GR Yaris Geo fast road help and track set up

[Spirited]

Hey everyone,

I have bought 90105-17013 bolt. I plan to mount them in order to reach - 2.2 ° / -2.3° camber front.

From what I understood, I can have - 2° rear with stock bolts.

That would allow me to have - 2.3° front and -2° rear which seems perfect for me and my "fast road" use. I don't want too agressive camber that would destroy the inner line of my tyres.

However I'm a bit lost when it comes to toe. I am tempted to keep stock toe front/rear as I find the entry balance quite good. Is it a mistake given the camber change ? Should I go for close to neutral front and some toe in rear ? I like a bit of oversteer during entry as I'm used to FWD cars but I don't want the yaris to try to kill me during fast corner entry either.

What would be the recommandation ? Stock suspensions, standard PS4S. Thanks !

No expert here; so, just sharing some thoughts rather than recommendations.

I am under the impression that rear camber is not adjustable with stock bolts. You may already have - 2 deg camber there by coincidence, in which case, great for you. But you may as well have a different setting and also significantly different settings on each side. There are aftermarket bolts that you can use to bring the rear camber at - 2 deg.

I can't see a problem with - 2.3° front and -2° rear, especially if you're coming from FWD cars.

Regarding toe:

- front is more of a personal preference rather than safety matter, as understand it. I can't see anything wrong with sticking to stock values or specifically middle of that range, even with your altered camber. However, I recall that stock values are a wide range. (Also, I have opted for toe out, as I like the eagerness this offers and take every opportunity to minimise understeer.) For @Onehp 's usefully simplifying view of the effects of getting from slight toe-in towards neutral, see https://www.gr-yaris.co.uk/posts/43405/

- rear is a matter of preference, but also a safety consideration. If, as you mention, you don't want the car to try to kill you, you just stick to well within stock values, install a harder rear trailing arm bush and still be mindful crests, lift-off oversteer, etc.

 

[Yaris San]

Front is 0°08' or 0.14°. In this case, I think I have to correct myself, then the front toe is pretty much what Toyota specifies.

At the front, I followed Toyota's instructions for the toe. Let's see on Friday what the current values are.

The last few days have been nice here in my neighbourhood and I was able to do a few laps with the GR on the road. I can already say, regardless of the suspension settings, that the Yokohama A052 opens a new chapter in terms of grip, no comparison with the Michelin or Goodyear. Where the car used to slide slightly and the tyres used to squeal, now there is just ungodly grip. Unbelievable, confirms once again that the most important tuning on a car is the tyres. A speed in bends that is borderline or let's call it sick on public roads. Summer can come.

Front

you're still going to kill the inside tread first on either of the front unloaded tyres as it 'scrapes' round tight corners, only way is to increase caster

having a good understanding how caster works, how it induces dynamic camber and stands the wheel more upright the more you turn it then you can also see how low caster angle allows an unloaded wheel to fall over and 'drag' killing the inside tread on tight corners

 

[Yohz78]

No expert here; so, just sharing some thoughts rather than recommendations.

I am under the impression that rear camber is not adjustable with stock bolts. You may already have - 2 deg camber there by coincidence, in which case, great for you. But you may as well have a different setting and also significantly different settings on each side. There are aftermarket bolts that you can use to bring the rear camber at - 2 deg.

I can't see a problem with - 2.3° front and -2° rear, especially if you're coming from FWD cars.

Regarding toe:

- front is more of a personal preference rather than safety matter, as understand it. I can't see anything wrong with sticking to stock values or specifically middle of that range, even with your altered camber. However, I recall that stock values are a wide range. (Also, I have opted for toe out, as I like the eagerness this offers and take every opportunity to minimise understeer.) For @Onehp 's usefully simplifying view of the effects of getting from slight toe-in towards neutral, see https://www.gr-yaris.co.uk/posts/43405/

- rear is a matter of preference, but also a safety consideration. If, as you mention, you don't want the car to try to kill you, you just stick to well within stock values, install a harder rear trailing arm bush and still be mindful crests, lift-off oversteer, etc.

Hey,

Thanks for your answer. I thought that rear camber was pretty adjustable as stock but I guess I was mistaken.

Is it possible to use some OEM toyota's bolt or I have to settle for some powerflex bolt for instance ?

I'll keep stock toe value. I like the car as it is, it just lack front camber to me but as I wan't to keep the car balanced, I have to get a close rear camber

 

[Spirited]

Hey,

Thanks for your answer. I thought that rear camber was pretty adjustable as stock but I guess I was mistaken.

Is it possible to use some OEM toyota's bolt or I have to settle for some powerflex bolt for instance ?

I'll keep stock toe value. I like the car as it is, it just lack front camber to me but as I wan't to keep the car balanced, I have to get a close rear camber

I'm under the impression that rear camber is not adjustable as stock. Powerflex or similar is the cheapest solution I could find.

A good starting point may be to establish what stock settings you currently have exactly. See how fortunate @Sam is with rear stock camber on his: https://www.gr-zoo.com/threads/caster-query.6474/post-99311

Some places offer an alignment check & report for free or very low price. If I had got a report with @Sam 's rear camber, I almost certainly would not touch that camber, as it's near perfect for me & almost everyone else. Unfortunately, I'm not sure many of our cars come like that.

I fully agree with you on keeping a good front-rear camber balance. If you' re balance-conscious and don't want rear antics, definitely consider a harder rear trailing arm bush of some kind: https://www.gr-zoo.com/threads/rta-rear-trailing-arm-bushing.6692/post-102458

 

[Heliomalt]

@Yaris San
That surprises me a little, because I use the values specified by Toyota and yet you say that the tyres still wear more on the inside than on the outside.

Changing the caster is not possible with the original suspension and without additional parts and there is nothing in Switzerland that is allowed, as you will need papers for pretty much everything in 2025, it's not like it used to be.

I've read in a few places here and on other forums that some owners are running 0° to 2' max with even tyre wear. However, I don't know where and how they drive and I have no experience with the Yokohama so far. With the two UHP tyres, wear was clearly visible on the inside with too much toe as well as with the original settings.

I'm still undecided whether I'll put the original bolts back in tomorrow and run the factory setup with the A052 or set the front camber to 2.5° and toe 0°. I spoke to someone today who has 16000km on the car and is still driving with the Michelins and hasn't changed anything, not even readjusted. Kind of crazy...

 

[CSL]

hi guys quick question, whats the maximum camber you can get on the rear stock camber bolts that came with the car ?
also what are the part numbers for the REAR camber bolts from Toyota ?

thank you in advance.

 

[Bronson]

Pretty certain it’s -2 on the stock bolt, -2.5 with the Powerflex bolts. Not sure about the Toyota ones.

 

[Michael Knight]

Pretty certain it’s -2 on the stock bolt, -2.5 with the Powerflex bolts. Not sure about the Toyota ones.

I'm at 2.75' (or 45 minutes) with powerflex for front axle.

 

[lee1563]

On or around 2.8 with Toyota bolts on the front.

 

[Michael Knight]

Anyone getting any temps to rear tyres with GR?
Was yesterday at track session and was struggling to get any heat to rear tyres.
they peaked at 24'C. wery difficult to get rears working.

I'm with stock suspension and sways so maybe it is what it is. Maybe I'll test the extra front camber as well. three sounds like a good figure.

 

[Orion]

Anyone getting any temps to rear tyres with GR?
Was yesterday at track session and was struggling to get any heat to rear tyres.
they peaked at 24'C. wery difficult to get rears working.

I'm with stock suspension and sways so maybe it is what it is. Maybe I'll test the extra front camber as well. three sounds like a good figure.

also on stock suspension, camber -3/-2.5, stock tire sizes
I can only put some head in the rears if I drastically lower their pressure. My hot pressures are around 2.7bar front and ~ 2.3 rear, ESP fully off, sport mode (I need the high front pressure as my track is really abrasive -- anything lower destroys the outter shoulders)

Even this way, I'll get the rears to ~75% of the front temps... e.g. fronts up to 70-80degC, while the rears will only get to 50-60degC

 

[Michael Knight]

also on stock suspension, camber -3/-2.5, stock tire sizes
I can only put some head in the rears if I drastically lower their pressure. My hot pressures are around 2.7bar front and ~ 2.3 rear, ESP fully off, sport mode (I need the high front pressure as my track is really abrasive -- anything lower destroys the outter shoulders)

Even this way, I'll get the rears to ~75% of the front temps... e.g. fronts up to 70-80degC, while the rears will only get to 50-60degC

That sounds much better.

 

[GottGry]

I have a lot of camber front and rear. I don't know the temperatures, but say not far from hot in the front and warm in the rear. I try to aim for hot pressures 2.1-2.2 in front and 2.3-2.4 in the rear. A052's.

 

[Orion]

I have a lot of camber front and rear. I don't know the temperatures, but say not far from hot in the front and warm in the rear. I try to aim for hot pressures 2.1-2.2 in front and 2.3-2.4 in the rear. A052's.

what tire size are you running? My assumption is 2.1-2.2bar front on stock sizes would disintegrate your outter shoulders on any grippier surface?

 

[GottGry]

what tire size are you running? My assumption is 2.1-2.2bar front on stock sizes would disintegrate your outter shoulders on any grippier surface?

255/40x17 on 17x9"
my front doesn't wear as much as the rears do.

 

[sixtentouge]

This was a super long, super interesting read. Thanks to all for all of the input. My car is 100% fast road, tight winding. Not driving anywhere near 100%. Through recommendations from a GRY development engineer for winding, and simple change-and-see adjustments, this is how my car looks, just in case people are still looking for stock-ish fast-road setup examples.

Lowering the car about 2cm on 4.08 and 4.29 kg/mm springs, the stock front camber changed to 2.0° and the rear is 2.1°. Front toe total 1.5mm out, rear 0mm. Everything else is stock RZHP. The spring set with stock dampers was development engineer recommended.

Wheels are 18x8.5 +35. I tried the Nankang CR-S tires, but they were just too much for the road. Massive grip, but the car feels like you're just steering it around corners, and all the stock bushings just aren't up to the task. The PS4S, while less grip, make the car "feel" much better. I've also run the stock wheels and PS4S with 15mm Digicam spacers, bringing the offset to +30. IMO, the reduced offset greatly improves how the car feels and responds. The stock size, but +30 offset was development engineer recommended. GR Corolla wheels are 18x8.5 +30 (making that car 45mm wider), and I'd really like to try a set of those.

90% of the time, I stay in "normal" 60:40, and corner exit acceleration feels very neutral. If with friends and getting after it a bit, "track" 50:50 does better.

 

[Michael Knight]

increased offset makes the steering pump work harder + increased bump steer etc, reduced wheel motion ratio (spring stiffness) etc.
you get similar improvement in feel and wheel centering from increasing negative caster.

 

[sixtentouge]

increased offset makes the steering pump work harder + increased bump steer etc, reduced wheel motion ratio (spring stiffness) etc.
you get similar improvement in feel and wheel centering from increasing negative caster.

The +30 is based on a face-to-face sit down with a GR Yaris development engineer during a customized GR Selections driving event, for fast-winding.

Literally, "Change the wheels to a +30, and increase the spring rate to these springs. If you can get a set of GR Corolla wheels, do that."

It transformed how the car feels at 60% on tight winding mountain roads.

 

[micsub]

Just a 2c input that most of you probably noticed while playing with the rear alignment OEM settings bolts : When one adjusts rear toe, (and it's a real PITA it is so damn sensitive !) rear camber is modified at the same time. Before, I had close to -2° camber with 5' toe IN each side and when adjusting toe to zero, (with a lot of patience !) rear camber became -2°15' L and -2°20' R.

 

[Michael Knight]

for the reference, rally2 car can use springs rates of

Setup	Front (N/mm)	Rear (N/mm)
Gravel	20.1-35.8	20.1-35.8
Tarmac	35-71.8	35-71.8