Why gear down or up?

[baffa]

I notice a few people change the rear sprocket and gearing on their bikes. How common is it? And why?

I can see the appeal on a sports bike, enjoying the sweet sweet sound of an IL4 at redline is only possible at insane speeds. Apolagies to anyone who was woken up last night on a certain street on the shore, the throttle jammed I promise :sunny:

[wanpo]

I notice a few people change the rear sprocket and gearing on their bikes. How common is it? And why?

I can see the appeal on a sports bike, enjoying the sweet sweet sound of an IL4 at redline is only possible at insane speeds. Apolagies to anyone who was woken up last night on a certain street on the shore, the throttle jammed I promise :sunny:

Longer gears for fuel efficiency (lower revs = less petrol burned)

Shorter for acceleration, stunting, overcome lack of torque.

I imagine people big into racing would change (possibly either way) to escape being inbetween the sweet spots of two gears when you want to get on the gas mid-corner. (You want to be in the torque to get the drive out)

[george formby]

Standard gearing on tubby is 3800rpm @ 100kmh. The engine is not quite in it's sweet spot. 1 tooth down on the front is 4000 rpm (ish) @ 100 kmh. Right on the money stroke, more responsive, smoother & more fuel efficient. Smaller throttle opening for the same revs. That's my reason any hoo. It also means I can ride between 15 & 100+ kmh in third if I so desire, very handy on twisty roads.

[SMOKEU]

I went -1 on the front because the bike needs the shit revved out of it to go anywhere fast and has a big torque hole below about 4,000RPM due to the jetting.

[george formby]

I went -1 on the front because the bike needs the shit revved out of it to go anywhere fast and has a big torque hole below about 4,000RPM due to the jetting.

Jetted for performance or to get through noise emission regulations? My bike gets happy just above 4000rpm on standard jetting. A lot of bikes seem to have an ole about there in the rev range.

[DEATH_INC.]

-1 +1 on the 10. Makes it accelerate quicker. 170kph in first is a bit silly, tho it'll still do 160+. Makes it silly trying to keep the front tyre in contact with the road tho :devil2:

[javawocky]

I notice a few people change the rear sprocket and gearing on their bikes. How common is it? And why?

I can see the appeal on a sports bike, enjoying the sweet sweet sound of an IL4 at redline is only possible at insane speeds. Apolagies to anyone who was woken up last night on a certain street on the shore, the throttle jammed I promise :sunny:

I have never changed gearing but I can understand why someone would on the track.

Hampton Downs Turn 4 (The 90 slow right hander) up the hill towards the left hair pin. Second gear is just about perfect to give enough drive off the corner and closer to red line before the braking spot. I think If I were a faster rider I might adjust gearing a little to avoid a gear change.

Which reminds me how much I love an IL4 which a large rev range :)

[george formby]

-1 +1 on the 10. Makes it accelerate quicker. 170kph in first is a bit silly, tho it'll still do 160+. Makes it silly trying to keep the front tyre in contact with the road tho :devil2:

Ahh, to save money on tires?

[Kickaha]

and has a big torque hole below about 4,000RPM due to the jetting.

Then why don't you get it jetted correctly?

[SMOKEU]

Jetted for performance or to get through noise emission regulations? My bike gets happy just above 4000rpm on standard jetting. A lot of bikes seem to have an ole about there in the rev range.

Apparently it has a Yoshi MJN jet kit in it. The guys at the gixxer.com forums seem to think so as well from the description I've given them. I know it's not jetted to give low emissions as it does around 8L/100km on the open road when I'm not riding too hard. It's a 600 SRAD.


Then why don't you get it jetted correctly?

As above.

[Kickaha]

Apparently it has a Yoshi MJN jet kit in it.
That doesn't mean it's right

The guys at the gixxer.com forums seem to think so as well from the description I've given them.
Have any of them tried running one on a dyno to check one properly?

[SMOKEU]

Have any of them tried running one on a dyno to check one properly?

I'm not too sure. I'm not really that worried about it because it runs very well if I keep the revs above 4,000RPM, just gets fairly jerky and rough and feels like it's running rich at low revs. Still, better rich than lean.

Carbies have recently been stripped and balanced by a bike shop as well.

[nzvlogger]

Very helpfull going down 1 tooth on the front for a VFR400, itl do 120km in first standard but you got to ride the clutch with the standard cog at the lights. makes them feel much better low down.

[GrayWolf]

I went -1 on the front because the bike needs the shit revved out of it to go anywhere fast and has a big torque hole below about 14,000RPM due to the jetting.


there, fixed it for you

[SMOKEU]

there, fixed it for you

Redline is at 13,500RPM :clap:

[DEATH_INC.]

Ahh, to save money on tires?
Of course :msn-wink:

[GrayWolf]

I went -1 on the front because the bike needs the shit revved out of it to go anywhere fast and has a big torque hole below about 4,000RPM due to the jetting.


I went -1 on the front because the bike needs the shit revved out of it to go anywhere fast and has a big torque hole below about 14,000RPM due to the jetting. there, fixed it for you


Redline is at 13,500RPM :clap:

Yup, kinda just proved my point? :lol:

[Eddieb]

Yup, kinda just proved my point? :lol:

+2 teeth on the rear of my DR650. The standard gearing is a bit high for rough inclines when adventure riding, the change in gearing makes things much more managable in slow rough stuff.

[pritch]

I notice a few people change the rear sprocket and gearing on their bikes. How common is it? And why?


For road use it shouldn't be too common, the basic advice is "don't". Most bikes are fine as is.

As always though there are the exceptions, Ducati f'rinstance. Many people drop a tooth on the front sprocket of some models as it makes them easier to ride in town and in tight twisties.

Of all the bikes I've owned, the Ducati was the one time I bothered.

If you want to drop more than one tooth on the front sprocket it can cause the chain to be at too acute an angle so in most cases it is preferable to go up the appropriate number of teeth on the back sprocket instead.

[DEATH_INC.]

I know quite a few that have done it for the road. Most bikes are geared for stoopid speeds, so a bit of down-gearing improves acceleration, which you use way more than top speed.

[tigertim20]

DM on here regeared his NC30, he used it as a commuter, but his commute was along my favourite windy piece of coastal road, he reckoned it made it much better through town, and liked the extra punch out of corners.

I know alot of people on litre bikes regear it for the extra torque - some reckon its the most cost effective way to increase performance. i guess that depends how you define performance and how you like to ride.

[Gremlin]

Went -1 on the front of the KTM 990 SM. Couldn't use 6th unless you were doing 130kph+, which was ridiculous, and 6th was very economical. After the change in gearing and some re-tuning I could manage 120kph in 6th, a bit better.

Sadly, it meant power wheelies in 3rd as well as 1st and 2nd... what a shame :lol:

[DrunkenMistake]

DM on here regeared his NC30, he used it as a commuter, but his commute was along my favourite windy piece of coastal road, he reckoned it made it much better through town, and liked the extra punch out of corners.

I know alot of people on litre bikes regear it for the extra torque - some reckon its the most cost effective way to increase performance. i guess that depends how you define performance and how you like to ride.


The standard NC30 set up made first gear super tall, I think off my head you could do close to 80km? I think Im wrong there, but for some reason it seems right
Either way having such a tall gear in traffic was rough as nails, and having a top speed of 180 - 200 is pretty pointless when doing a 15km commute daily and the occasional balls to the wall ride, so gearing it to top out at about 160 - 175 seemed to be the sweet spot, heaps of bunch and utilised almost all the gears.

[98tls]

Have had +2 on the TL for years,makes a lazy V-twin do some work.:banana:

[koba]

The standard NC30 set up made first gear super tall, I think off my head you could do close to 80km? I think Im wrong there, but for some reason it seems right
Either way having such a tall gear in traffic was rough as nails, and having a top speed of 180 - 200 is pretty pointless when doing a 15km commute daily and the occasional balls to the wall ride, so gearing it to top out at about 160 - 175 seemed to be the sweet spot, heaps of bunch and utilised almost all the gears.

Lots of bikes like that actually run faster top speed times with LOWER gearing too... 'scoz they can't quite pull top hard enough.