Shocking

My CB900F is in need of new shocks. At least, that's what I take from the
fact that they're both leaking oil everywhere (er...well, one of them
stopped a while ago), and cornering is getting to be more of a thrill than I
ever imagined.

According to bikebandit.com, OEM parts will do me to the tune of around $950
for the pair. I have not even bothered to see if the parts are actually
available, and if that price is nearly right I never will.

From elsewhere (Dennis Kirk), there are aftermarket parts that are said to
fit, for just about $250 for the pair. The problem there is that the shocks
and springs are separate items, and there are two listed spring fitments,
"standard" and "heavy duty". They do list spring rates, 90/130 and 105/150
respectively. But I have absolutely no idea which ones I want. How can I
decide?

 

Indeed. Ikon, Progressive or Hagon would do fine.

A good place to ask for specific recommendations would be the forum at
http://www.cb1100f.net/

You could always buy second hand OEM shocks. Oh look, I've got a pair
here. Mind you, the cost of posting them over the Atlantic is more than
I'd reckon they were worth.

 

What do you weigh?

The typical solo rider weighs about 175~180 pounds and the 90/130
springs are adequate.

It's unlikely that you are an average weight rider that carries a
passenger frequently, so the 90/130 springs would probably work fine
most of the time.

But a rider that's 6' 4" and weighs 240 pounds *might* like the
105/150 springs for solo riding.

Do you know whether the DK springs are true progressives or are
actually dual rate springs? Dual rate springs will provide an
initially soft ride as the closer spaced coils compress, then the ride
will get about 33% harsher *suddenly* as compared to a true
progressive wound spring where the increasing rate continues
gradually.

Also, www.racetech.com has a spring rate calculator program where
riders can enter their weight and their riding ability and it will
deliver the optimum straight wound spring rate for that rider.

 

Crap removed...dual rate/progressive springs are not THE answer.
Usually the single rate does a BETTER job and gives better feedback
across all ranges of performance.

Only decent thing in his post...note he had NOTHING to do with
racetech except to pilfer their knowledge.

 

Get some with the springs installed. Any decent brand will do. Ring the
manufacturers up and give them your weight and whether you are a hoon-monkey
or cruiser type rider and they -should- sort you out.

The softer rate spring is pushing on the harder spring. If you had dual coil
+ spacer type with a silly rate of 50/150 and 1" worth of 'gap' in the soft
spring, by the time that went coil bound, the harder spring would be
compressed by 1/3", or so you'd think. It isn't quite as simple as that, but
that is the barebones of it.

Progressive wounds have the same rate coil, but closer windings at one end.
The number of coils makes a difference. Fewer coils = stiffer spring. It is
just a torsion bar wound in to a spiral after all.