Bonneville America Forums Forums Technical Forums Performance Mods 17t vs 18t Sprockets-A Comparison

For all of you who are considering the switch from 16 or 17t stock sprockets to an 18t, here are the speeds vs RPM vs Gear comparison for both. There is a GearCalculation program at www.ironjungle.com where you can play with all your ratios/tire sizes, etc... to see where you are with different setups. This is a stock America rear tire size of 170/85-15, and is in my photo gallery for downloading if you want or I can e-mail it...

http://www.bonnevilleamerica.com/photopo...t=1&cat=500

I tried to post an image of this, but all it keeps doing is putting the link between the image brackets, so...

That's good info Gregster, thanks.
The other day a couple of us were riding between beer stops and calculating speed/rpm in reference to a 18 toother and the belt drive. My belt gives me almost identical, if not slightly higher speeds, as the 18 in your chart. This is by indicated mph on the speedo, which we all know to accurate to 1/100000th of a mph eeh?
And is was also identical (close enough) to mike on his BA with the 18t.

Thanks Pat, now, as soon as I get one of those "equally as accurate to the 0.000001RPM Triumph Tachos", I'll be able to know eactly how fast my engine is turning and by how far I'm exceeding the speed limit at every second...

Hey Pat,

Did you check out the BeerCalc program they have on that site?

It looks like it calculates the inverse proportion of alcohol consumption and your maturity level. Figure for you it would be about 17.547 ounces of beer to get you back to kindergarten, eh?

Sorry Phil, I can't run those cheesy old 16 bit programs.

Stayin dry are ya? Looks like you're all about to get washed right out to sea along with the Cubans.

Staying dry is definitely an issue right now!

Did manage to get 100 miles on her yesterday but today and all the rest of the week looks like a washout...

Oh well, the tale is that when we get rainy weather in May and June, the hurricanes stay away. I say, let it friggin rain!!!!

All I know is that my bike is more relaxed at highway speeds with the 18t and that's all I cared about. As far as the low end I didn't really notice any change because I really don't push the bike hard at all.

Bayern,

I have just received my 18t sprocket and will be installing tomorrow. Looked at your gallery. That is one good looking BA! What kind of pipes do you have on your bike? They look great!

Thanks jmf!! Bub Slashcuts, 130 Mains, TBS Needles (no shims), 3.25 turns out on the Pilot screws. Runs like a champ...