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Okay...I know this has been discussed before---but just posting for a fresh round of opinions.

I have an XC 29er with Fox F29 air forks (3" of travel) and the RP23 rear shock. I've set my sag (and air pressure) to factory-recommended levels for my weight (220lbs)...and I have NEVER once bottomed out.

Am I getting the most out of my suspension? I've heard it said that if you never bottom out, you aren't using your suspension to its maximum capability.

Is this true?

Keep in mind that I've never bottomed out after 2+ years of riding this bike in all kinds of conditions...so I'll probably never take any bigger hits than anything I've done in the past 2 years. (I'm getting older---and looking for all the "cushiness" I can get on rocky trails.)

I know there's nothing stopping me from lowering air pressure---I'm just wondering what the prevailing opinion is on the question of whether or not you should bottom out at least once in a while?

Thanks,
Scott
 

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I wind up bottoming out my fork and rear shock (both air) just about every ride :lol: My rear shock is starting to leak, dont know if its related or not. I bought the extended warranty through my bike shop though so I'm not worried about breaking stuff. I have 2 more years of anything being replaced for free.
 

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Should they bottom out or will they bottom is the question. If your suspension bottoms out constantly you may not have enough travel for what you're doing or the suspension is set up wrong. An XC hardtail with an 80mm fork isn't designed for hardcore DH which is why most DH bikes have lots a travel. Of course even if set up for the style of riding you do there are times when something unexpected happens and you bottom out. If you've never bottomed out your bike there is certainly no harm in running lower air pressures to attempt to get more plushness.
 

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Discussion Starter · #5 ·
what would happen if you bottomed out an air shock? wouldnt it require that the seals blow out??? ive never bottomed out an air fork or shock, but ive bottomed out a coil....
Good question---I have no idea? Is it possible to bottom out an air shock?
 

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I've heard the same thing - if you don't bottom the shock you aren't getting the most out of your suspension -, so when I got my Spearfish I started to play around with the air pressure. IMHO it's a load of BS. I started letting out a little air every ride trying to get there and when I finally did the bike felt sloppy and didn't climb well at all, especially when out of the saddle. I don't hit drops of more than a foot and a half if I can help it, so that may have something to do with it? After my average ride my o-ring looks to be at about 90% of full travel. I have read that getting your shock and fork tuned by a company like PUSH can help get more usable travel without sacrificing pedal performance? It might also depend on your bikes linkage design, my single pivot may be a ton different than a CVA, Brain equiped or DW link, but for my bike, trail type, and riding style I'll be keeping things at the recommended sag.
 

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Okay...I know this has been discussed before---but just posting for a fresh round of opinions.

I have an XC 29er with Fox F29 air forks (3" of travel) and the RP23 rear shock. I've set my sag (and air pressure) to factory-recommended levels for my weight (220lbs)...and I have NEVER once bottomed out.

Am I getting the most out of my suspension? I've heard it said that if you never bottom out, you aren't using your suspension to its maximum capability.

Is this true?

Keep in mind that I've never bottomed out after 2+ years of riding this bike in all kinds of conditions...so I'll probably never take any bigger hits than anything I've done in the past 2 years. (I'm getting older---and looking for all the "cushiness" I can get on rocky trails.)

I know there's nothing stopping me from lowering air pressure---I'm just wondering what the prevailing opinion is on the question of whether or not you should bottom out at least once in a while?

Thanks,
Scott
Bottom out on a spring is easy to understand the spring becomes a solid mass from top to bottom, when each coil touchs the adjacent coil.....this occurs at some finite weight.

An air shock never really bottoms out the air pressure increases until the seals blow....

So obviously you don't want to blow out the seals....

I just run a travel indicator on 90 mm travel fork it I will normally move the travel indicator to within oh 20 mm of the bottom out point (ie no air in the fork)....

The sag tends to be about 20 % normally...

I can never compress the fork even close to where the travel indicator is.....just shows you how hard the hits really are.
 

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Bottom out on a spring is easy to understand the spring becomes a solid mass from top to bottom, when each coil touchs the adjacent coil.....this occurs at some finite weight.

An air shock never really bottoms out the air pressure increases until the seals blow....

So obviously you don't want to blow out the seals....

I just run a travel indicator on 90 mm travel fork it I will normally move the travel indicator to within oh 20 mm of the bottom out point (ie no air in the fork)....

The sag tends to be about 20 % normally...

I can never compress the fork even close to where the travel indicator is.....just shows you how hard the hits really are.
I've had the o-ring on my air fork (revelation) at the very end of the stanchion. Not close to the end, but physically as far up as it could go. Till it was touching the crown I guess it is. My rear shock (RP2) has had the o-ring at the very end of the shaft. Its even slipped pass the end a few times. Where I ride at they have a little bit of everything. Smooth XC trails, rough and rocky trails, and a freeride area with drops and jumps. I ride a 2011 Reign so it is fully capable on all these sections, but if I wanted to never bottom out, I'd have to change air pressure all the time, or ride a lot of pressure which would make the bike ride bad in other sections. So I settle for somewhere in the middle which means at least once on every ride I bottom out somewhere.
 

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Bottom out on a spring is easy to understand the spring becomes a solid mass from top to bottom, when each coil touchs the adjacent coil.....this occurs at some finite weight.
Not true... you should never have the coil links touch each other. It is when the large area at one end of the shaft hits the opposite end. For an air shock it is when the shaft internally hits the end of the unit and it will NOT always blow up your shock.
:madman:
 

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Not true... you should never have the coil links touch each other. It is when the large area at one end of the shaft hits the opposite end. For an air shock it is when the shaft internally hits the end of the unit and it will NOT always blow up your shock.
:madman:
Exactly, this is why the steel springs for coil shocks are rated with higher travel than the shock they go on - i.e a shock with 3" of travel will have a steel spring with 3.25".

Ti springs are differnt as they generally have fewer coils, so they will not coil bind (the technical term for the spring fully compressing) within the shocks travel they are meant for.

As others have said above bottoming every once in a while is ok, and using most of your travel is generally where you want to be.
 

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An air shock never really bottoms out the air pressure increases until the seals blow....
Maybe...maybe if you have the shock inflated over the manufacturer's limits. If you take a shock and put 10psi in it and fully compress it you say the seals will blow? No. Shocks are designed to bottom out without damage when run within the design parameters.
 

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Bottoming out the fork is a bad idea. When the fork bottoms you're suddenly riding a rigid bike, with a very badly front weighted geometry in a situation where travel was obviously a very desirable. Unless you're near the end of that particular bump, fork bottoming is when endo'ing starts.
 

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Yes, you want to tune your shock/fork such that the biggest hits you encounter will almost, but not quite, bottom it out. You want to make the most use of the travel you have, but if you bottom out, your suspension has effectively failed to do it's job.
 

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On the rear of my bike is a Fox Float Air. It uses all it's travel routinely. The only time I've got a harsh metal on metal type of sound from an absolute bottom out was when I was doing DH runs on my XC bike.

My old Marzocchi fork was the same way. Used all it's travel frequently, but if I went beyond it's intended limits, it would make a harsh noise on ultimate bottom out. With proper inflation, that happened less than 10 times, and I used the fork for 5+ years.

My new Rock Shox Reba, also uses all of it's travel. But, I've never got that harsh smacking sound out of it.

Sometimes that harsh smacking bottom out can be a sign of low oil volumes, or under-inflation / too soft of a spring.
 

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Bottom out on a spring is easy to understand the spring becomes a solid mass from top to bottom, when each coil touchs the adjacent coil.....this occurs at some finite weight.

An air shock never really bottoms out the air pressure increases until the seals blow....
As others have pointed out...

False. A coil sprung shock / fork will reach the end of its stroke before the coils come into contact with each other. Case in point, look at Ti springs. The coils are wound much further apart than a steel spring. This does not give the shock more travel. The shaft will bottom out in its housing before the coil runs into itself.

With air shocks, again, false. The air shock hits its physical bottom out limit before the air volume decreases to zero.

What you are saying is somewhat true (a spring - air or coil - can only be compressed so far), but not really relevant when you look at how suspension products are designed.
 
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