Our bikes have the tallest gearing that H-D ships. H-D transmissions are 1:1 in high gear, so it's the pulleys on the drive belt that make the difference. We have 32/66 tooth pulleys. It is said that our bikes are built this way to reduce noise and emissions.

I find the lower gears off just a bit. I ride through a lot of small towns where 3rd is just a touch too tall and 2nd is too low. On the highway (not interstate) I am shifting between 5th and 6th a lot. 6th is too high and 5th is too low, however, 6th is a great gear to run high speed on the interstate.

We can change a late model softail to a 30/68 pulley set using H-D parts, keeping the same drive belt. This makes the gearing near perfect. It adds 10% more torque multiplication in each gear and is great fun to ride. The only downside is you loose that high speed cruising gear.

Baker DriveTrain makes a 7 speed transmission, the DD7. It's 1:1 in high gear like stock H-D transmissions and I never thought it made much sense because I wanted an overdrive on older bikes. AhHa....our bikes are geared so tall they already have gearing as tall as overdrive.

Sixth gear with the pulley swap is the same as sixth gear with the DD7, however, with the DD7 you can shift up one more time when out on the interstate. Sweet. The DD7 also reduces the huge step from 1st to 2nd gear. Second gear will be great now on those really tight switch backs in the mountains. The upper gears are spaced closer together because you can't rev to high rpm in 5th or 6th to shift and stay anywhere near the speed limit.

There is a long "sticky" post on the older Softail Forum titled "Drive Ratio Upgrade....." that discusses the pulley swap: Drive Ratio Upgrade

I made a chart so you can compare the stock set-up, to the pulley swap, to the Baker DD7. The charts are based on the measured torque of my 2019 heritage 114 Stage II. Each gear line has data points from 2000 to 6000 rpm at 500 rpm increments. If you shift where the torque lines cross, you will get maximum possible acceleration in each gear (remember all these curves are at WOT). I labeled all the 3000 rpm points with their corresponding speed in mph. The left side torque axis has a Log scale to it, that keeps the gear lines equally spaced if the percent ratio change between gears is equal. Comments?


Softail Gearing Comparison

 

I've been reading about the DD7, looks pretty good: DD7 Transmission Kit
And a couple install videos below. Another excuse to buy more tools.

Part 1

Part 2

 

Damnit, now I want a 7 speed transmission.

 

I've ridden quite a few miles on a 7 speed GoldWing DCT. Seven speeds are pretty nice.

 

The DD7 would be a phenomenal upgrade all around. I clicked the link their website is a good read informative & concise. $3400 just for the parts means most won’t do it but doubt anyone who does would regret it.

A sprocket & pulley change is a great improvement in the bang for the buck department though. I think for anyone with a stock cam the 30/68 is a great choice. For me with an upgraded cam 3,500 peak torque vs 3,000 for the stock cam, I’ll go 30/70. Better acceleration & more optimal gearing for the cam at no extra cost.

In top gear 80 mph cruise speed is still only 3,300 at or slightly under peak torque and in the meat of the torque curve for most common upgraded cams.

5,800 rpm WOT upshift into 6th occurs at about 120 mph IE still well past the 1/4 mile mark for most of our bikes. So anything taller only leaves more & quicker acceleration left on the table for no appreciable benefit.

In my example a stage 3 holds peak HP to 6,200 that’s 150 mph. To say 60 mph a 30/68 or 30/70 shouldn’t use any more fuel than stock gearing. You just accelerate & upshift quicker when using the same throttle twist.

The 30/70 1 to 1 final drive ratio is still only 3.15. In my youth the cars had 3 speed transmissions with a 1 to 1 final drive ratio. A 3.15 gear would have been considered a good all around gear ie between a highway fuel economy gear and a performance or acceleration gear. It applies to our Harley’s today. The stock 2.79 final drive ratio is a maximum highway economy gear. A reasonable sprocket & pulley change should make for a much quicker and all around better bike and riding experience. Food for thought for any Harley riding enthusiast.

Also FWIW anyone with greater acceleration and or power goals should consider a chain conversion. Belts are great but have more limitations with regards to strength & gearing.

 

On my 14 Softail I bought a Sportster rear sprocket which changed the gearing to the same as the touring bikes. Not a huge change but one that was noticeable. Used stock belt. Didn't even need any spacers for the sprocket change. That is by far the cheapest way to go. But to my knowledge no one has done it yet. So not sure it will work on the M8 models. I used my power vision tuner to calibrate the speedometer. Hoping someone will give this a try and let us know the results. Thanks for the research and starting the thread.

 

Good post Hulkss it is a yarn we needed to have , I have similar issues where my 3rd and 4th in the twisties could use a bit of gear ratio thought.I was thinking of going to a 31 tooth countershaft and keeping the stock R pulley but that might make my wheelbase too long. I am thinking of an RS468 cam in the very near future ,I was going to go a big bore at the same time BUT my piston and ring seal still shows very clear oil after 3 services and 11000 miles and using no oil at all, so I'm not going to upset that by a teardown , so yea an RS468 before or after Xmas then a big bore in a year or two.
Hulkss this 68 rear pulley what M8 does that come on ? is it a HD part.I think 30/68 is way too low for me but 31/68 would be just lower than stock and with a left side cam could be the goods.
I think for you is the 7 speed myself, it looks like what you want. Going to watch the MotoGP qualifying now BBK soon.
Cheers.

Peace.

 

The chart I made in the first post is my attempt to show in the numbers, what you will experience on the road with a gearing change.

Stock overall ratio in 5th gear is 3.307, stock 6th gear is 2.790. The 30/68 pulley change puts 6th gear midway between stock 5th & 6th.

A quote from another forum by gabbyduffy: "I have to set the record straight for anybody that happens to read this post looking for info to decide which pulley to use the 30tooth or the 31tooth (with 68t rear). I spent over 6 months riding with the 31tooth pulley and after a couple of speeding tickets and constantly shifting from 5th gear to 6th gear on the freeway, I went back to the 30tooth pulley.
I had to learn this the hard way, but the 30tooth pulley is a much better choice for the 09 and up Harley's. After experiencing both pulleys....."

Touring M8's have a 68T pulley, but, it won't fit a Softail because it is cush drive. The parts to get are:

40444-07 rear pully 68T from a Sportster
83595-11 front pulley 30T from a Trike
3899 pulley bolts, to work with the Sportster pulley

A 68T rear pulley will hit the belt guard unless you put the 30T up front to get the axel back in the stock position.

Lots more info and discussion in the thread I linked in the first post.

 

Unfortunately the 83595-11 nor any other 30 tooth sprocket will fit the M8. What the mechanic called the input shaft is too small in diameter. Stood there and watched him try to fit it. A possible solution might be if someone would machine and weld an adapter to the 30 tooth sprocket. Until then the best we can get is a 31. My scoot is a 2019 but I would assume all the M8's have the same input shaft. Have not tried to calculate out what the 31/70 will provide as far as a final drive ratio. Certainly its a bump in the right direction. The only other somewhat reasonable option I know of is to convert to a chain. There is also a chain that goes from the engine to transmission but I have not looked into that.

On the pulley if you can find a used 68 from a Sportster that could be a good budget choice as to buying a new pulley. Pretty bummed about no 30 T. Be cool if someone could machine a batch of adapters to fit a 30. But I don't really have any idea about the practicality strength longevity of welding some type of adapter to a cast pulley.

 

That's weird because according to the parts diagrams an M8 trike comes with that part.