185s gear ratio

[zackdauzat]

Im needing to replace both sprockets on my 1983 185s. I see there is multiple options. I found a 10,11,and 12 tooth on the engine drive sprocket and i found a 40, 41, & 43tooth rear sprocket. What way should i go to get a little more low end grunt from it?

[ATC King]

You've got to keep up with chain length too.

There's only so much adjustment available and some sprocket combinations will leave you with a chain that's either too short or too long. I'm not just talking about the stock length chain, it's any possible length chain that doesn't include a half link.

Half links are a bandage, not a solution. It's like using two master links, just adding another weak link to the chain. Avoid them whenever possible.

If you do end up with a situation that has your new setup already through half of the available adjustment, running the highest quality chain available will make that work out for much longer.

[zackdauzat]

Just bought a new 520-82L o-ring chain. I have no problem getting a longer chain and shortening it to proper lenght. Was wondering if anyone used any of the above combos with success other than the stock 11-40 tooth.

[zackdauzat]

Just found this chart if it will help anyone else out.

264243

[Blmpkn]

If you want more low end your going to want to go to a smaller front sprocket or a larger rear sprocket.

*I see now that thats what the chart you posted explains lol.

[ps2fixer]

What are your goals with your machine? If you want a faster road bike, go higher geared and/or larger tires, if you want more grunt for hills, mud, off roading, wheelies, etc, go lower gear, or assume Honda has a good sweet spot and stick with the stock ratio.

You can calc it as rear sprocket/front sprocket to give the gear ratio for number of turns the engine output shaft turns per turn of the rear axle. So a 40/10 combo is 4.0 gear ratio. If you want about 10% faster speed, then times the number by 0.9 (90% of current number) which would give 3.6. With that target, here would be your options:

36/10
40/11
43/12

I got those numbers by front sprocket times gear ratio, aka 10 * 3.6 = 36. Math, yay fun stuff lol.

If you have different numbers in mind, post them and I can run through the math real quick. Same goes for the tire size, you calc how far the tire travels per turn (circumference of the tire) and you can compare different gear ratios with different tire sizes. If you make your tires 10% bigger, but make the gear ratio 10% lower, then your overall performance should be very similar to before, just more spinning mass/weight so slightly slower take off.

Here's a page with the stock gear ratio and more. The sprocket gear ratio is called the final reduction.

https://atvmanual.com/honda/atc185s/1983-specs

The service manual doesn't seem to say what the stock sprockets are, but if the front sprocket is 11 tooth, the math comes out as the rear should be 41 tooth.

FYI, you can have custom sprockets made, my dad had a crazy idea of putting 28in mud tires on a yamaha warrior long ago, he got a 52 tooth rear sprocket custom made (stock was 40) and it was still too high geared with a 11 tooth front (stock 13). It was a blast in the snow though.

[zackdauzat]

Thanks... No everything is stock size on it.. was just looking for a tad more low end grunt. I haul a yard trailer full of crap all the time or with kids in it. Almost done restoring this thing. Will do a build up thread soon.... from parts bike to 1983 new bike...