Reworking/revalving Ohlins forks and shock

[matt_the_blat]

Various articles in PB recently* have got me wondering about getting your suspension tinkered with by professionals (and I'm really just musing idly here) -

*CBR-600RR and GSX-R600

From what I recall from reading here in the past (on the old .com forum, at any rate), unless you have separate high/low speed damping adustment then the normal compression & rebound damping adjusters only alter low speed damping.

My bike (02 Aprilia RSV-R, 18000 miles) is great, but I can't help but feel that the Ohlins suspenders are really designed for smoothish race tracks rather than the (bumpy) British A & B roads I do most of my riding on. My thinking is that you hit a bump in the road at speed and BAMM!!! too much high speed damping and the suspension can't react quickly enough to track the road, resulting in a harsh ride.

I've set the sag front and rear without having to set the adjusters right at the end of their range so I think the springs (original as far as I know) are right for me. Damping is still set to the road settings in the manual so I accept there is still plenty of tinkering to be done there before I start spending money. The forks were serviced a year ago, but I don't think the shock has ever been done.

I've tried backing the preload off a bit more but it still seems a very harsh ride - although admittedly my FZR400 by comparison is as soggy as a damp sponge!

Bearing in mind I'm just mulling this over for now, if I can't find a happy setting with the adjustment I have, is it likely that getting the forks and shock revalved (you can re-valve shocks too right?) and sprinkled with magic pixie dust (by a grown up professional of course) could improve things for my real-world riding?

RFTR,

Matt

[blow_away]

There was some discussion on the old .com forum re servicing the Ohlins on the RSVR? I think it was either MilleMille or Morepower giving the good word. ISTR that the Ohlins forks on your bike need an annual service, but I can't remember what was said about the shock?

I take it you race/trackday (from your avatar)?

It sounds to me that you would benefit from a trackday with suspension help. For a fee, a company such as 100% Suspension will spend the day with you helping get your bike set up as you like it. If the track settings do not translate well to the road, you can ring the guy and get further help on what mods to make. I have not used the service myself (yet), but friends of mine have benefitted from using them.

http://www.nolimitstrackdays.com/acatalog/Suspension.html

(Other suspension setup companies are out there too!)

[roadracer]

There are in fact a lot of options you can do for the street, I'm sure if the suspension was "serviced" by anyone with their head screwed on they would have put the correct oil for you to obtain a setting each for both road and track respectively. Basically, what I'm saying is that the bike has the settings there and won't need an adult to intervene.

Actually lessening preload WILL give you a harsher ride in the damping circuit. Hence why it didn't fix your problem, obviously.

I'd set your preloads at 25/35Fr and 15/35R. Then you need to lessen damping, especially compression at the front as this will lessen the need for the high speed circuit adjustments(it will let the oil flow easier through the low speed and won't rely on the high speed to allow wheel travel over bumps).

Where are your preload adjusters set with the above sag settings?(2 turns in? 5 turns in? 8 turns in?)

I can help with much nicer damping suggestions after I find out your weight and what the current settings are, hopefully. Damping settings are counted from full in(and turned out) preload is measured from full out (and turned in) until the desired measurement.

[MonkeyJim]

It sounds to me that you would benefit from a trackday with suspension help. For a fee, a company such as 100% Suspension will spend the day with you helping get your bike set up as you like it. If the track settings do not translate well to the road, you can ring the guy and get further help on what mods to make. I have not used the service myself (yet), but friends of mine have benefitted from using them.

http://www.nolimitstrackdays.com/acatalog/Suspension.html

(Other suspension setup companies are out there too!)

Well i can vouch for 100% suspension, Colin set up my bike at Rockingham which was about a week before the PB forum bash at Cadwell.

£45 for an all-day set up. My basic set up wasn't that bad, but it was money well spent & now it's spot on.

Others that get recommended regularly [though not used by me yet] are MCT in Stowmarket and Reactive suspension

[dizzyr1]

I was kindly informed by an ohlins tech to put the high speed damping at the middle setting and leave it alone, i have been through my suspension a thousand times and it has been fun trying loads of different springs, ride heights, seven track days with seven totaly different setups, now mines bob on, but the first thing was to get the shock serviced and went from there.......i rubuilt my forks on regular basis, and the shock gets a major every twelve months.

And you are doing the right thing by asking, but have some fun playing also....and if its only £45 quid to have an experts advice then give it a whirl, could save you a fortune in tyres.... in the long run.

And for rebuilds or advice K-tech K-tech K-tech, have had horror dealings with others, they value custom and reputations.

[millerich]

My experience is that they can be set up for typical British A and B roads. I had Revs suspension service my shock and forks and the shock spring replaced with a heavier spring. Suspension was then set up for my weight and to allow for a pillion and it seems to have worked wonders. Was good before but now even better and seemingly no worse around the 'Ring this year than it was before it had it's "real roads" set up. Changes were just down to the adjusters and the shock spring, no revalving was done.

[2 smokes 4 ever]

Matt

you say you've set the sag but you don't say what you've set it to

I've been going through something similar recently on my SV1000

Std shock and (non std size) spring - way too hard (450lbs/in)

ditched for a

WP shock (for road use) came with same spring rate as Suzuki shock

ditched for a

Elka 3 way shock - came with kidney jarring 500lbs/ins spring despite me say it was for road use.

Have now got a 325ibs/in spring fitted to it

Sag to aim to aim for

Front

Static (Free) Sag (60-70% of Dynamic Sag) 15-20mm

Dynamic (Rider) Sag (25-30% of Full Travel) 30-35mm

Loaded Sag - (Dynamic Sag - Static sag) 10-20mm

Rear

Static (Free) Sag (15-25% of Dynamic Sag) 5 - 10mm

Dynamic (Rider) Sag (25-30% of Full Travel) 30 - 35mm Street

Loaded sag (Rider sag - free sag) 20 - 30mm Street

Rear static sag needs to be nearer 15mm for UK roads - I use the term roads loosely, with a coresponding increase in the Dynamic sag value

I've currently got 13(static) 39 (dynamic) 26mm (loaded) sag figures

Its a tad harsh still but not bad on UK roads and fine for expert group trackdays.

You can't compensate for the wrong spring rates by over or under setting the damping

[matt_the_blat]

Thanks for all that - pretty much the same as loads of other references on the web, but for the record:

Front:

static sag = 26mm

rider sag = 35mm

=> loaded sag = 9mm

Rear:

static sag = 13mm

rider sag = 32mm

=> loaded sag = 19mm

Incidentally, I haven't seen or heard the term loaded sag before

On the old .com forum there was a suggestion from millemille that Ohlins shocks tend to lose their damping when hot (I think that was it) and advised running it with 12-15mm static sag, hence my settings.

But hey, it is but the work of a moment to twiddle the suspenders so I'm open to suggestions and happy to try stuff

Incidentally, part of my motivation for this (bearing in mind the time of year) is that I went for a ride a few weeks ago, which turned into a proper wet one - going down bumpy B-roads in those conditions the back end in particular seemed prone to kicking off the bumps and stepping sideways rather than soaking them up - I may not be a world champion but I can tell the difference between me provoking a bit of a slide with the throttle and when because of something else

Cheers,

Matt

[roadracer]

The springs look pretty good for your bike, but I bet the rear shock oil has gone and the old Ohlins oil actually goes very gummy and sticky, so I you won't get good results until it's serviced. 18,000miles is a shitload of work for a shock, especially if it's six years old oil inside.

The old shock oil won't even be cleaned off with solvent I'd say, dishwashing liquid and warm water are needed when the service happens. It's probably not allowing smooth movements (especially the more subtle increments needed for a smooth comfortable ride) and the gummy old oil will definitely feel harsh with out any of the "stiffness" benefits. Namely, it will just feel crap like you've mentioned.

Have a crack at winding off 4 clicks of compression on the rear shock, and 1/2 turn of rebound to see if it is even still adjustable. If that works, hey presto-job jobbed. should be nice.

I've changed my mind at least, I'd say you're just fingering the shock that is about fucked, not that it has a "bad setting". Get them to use proper Ohlins oil in the service when it happens, too. The only other decent replacement is Silkolene, but that will nullify the "stock" settings as it is a slightly different viscosity for a given temperature.

[2 smokes 4 ever]

Thanks for all that - pretty much the same as loads of other references on the web, but for the record:

Front:

static sag = 26mm

rider sag = 35mm

=> loaded sag = 9mm

Rear:

static sag = 13mm

rider sag = 32mm

=> loaded sag = 19mm

Incidentally, I haven't seen or heard the term loaded sag before

On the old .com forum there was a suggestion from millemille that Ohlins shocks tend to lose their damping when hot (I think that was it) and advised running it with 12-15mm static sag, hence my settings.

But hey, it is but the work of a moment to twiddle the suspenders so I'm open to suggestions and happy to try stuff

Incidentally, part of my motivation for this (bearing in mind the time of year) is that I went for a ride a few weeks ago, which turned into a proper wet one - going down bumpy B-roads in those conditions the back end in particular seemed prone to kicking off the bumps and stepping sideways rather than soaking them up - I may not be a world champion but I can tell the difference between me provoking a bit of a slide with the throttle and when because of something else

Cheers,

Matt

I kinda made the term loaded sag up, as I couldn't find a techincal term for it but you seem to have grasped the idea

From my perssonel messing, 19mm of loaded sag on the rear is too little (spring too stiff) for UK roads

You need to go down on the spring rate by at leaset 50lbs/in

I'm not surprsied to felt bad in the wet either

My SV feels way too stiff with 26mm of loaded sag, in the wet

Good place for springs is Demon Tweaks, who sell Faulkners Springs for jus tover £20 ea.

A littel cheaper than most places who seem to think they can charge £65 for a fucking spring

The front seems too stiff as well

Softer springs with more preload is the way I'd go.

PDQ in Berks sell Race Tech springs with a good range

RaceTech website has a good on line tool to suggest your correct spring rate based upon your weight and riding style

Give it a go at RaceTech.com

[matt_the_blat]

If it's not too personal a question, how much do you weigh?

No, not at all - I'm 68kg in the nip so I guess you need to add, what, 5kg to account for riding gear.

Roadracer - thanks for the tips. I think the first step is definitely to get the shock serviced.

2 smokes - I know PDQ well as they're not far from me. That's where I go for my Aprilia spares and they serviced the forks for me a year ago so that's where I'll be taking the shock. Actually, strictly speaking the forks are probably due for yet another service already! Poxy bloody Ohlins mumble grumble jibber moan.....

(I should point out that I'm currently servicing the bike and trying to persuade the bastard oil filter cover to stop weeping!)

[matt_the_blat]

If you've got the oem springs in there then they will be cock on for your weight.

The forks and shock shouldn't need revalving either - I used mine on standard valving for everything from sunday morning blasts to 55s laps of Brands Indy with nae bother..

You can play with things like oil weight and air gap in the forks fairly easily but the shock is more difficult to do the same to (unless you have access to pressurised nitrogen).

Where is the problem? Front or back?

How can you tell the springs are wrong? (I believe you but more wisdom required ) I thought that if you get static and rider sag both in their "magic" ranges then that's a good indication that the springs are OK?

Not being an expert it's hard to pinpoint where the problem is, but with the forks having been serviced only a year ago I doubt they're the problem. Regardless of that I'd guess it's the shock anyway - like I said, the back end tends to kick off bumps (especially in the wet) rather than absorbing them. And at my last trackday at Silverstone I kept getting a shimmying through the bars as I got on the gas coming onto Hangar Straight - my idiots guide to suspension tells me that's likely to be a problem with the shock (too little rebound damping I think it was).

Wondering aloud for a second, can I safely assume that a knackered/badly set-up shock will increase rear tyre wear?

Incidentally, a recent PB article on tyres hinted that a wear pattern like I have on my rear tyre could also indicate too little rebound damping and could cause a vibration through the bars under braking - remebmer my juddering brakes? (still not sorted!)

Looks like a call to PDQ to get the shock serviced (and re-sprung?) is in order - pronto.

Oh, and I do occasionally have access to pressurised gas but usually only after a vindaloo

[2 smokes 4 ever]

Well with 9mm of loaded sag a the front and 19mm at the rear (Dynamic sag - static sag), I'd say the springs are far too hard for road use

How can free sag reduce when the shock gets hot?

Get the sag right (ie new springs), preferably towards the top end of the figures I posted, then start messing with the damping

[matt_the_blat]

Maybe my venacular has confused you - if your bike is on the standard springs then they will be correct for your weight.

Ah, capiche Had you said cock-on I'd have got your drift (several hours and some Shiraz later, that is indeed exactly what you said )

Cheers for all the tips thus far everyone

[2 smokes 4 ever]

Bike suspension set up 101 - on an unladen bike the front suspension carries the greater proportion of the bikes weight, stick a rider on it and the rear suspension carries a greater proportion of the rider weight.

No - most bikes are 50/50 unladen, Trailies and dual purpose bikes are rear heavy when unladen

Front sag on a road bike should be ~25mm unladen and should sag a further ~10mm when the rider is on board in the riding position.

Sorry but these figures work well

Static (Free) Sag (60-70% of Dynamic Sag) 15-20mm

Dynamic (Rider) Sag (25-30% of Full Travel) 30-35mm

Loaded Sag - (Dynamic Sag - Static sag) 10-20mm

Production Ohlins shocks - the oem kit not the aftermarket - looses free sag when they get very hot (which they do on the Aprilia due to the proximity to the exhaust), I'v never been able to get a straight answer from any one related to Ohlins as to why (if you can even get them to admit it - particularly as it production kit which the aftermarket distributors get very sniffy about). One of the guys in the states who has raced Aprilia's at AMA level did offer an explanation over on apriliaforum.com some years ago but I can't remember what it was exactly - something to do with the oil displacement circuit gettting pressurised and pushing down on the piston AFAICR

Yes the nitrogen pressure will go up when it gets hot, but in comparasion to the spring force its bugger all, esp as its only acting on the CSA of the rod

Oil circuit is already pressured to stop cavitation

My SV1000 is the same, the shock sits next to the rear exhaust header and gets to hot to touch

Sag doesn't alter between hot and cold

[2 smokes 4 ever]

Alway base any readings on fully warm suspension as a matter of course

The sag figures do work!

Suspension is cold for the first 15-20mins of the ride - its when everything is nice and toasty you want the setting to be correct

Wouldn't know 'bout the Ohlins Sag issue - didn't buy one coz they don't fit properly on the SV

Got a luverly red & yellow Canadian Elka - Top quality shock

Only shock you can buy with a check valve to totally prevent rebound adjustments affecting compression & vicky versa

Thrust bearing on top of the spring

Huge range of Hi & lo speed adjustment as std

Very little fade, which considering where it sits (right next to the exhasut header) is amazing

Far far superior to the WP4014 fusion shock I had on it before

[roadracer]

[2 smokes 4 ever]

Elka (not that well known in Europe for road bike stuff, but are well known in the ATV world) actually recommend 25 - 35mm of 'loaded sag' (dynamic sag - static sag) for road riding.

When the shock arrived from JHS in Bristol, it was fitted with a 500lbs spring and they swore blind it was the right one for my weight, despite making the rear feel solid - The loaded sag was 18mm ie rear suspension compressed 18mm we me sitting on bike. fine on a race track, not on UK roads though. Spring rate needed dropping to 325lbs

Yes - too achieve these figures you need a softer spring with more preload

I have 15mm of pre-load on the rear spring (Free length - compressed length as fitted to the shock), and a loaded sag of 26mm

WP recommend 5 - 10mm of static sag

WP importer says 15mm is needed on UK roads

Suspension threads are like oil threads - everyones got an opinion, and believe theirs is the only right one

[roadracer]

Are either of you actually considering that the OP's problems are related to sag or spring issue? If that's the case, then neither of you should be "discussing" shit. The problem is not when it's wet but in fact because the suspension damping is cold in the rain, and needs to be adjusted accordingly with the shock temperature.

It's simple as. Not a fucking tennis match of "look how much I know on the internetz!!".

[2 smokes 4 ever]

Are either of you actually considering that the OP's problems are related to sag or spring issue? If that's the case, then neither of you should be "discussing" shit. The problem is not when it's wet but in fact because the suspension damping is cold in the rain, and needs to be adjusted accordingly with the shock temperature.

It's simple as. Not a fucking tennis match of "look how much I know on the internetz!!".

Nothing like a bit of constructive criticism

And your contribution to this thread is......