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Front fork problem

2K views 31 replies 18 participants last post by  Dream Catcher 
#1 ·
I dont know if this is the right board but it appears that my frt tire is closer to the shrod than it should be it is rubbing the fender extension on the shroud can some one give me some advice on this
 
#27 ·
Way back in 02, when the fender extenders were just getting popular....

I did some measurements and a simple model of the front fork geometry
on a cad system.

As the front fork compresses the clearance between the front wheel and the lower cowling decreases.
At full compression, the lower edge of the front fender is above the cowl
and the clearance is to the front tire surface instead of the fender surface.

Now, with a fender extender on, when the forks compress, instead of having a clearance to the tire surface, you only have clearance to the new fender extension. So there is a lot less clearance with a fender extender, when the forks are compressed.

Now, you have to add in another dynamic.
When you clamp on the brakes, even with anti-dive, there is some fork compression...
and if the front tire hits a good dip or bump at that time, it adds even more compression...
Now, add in the effects of a half ton of bike trying to push itself over the heavy braking front tire.
The fork tubes flex rearward a significant amount as they react to all the weight pushing against them.
The original configuration, without a fender extender, allows for the front fender to be above (and clear of) the cowling, under heavy compression and braking. When there is a fender extender, there is a range of motion in which that fender extender doesn't clear under compression, and it can contact the lower cowling when the forks flex backwards under braking.
One danger was if the lower edge of a rigid extension was not kept close to the tire.... it could jam on the cowling as the forks started to decompress.
You'll notice all the available versions keep the extender wrapped closely to the tires surface, even though it would give more
protection if it extended straight down from the fender.
 
#28 ·
There are fender extensions out there that are longer than the Honda ones - it is this type that hit the front cowl at the pointy bit when the forks compress and conditions are right.

You can remove the fender extension and take about 4-5 mm off and put back on or replace it with the Honda one. When refitting, make sure extension is up against the mudguard before tightening up.
 
#29 ·
Roaddog i am very sorry to hear you lost your daughter
thank you cycledude its still hard for me to get past it but i'm tring.
thank you again.
 
#31 ·
If things are properly installed, I honestly see no way a fender extension can hit the front lower cowl. I have the extra long one on my bike , the one with the internal braces on it .

No way that could hit the cowl even jumping railroad tracks. With the rake of the bike putting force on the stem bearings if they were loose or missing or fallen out at the bottom the forks would actually move to a more forward angle, not a reverse. Same with worn fork bushings to the extreme, with the weight of the bike the angle would increase more forward.

Mystery to me. I agree with the dealer fellow, never seen this before.

Kit
 
#32 ·
If things are properly installed, I honestly see no way a fender extension can hit the front lower cowl. I have the extra long one on my bike , the one with the internal braces on it .

No way that could hit the cowl even jumping railroad tracks. With the rake of the bike putting force on the stem bearings if they were loose or missing or fallen out at the bottom the forks would actually move to a more forward angle, not a reverse. Same with worn fork bushings to the extreme, with the weight of the bike the angle would increase more forward.

Mystery to me. I agree with the dealer fellow, never seen this before.

Kit
Put on the front brakes and the fork flexes back.
 
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