Cerbera's Master V2.5 thread

[EUC Custom Power-Pads]

I will have my Master newest batch in few days, so I can say nothing about Master and CST-C186, I can only say, that I ride my MSP HT with the CST-C186 since 2.5 years with 20-22 psi and this is already very low for a 80kg fast and aggressive offroad rider. 

In these 6000 km I already had to fix 5 dents in the rim, small as well as large, but still the first rim. 

Lower then 20psi I can't go, but I would if I could. 😅

[Cerbera]

1 hour ago, EUC Custom Power-Pads said:

I already had to fix 5 dents in the rim

Lordy ! How are you 'fixing' dents ?!

1 hour ago, EUC Custom Power-Pads said:

Lower then 20psi I can't go, but I would if I could.

What is your geared-up riding weight, if you don't mind me asking ?

[Cerbera]

Well I am having ALL the 'fun' with the Master this week...

Earlier was adjusting my red knob on the suspension, and checking the PSI therein (was normal) and all seemed to be going well, but then I got an email I had to deal with so popped her back on charge for an hour's top up, and returned then to do the daily ride... and my suspension had gone completely flat !! You can imagine how delighted I was about that, having only just discovered an almost flat tyre last week...

Worse still, attaching the stock pump (ordinarily one of the newer, good ones) and pumping produced only a pffffff sound, the gauge went right up to the top as I pumped and then quickly dropped to zero again, which would repeat every time I pumped. Oh crap I thought - either my shock has borked or the pump has, neither of which is ideal.

I suspected the valve on the suspension chamber first, and got a small screw driver in there to depress the plunger a few times, and fortunately, I am pleased to say, when next plugged up and pumped its behaviour went back to normal and full suspension was achieved, and held for the whole duration of the following ride.

Anyone got any idea what might have happened there ? Anyway, just making a note of that in case it happens to anyone else, and they don't think to twiddle the valve plunger !

 

[EUC Custom Power-Pads]

On 4/19/2023 at 11:46 PM, Cerbera said:

Lordy ! How are you 'fixing' dents ?!

What is your geared-up riding weight, if you don't mind me asking ?

Riding weight 88-90kg

[Cerbera]

Just now, EUC Custom Power-Pads said:

Riding weight 88-90kg

 

I see ! Thanks for diagram !

[EUCzero]

On 4/13/2023 at 11:00 AM, loofv said:

Agreed! I love the master, although I feel the "extreme" will now make the master obsolete. I'll see about getting me one of them backpack covers

They may be similar, but Extreme is a 16" wheel and the master a 18". And for me 18" feels like the perfect tire size for off roading.

[EUC Custom Power-Pads]

Still waiting for my Master (maybe in a couple of days) and I'm sure that after arriving, they will announce the Extrem 18" (real 20" like Master. If true, it will replace my Master next year. 😅

[EUCzero]

The CSTc186 tire works very well on low pressures. But I would not go any lower that 20psi. Myself I ride at 28 most of the time. Sometimes as high as 33 if playing in stairs and asphalt, but my main off road riding is forrest riding. Not hard rocks like tehy do in Vegas
On snow I go as low as 20 to "float" a bit better on the snow. I am 70kg.

I Actually thing to high pressure will let the tire loose the rim. 45-50PSI is way more than it is designed for, and it will expand. Probably enough for it to slide of the rim as well if handled with to much aggression.

[Cerbera]

I think I have a dodgy schrader valve in my suspension. Went to check it the other day, and it had dropped to from 210 to 160 since last service a few weeks back.

Pumped it back up, but an hour later, it had deflated completely ! Furthermore, connecting the stock pump would not inflate it ! I wonder if this is to do with the fact that I have to actually twist the pump to get the threaded shroud on there, which I worry may be twisting the core as well and loosening it. Is that a possibility ?

Got a flat ended Allen key and pumped the valve a few times to check it was seating properly, which seemed to fix it, in that it then pumped up fine and retained that for a week of rides. However, on checking the pressure again today the same thing happened. I presume this means my valve is going dodgy.

Am I ok getting this removal tool set and replacing the core, or does shock valve require something more / else ?

Edited April 29, 2023 by Cerbera

[Hellkitten]

I’ve not removed a shock valve stem core before, but yea that’s the tool and stems that work in tubes! Don’t see why it would be different. 

[Cerbera]

Yeah I was hoping one schrader valve is like any other, but wondered if those cores are up to holding back 250 PSI rather than standard tyre pressures, which of course are a shitload lower...

Edited April 29, 2023 by Cerbera

[Hellkitten]

I did actually change the valves on my v11 suspension. Those are pumped much lower than yours.
They were exactly the same as the tube version. I went to a bike shop and asked if they had any old flat tubes, they had a whole garbage can full. I grabbed a few cut the valves off, I’ve got a few spare now. The valve stem removal tool came with my wheel. Most slime or flat fixing systems come with them as well. 

Edited April 29, 2023 by Hellkitten

[Paradox]

34 minutes ago, Cerbera said:

I have to actually twist the pump to get the threaded shroud on there

This happened to me and when unscrewing the pump I also twisted the pump.  It caused something on the pump to loosen and would not pump air anymore.  I thought it was a bad pump until I twisted the hose and tightened it up and it began pumping again.

[Cerbera]

Just now, Paradox said:

This happened to me and when unscrewing the pump I also twisted the pump.  It caused something on the pump to loosen and would not pump air anymore.  I thought it was a bad pump until I twisted the hose and tightened it up and it began pumping again.

Oh excellent - glad it's not just mine  I will report on how a) tightening the existing one goes, and b) trying a new core when they get here.

[EUCzero]

Why are you twisting the pump?

You must deflate the pressure in the pump before unscrewing it from the valve. Do not unscrew the pump while pressurized. It will ruin the threads of the valve as well as putting stress on the rubber hose.

To pump:

Finger tighten the pump to the shock valve. Important. Do not tighten untill very tight. Should be a little bit loose.

Flip the engage lever on the pump to open the shock valve. Now the pump should not be loose on the shock valve anymore.

PUMP....

Flip the lever back to isolate the pump from the shock

De-pressure the pump by pressing the small deflation button. 

Unscrew the pump from the shock valve.

Easy peasy....

 

Made a video to show it even better: https://www.instagram.com/reel/CrqsnQrAWvR/?igshid=YmMyMTA2M2Y=
 

 

Edited April 30, 2023 by EUCzero

[mrelwood]

On 4/30/2023 at 6:57 PM, EUCzero said:

You must deflate the pressure in the pump before unscrewing it from the valve. Do not unscrew the pump while pressurized. It will ruin the threads of the valve

Exactly! I think I had gone through two shock pumps already before I realized this. And this is why shock pumps without a 2-step valve connector mechanism are worth nothing.

 

 Then about the tire pressures from last page:

On 4/19/2023 at 10:01 PM, Cerbera said:

I have checked the general tyre pressure just with a quick squeeze

Even the e-bike tires that earlier EUCs used remain too stiff to compress much when the pressure drops. Flexible bicycle tires are a whole different matter.

On 4/19/2023 at 10:01 PM, Cerbera said:

what is the lowest pressure I can reasonably put in that tyre

I wouldn’t go below 20 psi for any rider, of any weight. But not because of a risk of damaging the rim.

 The pressure is what resists the tire from rotating against the rim. An empty tire (without a tube) can be rotated on the rim with barely any resistance, and 30 psi won’t slip no matter what you do with it. But 15 psi has a good risk of slipping. And the thing is, the lighter you are the easier the tire slips!

If the tire slips, it grabs onto the tube very well, which rips the valve stem from the tube causing an instant flat with no possibility to steer or balance. A pretty certain crash.

 If you never accelerate or brake fast, the tire doesn’t suddenly slip from its original position to rip out the valve, but it does creep, resulting in ripping out the valve stem down the line anyway.

On 4/19/2023 at 10:01 PM, Cerbera said:

read about people riding their Masters as low as 10 PSI

I really hope they glue the tire onto the rim. Motorcycle tires are (always/sometimes, don’t know which) glued to the rim because they use low pressures and large amounts of torque both accelerating and braking.

[Cerbera]

Hmmm. Still got problems with mine, even after replacing valve core. I am losing a lot of the air in it by 4 hours after the inflation.

I think I am doing the pump thing properly, but if I do what @EUCzero suggested and just lightly screw it on and flip the lever that does not enable air input. I have to have that hose tightened quite a lot before the air starts going in, and holds there. Thereafter I have been OK, releasing air from pump and unscrewing, though again, it does take a few turns of the actual hose and pump itself before it becomes loose enough to do just the shroud. However I am able to check how tight the valve core is with my removal tool, and I put it in firmly hand tight before - perhaps that is not enough and I need to really get that in there hard ?

Holding my ear and various bits of toilet paper up to the valve I can't hear anything escaping or see any movement, yet if I check the next day it'll be down from 220 to about 100 again. Where else could it be leaking from do we think ?

Edited May 1, 2023 by Cerbera

[Hellkitten]

Put some soapy water on it. Sorry to hear you’re having trouble. Do you have a second wheel? 

[Punxatawneyjoe]

5 hours ago, Cerbera said:

Still got problems with mine, even after replacing valve core

Did you use a high pressure valve core? Tire ones are only rated for 200 psi. @Hellkitten is right about the soapy water. You should find the leak fast with a few drops of dish soap in water.

[techyiam]

18 minutes ago, Punxatawneyjoe said:

You should find the leak fast with a few drops of dish soap in water.

Or shaving cream.

[Cerbera]

5 hours ago, Punxatawneyjoe said:

Did you use a high pressure valve core? Tire ones are only rated for 200 psi.

I did not ! I asked about that up further in the thread and @Hellkitten said it didn't matter, I thought the kit I bought would be fine !! However when I removed the old valve core it looked absolutely identical to the new one I replaced it with ! I only pump to 200 PSI ish anyway. 

Thanks for the dish soap trick - that's a good idea I will try later today !

[Cerbera]

7 hours ago, Hellkitten said:

Do you have a second wheel? 

Only little MS3 for emergencies, which I guess this isn't particularly, as I am still able to do short and medium length rides without losing too much air along the way. I did have to pump it up half way round a longer ride for the first time the other day though, in a way that I didn't have to the day before, so it might be getting worse !

If I find the leak isn't coming from the valve I presume no other part of it is user serviceable to fix it, and I have to go back to speedy feet and try and source a new shock under warranty, or swap out for a spring one instead ?

Edited May 2, 2023 by Cerbera

[mrelwood]

 

11 hours ago, Cerbera said:

Where else could it be leaking from do we think ?

I haven’t examined the Master shock first hand, but there aren’t many places where air can escape. The place where the shaft enters the main chamber is a common one on some shocks, though it’s at the negative chamber side of the housing. Depending on how the Master stock balances the negative chamber, that could be your leak.

The third one is the main chamber disassembly threads. Fourth could be the damper adjuster, depending on how it’s designed (or if there is any).

32 minutes ago, Cerbera said:

I presume no other part of it is user serviceable to fix it

Sure they are! Manmade = manfixable!

 Some people have installed volume spacers in theirs, so the shock can definitely be opened up. Greasing the seals could be all it needs. Finding the correct size seals for replacing the stock ones can be difficult though, since the seals are sold as sets for each bicycle shock, not based on their size.

 But if you take the shock to a good MTB repair center, I’m sure they can find suitable seals for you if need be. I’d definitely first try to locate the leak with soapy water, then disassemble the shock and grease all seals though.

 

[Cerbera]

Thank you @mrelwood, you are very encouraging !

I have to admit greasing the seals / valve is not something I had considered. I am guessing silicone grease is best for this, which of course I don't have, but I do have some liquimoly marine grease - do you know if that would do instead ? If not I shall order the other stuff.

 

[mrelwood]

4 hours ago, Cerbera said:

liquimoly marine grease - do you know if that would do instead ?

I honestly don’t know, but since Liqui-moly has a low viscosity, I’d imagine it might work well. Not sure if it sticks as well to the seals though. If I didn’t have a better grease on hand and I didn’t want to bother to get me some, I wouldn’t personally hesitate to use Liqui-Moly. You can always clean it all up if you later learn that it will cause a zombie apocalypse within a year.