How do I work out theoretical rear wheel revolutions?

[the_lone_wolf]

Originally Posted by stuartyboy

I've edited out all my posts on this thread because of Lone wolf. I don't want to be associated with or debate anything this guy says.

A PM was sent to him and that should have remained private. Instead he publishes the pm on the open forum - totally out of order.

funny, i thought sending someone an arsey pm when you realise you were wrong was just asking to get burned, seeing as i've nothing to hide from the public i'll just post a response here: there was nothing private about your message other than the fact that you were embarrassed to admit defeat on an open forum after getting yourself in so deep. get over yourself, you'll live, everyone makes mistakes and if you'd just said "oh yes, my bad" and not got an attitude on then i'd have left it alone and it would never have ended like this

still... "mods have been informed" so i guess this thread will disappear soon enough or posts will go missing, seems that editing out all your ones is a good start, most of them are still in my quotes regardless, and the full thread i saved last night will be fun, i can look back and have a laugh when i've nothing better to do

see you in the next argument

I suggest pistols at 20 paces should sort this one out like men!!?!?!

Seriously though, this has got a little out of hand. Egos down boys!!

The theory is actually very basic ... we know 3 things, wheel circumferance, gear ratios and RPM ... the rest is just conversions (e.g. KM to Miles, mins to hours) and multiplying ratios ... there is no need to wave 'Bronze Swimming cirtificates' about and get all 'tetchy' boys!!!

[the_lone_wolf]

Originally Posted by Blue_SV650S

I suggest pistols at 20 paces should sort this one out like men!!?!?!

Seriously though, this has got a little out of hand. Egos down boys!!

The theory is actually very basic ... we know 3 things, wheel circumferance, gear ratios and RPM ... the rest is just conversions (e.g. KM to Miles, mins to hours) and multiplying ratios ... there is no need to wave 'Bronze Swimming cirtificates' about and get all 'tetchy' boys!!!

i'll have you know i won the 25m race in primary school. sir; i challenge you to a duel



agreed this has got out of hand, but it wouldn't have if it wasn't so amusing to wind people up who take things too seriously - the theory is indeed pretty basic...

anyway, any chance of seeing the source code of your speed/gear/rpm calculator? i might dig out VB and see if i can figure it out

Well if you like … I could give you the source, but most of it concerns the GUI and reading default ratios from a file (this makes it easy to make a ‘flavor’ of my calculator for different bikes gearboxes without entering the code, just change the input file ) … anyway, the only bit you are concerned with would be the actual calculations function. So this is the fundamental maths/calculations behind it all!!! in Pseudo code format, with comments (depicted by/started with a ‘ ):-

‘If wheel was turning at engine speed, with wheel circumference in cm; work out distance that would be traveled in miles per hour
SpeedCalculationWithoutReduction = ((WheelCircumfarance/100000) * (RPM * 60)) * 0.621371) 'Circumferance in KM, Revvs per hour, KM to Miles

‘ now work out reductions:-

Reductions = primaryreduction * gearratio * (rearsprocket / frontsprocket) ‘gearratio is the gearbox reduction e.g. from the specs, 6th is 23/27 (0.851), primaryreduction is also from specs

‘ Now reduce the wheel speed using the calculated overall reductions:-

SpeedInGearAtRPM = SpeedCalculationWithoutReduction / Reductions


‘ Here are the gear ratios for SV650:-
‘Pimary - 2.088 (71/34)
‘1st - 2.461 (32/13)
‘2nd - 1.777 (32/18 )
‘3rd - 1.380 (29/21)
‘4th - 1.125 (27/24)
‘5th - 0.961 (25/26)
‘6th - 0.851 (23/27)

‘Standard sprockets for an SVS 44rear 15front

So a worked example:-
Input:-
200cm circumference, 10500rpm, 6th gear, 15t Front, 44t Rear.

SpeedCalculationWithoutReduction = ((200/100000) * (10500 * 60)) * 0.621371) = 782.9275
Reductions = (71/34) * (23/27) * (44 / 15) = 5.21801
SpeedInGearAtRPM = 782.9275/5.21801 = 150.0433

i.e. at 10500 in top with a 2m circumference rear tyre, you would theoretically be doing 150.0433mph!!!

Clear??

Note: presuming the variables are populated, the 3 lines of code in BOLD is all you need to do the calculations ... I made this into a little function and then set up a loop to feed in different values for the variables, reading them from the text boxes ... its all good clean fun and time better spent* than looking at mucky pictures of Angelina Jolie!!

*well more productivly spent!!

Wow! Just discovered that I missed all the excitement. Never thought
bikers could be so passionate about maths.

No idea who's right about the geeky stuff. But if I were to play devils advocate I'd have to say that you were wrong to post the PMs. Private is private. I would not be happy if someone did that to me. Your last post doesn't do you any favours and if you read it back you'll see why. Sorry and pls don't have a go at me its just the way it looks.

I've followed the whole thing via the thread subscriptions emails. I've not followed the maths, nor who's right and wrong. It's actually kinda nice to see people be passionate about something. Life isn't all roses. I don't think this has decended into a personal slanging match (and hope it doesn't) but it has provided entertainment, which I think means all posts have added value.

[the_lone_wolf]

Originally Posted by ninjadoll

Sorry and pls don't have a go at me its just the way it looks.

why would i have a go at you? you're being polite and i'm not going to say you can't have an opinion on something

that said if someone sends me a bitchy private message simply to get their parting shot in without anyone else seeing how they act when the public forum isn't watching i've no problem posting a response in public and taking the mick out of them, if you don't think that's right then that's cool, just remember not to send me bitchy PMs and keep your insults where people can see them - if i were to send you a message in private now with an attitude i'd not be surprised to see a response from you here taking me down a peg

anyway, Blue_SV650S; i'll have to look at that when i have a spare moment or two, i can't see why i'd have an issue with the actual coding as it's all simple math functions, the input files for each bike are a nice touch

Originally Posted by ninjadoll

No idea who's right about the geeky stuff. But if I were to play devils advocate I'd have to say that you were wrong to post the PMs. Private is private. I would not be happy if someone did that to me. Your last post doesn't do you any favours and if you read it back you'll see why. Sorry and pls don't have a go at me its just the way it looks.

Oh my, a finger in every pie tonight ninjadoll ... 'once you pop you can't stop' hey??!?!!?

So will be any of all this help HRC mechanic make my bike catch Casey in Mugello this weekend?