Polini puch gearing question

I have a polini puch e50 with a proma circuit pipe. I way 235, and the bike is for daily commuting in New York (so, I want a stop-and-go bike that will cruise all day at 35 and hit low 40's when I need it to). What kind of gearing should I be running? Ideally, I would like to calculate it in terms of rpm, but I'm not sure what the ratio of the crank shaft to the primary gear is, and I'm not sure what rpms the proma hits at. Does anyone know what that ratio/those rpms are?

Thanks a lot - I couldn't possibly do any of this stuff without this site!

Re: Polini puch gearing question

*weigh

Re: Polini puch gearing question

check out this attachment /\

I dont know what kind of carb you're running, but it's safe to say that you should be able to hit 9000 RPM with your set up.

Re: Polini puch gearing question

Wow that's AWESOME, thank you. I'm running a 15 bing carb for break in, btw, and then I'll put my 19phbg on it when it's broken in (and, hopefully, when the malossi reed block's available again).

Re: Polini puch gearing question

no problem. with some decent tuning you should be able to hit 10000+ RPM.

Re: Polini puch gearing question

Calculating from experience 14 X 45 would do it real good but I would choose 15 X 45 sprockets

Re: Polini puch gearing question

i've built over a dozen polini's for friends and myself, 16/45 is the best set up for city light to light performance... i usually do 16/45 if i'm running a techno boss or a homeot 4p, and 17/45 on estorils cause the estoril gives great off the line response and the extra tooth helps on top end... if you wanna lower your rpms at higher speeds, the drop you rear gear to a 40 tooth and run 16/40...

Re: Polini puch gearing question

I weigh 215. stock gearing 16/45 does what you're asking easily with the Polini for me. (those little skinny guys don't fully understand the difference another hundred pounds makes.) in fact, you've described pretty much how I always ride my Polini, but up to this point I was only using a 14mm carb. Just upgraded to a 15mm! and my Leovinci pipe has a mid range band(kicks in at 18mph) but no low or top end. don't know where your Proma's gonna hit.

Re: Polini puch gearing question

Ok great it sounds like 16/45 is about where I want to be. That's about a 0.36 gear ratio. The rear sprocket I've already got is a 40 tooth, so I'm thinking a 14 front sprocket will get me to a 0.35 ratio, which should be just about right - correct me if I'm off base . . . the only thing that matters is the ratio, right? Thanks again for your help.

Re: Polini puch gearing question

14/40 is a little slower. that's what I went to when I put snowflakes on, since I don't know where to get Grimeca sprockets. it seems to react similarly, just a couple mph slower all around.

Re: Polini puch gearing question

Yeah that's the thing I've got snowflakes. Should I go to 15 teeth (0.375 ratio)?

Re: Polini puch gearing question

I run a 15/45 on my athena kitted maxi. I live in the mountains west of Denver and I need some hill torque. You loose top speed, but off the line or pulling hard up a steep hill that ratio rocks it. The stock 16/45 would bog on me at starts and climbs. The 15/45 was just enough to not have to pedal at all without too much sacrifice in the speed department. For light to light on the flats it should be what your after- strong start torque and good solid low to mid power. I don't think you'll miss the 45-50 mph range doing light to light traffic riding. It's a strong 0-40 mph range. I hope this helps.

Re: Polini puch gearing question

The air is much thinner around Denver

Re: Polini puch gearing question

why would that effect gearing?

Re: Polini puch gearing question

gearing no, but engine performance really suffers. Thinner air = less oxygen = less gas in mix to maintain proper fuel/air ratio = lower performance all the way around.

Denver is at 5,280 ft. (on the steps of the Capitol Building).

I live at 8,700 ft. in the mountains to the west and I have to run a 45 jet (stock is 65) in my 17mm. Amal and it's a little on the rich side.

James, if you live down around sea level then you should have more power than I do. I'd recommend a 15/45. Just drop a 15 front sprocket via circlip to change, and back out your tire to eat up the chain slack.

It's only a one tooth jump on the cheaper of the two sprockets to replace. The effect will be noticeable but not drastic, then you will have a better feel for what you want to do, if any at that point.

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