English diff ratios

[Tony B]

Steve, its is called CarTest, there are a couple of vesions floating around the old DOS version which I believe was Free and the Java version which isnt.. http://www.cartestsoftware.com/cartest2000/index.html

[Blatman]

There's definitely something missing from the calcs. I have a gearing calculator, into which I've input 5.1 diff, 215/40/16 tyre size, and an 11500rpm red line. The raw calculations give a max speed in first of 61mph.

The rest looks like this:

Gear   Mph per 1000 RPM   Mph @150 RPM   Mph @11500 RPM
--------------------------------------------------------
 1         5.31                           1                        61
 2         7.21                           1                        83
 3         8.85                           1                       102
 4         9.96                           1                       115
 5        11.07                           2                       127
 6        11.91                           2                       137

[timd]

What the primary reduction ratio?

There's a reduction in the gearbox after the gear ratios which you'll need to apply to all the specified ratios when you put them into cartest.

Here's some numbers from an old gearcalc spreadsheet - which might help..

Gear Ratio  Primary  1st      2nd     3rd     4th     5th     6th

ZX-9         1.714     2.571  1.941  1.556  1.333  1.200  1.095

ZX-12        1.596    2.428   1.823  1.440  1.250  1.130  1.033

98 blade   1.520     2.769   2.000  1.600  1.368  1.227  1.130

CBR1000   1.786     2.750   2.067  1.647  1.368  1.174  1.045

R1             1.465     2.600   1.842  1.500  1.333  1.200  1.115

If you alter all your ratios by the Primary number, your cartest results should make more sense - hopefully!

[Tony B]

obviously being very simple when you say alter all the numbers by the primary what do you mean - or /

[timd]

Sorry - multiply the specified gear ratios by the primary ratio and input the resulting numbers into cartest.