speedos

  >>>>I picked up a replacement speedo for the '3 a little while ago. I 
finally get
  >>>>around to installing it. I notice the "model" number on the face 
is different,
  >>>>mine is a 1180 the replacement is a 1200. Is there a difference I 
should care
 >>>>about? What is the 1200 from?
 ___________________

  >>>The 1200 refers to the calibration, and your new speedometer will 
be
 >>>inaccurate if the 1180 was accurate. Tony Rhodes gives a detailed
  >>>explanation of this in his instructions for repairing speedometers 
at
 >>>http://mywebpages.comcast.net/rhodes/speedo.html
 ___________

  >>Sounds like you're looking at the calibration number, which 
indicates how many
 >>revolutions the speedo cable makes in a traveled mile.


  
http://triumphowners.com/resources.cgi?articleID=111194&parentID=111193&sectionID=111025
 ____________

  >FWIW, the TR2/3/3A Spare Parts Catalogue lists only two speedometers: 
one
  >each for "MILE" and "KILO." The TR4 SPC, though, lists four different 
speedos
 >each for MILE and KILO:

 >One (each) for 5.50/5.90 x 15" tires and 3.7:1 ratio axle
 >One (each) for 5.50/5.90 x 15" tires and 4.1:1 ratio axle

 >One (each) for Michelin X 165 x 15" tires and 3.7:1 ratio axle
  >One (each) for Michelin X 165 x 15" tires and 4.1:1 ratio axle