Rough and gravel road suspension setup
 

I've been doing some research but I'm having a hard time finding an answer. I love my 17 brz all around(stock everything), but where I live the roads are concrete and pretty rough, not so many potholes, but more cross-road lines and frost heaves from winter, also I live near alot of gravel twisty roads(potholes) I'd like to drive "spiritedly" on. So The ride is Rough for me. I know decreasing the tire pressure will help, but would a taller sidewall help as well? And Would raising the car an inch help? I dont mind sacrificing a bit of cornering ability, I just want to smooth it out a bit. Any advice appreciated. Thanks:iono:

I wouldn't go straight to a taller tire, but rather same overall tire diameter on a 16" wheel to get more sidewall. 225-50-16 should fit the bill, and there's some nifty wheels that are rally style in that size that don't break the bank:

http://www.ft86club.com/forums/showthread.php?t=57975
(If you have the Performance Pack with the big brakes fitting smaller wheels might be problematic)

There's a couple springs/coilovers that target rally style, but nobody to my knowledge is running them in America and the guys running their 86's in rally competitions are mostly custom setups or near stock. Quick googling comes up with MCA and Ohlins providing setups for some people, but that's in the $3k+ range.
http://www.ft86club.com/forums/showthread.php?t=57564
http://www.ft86club.com/forums/showthread.php?t=79713

I wouldn't bother raising it up with spacers as it seems the primary concern is ride quality not ground clearance, you might get a minor improvement, but I'd focus on the suspension side of thing if you're going to be disassembling the suspension.

Maybe a softer coilover setup like off the shelf Ohlins or Bilstein B14's with the height maxed out might get you what you're looking for. I know the Ohlins can match stock height, there was a post here by works about it, and the more I think about it the soft springs and reputation for cushy valving might be a great match and without the top hats they don't really break the bank.
http://www.ft86club.com/forums/showthread.php?p=2749417

Thank you for the informative reply strat61caster, I cant afford the ohlins coilovers right now, after putting 5k down on the car, so I'll probably go with the 16's. But just wondering, could'nt I go to a slightly taller tire on my factory 17's without rubbing on the fenderwells? Thanks. (yes I'm clueless on tires and suspension).

Also one other off topic question. The other day I went to do a burnout in 1st and my shifter shook left to right violently, and the rear end was jumping, not spinning like a normal burnout, like I could'nt even keep a grip on the shift knob. Is upgrading the transmission mount the cure for this? Thanks.

And those rally wheels are pretty cool. Cheap too!

Buy a truck.

Already got one! :thumbup:

You could do a 225/50-17, and people have. It looks really meaty. The downside is that you've increased the rolling circumference and that will throw off your speedo and mileage counter. There are a few rally-oriented cars around here; dig around a bit and see what they've done. The inexpensive way is 3/4" or 1" spacers on top of the struts. The expensive and more functional way is longer travel coilovers. One problem with raising is dealing with the positive camber you've caused.

For the transmission shake, look at a transmission bushing insert and a rear shifter bushing. Both are inexpensive and easy to install. For the rear end hop, look at whiteline diff carrier bushings. The diff flops around pretty severely on the OEM bushings. The downside is a little more gear whine at low speeds. But that's ok, because racecar.

Rally thread:
http://www.ft86club.com/forums/showthread.php?t=105692

Yes you could go taller, there is lots of clearance to the fenders in this car, but in the interest of keeping things budget friendly you have a decent set of tires that should last tens of thousands of miles currently, it'd be kind of a shame to throw them away as they're about $180/each to replace (there are much cheaper options available of course).

You'll likely decrease fuel economy, increase weight (making the suspension work a little harder) and have to adjust for a speedometer that's no longer accurate due to the taller tire which will also slow your acceleration. But yes, you'll get taller sidewall and theoretically more 'cushion' to your ride.

The burnout description sounds totally normal, the shift lever is directly attached to the drivetrain, many modern cars have cable shifters (or automatics not attached to anything at all) which hide the drivetrain movement from the driver.

I have no experience with the transmission mount but that would be a logical conclusion to make. For me installing the whiteline subframe bushings helped the rear end (and as such the gear lever) feel more planted, the differential bushings not so much, but maybe I'm crazy, but that does lead to a bit stiffer ride and NVH, not much, but counterproductive to what you came in here with.

So, I'm going to get the transmission mount 4 sure, And I guess I'll go with the 16" wheel setup, with a rally car looking theme, after these factory tires are toast. I'll be drifting the backroads in no time!
Because Rally/Racecar? :cheers: Thanks again guys!

You have 4.9 in of ground clearance already. Buy a set of mud flaps for a FRS GT86 from your Toyota dealer and you'll be good to go. 2017 suspension will be fine for rough roads. Don't lower tire pressures though, not the solution.

A set of 205/55 x 16 tires on 16 in Impreza rims would work very well. Standard fitment for the BRZ in some markets like Australia.

Every BRZ should fit the transmission mount insert. Slight increase in gear noise idle is a very small price to pay for stability of the shifter.

I'd consider fitting a set of MCA traction brackets to reduce anti squat forces from the rear. That improves traction and ride.

I'd probably limit options of lifting by changes to suspension via coilovers and/or spacers within 10-20mm. I guess that in similar way if one lowers one >1", then if one rises by >1", one might also need extra parts, like roll center correction/diff lowerer and alikes ..
If you still absolutely need even more, then net that extra with bigger tires (not wheels).
I'm not sure you need extra ground clearance so much as shock travel.
BTW, worth thinking in investment in extra engine protection pan.

I'd try those mentioned TRD rally coilovers (probably will net you not just +10mm ground clearance, but also if there really is any real rallyiness in them, then maybe extra strength & extra travel too. About the only facts that kept me from getting those, i've yet to see any review of them from some owner and their suspiciously cheap price).

Or - KW/RCE ones + extra lift spacer of .. eg. 20mm. KW V1/V3 coilovers have minimum lowering below stock (thus spacers), but they have longer travel then stock.

No comments on GC, as i have no experience with those.

Better not to get generic aftermarket shocks that in most cases target lowering crowd, tarmac track racing and so on. Limited travel, even lower height, stiff springs.

"Real rally coilovers"? Forget about those. 1) they will cost $7-15K, 2) depending on abuse may need overhaul in 1-2K miles.

It's important to remember the difference between ground clearance and suspension travel. Changing the ride height does not affect suspension travel nor does it affect ride quality. Only changing the spring rate and damper rates to match will change ride quality. Changing the spring length (with or without changing the spring rate) changes the suspension travel. Changing spring length will usually require fitting longer travel dampers. You never want to do that to a BRZ.

Gravel roads are not off road. There are two hazards presented to the chassis by gravel roads, both due to maintenance interval. Where the gravel road forms part of the highway system as it does out here, maintenance is quite good.

Potholes are the biggies for ground clearance issues and they have to be avoided by cars regardless of suspension travel. Deep ones require significant suspension travel and very strong tires. Only pickups or real off-road suspension systems can ride potholes safely.

The most common issue is washboard compliance. Since the BRZ has a relatively high spring rate for its weight and good shocks, particularly 2017, it will actually ride washboard better than a more softly sprung car provided you drive fast enough to hit the correct harmonic.

Just as the more expert ski runs have deeper and steeper moguls so gravel roads develop washboard that coincides with the spring and damper rates of the most common vehicle using that road: the standard and unladen American style half ton truck. The washboard frequency matches the rear spring rates of those vehicles and so most users prefer that vehicle not realizing the ride they think is so good is actually the natural result of the rear drive wheels bouncing along at the communities' effective speed limit (not the posted limit, out here nobody drives that slowly).

Most people in softly sprung SUV or passenger cars drive too fast to match the washboard pattern. Since the spring rate of these vehicles is lower they need to go slower to get in sync with the washboard. Go as fast as the average unladen pickup in a car and you get the wallows. You can even get airborne if the washboard is bad enough.

The good news is you need to drive even faster on washboard in a BRZ....

One more aspect of this rough road topic. It should be remembered that these cars are not effete little Euro coupes. They are immensely strong, tough little street fighters. I drive mine on the street fairly aggressively and year round in all weathers. It's been on a poorly maintained gravel road. It only has the originally supplied squeaks clicks and rattles it came with from the factory (and the 2017 has most of these welded up or beefed up and fixed). Warranty service has been literally zero apart from the officially authorized attempt to lubricate the parcel shelf spot welds which I don't count as a "repair".

From an engineers perspective these cars are just Subaru Impreza's with two inches cut out of the floorpan and short overhangs. A two door Impreza Coupe with all of that car's endearing robust character. Perfect for driving on a gravel road in the real world.

These cars are so strong that they provide top notch occupant protection on a collision or rollover. You can take one off the showroom floor and thrash it around a track or time attack course all day and then drive it home and to work the next day. Nothing will have broken or fallen off.

These cars are built to take it.

This is great advice. All of it. Seeing as I live in the "country" and I'm never plan on living in a "city" again. I am surely building my BRZ the Rally theme. Lowering the car "2inches" and having crazy camber and rims is not my thing. I want performance first, looks second. I have nobody to impress but myself, so performance is my goal.
And Thank you for all the great advice... (alot to think about) :)

Thought these cars were no good on the track? Didn't you say that a few days ago?

No, he said on public streets.

BTW, i've been my share on gravel roads on completely stock suspension. It's lot of fun, as much as ice/snow roads driving. Few hints with using stock heigh/stock suspension:
- road pavement doesn't mean how good road can be. You can go fast on good gravel road, if it's not full of big stones/potholes and such.
- for worse roads limit never go too fast driving them first time. When you've been driven there few times, you should learn, where the biggest roadholes and such are, drop speed as needed. Normally driving at normal speeds it should not be of impossible challenge, heck, at least front of wrx of my colleague is even lower then my gt86, and he does lot of rallying (has proper CF engine/bumper protection pan though, so bit less scare of hard landings)
- visibility. 3 times highlighted. Gravel roads are often in country, with trees/houses/whatever blocking view behind low radius turns. Always leave big enough safety margin when you don't know what's ahead. There always can be some local driving in opposite direction, or some pedestrian in middle of road or some wildlife animal and so on. Never go too fast to not be able to stop or maneuver around unexpected. Leave excessive speed for visible far ahead stages or for specialised rally roads/stages with blocked off traffic by race officials and so on to lessen chance of unexpected problems / push only in controlled situation. With seeing far ahead you'll also be able to use whole road width.
- be careful with overestimating own skills. Imho even better is to drive fast where environment is controllable and mistakes are less costly - i.e. on track. There, if you loose control, in many cases you just slide outside track on grass till stop, or other track day enthusiasts will see you far ahead to be able to stop in time, one direction traffic. Less hitting kerb and damaging suspension, less damaging body/bumpers (which might get rather costly even for minor crashes. For example - in pre late-2014 even refills after leak from damaged AC heat exchanger may get very costly (guess, how i found out :)). It's not always just changing bumper and paying for it's repainting. And yes, big flashy rally jumps or going straight over ditch/cutting corners are not for our stock suspension. I'd even wouldn't turn off VSC off when not on track, somewhere where mistakes are less costly. Not 'because racecar', but 'because paid for repairs', when overestimated my still lacking skills too much/too soon.

They are slower than they could be. The 2017 fixes all that. By changing the front to rear spring rates they have pushed the roll resistance balance forward onto the front axle. They have also improved the quality of the damping and changed the damping rates.

I have yet to drive a 2017 but all the reports are favourable. Since my car is setup almost exactly the same as the current 2017 and now handles perfectly I expect the 2017 is as good as everyone says it is.

I hope that is a helpful answer to your question.

Oh, one further thing. The factory has not changed the rear suspension geometry correctly. It will be the cost that is stopping them. Fortunately the Australians have a fix. Australians are big fans of Subarus and racing, they know what they're about.

No difference. A car handles the same on the streets as it does on the track.

In the dry the stock pre 2017 BRZ on stock tires lacks rear axle grip. This shows up particularly in low grip situations, such as wet or snow. This is no surprise. Roll stiffness needs to be reduced if road grip is reduced.

This is a deliberate design choice by Subaru. They wanted a low powered car that is easy to drift. It is. That is by definition a slow car.

It is slower than some and faster than many. Does not mean it is defined as slow.

If you are driving the same way on the track as the road you are doing one of them all wrong.

&... done. Bye bye dart17. See you in 2wks

Sorry about my part there ichi. These guys are just too much to bear in silence.

The car handles the same on the street as it does on the track. You might have noticed today that racing cars can race on a closed street circuit at say Monaco or Valencia or Singapore. Street cars can race on a track. If you think your car will handle differently just because you take it onto a track you are in for a big surprise.

Driving techniques are exactly the same if driving at the limit whether on track or street. The difference is only that you cannot feasibly drive most modern performance cars at the limit on the street unless it is closed for that purpose.

Driving safely on the street (at any speed) requires orders of magnitude more skill than driving on a track. Ask any racing driver.

This was my point right there ^.
If you are driving at the limit on the street you are driving wrong.
If you are not driving at the limit on the track you are also doing it wrong.
Many of the techniques used on the track should be reserved for the track.

The stock BRZ is just not a performance car by any stretch of the imagination. Also, you can have no idea whether the chassis limits can be reached legally on the street in a BRZ because you never switch off the stability or traction controls.

It doesn't need to be a performance car to exceed what is safe or legal on the streets.
Because I said the traction control can save you In the snow does not mean for one second I don't turn them off. You make a lot of presumptions with nothing to back up your statements.

Why do you ever switch them off?

Traction control cannot save you in low grip situations. Neither can stability control which is what I think you are actually referring to.

Traction control just prevents wheelspin from the drive wheels, and winter conditions are one situation where switching it off can be helpful, in loose snow for example.

Stability control reduces the tendency of the chassis to oversteer, primarily. It isn't much use if the chassis is understeering, though it will try to correct that too.

If you are understeering, you're doing it very wrong.

As for the nannies (TC, VSC, ABS), their objective is to keep the car straight. If you are driving right, they won't really interfere until you start hitting the limit of grip. Then they become more of a nuisance. If I can take a corner at 50 without tripping them, but you start tripping them at 35...well you know where I'm going with this. Or maybe you don't. (Now to continue losing brain cells.)

A car that steers from the front axle must understeer to initiate any turn. After that, whether it continues to do so or not depends on a number of factors. Every road car I've ever driven, including Porsche 911, understeer.

Traction control is to prevent wheelspin. It has nothing to do with keeping the car straight.

Stability control is intended to keep the car straight.

Neither one improves tire grip.

ABS has nothing to do with keeping the car straight either although it makes it very easy for the driver to do. EBD is intended to keep the car straight under braking. All modern ABS also has EBD. Older versions of ABS did not.

VSC is the same as stability control but the control parameters are extendeded to allow a little instability before stepping in.

Subaru's traction control and stability control systems are not very good. They step in far too early. 2017 versions are much improved.

Driving the BRZ as I would any other car results in the traction and stability control intervening. That's how I know they aren't very good.

With both switched off it is ridiculously easy to step the tail out on these cars, again comparing the BRZ to every other car I've ever driven, including some with 600+ horsepower.

You keep saying how much better the 2017s are at everything yet you also say you have never driven one. How do you know they are so much better?


Were all the cars you have driven set up exactly the same as the BRZ? If not then you can not say the nannies are good nor bad based upon a comparison between different vehicles.

I rarely get the nannies to kick in while driving around. Only time it happens is in the winter and when driving in sub 20*C, wet weather with my summer tires (thanks 200TW). I must be doing it entirely wrong.

Well that is what you get for driving this car in the winter since we all know that "real" drivers all say it is impossible to do.

My head hurts.

Since the OP was banned, but I found this question interesting, postin anyhow. There's been quite a bit of development work to prep these cars for off road fun. From the videos below I search for the owner and race team names and you'll eventually find specs from Street to Rallycross to Rally.

[ame="https://www.youtube.com/watch?v=mrou6X0p_Qs"]Will Orders at the 2013 Nameless Rally in the Nameless Performance GT-86. - YouTube[/ame]

[ame="https://www.youtube.com/watch?v=oyjXlt--JhQ"]FR-S Rallycross run 4 - YouTube[/ame]

[ame="https://www.youtube.com/watch?v=5YvuHbf0cIk"]Targa Newfoundland in a Scion FR-S - Living The Dream - YouTube[/ame]



I was pretty quickly able to find a company called Flatout Suspension that has a coilover set @$1800 for this purpose. I'm sure they'd be willing to give you wheel, tire and suspension specs & assistance if you end up going that direction.

https://www.flatoutsuspension.com/pr...ant=3846737796

https://cdn.shopify.com/s/files/1/07...g?v=1496076821

The journalists who have driven them all say the same thing. Besides, in effect, I do drive a 2017 and it's much better than it was.

I can and do assert that the original traction and stability control fitted to my BRZ are pretty bad. They are obviously intended for unskilled drivers. If you push the chassis at all hard you will experience the stability control taking over.

Not wrong exactly but you did waste your money.

Ah so just parroting others and stating as if first hand knowledge then.
"Better" for your likes maybe, that does not make it "better" overall. You changed the suspension to suit you and that is fine but it does not mean the old one is not preferred by other people.
The traction and stability controls are all made for unskilled rivers or even skilled drivers driving under normal condition. That is why they can be toned down by a simple push of a button or turned right off by the pedal dance. No doubt though if you turned them off and curbed the car you would find some way that it was the chassis' fault not yours.

No, better objectively. By no standard is the earlier car as good as the 2017 version. If anyone actually prefers the older suspension they just don't understand how suspension is supposed to work. I do.

Even Subaru knows they made a mistake with the first version. The FRS was the worst with its harder rear springs, the GT86 was a bit better and the BRZ best but not until 2017 did they fix the serious deficiency in their choice of rear spring rate. I realized this within a few weeks of buying mine. It took nearly four years for anyone to build the correct rate rear springs to fix the problem. Most buyers had to resort to lowering springs or fitting stiffer springs front and rear to get the chassis to work properly, both of which solutions were incorrect.

LOL. Do explain how I wasted my money. Cant wait to hear what the guy who thinks stock suspension is best has to say.

Yep. They slowly dumbed down the suspension to hit what the average driver would want no doubt about that. Probably just the beginning of turning the car into a Genesis coupe clone. Many buyers (on here) would change the suspension even if it was the best ever made. The 17s will get changed at the same rate as the prior years will.

I'm suggesting most buyers don't give a damn. That is, they bought the car as is to drive as is.

Do people have to recite Pascal's law to use the brakes?
Once again I'm suggesting most people don't know and don't care.
80 percent of BMW 1-Series owners think their car is front-wheel drive

You don't seem to appreciate what "compromise" means.