Nice work, LA_Dog!! This really opens up a new frontier for Breakout riders who are trying to eliminate the "anchor effect" of the stock gearing. This entiure sub-thread should really be made into a sticky. It is pure gold.

Just to clarify: which FRONT pulley do you currently have mounted? (so that others who want to do this clearly understand whether it works, without changing the stock belt, with a stock front pulley or a smaller (e.g. Trike) pulley).

Jim G

 

I'm going to start a new thread just on this topic- e.g. going 32/68, 30/68, 30/70. I agree this is a real breakthrough to be able to do this for a 13% improvement in gearing. And this would apply equally to all current FXD/FXS bikes. I have the 30t front tri-glide pulley installed and stock 133t belt, and now the 70t rear pulley.

Can't wait to take her out for a spin- My only final concern would be a potential increase in vibration at highway cruising speeds. But maybe not- the 70t billet pulley is larger in diameter but actually much lighter.

 

here are the stock 32/66 speeds in mph for each gear 3000 rpm-up, and new projected speeds in mph based on 30/70.

 

first pass at starting new thread. please add info as you see fit. let's make it a good, overly informative thread on this topic. http://www.hdforums.com/forum/softai...p-to-13-a.html

 

New pics of the 70t installed, and the install process, are up in the new thread! lots of pics so please let page load. https://www.hdforums.com/forum/softa...p-to-13-a.html

 

Update!

I just went for a 20 mile ride today with the new 30t/70t combo - through the canyons and some freeway. Freaking excellent. 3rd is much more of a wide range gear now in town and canyons. 6th is still smooth and when you roll on it in 6th, the bike actually goes somewhere!

When I twist the throttle in any gear it is like "right now" instead of "thinking about it". I don't feel like I am shifting too soon or anything- but i do shift sooner through gears on hard throttle because well- the bike is getting up to speed that much faster .

Actually the bike now feels "normal" compared to my Big Dog Evo 107 with Baker6, and previous older HD's I've ridden. The Big Dog came with 3.06 overall gearing as standard and older HD bikes were about in the high 2 to low 3 range.

Granted- the biggest noticeable change difference will be going 30/68 from the stock 32/66. Completing this upgrade experiment with the 70t on the rear gave me the perfect added bit. So I would say that 30/70 is optimal for a performance-oriented rider and town bike.

Belt tracking is good- checked it constantly. no issues. i rolled the bike backwards 50 feet and the belt tracked to the inside edge as normal. no belt rubbing on tire. all good.

Gratuitous photo from today: Happy happy!!

 

Excellent, LA_Dog! Congratulatiosn on carrying through to full and successful execution.

How does the engine feel running at close to 2500 rpm in 6th gear?

Did the correction of the gearing factor in the ECU result in an accurate speedometer and no ABS difficulties?

It will also be useful to watch the mpg with the new gearing. Although the new gearing SHOULD hurt the mpg somewhat, the degree is questionable, since the bike is geared "too tall" to begin with. The drop in mpg might not be much.

I currently average 44 mpg with stock gearing and a 220 b (with riding gear) rider, when riding mostly highway with relatively fewer stops. The mpg dips to as low as 39 when doing "suburban metro" riding.

Jim G

 

Hi Jim thanks for your input on this. There is no difference in smoothness I could discern. and I was extra vigilant on this ride looking for any minor differences. only thing I noted is slightly better range of usable gear in 2nd through 4th versus the 68t pulley- which is a good thing in town. if you are at say 1900 rpm in 2nd and gas it a little bit, with stock 32/66 gearing you bog. With this gearing you go!

If you check the rpm vs mph chart on the gearingcommander.com site- or I think post #4 here, you'll see it is only a few hundred rpm difference (13% right?) in 6th.

For MPG- this gearing change by itself would not impact mpg in any significant manner- except it may cause you to punch it alot more often now, and yeh your mpg goes down the tube. heh.

seriously though, your tuning / fuel map and right wrist will help or hurt mpg more than anything. but I'm not telling you anything new. I'm going to revise my target AFR map to have a higher econ rpm range (14.2) at lower kpa. before, I was cutting off the economy range at 3000 rpm. I'll take it up to 4k rpm at 30-60kpa. actually, maybe 3500 would be sufficient since that is still 85mph or so in 6th.

{edit} speedometer seems correct with the new settng of 2392. I'll have to chrono it with my gps to be sure. I don't have ABS on my bike (2013), but I don't see any reason why it would be affected at all.

You're next on the list to do this upgrade bud!

 

With my post-retirement income stream, this requires some spousal concurrence.

And remember, I have no garage, a 7% grade driveway that is also gravel (slippery and dusty caliche to be more accurate), and only a 6x12 enclosed trailer that is assigned a grossly UNlevel (sideways tilt) storage location by my landlord, so I will likely have no choice but to pay someone to do the work in their shop.

But yeah, if I can get my dear wife's financial blessing, and figure out how to physically get it done despite my lack of a suitable workspace, I'm sure game to do it!

I remember how my highly modified 375 lb all-carbon fiber Ducati 916 Monster felt after I steepened the gearing by about 18%. It was an absolute rocket, and I had trouble keeping the front end down in the lower gears, even at highway speed.

Jim G

 

LOL!! You do have some challenges there sir! But given everything else you've managed to accomplish I have full faith in ya

Monster -great bike. must have been a real handful after the gearing change. I did something similar recently to my YZ 426- dropped the gearing 20%, that thing was nuts. roll on in 3rd and wheel stands right up. Just recently sold it to a guy who was going to super-moto it. My 426f actually had street legal registration and plate which is rare for a straight dirt bike.