New gear ratio & recording 0-60 runs

[zetecy]

I bought a 2004 DT125 about 3 months ago and when i attempted to clean the chain i noticed how bloody tight/rigid it was. Having not seen an O-ring chain before i didnt know wheather this was slightly normal anyway.. I bout a Renthal R1 chain non oring and some pattern sprokets ( JT sprokets) from B&C express who where very good value and the postage was wooaahhh 2.55! next day, signed by royal mail. anyway i went for a 17 tooth front sproket instead of the standard 16 . reason being is that i find each gear on my bike seems to run out very quickly. using this awesome website i was able to model different sprokets and ratio's
https://www.cosportbikeclub.org/misc/SpeedCalc.html. luckily i had all the info needed from a workshop manual. so after my dad helping me install it i went for a test ride and instantly noticed a smoother ride and wasnt as jerky as before. i can just cruise better without having to shift too often. not too shore if it has affected my acceleration yet. I want to ask how other people have gone about recording their 0-60 times (if people do ) counting in my head is hard when watching the speedo, and the road! . my mate has a RS125 which i have dragged many times and my 1st and 2nd gear get my bike 2 lengths infront and then it will be close up to 50/60 and he will start pulling away slightly (this is with my old sprokets 16front) so with the new sproket 17 im hoping each of my gears should in theory have a few more mph to squeeze out. what you think bad move or good, cant wwait for a drag but i dont want to loose :p (who does!) hehe, whos going to win?

cheers

[ms51ves3]

Set up a video camera looking at your speedo, record it to 60mph, use video editing software to accurately go from 0-60, look at the times at the beginning (0mph) and end (60mph) and then work out the difference

[zetecy]

its mounting the camera thats the problem. ive got a mini DV camera but im not exacly going to duck tape it lol um i cant even do a tank cam because my speedo is in a weird position . imagine straping a camcorder to my helmet lol that would be rediculous

[ms51ves3]

How about strapping your phone to your helmet. A little more discreet.

[zetecy]

how do you recon this guy did his, i tried emailing him a while back but he didnt answer think hes french lol

https://uk.youtube.com/watch?v=vnIJ0XjyJEU

[ms51ves3]

If you look at the reflection in the clock it looks like it's in a paper bag. Maybe he taped it to his bike.

[Kickstart]

Hi

You speedo will not be accurate, so no chance of getting an accurate 0-60 time from a video of it (from memory speedo accuracy has to be within 10%+8kmh in production, so a speedo would be legitimate if it indicated 60mph while you were only doing 50mph).

Only real way to do it is with some decent performance measuring equipment. Cheapest is the Driftbox (GPS with a G meter as well) or the cheaper PerformanceBox (same unit but without the G meter).

While 1 tooth more will allow you to rev out further in each gear, it will also have less thrust in each gear. Whether you loose or gain will depend on how close the gear ratios are and how the power drops off.

Find the gear ratios and a dyno chart for you bike and put them in to this:-

https://www.bikegraph.co.uk/TorqueGraphs.php

(you need to be registered to put you own details in, but if you want then PM me and I will enter them).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[G]

Can get a decent push bike speedo and make them fairly accurate.
Something like the veypor units have in built functions to work out 0-60 and and standing quarter times, as well as approximations of power.

[zetecy]

I have tried to post message 4 times now and kept getting the server timeout message. so anoying i had wrote nearly an essay! anyway hope this one goes through but ill make it brief incase i loose it again!

- in the end i changed back to 16T . 17 was ok but there was a noticable decrease in acceleration and i didnt like it, it was almost not fun to ride anymore. 16T back on and its nice and snappy, ill just accept 125's wernt designed for huge speed. But yesterday night when i put the 16T back on i went for a test drive and undertook (moved into bus lane briefly) a car doing 25mph and had flashing lights 10 secs later . it was an unmarked merc GX54... i ended up geting a warning section 59 which was lucky could have been speeding ticket (ahh points!) . so watch out guys and hold back you urge to do abnormal things! unless you absolutely sure you can get away with it

[Welshd1k]

a dtr beating a rs125 ??? :S your mate cant be riding it hard, my ns125 is faster 0-60 than a dt125 full power and dep pipe and a rs125 eats my bike
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