Sprockets, sizes vs gearing

[MikeH]

OK just been checking out some sites for chain and sprocket prices and I've noticed that the KLE and some of it's cousins have some different sizes depending on the year. As mine struggles to get to the red line 5th let alone in top I was wondering about using a larger rear off a newer bike.

The older models (mine) use a 16t front 44t rear while the newer Cat'd less powerful models use a 17t front and 46t rear

Now to add to the scenario the ER-5 (same engine but different box see below) had a 17t/42t and the early more powerful GPZ 16t/42t.

So what's the best, I have a '93 KLE500 but it does have an ER5 engine and box which is different to the KLE's original as the gear selection mechanism is opposite so I have a direct lever rather than the normal linkage. This could mean the ratios in the box are different explaining why the top end is a bit low.

Anyway I'm waffling, what I want to know is it worth going for a 46t rear as opposed to a 44t ? or up the front 1 or do both ? is there any magic formula to work out the effects on gearing ?

Cheers

Mike



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Busa Junkie

[G]

Various people have made stuff to do this (think Maurice has one on his site?)

You need to find the ratios of each one and compare them, so:

Say a top speed of 100mph
15/45 -> 14/47

15/45=0.33333
14/47=0.29787
0.29787/0.3333=.8937
100mph x 0.8937 = 89mph

So you start with 15/45 gearing, go -1/+2.
This gives you a reduction of 89%, so about 11% off the top speed.

[bish777]

do you have the 17t ER5 sprock on there?

If so just ditch it for a 16t one, that should make the bike more lively.

If you start adding teeth on the back youll prolly need to look at buying a longer chain.
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GSXR1100J

[G]

[MikeH]

The chain is about shafted so now is the best time for me to pratt about with sprockets before I lay out some serious wad on a decent chain set.

I'll get a 16t front first as they're dirt cheap and see how that goes with the standard 44t on the backend, I can always swop the rear if it still needs more.

As it is the red line is 11K with full power at 8.5K the bike won't pull more than about 9K in 5th (90ish) and then in 6th it hovers around the 8.5 to 9k (about a ton) unless you get it on a motorway and it will creep upto a ton five with enough room and a following wind.

As for wheelies, don't ask

Mike
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Busa Junkie

[MikeH]

Just checked the KLE and it has got a 17t ER5 sprocket on there which explains why it feels overgeared.

I've just been having a look at dirtbikestore.com I can get anything from a 13 to a 17 upfront so I might order a 15 aswell as the standard 16 to try it out, I've still got loads of adjustment on the swingarm so should be OK for chain length for the shortterm until I can find the right setup for it.

Also found this nice little calculator program

Mike
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Busa Junkie

[G]

[bish777]

I dropped a tooth off the front on my old XBR500, and it could rev out in top. went from just being able to crack 105 to hitting with a reasonable head of steam.
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GSXR1100J

[LUXY DJ]

G as you seem to know alot about it

iv gone from std gixer srad sprockets to 15 front & 48 rear renthals

so whats the % on that then?

i assume my acceleration is gonna be RAW which is what i want but HOW raw as i havent tried it out yet caue im waiting on sprocket cover


& my setup man said he can still get my bike to still get near its top end speed with the down geared setup

which i aint bothered about losing abit as i use more accel then the topend 150 odd
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GSXR750
(FAR FAR from standard) www.gixerjunkies.net

[G]

[LUXY DJ]

old chain came SO lose that it flung off & somehow whack & smashed the cover & smashed the water pump housing & coolant pissed out everywere yet The chain DIDNT break so got another water pump housing & C&S & now waiting for the sprocket cover as it NEEDS to be there cause the clutch cable & sensor go on/through it so yea it reads from the front sprocket iv been told i can get a correcter of some sort though


only dodgy thing is these screw-type things came out when i removed the water pump & asked on net checked diagrams online got a SRAD haynes manual & it dont have it in either so im baffled as to were they came from but it runs fine without them there kinda got thread on 1 end & go more pointed down other end with slight ripple bits like a pipe slides over/on them & they have a hole going through from 1 end to other end & 1 is SLIGHTLY fatter then the other but couldnt find anywere they go any ideas?

heres some pics(not focused tho cause it wouldnt)

https://img.photobucket.com/albums/v232/DJLUX/b390da53.jpg
https://img.photobucket.com/albums/v232/DJLUX/2d59960d.jpg
https://img.photobucket.com/albums/v232/DJLUX/b8aa968a.jpg
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GSXR750
(FAR FAR from standard) www.gixerjunkies.net