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skoto1 05-13-2009 10:25 PM

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triking my goldwing 1200 i have a gearing question i am going to be running a 4:25 rear gear at the rearend. tires are 6.5 ft around on 17" wheels. my question is will i be able to take off with the trans gears i currently have 1st is 2.643 any help? i figured at 1000 rpms in 5th i'd be doing around 57mph.

k1w1t1m 05-14-2009 08:22 AM

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I don't know what the final drive ratio is for a 1200 but an 1100 is 3.10. If the trike tires are close to the same diameter as the bike tires then the gearing will be off quite a bit. A search around some four wheel drive sites might reveal a calculator. I think the formula will look something like this:

old tire diameter/old final drive ratio = new tire diameter/new final drive ratio

skoto1 05-14-2009 09:32 AM

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final on the 84 1200 was 2:88 my tires are 17" but are about the same size in dia. thanks i'll look around.

sandiegobrass 05-14-2009 01:22 PM

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Rear end ratio of 4.25 sounds much too high ... The stock GL1200 rearend is 2.83.. Your engine rpms would be much higher.. Here are my results (Actual Spreadsheet here to play with)

[Also, if you want to unlock the whole sheet so that you can change more than just the red and green cells, the password is GL1200 and that is upper case GL]

skoto1 05-14-2009 01:57 PM

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yea i know i found a calculator last night and i'm screwed if i can't find some way to bring the rear gear closer to the 2.833. tires would have to be too tall i was thinking of some type of gear drive to go between the trans and rear end cause i can't find a ring gear and pinion for the rear end i'm using. may just have to cut it out and start over with a different rear end that i can get a matching gear set for. hate to but don't have much chose unless i can find a gear box that will work for me. nothing ventured nothing gained.:stumped:

sandiegobrass 05-14-2009 02:04 PM

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I don't know what you are using, but buying a whole rear-end from a junk yard is proably cheaper than a ring and pinion..a cut downChevy S10 comes to mind..

except now that you have posted the pic, I can see you are farther than that..

skoto1 05-14-2009 02:05 PM

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looks good but it want go fast i'll have to change it.

skoto1 05-14-2009 02:10 PM

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no don't mind the redo i was just trying not to have to get the axles resplined as that can cost more than the rear end several time over as it stands i only have a few hundred in the whole conversion so still working on it. i would buy a ring gear but i can't find one very rare rear end to start with 1958 alfa romeo.:baffled:

Bagmaster 05-14-2009 02:22 PM

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Correct me if I'm wrong but with a ratio of 4.25 wouldn't you want to use smaller, shorter tires and rims than tall ones to get it to work?

k1w1t1m 05-14-2009 02:31 PM

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Another gearbox will increase the inefficiencies. Many of the common Chevies and Fords have a 3.08 (or close) ratio that should work quite well and are probably pretty cheap and certainly easier to get parts for should you need them.

The trike looks good. Keep the pics coming.

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