Car-of-the-Week status means it's our 2010 Honda Insight's turn to be put in a compromising position so we can have a look at the suspension. This won't hurt a bit.
Seeing as how the Insight shares significant chucks of undercarraige with the Honda Fit, one would think that we wouldn't see any major surprises. That's partially true, but there are some differences and I've included a lot more detail this time.
Up front, the Insight shares a lot of parts with the Fit. It's your basic MacPherson strut set-up with a coil-over spring and a single lower ball-joint. The steering pivot axis is illustrated by the thin yellow line.
In case you've wondered, a MacPherson strut suspension has no upper control arm because the strut itself is very rigid in the lateral direction, and can therefore define the path along which the suspension moves. To do that it must be bolted firmly to the steering knuckle with two large bolts (yellow), making the whole affair one solid, albiet telescopic, piece all the way to the pivoting mounting point at the top.
Struts also act as dampers, of course, so they have all the internal valving and oil that a shock would have. But even though all the parts appear interchangeable, the spring and internal strut damping of this Insight will be different from the Fit because of differences in vehicle weight and weight distribution.
By comparison, shock absorbers are relatively flimsy because they are not asked to take the lateral loads that are necessary to actually locate and define the movement of a suspension. Of course they do just fine at "absorbing shocks" when subjected to pure compression and tension loads, and they can be smaller and lighter because supesnion arms and/or links does the suspension locating for them.
The lower end of the Insight's suspension is located by an L-shaped lower control arm with a single ball joint at it's outer end. The steering rack and steering arm (green) are located behind the ball-joint because it's generally not possible to mount the steering rack ahead when a tranverse engine and transmission mounting is used.
The front subframe bolts directly to the unibody, a move that saves money and weight while it improves steering feel and direct response. This isn't the path to ultimate road isolation and extreme cabin silence, but Honda has never prioritized such things to the extent that some of their home-market competition has done.
The Insight's front stabilizer bar is direct-acting, as evidenced by this long, slender link that connects directly to the strut housing.
In most cars the upper strut mount is obvious when you pop the hood, but the Insight's hood is so short that the sturt-top is actually hidden in a pocket under the base of the windshield.
The Honda Insight's brakes use a single-piston sliding caliper and a one-piece ventilated rotor. The term "regenerative braking" is associated with hybrids, but that's an independent electricfied version of engine braking that has nothing whatsoever to do with the standard brake system, which operates in an utterly normal way.
The unmoving rigid half of a sliding caliper bolts directly to the suspension knuckle (yellow) and holds the pads in place. The single hydraulic piston that does the work is implied by the single cylindrical bulge (green) in the caliper body. The moving half of the caliper follows a pin (green line) as it slides back and forth as the brakes are applied and released.
The Insight's rear suspension is a twist-beam axle, a semi-independent form of suspension that is very space efficient.
This axle pivots around two mounting bushings, represented here by the green circle and one like it on the other side. These are the only two mounting points to the body, in fact. OK, the shock absorbers have internal stops to prevent the wheels from extending down so far that the springs fall out if you jump the thing off a ramp -- I'll give you that. But the two forward pivots are the only points at which this type of axle is truly located.
It's basically like a very wide motorcyle swingarm with two wheels on the outside instead of one clamped in the middle.
The single c-shaped channel (white) spans between these arms, and it's designed to be twisty from one side to the other; hence, twist beam. It's categorized as semi-independent, however, because it's all one piece; what happens on one side has a limited effect on what happens on the other side.
Here's another look at the twisty cross beam and the rigid arms. A lot of times you won't see a rear stabilizer bar on one of these. But that's not really true because what you're looking at, in effect, is one giant stabilizer bar with wheels bolted directly on the ends.
The beauty of this suspension type is the packaging potential, because the slender cross beam (yellow) doesn't need much space. This leaves room for a huge well (green) between the tires of sufficient size to house the Insight's hybrid battery pack, spare tire, tools and a bit of storage.
Those arms need to be rigid, and that plays right into the hands of the spring and shock mounts (yellow and green, respectively) which consist of welded-on pieces that act as gussets for extra stiffness.
Did I say this suspension has no rear stabilizer bar? Well, that depends on how you look at it. The flexy c-channel itself amounts to a stabilzer bar, but it also houses a supplemental round torsion bar (yellow) that's there to fine-tune the torsional stiffness of the entire assembly. After all, the design engineers can't predict exactly how much stiffness will ultimately be needed and the suspension tuning engineers need a way to dial-in the appropriate amount of roll stiffness once they get their hands on a running prototype.
The rubber bush shown is slipped over the center of the bar to keep it from rattling around and making noise over bumps.
Here's where this supplemental torsion bar disappears into the side-arm where it is firmly welded in place (I think -- can't see in there).
The nub ends of the supplemental torsion bar (green), and the welds that hold it in place, are clearly visible. Honda's continued use of drum brakes in the rear speaks for itself.
Unlike a motorcycle swingarm, the two main pivot bushings are NOT oriented perpendicular to the direction of travel. Cocking them at an angle (looks like 30 degrees here) helps balance the need for high lateral stiffness when cornering against the need for a little fore-aft compliance to mitigate harsh road impacts.
All of this sits on 15" aluminum alloy rims and 175 / 65 R15 low roll-resistance tires that weigh 34 lbs mounted and ready to roll.
Dan Edmunds, Director of Vehicle Testing @ 2,235 miles
wobbly_ears says:
01:35 PM, 07/22/09
Again, another homerun Dan!
corvette says:
01:39 PM, 07/22/09
Given what I've read about the ride and handling of the Insight, I think "Suspension Workaround" would be a more apt feature.
clarkma5 says:
02:12 PM, 07/22/09
Oof, I would not be jacking up a car on a slope like that ><
I know that semi-independent torsion beams are extremely common, but I've always wondered why it isn't more popular to simply forgo the center twist beam and have a full independent and space-saving suspension. Is it merely a question of dealing with the lateral loads?
7driver says:
02:23 PM, 07/22/09
The Mazda6 has had 2 go-arounds as CotW. Has it had a suspension walkaround yet?
hurls65 says:
02:30 PM, 07/22/09
Very cool... I must say I enjoy these even on cars that aren't all that interesting to me... it's instructive to see the engineering decisions and trade-offs that are made on cheaper cars (as opposed to seeing all exotic/semi-exotic cars with fancy forged aluminum multi-link set-ups -- not that I don't like those too).
Thanks Dan.
actualsize says:
02:34 PM, 07/22/09
@clarkma5: fully independent suspensions have a lot more parts than one of these. They cost a lot more money and they're more complicated to assemble on the line. And even the space-saving independents eat up more real estate than on of these.
But a twist beam axle only works on a lightweight front-drive vehicle. And the compromise between agility and comfort is hard to balance properly.
@7driver: I was out of town both weeks. It's on my list!
subytrojan says:
03:17 PM, 07/22/09
Wow, Dan! I wish I knew what you know!
clarkma5 says:
03:50 PM, 07/22/09
actualsize: I meant to use the same sort of packaging as the twist beam semi-independent rear, just without the twist beam, thus creating a simple, light, and compact independent suspension that consists of 1 arm per side that pivot from in front of the wheel. I'm well aware that a full strut, multi-link, or double-wishbone independent setup in the rear is much more expensive and bulky.
GT5000 says:
05:12 PM, 07/22/09
I can't believe that the $14,000 Focus gets slammed for using drum brakes, and when Honda does it on a $20,000 hybrid nobody breathes a word about it...
billt9 says:
06:24 PM, 07/22/09
Wow this looks a lot cheaper in materials and assemblies than the $50,000 cars.
What is that thin thin blue painted steel panel the suspension is bolted to?
I suppose it's adequate durability for a 2700 lb car.
And this is how it got to be merely 2700 lb in the first place. Even with the additional weight of a battery.
thegrocer says:
07:37 PM, 07/22/09
Re: Focus Drums - Probably because the Civic gets discs on the EX...but the LX and DX all get drums. The Focus is an SES and competes with the EX and the parts were there to do it from the SVT (as far as I know still a straight swap and available from Ford racing listed for the ZX3/4/5 2000-2008).
thegrocer says:
07:57 PM, 07/22/09
http://www.fordracingparts.com/download/instructionsheets/FordInstShtM-2300-ZX3.pdf
Instruction sheet for SVT disc conversion all the way around...whether it works on the 2008+, I dunno but my understanding is they changed damping and bushing but not the overall suspension...no suspension walk around on the Focus, so I can't comment on the differences between it and the 1/1.5 gen (my wife has an 06 I do all the maintenance on)
kyolml says:
09:07 PM, 07/22/09
For this of being $20k, compared it to Prius for $22K (which the parts look more sophisticated), it doesn't look any attractive to me.... Guess people know it so (Prius outsells it more than twice.....)
kevinlch says:
10:50 PM, 07/22/09
@clarkma5: 1 arm per side doesn't give you enough lateral stiffness
GT5000 says:
06:16 AM, 07/23/09
@thegrocer
The Toyota Prius, which the Insight competes with, has four-wheel disc brakes. So isn't this actually the same as the Focus-Civic comparison.
dougtheeng says:
06:56 AM, 07/23/09
car + slope = danger?
actualsize says:
07:16 AM, 07/23/09
@clarkma5: I'm with you now. But kevinlch is right - an arm by itself couldn't stand up to lateral loads without additional links or, in this case, a beam and copious gusseting that ties it to the other side.
banhugh says:
07:18 AM, 07/23/09
Wow!!! How much does this website get from Honda for such a presentation?
17 photos???????
Who cares about the suspension of a crappy little half hubrid?
Not even the GT-R had such a long suspension walk around!!!
canadia says:
07:58 AM, 07/23/09
@banhugh:
1. Edmunds didn't receive anything from Honda for this walkaround.
2. The amount of photos used is up to the discretion of the editor; i'm sure they post as many as they feel necessary to illustrate their points. Also, 17 is not unusually high for a suspension walkaround.
3. In all likelihood, you're too lazy to spend two minutes reading what others have said, so i'll summarize briefly by quoting one of the above posters: hurls65 said: "Very cool... I must say I enjoy these even on cars that aren't all that interesting to me... "
4. Actually, the GR-R's suspension walkaround was so thorough and voluminous that it required two separate blogs. And, for the record, it contained 24 pictures.
P.S.: Please never reproduce. Thanks.
canadia says:
08:01 AM, 07/23/09
Edit: in no. 4 of my above post, it should read "GT-R" rather than "GR-R."
Oh and thanks again Dan for another informative walkaround. They're my favorite blogs, bar none.
foxtrot685 says:
08:23 AM, 07/23/09
Seriously, I think you all should do a suspension walk around on the Ford Focus. Its rear suspension is quite sophisticated for a $14,000 car, and I think it would shock people how complex it really is. Heres a hint: it is one of the few cars in its class that doesnt use a torsion beam rear suspension...
foxtrot685 says:
08:28 AM, 07/23/09
@ the grocer: the rear disc conversion does work on 2008+ Ford Foci. All that is required to my understanding is you have to drill some extra holes when mounting the backing plate because the OEM holes do not line up. But yes, ultimately the rear disc conversion does work on new foci!
m_thrizzle says:
09:25 AM, 07/23/09
So the Insight doesn't have regenerative braking?
joefrompa says:
10:30 AM, 07/23/09
Very basic and un-fancy. The rear setup dissapointed me, until i read that it basically allowed the rear well to house the hybrid system, which probably also improves the front-2-back weight-allocation of this car.
Still, this thing wasn't built for handling and it clearly is never going to urge it's drivers to explore it's limits. A bit dissapointing for Honda, who used to build cars with some excitement focus.
That subframe bolted to the body seemed interesting; I don't think I've ever seen that before. I like the concept, but holy crap that has got to transmit alot into the cabin.
Joe
banhugh says:
12:30 PM, 07/24/09
@ canadia:
1. You said it: "...for this walkaround"!!!
This was a "thank you" freebie I guess.
2. "17 is not unusually high for a suspension walkaround".
Let's see here:
Pontiac G8 G7 11 photos,
Challenger R/T 10 photos,
BMW 135i 10 photos,
Nissan 370Z 5 photos,
Nissan GT-R 14 photos.
All sports cars that people who read their long term blogs actually care more for suspension technical details (well apart from the Challenger folks). I am sure some other walkarounds had more photos and attention (Audi S5 with 18 or M3 with 20), but for the sake of humanity, 17 suspension pictures for a car without a rear sway bar?!?!?!?!?!?!?!?!?
3. I like walkarounds too. What I am saying is there is too much focus on this car's suspension due to it sucking handling abilities and harsh riding. Other cars that people bought them for their suspension as well as engine, etc, didn't even had a walkaround!
4. GT-R's suspension walkaround had 14 photos. What you fail to understand is the difference between a suspension and a brakes and tires walkaround.
Get your facts straight beforehand otherwise "in all likelihood" you will, be, ridiculed.
lucien4 says:
12:41 PM, 08/31/09
Great article. Just ignore whining about someone who hates car x but never drove it. Really interesting stuff.
Note that in Europe the Insight comes standard with 4 disc brakes and VSC on all models. First thing Honda should fix in the US.
actualsize says:
09:03 AM, 09/ 1/09
@m_thrizzle: The insight has regenerative braking. All hybrids (and electric cars) do, by definition.
But regenerative braking is more akin to engine braking in a regular car. It slows the cars some, but regular brakes are still necessary to really stop the car.
Here's the difference: The drag you feel from regenerative braking comes from the electric motor running "backwards" (in an electrical sense) and recharging the battery, therby saving the car's kinetic energy for re-use. The drag you feel from engine braking comes from the pistons moving up and down and continuing to pump air out the exhaust -- pure waste energy.
inlinesix says:
11:34 PM, 11/ 9/09
I find these walk-arounds really interesting. Its not like many have the opportunity to see such in-depth undercarriage information with pictures.
Its also interesting to see the way some manufacturers have engineered their cars to fit with changing society and technologies. I don't car if its a Focus, Insight or GT-R.
ciaociao says:
07:48 AM, 11/ 2/10
Dan,
I drive a 2010 Insight, and find the vehicle to have excessive sway in situations requiring quick course changes. Is it possible to have the rear torsion bar tightened to adjust for this, or modify the suspension in any way? I feel it is a safety issue, and it should be addressed by Honda ASAP. In general, the car is well built and handles nicely, however I have read reports of "inexact steering" which may be another way to describe what I am referring to as "sway". The car does seem to have a tendency to track a bit to the right as well, ever so slightly, with very touchy steering. I am just wondering if there are adjustments that can be made with this that would tighten the car up, and keep it more stable and ready for quick course changes. It is a subcompact, and an economy car so I can't expect it to perform with top grade in handling, but some improvements should be made to this, in the form of a recall for adjustment if it is possible. If you road test this car, you will see what I am speaking of.
wfalicoff says:
05:30 PM, 04/ 4/11
Hi Ciaociao,
We also own a 2010 Insight. I experienced the problem you describe when I was forced to move to the right at freeway speeds to avoid a collision with a high speed Porsche. I decided after this incident to modify the car to improve its emergency handling. First, we replaced the OEM tires with Nokian WRG2 185-60R15. This is slightly wider than the Dunlops but has little effect on the speedometer accuracy. I then looked into changing the struts and springs but the Mugen suspension available for the car (from King Motorsports www.kingmotorsports.com) was expensive and lowered the car around an inch. What we ended up doing was adding a rear 19mm sway bar from Progress Technology that was designed for the 2009/2010 Honda Fit. (see for example http://www.newedgeperformance.com/progress19mmrearswaybarkitfor2009hondafit.aspx). The Honda dealer in Huntington Beach, CA installed the sway bar (which is plug compatible with the 09/10 FIT and the Insight) for us at a very reasonable price. The improvement to the handling of the car was dramatic and I have not experienced the same problem as before. Of course the Insight does exhibit oversteer to begin with under certain conditions. With the rear sway bar this increases oversteer. But as we have the EX model with stability control I don't see this as an issue. We have driven the modified car on curvy mountain roads without incident under terrible weather conditions. I see no problem with the handling. The car tracks straighter with the wider Nokian tires. And the rear sway bar does improve the "straight-line" ride somewhat (an unexpected benefit). There is also obviously considerably less lean on turns. The handling is in my opinion now quite good.
There are other solutions to this problem if you can live with the lower ground clearance. (Tanabe and Eibach have replacement springs that improve the handling for a few hundred dollars plus labor)
I hope this is useful information.