Bump Stops?

so i saw a video this weekend where they say the new 4runner doesnt have any bump stops in the traditional sense mounted to the frame. they have moved to a top of the shock tower bump stop and people are pushing the bump stop past the shock tower mount point aka like the 24 taco.

there is a thread on the tacoma world forums about this https://www.tacomaworld.com/threads/shock-based-bump-stop-failure.839665/



https://www.youtube.com/watch?v=T8gRnf0I7U8

 

So glad Toyota is working out a lot of the kinks of the new design with the Tacoma before the 4Runner.

At this point, wouldn't be surprised if Toyota pushes the 4Runner release again until next August.

No bump stops for their two main offroad vehicles. Mall crawlers win again. Lol

 

This is a complete managerial fail. Why are other TNG vehicles getting 1 or 2 BS, and others getting none?
Much like a LOT of economic entities and policies in the world today, I fear Toyota corporate is fractured and needing to clean house.
Aftermarket guys are licking their chops....

 

Can't wait to see the warranty claims getting denied because you went offroad for an afternoon.

 

American designed trash - these new Toyota trucks are

 

1. Hydraulic seats in Tacoma look gimmicky af.
2. Removable stereo in dash is cheesy af.
3. 52 TRD logos on TRD version looks stupid af.
4. Big ass badging letters on dash look ugly af.
5. No bump stops is seriously wtf.

The rest I'm ok with. Maybe all part of their grand plan to get more people to buy a Land Cruiser.

 

A shock-based bumpstop is going to serve the same purpose as a frame-mounted one. It's a shit implementation with that hat design but the only bad thing about bumps on the shock is that you can't easily tune them to your lift.

Either way, you should not be hitting stock bumpstops they're not designed for that shit. Tune your suspension properly and drive within the limits of your vehicle. You aren't breaking that hat from normal use you're breaking it slowly each time you hit too hard.

 

If a shock based bump can't perform like a stock 4th and 5th gen without damage? Sorry major FAIL 2 piece top hat? FAIL.
Raptors and Broncos do not have bumps, but they don't fail after 20 offroad miles. ICON Vehicle Dynamics has been making Toyota truck suspensions for decades. So for them to report this on YT, then it's a problem. Not just tuning.
Trusting newer, lighter and poorly made/designed products in an offroad setting is not safe. Yes shock tuning is important, but having a brand new truck that needs shock tuning to do what it's advertised to do? FAIL. Buy em up ya'll, that way there will be plenty of 4ths and 5ths around for us used market guys.
https://youtu.be/xh3-09v8MYo?si=mSKC4dPcEgEA8KRe

 

Ultimate offroad vehicle?
https://youtu.be/kxhfYRxUE2E?si=d39WQRIrxub8Pivy

 

I’ve always assumed that the frame mounted bumpstop was there as an “end of the line” measure to protect the suspension as much as possible when a hard hit occurs. Even when I look at the “bump” rubber itself on my 4runner, it’s on a bolt on structure that itself would deform before forces would start deforming the frame rail.

I’m sincerely wondering if Toyota is going to say these failures are by design. That it’s a sort of “fusible link” that tells you you’ve gone too far, before you end up with a bent shock tube or damage to the strut tower weldment (like wallowed out bolt holes or cracks in the steel).

While there would be a certain logic behind a tophat designed in that way, it would also be toyota blowing smoke up everbody’s ass. The LC model needs frame mounted stops, but not the tacoma or 4runner? That would sound like BS if this is what they intended.

Am I right to conclude frame mounted bump stops have greater ultimate strength than a design that relies on purely on the suspension?
It’s not just the strength that’s the issue, it’s the fact that nothing is protecting the suspension system anymore… and that the suspension has less usable range since they needed to create a shock with super tight damping to slow down an impact before it goes into the hard components. Lots of complaints already of “bottoming out” on roads, that are actually the shock transitioning into bump damping range.

This suspiciously seems to be a purposeful decision to justify saying the LC and other models are “stronger”. It’s a shitty strategy to make your lower products worse than they used to be, just to make your higher trim levels “better”. It’s also, in a way, Toyota calling out customers by telling them they weren’t going to use that strength at the mall anyway lol.

 

I'm definitely not saying it's a good design, but you are correct that factory bumps are a hard rubber last resort to prevent suspension damage. It doesn't matter if they're a-arm mounted or shock mounted, they both absorb the energy and both are equally valid solutions where done correctly. Where Toyota went wrong is it appears their shock bumpstop isn't strong enough to resist compression and the forces are transferring into the top hat.

I don't think they're playing the stronger card because they offer 6 vehicles on the same TNGA-F platform serving different market segments and none will struggle to sell. It's probably just as simple as the LC being heavier vehicle with more weight on the front axle than a Tacoma.

 

Ok Yoda.

 

I know you have more experience with this sort of stuff than I do, which is why I’m asking your thoughts on my train of logic regarding my “fusible link” theory….

With regard to suspension based bump-stop designs, am I correctly understanding that the
bump impact load path starts with the shock body, and ultimately end up at the welded strut tower structure and lower shock bolt mount?

Assuming that’s correct, if any of those components or structures bend or break, you end up with a deformations in the suspension components that could cause sudden changes in tire angles… or outright collapse of of the suspension if the single shear lower shock mount breaks. This could possibly end up as a “controllability problem that could lead to loss of control and death” in the eyes of NHTSA. Given the potential for a nasty recall, would it make sense to design a fusible link into the system?

The broken retainers for the shock piston that the Tacoma’s are experiencing look suspiciously like a designed failure point to me. It appears to me that they only transmit damping forces to the frame. If you allow the piston retainer cap to break off, you lose damping, but the geometry of the suspension is not dangerously affected. In fact, the bump damping zone designed into the shock, could be there specifically to induce the failure of that cap! (I just thought of that now!!! Mind blown!!! Lol).

If this is all “as intended”, then personally I think this bump stop scheme is mis-applied on a vehicle that is being marketed as an off-roader. Could be completely fine for a work pickup truck, or a road car though.

edit: seems most pictures of 4runners show the single shear lower shock mount. But the tacomas now appear to be getting double shear mounts. My prediction is that 4runners will ship with double shear, considering that they will responsible for taking constant hydraulic impact forces from that bump damping zone.

 

That's probably the second worst possible outcome for a fusible link because the broken part lets the strut impact the bodywork. The only worse would be dropping out the bottom so it really looks to me like they didn't expect it as a failure. As I said above, these aren't dirt road trucks that are breaking, it's people who test relatively hard, and each impact will weaken the part until it may rail in normal use.