Fox 34 Rhythm Bottoming out

Are you setting the sag correctly?
Wear what you would for a normal ride, including back pack if you use one, and adjust the air pressure to give 20% sag. Ride with that and adjust the pressure up or down until it feels right.
Also check how many, if any volume reducers are fitted to the fork and add or remove to get the response you want.

First thing to check is your shock pump. Are you fully engaging the valve when you screw it on. (ie keep screwing on till its tight) Ive pumped the hose to the correct pressure by mistake a few times.

If you increase the pressure check it feels like the fork is stiffer before you throw yourself off something !

fierygasoline said:

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Will open up the forks tomorrow and have a look at the spacers, hopefully I've got a socket that fits

The fork will either need the same sort of tool as you use to remove your cassette or your centreline discs. Alternatively, it may need a large hex socket. You may even have a hex or double hex socket that fits. But be careful! The top cap is TIGHT and it is only aluminium and the edges of the hex are low. It is very easy to round off the top cap. Make sure it is a good fit.

To ensure success, grind down the end of the socket so that the internal chamfer disappears. This will increase contact between the socket and the top cap. You can buy sockets made for the job but they can vary from a Fox one for £30, to ones from obscure websites that will take some finding for less than £3.

How heavy are you? and how are you measuring %sag? I do not rely on tables provided by manufacturers as I have discovered that they just don't work for me. For fork %sag, I stand in the attack position and measure the sag. For shock %sag, I remain in the seated position and aim for the same % as the fork. That will be a starting position only, I make further adjustments depending upon how the bike feels.

You must be doing some really big drops and/or be a heavy person. But maybe there is something wrong with your fork? Forks have all sorts of valves and separate chambers, all of which can get blocked by too much grease, or grease that has gone hard and blocked a channel or valve. It could be worth spending some time on the internet to see if you recognise similar problems and what the cure was.

The only person I have met that rode with 15% sag was a guy on another YT Capra. I had fallen into conversation with him as he had the same bike as me. When I expressed surprise at his need for 15% sag, he told me that was what he needed because he was such a hard rider and that it was necessary to stop the fork from bottoming out. I asked how the bike rode on the trails. He said it was very hard. I asked if he had thought about tuning his suspension's air spring. He had no idea what I was talking about and anyway he had to get on, goodbye! What a shame, he was failing to get the best out of his bike for want of listening for a minute or two. But he was happy, so I bid him a good day's ride, if a hard one!

I don't have a Fox Rhythm 34, nor have I ever owned a 34mm stanchion fork, but I have had a several Pike (35mm stanchion) forks of various travels. I will give you two examples as they may help.

In my full riding kit I weigh 92kg.
#On a Whyte T130, my 130mm travel Pike fork needed 65psi to give me 28% sag. That level of sag was my preference on the 130mm travel fork. There were two tokens in there (maximum was 4) from the start. I never once bottomed out that fork.
#On a YT Capra 160mm travel Pike fork, I needed 60psi to get 30% sag. It came without any tokens. I was getting too much travel on relatively small drops, so I added a token, then one more. Two tokens needed only 50psi to get 30% sag. I later added a third token just to see what the effect was. I needed 45psi to get 30% sag. But this time I wasn't getting enough travel for what I was doing, so I went back to two tokens. With three tokens the resistance of the air spring was ramping up too rapidly and was starting to feel harsh.

I maintain my recommendation to read the guide to suspension set up that I linked to in my first response to you.

Could be faulty forks.
As the bike is new I'd take it back to the dealer and ask them to check out the forks for you.

Perhaps you are experiencing a bit of stiction in the fork seals because of your weight.

Compress your forks while you are in the attack position and let them come back up. Then get someone else (tricky on your own) to move the o ring to where its sat when it comes back up. Measure this as your sag position.