Negative Camber Topic is solved

Post by **mrbrian200** » 23 Jul 2016, 22:26

90% of my driving is up a very poorly maintained bumpy/uneven county type road (county maintenance patches by 'shovel and drive over it with the truck' method, once about every 7-10 years they chip and seal, never been milled + trough on the RH side from local Amish horse-buggy traffic, very high center crown) ...since I was a small child I'm pushin close to 50 now...
I'm thinking about having the alignment shop set the front end negative camber less than spec or even at zero. I've been tweaking the toe setting up front to minimize side hop and tramlining up this specific road into town and have come to the conclusion the bit of instability I can't seem to get rid of might be due to the OE negative camber setting (it's presently set at -0.4 degrees both sides). Car drives awesome on better maintained highways/interstates but most of the time that's not what I'm on. I can tell when wheels are rolling parallel by peak in fuel efficiency within about a 5 degree range of angular adjustment on inner tie rod (the peak I found is 38.5 MPG (average) on open light rolling terrain highway cruise set @ 55. I use a small cable tie on the inner tie rod (like the hand on a clock) to gauge behavior at different settings.
Anyone with more technical background in this suspension: is there anything in the front end design that might specifically cause problems or introduce some undesirable instability on the S60 with less than specified negative camber? I'm not one to take corners or cloverleafs at excessive speed so a slight reduction in cornering ability probably isn't going to bother me, especially if I can get handling better tuned on this -ugh- very bad road that I traverse every single day.

Post by **tryingbe** » 24 Jul 2016, 05:01

You can get the camber to 0. I'm not sure that would help with bump steer due to bad roads. You can try, good luck.

Post by **mrbrian200** » 24 Jul 2016, 11:37

Sister's Jetta tracks with good ride quality up this particular road. Checked camber on it with a carpenters level: looks like it's set at zero. Jetta calls for about -1 degree if I remember correct, so I should see little less than 1/8" between bottom to top of rim from vertical on a 15" wheel parked on flat/level. That was done by a local shop that probably out of experience has learned to disregard OE specs in leau of accounting for local driving conditions/roads. I seem to remember a similar minor instability on that car before the strut service/alignment about 5 years ago. It wasn't 'terrible' but it was noticeable and somewhat annoying . I'll try it on the Volvo too. European designers probably don't realize just how terrible some US roads have become. And side roads that aren't applicable to state/federal road funds never were good.

Post by **mrbrian200** » 27 Jul 2016, 23:23

At 0 camber setting the car rolls so much more graceful over bumpy roads it isn't funny. Bump steer isn't completely gone but is way less. After a few runs up and down my test stretch of rural highway tweaking the toe setting to peak the econ (which is setting toe to account for bushing flare at speed) it feels really good to me now. Flat/open econ at 55 still in the neighborhood of 38-38.5. I was hoping for a measurable bump but that's ok. It not a Civic, it never will be, and if I wanted a Civic I would have bought one (nope). Optimal toe settings for econ and ride quality appear to converge now. With negative camber the best econ and best ride quality were at two different angles I would estimate about 0.15" or more different. I could get 38 highway with unsettled behavior on bumpy roads or adjust for better behavior but with lower highway econ around 32-33.

I recommend trying this depending on your preference. I'm sure on a track/course an expert would pick up a decrease in cornering ability/steering responsiveness in short order. But in the 20 or so casual/everyday type miles so far none of that is obvious to me.
But I'm not generally an aggressive driver. But I do like to punch it from a stop once in awhile. I was primarily after passing/merging/climbing power (I'll be in Colorado soon!) in a stylish, comfortable, moderately enviable ride that wasn't an aggressive looking sports car.

Oh, and.. I put LRR tires on it in the quest for econ. Possibly the (-) camber is a provision for squishy OE/touring tires. With stiff wall P7s maybe the negative camber is no longer necessary/desirable.

Post by **oragex** » 29 Jul 2016, 05:16

These articles explain why roads are so poor in the snow belt in the US and Canada. Add to that corrupted city council and you get potholes

http://news.nationalpost.com/toronto/to ... lt-is-made
http://www.northernontariobusiness.com/ ... rcher.aspx

Back on topic, I too played with camber settings, but haven't noticed a change in ride comfort, as long as the toe stays the same. I rather noticed a poor toe to have sensitive influence on road bumps impact on wheels. But the main culprit here are the shock/struts absorbers. Someone mentioned in a post that Sachs are rather stiff struts, designed for smooth road pavement. He installed Monroe struts and it seems the ride is significantly smoother on poor road surfaces.

Post by **JRL** » 29 Jul 2016, 13:40

I don't know how you could since castor is not adjustable in any way.
Tires make a HUGE difference
Also if your spring seats are starting to crack (but not yet broken) the strut(s) will move around a bit.
When this happens the alignment is constantly changing, foot by foot

Tonyx · Post by **Tonyx** » 29 Jul 2016, 13:46

OP: how did you reliably measure your camber??
I can't imagine most people having access to accurate measurement and adjustment to the level you implied. My interest is piqued.

Post by **mrbrian200** » 29 Jul 2016, 15:32

Suspension is nearly all new. New Sachs OE struts, new lower control arms, new upper spring seats (OE VOLVO), new upper mount/bearing (left side..the bearing on the RH is good/tight). Inner/outer tie rods are good and tight.
My method of measuring camber for experimentation is 'rough' (carpenters level with spacers so that I'm measuring against the wheel (not the tire), parked on a perfectly flat/level patch of concrete. I took a measurement before I played (the alignment shop had set both sides to -0.4. The bubble on the level confirmed both sides (-) by the same amount. Holding the level away from the wheel at the top while leaving the bottom in contact until the bubble is centered you can measure that 'gap' at the top of the wheel. With a bit of trigonometry 0.4 degrees should be measure 0.105" away from level (just shy of 1/8"), which is what I was seeing. Now adjustment is done with the front end up in the air I cut a length of 2x2 held against the tire and use the position relative to the fender/amount of change to get it to zero (yes this introduces a bit of fudge, but is good enough for experimentation), this is also when I discovered zero camber appears to be at or very close to the (+) adjustment limit.

Adjusting the camber changes the toe angles I do an initial toe set via the 'string method' then dial it in with road testing via combination of utilizing econ meter on the DIM and observed handling/behavior. Due to the nature of the suspension design on these (designed for ride quality/low noise) there's quite a bit of flare at speed...nailing the toe setting cannot be done while the car is sitting motionless/on a machine. Road testing/fine adjustment is absolutely necessary. Volvo specs indicate around 0.10" to account for this...but the amount of flare at speed will never be exactly the same from one vehicle to another even when showroom new.

I've always thought the easiest way to do this would be on some sort of dyno, but I'm not aware of any shop set up to do it that way. However aerodynamics push the car to the ground at speed (altering camber/toe from where it rests at a stop)...so...maybe not.

Did a longer mixed drive yesterday evening - 15 miles through a moderately bumpy road (not as bad as the road I traverse every day into town) with last 10 mile leg on a newly opened expressway (New US-31 Bypass into South Bend IN , poured concrete opened to traffic less than a year ago). Camber at/close to zero -- I'm keepin it-- Hands down! Had a friend with me (he's unaware that I have been messing with this, I haven't mentioned it, he's not mechanically inclined whatsoever). He had previously stated the car rode "Mercedes like", last night about half way, he broke from un-related conversation and ranted for a couple minutes "this car is amazing" and so on. Ride quality was substantially better balanced than last time he rode in the car (with - camber). He wasn't saying anything I wasn't already thinking.

Next stop is the alignment shop they'll get it even on both sides with more precision than I can and put on the new flange bolts I got. I've had the front end apart 4 or 5 times now + the alignment shop messed with it I'm seeing problems with bolt stretch. The top bolts (camber adjustment) stay put but it's to the point if I keep retorqing the bottom ones they're gonna snap...time for new bolts. But now that I've determined my preferred camber setting it'll be set and torqued with new bolts and I shouldn't be messing with it again.

Tire rack has a faq on camber and the pros and cons of different settings (positive/zero/negative). Negative camber counteracts roll during cornering but introduces bump steer on straightaways when one side, but not both, loses grip over bumps/potholes as the negative camber pushes vehicle toward of the side with reduced grip. That's definitely what I was experiencing to an objectionable level on the uneven bumpy country road.

Post by **mrbrian200** » 29 Jul 2016, 18:25

I can tell you the toe setting for peak econ is slightly different depending on uphill or downhill grade due to torque loading/bushing flex. On a 360 degree axis (rotating the inner tie rod) optimal setting for uphill or downhill is about 10-15 degrees different. If anyone like powerflex made a bushing insert for the front control arm bushing I might be tempted (or a solid bushing). I know when I take it to the shop aside from telling them to ignore the OE camber spec (set to zero or as close as they can), I'm also going to tell them to stick pretty close to my current toe setting. I already have installed inserts to the subframe bushes which did improve steering response.

Post by **mrbrian200** » 30 Jul 2016, 19:44

Highway run to Chicago for the weekend. Started with 1/4 tank. Used a hare over 1/8 tank to get to the Illinois tollway oasis where I knew I could get mobil premium (95 miles from home). Filled up and greeted to this when I restarted the car. Never seen it that high before. I was keeping a close eye on fuel/average/range as I started out with only 1/4 tank. When I got into the city it was still ticking up and had reached 29.5. All stop and go since then its come back down to 28. On long cross country runs these 2.5T FWDs will get over 700 miles on a 16 gallon fill up tank wont they! (?) That's getting into VW diesel territory. By my calculation I used about 2.5 gallons for 95 miles or right around 40mpg, maybe a tick over. Setting camber at zero has a + effect on econ for certain. And it rides better on bumpy roads.