Came a accross a write up by a Japanese MR-S owner about the ´dog bones´. Imo he is spot on and want to add that a significant part of the changed feel is because of the increased negative camber.
https://minkara.carview.co.jp/userid/392327/car/302102/2058803/parts.aspx
(https://cdn.snsimg.carview.co.jp/carlife/images/UserCarPat/2058803/p1.jpg?ct=60432e5e6902)
p.s. Boris still has some in stock. Appearantly those lowering their cars do not think it as beneficial as Toyota.
Still need to fit mine.
Quote from: shnazzle on August 18, 2020, 16:42Still need to fit mine.
It´s-a-simple.
Curious to know what you feel before - after.
Quote from: Petrus on August 18, 2020, 16:51Quote from: shnazzle on August 18, 2020, 16:42Still need to fit mine.
It´s-a-simple.
Curious to know what you feel before - after.
I'll see if I can fit them when I'm doing my brakes.
Quote from: shnazzle on August 18, 2020, 16:53Quote from: Petrus on August 18, 2020, 16:51Curious to know what you feel before - after.
I'll see if I can fit them when I'm doing my brakes.
Hint: I find them most noticeable on turn in and when the rear is on/over the limit. The former appears more planted and the latter is easier to control/correct.
Are these only to fit the Sportivo shocks or would stock be fine?
You can fit them anyhow.
I have them with stock shocks/springs.
My take on it is that with the softer stock set up, the effect is the same because the geometric change is. The difference just less notable because the car has more compliance than with a firmer suspension set up.
Think I will just fit the adjustable camber bolts when I need to sort out the rear camber.
Quote from: m1tch on August 19, 2020, 09:46Think I will just fit the adjustable camber bolts when I need to sort out the rear camber.
That sorts out camber but not the change in roll center.
That's what these are for right?
Quote from: shnazzle on August 19, 2020, 09:56Quote from: m1tch on August 19, 2020, 09:46Think I will just fit the adjustable camber bolts when I need to sort out the rear camber.
That sorts out camber but not the change in roll center.
That's what these are for right?
It does both. Toyota also refers to both although they call them spacers to change the roll centre. It thus would séém that this is the primary aim but that they also give more negative camber is obvious.
I have camber bolts front and rear ánd the dog bones.
At the rear the bolts did not give me the negative camber I wanted and fitting top ones too... well no; they are after all weaker bolts.
The dog bones give me the changes Toyota thought necessary and in combination with the camber bolts the range of adjustment I want.
I can not think of an issue, reason not to fit them. I mean, Toyota thought them necessary for improved rear traction with no caution about use whatsoever.
But, it was only in combination with the lowered Sportivo springs right? So, it's to compensate for the lowering of the car.
Quote from: shnazzle on August 19, 2020, 11:50But, it was only in combination with the lowered Sportivo springs right? So, it's to compensate for the lowering of the car.
I don´t think so as it does NÓT put the roll centre back. I have extensively explained that earlier in a thread about it´s geometric effect.
It is about roll centre tuning; the rear vs the front. Additionally it gives negative camber. The effect of it is as such independent of lowering the car.
Akin to fitting different shocks and springs without changing the sway bars or vv. Or akin to shocks, arb with/without extra chassis bracing.
It all does what it does seperately and in combination.
The thing with the ´dog bones´ is that they are invisible so hard to market, more so because they are a hard sell because poorly understood and lastly they are rather cheap so not much of a money maker. Hence it is the only bit in the complete kit not for sale seperately, adding a selling point for the complete kit.
Quote from: Petrus on August 19, 2020, 12:13Quote from: shnazzle on August 19, 2020, 11:50But, it was only in combination with the lowered Sportivo springs right? So, it's to compensate for the lowering of the car.
I don´t think so as it does NÓT put the roll centre back. I have extensively explained that earlier in a thread about it´s geometric effect.
It is about roll centre tuning; the rear vs the front. Additionally it gives negative camber. The effect of it is as such independent of lowering the car.
Akin to fitting different shocks and springs without changing the sway bars or vv. Or akin to shocks, arb with/without extra chassis bracing.
It all does what it does seperately and in combination.
The thing with the ´dog bones´ is that they are invisible so hard to market, more so because they are a hard sell because poorly understood and lastly they are rather cheap so not much of a money maker. Hence it is the only bit in the complete kit not for sale seperately, adding a selling point for the complete kit.
I forgot man :D Can't keep track of all the posts on here hehe
Quote from: shnazzle on August 19, 2020, 13:16I forgot man :D Can't keep track of all the posts on here hehe
Never mind; the proof of the puddin´ is in the eatin´: Am curious wether you will notice anything.
If you have an on-Sunday-morning-empty industrial estate or such near, that would be the place to do a before and after, sliding the car about near/on/over the limit of rubber adhesion. In the wet it may be easier even as the speeds are so much lower but the car and how it responds basically the same.
Not fitted mine yet forgot when I was changing the subframe! Might have a go next weekend when swapping the sump
Quote from: Mark A on August 23, 2020, 17:45Not fitted mine yet forgot when I was changing the subframe! Might have a go next weekend when swapping the sump
Again; curious about whether you´ll notice anything.
Aha! I understand what they do now thank you for the write up! Ill order some from Boris.
Cheers
Sorry for the slight thread revival, might look to get some of these and fit them as I am running lower - wonder if a wide M12 washer would work instead, think they are only 3mm thick?
Quote from: m1tch on March 9, 2021, 11:13Sorry for the slight thread revival, might look to get some of these and fit them as I am running lower - wonder if a wide M12 washer would work instead, think they are only 3mm thick?
3.3 mm. I thought and yes geometrically it would work too.
Just be more critical to tighten it down real good as the friction area between the subchassis and chassis will be smaller.
But think of the beautiful works of art you'd be missing out on ;)
Quote from: Snelbaard on March 9, 2021, 12:32But think of the beautiful works of art you'd be missing out on ;)
I am still pondering if I should buy them as with a lowered car the angle of the lower arms are flatter so adding a spacer between the body and subframe seems a bit counter intuitive as it wouldn't correct angle but make it an even flatter angle.
Yeah I going to defer you to Petrus for a detailed explanation of the spacer's functionality. He's written a few essays on them.
Quote from: Snelbaard on March 9, 2021, 13:55Yeah I going to defer you to Petrus for a detailed explanation of the spacer's functionality. He's written a few essays on them.
LOL!
Quote from: m1tch on March 9, 2021, 13:42I am still pondering if I should buy them as with a lowered car the angle of the lower arms are flatter so adding a spacer between the body and subframe seems a bit counter intuitive as it wouldn't correct angle but make it an even flatter angle.
They are not about restoring the roll centre but about roll centre bálance.
If you lower the car you lower the roll centres of the suspension.
The front RC lowers more than the rear.
The TRD spacers slightly lower the rear RC so it matches the front better, restoring RC balance (closer) to OEM set up.
Quote from: Petrus on March 9, 2021, 15:42Quote from: m1tch on March 9, 2021, 13:42I am still pondering if I should buy them as with a lowered car the angle of the lower arms are flatter so adding a spacer between the body and subframe seems a bit counter intuitive as it wouldn't correct angle but make it an even flatter angle.
They are not about restoring the roll centre but about roll centre bálance.
If you lower the car you lower the roll centres of the suspension.
The front RC lowers more than the rear.
The TRD spacers slightly lower the rear RC so it matches the front better, restoring RC balance (closer) to OEM set up.
Ah, fair enough, I know you can get RCA for the front from Hardrace, I guess it would also depend on how much each end of the car is lowered by if changing the rake angle as well.
Correcting the front RC still leaves you with a mistmatch; most like larger one, as there is no available solution for the rear.
The TRD spacers were part of the Sportivo kit which lowers the car some 25mm front, 20 rear.