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Discussion Starter #1
My apologies for another gearing post.
Over the summer holidays I will be replacing the chain and sprocket on my 95 speed triple. I have all the parts and intend going down 1 tooth on the rear sprocket from 43 to 42. Its currently running the standard 17/43 set. This is a small increase in gearing but I am looking for the engine to be less busy at highway speeds. This year I had the tacho rebuilt by an instrument specialist and it now works all of the time instead of occasionally or only at high revs. I am still suspicious of the reading though and want to know if anyone has a standard gearing chart for the standard 5-speed gearbox. Currently my tacho says 3500 rpm at 110Kms/hour (68 mph). I need to know if this is about right – seems a bit low to me.

Any help in pointing me in the right direction for a gearing chart or advice re your tacho reading at 110kmh (68 mph) would be greatfully received.

Cheers from Blenheim NZ - KiwiGeoff
 

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Your tach reading seems to be about a thousand rpm low at that speed, relying on memory. There are formulas out there to help you with the math.

Are you sure that you want to put a 42 on the rear? You might have to slip the clutch a bit to get underway, especially if you ever travel with a load. I went the other way (45t) and love it but I travel with loaded luggage or a pillion about half the time. The other half I ride like a juvenile so it works either way.
 

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at 70, I think mine hums at about 4800 rpm, 85 mph/6K if I remember correctly. I guess I should double check and see what # of teeth I have on the rear, or it won't be much help.
 

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Discussion Starter #7
Thanks for the responses,

Both Denny and Lushy have pointed me in the right direction for gearing calculators.

Sailfish - the table confirm that my tacho though "fixed" and working is reading about a grand short at 110 kph. Not sure if there is a calibration adjustment but will look into that. Going from 43 to 42 teeth on the rear sprocket is not that greater change (about 2.5%) or about 100 RPM at 110 kph. I figure I can change the rear back again if needed - less hassle than the countershaft sprocket.

Long Road Home - your numbers check out to standard gearing.

Appreciate the help and advice - KiwiGeoff:D
 

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Hey Geoff, my S3 had a 42 on the rear and i found would need changing down from 6th to 5th sometimes to get a move on when 2 up. I've gone to a 45 rear now and it's better. Still not quite the hoodlum machine I want, but it's getting there.
 

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Discussion Starter #9
Speed triple gearing

Thanks Tripletom.

I've only got the 5 speed box so I'm hoping the result will be similar to the 6th gear on the highway. Time will tell.

Cheers Kiwigeoff:D
 

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please do tell us where to get the tach fixed if in fact its reading does get re-fixed and becomes accurate. Cost?

Thanks!

:D
 

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Let's see your teeth

On my Daytona 955 '06 I went from 18t-43t to a 45t rear. the 43t gave great fuel consumption, but most of my riding on this bike is solo weekend short blasts.

Basically, the 45t is the way to go. On the TBS I went to a 44t (couldn't find a 45t) and it's a good happy medium. I would've thought that the 43t would've been fine. I'll be getting a 5-gear SP3 T309 soon hopefully, so I should be able to appreciate what you're saying then.

Finally, a single tooth down at the front is worth two at the back.


So, you could go 17t - 43 for lower ratio or 19t for the higher one. Jack Lilley does a 19t in its product list for carb model Triumphs.
 

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Discussion Starter #12
Show us your teeth

Hey Senyorsimon I'm going for less teeth on the rear. I can appreciate that some of you want to gear down for more thrills but I'm looking to moderate engine speed at our legal limit (only 100 kmh here in NZ) as I spend most of my time on the highway - hence reducing teeth on the rear. Standard gearing on the 5 speed t3 is already 17/43 by the way and even with standard gearing I seem to get 55-57 mpg - I guess I'm quite sedate.

Appreciate your comments - KiwiGeoff:D
 
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