Bigger Front Sprocket

[PhantomII]

Has anyone installed a bigger front sprocket something like a 18t on their Street Twin? I would like to lower the RPM's when I'm running at 70 mph and it seems that the motor has plenty of low end grunt that it won't affect it's low end.

 

[shanered6]

sorry can't help with the street twin ! but i just installed a 19T front sprocket on a 2003 tiger 955i which for some reason was on a 17T front ?

 

[Baldeagle]

Thinking about the same thing with my new to me America,still looking for that sixth gear or a little lower revs in fifth,let's see what the experts come up with!.

 

[PhantomII]

I talked to my mechanic about the bigger front sprocket and he said we can't do it because it messes with the speed sensor for the ECU and if I change it the motorcycle won't run right because it will try adjusting the fuel delivery trying to get the speed sensor synced up. He also said it will void my warranty.

 

[Rocky]

I talked to my mechanic about the bigger front sprocket and he said we can't do it because it messes with the speed sensor for the ECU and if I change it the motorcycle won't run right because it will try adjusting the fuel delivery trying to get the speed sensor synced up. He also said it will void my warranty.

Interesting information.

 

[Baldeagle]

Well I bit the bullet and now have a 19 tooth front on my 2007 injected America.
Doesn't seem to have made any difference at all to the starting or running BUT boy is it a better ride,hang on to the lower gears a bit longer,cruising speed about 2-300 revs less at 110 kph,for me a much more refined ride.
Not checked the speedo against GPS yet but will do when I get back to France.
It only cost around €25 non Triumph but can't see how it would avoid warranty,you could always swop back if needed too when going to the workshop not a big job.

 

[shanered6]

Well I bit the bullet and now have a 19 tooth front on my 2007 injected America.
Doesn't seem to have made any difference at all to the starting or running BUT boy is it a better ride,hang on to the lower gears a bit longer,cruising speed about 2-300 revs less at 110 kph,for me a much more refined ride.
Not checked the speedo against GPS yet but will do when I get back to France.
It only cost around €25 non Triumph but can't see how it would avoid warranty,you could always swop back if needed too when going to the workshop not a big job.

ye its made a massive difference to my tiger it now runs much smoother and yes ! 70mph is now at 4000rpm instead of 5200rpm and what a differance to fuel usage im using far less than before .

i can't see how it would mess with your running as the speed sensor is just a pick up type sensor and the only affect it has on the running of the bike is in conjunction with the rev limiter , also if that was the case then your bike would not run very well when stood still ?

 

[PhantomII]

Ended up going with one tooth less on the back installed a new RK chain and a new front sprocket took it on the interstate and gained an additional 10 mph on the top end, I always knew they had these things under geared.

 

[SarahP]

Newbie question here -- although my 2017 ST is a joy to ride, I find myself hitting the shifter at the upper end, too, looking for 6th gear. Why wouldn't the smart bubbas at Triumph (guess I should say lads, not bubbas!) do this from the start?

 

[Baldeagle]

Maybe because they think most riders prefer acceleration and don't worry about the fuel consumption and take a middle ground approach.
Do we notice if we are a little slower to 60?
I certainly don't and enjoy the less frantic ride,but then I am an old git and guess us old gits keep our bikes longer,just a thought.

 

[shanered6]

I was doing the same thing on my tiger allways looking for that extra gear so i went one tooth bigger on the front at first i loved it !.......but then i noticed i was constantly on the clutch lever in town and and on twisty roads was always ether in to high a gear or two low a gear ! so ive gone back to the original gearing and find it far better know .
Ive even tried a tooth down on the front which was brilliant fun but i could not keep the front wheel down with the wife on the back which become a real hand full in the town , so in conclusion the factory gearing is about the best compramise of power and safety .

 

[PhantomII]

I haven't lost any acceleration and I haven't had any issues riding in town, I don't know if you guys have even ridden a Street Twin but I'm hear to tell you it has more than enough torque to pull a rear sprocket with one less tooth, my only complaint about this bike was when you are riding at 85 to 90 mph which is how fast they drive on the interstates where I live the motor seemed to be straining until I made the change to a smaller sprocket.

 

[DaveM]

I would have not thought that at that speed it would feel like that.

 

[shanered6]

I haven't lost any acceleration and I haven't had any issues riding in town, I don't know if you guys have even ridden a Street Twin but I'm hear to tell you it has more than enough torque to pull a rear sprocket with one less tooth, my only complaint about this bike was when you are riding at 85 to 90 mph which is how fast they drive on the interstates where I live the motor seemed to be straining until I made the change to a smaller sprocket.

Sorry bud i was talking about the front sprocket which one tooth is the equivalent to 4 on the rear thats why the differance is so much .