Suspension question

[Pumba]

Ok I am posting this in here to try and avoid the commets that I will open myself up to in the main suspension forum because basicly I am trying to do this on the cheap.

Following from my race report from that last meeting a comment was made about the front end dive on my bike (somthing I knew about, trust me) and I discovered that Budda had replaced the sprins in his GSXR front end with his old FXR springs.

So I thought I would do a comparison with what I had in the shed.

The top springs and spacers are the GSXR ones, next are a set of RG150 springs and spaces, and at the bottom the set out of the FXR forks.

Now I was kinda suprised by the difference between all these (one of the reasons for sharing) and I was thinking I would try the RG springs given they are simular lengths. The only thing that does conern me is that the GSXR for tubes are a large diameter than the RG (RG springs 27mm dia, GSXR springs 30mm dia).

Should I be concered? or am I worrying bout nothing? and this is a brilient idea that I should push foward with.

All abuse and comment welcomed:done:

[Mrs Busa Pete]

Ok I am posting this in here to try and avoid the commets that I will open myself up to in the main suspension forum because basicly I am trying to do this on the cheap.

Following from my race report from that last meeting a comment was made about the front end dive on my bike (somthing I knew about, trust me) and I discovered that Budda had replaced the sprins in his GSXR front end with his old FXR springs.

So I thought I would do a comparison with what I had in the shed.

The top springs and spacers are the GSXR ones, next are a set of RG150 springs and spaces, and at the bottom the set out of the FXR forks.

Now I was kinda suprised by the difference between all these (one of the reasons for sharing) and I was thinking I would try the RG springs given they are simular lengths. The only thing that does conern me is that the GSXR for tubes are a large diameter than the RG (RG springs 27mm dia, GSXR springs 30mm dia).

Should I be concered? or am I worrying bout nothing? and this is a brilient idea that I should push foward with.

All abuse and comment welcomed:done:

Wouldn't taking care of the leak help first. Turn them upsidedown they might work better that way.

[Pumba]

:Oi:Wouldnt call so much a leak, more of a slow weep. If you want to see leaks I could put the RG front end back on.

Now that was a leak, left pool of fork oil under the bike at the end of any session.

[speedpro]

Use the springs and spacers to set the sag. Then ideally you would change the oil to whatever weight was needed to get the rebound damping right and then alter the damper rod compression damping holes to get the compression damping right.

You do NOT use springs and spacers to stop dive. If they are too soft the sag will be too much and that will be sorted as a separate issue. Damping controls dive but you need to get the springs and spacers right first.

The springs need to be the correct diameter.

Cartridge emulators are worth their weight in gold - literally(almost) but worth it.

[The Stranger]

following from my race report from that last meeting a comment was made about the front end dive on my bike (somthing i knew about, trust me)...

All abuse welcomed:done:

d i e t ! !

[smoky]

From my little understanding; The apparent size, length or diameter is not the best way of assessing the spring tension!
You need a way of measuring the tension of the different spring rates to make a better decision....... I would think?

[F5 Dave]

I'll take Spe to task here & come from the other side & say that without the right springs you will never sort things with damping. With crude damper rods perhaps it is best to run a little stiffer & try & keep rebound in control rather than make compression too hard. Although it is a compromise.

Do a search on measuring & changing spring rate under the mech forums. Have discussed it before. It isn't too hard to measure or increase rate, but there are caveats.

[Buckets4Me]

The springs need to be the correct diameter.



I think thats the part he neaded to hear :jerry:

[Pumba]

Thanks guys for the advice, confirmed what I was thinking sort of but I know about enough to be dangours so a nudge in the right direction never hurt.

I get the message, dont use the different sized springs.

I will have a look round for changing the spring rate as you say Dave.

[Buddha#81]

My front end was tested in battle yesterday and I'm impressed, very impressed.

Right throw the GSX and RG springs. Draing the old oil and flush the forks (replace the seals if you need) I filled the forks with a 110mm air gap using 15wt fork oil, fitted the springs and made spacers the right length to be flush with the top of the fork tubes, so now I've got slight pre loading when the caps are screwed in. I'm 100kg and they allowed me to ride around the outside of a rusty but very experienced rider on a RS125 framed bucket. If you try another combo and it works let us know......I may have blundered across the answer but I'm sure it could be improved.:2thumbsup

[speedpro]

I'll take Spe to task here
I'm pretty sure we both said the same thing but differently. I said set the sag, you said get the right springs.

[SS90]

I'm pretty sure we both said the same thing but differently. I said set the sag, you said get the right springs.

Yea, quite right. Same Same.

One thing that people forget when they set up suspension (and spring rates) for the first time is their "sag rates", and these are different for not only the type of rider you are (fast/intermediate/slow) but also what type of suspension you have. (particularly the rear, and if it is rising rate or not)

With either the front or the rear, if you add spacers (or, indeed "turn the preload adjusters" to "make it stiffer", you may well find that the suspension "Tops out", in other words, "NO STATIC SAG"

In this situation, the damper never operates in it's full range......

If this is the case, no amount of damping changes will correct your woes.

Only changing the "spring rates" will work.

The first thing that I would recommend doing is determining your current sags (static/dynamic), then ensure you have the correct springs (front and rear)

I am sure there is plenty of information available all over the web (and I am sure even on this site on how to measure this.

You only need a good quality tape measure, a Vivid marker, two friends a
and a flat surface to get the measurements.

If they (the sags) are out of spec, then you must replace your springs with items of the right rates.


Then, use your first practice races at the next meeting to "see how it feels" if you have problems with the dampening rates, bring enough tools with you to alter fork oil weight/air gap.

Only the "sags" (spring rates) can be set up in the Garage....unless you have access to a "suspension Dyno", the rest must be done "on the track"

[Buckets4Me]

so dose he change the gsx springs for rg150 ones or not ????
I'm getting baffled with science again :laugh:

[Buddha#81]

so dose he change the gsx springs for rg150 ones or not ????
I'm getting baffled with science again :laugh:

None of the above........He fits the FXR springs!!!!!

[Buckets4Me]

:shit::doh:

my bad
it was all the science jargon with sag and preload and rebound
the women I know dont have an issue with sag yet
rebound and preload maby but not sag (yet)