Alright peeps, just sent my b1 reverb off to sram because of it sagging 10mm. Tried the usual bleed and checked the pressure but still sagging.

Has anyone had any recent dealings with sram? I’ve heard they have changed their policy on warranty issues?

Cheers

I think if its in warranty they just replace it now instead of fixing it.

Other way round – they fix rather than replace now.

Got receipt? Ten days or thereabouts…

Thought it was, I know they used to just send you a new one out. My LBS where I brought it from booked it in for me yesterday. Just hoping sram don’t come back and try and charge me for a service cause it’s over 12 months old. Still in the warranty period though.

Mine’s on it’s way to them now.

Evans’s said they’re currently working on a 3 or 4 day turn around, but that doesn’t include postage time.

As for replace or repair “it depends” I was told replace for mine because the stanchion is damaged and it’s unlikely they’ll rebuild the whole thing from parts.

I’m not holding up much hope for mine, they couldn’t understand why it would eat the stanction all off a sudden, but when I removed it from the bike the bottom of it was caked in mud and crap – I reckon it’s full of mud rather than oil and grease – but they said they’ve replaced worse under warranty before.

I’ve already ordered one of the Shimano / Pro posts, so if they’re not keen I’ll have it back as-is and have a play with it myself.

I got a replacement for sag, at the start of the year, made no sense tbh- I could have fixed it in a leisurely hour but it was on warranty so I thought I’d get them to do it.

The replacement’s in for warranty, again, but this time it seems to have fallen into the void

Well, if the general belief is that they are no longer simply replacing all the sagging warranty reverbs, I guess it’s time to start thinking about DIY fix.
I know there are plenty of reverb strip and service videos on the web, but can anyone recommend a “bare-minimum to fix the sag” method?
What’s the minimum tooling required? Syringe and tube to set the fluid height?
Ta

When did you hear of a change OP?

I returned a brand new (old stock) original stealth which was sagging out of the box a month ago, and got a new, boxed B1 in exchange.

My experience over the last few months has been drop the bike off at the shop on Sunday new one on the bike by Thursday. All of mine have been replaced not repaired.

Pretty much. I made my own oil level setting tool out of a syringe and a wee bit of brass tube (it has to be pretty narrow, I forget the number, I couldn’t find a drinking straw thin enough). You could improvise the IFP setting tool as it’s just a tube but it costs £4 so I just bought it. Oh and I bought a crow’s foot for the internal nut purely because the nut was a wee bit damaged on mine- it’s soft and low profile.

Oh and you need a wee bit of improvisational thinking for clamping etc, I did it all with some cheap magnetic soft-jaws but I can’t remember exactly what I ended up doing, there were some workarounds. Not brainsurgery but it wasn’t quite just following instructions either

My LBS said they had changed the policy a few months back, if it’s over 6 months or so old and if it’s mud and crud that’s causing the issue they will service them not replace them.

How hard is the service on them? I do lower legs on my pikes and just done a seal change on my monarch plus. Don’t fancy paying nearly £100 on a service if it’s easy enough to myself

I used this video to rebuild/service my Reverb A1 at the beginning of April this year. I managed without the ‘Service tools’ by improvising but I have since been and bought them – except for the IFP Tool which I made from a bit of Aluminium tube I had lying around….

[video]https://youtu.be/V_Eiv1QaRc8[/video]

Cheers Northwind & JAG. Will probably have a go next time, as mine are approaching end of warranty.

nickdubber – Member

My LBS said they had changed the policy a few months back, if it’s over 6 months or so old and if it’s mud and crud that’s causing the issue they will service them not replace them.

The sag issue’s never mud and crud mind, it’s the IFP seal. TBH reverbs actually seem well sealed, mine were both absolutely mint, no mud bother and tehy get used in some horrible conditions. It’s mostly that the internals aren’t quite right

Northwind; I completely agree; the internals of mine were/are spotless. It seems very well selaed.

sag issue’s never mud and crud… it’s the IFP seal

You’re absolutely right and the Full Service kit includes a new design IFP – so a full Service cures the problem and renews all the seals as well.

From Rockshox perspective (and the Customers) it’s a win/win 😀

My LBS said they had changed the policy a few months back, if it’s over 6 months or so old and if it’s mud and crud that’s causing the issue they will service them not replace them.

Was the suggestion that the customer would be charged for the service?

It’s the new style b1, pretty disappointing because the sag issue was apparently resolved with the new design?

Yes i was told that I would be charged for the service, thats why I’m considering getting the tools needed to service them and doing it myself

The sag issue’s […] the IFP seal

I see this repeated a lot, but have never seen any evidence/justification for the statement.

It is of academic interest mainly, because the sag problem is definitely due to air bypassing one of the internal seals, but logic dictates that it is potentially more likely to be the main piston seal (it has a much greater pressure differential across it, and also is faster moving). The IFP statement seems to originate in a huge thread on MTBR, where it took on ‘de-facto’ status without any apparent evidence.

I wouldn’t hold out much/any hope that the re-designed IFP will cure the problem, but if anyone can enlighten me, I would be most grateful…

JAG – Member

You’re absolutely right and the Full Service kit includes a new design IFP – so a full Service cures the problem and renews all the seals as well.

The new design IFP has the exact same issue unfortunately, it doesn’t cure it.

@Tillydog, Rockshox redesigned the IFP to try and resolve the issue (though weren’t succesful). But also replacing the standard seal with a plain oring seems to prevent the sag developing. Not conclusive but pretty good support I’d say.

nickdubber – Member 
My LBS said they had changed the policy a few months back, if it’s over 6 months or so old and if it’s mud and crud that’s causing the issue they will service them not replace them.

6 months would fit in with the Consumer Rights Act. After 6 months it’s up to you to prove there’s an inherent fault, which is a lot more hassle for people, so easier for them to push that it needs servicing.

Which to be fair it should be pushed on the customer really. A Reverb is really not that much different to a fork, and you’re supposed to service those frequently, not expect a warranty replacement because you haven’t serviced it.

It was nice while it lasted basically, and I think they were doing it just to avoid hassles arguing, but now they’ve said enough is enough as so many are returned now rather than serviced.

[Aside]

Rockshox redesigned the IFP to try and resolve the issue

I don’t know that they ever stated that as their reason for the new IFP. Their motive could also have been cost saving – Old IFP is machined aluminium, 2 seals and 4 backup rings. New one is 1 piece, from SKF(?) moulded plastic.

The old IFP uses standard ‘o-rings’, anyway, does it not (rather than ‘X-rings’)? – albeit with the PTFE backup rings.

[/Aside – sorry]

Rockshox specifically said that the point of the new IFP was to seal “both ways” and keep air and oil where they should be, ie prevent air sucking past the seal.

I’m currently on my third Reverb. The two year warranty runs out next week.

It’s been perfect the whole time but last weekend it went down and stayed down.

Straight into the LBS and sent away to Sram Tech. Apparently they’ve refused to warranty it because of the condition it’s in. Which I’m surprised by, as once I’d removed it and rinsed the mud off, it looked like a brand new Reverb.

I haven’t had a chance to respond yet but I will be. I suppose giving away free Reverbs no questions asked for five or six years has started to dent their bottom line.

Oh, aside- I literally today got told that my replacement reverb was also going to be replaced on warranty, for sucking down. Got a refund, which admittedly I might well spend on another reverb with 2 years more warranty 😳

@sharkattack That sucks, surely it shouldnt be too bad if its the third one in 2 years!

@northwind How long did you have to wait for a reply off them?

Longer than I liked tbh, 2 weeks on the nose. Was only a week last time (and that right before christmas)

Ref; new IFP

There are at least three different designs and each one has been claimed to improve the sag/air/oil mixing issue.

My A1 Reverb currently has the Aluminium IFP, it’s about to receive a home service and be fitted with the middle IFP which is plastic with internal and external o-rings.

The latest and greatest IFP now uses pressure-energised seals to attempt to overcome the relative movement between all the parts inside your Reverb.

I think it’s safe to say that the IFP design is/was the weak link in the Reverb simply because it’s design has evolved more than any other component.

I think it’s safe to say that the IFP design is/was the weak link in the Reverb simply because it’s design has evolved more than any other component.

And yet, the sag problem remains, so maybe not…

Perhaps a discussion for another thread, but I don’t see why the IFP should leak – there’s not really any pressure differential across it: a few PSI, maybe to overcome seal friction. The main piston, on the other hand, can have many hundreds of PSI across it, potentially distorting the seal (oil > air; only ~15PSI air>oil) and always moves faster than the IFP.

As above, I’m only idly curious about whether there is hard evidence behind the belief that the IFP is at the root problem.

It’s a shame the post wasn’t designed the other way up, so that any air in the oil ended up in the reservoir, rather than the active cylinder.

What I’d would really like to do is find a way of retrofitting an air bleed to the oil side of a reverb.

And yet, the sag problem remains

That just means that the Engineers at Reverb aren’t doing a very good job of fixing the issue. No other part within the Reverb design has changed so radically.

but I don’t see why the IFP should leak – there’s not really any pressure differential across it

I don’t understand this comment – I think the pressure differential across both pistons (the fixed small diameter piston inside the IFP tube and the IFP which operates in between the IFP tube and outer seatpost tube) is the same?

Air pressure (250psi) is present behind both pistons and the hydraulic fluid is on the other side of both pistons. The difference in piston area’s being the key to the air spring behaviour.

I had a Reverb that used to sag after about 12 months of use or so. I’ve done all sorts of things to it including the “proper” bleed process, but eventually I discovered that you could achieve 99% of the job by doing the following:

1. Release pressure, remove valve core (you really don’t want any pressure in it!)
2. Remove saddle, remove circlip from top of post under the saddle
3. Using needle pliers, remove the actuation piston (green bit) from top of the post
4. Pour in a bit of Reverb fluid. The amount is a bit of a black art, but suffice to say it will be somewhere between what you had before and right to the top
5. Replace piston – if you put too much fluid in, you won’t get it in. Remove some and try again.
6. Replace circlip. Bleed actuation circuit. Replace valve core.
7. Repressure and test.
8. Repeat if still sagging.

For the avoidance of confusion, the key here is to fill up the pink bit (cylinder) right to the bottom of the green bit (the piston) without getting any air at the top. I found that with a bit of practice, I could get it all done in 30 mins:

Yes, I know this breaks all of the rules, but it worked remarkably well and is much, much easier than a full strip and rebuild.

Hope this helps for people doing the DIY approach.

daern – what you described is perfect if you just have a little bit of sag and don’t need or want to do any other work.

The process you describe can be made much easier and quicker by using the Rockshox oil height tool…

This is designed to get the level inside the post exactly right so that you can then insert the Poppet Valve as you describe.

This makes no sense to me . If the sagging issue can be cured with a service then why have Rockshox continually replaced rather than serviced Reverbs with this issue ?

This is designed to get the level inside the post exactly right so that you can then insert the Poppet Valve as you describe.

Being honest, I thought the “correct” way, was from the other end, but you may well be right. I’m not sure I’d ever bother with the proper tool as I found I could get mine without any sag without a lot of grief (most of the time, I did it first attempt).

Now, if they did a tool to remind me to release the pressure before removing the circlip, I’d be first in line. And in answer to the inevitable question:

“…a huge bang and a 10 ft high fountain of oil…”

🙂

but I don’t see why the IFP should leak – there’s not really any pressure differential across it

I don’t understand this comment – I think the pressure differential across both pistons (the fixed small diameter piston inside the IFP tube and the IFP which operates in between the IFP tube and outer seatpost tube) is the same?

Air pressure (250psi) is present behind both pistons and the hydraulic fluid is on the other side of both pistons. The difference in piston area’s being the key to the air spring behaviour.[/quote]

The internals are pressurised, but very few seals have to withstand the static air pressure. The only moving seals in the conventional reverb that bear the full air pressure during ‘normal’ use are on the poppet valve and the one around the piston rod that attaches the small piston to the base of the post.

The IFP (internal floating piston) just keeps the oil and air separated in the reservoir (the annular space between the inner and outer tubes). As the name suggests, it is free to float, so it will have equal pressure either side of it (if not the IFP would move). It may have 250PSI on both sides, but the pressure *difference* from one side to the other will be as close to zero as seal friction allows.

The force in the air spring comes from the air pressure acting on the area of the rod attached to the small piston (piston rod). The area of the IFP is only relevant to how much the return force varies due to the volume change caused by the piston rod entering the system.

With the poppet valve open, the air pressure will tend to push the piston rod out (raising the seat). Oil can flow from the oil side of the reservoir (above the IFP) through the open poppet valve and into the volume above the small piston. The IFP moves in response to the difference in oil/air volumes in the reservoir. (The total pressure in the post varies slightly in response to the volume occupied by the piston rod.)

When the post is ‘topped out’ there will be no pressure difference across the small piston (the oil above it will have been at the full air pressure when the poppet valve closed – the same pressure as the air below it) and the air spring force will be borne by the top-out bumper (an o-ring).

With the post partially lowered (and nobody sitting on it), the pressure on the oil side of the main piston is lower than on the air side since the effective area of the piston is reduced on the air side due to the presence of the piston rod. I can’t remember the diameter of the piston rod, but if it were ~9mm, the pressure in the trapped oil would only be about 100 PSI for a 250 PSI air pressure, giving a 150 PSI difference across the small piston with the air being at higher pressure than the oil. There is obviously a risk of air leakage into the oil in this situation (maybe trapping pockets of air in surface irregularities in the bore that the piston seal runs in? maybe just slow leakage?)

It would only take ~8kg of upward force to reduce the oil pressure to zero and give the full 250PSI across the small piston (so don’t lift the bike by the seat with the post dropped).

When a person sits on the seat, their weight is borne by the column of oil* trapped between the small piston and the poppet valve. Since the small piston is only ~12mm diameter, an 80kg person increases the pressure in the trapped oil by ~1000 PSI (~7MPa). This puts the oil side of the small piston at a higher pressure than the air side, so any leakage will be oil->air and fairly harmless. It has no effect on the air pressure or IFP since the poppet valve is closed.

*If there is an air pocket in the space with this trapped oil, it will be compressed to < 10% of its previous volume (100 PSI -> 1100 PSI), hence giving ‘sag’. Unfortunately, any air in the oil will tend to end up in this space, due to the design of the post.

Once air has migrated into the oil, it is trapped there, under pressure. When you de-pressurise the post, this air will expand and displace the IFP until it can go no further. Depending on the amount of sag and the travel of the post, this can leave air/oil under substantial pressure. Removing the poppet valve, or dismantling the post releases this pressure in an uncontrolled manner.

Anyone there…

Hello-oo….

Hmm, getting complicated. Got sag on one of mine and I know the bushing is shot from the play in it. Was just going to replace the collar with the bushing, general clean up and hopefully would be good. Videos for that looked simple. The above stuff is way more complex.

p.s. side question – how do you know what model Reverb it is? I’ve got 4 all bought at different times. Some say about silver/black collar, but then there’s silver/black adjuster on the remote, and I’ve found from experience that swapping a black for a silver (wanted to swap LHS for a RHS going under bars), didn’t work. No amount of bleeding and faffing would get it right. Seen some say there’s a difference between them. But is there a difference in the post itself also? Is that A1 and A2 versions? and there’s B1 etc also? Talking non-Stealth here.

For version identification (should land at the relevant place – 30 seconds in – edit: no it doesn’t – skip to 30s!):

[video]https://www.youtube.com/watch?v=V_Eiv1QaRc8&feature=youtu.be&t=30[/video]

Don’t let my previous diatribe put you off – if you can follow the full service video, you can remove the sag (with a little care during unscrewing the inner seal head). The trickiest part is unscrewing the base of the post from the piston rod (“inner shaft” in the service video), but you need to do that for the basic service, anyway.

Although it’s not best practice, you’d probably get away without replacing any seals.

JAG – Member

The process you describe can be made much easier and quicker by using the Rockshox oil height tool…

Worth noting that only works with some Reverbs- I don’t think it works with any of the current stealths

Worth noting that only works with some Reverbs- I don’t think it works with any of the current stealths

Yes, I didn’t mention that mine was an older externally-routed post. I’ve not tried on a newer stealth post yet, but perhaps they don’t suffer from the air-ingest that the older posts seem to get.

Had word back from Evans, if I’m miffed it’s because I gave it to them Friday and it’s only just arrived at their service centre today – they said it would be back from SRAM about now, anyway – they don’t want to send it to Sramtech, he stopped short of using the word “abuse” but I’m told the seal must be full of grit and dirt because it’s worn the head to the metal.

I can’t disagree with him, other than cleaning it I haven’t touched the thing in 14 months other than to go up and down, my forks of course we’re still spotless inside after a similar amount of time.

Hopefully I’ll have more luck with my new Shimano Pro dropper.

Just a quick update. Just picked my reverb up from the LBS, It’s had a new ISP fitted and a rebuild. Only thing I had to pay was postage!
Cheers for the all advice!