|
Author |
Message |
czakal |
This post is not being displayed .
|
czakal Nitrous Nuisance
Joined: 11 Apr 2011 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
Ben90 |
This post is not being displayed .
|
Ben90 Brolly Dolly
Joined: 06 Feb 2014 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
Teflon-Mike |
This post is not being displayed .
|
Teflon-Mike tl;dr
Joined: 01 Jun 2010 Karma :
|
Posted: 17:32 - 26 Feb 2017 Post subject: |
|
|
Almost all road bikes are 'over geared' in so much that the top gear ratio provides a top speed higher than peak power will allow.
Most 125's, without the amount of power bigger bikes have, tend to be far less over geared, and the top gear ratio fixed much closer to providing the top speed their power will allow.
Matter I suspect is somewhat mute, though, and I suspect that the missing link in what you recall from what your instructor was trying to tell you was "Use the Revs, not the gears"
Forget ratios'... little CG has a 10bhp engine, that is pretty linear in its delivery and power pretty proportional to engine revs, so if t's deverng 10bhp at 10,000 revs its it's delivering about 1bhp per 1000, so 1bhp at tickover, 2 at 2K, 3 at 3K, 4 at 4 etc.
Trouble is, that 'drag' increases in a ramp that's not linear. Takes around 3bhp to go 30mph, 9bhp to go 60, 27bhp to go 90.. ie to go 30mph faster takes 3x the power.
Little CG125, can make 3bhp with the throttle wide open, as low as 3ooo rpm, so go 30.... and it can probably do that in top gear... but try and accelerate.... if you go faster, engine can deliver more power, but takes more power to go faster than the power you get for it... so you have to change down, to get the engine up to revs where there's power to let you go faster.
And the trouble with little learner bikes, is that it seems counter intuatve to most learners to change down to go faster, and round town dong most learner exercises, usually on sub 40mph roads, very easy and feels more natural to short shift and use the higher gears, than to let the thing rev in the lower ones, ad that denies throttle response and a lot of potential 'control'.
Its not so much that the gearing is inherently too tall, it isn't. It's just that they don't have a lot of power, and learners who tend to try ridg them in too tall a gear, and doing too much work on the gears, changing up too much making work to change back down again. in their nievity and enthusiasm and ignorance, and little bikes don't have the excess to give them the flexibility to make then not so important. ____________________ My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?' |
|
Back to top |
|
You must be logged in to rate posts |
|
|
Rogerborg |
This post is not being displayed .
|
Rogerborg nimbA
Joined: 26 Oct 2010 Karma :
|
Posted: 18:42 - 26 Feb 2017 Post subject: |
|
|
Agreed, 5th gear on my 125 was pointless for top speed. It was only there to keep the revs down a bit on the flat or downhill.
The answer to any followup question is: get a licence, get a bigger bike. Even my Ninja 250 is far better, and the gearing is spot on for its top speed. ____________________ Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike |
|
Back to top |
|
You must be logged in to rate posts |
|
|
czakal |
This post is not being displayed .
|
czakal Nitrous Nuisance
Joined: 11 Apr 2011 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
Teflon-Mike |
This post is not being displayed .
|
Teflon-Mike tl;dr
Joined: 01 Jun 2010 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
czakal |
This post is not being displayed .
|
czakal Nitrous Nuisance
Joined: 11 Apr 2011 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
rhys99 |
This post is not being displayed .
|
rhys99 Scooby Slapper
Joined: 24 Feb 2015 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
czakal |
This post is not being displayed .
|
czakal Nitrous Nuisance
Joined: 11 Apr 2011 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
czakal |
This post is not being displayed .
|
czakal Nitrous Nuisance
Joined: 11 Apr 2011 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
mudcow007 |
This post is not being displayed .
|
mudcow007 World Chat Champion
Joined: 01 Feb 2012 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
rhys99 |
This post is not being displayed .
|
rhys99 Scooby Slapper
Joined: 24 Feb 2015 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
M.C |
This post is not being displayed .
|
M.C Super Spammer
Joined: 29 Sep 2015 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
kgm |
This post is not being displayed .
|
kgm World Chat Champion
Joined: 04 Jun 2015 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
mudcow007 |
This post is not being displayed .
|
mudcow007 World Chat Champion
Joined: 01 Feb 2012 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
kgm |
This post is not being displayed .
|
kgm World Chat Champion
Joined: 04 Jun 2015 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
Old Thread Alert!
The last post was made 7 years, 59 days ago. Instead of replying here, would creating a new thread be more useful? |
|
|
|