changing final gearing on a Commander

[andygbsmith]

I want to change the gearing on my Commander. 1 tooth moore on the front sprocket would do it but is there enough room inside the chain cover and are there sprockets available? I assume the output shaft is the same as Tridents.ANY thoughts welcome.Andy

[Richard Negus]

Andy, The biggest front sprocket to go in is 18T, standard for a Commander is 17 and 43 rear. You can go down to 42 or perhaps 41 at the rear before the chain comes close to the neck of the rear sprocket cover.Front sprockets are the same as old Triumph; 18T is part no. 57-4784.

[andygbsmith]

Thanks for the info Richard I am looking to drop the gearing back to near normal 4000rpm = 70mphI find the fuel consumption suffers with the supreme Commander gearing. Did you ever alter yours?Andy

[Richard Negus]

Andy,Standard 17/43 will give you better acceleration.Mine is 18/42 and on the last Scotland trip, I averaged 47.7 mpg of varied running over 1600 miles. Tony, with me most of the way on a standard Commander, was doing about the same I think.With a 110/90 or 120/80, standard gearing gives a true 15.6 mph per 1000 rpm, so 4000 is an actual 62mph. Speedometers, by law, must read fast and are allowed to indicate up to 10% higher than the true speed.

[johnbirchjar]

I fitted an 18 tooth sprocket to the g/box on the Classic some years back,hoping to improve fuel consumption,made little or no improvement,just reduced engine revs by about 500.not realy worth the bother.ride safe,J.B.

[Dell Boy]

My red commander has 18 tooth fitted & grey one 17 tooth. As J.B. says the effort involved doesn`t really pay back in overall improvement & you do lose some low down acceleration.Derek.

[andygbsmith]

OK thanks for the info. I average about 45MPG on a run with the supreme Commander but averaged 50mpg on my old bike so assumed the lower gearing was the issue.I probably wont bother as it sounds like agro to do.Andy

[Richard Negus]

It's worth weakening the mixture 1/4 turn (that's the screw with two slots at right angles down a hole on each carb). Unscrewing makes it weaker.The mixture is affected throughout the range so you may find some roughness at low throttle when warming up.Make a note of the screw positions so you can return to the original settings!