front springs

[bernardofeio]

Hello
I’m looking for some new front springs to my r100 gs. It have a PD tank but normally is not full.

I’m light (55kgs) and not very tall (1,62m) and I need some off road springs that make the bike comfortable and not high. What do you recommend?

bernardo feio

 

[BegesRus]

Got some progressive springs from 'motorworks' - worthwhile improvement

 

[brassmonkey001]

55kg?
I recommend a sackful of pies, stat!

 

[bernardofeio]

hello

I've been reading some information about r100 springs and I have some questions:

What is "static sag" and "dynamic sag"?

When you measure these distances in front and rear suspension it's the distance from the bike to the floor or the distance measured in the spring/shock?

I did some measurements in my bike (all taken in the spring/shock):

The difference between "no weight" and "bike weight" in front suspension is 30mm. (tank with aprox 15 litres). When I jump in to the bike the front suspension almost doesn't move!


At the rear I have a "hagon" suspension. (it was fit by the previous owner)
With no pre-load in the spring the difference between "no weight" and "bike weight" is 25mm. when I seat in the bike it just travels 10mm. the total travel of the rear shock is aprox 80mm.

I have no experience in motorcycles (I only have 4 500kms experience) but I have lot's of 4x4 experience in all kinds if terrain. I think that the rear suspension is very hard and the front haldo much better, doesn’t seem to handle big irregularities.

what is your opinion? I think I need some upgrade but don't want to spend a fortune...

thanks

"I recommend a sackful of pies, stat"

))))

 

[mikyh]

My thoughts

i'm also short snd relatively light compared to the standard pie munching lot here.

From what you write it seems that on the front you are too hard, and too soft in the back.
If you have total sag of 35mm out of 80 mm shock travel, you need to add a lot of preload, or change the spring. Between 25 and 30 persent is the recomended sag - 20-24mm of total shock travel (assuming you gave the correct travel). What you feel in the back might be too little travel remaining when hitting a bigger bump, and maybe even end of travel.

on your fork however you say you have 30mm, out of 225mm total travel which translate to 13% - much too little - and I guess you have an uprated spring there put by a previous owner.

All this regarding sag and springs only - dont forget you have to sort damping as well - too much rebound makes the suspension feel harsh, too little spongy. compression damping help you handle hits, but too much will also feel harsh.

If i relate my personal experience (I dont know if i have oem or uprated spring in the front) I tried H Milichap concoction once, it was too much damping, but he is a heavy guy. reverted to a little heavier fluid than standard and I'm happy. at the back i have an Ohlins, what can I say - superb.

How do you reach the ground? I'm 1.64 and i have to think ahead at every stop....

Miky

 

[Beemerboff]

What actually works very well is about 50 mm total rider and bike sag at the front, and about 5mm less at the rear.

If you cant get around 45 mm sag at the rear and still have between 15mm and 19 mm preload on the shock spring you have the wrong spring and it should be changed.
At 85 kg I find a Ohlins #80 spring and 15mm preload just about perfect, so you should be looking at a 70 or 75.

Same at the front, you want a min of 15mm preload on the spring, and you usually get this as you screw the top cap on, that is, the spring is just being compressed as the thread catches as you put the cap on.

The stock springs have a long plastic spacer which can be shortened if the springs are too long. I have HPN inserts in the front and the springs in them give about 10 mm more sag than stock.They are a short spring with a long spacer.

Also it is best to drain and refill the forks, the PO might have overfilled or put extra thick oil in - 10 wt works fine on the compression side with the stock springs, but some folks like 12.5 or 15 on the rebound side.

Most aftermarket springs are stiffer than stock, and wont help your problem. So if the fronts are too stiff a visit to a suspension expert is in order- he can whip out the existing and fix you up with something suitable in a flash, and set up the balance , front to rear quickly too.

You wont regret spending a bit to get it right, a well set up GS is a joy too ride and worth a little bit expense.

 

[bernardofeio]

"At 85 kg I find a Ohlins #80 spring and 15mm preload just about perfect, so you should be looking at a 70 or 75."

"#80" is the spring diameter?

I remove all the rear spring preload and adjust the nut at the upper position (so that the bike is as low as possible).When I put the bike in the central stand the spring is completly lose and even have a gap of 10 to 15mm. So probably I might have too little travel remaining and when hitting a bigger bump, and maybe hitting the "end of travel".

Is it possible to buy just springs for the rear suspention?where?

 

[Rob Farmer]

Is it possible to buy just springs for the rear suspention?where?

Hagon - http://www.hagon-shocks.co.uk/main1st.htm I know it's not feasible for you to get to Hagon but they offere a complete setting up service for bikes. You take your bike along and they will set it up for you.

I've got a Hagon on the back of my 100PD, despite the fact that it's starting to fade now it's a surprisingly good shock and I much prefer it to the Wilbers I've recently fitted to my mono g/s.

 

[Beemerboff]

The Ohlins number relates to the spring rate, but exactly what units it is in I cant recall.

Probably n/mm , in which case a #70 is around 400 lb/inch

But anyone who supplies suspension springs will know what their equivalent is.

They should also be able to supply a matching front spring , and suggest preload, fork oil and damper settings to suit their choice of springs

 

[bernardofeio]

What is the standard rear spring length and what is normal total travel of the rear shock?

Does any one have a soft rear spring that is not using so I can test it in my bike?

 

[Beemerboff]

The length of the spring and the total rear suspension travel is irrelevant to your problem , but for what it is worth my 80 n/mm spring is 230 mm long.

Measured at the shock I have 65 mm between the bump stop and the bottom of the shock with no load, approx 10 mm bike sag and 5/6 mm more rider sag.

Given that the wheel travel is a little bit less than three times the shock movement that translates to around 27/28 mm bike sag and 43/44 mm rider sag at the wheel.

It is important that the front has slightly more sag than the rear - that can be easily checked by holding the bike vertical and pushing down on the footrest - the front should drop just a little bit faster than the rear.