Knurling fork tubes

[zrx1100]

While watching the cycle world podcast on handling (

) came accross this bit at minute 11:45 where they say one of the tricks to improve handling on XS650 is to knurl the fork tubes where they are clamped by the triple trees. Anyone has feedback on this idea?

 

[AndersJ]

Hmm. I think I’ll try it and report back. Winter is here…Tis the season for d*cking about.

 

[WideAWAKE]

While watching the cycle world podcast on handling (

) came accross this bit at minute 11:45 where they say one of the tricks to improve handling on XS650 is to knurl the fork tubes where they are clamped by the triple trees. Anyone has feedback on this idea?

Interesting…

I’m not sure what it would accomplish, unless his tubes were spinning to begin with???? Or his triple trees were worn and he wanted a tighter clamp down??

OR… he wanted to find the biggest suckers on the track and spread a rumor he did it haha. See who might waste their time chasing dragons.

I don’t know of any modern bikes that use it.

 

[AndersJ]

Nor do modern bikes use spindly forks so it’s apples to oranges…I think the question is do the forks rotate with force applied? And if so, will addition friction stop or reduce them from rotating. I say why not.

 

[WideAWAKE]

Nor do modern bikes use spindly forks so it’s apples to oranges…I think the question is do the forks rotate with force applied? And if so, will addition friction stop or reduce them from rotating. I say why not.

Spindly??? I do not follow.

 

[AndersJ]

Spindly??? I do not follow.

As in thin. I would think modern forks which are thicker and provide more surface area for a clamp would be less prone to rotating. I’m also not an engineer. I do enjoy chasing the occasional lizard though.

 

[Max Midnight]

IMO snake oil.
Assuming the tubes are correctly torqued at the four points on the yokes then there would need to be a very large axial force applied to the wheel.
Even with serious off roading unlikely but not on the street.
If the tubes were able to rotate in the yokes then I would expect to see some evidence of this.

As stated previously, if this were an issue then manufacturers would have adopted it.

 

[zrx1100]

Back in college, I ran off the road in a turn on an xs400 and went down. More of a spill in the dirt than a crash. The forks were twisted quite a bit. Straightened them out somewhat by pulling on the bars while holding the front wheels with my legs. and rode home. Upon inspection, the tubes were perfectly straight. Just twisted. It does not take that much twisting to create unease in a fast corner. What I wonder is why knurling vs a fork brace? Weight?

 

[gggGary]

My In general knurling is a stop gap to reduce clearance in worn out parts. it will reduce the contact surface area. It MIGHT be effective with the softer aluminum top triple but doesn't seem like it'll help with the forged steel lower.
My experience with XS650 forks (and most other bike forks as well) is if the fork is tweeked Ie handlebars not aligned with the wheel, the tubes ARE bent. It can be pretty subtle but shows up with gggGary's are my forks bent ;^)

or in the lathe or Vee blocks.

Lower triples are prone to getting tweaked/bent also.

 

[WideAWAKE]

As in thin. I would think modern forks which are thicker and provide more surface area for a clamp would be less prone to rotating. I’m also not an engineer. I do enjoy chasing the occasional lizard though.

Sooooooo not apples and oranges… just two different kinds of apples.

 

[mrtwowheel]

IMO, this is a joke. Everyone knows that in order to achieve the BEST handling the fork tubes must be welded to the trees.

 

[DaveO]

"gggGary's are my forks bent"

Genius.

 

[Max Midnight]

Back in college, I ran off the road in a turn on an xs400 and went down.

Methinks there is a difference between the force exerted on the forks during 'normal' riding and when your talent runs out and you put it down.

 

[arcticXS]

Makes me wonder if using something like Loctite bearing locking compound may work?

 

[zrx1100]

A good point from the Facebook group

 

[bosco659]

My In general knurling is a stop gap to reduce clearance in worn out parts. it will reduce the contact surface area. It MIGHT be affective with the softer aluminum top triple but doesn't seem like it'll help with the forged steel lower.
My experience with XS650 forks (and most other bike forks as well) is if the fork is tweeked Ie handlebars not aligned with the wheel, the tubes ARE bent. It can be pretty subtle but shows up with gggGary's are my forks bent ;^)

or in the lathe or Vee blocks.

Lower triples are prone to getting tweaked/bent also.

Great tip on checking for bent forks!

 

[jetmechmarty]

I had to put mine on a lathe and use a dial indicator to find the bent tube.

 

[RC4MAN]

May work, may not, what you will do is ruin the chrome and create a place for rust to start when they get wet

 

[dave_a]

Knurling is a poor man's spline?
Almost every time I fell off my Yamaha Enduro (frequently), I had to tweak the front tire back straight again. The forks moved very easy. Too easy?
I could imagine knurling might make a difference in feel on a race track, where forces are extreme.

 

[zrx1100]

May work, may not, what you will do is ruin the chrome and create a place for rust to start when they get wet

A very good point