Tech advise on front end geometry needed

Energy One
JoeHawkins

JoeHawkins

Member
So, I busted my fork sliders. They grind and I tried for 3 days to seperate them to no avail. They had bottomed out once and I think internally they got screwed up.
Now I found a decent deal on the same sliders which are the Ultima 41 mm that BDM used on the husky models. For not much more, I could get longer ones. Like 4,6 or 10" longer. I don't think 10 would be a good idea but I would like to hear the members opinions on longer forks. Pros and cons.
 
S

Sven

Well-Known Member
Pro:
The more it's kicked out, the more stable a ride.

Con:
You have all this weight to twist as is the fork tubes are longer. See how a flagpole bends in the wind, so will more flex the more you add. Floppy yes, once upright it will steer slow.

Raised, it throws off the rake/trail geometry. Steering tends to flop over as you make slow turns. This makes you steer with more effort when in slow traverses.

More weight added to the front end.
More chance of topping out because you are going to use stock springs and spacers?
More stress on the fork pinch bolts as they tend to twist in the initial pull to center from a cocked, parked position.
More rise which sends the fuel level shorter as there is a rise in the front, less fuel before it hits the filler cap at that angle. If more horizontal, then the fuel level is across the top of the tank, not tilted up some and there goes less volume heading into the tank.
 
JoeHawkins

JoeHawkins

Member
@liferider '02 Husky

@Sven Some pretty good points. Just that there is no fuel lever. And I'm not sure what you mean by floppy and or flop over.
 
FrankBDPS

FrankBDPS

Well-Known Member
Go to American Suspensions web site. They have an explanation of front end geometry there. I am not a big time mechanic but I would put it back the way it was. By flopping they mean it would act like the front wheel on a screwed up,shopping cart.
 
JoeHawkins

JoeHawkins

Member
Ewwww.... Yea, no need for that. I'm going to try one more thing to seperate them to see what can be salvaged. Going to use a length of capped off pipe that fits over the threads for the dust cap and then use a bolt that matches the tube cap to pull it. That should create enough force without damage.

Thanks for the heads up everybody :)
 
JeffM

JeffM

Active Member
I don't know your bike or what you have done to it, but some one went to a lot of trouble to caculate the "trail and rake" so your ride would not fall over (flop) or go straight on into traffic.
When you do the calc's you have a small window to play with.
Example: on my K9 it has 12" overs and 3 deg rake as std, so i could ride it up my driveway without bottoming out i put a 0 deg set of trees on and that raised the frame 3/4" and did not affect handling.
So you can play a little bit. I had a Honda 750 4 i put an 8' springer front end on (1976) looked very cool BUT once you got to a corner you had to almost stop and put your feet down...... very scary.
 
JoeHawkins

JoeHawkins

Member
Interesting info! Thanks everybody.
I did take one more go at mine and the just wont come apart so it's of to fleabay to get new ones, in the same length.
 
FrankBDPS

FrankBDPS

Well-Known Member
Did you try bigdogpartsking. They may have something for your bike. Smart move to keep it stock.
 
JoeHawkins

JoeHawkins

Member
@FrankBDPS no, stupid me was in such panic that I ordered a pair from fleabay without checking our local store "Cycle Boyz" and now I gotta wait 3 weeks to get them instead of 3 days from them. That'll learn me , doh!
 
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