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best choice for 5 speed gear ratio change

thanks dolt. i'm actually talkin about changin the tranny pulley from a 32 tooth stock to a 34 tooth, not a 30 tooth. i've also heard from goin from 32 to a 30 on a soft tail means a belt change. i haven't heard anything from anybody whose done the 32 to 34 tooth on a roadking, whether that requires a change in belt length. from what i hear, that change can be made without a change in belt length (i think that was on a soft tail but not sure).
i think it was dennis kirk that told me that the change i'm talkin about (tranny pulley from 32 to 34 tooth) lowers the rpms about 240 at 60 mph.
 
I understand the change you are contemplating but was using the 30/32 as an illustration that a two tooth change, either way, 32T to 30T or 34T will have the same result. The belt will be too short or long to allow adjustment for proper tension. Of course there are exceptions to every rule but the general rule is one tooth, up or down, and the OEM belt works but two teeth up or down requires a belt change. As you know, changing a belt on your bike is quite a job; not one most would want to repeat, so I understand your endeavor to be sure before you dive in. Personally, I just don't see the cost benefit but that's JMHO.:D

There a gearing calculators on the BigBoyz and Baker websites that you can use to calculate the rpm drop resulting from a pulley change. My gearing calculator says that two more teeth on the trans pulley will drop rpms about 150 at 60 mph.:hii

Ultima offers a six speed for about $500 and a gear set for less. Mixed reviews, some love the unit and some have had problems. Rivera also offers a six speed gear set for about $900 but don't know much about it. If I was going to run the Ultima unit I would get the whole transmission so if it went down, I could replace it with the stock unit.:s
 
The belt is 14mm pitch so one tooth = 14mm split top and bottom of the belt run = the axle moves forward or back 7mm to a first approximation. (a bit more than a quarter of an inch). For two teeth your axle needs to move 14mm forward or back (a bit less than 9 sixteenths of an inch) again to a first approximation, as in it might need to go a bit further, or not, to get the tension right.

So, you can check the axle position with the OEM belt properly adjusted and see how much room you have in front of the axle for forward movement. If you have about 16mm, the OEM belt with a 32T trans pulley might work but I doubt that there is that much space for movement in either direction.:hii
 
The previous post addresses axle movement correspondent with a belt change but does not address axle movement correspondent with changing tooth count on the trans pulley. I thought I had that information in my notes somewhere but cannot find it. Of course, it is a function of the increase in diameter of the trans pulley to accommodate the additional teeth and that is the formula I have been looking for but can't find.:(
 
dolt, I enjoyed reading your comments! I learned something. Thanks for that! :bigsmiley12:

oldscoolz, I am sure you could do anything to make your bike works. it could be either lower or higher $$$ Depending on yours. I would just get new 6 speed tranny but it is your bike so that will be your call. Thanks for starting this and make it more interesting! Looking forward to your decision and results! :bigsmiley12:
 
thanks to all for the comments. special thanks to dolt. u've given me some things to think about and hit most of my concerns right on the head. now if u'll just deliver me that dopeslap, i'll be fine.

i was originally thinkin, i'm gonna be changin my belt soon, so why not make this tranny gear change at the same time? i'll let u know what i decide and how it goes once the weather goes down and i start wrenchin.
 
A parting thought for now.

Aside from the belt issue, the major downside to replacing the 32T pulley with the 34T pulley is that the lower four gears are affected as well. Not such a big deal with a motor that is making 120TQ/110HP but, IMHO, will make a stock bike feel like it's dragging an anchor.

If you overcome the belt issue, here's another option for your consideration. Johnson Engineering offers a "kit" call the Twist Gear. The kit includes a new countershaft and installed with stock primary and secondary gearing, the Twist Gear will convert the OEM five speed tranny into a close ratio four speed with 10% more torque multiplication in the lower four gears but retain the 1:1 ratio in 5th. Now, install the Twist Gear with a 34T trans pulley and the lower four remain close ratio but the same torque multiplication as OEM but 5th gear cruise rpms drop. I run the Twist Gear in my 107" '02 FLHT but for the lower ratio in the first four but final drive is still 3.15; I love the setup. The kit runs about $500 and not difficult to install. Not saying it is for you but wanted to make you aware of the potential. You can check the link and details; lots of information including charts for working out final drive ratios with different pulley combinations, etc.

Harley davidson parts, gear ratio, motorcycle performance parts, overdrive transmission

Let us know what you decide to do and how it goes. Good luck with the project.:hii
 
Oldscoolz,
Stock belt and 31T pulley for sale on HTT for $280 shipped to lower 48; may not be of interest but thought I would let you know.:s

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Oldschoolz,
Thought you might find this interesting and of some assistance.

Calculating Belt Length - Wisc-Online OER

Use the above method to find the total length of belt. I think a Harley drive belt is 14mm from tooth to tooth. Convert 14mm to inches and divide that into the length of the belt for the number of teeth. .03937*14mm=.551. Some rounding should be applied and I would likely round up rather than down.:hii
 
some interesting info there :) ive been having the same thoughts about mine i also would like to drop the revs a bit mind you im still very new to Harley and i could be applying to much mechanical sympathy to my old girl.

a 6 speed gearbox has crossed my mind but sheesh it would cost a bomb to get one over here :shock
 
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