ok soo im new to the hole bike thing only had mine for about 5 months now & yes ive researched & get mixed answers ive heard you take the rear sprocket devided by the front & it gets your "final drive" to say soo -1 down 2 up would be a shorter gearing would that make your mph diffrent??? cuz ive also been told thats it cancles its self out im lost haha i did -1 2+ & my first gear still bounce the rev limit at 71 mph but do feel faster i stretched it also if that makes a diffrent plz do dont bash on being stretched some like on there knees on one wheel but i like going straight thanks guys

 

Dude your speedo stays the same because the sensor is on the front sproket not the wheel. Your REAL speed per RPM goes down, but indicated speed per RPM stays the same. And no -1 +2 doesn't cancel out. -1 in the front is about +5 in the back depending on what bike you have, and that isn't enough for a sub 1000cc imo, so you add the extra 2 teeth out back to give you what is essentially +7.

 

IIRC, the speedo reads higher from the lower gearing unless it is reading off the front wheel.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chris y0! &raquo;</TD></TR><TR><TD CLASS="quote"> -1 in the front is about +5 in the back depending on what bike you have.</TD></TR></TABLE>

Correction -1 in the front is about +2 to 3 in the rear regardless of what bike you have. It just rule of thumb.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by marmaladeboy &raquo;</TD></TR><TR><TD CLASS="quote">IIRC, the speedo reads higher from the lower gearing unless it is reading off the front wheel.</TD></TR></TABLE>

+1

 

agreed, -1 in the front is like having +2-3 in the back. So you've got around +4-5 total final drive increase. Don't bother figuring out your actual final drive, there's no real point.
If your bike's speedo runs off the front wheel then the speedo won't have changed. If it doesn't then you're speedo isn't going to read correclty and you need a speedo healer.
If you feel the difference what's the problem?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ACRProject &raquo;</TD></TR><TR><TD CLASS="quote">

Correction -1 in the front is about +2 to 3 in the rear regardless of what bike you have. It just rule of thumb. </TD></TR></TABLE>

Well technically youre wrong. It actually very much depends on your bike. Say your bike has 15 front and 45 rear, that means taking one off the front is equivalent to +3 on the rear because 45/15 = 3. But if your bike has something like 15/30 (for some reason, but each bike is different) then reducing one of the front is only equal to +2 on the rear because 30/15 = 2.

But you are correct in that the rule of thumb is usually +3.

To the OP:
Most likely youre speedo is going to read a higher speed than you are going because of the reduced final drive. However some bikes read their speed off the front, in which case youre speedo will remain the same.

 

ok well my stock is 15=40 but i thought if you shorten your final drive the mph would be lower kinda like on my car i went from a 4.4 to a 4.7 & it was deff. lower mph in every gear... i am now 14-42 but first gear still bounces rev limiter at 71 mph or is more like a crank pulley & alt. pully make one smaller & bigger & it just frees up HP & moves hp to a diffrent rpm sor to say???

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NABeastRR &raquo;</TD></TR><TR><TD CLASS="quote">ok well my stock is 15=40 but i thought if you shorten your final drive the mph would be lower kinda like on my car i went from a 4.4 to a 4.7 & it was deff. lower mph in every gear... i am now 14-42 but first gear still bounces rev limiter at 71 mph or is more like a crank pulley & alt. pully make one smaller & bigger & it just frees up HP & moves hp to a diffrent rpm sor to say???</TD></TR></TABLE>

Holy ****...learn to use some punctuation

 

hahaokilltrytoremeberthatnexttimeforyou thanks for your big help quiks66

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NABeastRR &raquo;</TD></TR><TR><TD CLASS="quote">but first gear still bounces rev limiter at 71 mph</TD></TR></TABLE>

Dumbass, you're not really going 71mph.

Newer bikes = electronic speedo signal to the dash, it doesnt really know what speed the wheels are going, just what the wheels should be going at based on the speed of the transmission's output shaft.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">

Dumbass, you're not really going 71mph.

Newer bikes = electronic speedo signal to the dash, it doesnt really know what speed the wheels are going, just what the wheels should be going at based on the speed of the transmission's output shaft.</TD></TR></TABLE>

But theoretically on a stock bike it would be a correct reading, no?

 

ok thanks ******** i said i was new to bikes & didnt know much just looking for help

 

they speak english in what?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">

Dumbass, you're not really going 71mph.

Newer bikes = electronic speedo signal to the dash, it doesnt really know what speed the wheels are going, just what the wheels should be going at based on the speed of the transmission's output shaft.</TD></TR></TABLE>

.RJ loves the shaft.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NABeastRR &raquo;</TD></TR><TR><TD CLASS="quote">ok well my stock is 15=40 but i thought if you shorten your final drive the mph would be lower kinda like on my car i went from a 4.4 to a 4.7 & it was deff. lower mph in every gear... i am now 14-42 but first gear still bounces rev limiter at 71 mph or is more like a crank pulley & alt. pully make one smaller & bigger & it just frees up HP & moves hp to a diffrent rpm sor to say???</TD></TR></TABLE>

First, a 4.4 to a 4.7 would effectively shorten your final drive, and make the bike faster. You would notice that the top speed of ever gear is lower because you shortened your final drive. If first gear usually tops out at 50mph and you shortened the FD it would now be something lower like 40mph or something.
The same is true on your bike.
But if your speedo is running off the transmission it still thinks 8k rpms means 40mph in X gear. That will never change unless you get a speedo healer. If it runs off the front wheel, you're fine.

The stock speedo is inaccurate. Unless you own a honda. Honda's speedos have been tested to be almost 100% accurate, along with their tachometers.
My SV's speedo is 10% off. If i get a 70 series front tire instead of my 60 it will effectively fix that.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GOD &raquo;</TD></TR><TR><TD CLASS="quote">

.RJ loves the shaft.</TD></TR></TABLE>

&lt;3

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rdblckSV650S &raquo;</TD></TR><TR><TD CLASS="quote">

First, a 4.4 to a 4.7 would effectively shorten your final drive, and make the bike faster. You would notice that the top speed of ever gear is lower because you shortened your final drive. If first gear usually tops out at 50mph and you shortened the FD it would now be something lower like 40mph or something.
The same is true on your bike.
But if your speedo is running off the transmission it still thinks 8k rpms means 40mph in X gear. That will never change unless you get a speedo healer. If it runs off the front wheel, you're fine.

The stock speedo is inaccurate. Unless you own a honda. Honda's speedos have been tested to be almost 100% accurate, along with their tachometers.
My SV's speedo is 10% off. If i get a 70 series front tire instead of my 60 it will effectively fix that.</TD></TR></TABLE>

thanks for your help i understand a bit better now