Diving under heavy braking

[cakeman]

Hi (and thanks in advance for your help!), Ive only had me s4r a couple of months now and am riding a bit more spirited. Under heavy braking before turn in, the front seems to dive quite aggresively.

I know NOTHING what so ever about suspension and am wondering if anyone could shed some light or suggest anyone to see in the sydney area. A bit firmer under heavy braking is essentially what im looking for without compromising normal riding to much.

Thanks!  

[stopintime]

You have your new gold wheels and now you want good suspension as well? 

If you're larger than the 65kg Italian Ducati kid test rider, you're probably going to have it adjusted for your weight and riding style. That's a (small) piece of cake for a shop to do. Less than an hour. If you're far from the Ducati kid, as I am, you might need to get new parts as well for the suspension to perform well.

Welcome to the Accessories & mods

[cakeman]

well, im about 10 runs short of a ton
Maybe the shop might be able to help but with a 50% weight increase over the Ducati Kid, im assuming ill need some HEAVY duty parts!

Im going to book in a service and tune at gowies (when my mid pipe arrives), would they do suspension as well?

A

[Dannog]

You probably should check out your whole suspension setup first to make sure that everything is correct for you. I've copies this from the DucShop performance center:



SUSPENSION SET-UP

To check the front and rear suspension sag on your bike you will need bike stands front and rear. This will allow your suspension to hang down in an unloaded position i.e. the front stand should mount into the bottom of the steering stem or frame and the rear stand should mount onto the foot pegs or the frame somewhere (not the swing-arm) so that the wheels are off the ground. If you do not have these types of stands then a couple of strong friends will be suffice.

Front forks
1.   Set the bike up on the stand or get your friends to lift the front up so the forks are fully extended. Measure from the fork seal to the top of the fork bottom (the piece of chrome tube that fits into the upside down fork) or from the fork seal to the bottom of the fork triple clamp (conventional forks). This is measurement L1, write this down.
2.   Sit on the bike in your normal riding position. If you ride in leathers then it is a good idea to have these on to get the correct weight. Push down on the forks then let them settle. Measure the distance using the same points as above and write this down as L2.
3.   Lift up on the forks until they are completely extended and let them settle (do not push on them) and measure again using the same points; this is L3.
4.   To calculate our actual spring sag we need to take average of L2 and L3 (L2+L3 div by 2 = average) then L1 – average equals our spring sag. On a street bike it should be about 25-35mm (approx 1/3 of the total stroke). On a road race bike it should be 25-30 mm. To adjust, you will use the preload adjusters on the fork caps, or if you don’t have any, then you need to change the preload tubes inside the forks.
5.   The difference between L2 and L3 can be put down to the amount of friction in the fork seals and fork bushings. The smaller the number, the less friction there is. It should be less than 12mm, if it is more then the forks are in need of some attention. If you have upside down forks then you may want to carefully loosen the bolts on the bottom fork clamps only and go through the above procedure. If you get a smaller difference between L2 and L3, then retighten the bolts using a lower torque setting.

Rear sag
The procedure is basically the same as the front:
1.   Set the bike up on the stand or get your friends to lift the rear up so the wheel is fully extended measure from the axle to a point on the chassis. This measurement is L1.
2.   Have a friend hold the front of the bike and sit on it in your normal riding position. Push down on the rear of the bike then let it settle. Measure the distance using the same point as above, write this down as L2.
3.   Lift up the rear until the suspension is fully extended then let it settle (do not push) and measure again using the same point as L3.
4.   To calculate our actual spring sag we need to take an average of L2 and L3 (L2+L3 divided by 2 = average). L1-average is equal to our spring sag. On a street bike it should be 25-35mm. On a road race bike it should be 20-25,,. To adjust you use the preload adjuster nuts on top of the spring. You will normally need a “C” spanner to do this. The difference between m2 and m3 can be put down to the amount of friction in the linkages and shock bushings. The smaller the number  the less friction there is. It should be less than 3mm. There should also be no “free-play” in the linkages and bushings.

The procedures above are only a guide to setting up your bike and differ from bike to bike and from track to track. By experimenting with different set-ups you will see a difference in how your bike handles. More front sage or less rear sage will make it steer quicker, while less front sag and more rear sag will make it steer slower and not be so nervous over bumps.

[suzyj]

Your S4R forks are already pretty good ones.  They were one of the options when I was fork hunting.  From my research, they come with 0.85 kg/mm springs, which are reasonably firm.  I went for 0.9 kg/mm springs in my 998 forks, and they barely dive at all.

As already mentioned, check and set your sag - it should be around 30-35mm with you on the bike.  If that's okay, then next thing I'd do is check that the oil level is within spec, and then check the compression damping adjusters.

If you want heavier springs, you're welcome to the 1.0 kg/mm ones that my 998 forks came with.  They might be a little on the heavy side though.

[cakeman]

Thanks Suzy,

Getting the required measurements seems easy enough, but as i know nothing about suspension, making the changes might be a bit out of my league

[stopintime]

Thanks Suzy,

Getting the required measurements seems easy enough, but as i know nothing about suspension, making the changes might be a bit out of my league

Measuring yourself will tell you a lot, but where to go from there isn't easy for us who know little.
A good shop will measure for you and tell you in plain language what needs to be done.
The confidence you get from having it professionally done is well worth the money (IMO).

[cakeman]

Is this something Gowies could do or would i need to see a specialised suspension expert?

[suzyj]

I know Mark from desmo clinic is knowledgeable - he got my springs for me.

Try not to drool too much on his collection of bevels tho.

[ecster]

First thing you should do is set the front and rear suspension as per the manual and go from there.

[J5]

Is this something Gowies could do or would i need to see a specialised suspension expert?

i am sure they could arrange something, but should you ?

my thoughts

you take your bike there because they are ducati specialists

but are they suspension specialists ?

a bit like you dont go to a gp for a knee replacement no ?


this is the reciept that i recieved with the monster i bought from Pygmy which AFAIK was a receipt from gowies

this is 3 years ago
shock spring $175
fork seal $35
seal $90
revalve/service forks $225
revalve/service shock $195

+ GST total $720

what did they actaully do ? i dont know

i personally dont like the setup but that could be for a variety of reasons

now for the specialist

www.zenodamper.com.au  , also the guru in rapid mag

I have known zeno for a few years and have seen and experienced his work , he is a suspension guru, he eats , sleeps , thinks suspension , drinks way too much coffee and smokes , and will talk enough to make your brain hurt

has done suspension for many years here and overseas and for race teams all over

thinks a lot outside the square instead of saying ok yeh give me x and i'll give you this and she will be good , is a fan of reusing /rebuilding , mix and match where possible , his desire is for suspension goodness over lining his pocket byselling you  the most expensive product

Stopped by the other day and had a chat and here was 1 option

penske rear shock . new , fully setup, valved , oiled and sprung for riders weight and hose long enough to mount reservoir where you like  $1050 + fit , i had the option of him fitting it and paying or he would allow me to do it there at his shop on a saturday bonus money saved

fork would be on inspection as varying factors of worn parts, work required

penske are a good shock which allows good mix and match of parts , meaning you could use on another bike in the future with some changes of parts rather than having to completely replace the shock and are readily serviceable

a stop by and a chat in lidcombe  are free and gives you some options , he might even give you a coffee  , in fact better to go there for a chat rather than phone as he can be busy sometimes or out

now i just need to find some money for the return visit

[craigo]

I haven't actually met the guy, but there are some awesome write ups from zeno-damper here: http://nswroadandtrackbikes.com/forums/forumdisplay.php?45-Zenodamper

It snapped my brain.

[J5]

I haven't actually met the guy, but there are some awesome write ups from zeno-damper here: http://nswroadandtrackbikes.com/forums/forumdisplay.php?45-Zenodamper

It snapped my brain.

you need to register there , but well worth the read

[mattyvas]

Lots of great info there for you Cakeman.
You are most likely in overload right now, cause I am after just seeing it let alone reading through all of it.

All I'll say is yes you can see Gowie's but there are dedicated suspension places out there.
My bike has had some simple work done to it by Teknik and it changed everything.

They are a little far out being in Penrith area but well worth a trip. 

[Betty]

Cakeman I reckon your base suspension must be better than most. Might I suggest doing a bit of reading (some searching on the forum could be a good start) ... try and get a basic understanding - it will make it easier if and when you talk to someone. If you plan on doing more than setting the preload, it will help to know what preload, compression and rebound mean.

Jim Gunn (Zeno) did the suspension on my bike and I think it has transformed my riding. It may seem unkind but I'd describe him as a little eccentric in a mad scientist kinda way ... but he has a real passion for suspension. He was quite liberal with his information and can dumb it down for simpletons like me.

But J5 is right he doesn't really like the phone but I found him responsive to email ... or if you are close to Lidcombe (apparently Sat is chat day ... don't be early though).