sprocket change results

On a 1980 Puch Maxi 1.5 hp. Changed the front sprocket from 14 to 18 teeth. Changed the rear sprocket from 45 to 40 teeth. Actual speed increase was from 26.7 to 31. 8 mph. (I have a digital speedo.) Some loss in acceleration. Theoretical (no load) speed increase based on ratio of sprocket change is for a top speed of 38.5 mph. Need more power!!

Change one back

Either one of those changes individually is pretty big.

Changing both that much seems TOO big.

If you try changing one of them back to the original size... you will likely get both more acceleration AND more top speed.

Re: Change one back

I'm with Fred on that! WOW,that's a lot to expect from 1.5 hp! I'd go back to the 45 T on the rear .

Re: Big Money

Some company paid an engineer big money to figure out an appropriate ratio for the given horsepower, weight, speed and RPM range.


Re: Big Money

Mopeds (1.5 hp type especially) were designed to not exceed a certain speed. This was by law. Everything possible was designed into the moped to achieve this limitation and make it extremely difficult to alter. If it was easy to change the speed and power of a moped, we probably would not have this website. Therefore, it is our mission to make every attempt to make these things go faster and share constructive information with other interested mopeders. And, I must add, at the least possible cost!

Re: Big Money

So are you going to change one of those sprockets back or not ?

Re: Who got sprockets

I had only borrowed the sprockets from a friend. The Puch Newport II comes with the 14 front and 40 rear sprockets. It has a reduced gear box compared to the Maxi. I am now back to my original sprockets, but if I had the 14 front and 40 rear I would use them. I live in an area with no hills and do not worry about acceleration. But, I do not wanrt to pay fifty bucks for a set of replacement sprockets unless I can add more power. So, I will work on power increase before I permenantly change sprockets.

Re: correction

Meant to say, "If I had 18 (not 14) front and 40 rear I would use them"

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