Gear ratios

[clivegto]

I notice different sprocket sizes for gsxr 1100s b12s & 1100f. I presume they have different geabox ratios, does this make any difference to top end speeed on different engines in the same bike all using the same sprocket sizes.

[gsx]

Hi Clive , I use gearing commander, just Google it to find it .

You can input your bike and any wheel size changes  i.e. mines a slabby motor running 17 rear.

You can also put in different sprocket sizes and it works out top speed for you 

[Solcambs]

1 hour ago, clivegto said:

I notice different sprocket sizes for gsxr 1100s b12s & 1100f. I presume they have different geabox ratios, does this make any difference to top end speeed on different engines in the same bike all using the same sprocket sizes.

According to http://www.gearingcommander.com/

GSX1100F 88-94 has a Primary drive ratio of 1.522 and final drive gearing of 15-52

The GSXR1100 86-87 is 1.622 and 14-47, the 88 14-46, the 89, 90, 91 & 92 was 1.5652 15-48

The Bandit 1200 00-02 is 1.566 15-45

[Blue]

Any use? 

[Blue]

So am I right in saying a 15/45 has a ratio of 3:00 which is the same as 14/42?

[clivegto]

40 minutes ago, Blue said:

So am I right in saying a 15/45 has a ratio of 3:00 which is the same as 14/42?

That's what I was thinking but may be I am wrong.

[markfoggy]

I had a handy spreadsheet for this, that I used to use to get speeds in gears every time a new bike came along to go racing with.

The maths ain't difficult, if there is some demand I can build another one, could be a useful resource for the site.

But, what they said, Gearing Commander has all the data, so just use that. 

[markfoggy]

51 minutes ago, Blue said:

So am I right in saying a 15/45 has a ratio of 3:00 which is the same as 14/42?

Yes, but Much more important is the energy consumption, 14 tooth sprockets eat it for fun. Oh and destroy themselves pretty quickly.

16/48 is way more efficient.

[Gixer1460]

I tried explaining this to someone years ago who was hard of understanding - he swore blind his bike accelerated quicker with a 14/42 combo than 15/45 or a 17/51. My fav combo is 17/42 with turbo power - the 17 helps chain life, the turbo doesn't LOL!

[Ted M]

I have an Excel spreadsheet that calculates speed etc with different sprocket sizes I can let you have it if you want

[clivegto]

4 hours ago, Gixer1460 said:

My fav combo is 17/42 

Thats all good information, there won't be much room between the clutch push rod & the chain on a 17 tooth for t sprocket on a oil cooled motor is there ?

Edited April 7, 2017 by clivegto

[Oilyspanner]

A larger front sprocket is always best for chains, less abrupt changes of direction is easier on links - also a larger front s. reduces force acting on swing arm, more related to track set-upthan road though.

[Gixer1460]

2 hours ago, clivegto said:

Thats all good information, there won't be much room between the clutch push rod & the chain on a 17 tooth for t sprocket on a oil cooled motor is there ?

It clears - just........ I tried an 18 and not a chance!

[Solcambs]

2 hours ago, clivegto said:

there won't be much room between the clutch push rod & the chain on a 17 tooth

Correct .. IIRC 17 is about as high as you can go before the chain will saw through the clutch push rod.

[Solcambs]

3 hours ago, Ted M said:

I have an Excel spreadsheet that calculates speed etc with different sprocket sizes I can let you have it if you want

I used to have one of those ... but just use http://www.gearingcommander.com/  now. The site takes a few mins to get your head around, but you can have a standard, current, and new set up showing for the same bike, including changes to wheel size, chain pitch and it does it all for you. You can see shift points, and speed in each gear at redline.

Load a bikes standard set up, then mess with the settings to see the impact.