Rear end 'Jump' over speed bumps

[ScarfaceT4R]

Hey there,

I've seen 'clunk' threads over speed bumps - there is no sound besides what you may expect a suspension hop to sound like from a vehicle.

Here's the set-up: rear Toytec 2" Superflex (not HD) coils paired with Bilstein 5160's. Super common, well more so with 5100's, so hoping someone else may be experiencing this & hopefully knows of a fix?

Super annoying because I have to slow to a crawl in order for the rear not to jump when going over a speed bump. This was something I never experienced when I had stock coils on 5100's.

Do I have to just get used to going 1 MPH over speed bumps in order for the rear not to bounce up so much??

:girl:

Hahaa

Thanks!!

 

[Kamil]

Add weight to the back, perhaps three people, see if it still does it, and report back.
I'm thinking those springs are stiff. I've driver 3/4-ton pickups that did that when empty.

 

[ScarfaceT4R]

Add weight to the back, perhaps three people, see if it still does it.

Looks like I'm taking the co-workers to lunch today..

 

[PM_Aero]

Mine is stock and it does it if I'm going 10-15 miles an hour over a speed bump.

 

[ScarfaceT4R]

Mine is stock and it does it if I'm going 10-15 miles an hour over a speed bump.

Interesting... I do't remember that being a thing when it was stock. Prob because I got the 5100's on there a few weeks after I got her

 

[Jetboy]

It's the shocks. Too much compression dampening, not enough rebound for your stiffer springs and lower vehicle weight.

 

[ScarfaceT4R]

It's the shocks. Too much compression dampening, not enough rebound for your stiffer springs and lower vehicle weight.

I guess I should have tested that on some speed bumps during this past weekends camping trip when the back was packed & 3 kids + wife in the rig.

So I'm assuming this will prob lead into the purchase of a new rear bumper/tire carrier - makes for a solid argument when the wife starts complaining about the rear hops.

Good to know

 

[mscot]

LOL

Mine did this all the time with the stock suspension. Bounced the ass to the right on big bumps.
Doesn’t do it anymore.


Sent from my iPhone using Tapatalk

 

[RedSled]

I guess I shouldn't have tested that on some speed bumps during this past weekends camping trip when the back was packed & 3 kids + wife in the rig.

So I'm assuming this will prob lead into the purchase of a new rear bumper/tire carrier - makes for a solid argument when the wife starts complaining about the rear hops.

Good to know

My 2017 SR5 with kings, and 2" OME rear springs did it, but the RSG sliders @ 100 lbs. calmed her down some. :girl: it's not to bad now.

 

[ScarfaceT4R]

My 2017 SR5 with kings, and 2" OME rear springs did it, but the RSG sliders @ 100 lbs. calmed her down some. :girl: it's not to bad now.

I just added some Pelfreybilt slidders on Friday.. Don't know if I've tested on any speed bumps since then, but I'll see if that extra poundage did any calming.

 

[Rightside Up]

I guess I should have tested that on some speed bumps during this past weekends camping trip when the back was packed & 3 kids + wife in the rig.

So I'm assuming this will prob lead into the purchase of a new rear bumper/tire carrier - makes for a solid argument when the wife starts complaining about the rear hops.

Good to know

You Sir are a problem solver.

 

[Jetboy]

If you have really big speed bumps - it might also be just a limitation of suspension travel and you're hitting the bump stops. The rear end has a bit more total travel than the front, but it's mostly down travel. It only has a few inches before you contact the bump stops, so that might play a roll too. The front has a lot more up travel, so it's kinda unbalanced that way. That might be what's kicking the rear end up as well.

But I notice the same thing on mine with Fox shocks. I need to hit them at about 30mph before I can blow through the compression dampening in the rear and get a nice soft ride. At higher speeds it really smooth. But at 15 it's really rough, but only the rear end and tends to kick up like you describe. With some load it settles down pretty nicely though.

 

[ScarfaceT4R]

If you have really big speed bumps - it might also be just a limitation of suspension travel and you're hitting the bump stops. The rear end has a bit more total travel than the front, but it's mostly down travel. It only has a few inches before you contact the bump stops, so that might play a roll too. The front has a lot more up travel, so it's kinda unbalanced that way. That might be what's kicking the rear end up as well.

But I notice the same thing on mine with Fox shocks. I need to hit them at about 30mph before I can blow through the compression dampening in the rear and get a nice soft ride. At higher speeds it really smooth. But at 15 it's really rough, but only the rear end and tends to kick up like you describe. With some load it settles down pretty nicely though.

You know that bump stop theory may be correct. I wouldn't say my speed bumps are larger than any others, but I do have the rear bump stops lowered due to my Toytec 2" rear bump stop drop kit that I installed the same time as my coil/shock pair was installed...If that's the case I would still rather hit those bump stops & have rear jump rather than my wheels rubbing up my rear fenders. Maybe I could switch to the SuperBumps rear bump stops from Wheelers & just remove the Toytec blocks? Looks like those SuperBumps are crazy good at calming the bump.

 

[Jetboy]

At least for my setup, the bump stops inside the coil springs hit a lot sooner on something like a speed bump where the entire axle hits together. I never hit the outer speed bumps on the frame rails except for flex situations. I'm not sure what it would be like with 2" bump stop drops. I kept mine in the stock location and actually cut the first plug off the ones in the coil springs. I don't have any issues with bottoming out but I don't push it all that hard in the whoops ever.

An easy way to tell if that's happening would be to put some type of marker paint on the bump stop and then check if it transfers to the axle tube where it would hit. Any sort of chalk or even a little bit of oil or grease would do the trick just to see if it hits.

 

[wfo9]

At least for my setup, the bump stops inside the coil springs hit a lot sooner on something like a speed bump where the entire axle hits together. I never hit the outer speed bumps on the frame rails except for flex situations. I'm not sure what it would be like with 2" bump stop drops. I kept mine in the stock location and actually cut the first plug off the ones in the coil springs. I don't have any issues with bottoming out but I don't push it all that hard in the whoops ever.

An easy way to tell if that's happening would be to put some type of marker paint on the bump stop and then check if it transfers to the axle tube where it would hit. Any sort of chalk or even a little bit of oil or grease would do the trick just to see if it hits.

You can also place loose fitting zip ties on shock shaft to see how much uptravel is hitting on the shock for the given situation. Push it all the way up then hit the speed bump. How much it drops is how much compression took place. If that is equal to the distance to the bump stop... you are hitting it... Pretty easy to measure when it is all vertical travel like that. Not the same when articulation is at play.

 

[PK930]

Same Toytec springs with Fox 2.0 shocks. Same bounce at lower speeds. Faster seems smoother.

 

[mrblah]

rear wheel hop is normal on body on frame cars and trucks, and it gets worse if you add stiffer springs typically found in aftermarket suspensions. As someone mentioned, a easy fix is to add more weight to the cargo area above your rear wheels, or if your suspension can handle it, drive faster over them (but you may find yourself at the alignment shop more often if you are flying over speedbumps lol).