Originally Posted by LA_Dog

Upgrade choice #3: 30t upgraded front belt pulley and 70t upgraded rear belt pulley- with the stock 133t belt!

Applicable to all 2007-up Softail / Dyna bikes with 24mm, 1" and 1-1/8" belts. 20mm belt bikes will work too you'll just have a wide gap in the pulley alongside the belt as most all 70t pulleys are cut 1-1/8" wide in the belt track.

>> Your stock belt guard will more than likely not fit without modification. Keep this in mind.

This 30/70 combo WILL WORK with the stock Softail / Dyna 131t, 132t, 133t belt lengths. There is just enough adjustment room to install wheel and adjust belt. Attached are rpm / mph graphs of stock 32/66 pulleys vs 30t/70t pulleys from 3k rpm and up. This is actually an easy upgrade as long as you have the right parts ready to go and are familiar with removing / reinstalling a rear wheel. Cost will be determined by the expense of your 70t pulley if you already have the 30t front installed- otherwise you'll need to factor that cost in as well. Bolts & pulley offset spacer is about $30 total. Always use at least Grade 8 pulley bolts and NEVER re-use old pulley bolts.

By going to a 30t front and 70t rear pulley combo, you end up with a net 13% improvement in rear wheel TQ and drive ratio. That is significant and absolutely seat of pants noticeable over stock. However, you still don't get much penalty in freeway rpm. You'll be about 300rpm higher at 80mph vs stock.

Speedometer correction setting: 2392 for the Breakout with 240 tire. For all other model bikes, just add the ratio percentage increase to your current value. For example, with a 30t front pulley and 70t rear pulley, it is a 13.1% ratio increase. Multiply your VSS by 1.131 to get the new VSS number. fine tune with a gps as needed. Lower VSS by 10 if speedo reads slightly too fast, add 10 to VSS if speedo reads slow. adjust in increments of 10 as needed and re-test. With my Pirelli Night Dragon 240 rear tire, I ended up with 2362 for my accurate VSS number. the diameter of the rear tire is considered in the VSS calculation.

Here is the gear ratio, rpm, mph results for the 30/70 belt pulley combo: charts courtesy of http://woodsware.aciwebs.com/gears/




HD 70T factory pulley HD part numbers - This will work with all Softail / Dyna with 20mm, 24mm, 1" and 1-1/8" belts:

>> Dyna will need an additional 1/4" pulley offset spacer so the top of belt does not contact frame when suspension is compressed
>> Softail Breakout and Rocker will need an added 1/8" pulley spacer so belt does not rub tire when walking bike backwards 10ft or more, especially if you are running a 260 tire.

1. 2004-2006 touring FLHT 70T, 1-1/8" wide rear pulley. HD part # 40217-04, cast part # 40117-00
Should fit all 2001-up bikes, 2.25" standard pulley hub.

1A. 2006 FXDB (black) 70T, 1-1/8" wide rear pulley: HD PN# 40576-06. it's 1.125" wide. The pulley itself is stamped with 40581-06

Bolts
For #1 above, you may need slightly longer or shorter bolts than your present stock bolts. You only need to be sure the bolt thread is able to screw into the wheel hub a minimum of 1" and ideally 1.25". All bolts for all wheels are 7/16" 14 thread by varying length. So if your stock bolts are 2-1/4" long then you may need 1-3/4" length bolts instead.

For #1A above, your stock pulley bolts should work. But get a new set of bolts at dealer, DO NOT RE-USE BOLTS!

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Aftermarket Billet Pulleys (PM, Ness, DNA, SMC, etc):

Good custom source for 70T billet rear pulleys, prices not bad and they make custom pulleys for any bike: http://www.southern-mc.com/coblsppu.html. Riders with 20mm belts can order the pulley in 1" width.

Arlen Ness - any pulley designed for 2004-2006 FLHT Touring or 2006 Dyna
Ness Black contrast cut models: 16-531 16-950 16-970 16-990 16-976
Ness Chrome models: 16-629 16-501 16-940 16-960 16-980 16-627
Ness Catalog ref: http://issuu.com/arlen_ness/docs/2012_hd_issuu/45
Performance Machine - any pulley designed for 2004-2006 FLHT touring or 2006 Dyna, 70t - !!important note on ALL PM pulleys- the outside hole of the PM pulleys are too small to fit the stock axle spacer. PM wants to sell you a fancy spacer that fits. But, all you have to do is get your stock spacer turned slightly narrower in diameter by a machine shop. You will turn the inside half of the spacer (the side without the two lines on it) smaller in diameter until if fits through the PM pulley opening and has .008 to .010 of a gap.

Other brands of pulley such as DNA, RC Comp, etc can work as long as they are spec'd for the same year model fitment as above. All of these 70T pulleys will be: 1-1/8" belt width, 70 tooth count, 2.25" wheel hub hole, and you WILL need to buy the proper pulley offset spacer. Billet pulleys do not come with the offset spacer molded on like the stock HD pulleys.

Offset spacers:

>>For Softail except Breakout, Rocker: You will need a .250 (1/4") spacer (Drag Specialties pulley spacer for Harley 00-15 2.25" ID model 7805-5051). If you are running a custom wide tire you can get a 3/8" or 1/2" spacer instead for the added tire to belt clearance.

>>For Breakout and Rocker, you will need a 3/8" spacer, especially if you run a 260 tire. this will prevent the belt from rubbing tire when walking bike backwards.

>>For Dyna, you will need a 1/2" spacer so the top of belt does not hit the frame when suspension is compressed.

More bolt info:
Bolts for Arlan Ness pulleys - Need five 7-16" x 1-3/4" 14 thread round head socket cap screw bolts, at least grade 8.
Or, Harley Davidson 7/16"-14 x 1-3/4" hex socket cap head Screw P/N 3542 - hard to find / discontinued. Any bolts purchased should meet or exceed Grade 8 alloy steel. DO NOT use stainless steel bolts.

Good source for cheap high quality bolts - see pic below of bolt bag for company info. they sell small quantities on ebay or direct. Also Zoro or Grainger.

Bolts for Performance Machine pulleys - Same as your stock flat 5 point Harley bolts.

Bolts for other brand of billet pulleys: If the pulley bolt holes are slightly countersunk and round, get the round socket head bolts. If the bolt surface is flat, get the regular 5 point bolts.

For any bolts you buy, you MUST get them long enough so you have 1" to 1.25" of bolt thread going into the wheel. DO NOT use a bolt that has less than 1" of thread going into the wheel. The bolts are the ONLY thing keeping that pulley on and bolt failure can result in death or serious injury.

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Pulley fitment summary:

I suspect that any 2000-newer softail/dyna 70T pulley that is 1" to 1-1/8" wide will work fine on any other 2001-up bike that runs a 1", 1-1/8", 20mm or 24mm belt- the bolt pattern is same and the hub seat diameter is same on all bikes without IDS (cush drive) from 2000 to present. The only thing you may need, like the Breakout and Dyna owners, is an added wheel spacer and longer bolts. All HD pulleys have a 1/4" spacer actually molded on to the back of the pulley and this offset is good enough for most bikes. Aftermarket billet pulleys assume a custom build and you will use the correct offset spacer.

Dyna owners usually run a 1-1/8" wide belt so be sure to always get a 1-1/8" wide pulley. Most all available 70T pulleys will be 1-1/8" wide. If you have a 20mm, 24mm or 1" wide belt it is ok to run a 1-18" wide pulley.

To put it another way: You can buy any of the chrome design HD or aftermarket billet (RSD, PM, BDL Ness etc) 70t pulleys for a 2004-2006 FLHT or 2006 Dyna - or really, any other 2000-up 70t pulley for HD or custom choppers, and fit it on your current bike. As long as the pulley has the 2.25 hub hole for 2000-up softail/dyna bikes without IDS (cush drive) and is 1" to 1.125" wide (so it fits your belt) you're probably good to go. Worst case you will need a thicker offset spacer and longer bolts. that's pretty much it.

The five hole bolt pattern and bolt type (7/16" 14 thread per inch x needed length) is the same on all non-cush HD's and the axle size or axle spacers do not matter for the pulley (the pulley bolts to wheel hub and never touches axle or wheel spacers).

Once you have the pulley, you would only need to determine the appropriate hub offset spacer and length of bolts- which is not hard to do. Once you have the parts this is no more difficult than replacing a rear pulley.

I wanted to stress these facts so the thought of swapping to another pulley from another year / model of bike does not feel too challenging.

The Breakout belt and many other current model FXS/FXD belts are 24mm wide - 0.98" - So it is fine to run a slightly wider pulley as long as you don't mind seeing a 1/8" gap on inside edge of pulley. Mechanically it is ok though.

Nine large PICS below so let them load:

Arlan Ness pulley #16-531 for a 2004-2006 FLHT (70t, 1.125" wide), Drag Specialties 1/4" pulley spacer, industrial Grade 10 round head socket cap screws 7/16" 14 x 1-3/4"
(you need at least grade 8 for pulley bolts)
Order pulley bolts from American Integrated, phone number is on the 2nd photo (bag of bolts). Best price you'll find and ultra high quality. They have all lengths / sizes.

What I did for this experiment is install the Arlen Ness billet pulley mentioned above, a 1/4" pulley offset spacer from Drag Specialties and five 7/16" 14 x 1-3/4" grade 10 pulley bolts.

I took some pics of parts and the measurement process I used to determine my offset spacer thickness below. Final measurement checking shows that the Arlan Ness pulley with the 1/4" spacer is within 1/32" of the stock pulley height offset. The wheel bolt length was determined based on the thickness of the pulley bolt seat (1/4") and spacer (1/4"), and the need to have 1.25" of bolt thread into the wheel.

Note that if I were using a stock HD pulley like from a 2006 Street Bob or other dyna (also a 70t pulley, 1.125" wide), I might not need the offset spacer since HD molds the spacer into their pulleys. This is why the 2004-2006, or 2011 68T sportster XL1200 pulley is a direct bolt on to other Dyna / Softail bikes even for the Breakout.






DS spacer placed onto backside of Ness pulley:


New round head 7/16" socket cap bolts for pulley - should sit nicely in there.


Measuring and checking pulley offset - stock pulley on stock wheel. lay straight edge across pulley face and measure from ground up to top outside edge of pulley.
your new pulley must sit at that same height so you would get the appropriate thickness spacer to push it outward.
in this case I needed 1/4" and the DS .250" spacer was $9.95


remove stock pulley, place spacer onto wheel hub


place Ness pulley onto wheel, on top of spacer. hold with a couple of bolts.


side view of DS spacer between pulley and wheel hub


checking offset measurement of new pulley and spacer- in this case I am within 1/32" of the stock pulley outward measurement. not bad.


::Everything installed great- no issues - :: - More pics below of the finished install::

UPDATE March 2017 -
Added info from member Dave0176 - He did the 30/70 gearing on his Custom (2009 FXSTC) and it came out awesome.
Link: https://www.hdforums.com/forum/softa...l#post16004484
Here are the parts that he bought for the DIY conversion and should be applicable to all softail 2007-up:

25700337: black inner primary gasket set
83595-11: Tri Glide front pulley
40617-06: 2006 Night Train 70T 20mm rear pulley (you *must* buy the 1/2" pulley spacer to use this specific pulley, since this is one of the few pulleys from HD that has no spacer molded on).
17369-06: primary gasket kit, comes with all seals
9231: Inner primary bearing
Drag specialties 1/2" pulley spacer (for the pulley, as noted above)
*Don't forget the appropriate length rear pulley bolts!

Originally Posted by IceChild

I did the 30t/70t to my Fatboy S. Along with the 117 kit, 2 into 1 exhaust and aftermarket air cleaner. Its a torque monster. Wheels and Pulley are from Southern Machine. I do have one question though. What lower pulley guard can I run that will be a direct bolt on, or will I have to modify one to fit?

Originally Posted by iaminsider

Question for all of you folks who did a 70T on a late model Dyna... Was a spacer needed for the rear pulley (40117-00 04-06 touring)? If it was, what size? I want to get the spacer ordered if it is going to be needed.