How does gear ratio affect Torque


First....What is torque?:

Torque is a twisting force- (it doesn't do any 'work' itself- it is simple an application of energy). 

Work (or 'stuff') happens, when torque is applied and movement occurs.
"Torque is a force that tends to rotate or turn things. You generate a torque any time you apply a force using a wrench. Tightening the lug nuts on your wheels is a good example. When you use a wrench, you apply a force to the handle. This force creates a torque on the lug nut, which tends to turn the lug nut. 

English units of torque are pound-inches or pound-feet; the SI unit is the Newton-meter. Notice that the torque units contain a distance and a force. To calculate the torque, you just multiply the force by the distance from the center. In the case of lug nuts, if the wrench is a foot long, and you put 200 pounds of force on it, you are generating 200 pound-feet of torque. If you use a two-foot wrench, you only need to put 100 pounds of force on it to generate the same torque." 

In summary:
Torque equals Force multiplied by Distance

How does gear ratio affect Torque?
Simply put, torque at work (such as at a wheel) is your motor's torque times your gear ratio.
Motor Torque x gear ratio = torque at the wheel
Lets say we have a 10rmps motor that is capable of 5 oz Torque (we know this from our motor spec.)

Lets say we have 2 gears. Our input gear (attached to our motor) has 10 teeth Our output gear has 50 teeth

Our Gear ratio is 5:1

Motor Torque x gear ratio = torque at the wheel

5oz x 5:1 = 25 oz

What if our gear ratio were 1:3 ?

5oz x 1:3 = 1.6oz

56 Responses so far.

  1. Unknown says:

    thank you, my concept about torque are much clear than before.
    continue doing this you will achieve succes in your carrier.

  2. Unknown says:
    This comment has been removed by the author.
  3. Unknown says:

    As you wrote above: "In the case of lug nuts, if the wrench is a foot long, and you put 200 pounds of force on it, you are generating 200 pound-feet of torque. If you use a two-foot wrench, you only need to put 100 pounds of force on it to generate the same torque." So, can I understand that bigger engines, like american big block V8s, can generate more torque than smaller engines, whilst they have bigger connecting rods?

  4. Unknown says:

    Thanks for sharing post. Michelin tyres in Pune are available the best at Shree tyres. The best service in the area and very competitive rates.

  5. Unknown says:

    Yes fun w 2 gears so if it were 3 or more is the math the same-
    5:1:5 would be 5.

  6. Unknown says:

    Thank you for the article , it ‘s really nice and useful
    water treatment equipments

  7. Unknown says:

    Indeed a very useful information and May Allah bless you for sharing!

  8. Unknown says:

    Indeed a very useful information and May Allah bless you for sharing!

  9. Unknown says:

    Thanks for the post, hope so that this will help in looking beautiful for longer time.

    dosing metering pump manufacturer in india | chemical dosing system | water treatment equipments

  10. Where you get the formula of this:
    "Motor Torque x gear ratio = torque at the wheel"
    you should put citation.

  11. No. 5:1:5 would cancel. Take this example of a 5:1:5. A 40 tooth gear drives an 8 tooth gear(5:1) yeilds 5, but the next change is 8 teeth driving 40 teeth (1:5) yeilding 0.2, the third gear has the same torque as the first because you multiply by 5 then by 0.2 which equals 1, so there is no change. One might ask, "Why bother with such a set-up?" The 3rd gear is rotating in the same direction as the first. If you simple went 40:40 (1:1), while the second gear would have the same torque it would be rotating in the opposite direction.

  12. No. 5:1:5 would cancel. Take this example of a 5:1:5. A 40 tooth gear drives an 8 tooth gear(5:1) yeilds 5, but the next change is 8 teeth driving 40 teeth (1:5) yeilding 0.2, the third gear has the same torque as the first because you multiply by 5 then by 0.2 which equals 1, so there is no change. One might ask, "Why bother with such a set-up?" The 3rd gear is rotating in the same direction as the first. If you simple went 40:40 (1:1), while the second gear would have the same torque it would be rotating in the opposite direction.

  13. Voldy says:

    Hey ive a doubt,what if the smaller wheel were to be run by the bigger wheel,lets say for instance a 22 teeth wheel drives(input gear) a 11 toothwheel(output gear) then wouldn't the torque be more,since for one single rotation of the larger whell the smaller will rotate 2 times?can i get an answer ?

  14. Voldy says:

    Hey ive a doubt,what if the smaller wheel were to be run by the bigger wheel,lets say for instance a 22 teeth wheel drives(input gear) a 11 toothwheel(output gear) then wouldn't the torque be more,since for one single rotation of the larger whell the smaller will rotate 2 times?can i get an answer ?

  15. Voldy says:

    Hey ive a doubt,what if the smaller wheel were to be run by the bigger wheel,lets say for instance a 22 teeth wheel drives(input gear) a 11 toothwheel(output gear) then wouldn't the torque be more,since for one single rotation of the larger whell the smaller will rotate 2 times?can i get an answer ?

  16. John j says:

    In a 1:1 would the size of the sprocket make a difference? we adjusted the speed of a machine at work that was #60 chain on a 23t to 16t by swapping the gears... the change was to much. I suggested going 1:1. Any reason to use 23t&23 vs 16t&16t (as far as speed and/or tq?) Thanks

  17. Nimesh says:

    Thanks this was really helpful.

  18. Unknown says:

    I should tell you: everyone in America with the hot rod V8 knows that.

  19. Unknown says:

    Yes, of course. Bigger engines generate more torque than a smaller engines as they have longer links and greater force as well.

  20. Unknown says:

    What are some good books for this topic... please suggest

  21. Go to www.slideshare.com and look for "The Gear Book" or simpler but product specific "Gears: Lego Mindstorms"

    I would also suggest orderimg some parts for the old Lego Dacta set 1030 and view the construction guides online for set 1031. The best way to better understand gears is to play around with them and Lego provides an excellent beginners hands-on platform.

  22. Unknown says:

    thank you for this information this hillbilly finaly at age 50 understands why 5-1 is faster than 10-1 on power input , i have been setting my gears up backwards and then i have to come up with huge powerful motors to run my inventions , thanks i now can build a hydrogen fueled car that works , yeay! keep up the simple explanations guys and i may be able to change the world by understanding things you have tought me thanks again !!

  23. Unknown says:

    If a motor HV a speed of 30000rpm and I can reduce this by 3000rpm using gears and how it will affect torque any relationship is there for this one...any on tell me

  24. So here is how to make 2 kg move 12 kg and the same speed
    https://photos.app.goo.gl/EXqXM6UDNJeLhHKH2
    To make a 1 to 1 ratio increase strength. Sadly there are no mechanics or people interested in anything where i live. Hopefully i can relocate somewhere

  25. So here is how to make 2 kg move 12 kg at the same speed
    https://photos.app.goo.gl/EXqXM6UDNJeLhHKH2
    To make a 1 to 1 ratio increase strength. Sadly there are no mechanics or people interested in anything where i live. Hopefully i can relocate somewhere

  26. This comment has been removed by the author.
  27. Anonymous says:

    Hi, I was hoping to get some advice.
    I was reading about gears on the site. I have a 2011 p71 Crown Vic. If I want low end acceleration (I don't care about going above 100mph) what ratio would I want?
    Thank you for your time,

  28. Anonymous says:

    Hi, I was hoping to get some advice.
    I was reading about gears on the site. I have a 2011 p71 Crown Vic. If I want low end acceleration (I don't care about going above 100mph) what ratio would I want?
    Thank you for your time,

  29. Very informative and impressive post you have written, this is quite interesting and i have went through it completely, an upgraded information is shared, keep sharing such valuable information. Styling Short Courses

  30. fantastic post, very informative. I wonder why the other experts of this sector don't notice this. You should continue your writing. I am sure, you have a huge readers' base already! Car sevice from Rome to Sorrento

  31. Good article. We have certified and professional
    medical staff who always care of patients. For more details,
    alcohol detox center in amritsar
    drug detox center in punjab
    best rehab centre in amritsar

  32. Anonymous says:

    Nasha Mukti Kendra in Chandigarh provides substance abuse and de-addiction programs that focus on approachable and realistic behaviours that help the clients overcome their addictions.

  33. Anonymous says:


    Nasha Mukti Kendra in Mohalii one of the best rehabilitation center in Punjab for recovery from drug abuses and alcohol abuses those people who are suffering from the alcohol abuses or drug abuses facing health issues like anxitiness, depression and so other kind of mental and physical health problem nasha mukti Kendra in Punjab help them to recover from their any kind of abuses. 

  34. This comment has been removed by the author.
  35. ITSGURI is the Best Digital marketing Agency in India which help businesses to get real result through social media, SEO, SMM, Google Adowrds, Guest Posting and Website Designing. We are Passionate About Everything Digital Marketing and can Quickly Learn Anything That May Be Needed For Your Project Success with a creative solution.

  36. ITSGURI Digital Marketing Solutions help brands to grow their business with Premium Blogger Outreach & Guest Posting Services. We craft a well-researched and unique article that incorporates your website links and post on targeted high quality sites by doing manual outreach through Paid tools which can boost your brand visibility and traffic by quality content creation, outreach, and placement by our guest blogging experts.

  37. This comment has been removed by the author.
  38. ITSGURI Digital Marketing Solutions help brands to grow their business with Premium Blogger Outreach & Guest Posting Services. We have a collection of high quality sites with Do-Follow Permanent Backlinks that outreached by our Guest bloggers experts through Paid tools which can boost your brand visibility, traffic and can improve your Search Ranking at an Afforadable pricing.

  39. Thanks for sharing such valuable information. I appreciate the time you have given to writing this blog.
    Semi Automatic Paper Cutting Machine

  40. zooomcity says:

    1 bhk flat for sale in chembur - Mass Metroplis "Now is the time to book. Take advantage of this opportunity to live in luxury
    You can reach us at +91908242005
    You can find more information on our website.
    https://zooomcity.com/"

  41. zooomcity says:

    Grace Urban Development Corporations Mass metropolis -Landscaped by international designer | Open spa space | Dedicated children’s play area with a sand pit, swings and slides | Amphitheatre (open air) Jogging & walking track | Reading corner & Senior citizen corner | 30,000 sq. ft. Landscape Garden

  42. Contact us today to learn more about our PCD Pharma Franchise in Zirakpur opportunities.

  43. Thank you for sharing such amazing content. I would like to share my articles , we provide PCD Pharma Franchise in Chandigarh .You can also enquire us online for more info , or call us at +917087971455

  44. This blog is useful as well as informative. Keep sharing such blogs I really like your posts. top online fitness training course in india .

  45. Thank you For Sharing Your Useful Information with us! Book chandigarh to delhi taxi

Leave a Reply