Jump to content
Sign in to follow this  
j_boy_619

Speedometer ratio?

Recommended Posts

Whats the gear ratio for the speedometer on a 1975 B210 with a 5speed?

I have only done swaps on old jap motorcycles so Im used to 60MPH=2240RPM. But I'm assuming cars are different. ELI5

Share this post


Link to post

having some troubles finding a speedometer matching that ratio. Do other dats use 60:1024? Any other car makes?

Share this post


Link to post

1975 didn't have an available 5 speed, therefor it was a swap. First you have to determine which tranny your "B" originally had in it. This will help you to determin the differential gear ratio.

Seeing that it was a swap, you will need to determin which 5 spd was used.

 

An easy way, if you have a smart phone, is to download a GPS-MPH app. When you reach 60mph, check your tachometer for the rpm's. Obviously this entails having a tachometer installed in your "B" also.

Share this post


Link to post

Whats the gear ratio for the speedometer on a 1975 B210 with a 5speed?

I have only done swaps on old jap motorcycles so Im used to 60MPH=2240RPM. But I'm assuming cars are different. ELI5

 

Internally, the '75 4 speed and the later '76 and up 5 speed both used a 17 tooth speedometer drive pinion in the tailstock. Unless you have changed the rear gearing or have taller tires the speedometer will read the same.

Share this post


Link to post

By all means pull the speedo cogs out of the transmissions and compare them for number of teeth. I'll check butIIRC  Black plastic is the color code for 17 tooth.

Share this post


Link to post

so i need a speedometer that uses 17 teeth?

Share this post


Link to post

so i need a speedometer that uses 17 teeth?

 

No, you need a 17-tooth speedo pinion.   ;)

Share this post


Link to post

The little plastic gear on your speedo pinion (bolts to the side of the trans and speedo cable connects to it) comes in many different sizes. 

 

speedo_pinions.jpg

Share this post


Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.