4 replies to this topic

[Gsybeach]

I have a race-spec hayabusa mini with 13 tooth front and 40 tooth rear sprocket (standard Zcars setup).

I have been consistently doing 12.6 second quarter mile sprints reaching exactly 100mph at the finish line (only in 5th gear).

Does anyone know how I can work out if this is the optimum setup? Has anyone tried different sprockets?

I am tempted to try changing the rear sprocket for 38 tooth to gain more top speed but would this make it too slow off the line?

Attached Files

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[cptkirk]

Tasty bit of driving in the attachment there.......

Sorry cant be of any help on the sprocket issue but would like to know the outcome for my next project, keep us posted....

[Gsybeach]

Sadly it wasn't as tasty (or controlled) as it looks!
I'll keep you posted.

[R1mini]

What size are your wheels and tyres, and also what your redline is, that will give you the top speed and from that work out whether the gearing is under/over geared or about right

Cheers
David

[Gsybeach]

Ok, I was bored so I've made an excel calculation spreadsheet where you can change any of the values in red (ratios/wheel size/rpm) and it will give you your speed in each gear. Currently has Busa info but could be changed for other motors.

Although I've worked out speeds in each gear that doesn't tell me what would be the optimum for a 1/4 mile sprint. ie - would you be better to gear it low, say 110mph for max accelaration or high - 130mph for max top speed? Which one would get you to the line quicker?
I'm not sure if that one can be calculated! Any other ideas?

PS. I just tried to upload my spreadsheet but this site does not let you upload excel. If anyone wants a copy let me know and I'll email it.