Bonneville America Forums Forums Technical Forums Performance Mods sprocket ratios

i'm changing my chain and sprockets and was looking for some info on gearing ratios. the stock ratio is 42/17 on my 02. the last person who installed my chain sprocket (before i was doing things myself) installed a 46/17 setup. i recently put an 18 on the front because i wanted a better cruising gear. i just came across this article and thought i should share. i may just go back to the stock 42/17...

That now has me thinking. I was told going up one tooth infront was equal to going up 3 in the rear. I always wondered if that was true.
Anywho im running 18/42 and i think its still a little high at 65-75.
Sorry this is more thking out loud than any help in the matter.

do you mean maybe 3 up in the rear is equal to 1 down in the front? that would make sense to me but maybe i'm way off.

this may be helpful... http://www.gearingcommander.com

Personally I run a 42/19 and I cruise on the highway at 70+ with no issues.

Hahaha i donno. This stuff confuses me.

i was just looking at that gearing commander site. pretty cool. i also have a larger rear wheel so that adds to top speed. i don't know the primary gearing so i can't use the gc calculator but going off the ratio chart in the tech vault, my current 46/18 setup is 2.56 and the stock 42/17 is 2.47. so i'm getting slightly more bottom end than stock. factoring in the bigger wheel it might all balance out. idk. i can't imagine there's too noticeable a difference. i did read somewhere that bigger sprockets wear down slower but i also read something about a larger sprocket being harder on the primary drive. can anyone clarify this?

fellas i'm having a hell of a time finding anyone who carries our REAR sprocket in stock. does anyone know if the america/sm uses the same sprocket as the standard bonnies? i'm talking about the diameter from bolt to bolt. i one site i see the ba's as 110 and standard bonnie as 140. but then i'm seeing on some that they all the bonnie models including our ba's take the same rear sprocket.

There are a bunch of sellers on EBay who push the envelope of different model fitment. As an example, Bonneville seats that are advertised to fit Spdy s/America s, rear tires in sizes that cross straight over (uh no), and many sprockets that absolutely do not fit both models. All they care about is that their items get listed as many times as possible. So Caveat Emptor, just because they say it will fit, doesn't make it so.

Fasteddy sells the OEM 42 tooth here: Sunstar Steel Rear Sprocket

the standard Bonnie's and ba/sm have different hubs and definitely use different size rear sprockets. our bikes have a smaller inner diameter. I just noticed a honda parts cross reference in the vault for 530 chains. does anyone know if those honda bikes listed are for rear or front sprockets or both? also does anyone know if t birds use the same sprockets as us but 530?

I also run a 19t with the 42t on 08 865 BA and works really well!!!!!!

i run 18/44 on the tiger

my plan is to run 18/45 with a 530 chain sprocket. just trying to find parts. does anyone know about the t-bird question i asked above?

the thunderbird uses the same sprockets as us but in 530.

I thought stock was 17/42 for the 790cc motor and 18/42 for the 865cc?

IIRC, the 790 Speedmaster came with a 16 and the 790 America was set up with a 17.

Yes Sorry,I was referring to the America.
I have the 18/42t on my 2007 America.I keep thinking to try the 17t front but I do mostly highway riding so .....

I roll with an 18 tooth sprocket up from also. Once you get up over 70rwhp you don't notice any lack of acceleration