Falco Sachs Blue spring question

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#1 Post by **mangocrazy** » Sun Jun 14, 2009 8:56 pm

I am working on a cunning plan that does not require a set of linkages when converting from the rubbish blue-spring Sachs shock to a yellow spring RSV Sachs or Ohlins shock.

For this I really need to know the free length of the blue spring as fitted to the standard Falco Sachs shock. That is to say - how long is the spring when it's NOT fitted to the shock? I'm guessing it's a 6 inch spring, but I'd like confirmation or denial. I'd really like to know overall length to the nearest mm.

Basically I'm planning on fitting a spring of equivalent rate to the standard blue spring to my RSV Ohlins shock and using the stock Falco linkages. I think it should work and I'm going to give it a go. The main reason for this is that the RSV dogbone (when used with the Ohlins shock) fouls my spiffy new NWS hugger whereas with the standard Sachs shock and Falco linkages there is adequate clearance, Clarence.

And I also think that the higher leverage ratio of the Falco linkage should overcome what I regard as overly-firm compression damping on the Ohlins shock.

I will of course post my findings here...

paganman · #2 Post by **paganman** » Sun Jun 14, 2009 9:44 pm

Hi, I've just ordered an NWS hugger for my falco and was planning on an Ohlins shock and associated linkages swap, didn't cross my mind that it'd foul the hugger. What year RSV R shock and linkages have you got? I wonder if different years dog bones might not cause an issue? Failing that I might re-think my plans and spend a bit more on a new Maxton or Nitron shock.
Be interested on your findings, good luck.

D-Rider · #3 Post by **D-Rider** » Sun Jun 14, 2009 11:42 pm

Before I fitted the Mille swinger, I ran the setup under discussion (MilleR Ohlins with the Mille linkage and the NWS hugger)

It's true, the linkage did brush the hugger, but it was no big deal - it's only on the bit that hangs down below the swinger and really isn't noticeable when fitted to the bike.
It doesn't upset the action of the suspension, it's not a heavy contact and the part of the hugger that rubs can move a bit anyway.

Here's a picture of the effect on the hugger after probably a couple of years of this setup:

Personally, I'd sooner have this happening than try to bodge a quality shock to work. Whether there is a viable set of damping settings when running the shock with this different ratio, is really open to question.

If you want to run an Ohlins shock with Falco linkages, the best option would be the 2000 MilleR Ohlins (used the same linkage as the Falco) or the aftermarket Ohlins designed for the Falco (although this has no ride height adjustment).

#4 Post by **mangocrazy** » Mon Jun 15, 2009 9:27 am

I take your points Andy, and I agree that the linkage/hugger contact will cause absolutely no detriment to the suspension action. My concern is with the repeated flexing of the hugger, although as you say there is a certain amount of free movement in that area.

And I think that 'bodge' is a bit of a strong term to use. Certainly Ohlins set up a shock's valving in tandem with the linkage with which it will be used, and I will be moving away from Ohlins preferred settings on this. But I haven't approached this without giving it due thought and anyone who knows me will tell you I prefer to over-engineer rather than leave things to chance. I also think that what I'm planning has some hidden positives.

I've run Ohlins shocks on a variety of bikes and they are quality pieces of kit. But every single one I've used (and this is the fifth) has had very firm (sometimes ridiculously so) high-speed compression damping. They all seem to come out of the factory set that way. On every occasion I've had to have the shock re-valved (sometimes more than once) to correct this.

What I'm planning to do (use an RSV shock on Falco linkages) will have a number of side effects. These are how I see them:

1. Shock travel will be reduced due to the higher leverage ratio of the Falco linkages. This means I will be using less shock travel than I would be on the RSV linkages, so there is less chance of bottoming out and hitting the bump stops. I regard this as a positive.

2. A higher rate spring will be required than the stock Ohlins/RSV one. Having done some tests on the blue spring Sachs shock, it seems that the spring rate at least is pretty much spot on. The shock is crap, but the spring rate appears pretty much perfect (static sag is around 12mm, which is about right). The reason I asked about the free length of the blue spring is so I can work out exactly how much preload is being applied to the spring to give that static sag value. I can then see if I need to 'fine tune' the spring rate.

3. Compression damping should be softened off when in use on the Falco linkages. As detailed above, I see this as an entirely positive thing as the compression damping on the RSV shock is just too harsh for my sensitive derriere.

4. Rebound damping will be weakened (softened) by using the Falco linkages and to maintain optimum control will need to be stiffened up on the adjuster. I'm not concerned by this, as Ohlins shocks invariably have a great deal of scope for stiffening things up, but not much for softening things. I'm confident that I will be able to find an optimum setting given the range of adjustment available, so again I don't see a problem in that area.

I think that about covers it, unless you can think of something else...

Nooj · #5 Post by **Nooj** » Mon Jun 15, 2009 9:56 am

Basically I'm planning on fitting a spring of equivalent rate to the standard blue spring to my RSV Ohlins shock and using the stock Falco linkages. I think it should work and I'm going to give it a go. The

Have I missed something obvious, why not just fit the blue spring to the Ohlins unit?

#6 Post by **mangocrazy** » Mon Jun 15, 2009 10:20 am

No - you're absolutely right, that would be the obvious answer. But it's easier to leave the blue spring on the Sachs shock (and still have it available as a quick swap out) and get a new colour-matched spring for the Ohlins. They only cost about £30, so it's not a big cost.

And people won't think I've still got the Sachs shock fitted...

HisNibbs · #7 Post by **HisNibbs** » Mon Jun 15, 2009 12:30 pm

Hi,
I have the RSVR ohlins, dogbone and a CF NWS hugger too. For a bout 4 years now and I was not aware there is a fouling problem.

I may have to inspect ..........

#8 Post by **mangocrazy** » Sat Jun 20, 2009 2:31 pm

Well - I've ordered (and received) my new spring. I got it from D Faulkner springs of Colchester and it cost me £40 inc. VAT and carriage for a spring with 6 inch free length, 2.25" i.d. (standard bike shock springs) and a spring rate of 800 lbs/in (same as stock Falco OE).

Here's a pic comparing the wire size of the standard RSV Ohlins spring (540 lbs/in) and the new one:

: Springs_2.JPG (56.06 KiB) Viewed 2166 times

And here's a pic of the shock after the Ohlins spring had been removed and the new spring fitted (by Rob Mawbey of Racing Lines in Derby, as mentioned elsewhere):

: Shock_1.JPG (106.21 KiB) Viewed 2166 times

The only thing that remains now is to fit the shock to the bike and see whether my little experiment has worked or not. Watch this space...

sabestian · #9 Post by **sabestian** » Mon Jun 22, 2009 5:47 pm

Wink wink.

#10 Post by **mangocrazy** » Mon Jun 22, 2009 7:15 pm

Cheers Sab, but I've already got an '03 RSV Ohlins and some '03 RSV linkages, so a white spring Sachs isn't high on my list of potential purchases. If the spring swap on the Ohlins shock works, then I'll be laughing. If it doesn't then I'll re-fit the Ohlins shock with the RSV linkages (and the Ohlins spring) and live with the hugger chafing the dogbone.

But I'm sure that shock will be of interest to someone...

paganman · #11 Post by **paganman** » Thu Jun 25, 2009 8:35 pm

Hi, just bought an Ohlins shock off e-bay from a 2003 RSV-R, and got a lovely shiney NWS hugger for my 40th birthday as well, all waiting to go on. So I'm wondering what is she like now, and would you recomend this mod before I get busy with my spanners?

exupmonkey · #12 Post by **exupmonkey** » Thu Jun 25, 2009 9:07 pm

Bugger...just as everyone else is progressing I am regressing! Blew the seals on my white spring sacks today (must cut back on the pies) and had to refit the blue OE shock just to keep me mobile

. Anyone know of a good refurber that will deal by mail order, unless they are near Glasgow?

#13 Post by **mangocrazy** » Thu Jun 25, 2009 9:27 pm

paganman wrote:Hi, just bought an Ohlins shock off e-bay from a 2003 RSV-R, and got a lovely shiney NWS hugger for my 40th birthday as well, all waiting to go on. So I'm wondering what is she like now, and would you recomend this mod before I get busy with my spanners?

Hi Paganman, I'm planning on refitting the Ohlins with the heavy rate spring and the Falco linkages this coming weekend and road-testing as soon as it's done. So if you can wait until Saturday, I should be able to say whether it works or not.

Does the Ohlins you've just bought have a hydraulic preload adjuster or the normal knurled rings? If it has the knurled rings (most do), then it's probably better, as you can replace the spring yourself without needing to find someone with a shock press (assuming you have a C-spanner, of course). Do you have the RSV linkages, by the way?

Exupmonkey - sorry to hear about your seal blowing. I don't know anyone in Glasgae, but John at Revs Racing in Birmingham and Reactive Suspension in York both come recommended by people on the forum. If you Google either (or both) you should find a phone number. I imagine they'd both do mail order.

exupmonkey · #14 Post by **exupmonkey** » Thu Jun 25, 2009 9:36 pm

Cheers for that mate...googling now!

D-Rider · #15 Post by **D-Rider** » Thu Jun 25, 2009 11:18 pm

Just so happens I was speaking to John at Revs Racing today.
I'll be popping over there on Monday for a suspension setup following his servicing / respringing of my ohlins forks.

When I was there previously he was saying he does a lot of work on the white spring sachs' for the Falco community.
Don't know for sure but looking at the feedback on his website suggests that he'll do stuff by post.
http://www.revsracing.co.uk/index.php

Phone or email John - or if you want me to check anything out when I'm over there, just let me know.