Primary Reduction Ratio

8 replies to this topic
  • DPWR400

Posted August 19, 2007 - 08:01 PM


First of all what gears are they using as primary reduction ratio? Second do all DRZ's have the same ratio of 2.960 (74/25). I have an 05 SM but only have a S shop manual. Lastly do all DRZ's use a 15 tooth counter sprocket stock? Thanks All!

  • g935cab

Posted August 19, 2007 - 08:41 PM



s- 15-44

e- 14-47

  • William1

Posted August 20, 2007 - 03:02 AM


Primary for all bikes is 2.960 (74/25)
g935cab gave final ratios

  • DPWR400

Posted August 20, 2007 - 05:32 AM


Cool thanks for the info everyone, but I'm still curious how the primary reduction ratio is computed? Anyone??

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • jlbenne

Posted August 20, 2007 - 06:18 AM


By teeth on the gears and simple division

74 divided by 25 is 2.96

  • MutualBill

Posted August 20, 2007 - 06:39 AM


to calculate final drive ratio of a given gear combination...divide the drive gear by the driven gear (tooth count).

This will give you your gear ratio. For example 15/44 ratio equals .340909090...or you a what is normally known a 3.40 drive ratio.

You multiply that number number by the gear ratio of the gear you have selected in the Transmission to achieve your total final drive ratio. By the way...the DRZ does not have a 1:1 ratio on any of its gears. 4th is slightly under driven and 5th gear is slightly over driven.

If you search...sombody did post the ratio of all 5 gears for the drz in the past.

  • DPWR400

Posted August 20, 2007 - 05:51 PM


okay so the primary drive gear has 25 teeth so that is where the 25 comes from but where does the number 74 come from?

  • DPWR400

Posted August 20, 2007 - 06:08 PM


I think I figured it out, the primary driven gear has to be the clutch basket, is that right??

  • Noble

Posted August 20, 2007 - 10:06 PM


Right. 74 teeth on the clutch basket

Related Content


Suzuki DR-Z400SM 2016 by kiwi-on-wheels

Suzuki DR-Z400SM 2016
  • 9 reviews
  • Last review by E2Moto
  • On April 28, 2016

Suzuki DR-Z400S 2016 by CoryH

Suzuki DR-Z400S 2016
  • 2 reviews
  • Last review by Kenny Blake Rugen
  • On May 20, 2016

Bike Enthusiast Youtube Series by Davnic

Street   General Street Bike Forums   General Street Bike Discussion
  • 2 replies

DRZ400s front fender swap for highway? by webbie1

Dirt Bike   Make / Model Specific   Suzuki   DR-Z 400
  • Hot  35 replies

Suzuki DR-Z400SM 2010 by Akéan1

Suzuki DR-Z400SM 2010
  • 1 review
  • Last review by Akéan1
  • On April 12, 2016

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.