Mon Dec 2 12:58:28 1996
- Message No. 234
From: Martin Franz <100265.3434@CompuServe.COM>
Subject: Re: front fork : oil, air or springs.
Hi !
>> If additional air in the front fork is bad, why did Honda put these
>> valves in the fork ??
>> They could save the money by leaving them out.
as far as I know, they removed the ventils from the 96 modell. But I'm not
shure.
>>You could also put other oil in the fork but there is a world of
>> difference betweeen a SAE 10
>> and a SAE 25 oil.
The normal way, is not to fill in a plain grade (SAE 25/SAE10). Fork oil from
the same manufactor can be mixed.
>> The dampening of the fork is the only thing that changes.
This is definitly true. And wanted. Some bikes have knobs for that...
>> And this is
>> even dangerous !!
>> The front wheel has to come back on the road as fast as possible after a
>> knob in the road.
If the front wheel comes back as fast as posible, it will definitly shoot you
off your bike. Thats why damping is for, that it comes back SLOW and without
power. Think of it, when the fork "goes in" cause of a knob, it will go out
later. when its going out fast, its bad.
>> If the dampening is to high, the contact with the road is worse.
>> Think about you driving in a corner and the front wheel looses contact
>> with the road longer
>> than nessesary.........
With harder damping, contact with the road is improved. And, there is much
better feedback from the road. These "feedback" can be anoying (as you feel
every stone), thats the reason, why softer damping feels more comfortable. When
you want to go on the limits, you need the feedback, or you won't survive it
very long. With too soft damping, your bike will start to "swing" in curves,
thats realy bad. There is a lot of dynamic load shifting while breaking or in
hard turns, those shifting should idealy not "move" the fork.
>>> making the bike higher by increasing the pretension of the spring
there is no reason to do so, except you weight more than 150kg or so. And, if
you have that much kilos, harder damping will improve much more. Small example:
breaking, if your weight suddenly shifts to the front, a undamped (or too soft
damped) fork will "go in" heavily; while it "goes in", there is not much weight
n the front wheel, the front wheel will block. You have to wait, until all the
weight is on the whell, before applying "full break". When you then go off the
break, the bike will "jump", cause suddenly the spring will extent. So, they
more weight is on the bike, the harder you need to damp. (okay, a harder spring
will also prevent the bike from "going in", but remember, the dynamic weight
shift on the @ is about a sudden 100kg more on the front...you have to make it
quite stiff, there will nothing left for "normal" conditions)
Making the bike "higher" by adding air is realy not a wise thing to do. First,
the "height" you can add is only some centimeters, otherwise you loose your
"negativ" spring way completly. Second, the spring will "not overlap" much,
causing it to block on heavy breaking (and this happens, belive me, even without
adding air...).
Last, not least, there is added instability.
>>> making the bike higher
The only good way, is to implement longer "standing tubes" (Standrohre), wether
by putting on a completly other fork, or (which I would not recomend too much)
by screwing in an extension at the upper side (which no TUEV on the world will
allow, somebody already mentioned that).
>>> speed bumpers
Offroads, I got over a 1 meter high hill with speed 100km/h. I learned two
things, first, yu can take most hills by virtualy any speed just standing up in
your "fussrasten" and putting all your weight on the rear parts (you are then
not shot over the bike at the landing :-))), second, you should not try to clean
your visor at 100km/h (think, that added some points on my squid test :-)))
A better speed bumper (in vienna) is 30 cm high. Your suspension can take at
most 22 cm. Without damping, bad things will happen...
last words about the damping:
For mixed environment (offroads/onroads) there is IMHO no reason, to change the
damping for the front fork, unless you weight more than the average or you go a
lot with socia/us.
have a nice slide, Martin
P.S.
>>> There will come aluminium particles in the oil.
a very last question: where does the aluminium should come from ? Aren't the
moving parts made of steel ? Maybe I'm wrong.
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