Scooterotica

I've improved this little bit of software to help evaluate whether a Lambretta gearbox setup is suitable for it’s application, find a solution to gearing issues, or help design a setup to suit specific engine output characteristics.

This new version now gives a side by side comparative view so that you can enter your current setup in the left hand pane, and then have a play with ratios, sprockets and tyres dynamically in the right hand pane to see the difference.

There is also data on 5-Speed boxes, “dealer” close ratio boxes, extended tyre data including Dunlop TT92GP and SAVA MC20 for the racers. Special thanks to Ian Hepworth who provided data on Lambro and Lambretta small frame boxes.

It should be relatively intuitive, but feel free to use this thread for help or to highlight bugs.

To run this you need Excel or an equivalent (Openoffice is very good and is free).

It's all FREE so help yourself, I'd just ask people NOT to host it themselves on their own sites, but to link to mine so I can track usage.

Download here http://www.tonycassidy.com

good work once again. thanks
I can play with this all night

sweet work

Good work mate

thats good stuff, can you do one for vespa smaalframes as the one on scooter help doesnt have all the available variations

Great spreadsheet while using my computer at home, but doesn't work with Google Docs, parts missing etc. Can this be fixed Tony?

A response to a question on LCGB that maybe useful if you haven't got a dyno sheet.

bootros wrote:I've played around with the previous version quite a bit, very interesting thanks. How would you define the minimum usable revs?

Ideally you'd have a dyno sheet and would enter the RPM where the power/torque really starts to pick up.

Failing that, you can use an "arse-dyno". For instance assuming you've got a reasonable accurate speedo (stop laughing), pull away and get it straight into 3rd gear. Hold the throttle wide open and note the speed at which the engine starts to get hold of the gear. If you then feed your setup into the visualiser, adjust the "minimum" value until the bottom of the green bar in 3rd gear equals the speed you noted on the road - this will approximately be your minimum usable RPM.

Using the same methodology, your "maximum" RPM will equate to the speed in 3rd gear when your arse says it's no longer really accelerating hard, but just making lots of noise and will be the speed at which you'd naturaly feel was right to change up (I say use 3rd because 2nd is too low to feel what your after, and if you're over geared, 4th may be too high to actually hit the maximum.

Again using the same methodology, the red line is simply that. The maximum speed you can hit in 3rd beyond the point where you'd naturally want to change up.

Not particularly accurate, but you'll get an approximation.

It's at this point I suppose I should say be careful, and keep your eyes on the road

Hope this is (sort of) helpful............

jonny snatchsniffer wrote:thats good stuff, can you do one for vespa smaalframes as the one on scooter help doesnt have all the available variations

It's all just data so there's no reason why not

If someone can point me to the data, I'll build it...............

soulsurfer wrote:Great spreadsheet while using my computer at home, but doesn't work with Google Docs, parts missing etc. Can this be fixed Tony?

I'll take a look and find out why........

Thanks

Your previous version really helped me with my choice of Gearbox.

Tony

Brill modification m8 keep it going

Smiffy