Anybody seen/used this bump stop kit?

I would also recommend just buying an SVC bump kit.

roostinyfz said:

Just genuinely curious how you figure 4” more bump travel out of a spring under? Asking because I’ve thought hard about doing it but haven’t seen this bump travel claim of increased with SU before. SDHQ told me the travel amount is still the same?

Click to expand...

1. there will be more travel by way of the spring needing to be longer to be at the same static ride height as spring over.

2. raptors have plenty of down travel. they really need more bump travel, total travel numbers being equivalent, going spring under moves the axle tube Up and you'll get a bump travel increase that is equivalent to the axle diameter.

If the spring can travel the same distance (but in reality due to the longer spring length, you get more overall travel with spring under) changing the spring mount from over to under adds 4" of up travel and robs 4" of down travel.

the springs will have a greater arch but will be as soft or softer than spring over.

The truck really shouldn't tow or haul a ton of weight once you go spring under for obvious reasons.

zombiekiller said:

1. there will be more travel by way of the spring needing to be longer to be at the same static ride height as spring over.

2. raptors have plenty of down travel. they really need more bump travel, total travel numbers being equivalent, going spring under moves the axle tube Up and you'll get a bump travel increase that is equivalent to the axle diameter.

If the spring can travel the same distance (but in reality due to the longer spring length, you get more overall travel with spring under) changing the spring mount from over to under adds 4" of up travel and robs 4" of down travel.

the springs will have a greater arch but will be as soft or softer than spring over.

The truck really shouldn't tow or haul a ton of weight once you go spring under for obvious reasons.

Click to expand...

So I agree 100% with everything you have said except the spring won’t move the axle tube anywhere, it would be in the same spot at the same ride height, thus hitting the frame with the axle at the same bump travel? A “C”notch would get you more up travel but I don’t see a SU changing up travel at all.

roostinyfz said:

So I agree 100% with everything you have said except the spring won’t move the axle tube anywhere, it would be in the same spot at the same ride height, thus hitting the frame with the axle at the same bump travel? A “C”notch would get you more up travel but I don’t see a SU changing up travel at all.

Click to expand...

if you mount the spring 4 inches lower ( diameter of axle tube) but arch and lengthen the leaf spring to provide the exact same ride height, the center point of the leaf spring has to travel 4 inches farther during compression for the spring to get to the farthest point north during uptravel.

it also has to travel 4 inches less to get to full droop, being that its new mounting point is 4 inches lower than previous mounting position.

for the sake of simplicity, you end up with the same total wheel travel after changing the spring mount, but if before the change, you had 8 inches of uptravel and 12 inches of down travel.

after the change, you now have 12 inches of uptravel and 8 inches of downtravel.

or maybe I'm not explaining this properly.

shit.. just running a slightly longer coil spring and changing the eyelet on the coilover did the same thing on the front of my truck.

before the change, I could stuff a 37 with zero fender contact, after the change, well, let's just say my truck is shedding some carbon fiber tomorrow so I don't pop the fender off again.

where I absolutely could have fit a 39 before the change, I'm going to have to switch to a one-piece front end now if I have any hope of putting bigger tires on the truck and still maintain the ability to stuff the tire without bumping it to limit travel, thus robbing the 2 inches of travel that I gained with the change.

zombiekiller said:

if you mount the spring 4 inches lower ( diameter of axle tube) but arch and lengthen the leaf spring to provide the exact same ride height, the center point of the leaf spring has to travel 4 inches farther during compression for the spring to get to the farthest point north during uptravel.

it also has to travel 4 inches less to get to full droop, being that its new mounting point is 4 inches lower than previous mounting position.

for the sake of simplicity, you end up with the same total wheel travel after changing the spring mount, but if before the change, you had 8 inches of uptravel and 12 inches of down travel.

after the change, you now have 12 inches of uptravel and 8 inches of downtravel.

or maybe I'm not explaining this properly.

shit.. just running a slightly longer coil spring and changing the eyelet on the coilover did the same thing on the front of my truck.

before the change, I could stuff a 37 with zero fender contact, after the change, well, let's just say my truck is shedding some carbon fiber tomorrow so I don't pop the fender off again.

where I absolutely could have fit a 39 before the change, I'm going to have to switch to a one-piece front end now if I have any hope of putting bigger tires on the truck and still maintain the ability to stuff the tire without bumping it to limit travel, thus robbing the 2 inches of travel that I gained with the change.

Click to expand...

So I could be wrong and trying to make sure my thought process is correct, but I think what you are saying is true if the limiting factor for uptravel was the leaf spring hitting something at bump. But even a spring over’s travel is limited by the axle hitting the frame, not the leaf hitting the frame. I believe the axle to frame distance never changes (at a given ride height) in a SO or SU situation on the raptor and the travel is always limited by the axle hitting the frame? I could be wrong but this is what I have been told and thought it made sense but let me know if I’m wrong. I believe the biggest benefit of a SU on the raptor is actually the softer springs make the shocks much easier to tune, and better quality of motion if that makes sense.

roostinyfz said:

So I could be wrong and trying to make sure my thought process is correct, but I think what you are saying is true if the limiting factor for uptravel was the leaf spring hitting something at bump. But even a spring over’s travel is limited by the axle hitting the frame, not the leaf hitting the frame. I believe the axle to frame distance never changes (at a given ride height) in a SO or SU situation on the raptor and the travel is always limited by the axle hitting the frame? I could be wrong but this is what I have been told and thought it made sense but let me know if I’m wrong. I believe the biggest benefit of a SU on the raptor is actually the softer springs make the shocks much easier to tune, and better quality of motion if that makes sense.

Click to expand...

you are correct.

however, in order to make the ride height in a spring under scenario the same when compared to a spring over scenario, you have to arch and lengthen the spring to provide the same ride height as a deaver +3 spring over, because the center of the spring is now mounted 4" inches farther away from the frame of the truck. in this scenario, you're actually creating more distance from axle tube to frame at ride height when maintaining an identical rideheight to when the spring was over the axle.

zombiekiller said:

you are correct.

however, in order to make the ride height in a spring under scenario when compared to a spring over scenario, you have to arch and lengthen the spring to provide the same ride height as a deaver +3 spring over, because the center of the spring is now mounted 4" 4 inches farther away from the frame of the truck. in this scenario, you're actually creating more distance from axle tube to frame at ride height when maintaining an identical rideheight to when the spring was over the axle.

Click to expand...

So I think we are saying the same thing really.

zombiekiller said:

you are correct.

however, in order to make the ride height in a spring under scenario when compared to a spring over scenario, you have to arch and lengthen the spring to provide the same ride height as a deaver +3 spring over, because the center of the spring is now mounted 4" 4 inches farther away from the frame of the truck. in this scenario, you're actually creating more distance from axle tube to frame at ride height when maintaining an identical rideheight to when the spring was over the axle.

Click to expand...

Yes I agree with this, but on a spring over the up travel is the distance between the top of the axle tube to the bottom of the frame. At the same ride height (truck not lowered 4” which it would be without lengthened and arched springs) mounted 4” lower below the axle, the up travel is still the distance from the top of the axle tube (which actually hasn’t moved) to the bottom of the frame. Although the spring is mounted 4” lower (a lower center of gravity for the truck, another benefit) results in a net same up travel. I think we are probably saying the same thing in a different way, sorry to hijack the thread.

roostinyfz said:

a spring over’s travel is limited by the axle hitting the frame, not the leaf hitting the frame. I believe the axle to frame distance never changes (at a given ride height)

Click to expand...

You are correct

No worries about hijacking the thread...I got what I needed a few posts back. Besides, the spring info is good stuff.

I’m trying to map a plan on how to get from stock to modded, and knowing where to try and end up is always helpful!

Jonny V said:

https://www.amazon.com/dp/B00D61AELU/?tag=fordraptorforum-20

I’m not too sure about ReadyLift, but the mount system they have looks nice. I like that big plate they’re using to reinforce the frame. Would still have to provide your own bump stop cans...

Click to expand...

I do wonder if the kit is made in the USA or elsewhere and that should be a concern. But you can go with the Forged Offroad bump stop kit for $699 and its a proven bump stop made in California.

https://forged-offroad.com/product/...ord-raptor-rear-bump-stop-kit/?v=7516fd43adaa

@Lynxs961 would be more than happy to answer any questions on their bump stop kit and will more than likely hook you with a even better price


--