GR86 GR86 - Brake Upgrade Guide

[Godspeed]

Hi
I was in contact with Duncan yesterday while the kit was being fitted , so fully up to speed with whats going on , TBH , I have no idea why it's rubbing !
We have sold plenty of these kit with no one coming back and saying it's rubbing , Duncan has already fitted these kits to other cars , with no rubbing , so we are both at a loss.
Just to dispel any of the things already said , no our bells are not thinner making the wheels go in further , in fact the bell is 0.7mm thicker , I like to have at least 7.5mm wall thickness for strength , i'd rather my kits over engineered and strong rather than the other way round , we do take them thinner on race and rally cars to save a tiny bit of weight , where saving weight is a priority , so as the wheels are out 0.7mm further than standard , it will be interesting to see if a spacer makes it worse.

I have just bought an M2 , and i'm having spacers delivered today as I want to bring the wheels out to fill the arch , and on them the tyres catch on the front of the liner , but that is with 15mm spacers , i'm wondering if the 0.7mm is creating the same affect on your car , with the wider than standard tyres , and if it does , it must have just been on the limit of catching with the standard brakes.

If duncan finds it an issue with the bell being 0.7mm thicker , I can make you a pair of bells with exactly the same thickness as the standard discs and see if it cures it , i'd be amazed if that was the issue , but if it is , it's an easy fix
Cheers Ian

 

[Sonic]

Thanks @Godspeed I’d like to get to the bottom of it as my other concern is for when I come to put my Bola alloys back on next summer: these are a slightly wider rim at 8” (rather than 7.5”) with a modest offset of 42 (down from 48) and are again fitted with performance 225 tyres.

 

[Godspeed]

To save any waiting , i'm in work today , i'll make a pair of bells with exactly the same thickness as a standard disc , get them to plating on Monday , should be done by Wednesday , i'll ship them to duncan to swap when he has your car in to have a look , and the wheel will be in exactly the same place as it was before , 0.7mm further in , if it never rubbed before , then it shouldn't rub with these on
Cheers Ian

 

[ZN8]

Can't ask for better service than that @Sonic

Seems odd though, 0.7mm is negligible, it shouldn't make a blind bit of difference, especially when people are tucking 9.5j wheels on these cars and removing 15-25mm clearance on the inside. Doesn't make any sense.

 

[Alistair31]

I was in contact with Duncan yesterday while the kit was being fitted , so fully up to speed with whats going on , TBH , I have no idea why it's rubbing !
We have sold plenty of these kit with no one coming back and saying it's rubbing , Duncan has already fitted these kits to other cars , with no rubbing , so we are both at a loss.
Just to dispel any of the things already said , no our bells are not thinner making the wheels go in further , in fact the bell is 0.7mm thicker , I like to have at least 7.5mm wall thickness for strength , i'd rather my kits over engineered and strong rather than the other way round , we do take them thinner on race and rally cars to save a tiny bit of weight , where saving weight is a priority , so as the wheels are out 0.7mm further than standard , it will be interesting to see if a spacer makes it worse.

I have just bought an M2 , and i'm having spacers delivered today as I want to bring the wheels out to fill the arch , and on them the tyres catch on the front of the liner , but that is with 15mm spacers , i'm wondering if the 0.7mm is creating the same affect on your car , with the wider than standard tyres , and if it does , it must have just been on the limit of catching with the standard brakes.

If duncan finds it an issue with the bell being 0.7mm thicker , I can make you a pair of bells with exactly the same thickness as the standard discs and see if it cures it , i'd be amazed if that was the issue , but if it is , it's an easy fix
Cheers Ian

Great customer service. I’ve ran my Godspeed kit for 1000miles now, also fitted by Duncan. Can’t say I’ve noticed any rubbing but will definitely be checking when I return from holiday. Presumably the offer to replace the bells extends to all customers (if affected)?

Also, just ordered rear kit.

 

[Godspeed]

Great customer service. I’ve ran my Godspeed kit for 1000miles now, also fitted by Duncan. Can’t say I’ve noticed any rubbing but will definitely be checking when I return from holiday. Presumably the offer to replace the bells extends to all customers (if affected)?

Also, just ordered rear kit.

yes if anyone else is affected , we will swap the bells , but if you haven't noticed it in a 1000 miles , it's not doing it , I can't see why 0.7mm would make them rub on Sonics car , but to eliminate any doubt , i'll change them
Got your rear order thanks
Cheers Ian

 

[Sonic]

Fitted Bola 18x8 alloys to front and did some slow turning. Clunking from NS at full left lock. Grinding from OS at full right lock. I was hoping the 42 offset of these might help, but it's obvious that the same issue appears across all of my wheel sets.
Note - I've just spent 10 minutes slowly driving around the Odeon car park engaging full left and right lock. The NS hammering/knocking on a left turn and the OS grinding on a right turn only happens when going forward. When I engage full L/R steering lock in reverse there are no sounds. Why might this be? It seems to defy logic in my mind ...
[Subsequent edit. See later posts: Noise caused by scraping. Forward motion will apply force on wheel towards wishbone, Reverse will pull wheel away from it - that's my theory. ]

Anyhow, I've bought a cheap set of 5mm spacers from Amazon so as I can experiment again tomorrow (weather dependent). The car is then off to Skidz on Monday (tyres) and Hypertech on Tuesday evening (more head scratching diagnostics maybe).
Thanks to all for their input so far

Anyway,

 

[Godspeed]

That is strange !
I cannot see how a 0.7mm difference in bell thickness can cause all these issues , if it was the bell , it would do it forwards and backwards.

Sounds to me there could be play in a bush or ball joint , on full lock driving forward , the forces of the road are pushing the wheel backwards causing it to rub , when reversing its pulling the wheel forwards , not by a lot , but enough to catch , or play in the steering rack allowing the wheel to turn more than it should , can't really think of any other reason it would do this.

I've been rallying for over 30 years , and had issues similar with rose joints wearing or breaking apart

Can you feel any play in the wheel at all pulling it about by hand , put it on full lock and see if you can push the wheel back further

 

[Sonic]

Can you feel any play in the wheel at all pulling it about by hand , put it on full lock and see if you can push the wheel back further

@Godspeed No play at all. It’s as solid as…
I’ve got to get the car back across to Duncan tomorrow anyway (even with that storm warning in place) as I discovered this afternoon that the NSF caliper is now leaking brake fluid
We’ll see what happens next week. #emotional

 

[Godspeed]

@Godspeed No play at all. It’s as solid as…
I’ve got to get the car back across to Duncan tomorrow anyway (even with that storm warning in place) as I discovered this afternoon that the NSF caliper is now leaking brake fluid
We’ll see what happens next week. #emotional

Probably the banjo bolt on the pipe is not tight enough , or a bleed nipple, turn the wheel fully , and see if you can just nip it up to stop the fluid doing any damage

 

[Orro]

If these calipers fit on the standard discs is it worth putting them back on to see if the issue is still there?

 

[Sonic]

Recorded some sound clips for Youtube. No longer required as I've found the problem - Rotors are rubbing on the lower wishbone at full lock (see below).

 

[Sonic]

For @Godspeed: I got to thinking about metal to metal contact and steering arms etc. So I did some more ‘static’ testing. I was correct. It’s nothing to do with tyres. The rotors are rubbing against the lower control arm/wishbone. Screenshots below:
Offside first. Source of loud grinding at full right lock.

Nearside. Sound of light rubbing and knocking. I reckon the knocking is the arm falling into the etched pattern as the disc rotates?

It may be touching elsewhere too but my simple fault finding has at least found an issue. I’m not sure what the resolution is here apart from increasing the offset of the whole rotor kit and brackets. I do wonder if it's because they are 'floating' discs though rather than bolted; as maybe the floating brackets/clips (I don't know the correct term) are adding some extra mm shift inboard that a bolted hub wouldn't have?
Anyway, I’ll wait to see what @Godspeed and Hypertech come up with.

For info: The OEM 'depth' from internal hub surface to the back of the disc measures around 51mm by my crude estimate today. I can't measure the fitted ones. Here's a picture of the removed OEM rotors..

 

[Beans]

I got to thinking about metal to metal contact and steering arms etc. So I did some more ‘static’ testing. I was correct. It’s nothing to do with tyres. The rotors are rubbing against the (control?) arm/frame of the steering. Screenshots below:
Offside first. Source of loud grinding at full right lock.
View attachment 31892

Nearside. Sound of light rubbing and knocking.
View attachment 31893

It may be touching elsewhere too but my simple fault finding has at least found an issue. I’m not sure what the resolution is here. I’ll wait to see what @Godspeed and Hypertech come up with.

Is your car lowered @Sonic ?

Looks like you'll need to space the disc further out rather than in. Find it a bit odd though as there will have been heat shields there before? (which are much bigger than 0.7mm!)

 

[Sonic]

Standard suspension. Not lowered. Leak of fluid is from Caliper pistons on NSF, everything else is tight - the presence of fluid leaking down over the bracket would seem to indicate that the piston seals are gubbed. The harder I use the brakes the bigger the leak?
As for the kit, worse case is that the front brakes (and brackets) need to be re-engineered for a slightly greater offset. I don't know what the new ones are but I measured the OEM set from hub inner surface to the rear of the disc and it was about 51mm (see added photo in my post above).

I may have to have the whole lot removed and revert to the OEM fit if this problem is going to take some time to resolve. As it stands I can’t drive the car with a leaky caliper and scoring rotors - even turning into my driveway results in that horrendous grinding sound; so it's now parked up until we get an answer. Duncan at Hypertech said he is is going to have a chat with Ian at Godspeed tomorrow.

In the interim I'm gonna need some Dinitrol underseal and a Bus Pass
To finish on a positive note though, now that I've found where the problem lays I don’t need to buy a set of 215 tyres!

After a brief Brain Fart here's my own 'Pause for Thought': Could be the floating disc clips have shifted the offset to the inside by just enough to cause this?
Image: Floating vs Bolted. Could this extra space be my issue? Answers on a postcard to ...

 

[Godspeed]

Morning

The first question in my mind was has it been lowered , same as Beans asked , as this will change the angle of the track control arm and cause issues , if you say no , then there must be a slight variation of the metal arms causing it to rub , we have sold aver 25 kits for the GT86 and BRZ , and no one has come back and mentioned rubbing , this kit is our Impreza kit , and over the years we have sold probably over 1000 kits , with no rubbing , but the impreza's do use a different alloy arm.

I'll redesign the GT86 kit to give more clearance between the disc and arm , so 1-2mm less offset on the bells , and a change in the brackets , so it'll give more clearance on the bottom arms , and keep that design moving forward.
I'll get more bells made today ( I made 3 pairs with the 6.7mm thick front face on Saturday , but can use them on the Impreza's ) and up the anodisers , and will ship a pair of discs and bells up to you towards the end of the week , i'll have the original discs and bells back off you.

And if we can get to the bottom of the caliper leaking , I spoke to Ben who does the calipers and he's confident it's not a piston leaking , as we pressure test every caliper we build , hopefully it just a nipple of pipe that needs retightening , if it's a caliper we'll get another one to you as well , will need an answer on that asap as one will need to be powdercoated to suit.

To answer the question regarding the difference in bells between the bolted or fully floating , the fully floating bells have 2mm less offset to allow for the bobbins , so the total offsets are the same , same goes for all the kits we make for all cars.

Just to add , while writing this out , i've spoken to sonic , and just got off the phone to Duncan , Duncan has said the lower arm is catching slightly more on one side to the other , and only just catching on full lock , doesn't catch going straight , so will be a variation in the metal arms , so we're making bells with 1.5mm less offset , will get them on the CNC lathe within the hour , and he said the N/s lower piston is leaking , so we're powder coating another caliper today to swap , be interesting to see why it's doing that , as these Brembo's are very reliable

Never a dull moment !

Cheers Ian

 

[Sonic]

@Godspeed thanks for the informative chat this morning, it was great to be able to talk to a real person, both with a passion for their craft and with strong customer service at its heart. It certainly makes a change from the usual faceless corporations so prevalent in today’s marketplace.
Good to know that my, and others, technical ramblings within this forum haven’t gone unnoticed - another benefit of choosing a ‘local’ UK based bricks-and-mortar business over just a website.
As discussed today, there’s around 15-18mm of space between the Caliper and the back surface of the OEM wheel spokes, so plenty of offset to play with if needed. I can certainly fit my fingers, or a budget cheese sandwich, between the two. I only wish I’d placed a Banana for scale

 

[ZN8]

@Godspeed I'm assuming this only affects the smaller Brembos calipers that Sonic has fitted as no one else has mentioned issues using the Megane RS3 calipers, how different are the discs on those?

 

[Godspeed]

@Godspeed I'm assuming this only affects the smaller Brembos calipers that Sonic has fitted as no one else has mentioned issues using the Megane RS3 calipers, how different are the discs on those?

Hi
All the bells we've done on this car are the same offset , which ever caliper is used , but no one has had this issue , to save any issues in the future , we're modifying all the bells we make for the GT86 by 1.5mm less offset , will never be an issue again
Will be making a new batch of these as well as we have the Meg 3 calipers back in stock now , non of the bells will go to waste as they fit perfect on the Impreza's
Cheers Ian

 

[ZN8]

My only slight annoyance currently is a grinding noise from the outside wheel when at full lock (so left wheel when turning right and vice versa). I'm sure this is just a shroud or dust shield or similar, but no major concern for now. Doesn't make any noise under normal driving, just low speed and full lock. (If anyone has any ideas, I'm all ears, but I'll get it looked at ASAP).

@S18RSG Did you get this sorted? Guessing it may be the same issue as Sonic had.