Reducing transmission pulley tooth count

[joker9r]

I'm looking for any feedback from folks that have reduced there transmission pulley to a lower tooth count. What tooth count did you go with and what Negative or positive results did you get. I'm looking at reducing to a 31 tooth but I don't want to loose too much top end so I may just do 32. Here are the numbers from Baker...

Pulley Tooth Count>>>>> 29______30_______31______32______33______34
Wheel Torque Incr>>>>> +10%____+7%____+3%______0______-3%____-6%
Cruising RPM in 6th>>>> 3017_____2916____2822____2734____2648____2573

 

[Five Five]

Interesting post....I too want to change mine out...I want to lower RPM's when in 6th gear... looking for an engine sprocket tranny pulley combo

 

[armad]

I'm looking for any feedback from folks that have reduced there transmission pulley to a lower tooth count. What tooth count did you go with and what Negative or positive results did you get. I'm looking at reducing to a 31 tooth but I don't want to loose too much top end so I may just do 32. Here are the numbers from Baker...

Pulley Tooth Count>>>>> 29______30_______31______32______33______34
Wheel Torque Incr>>>>> +10%____+7%____+3%______0______-3%____-6%
Cruising RPM in 6th>>>> 3017_____2916____2822____2734____2648____2573

I asked a similar question quite a while ago. It seems no one has done this yet. I have an 08 Mutt also, and I was looking at a 32. I have it but haven't installed it yet. I am not sure, but there may be some belt length issues. If a shorter belt may be needed that would add to the costs. The pulley I have is steel and is quite heavy. You might want to look for a lighter pulley. Aluminum wears quicker, unless you can find one that is hardened or treated in some way to reduce wear. I don't know what they call cruising speed in the chart, but for me in 6th gear at around 65-70 mph the motor seems to be lugging some. That is why I wanted a lower tooth count pulley. I am thinking maybe a 31 might be a better choice. For me I am not interested in top speed, just down low acceleration and cruising around 65 mph in 6th. Let me know what or if you ndo it and how it works out.

 

[BigDogBro1]

Upshift to 5th and run the RPM's where the engine won't lug..2500 -3000 RPM's is where you should be.

S&S says these engines are not for luggers and will run better and last longer at the higher running RPM side.

Bakers 6th gear is a gear ratio of 1:1.

A larger front trans pulley will lower the engine RPMs.

 

[joker9r]

Yup... smaller front pulley will yield higher RPM and better low end performance. it appears that going smaller than a 31 tooth would require a belt change. I asked Baker why Big Dog went with the larger 34 tooth sprocket and am waiting for a response. Will let ya know what I find out.

 

[Th3InfamousI]

How is Baker calculating that cruising RPM in 6th? What speed? And does it hold true for the overdrive?

According to the manual you shouldn't even get into 6th gear until 80 mph or you run the chance of lugging the motor. If you go with a smaller pulley and 30 or 31 you might be able to use 6th around 70'ish.

 

[armad]

Upshift to 5th and run the RPM's where the engine won't lug..2500 -3000 RPM's is where you should be.

S&S says these engines are not for luggers and will run better and last longer at the higher running RPM side.

Bakers 6th gear is an overdriven gear ratio 1:1.25 or something like that.

A larger front trans pulley will lower the engine RPMs.

That's what I do with mine, run in 5th. Hardly ever use 6th unless I am on the freeway at 80 or above, which I never go above 80. It would be nice tto be able to use 6th gear though. That's why a smaller trans pulley would get the rpm's into the range so you are not lugging the motor any. Around 2850 would be about perfect.

 

[armad]

Yup... smaller front pulley will yield higher RPM and better low end performance. it appears that going smaller than a 31 tooth would require a belt change. I asked Baker why Big Dog went with the larger 34 tooth sprocket and am waiting for a response. Will let ya know what I find out.

That's what I want. Was it baker that told you running smaller than 31 tooth would require a belt change? I did this on another bike I have and didn't have to change the belt, but now don't have a lot of adjustment room left. And if you look real close you can tell a little bit that the rear wheel isn't perfectly centered in the fender (front to back) when looking at it from the side. Not a real big deal, but I am picky.

 

[joker9r]

The Baker web site is where I got the info... Sprockets & Pulleys | Baker Drivetrain click the tab for steel pulleys

 

[standuprick]

I havent done it on my mastiff. But, all my sportbikes I have always went down -1 in the front for better torque and low end. You dont notice much on the top end loss. On a sportbike -1 is like going +2 to +3 in the rear. The front should be cheaper. It still the same basic principal.

 

[pknowles]

I'm looking for any feedback from folks that have reduced there transmission pulley to a lower tooth count. What tooth count did you go with and what Negative or positive results did you get. I'm looking at reducing to a 31 tooth but I don't want to loose too much top end so I may just do 32. Here are the numbers from Baker...

Pulley Tooth Count>>>>> 29______30_______31______32______33______34
Wheel Torque Incr>>>>> +10%____+7%____+3%______0______-3%____-6%
Cruising RPM in 6th>>>> 3017_____2916____2822____2734____2648____2573

Buy an older Harley, they scream at 70 mph

 

[joker9r]

I havent done it on my mastiff. But, all my sportbikes I have always went down -1 in the front for better torque and low end. You dont notice much on the top end loss. On a sportbike -1 is like going +2 to +3 in the rear. The front should be cheaper. It still the same basic principal.

My last sport bike.. ZX9R... I went down -1 front and up 6 on the back. :2thumbs: I didn't use it for much over 55mph and at 55 I was screaming at about 5500 rpm.