Subaru Forester Owners Forum banner

1 - 20 of 22 Posts

·
Registered
2020 Sport
Joined
·
5 Posts
Discussion Starter #1
I purchased a draw-tite class III hitch but haven't installed it yet. I've read in a few places that aftermarket hitches that attach underneath to the frame like draw-tite and curt hitches may affect the vehicle's safety features, such as the rear crumple zone and impact features, because of torsional stress on the frame (or something like that). Is this still an issue with aftermarket hitches?

Also, for those of you who have a curt or draw-tite hitch, does the weight of it make the back of the vehicle sag or sit lower?

I would like to have the hitch for carrying bikes now and then, but I'm also concerned about safety and stress on the vehicle. I will figure out another way to transport the bikes, possibly by using the rails, if the hitch will be an issue.
 

·
Registered
2012 Forester X Auto
Joined
·
1,487 Posts
@JKimmer
I've installed both the OEM and Curt hitches, and they pretty well attach exactly the same.

The crumple zone / safety problem "issue" is more likely a personality defect than an actual problem, or there would have been lawsuits long ago.
I think it more likely that the additional material would add some additional structural integrity, rather than cause a compromise.

If you read enough, you will eventually find someone who has found a problem with everything.

Hitches aren't heavy enough to cause any noticeable "sag".

As to carrying bikes, the roof or hitch both work, but in the former, you have to lift the bikes up while hopefully not dropping them on a rather flimsy roof, and with the hitch, it makes rear hatch access less convenient. That's the only real issue with using the bike hitch method.
 

·
Registered
2020 Sport
Joined
·
5 Posts
Discussion Starter #3
@JKimmer
I've installed both the OEM and Curt hitches, and they pretty well attach exactly the same.

The crumple zone / safety problem "issue" is more likely a personality defect than an actual problem, or there would have been lawsuits long ago.
I think it more likely that the additional material would add some additional structural integrity, rather than cause a compromise.

If you read enough, you will eventually find someone who has found a problem with everything.

Hitches aren't heavy enough to cause any noticeable "sag".

As to carrying bikes, the roof or hitch both work, but in the former, you have to lift the bikes up while hopefully not dropping them on a rather flimsy roof, and with the hitch, it makes rear hatch access less convenient. That's the only real issue with using the bike hitch method.
Got it, thank you! It feels better knowing the OEM and Curt are installed the same way. I'm assuming the same is true for draw-tite since it is very similar to the Curt. I only went with draw-tite because that's what etrailer recommended in Q&A to someone because of the j-pin and weight distribution capabilities.
 

·
Registered
2012 Forester X Auto
Joined
·
1,487 Posts
You're welcome.
The major differences are probably more marketing/individual preference (my dog's better than your dog;-)
Since all three are bolt on's, they kinda have to be the same or no fit.
There are total load differences in some hitches, but the Forester has such a low tow rating, a super duty hitch is just overkill.
If you are going to install it yourself, bring some patience and take the car to a spray wash and clean the underside, or you will wish you had...
Good Luck!
 

·
Registered
2014 2.5i Touring Auto-CVT
Joined
·
285 Posts
I have the Drawtite Class III. Doesn't drop the back at all. Difference between it and the Curt is the Curt manufacturer requires a load strap when using the hitch as a carrier and the Drawtite does not. This is a problem if you have the rear spoiler. Most people ignore the requirement without issue. I just don't want to be the first one that does.
 

·
Registered
2020 Sport
Joined
·
5 Posts
Discussion Starter #6
I have the Drawtite Class III. Doesn't drop the back at all. Difference between it and the Curt is the Curt manufacturer requires a load strap when using the hitch as a carrier and the Drawtite does not. This is a problem if you have the rear spoiler. Most people ignore the requirement without issue. I just don't want to be the first one that does.
So you use a load strap even with the draw-tite?
 

·
Registered
2014 2.5i Touring Auto-CVT
Joined
·
285 Posts
So you use a load strap even with the draw-tite?
No it's not required by Drawtite. If I had a Curt I would, not because I think it's necessary but because ignoring the manufacturer's instruction would increase my liability in the, albeit unlikely, situation of a failure. Also, there's no way to attach a strap with a rear spoiler.
 

·
Registered
2019 Forester Limited
Joined
·
545 Posts
@JKimmer , just a couple clarifications to what's been posted.

The OEM and Curt hitch are totally different in how they install in the 2019+ model year Foresters. They may have been the same on earlier model years, but not for your 2020.

Both OEM and Ecohtich replace the rear bumper beam underneath the plastic bumper fascia and slide inside the frame members. All others leave the bumper beam in place and bolt directly to the outside of the frame members. The external mount of the Curt provides a simpler installation (not saying better or worse, just simpler).

EDIT:

I'd earlier expressed doubts about slides from Subaru Canada and whether they represented an official stance by Subaru. @RawLand nicely called my perspective on the slides, "interesting", (was probably thinking of more colorful words) and provided an official video from Subaru seen later in this thread. It changed my mind.

Subaru cautions that an externally mounted hitch, like the Curt, may impact performance of the rear crumple zone. They don't present data showing how it may impact, and that's not really their job. They designed the structure, as well as a hitch to work with it. My take on this is anything that causes the dynamics of an energy absorbing structure meant to ensure my safety to change, isn't something I'm willing to mess with. That an externally mounted hitch will change a safety structure's performance in unknown ways would be enough to steer me away from the design, if I were faced with that choice today.

I self-installed Curt on my Toyota, and Ecohitch on my Forester. They both work just fine. I liked the idea of having most of the hitch structure up and out of the way on my Forester, and it provided a little more ground clearance compared to the Curt. The OEM and Eco cost more to purchase, and likely more to install, than the Curt. Up to you whether the advantage I perceive applies to you and is worth the extra cost.
 

·
Registered
2019 Forester Sport CVT
Joined
·
475 Posts
Interesting perspective on the materials produced by Subaru of Canada. I'd have to think that Fuji Heavy Industries would review and approve all such materials, just like how manufacturers review and approve all American dealer advertisements. Probably the corporate materials are even more scrutinized.

 

·
Registered
2020 Sport
Joined
·
5 Posts
Discussion Starter #10
Interesting perspective on the materials produced by Subaru of Canada. I'd have to think that Fuji Heavy Industries would review and approve all such materials, just like how manufacturers review and approve all American dealer advertisements. Probably the corporate materials are even more scrutinized.

This video is what got me a little worried to begin with, but the consensus here and elsewhere online seems to be that aftermarket hitches are fine and any effect they may have is insignificant.
 

·
Registered
2019 Forester Sport CVT
Joined
·
475 Posts
What are the odds of a high speed rear end impact anyway? People are much better about not staring at their cellphones. Aren't they?

I understand the review by auto manufacturers of all materials because of years of listening to Ed Wallace. (www.insideautomotive.com) Subaru Canada represents the official Fuji Heavy Industries position.

I'm always inclined to go with changes that suit my individual desires, suspension, tires, oil & filters, etc... A properly collapsing impact absorbing zone in a lightweight vehicle, like the Forester, is all that protects us from a F-250 Stuper Doody driver staring at a cellphone. I'm not interested in reducing impact absorption, even if only a couple percent.
 

·
Registered
2019 Forester Sport CVT
Joined
·
475 Posts
The OP asked about rear suspension compression with a hitch and carrying a load. I guess that depends on the load.

I had a 200+ pound Subaru salesman sit on the rear edge of a 2019 Forester and carefully measured the rear wheel well with him in and out. The difference was 1/2".

Here are photos of my Forester loaded and unloaded.





No discernible difference in rear ride height. Add luggage filling rear and maybe a tiny bit of compression.
 

·
Registered
2019 Forester Limited
Joined
·
545 Posts
Hey @RawLand, the video you provided is a quite a bit more "official" than the slides I'd seen. Honestly, they were pretty amateurish and I seriously doubted their veracity. I would not have let a presentation of that poor quality leave my group without revision back in the day.

The video clearly reflects an official Subaru stance, so I'm going to retract my earlier comment. I still find it odd that the aftermarket folks haven't taken a stance, or tried to refute. I'll edit my prior post as well.
 

·
Registered
2019 Forester Touring
Joined
·
153 Posts
This video is what got me a little worried to begin with, but the consensus here and elsewhere online seems to be that aftermarket hitches are fine and any effect they may have is insignificant.
The video states 3000 pounds capacity. The 2019 manual says 1500. The specs of the three hitches on etrailer.com say ~3500. I contacted etrailer for an explanation since the manual says 1500. The answer basically was the hitches themselves are rated for 3000+ while Subaru's published limitation is more based on maximum total vehicle payload - 5 adults plus luggage plus 1500 pounds of trailer. Makes sense to me.
 

·
Registered
2020 Sport
Joined
·
5 Posts
Discussion Starter #15
The OP asked about rear suspension compression with a hitch and carrying a load. I guess that depends on the load.

I had a 200+ pound Subaru salesman sit on the rear edge of a 2019 Forester and carefully measured the rear wheel well with him in and out. The difference was 1/2".

Here are photos of my Forester loaded and unloaded.





No discernible difference in rear ride height. Add luggage filling rear and maybe a tiny bit of compression.
Off topic, what kind of tires are those? They look like an all-terrain/off-road type. If so, do they affect fuel economy, comfort of street driving, or anything of that nature? They are pretty slick looking, I may have to get similar tires when the original ones wear out.
 

·
Registered
2019 Forester Sport CVT
Joined
·
475 Posts
Off topic, what kind of tires are those? They look like an all-terrain/off-road type. If so, do they affect fuel economy, comfort of street driving, or anything of that nature? They are pretty slick looking, I may have to get similar tires when the original ones wear out.

People here tell me that they do affect mileage. I think it is my driving that affects my gas mileage the most.
 

·
Registered
2002 Forester 5MT, 2020 Forester Touring
Joined
·
104 Posts
My take is that the video about the difference in torsional stress on the frame between the OEM (or Ecohitch) mounting approach and the Curt/Drawtite mounting approach is a little misleading. Here is how I think it would work.

If the rear were to be hit at the receiver tube level, it would tend to twist the rear of the frame down, as indicated in the video, with either type of hitch attachment. The torsional stress on the frame (I use the term frame loosely, meaning the sections of the unibody designed to provide strength, such as the rectangular sections to which the hitches are mounted) would be related to the force of the hit times the length of the lever arm, which is the distance between the mounting location and the receiver tube. That distance is pretty similar for either type of mount. The OEM style mounts a bit higher on the frame, but the receiver tube is also a bit higher. So I think the torsional stress on the frame for a hit at the receiver tube level would be about the same for either type of hitch mount.

If the hit on the car is higher, on the bumper itself, then torsional stress on the frame is not a real factor, but there is a question of whether the original bumper beam or the hitch mount beam does a better job of transmitting the stress of the hit into the crumple zone. That has been discussed in other threads, with some claiming that the ultra high strength steel of the original bumper beam is better and some claiming that the hitch bars have enough strength to work just fine. I don't have an opinion to weigh in on that, though I think Subaru claims to have tested the crash performance of the hitch, so presumably it works OK. The Curt/Drawtite style of mount would leave the original bumper bar intact, largely preserving the original safety performance for the situation of a hit on the bumper. The only potential impact I can think of for the Curt/Drawtite style mount is that the underside of the frame would be reinforced a bit, reducing the amount of crumple, and hence energy absorption, in that section of the frame. I can imagine that would increase the load a bit on the forward portions of the frame, but that is not the same as the torsional load issue in the video.

So in summary - just my opinion - there is likely to be little difference in crash safety between the OEM style hitch mount and the Curt/Drawtite style hitch mount.
 

·
Registered
2019 Forester Limited
Joined
·
545 Posts
Nice thought experiment, but I can’t share your opinion. Subaru went with a completely different hitch design for the new Forester platform. Ask, Why? Why did they throw out a simple design that had worked well on earlier models and could be used again on the new platform with just a few tweaks? Because it compromised crash performance, that’s why. Manufactures are frugal and avoid reinventing the wheel whenever possible. No way they created a new design, just for the heck of it. They did it for a reason.

They don’t explain it well. Non-linear dynamics are complicated. They tried to simplify it for public consumption and failed. Heck, they take pages and pages to explain the simplest of things in the user manual and still butcher it, why expect anything different for something complex?

anyway, just my opinion. :)
 

·
Registered
2002 Forester 5MT, 2020 Forester Touring
Joined
·
104 Posts
What you say about manufacturer behavior is hard to argue with. I just have trouble buying the argument about torsion in the video. As I continue to think about this, I think there may actually be more torsion on the frame from the OEM style mounting than the Curt/Drawtite style mounting, at least right at the mounting location - if the vehicle were to take a hit in the receiver tube. But maybe the reinforcement of the frame created by the Curt/Drawtite style mount is in a crucial zone for energy adsorption when the hit is to the bumper, which I suspect is the test condition.

At least Subaru still provides all the access holes needed for the old style hitch mount (some, though not all, of which are also used for the new style mount), so we can pick our poison!

Do you know when Subaru switched the mount style? The SJ is the same style mount as the SK, and my SF has the old style, but I don't know when they made the change.
 

·
Registered
2018 Forester XT Limited CVT
Joined
·
495 Posts
I think there may actually be more torsion on the frame from the OEM style mounting than the Curt/Drawtite style mounting, at least right at the mounting location - if the vehicle were to take a hit in the receiver tube. But maybe the reinforcement of the frame created by the Curt/Drawtite style mount is in a crucial zone for energy adsorption when the hit is to the bumper, which I suspect is the test condition.
Assuming the car is rear ended by another car and the car in the back impacts the bumper of the car in front, instead of impacting the hitch ball, I can see the crumpling being different between the two hitch types. In the "mount to frame" aftermarket situation, the video shows the bumper beam still in place. I guess the situation is just not tested.
 
1 - 20 of 22 Posts
Top