Gearing Question

[ZacH_GrifF]

I’m in the middle of getting my fully suspended 185s build back rolling again. Pretty much nothing is stock now so I thought I’d throw some back story in and see what y’all might recommend.

It’s got a 83-84 250r front end, a warrior 350 swingarm on the rear, the engine is now a 200cc with a 10.25:1 piston and a xr200 cam, and 200x dg exhaust. I have opted to run a 1.25” go kart axle due to chain alignment issues with my original setup trying to run the stock 185s axle.

I’m going to run 20” tires in the rear and trying to figure out what gear ratio to run. Since I’m running the go kart axle now the rear sprocket sizes are pretty much limitless. I’ve seen it recommended to run 13/37 for a 200x with 20s. But I’d like to keep my rear sprocket as small as practical. So would 11/34 or even 12/35 be a decent go at it?

I’ll be mainly riding trails with this bike. Don’t plan on doing any track riding or Mx stuff. Just putting around and maybe the occasional trip to a dune/sand pit.

Any suggestions appreciated

[MrConcdid]

That's cool.
That swing-arm looks like it was made to fit your bike.
Just a suggestion a piece of tube and a long bolt through the farthest back hole of the pillow block bearing may help keep them square and add more
strength to the two ears on the swing-arm.

I think you have chosen wisely you have limitless placement and parts (sprocket, hubs, disc brake) options.
When you get it finished, post part numbers and suppliers, I would love to copy this design.

thanks for posting
MrC.

[ZacH_GrifF]

Thanks. I just might add one or two of those tubes. And I kinda have a build thread I started a while back. I’ll be sure continue adding more to that post

[Dirtcrasher]

Those flange mount self aligning bearings usually have cast iron housings, I'm not sure if that's a good choice for a rear axle on a trike...

[ZacH_GrifF]

Those flange mount self aligning bearings usually have cast iron housings, I'm not sure if that's a good choice for a rear axle on a trike...

I appreciate the concern but I’m gonna run this route till I hit issues. I will more than likely eventually make my own bearing hub on a lathe to fit the standard bearings this axle takes. In the mean time I can get everything else going such as breaks, chain alignment, and gearing.

Anybody have any input pertaining to the gearing question?

[350for350]

Since you're wanting to keep the rear sprocket as small as possible, I'd say to try out the 11/34 gearing first. That way, you can try that out and if you want higher gearing, you can go to the 12 tooth front sprocket. I wouldn't bother trying to change out the rear sprocket for one tooth. The closest thing that I have to compare to your trike is my AutoX. It has the 11 tooth front sprocket and whatever rear sprocket was on the 200X. I don't think that I've ever bothered to count the teeth on it. I was thinking about using a 12 tooth front sprocket, but I and a couple of trike friends think that it's great just the way that it is now.

[El Camexican]

A little searching on the Internet will find you some motorcycle friendly sites that have calculation boxes you fill in with tire circumference, chain size and gear teeth to get speeds and ratios. If you don’t know the final drive ratio of your transmission you can just invent one and stick with it for all the scenarios you plumb in. It skews the speed data, but if all you’re trying to do is get back to stock ratios it will be fine.

Start with your known factory specs to conclude your original ratios and then play with your variables to determine what gears will work with your aftermarket parts.

You don’t want to go up or down more than 1 tooth on the front sprocket on any machine as it usually means your going to rub a case, or tear up the swing-arm protector. Best to adjust at the rear if possible.

[ZacH_GrifF]

Since you're wanting to keep the rear sprocket as small as possible, I'd say to try out the 11/34 gearing first. That way, you can try that out and if you want higher gearing, you can go to the 12 tooth front sprocket. I wouldn't bother trying to change out the rear sprocket for one tooth. The closest thing that I have to compare to your trike is my AutoX. It has the 11 tooth front sprocket and whatever rear sprocket was on the 200X. I don't think that I've ever bothered to count the teeth on it. I was thinking about using a 12 tooth front sprocket, but I and a couple of trike friends think that it's great just the way that it is now.

Thanks 350.

[ZacH_GrifF]

A little searching on the Internet will find you some motorcycle friendly sites that have calculation boxes you fill in with tire circumference, chain size and gear teeth to get speeds and ratios. If you don’t know the final drive ratio of your transmission you can just invent one and stick with it for all the scenarios you plumb in. It skews the speed data, but if all you’re trying to do is get back to stock ratios it will be fine.

Start with your known factory specs to conclude your original ratios and then play with your variables to determine what gears will work with your aftermarket parts.

You don’t want to go up or down more than 1 tooth on the front sprocket on any machine as it usually means your going to rub a case, or tear up the swing-arm protector. Best to adjust at the rear if possible.

Thanks man. I have been playing around with gear calculators I was just kinda wanting some input from guys who might have a similar setup. Ideally I’m thinking my best route would be to kinda copy the final ratio a 200x has and adjust for the 20s instead of 22s.

[El Camexican]

Thanks man. I have been playing around with gear calculators I was just kinda wanting some input from guys who might have a similar setup. Ideally I’m thinking my best route would be to kinda copy the final ratio a 200x has and adjust for the 20s instead of 22s.

Cool, I figured you had too many variables in your setup to get a simple answer. I learned the hard way when I spent over $80 on a custom offset front sprocket that was wrong because I was to stupid to realize that when I was converting from a 630 to a 530 chain the sprocket diameters totally change, i.e. a 530 18T is about the same diameter as a 15T 630.

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