Bottoming out

[Architects]

I'm running some derisi revalves and when I first got them I had some nasty bottom outs. Bottoms outs that make me wonder how my frame isn't in pieces. Ive sinced upped the compression about a Turn and a half and rebound 1/2 a turn and its a ton better. I talked with santo and he said a little bottoming out is normal. Curious if those indents are normal? What do you guys think?
http://img.photobucket.com/albums/v215/papertigers23/Derisishocks068.jpg
http://img.photobucket.com/albums/v215/papertigers23/Derisishocks067.jpg

[400exrider707]

What kind of riding/racing are you doing? I run MX and run a similar suspension setup (C&D/GT Thunder) The low ride height offered by the ZPS setup means your frame takes more hits, theres not much you can do about it. I run a full chassis skid now to save it. You also should bottom out once in a while, if you never bottom, you aren't using the full travel of your suspension and there fore not using them to their potential.

[Architects]

all MX. Thats what I figured. Ill have to invest in a skid plate

[mx1791]

yea the dents are normal. mines worse (stock shocks on +3s and MX = shattered wrists and frame)

[TRX450RACER174]

I have the GT THUNDER revalve/spring set up for xc and i bottom out at least a few times during my races but like everybody else says invest in a good skid plate, i am running the PRO ARMOR full chassis.

[400exrider707]

Originally posted by TRX450RACER174
i am running the PRO ARMOR full chassis.

same here

[trompen542]

this is not normal, when they say you should bottom out a couple times per lap that means your shocks, not your frame. When your shocks are fully bottomed out you should still have 1 1/2 inches of clearance between the frame and the ground.

[bradley300]

did you set the rear sag and front ride height before you rode?

[400exrider707]

Originally posted by trompen542
this is not normal, when they say you should bottom out a couple times per lap that means your shocks, not your frame. When your shocks are fully bottomed out you should still have 1 1/2 inches of clearance between the frame and the ground.

Yes you are correct in your theory, except that would be measured on a flat level surface. MX tracks are quite far from flat level surfaces, and my frame looks exactly the same, which is why I now run a full chassis skid.

[Architects]

yes. ride height is 7 and 7 3/8's. Im going to invest in a skidplate and ride the hell out of my quad

[RTN]

This is the way I understand it
Disclaimer..........I'm not a suspension expert by no means

The zero preload allows you to raise or lower your ride height without affecting your shock action, i.e. increasing ride height doesn't increase spring stiffness as on a stock shock.

After presenting the ride height question to one of the top pro's mechanic I was told........each rider is different and he recommends raising the ride height up gradually to a point where the quad starts to become unstable (tippy) in turns and then back off just a tad. The front should be a little higher in ride height. I believe he stated 1/4 to 1/2 inch higher.

Correct me if I'm wrong........won't be the first time :p

[400exrider707]

Originally posted by Architects
yes. ride height is 7 and 7 3/8's. Im going to invest in a skidplate and ride the hell out of my quad

That is a little low already, and a skid plate is only going to put it lower to the ground. I would try something like 8 in the front and 73/4 in the rear.

[XXXRACER165]

Originally posted by trompen542
this is not normal, when they say you should bottom out a couple times per lap that means your shocks, not your frame. When your shocks are fully bottomed out you should still have 1 1/2 inches of clearance between the frame and the ground.


Very true, when you bottom your shocks out now and then that just means your using all of your travel. If you bottoming more than about 3 times per lap however, they didn't set up the shocks right. I know Chris from Meiser racing suspension, trust me he knows shocks! He told me that a lighter spring and slower damping would be a semi-cure for this. But if the frame touches the ground when you bottom, I'd say your frame is bent.

[400exrider707]

Originally posted by XXXRACER165
Very true, when you bottom your shocks out now and then that just means your using all of your travel. If you bottoming more than about 3 times per lap however, they didn't set up the shocks right. I know Chris from Meiser racing suspension, trust me he knows shocks! He told me that a lighter spring and slower damping would be a semi-cure for this. But if the frame touches the ground when you bottom, I'd say your frame is bent.

Bent in what way? Bent downward in the front? The exact opposite way all the force is being applied? I would like to hear your explanation on this.:confused:

[Architects]

Frame bent? You lost me?

[Architects]

Originally posted by 400exrider707
That is a little low already, and a skid plate is only going to put it lower to the ground. I would try something like 8 in the front and 73/4 in the rear.


I'll see if I can raise it up a tad.

[bradley300]

first get your rear sag right, it should be between 4 and 5 inches for that quad. i'd start at 5 (softest) and work your way down a quarter inch at a time.

raise the quad up so the rear shock is fully extended and the tires are just about to come off the ground, and measure from the rear of the frame somewhere (i measured from a grab ar bolt) to the axle. then sit on the quad (with all your gear on) and have a freind measure from the axle to that same bolt. the difference between the first and second measurement is your sag.

now the sag is right, so measure where the rear ride height (with you on it) is at the foot peg. measure 22 inches ahead of that meaurement (should be about where an a-arm mount is) and this is where you need to meaure the front ride height (with you on it) and adjust the front ride height to be .25-.5 inches higher in the front than the rear.

then just ride and raise the ride height a quarter inch at a time on both ends and see what works best

[XXXRACER165]

Originally posted by 400exrider707
Bent in what way? Bent downward in the front? The exact opposite way all the force is being applied? I would like to hear your explanation on this.:confused:


What I meant was your shock mounts are bent up. So when your shocks bottom, the a-arms over extend past normal movement range and the frame touches the ground. I'd measure the specs on a new machine and see if there bent. Sorry sometimes when I explain things it doesn't always come out right the first time.

[Architects]

how do you adjust sag? I dont think my a-arms mounts are bent.

[400exrider707]

The frame would break before it bent at that point, its too ridgid there to bend. You would notice cracks and such. It would never get to the point of deflection where the a-arms would over extend that much. Your upper mounts would have to rip off of the frame for it to get that low.

I too would like to understand the proper way of adjusting sag, I never really toyed with the free sag at all, though your measurements of 5" of sag in the rear seems about what I have now.

[bradley300]

you adjust sag by adjusting the preload. less preload is more sag and more preload is less sag. dont worry about free sag, measurments with you on the quad are the only ones that matter

[400exrider707]

Originally posted by bradley300
you adjust sag by adjusting the preload. less preload is more sag and more preload is less sag. dont worry about free sag, measurments with you on the quad are the only ones that matter

OK what doesn't make sense to me is, how do you adjust sag and ride height, wont these two adjustments/measurements counteract each other?

[bradley300]

you are correct, you are adjusting both, but the sag is more important to tune in than the ride height. the ride height will also be good if the sag is correct.

the sag is constant (unless you gain/lose weight) so it is more accurate to tune the shock its self in, then it is to try and just dial in a general ride height. this is becasue as tires are changed, air pressures adjsuted etc... the ride hieght is constantly changing, so you would be chasing your tail all the time trying to find a non existant "correct" ride height.

the sag controls where the shock sits in its travel in riding conditions, so its more important than getting your quad to sit at a certain level anyway. and like i said, if the sag is right, the ride height will be fine unless your shocks arent valved very well. so dial in the rear sag with you on the quad, then measure your rear rie height just as a reference so you get the correct front height. you dont need to measure the front sag, becasue the front shocks dont work as hard, so if the rear is right, add .25-.5 inches more for the front ona honda (.75 inches for yamaha's) and the front will be right also

[trx250r180]

how much air pressure you run in front tires,i bumped my razr mx 20s up to 14 psi,helped a little with frame scraping,with 7-8 psi my tires were moving about 1 inch more ,push your knee on tire with lower than try with 14 psi to see what i mean,hope this helps