Tire size effect speedometer?

[mrmike]

  My '23 People S150i ABS speedometer is 2 miles an hour off (higher) at all speeds. This fall I'm going to buy new Michelin City Grip 2 tires for better wet weather traction. If I replace the front 100/80-16 with a City Grip 120/80-16 what effect (if any) would it have on the speedometer

[Stig / Major Tom]

  My '23 People S150i ABS speedometer is 2 miles an hour off (higher) at all speeds. This fall I'm going to buy new Michelin City Grip 2 tires for better wet weather traction. If I replace the front 120/80-16 with a City Grip 120/80-16 what effect (if any) would it have on the speedometer

With your improved grip - you'll be able to spend more time looking at it..?
Do you ride much in the rain?....most folks don't. Ever.
Stig

[mrmike]

With your improved grip - you'll be able to spend more time looking at it..?
Do you ride much in the rain?....most folks don't. Ever.
Stig

  I don't plan on it Stig, but I'm finally riding more now. If I get caught, I want the best possible rain tires I can buy. Most folks think City Grip 2's are it. With those tires and my Frog Togs I'll feel much better if I do get caught. I'm just wondering what impact a bigger front tire would have on handling and my speedometer reading.

[Stig / Major Tom]

  I don't plan on it Stig, but I'm finally riding more now. If I get caught, I want the best possible rain tires I can buy. Most folks think City Grip 2's are it. With those tires and my Frog Togs I'll feel much better if I do get caught. I'm just wondering what impact a bigger front tire would have on handling and my speedometer reading.

A 120/80-16 City Grip will report on the speedo as did your 120/80-16 stock tire.
Perhaps you meant a different size Michelin?
Love my Frog Tog for 13 yrs now. Make decent over-pants too for my winter rides in Ohio.

Stig

[mrmike]

A 120/80-16 City Grip will report on the speedo as did your 120/80-16 stock tire.
Perhaps you meant a different size Michelin?
Love my Frog Tog for 13 yrs now. Make decent over-pants too for my winter rides in Ohio.

Stig

The stock tire is a 100/80-16. The City Grip 2 would be a 120/80-16. Just wondering if the different dimension would impact my speedo reading?

[rjs987]

The stock tire is a 100/80-16. The City Grip 2 would be a 120/80-16. Just wondering if the different dimension would impact my speedo reading?

In that case... The speedo will be closer to actual or possibly showing slower than actual with that much of a difference in size.
First number is width in mm at normal inflation and load. Second number is the percent of the first number for height of the tire from the rim/bead. OEM tire size is 100 mm wide by 80 mm tall on one side (100 x 80%). The intended new tire is 120 mm wide by 96 mm tall on one side (120 x 80%).



The difference in height of the tire between those 2 sizes would be 16 mm on one side. A bigger tire = less rotations = less mph indicated per actual speed.


BTW - you CAN modify your original post to correct the OEM tire size you mentioned by clicking on the word "Modify" at the top right of your post.

[Iahawk]

going from a 100 to 120 width is a fairly big jump. Any reason you're going for the increase? Will the larger tire fit or cause any clearance problems?

[Stig / Major Tom]

Always found this helpful......
No guesswork.

TIRE SIZE CALCULATOR
https://www.tacomaworld.com/tirecalc?tires=100-80r14-120-70r14

Stig