Lowering forks on a bike that may see gravel.

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PHeller

Erie, PA
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I love the occasional back country romp. I'm thinking of going in the direction of an ADV XS650, but it will primarily be used for around-town commuting.

I'd like a quicker steering response, so I've considered lowering the forks.

However, I'm worried that lowering the forks will put them in danger of bottoming out.

Can I get progressive springs that would allow for 2 or 3" drop, still soft at the beginning of travel, but stiffens up really quick?

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^ This is what I did. I slid mine up through the trees 13/16ths and use PJ1 30wt. Some may say that is too far up but with the 30wt i don't bottom out. And I got a chance to find out for sure today when someone pulled out in front of me on the highway. When I had 10wt in the forks it would bottom out. I've also got 13 3/16ths shocks on back.
Of course you could always buy a lowering kit from Hugh. Which is what I will do this winter.
 
I might suggest going a small amount at a time.
On an otherwise stock bike lowering the forks by moving them up in the trees will quicken the turning responce. Going to far can make the bike to quick, it can become twitchy. Unstable at speed on a straight line.
Go a 1/4 inch and try it. ride it agressively. Try another 1/4 inch try it. You may find it gets better then suddenly gets worse. At this point go back one step.
Once you find the sweet spot it will handle the best. Even on the gravel it will feel good.
Getting a good 13-13.5 inch shock on the rear to lift the back will help quicken the steering responce.
I might suggest you google motorcycle suspension adjustments. You will learn lots about how to properly set up your suspension.
Leo
 
I understand geometry just fine coming from the bicycling world, I understand that raising the rear will quicken the steering as well.

I'm looking for an aesthetic advantage here as well...I like lowered forks on these old bike...stock they just had that well...70's look.

I don't plan to slide them up in the triples, as I think that's kinda cheesy.

I will try the 30wt to start with though.

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You might want to try sliding the forks up in the trees 1/4" at a time as Leo suggested as a means of testing, then when you've found the angle you like best you could do more permanent and less cheesy changes.
 
brilliant!

I actually need to get fork oil in their first...as I think mine are dry.

Can you still do the damper drilling with 30wt and if so, does it negate the heavier weight oil, or allow for a more response, yet less likely to bottom out fork?

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The oil weight won't stop bottoming out. The weight of oil effects the raste the forks extend an contract. The size of the holes in the damper rod control the rate the oil flows through them.
Thin oil flows faster, thick slower. Holes, bigger is faster smaller is slower.
The strength of the springs controls sag and bottoming out.
To check for oil, pull out the screws on the botom outside of the forks, just above the axle. Some oil my ooze out. Press down on the handle bars and the oil squirts out. repeat as nessasary to remove the old oil. If it is black, it is old.
Put the drain screws back in. Now loosen the upper tree clamp bolts, remove the frork caps. They are under pressure from the springs. Pull out the springs. Pour in about a cup of kerosene or deisel fuel. Put the caps back on. now pump the forks up and downa few times. Drain out the kero or deisel. It will be black too. Repeat untill the kero/deisel comes out clean.
Put in some about a cup of oil, pump, drain. This flushes out most of the kero/deisel.
Now with the frorks compressed springs out fill to 6 inches down from the top with the oil of your choise. Pump the forks a few times to bleed out any air. Recheck oil height.
You can put in 7.5 ounces of oil in each fork, that will give you vey close to 6 inches down.
Put in the springs and caps.
Test ride. If the forks feel stiff try lighter oil. If soft heavier oil.
Leo
 
PHeller said:
I love the occasional back country romp. I'm thinking of going in the direction of an ADV XS650, but it will primarily be used for around-town commuting.

I'd like a quicker steering response, so I've considered lowering the forks.

However, I'm worried that lowering the forks will put them in danger of bottoming out.

Can I get progressive springs that would allow for 2 or 3" drop, still soft at the beginning of travel, but stiffens up really quick?

Posted via Mobile
Click to expand...


Hugh sells what you need to lower your forks. I think he has kits in 2 and 3 inch sizes.
 
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