Harry's GPS Suite Forum

hello, i'm having an issue entering my motorcycle into the vehicle database. i will include screen shots and links to the info i know on the bike. basically when i enter the transmission info, i get inaccurate numbers.

using stock numbers of specs on my bike, this is what i find:

Max Power
117 hp 66 KW @ 13000 rpm (102 hp @ 13500 rpm)

Max Torque
66.6 Nm @ 11000 rpm

CBR600RR 03 04 Clutch system is Multi-plate and wet,
CBR600RR 03 04 Clutch operation system is Cable operating,
CBR600RR 03 04 Transmission is Constant mesh and 6-speeds,
CBR600RR 03 04 Primary reduction is 2.111 (76 / 36),
CBR600RR 03 04 Final reduction is 2.688 (43 / 16),
CBR600RR 03 04 Gear ratio 1st is 2.666 (32 / 12),
CBR600RR 03 04 Gear ratio 2nd is 1.937 (31 / 16),
CBR600RR 03 04 Gear ratio 3rd is 1.611 (29 / 18),
CBR600RR 03 04 Gear ratio 4th is 1.409 (31 / 22),
CBR600RR 03 04 Gear ratio 5th is 1.260 (29 / 23),
CBR600RR 03 04 Gear ratio 6th is 1.666 (28 / 24),

unfortunately my motorcycle is not stock, for now i have decreased one tooth on the front sprocket. in the future i will increase one or two teeth in the rear for different tracks so i would like to understand how to change the settings for the most accurate data in the laptimer app.

using http://www.gearingcommander.com/ , i input my gearing combination at the present to achieve this data: be sure to pay attention to the "current settings" in the pic for what combination i am running now.



i believe i have entered the correct info into the tables, i currently run 15/43 which is -1/stock. in the future i want to change to possibly -1/+1 or -1/+2, depending on what track i will be attending. i guess i am confused at the drive ratios and when i enter the info into the laptimer app i get this -





obviously the top speeds calculated in the last picture are inaccurate. does this affect the accuracy of my speeds logged during laps?
any help would be greatly appreciated, i can provide more pics or details of the bike if needed. 03 CBR600RR, full exhaust, aftermarket filter, weight reduction, stock motor and trans, 520 pitch chain kit.

Hi,

Let us first get the stock configuration correct:

CBR600RR 03 04 Primary reduction is 2.111 (76 / 36),
CBR600RR 03 04 Final reduction is 2.688 (43 / 16),
CBR600RR 03 04 Gear ratio 1st is 2.666 (32 / 12),
CBR600RR 03 04 Gear ratio 2nd is 1.937 (31 / 16),
CBR600RR 03 04 Gear ratio 3rd is 1.611 (29 / 18),
CBR600RR 03 04 Gear ratio 4th is 1.409 (31 / 22),
CBR600RR 03 04 Gear ratio 5th is 1.260 (29 / 23),
CBR600RR 03 04 Gear ratio 6th is 1.666 (28 / 24),

means you have a combined reduction from primary and final of 2.111 * 2.688 = 5.674. Enter this value into the 'Drive Ratio' field. Enter the gear ratios 1 to 6 into the respective gear ratio fields (#5 and #6 are wrong in the snapshots, leading to the 'undriveable' jumps from gear #4 to #5). Having this done, you should see a reasonable chart.

Now on your optimizations: if you reduce the number of sprockets by 1 (e.g. from 15 to 14), you need to multiply (or divide) the Drive Ratio by 14/15 = 0.9333. Wether you multiply or divide, depends on front or rear sprocket. You will most probably never change any of the gear ratios (except you open your gear box and start working here), it is almost always the overall ratio = Drive Ratio that is changed.

Hope that helps,

Harry

it makes total sense now! thank you so much. i was simply missing a step in my math equation. now i can just save different profiles of the same bike and choose which gearing i am running on that particular day. thanks a lot for your help, and i love the app!