Welcome to the Yamaha Star Bolt Motorcycle Forum

Why join our motorcycle community?

  • Membership is free and easy
  • Get technical support and information for your Yamaha Star Bolt motorcycle or search for information before buying
  • Use the member map to find riders near you
  • Participate in our monthly virtual bike show (or at least vote)
  • Get rid of these annoying boxes asking you to register  ;D

More importantly, make new friends!!

Author Topic: Fork Tube Length  (Read 1205 times)

0 Members and 1 Guest are viewing this topic.

Offline srinath

  • Hero Member
  • *****
  • Posts: 815
Re: Fork Tube Length
« Reply #15 on: April 24, 2020, 01:54:56 pm »
Lower trail is just lower effort. And extra foot of wheel base will add well several feet at turn radius. But, really this isn't a lawn mower that needs to be 0 turn or else its gonna take you 10 more mins to mow your yard.
Turn radius on the road always is higher than the lowest possible at lock types.
And on the road turn radius and turn speed are determined by tires more than much of anything else. Maybe ground clearance and suspension come in at #2 and 3.

Anyway the lowering of trail on the savage, and reduction in rotating mass (aluminum front wheel) and reduction in Kinetic energy of rotation 21" spins slower than 19" at any speed made for a bike that steered effortlessly, compared to the stock overloaded wheel barrow the savage feels like for the most part. It wasn't faster - slap identical tires on it and run it with a savage of the same weight, you'd not go any quicker, likely not much slower either unless your run included a U turn in a single lane width.

Anyway that's for a savage - on a bolt, its so heavy, and its steering effort is pretty low considering its weight, its not a bike you can improve upon to start with. But longer forks and different wheels - make it better ? or worse ? Depends on a lot of factors like axle offset, wheel diameter etc etc.

Your turn radius on the road may not even be affected by this, speeds at turns are determined by tires and some sizes of tires are far better for availability and $$$ to performance, but well, outside of that its pretty much unknown.

Oh no - This has turned into a Srinath-Lunkhead thread again. I'm saving Del-Pete's typing here.

Cool.
Srinath.

Offline lunkhead

  • Hero Member
  • *****
  • Posts: 1616
Re: Fork Tube Length
« Reply #16 on: April 24, 2020, 03:36:18 pm »
Not sure what you mean by turn radius. Full lock on the steering is as tight as you can get on any bike. Before shortening the trail on the Bolt, it would be wise to install tapered steering bearings. Going with more trail will require more effort to initiate a turn but it won't keep you from leaning as far as you want. The bike will just want to go straight so countersteering needs more persuasion.
C-SPƎC

Offline lunkhead

  • Hero Member
  • *****
  • Posts: 1616
Re: Fork Tube Length
« Reply #17 on: April 24, 2020, 04:01:24 pm »
Those crazy Japanese got it all figured out.

https://m.youtube.com/watch?v=dEYEn_fpv-4
C-SPƎC

  • Advertisement

Offline srinath

  • Hero Member
  • *****
  • Posts: 815
Re: Fork Tube Length
« Reply #18 on: April 24, 2020, 05:08:49 pm »
Not sure what you mean by turn radius. Full lock on the steering is as tight as you can get on any bike. Before shortening the trail on the Bolt, it would be wise to install tapered steering bearings. Going with more trail will require more effort to initiate a turn but it won't keep you from leaning as far as you want. The bike will just want to go straight so countersteering needs more persuasion.


No I am not talking about on a stock bolt. I'm talking raked out bolt either by longer forks, or degreed triples and longer forks etc etc.
I was comparing - quite basically just longer forks vs longer forks and trailing axle as an option and more so a raked triple set, longer forks and trailing axle - flipping a dirt bike forks left to right.
Yea Jap bike designers figured out what the club racers of the 60's in England always knew LOL. Near 0 but positive trail for effort, shortest wheel base for quickest turns @ full lock, and steepest rake for quickest handling - if you dare. Consequence is - it will move before you think - think wrong and you're done.
Will watch that video in a bit. Bandwidth is currently eaten up by skype for kiddo.

Cool.
Srinath.

Offline VIKEN

  • Jr. Member
  • **
  • Posts: 76

Offline VIKEN

  • Jr. Member
  • **
  • Posts: 76
Re: Fork Tube Length
« Reply #20 on: April 30, 2021, 05:59:48 am »
I'm going for a '70s Nor Cal chopper look. I want to get 6" over tubes.  I currently have 3" extension and like them but want a bit more.  I'm not comfortable with 3" more extended than I already have.  I'd rather just have the complete fork tube.  Franks Forks can make them but I need to know how long the stock ones are so that I know how long to order the new ones at 6 over that measurement.

I'm in this exact situation and been searching around. I might just go to a dirtbike front end swap from the looks of everything. How's your setup now?

that chopper "squat" (LM rear lowering bracket, +3" front fork extension)