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Author Topic: Question about Front Axel on some RE bikes.  (Read 375 times)

chinoy

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Question about Front Axel on some RE bikes.
« on: January 21, 2010, 06:04:24 AM »
Sorry if this is the wrong forum but its a generic question.
Ive noticed on my C5 as well as a few other Bullet models.

That the front axle is not placed under the front shock.
Rather the end of the front fork is shaped like a L and the axle is placed at the end of this L.

What is the logic of the this design ?
How does it effect the bike.
Why not just put the axell at the end of the shock like all other bikes ?


Vince

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Re: Question about Front Axel on some RE bikes.
« Reply #1 on: January 21, 2010, 04:24:59 PM »
     This allows for different relationships of rake and trail (steering geometry), and changes the engineering needed to get the rake and trail figures desired for the bike. This determines your basic steering characteristics. It also allows for an extra inch or more of suspension travel without raising the ride height of the bike.
« Last Edit: January 21, 2010, 05:37:59 PM by Vince »

ace.cafe

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Re: Question about Front Axel on some RE bikes.
« Reply #2 on: January 21, 2010, 05:07:07 PM »
It's been around a very long time.
It's called a "Leading Axle Fork".
Very common on motocross bikes, especially.
The Bullet has always had a small amount of leading axle geometry, and it was apparently increased with the new UCE forks.
It usually has the effect of reducing trail, giving quicker response to turning.

The old Bullet has about 4.75" of trail.
You could measure the trail on your C5, and see what it is.
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GeorgeE

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Re: Question about Front Axel on some RE bikes.
« Reply #3 on: January 21, 2010, 05:19:09 PM »
Just FYI Enfield also made fork bottoms for sidecar use in the 50's and 60's with different lenght of lead for sidecar use. Have never seen a pair so can't give dimensions. Probably unlikely to find a pair at this late date anyway
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Geirskogul

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Re: Question about Front Axel on some RE bikes.
« Reply #4 on: January 21, 2010, 06:55:23 PM »
Putting the wheel further forward than the fork tubes themselves greatly reduces the chances for a tank slapper to happen.  Leading fork was pioneered by both Harley Davidson and Brough motorcycles (it was around before them, but really took off with them) at the same period, and increased stability.

In fact, I remember seeing old-timey ads for Brough Superior that claim that the "NEW" castle forks or leading forks are what allow you to take your hands off of a SS100's handlebars at 100mph and it'll keep going true.
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motomataya

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Re: Question about Front Axel on some RE bikes.
« Reply #5 on: January 21, 2010, 07:04:51 PM »
If you move the  axel forward you will reduce trail making the bike easier to turn and less stable.