Two shock pumps blown. Am i doing it wrong ?

I have a new bike with a Monarch Plus rear shock, running with 30% sag but decided to increase to 20% (I am 12 stone. So as i attached my pump and started to increase air pressure from 270 psi upwards the pump gave up on me.
Out to Ribble cycles i go and £30.00 is released for a new one, same process and same result the pump blows at about 275 psi.
Now in order for me to run at 20% sag i think i will be looking at 300 psi.
Question 1 ~ Is that high.
Question 2 ~ Am i just unlucky with the two pumps.
Any help would be appreciated.

300psi? 😯

What bike? That sounds insanely high to me, never heard of anything that high. Never needed more than about 170 in mine and I’m 14st. I thought most pumps only go up to 300 or so so no wonder you are breaking them.

You know what sag means, don’t you? You sit on the bike, and the shock should be 20% of the way through its travel. Surely it’s rock hard with 270psi in it?

Are you sure it’s screwed on all the way and the air is actually getting into the shock, rather than sitting in the little tube? How many pumps does it take to get to 270?

Agree with molgrips, you’re definitely doing it wrong! 300 psi is bonkers high.

My Fox Float was at maybe 140psi (on a 160mm trail bike), and I’m just about 13 stone. That’s at 33% sag (downhills are more fun 😉 )

Not sure why you feel you need to run 20% sag, let alone do it with 300psi. I assume it’s on a short travel xc race whippet?

Giant Reign new one, I called the shop and told them and they said it sounded about right.
They offered that they could add tokens for about £10.00 and charge me about £20.00 for the labour.

If you look at the service manual for the shock it says:

“When pressurising the shock, do not exceed 275psi”

It’s almost like the shock pump is trying to tell you something.

I’m “pretty sure” the Giant reign settings recommend you start with PSI equal to your body weight (in lbs)

so should be somewhere in the 168-170psi range…

I didnt get one with the bike.

https://sram-cdn-pull-zone-gsdesign.netdna-ssl.com/cdn/farfuture/PJfx7QRPuGlFJWU8e9bPKKgflxl8d8nJvsnOWJXXEm4/mtime:1429551315/sites/default/files/techdocs/gen0000000004938_rev_a_2016_monarch_plus_service_manual.pdf

Pg 38

Nice one that makes sense. bit of a long process jobo.

Just legged it downstairs and released pressure ahhhh

Hopefully should get some actual suspension action from it!!

yes when i buy a new pump

Right been and had a go after borrowing a pump. in order to get 40% sag as indicated in shaft i have now got in 191 psi. mmm is it a visit to the shop as i had nevver touched the shock untill last night they set it up after weighing me.

That still doesn’t sound right to me, to get 40% sag the shock needs to move nearly half way through it’s travel with you just sat on it, so that should be quite a bit less than 190psi. I’d have thought.

what sag do you get at 170psi?

edit: how do you measure sag?

rubber ring is past 40% with 191psi i checked that reading with a digital gauge, i have the shock setting on mid setting medium / trail.

Seems strange to me that Ride on felt this was ok.

without wishing to teach you to suck eggs, and forgive me if this sounds rude, but you do know how to set sag?

1. pressurise shock, remove pump.
2. sit on bike in your normal riding gear.
3. carefully get off to see where the indicator has moved to.

Right? (again apologies)

Is it a Debonair? They seem to take a bit more to achieve the same sag. My non-Plus Monarch Debonair takes 260psi to get 25% sag (I’m just over 13st).

No its ok, i am doing that even had my pac on.
I think me and my good steed will be heading over to the shop in the morning.
This is why i came on here to get opinions as when i called them to query it the chap on the phone said all seems fine.
I not happy at parting with 3k and getting that sort of advice.

Yes it is a RockShox Monarch Plus DebonAir RT

yeah shame, it sounds a bit weird, I think you’re right, a visit to to the shop sounds best.

(again sorry for sag thing!!)

http://www.giant-bicycles.com/en-gb/bikes/model/reign.advanced.27.5.1/19231/77352/#specifications

Monarch Plus DebonAir shocks do require alot more pressure to get proper sag. Do a google search and you will see plenty of write ups/reviews etc.

EDIT: See here as well http://singletrackworld.com/forum/topic/monarch-plus-crazy-high-air-pressure

Pretty sure the Debonair is rated to 350psi. Pretty much everything you hear says they take way more pressure than ‘normal’.

Edit: yep, my Monarch Debonair says “Max 350psi” on the can.

its says max 350 on the side if the can

The debonairs do take silly high pressures. I’m only a couple of kilos heavier than you and need 260psi in the one fitted to my stumpy evo. Just remember to add 50psi at a time and compress the shock before adding more. It is a faff but apparently it’s the only way

Release all the air. Pump to 50 and sit on it/press the saddle down a few times. Repeat every 50 psi. Im almost 13 stone and have my rt3 at 165 with two bottomless rings in, so 170-175 without. You shouldn’t be a whole lot more than that even with a plus I would of thought.

Edit… beaten to it.

Debonair can needs higher pressure, will go to 350 so 300psi is high but not ridiculous for the shock, I run mine between 240 & 270. You can’t take what others run in their shocks as any sort of guide, unless same bike same shock. Sounds like the shop advice thus far is good, advice on this thread is mostly rubbish up to the last few. Basically, you’re all good.

Couple of pointers….
Make sure you cycle the bike through the travel periodically while pumping the shock up to make sure the pressure in positive and negative chambers is equalised, this is covered in the shock owners manual.
Check the pressure limit on any shock pump you buy! Most, but not all will go high enough for the high volume shocks such as the Debonair.

Top men tenacious & darrenspink i was beginnung to think i had lost the plot, 50 at a time and lots of bouncing,

How are you measuring the sag ? It may not be as a percentage of the shaft length. Giant manual should tell you. For example, my Anthem should have 8-11mm sag for 30% which is a lot less than a third of the shaft.

I have the same shock on a Canyon Dtrive and i’m running 315 psi so 275 psi isn’t high. Unlucky with the exploding pumps. Make sure you wear glasses. I’d take the pump back. If it says 300psi on the scale it should be able to reach that figure without failing

I have the monarch debonair plus on alibis mojo hd 35% sag 220psi and I am just under 15 stone

30% sag on a Reign is 15.5mm , not 17mm as it would be if the linkage ratio was constant.

Wow there are a lot of people who jumped to the conclusion that something was wrong and offered advice without ever having used or owned the product in question.

It is hard work to get that much pressure in though. RS probably need to supply extra high psi pumps with debonair monarchs.

Hi I’ve just posted something similar about the same shock. I’ve had to put 300 psi in mine to get 25/30 % sag. It say 350 max on the side. Thought I was going to blow the thing up as well as my pump. Hope it’s ok

Also depends on the leverage ratio of the bike as well. High ratio means more pressure.

My spesh Enduro has the auto sag valve. Pump to 275psi and press valve….30% sag. It works spot on. (I then add a few psi as I like to run it a little harder) I’m 13 stone so surprised some are going over 300.mine drops to about 190 with autosag.
It must be to do with different leverage ratios on different frame designs.

.

I’m 13 stone with gear and run 190psi in a debonair air can on a monarch plus. Before I bought the debonair can I was using 170psi.

All depends on the leverage ratio of the frame. The reign is a fair short stroke shock for the travel (57mm stroke, compared to 63mm on my mega for example), which requires more psi to achieve the same sag.

Fwiw I believe the reign has a rather high leverage ratio, combined with Debonair can= high pressures needed.

With the greatest respect to some of the “advice” on the thread, suggesting its high because you run different pressures on different shocks on completely different bikes is really not helpful. I’m running c.70 psi more in my Debonair on my new bike than I was the Fox on my old bike, comparing different bikes and shocks is pointless and only likely to confuse the OP more.