Jump to content

Speed vrs rpm vrs gear


Anglefire

Recommended Posts

Remove speedo,  remove rim  undo the two back screws remove the mechanism

Turn the drive disc to the speed shown when driving,  gently move the needle to the desired reading

Hang the stripped out unit in the hole and test to see if you got it right,  reasemble and re fit the glass and rim

Simple for small errors   reading 10%fast is about normmal  used to be 4mph +10%  so at 60 it can read 70

Hardest job is breaking the rubber 0 ring glass seal they go realy sticky

You cant needle twidle for drive line major changes to the turns per mile due to the hair spring hysterisis and magnetic 

Drive flux. and the oddometer gearing  .

Pete

 

Link to comment
Share on other sites

I think mine is more than an offset error - as its out by 10% across the range - so 44 at 40, 55 and 50 etc - so I assume its the wrong gear in the box?

Not that I will change anything unless its simple - pulling the box just for this would be insane. (Though its something I might do for kicks!) 

Link to comment
Share on other sites

Thats within the design spec then  has to be between spot on and 10% fast   cant read slow

As the 'error' is consistent  a needle move should work fine 

Triumph did not do many pinions or worm to  enable one speedo they had different tpm speedos for every model

Pete

 

Link to comment
Share on other sites

4 minutes ago, Pete Lewis said:

As the 'error' is consistent  a needle move should work fine

No, the needle shift applies an offset but Anglefire has a ratiometric error.

 

4 minutes ago, Pete Lewis said:

Triumph did not do many pinions or worm to  enable one speedo they had different tpm speedos for every model

That varied. On early cars they stuck with similar drive ratios and picked the right speedo TPM. From some time in the '70s they standardised on 1000TPM and picked the right drive ratio.

Link to comment
Share on other sites

I've absolutely no idea what mine does, being an 18/50 gearbox with J-type O/D on a non-O/D diff. I just do the speed everyone else is doing unless it's on the motorway / dual carriageway, in which case I just tootle along at an indicated 65 or so and let everyone else overtake me.

  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...