Speed help.

[DrunkenMistake]

And I mean I speed and I need help, I actually enjoy it

I have just put on a 14t front sprocket and a 42 rear sprocket, and obviously this is going to ruin my speedo, so what I want to know can someone give me some kind of calculation so I can figure out my Real speed, cheers.

[porndoguk]

you got a sat nav?

[Drunkn Munky]

There you go
http://www.gearingcommander.com/

[DrunkenMistake]

There you go
http://www.gearingcommander.com/

I have seen this,

im more after the % of difference the speedo will be out by so I can get a good reading.

I took it for a blip earlier and was reading 120km and im positive it was only about 90

[Drunkn Munky]

Your never have time to work out percentages whilst riding, plus it'll be different for each gear your in. Just get some form of GPS speedo, a digital one or just dont worry about it.

[DrunkenMistake]

Your never have time to work out percentages whilst riding, plus it'll be different for each gear your in. Just get some form of GPS speedo, a digital one or just dont worry about it.

Haha yah, I think the last time I actually done the speed limit was when I had stopped after been pulled over by the police..

[amorti]

Another suggestion:

Did you realise the little elbow gearbox in the back of the speedo can be used to alter the speedo calibration? Here's a picture of the inside of a cb-1 speedo to illustrate my point.


The yellow plastic gear on the back of this km/h speedo has 12 teeth. The matching yellow gear in the elbow has 11 teeth. Equivalent MPH speedos have 12:12 green plastic cogs. The reason is the km/h speedo comes from a JP bike which were sold with 15/41 gearing, while the mph speedo comes from a USA bike which were sold with 15/37 gearing. Changing these parts gives about a 9% reduction in speedo reading when compared with equivalent green-toothed parts, matching the regearing of the final ratio fairly closely.

It's not a very precise calibration, but the option is there. I have a spare gearbox with yellow 11:12 gears. I have no clue what's in an nc30, but if 11:12 is any use, then give me a shout. I find myself wondering what the equivalent conversion rates would be on any number of Hondas which use the same speedo, I am sure the same system was used on early Blades, many CBR600s, etc. etc.

Hope that makes sense and maybe helps!

[DrunkenMistake]

Another suggestion:

Did you realise the little elbow gearbox in the back of the speedo can be used to alter the speedo calibration? Here's a picture of the inside of a cb-1 speedo to illustrate my point.


The yellow gear on the back of this km/h speedo has 12 teeth. The matching yellow gear in the elbow has 11 teeth. This gives about a 9% reduction in speedo reading when compared with equivalent green-toothed parts from a mph speedo which have 12:12 teeth. The reason is the km/h speedo comes from a JP bike which were sold with 15/41 gearing, while the mph speedo comes from a USA bike which were sold with 15/37 gearing.

It's not a very precise calibration, but the option is there. I have a spare gearbox with yellow 11:12 gears. I have no clue what's in an nc30, but if 11:12 is any use, then give me a shout.

Hope that makes sense and maybe helps!

makes alot of sense actually, according to what you said I should have a 11:12, I have a straight Jap import in Km/h.
Ill have a look about, I may just end up getting my hands on someone GPS, I only need to know my read speed at 50km/h and the dial speed at that speed to work out a % of how far + or - the speedo is, then it should be the same % across the dial, all I have to do is put some markers on my speed so I know. 50 - 70 - 100km are the important numbers as 50km is the limit around town, and 70 is the limit on the road I have to take to get back home etc, and 100 for the open road.

[amorti]

In going from 15:40 to 14::42 you have done this:
(14:42) x (15:40) = 1/8 , so your speedo will be over-reading about +12.5%. That is, about 12.5% more than it was before, since we all know [bike] speedos over-read anyway.

The 11:12 gearbox will subtract 1/11 or 9.1% off your speedo reading, if yours normally has 12:12 gearing.

[amorti]

makes alot of sense actually, according to what you said I should have a 11:12, I have a straight Jap import in Km/h.
Ill have a look about, I may just end up getting my hands on someone GPS, I only need to know my read speed at 50km/h and the dial speed at that speed to work out a % of how far + or - the speedo is, then it should be the same % across the dial, all I have to do is put some markers on my speed so I know. 50 - 70 - 100km are the important numbers as 50km is the limit around town, and 70 is the limit on the road I have to take to get back home etc, and 100 for the open road.

My information is based solely on my research of CB-1s, I know nothing about nc30's! Have a look at the gearbox in your speedo and report back.