spline issues

General
1

A couple of weeks ago I started a thread about the pros/cons of spline set-ups compared to square tapers.

That revolved mainly around the strength aspects i.e. splines being much stronger and whether that extra strength was needed for some types of riding.

Reading this : -

http://www.unicyclist.com/forums/showthread.php?s=&threadid=30950

and some others about problems with splined set-ups it occurs to me that complexity and ease of maintainance are also an issue: -

For me, I really do prefer to have a good understanding of any mechanical things I use, and be able to adjust them with a minimum of tools; generally I’m happy to have a lower performance if it means that I can fix the thing myself.

Obviously this aspect is irrelevant to those who really do need the extra strength of a splined set-up as they can’t use the simpler alternative.

I guess I see two issues here: -

  1. this is another factor to mention when advising beginners queries; I feel that on this forum there can be a bit of a knee-jerk response that splined=best, which is not true for many riders who are never going to be doing big drops etc (I acknowledge though that it’s impossible to predict whether a beginner will end up doing big drops).

  2. are some splined set-ups turning out to be especially reliable or unreliable? This would be useful in deciding which splined set up to go for.

2

I’ve seen the comments on spline problems too.

When someone has a spline problem, it would be nice to know what size drops they have been doing and how much they weight (and roughly how good there technique is).

Why? Because the energy involved in the impact of a drop is proportional to both the rider’s weight and the height of the drop. E.g. given equally skill, a 100lb rider dropping 8 feet puts the same stress on a uni as a 200lb rider dropping “only” 4 feet.

3

There are two areas of concern for splined hubs:

  1. How the spindle is secured in the hub body (usually a keyway)
  2. The crank design and the spline design for the cranks

The KH hubs seem to have a better keyway interface. After seeing Steve Howard’s disected KH hub it does look like the keyway design is better than Profile or Onza.

For crank design the Profiles are better. Profile cranks are strong and take abuse well. Profile cranks are also available in more crank lengths than other splined cranks. For the people who are really abusive they have the heavy duty Dirt Jumper version of their cranks.

The KH cranks are only available in two sizes (140’s and 170’s). They have some ergonomic issues (a nub that can get your ankle). And they seem to get bent more easily than other cranks.

Profile has a single simple keyway that is prone to developing slop.

There isn’t the perfect splined setup yet. All of the splined designs have their own individual issues.

If Profile could improve the keyway design so that it wouldn’t develop slop then they would have a very very good hub worthy of its premium price.