Thread: Bump stop compression?

Thanks John,

No I don't have any charts unfortunately.

The 190 mm was what I had left in travel to reach the bags max rebound length 19.43". (The bags bottom out at 6.78", well before the shock.) This is while the bag was at 12" and my ride height, what I considered standard. (~125 mm bump stop clearance.) Bag pressure 45psi.
The bags design height of 12" - 15", you were pretty spot on with your reckoning.
Your input and advice is greatly appreciated!

My original reckoning was trying to aim at getting closer to in the middle of the bags design height, 13.5". After reading and interpreting those charts and graphs, it would seem my feeble mind was overlooking a whole set of other variables as well.

I'll keep persevering.

Hope I've explained myself a bit better this time too?

OK, I now understand what you meant.

If you set your normal ride height to 13.5" you will find that the pressure of the entrapped air will have risen greatly to compress the air spring fully. Also as the rolling lobe of the bellows is forced out by the bell shape at the bottom of the piston, the effective area increases. This means that the force exerted by the air spring (force = pressure x area) is very high near full compression, much higher than experienced with coil springs, so less likely to hit the bump stop hard.

If you start with a lower ride height the initial volume of air is less, and the difference to the fully compressed volume must be less, so the pressure doesn't increase as much.

Having said that, you are on the right track by allowing for some bump stop compression before your air spring bottoms out.