PDA

View Full Version : gear ratio's


Warren
14-10-04, 06:29 PM
not sure where to post this . .. . so admin . feel free to move this (u prob would anyway :) )

seeing as 1st gear seems to be seperate from the other gears -
and recalling back from car driving days .
should you only use first to pull away then wack it into second as soon as you can , or am i ok driving in 1st (say about 20mph) ?
also - for optimum acceleration . . . . (i.e going fast on a straight) am i going to get more speed redlining it in first then going onto second.
or changing into second about 8k ?


just wondering - as when i change down from second to first- it seems so slow me more than from any other gear (i.e 3rd to 2nd)


just wondering . . . .

Jabba
14-10-04, 07:01 PM
Hmmm....................

There's a greater difference in %age terms between the ratios of 1st and 2nd than between 2nd and 3rd and so on. Your bike is no different to any other in that regard and, no different to your car for that matter.

It's OK to ride around in 1st if that's the best gear for the conditions or most appropriate gear for what you're doing at a given time.

Personally, I hang onto 1st gear for longer when pulling away in a straight line than I do when, for example, pulling out of a side road; I'll often snick into 2nd whilst manouvring/pulling out in that situation. I just feel a bit safer putting less power down in that situation, particularly on a wet road with cold tyres, and it gets the gear change out of the way earlier, meaning that I'm less likely to forget to cancel the indicators because I won't need to do two things in quick succession :roll:

It's only at the very top of the rev range (past peak power) where you will accelerate faster in a higher gear than a lower one. That part of the rev range will very-much depend upon your own bike's engine power curve and I can't guide you too much, although our bikes will be closer to each other (my Hornet has an engine from a 1998 CBR, suitably retuned :roll: ) than either will to an SV650.

I suggest that for fastest accelleration you will need to change up somewhere between peak-power and the red line.

HTH

Carsick
14-10-04, 09:38 PM
One point to bear in mind about redlining it. You won't get optimum acceleration if you push the revs that far since best part of the power will almost always be at lower revs. So, as Jabba says, change up somewhere in the part of the power band and you'll probably end up just a little into the lower end, ready to keep accelerating hard.

Warren
14-10-04, 09:40 PM
One point to bear in mind about redlining it. You won't get optimum acceleration if you push the revs that far since best part of the power will almost always be at lower revs. So, as Jabba says, change up somewhere in the part of the power band and you'll probably end up just a little into the lower end, ready to keep accelerating hard.

bearing in mind i have four barrels of hay .

Carsick
14-10-04, 09:51 PM
Granted, the power curve for your bike has the power band pushed very high up (here's an example http://www.motorcycle.com/mo/mccompare/01600/mcphotos/01cbr600f4idyno.html)
and I'm not entirely sure where the redline is. but if you look, the power drops off, gradually at first, then very steeply. Absolute optimum on that chart would probably be just under 14k (assuming that the chart was an accurate representation of the power output)
So, in other words, on your bike, pretty damn near red line is probably about right. On an SV, I think the best time is quite a bit lower.

Jelster
14-10-04, 10:29 PM
I've geared the Gixer down, just 1 tooth on the front, but it makes a big difference. It's much easier to keep up at around 10k and seeing as peak power is at 13,500 it's more fun to ride. It redlines at 15.5k and hits the limiter at 16,250.

As for 1st gear, bikes are not the same as cars, and 1st is a true "riding" gear, especially when you consider that I easily can do over 60mph in 1st :shock: I hardly ever use the clutch going up the box, and sometimes drop it down 1 without the clutch when I'm going to give it some berries :twisted:

.


.