Assuming your speedo read accurately before the change, changing to a 15T will make the speedo reading be about 7% lower than actual speed.
A Speedo Healer would fix that, part # SH-V4 + SH-U01
Front sprocket change will my speedometer be off?
So I am a new rider, as far as a street bike goes. Been riding dirt bikes all my life on and off the street along with some dual sports (DRZ400). I just recently purchased the 2015 yamaha r3 and i friken love it. I can't stop riding. Only owned it for a week now and have put 320 miles on it with only 3 actual days of riding. I can't get enough of that bike. Now let me get to the point (sorry). I recently went on a ride with a friend up to evergreen colorado and on the highway i noticed the bike was doing 8500 RPM's at 75. That seems like a little more than i want because this bike is going to see a decent amount of highway riding between nebraska and colorado visiting family. So i decided to change the front sprocket up to a 15T. So far so good. Only concern is that my speedo is off. But here is where i am confused... 99% of the time gearing or tire size is changed the speedo is off... I had my girlfriend go ahead of me and set her car on cruise control at several speeds (30, 50, 55 MPH) and i never noticed a speedo change and i was right there with her... is it possible that the speedo is unaltered? if so how?
Thanks guys!
Thanks guys!
1 - 14 of 14 Posts
A Speedo Healer would fix that, part # SH-V4 + SH-U01
Thanks Fang! I'll have to check that out. If I'm not mistaken I saw you also own an r3. How are you liking the bike so far? Any ideas for essential mods?
I like the R3 a lot but I haven't had much time to ride it this Summer. I'm still doing mods to it. Almost done. Waiting for a couple more things to be released including mirror spacers, a Luimoto seat cover set and PUIG fork sliders. I have another 9 items on the way.Thanks Fang! I'll have to check that out. If I'm not mistaken I saw you also own an r3. How are you liking the bike so far? Any ideas for essential mods?
You can see most of what I've done so far in my old posts here:
http://www.r3-forums.com/forum/481-yzf-r3-pictures/5497-my-r3-mods-so-far-part-1-a.html
http://www.r3-forums.com/forum/481-yzf-r3-pictures/5505-my-r3-mods-so-far-part-2-a.html
http://www.r3-forums.com/forum/481-yzf-r3-pictures/8689-my-r3-mods-so-far-part-3-a.html
I'm working on Part 4.
Also see:
http://www.r3-forums.com/forum/546-...alled-sp-tadao-power-box-lite-slip-today.html
What is your RPM with the new sprocket?
Those are some good looking mods... im gonna have to grab a couple of those off of ebay. especially those rearsets and adjustable brake levers.I like the R3 a lot but I haven't had much time to ride it this Summer. I'm still doing mods to it. Almost done. Waiting for a couple more things to be released including mirror spacers, a Luimoto seat cover set and PUIG fork sliders. I have another 9 items on the way.
You can see most of what I've done so far in my old posts here:
http://www.r3-forums.com/forum/481-yzf-r3-pictures/5497-my-r3-mods-so-far-part-1-a.html
http://www.r3-forums.com/forum/481-yzf-r3-pictures/5505-my-r3-mods-so-far-part-2-a.html
http://www.r3-forums.com/forum/481-yzf-r3-pictures/8689-my-r3-mods-so-far-part-3-a.html
I'm working on Part 4.
Also see:
http://www.r3-forums.com/forum/546-...alled-sp-tadao-power-box-lite-slip-today.html
Unfortunately i dont know yet. Im currently out of town, i originally replaced the sprocket so i could ride it to nebraska where i am now but the thought occured to me that once i get here there is about 10 miles of dirt riding i would have to do. Unfortunately nobody with a truck and ramps was available so i left my poor bike in Colorado. I will let you know here in about a week or so. Ill also calculate the 7% off of the speedometer to let you know true MPH and RPM.What is your RPM with the new sprocket?
The only thing im concerned about (and it may be because im new and not used to it) is the noise my bike makes when shifting, that i dont think was that loud before the sprocket change. When i shift its a pretty loud bang in the gearbox. Not really sure about that. Any ideas on how to check if im somehow destroying my gearbox?
Most of these newer bikes read the teeth on the output sprocket. Therefore, if you change the front sprocket, the engine will turn slower, but speedo will still read properly. When you changed the sprocket, if you noticed a tubular "thingy" pointing at the sprocket - that is a sensor.So I am a new rider, as far as a street bike goes. Been riding dirt bikes all my life on and off the street along with some dual sports (DRZ400). I just recently purchased the 2015 yamaha r3 and i friken love it. I can't stop riding. Only owned it for a week now and have put 320 miles on it with only 3 actual days of riding. I can't get enough of that bike. Now let me get to the point (sorry). I recently went on a ride with a friend up to evergreen colorado and on the highway i noticed the bike was doing 8500 RPM's at 75. That seems like a little more than i want because this bike is going to see a decent amount of highway riding between nebraska and colorado visiting family. So i decided to change the front sprocket up to a 15T. So far so good. Only concern is that my speedo is off. But here is where i am confused... 99% of the time gearing or tire size is changed the speedo is off... I had my girlfriend go ahead of me and set her car on cruise control at several speeds (30, 50, 55 MPH) and i never noticed a speedo change and i was right there with her... is it possible that the speedo is unaltered? if so how?
Thanks guys!
Most of these newer bikes read the teeth on the output sprocket. Therefore, if you change the front sprocket, the engine will turn slower, but speedo will still read properly. When you changed the sprocket, if you noticed a tubular "thingy" pointing at the sprocket - that is a sensor.So I am a new rider, as far as a street bike goes. Been riding dirt bikes all my life on and off the street along with some dual sports (DRZ400). I just recently purchased the 2015 yamaha r3 and i friken love it. I can't stop riding. Only owned it for a week now and have put 320 miles on it with only 3 actual days of riding. I can't get enough of that bike. Now let me get to the point (sorry). I recently went on a ride with a friend up to evergreen colorado and on the highway i noticed the bike was doing 8500 RPM's at 75. That seems like a little more than i want because this bike is going to see a decent amount of highway riding between nebraska and colorado visiting family. So i decided to change the front sprocket up to a 15T. So far so good. Only concern is that my speedo is off. But here is where i am confused... 99% of the time gearing or tire size is changed the speedo is off... I had my girlfriend go ahead of me and set her car on cruise control at several speeds (30, 50, 55 MPH) and i never noticed a speedo change and i was right there with her... is it possible that the speedo is unaltered? if so how?
Thanks guys!
Gearing up will make your speedo more correct.
So save money
They are always up to 10% optimistic by law, never the other way.
So save money
They are always up to 10% optimistic by law, never the other way.
If changing the front sprocket "up", this would not apply if the speed is read electronically from a sensor "counting" the teeth in the front sprocket. Only the RPM's would drop at indicated speed. However, it would apply if you dropped a tooth or two from the rear - then the bike actual speed will be a little faster while the indicated speed would be the same.Gearing up will make your speedo more correct.
So save money
They are always up to 10% optimistic by law, never the other way.
Front or rear sprocket changes require a speed healer to make your speedo accurate. Wished they were still driven by the front wheel
I used the GPS on my bike, and here's what I saw.They are always up to 10% optimistic by law, never the other way.
37 indicated -> 36 gps
71 indicated -> 69 gps
So, like 2.5-3.5% error optimistic. I have 2 gps, and one reads about 0.5 mph faster than the other, so this still an estimation, but it's definitely not 10% like my Ninja which is horribly optimistic.
it's not counting teeth on the front sprocket, lol. Either sprocket will affect the read-out.If changing the front sprocket "up", this would not apply if the speed is read electronically from a sensor "counting" the teeth in the front sprocket.
Thanks!A Speedo Healer would fix that, part # SH-V4 + SH-U01
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