Facts:
1) I bought my last 4 bikes brand new and downshift DAILY.

2) All bikes went over 100K.

3) Only with my 2nd bike, the spline "rounded off" inside the spline hub so I lost all ability to go forward and was towed of course.

Note:
Now that my present bike is crossing 80,000 miles I am getting concerned I am once again going to lose my spline hub and have to be towed.

Yet it only happened once with the last 4 bikes.

Question:
Since it only happened once in 4 bikes, was that just a "1 off", an odd thing that happened. Or is it likely to happen again?

Thank you in advance for your opinion.

BuzzCap7

 

Using the engine to slow any gasoline powered machine is often destructive in many ways. It generally adds driveline stresses on the weaker side of the powertrain, contributes to increased oil consumption and offers almost no benefits except for the fun noise it makes.

 

I've been riding almost 50 years and well over half a million miles, always downshift and have never had that problem. If you do it smoothly that failure ain't your fault!

 

Downshifting is something I have used on every vehicle I have ever owned/driven, including semi-trucks, army trucks, delivery trucks, cars, vans, motorcycles, etc. I have never had an issue with downshifting, and it is taught and encouraged in some professional/military driving training.

If the spline is rounding off, it's from using it, not necessary from downshifting. I've read a lot of complaints about the spline rounding off, and I have no doubts about that happening, although I have never had it happen to me.

Keep on truckin' brother.

 

That is ridiculous.

The benefit of downshifting when slowing down, in addition to helping decelerate the bike, is that you will be in the correct gear for the speed you are going, and can accelerate easily if needed.

It does not harm the driveline or engine.

Some people never learn to do it properly, you can tell because when they slow down, they don`t match the RPM, they just drop down into the next lower gear and you will hear their rear tire chirp, or they just pull in the clutch and come to a stop, then start stomping on the gear lever to get the transmission into first gear.

OP: What part are you referring to when you say "Spline Hub", and what model/year machines are you talking about?

 

Dan, your post is my thoughts in reverse. I don't understand what "splined hub" is, I'm guessing compensator? I also agree that correct downshifting while matching rpm's to driveline speed is correct and should be practiced to perfection, with no negative mechanical issues. It should also be done in a gentle manor.

 

Spline Hub is what they said and was on my invoice. I may be able to find it if you like. From the engine, what sticks out is the spline. It looks like an oblisque (tapered conical thing) with splines. Splines being grooves.

(I am not mechanically inclined so pls bear with me.) What THAT piece goes into the HD service guys called it the Spline Hub. That turns the gears which turn the chain or belt to drive the rear wheel. Did I say it right? That make sense? I can draw a picture or see if I can fine the invoive.

It was a 2009 Ultra Classic.

Does that help?

BuzzCap7

 

It's a problem with the 06-up dyna 07-up baggers/softails.. I suspect it's mainly poor spline fit and the fact that they moved the primary drive sprocket out on the clutch (swapped position of starter ring gear and sprocket). If the fit is loose, they get uneven pressure and eventually shear. Tight fit helps..