nardeezy

I will be highly interested in purchasing and installing big brakes. A few questions:

1) F-Sport brakes are spec'd for the GS350, would they be compatible with the GS300?

2) Visually, my iforged wheels have a generous amount of clearance with the current brakes, how will I know if aftermarket big brake systems will fit? I called iForged and they said my wheels are not aftermarket big brake system friendly. However, visually there is a lot of extra space between the inside face of the wheel and calipers, and the ID of the wheel and OD of the rotors?

rominl

iTrader: (4)

you need the caliper profile diagram to see if it fits for sure, that's the only way

nardeezy

How do you obtain a caliper profile diagram?

rominl

iTrader: (4)

with other bbk (brembo, ap racing, stoptech), you can request from manufacturers for the profile diagram so you can do some cardboard experiment to make sure

but on the f sport i don't know. i believe they are made by stoptech, however i don't know if stopteh can give you that information

in general you need your front wheels to be high disk to consider fitting over bbk. for example gs350/450h/430/460, unless you get high disk front wheels, they don't even fit.

look at your front wheels now, from the face of the gs300 calipers, how much space do you have between that and the back of the spokes? how about roughly 8" away from the center of the wheel, how much space do you have between the caliper and the back of the spokes?

passnu2

iTrader: (33)

you can always add a spacer if they dont fit. A 3mm spacer or worst case a 5mm spacer should do the trick if you have enough room with your current offsets now.

Piranha12

I went to Sewell's online and found the F-Sport upgrade, they told me it will fit on my GS350 but of course i'll need to have bigger rims for summer and winter times.

The GS350 OEM rim size is 13.1 inches in the front and 12.1 in the back, but the upgraded rotor sizes are 14.2 in the front and 13.6 in back.

I'm sure the F-Sport upgrades will fit on your GS300 you just need to make sure to have big rims for the upgrade. The IS-F has 19inch rims and the same rotor size, so i believe and correct me if i'm wrong; but if you have 19inch rims are bigger the F-sport rims should fit.

http://www.sewellpartsonline.com/par....asp?id=187555

rominl

iTrader: (4)

diameter is just the easy part of the equation. for 14.2" rotor bbk setup, actually some 18s will fit no problem. look at the is-f forum, some people have 18s for winter wheels. but it will be very close with 18s, not all will fit. for example the stock 18s, diameter wise, is not large enough and just miss clearing the brakes (calipers)

but when fitting wheels over brakes, the spoke profile is usually the biggest problem. all bbk have very big calipers, sticking out quite a bit from the rotor hat ("height" wise). therefore the wheels need to have special spoke design that clear the calipers. otherwise the spokes will hit the caliper before the back plate sits on the hat

rominl

iTrader: (4)

here's a good example (or it might make things even more confusing)

is350 stock brakes are very big already, you can consider them bbk. is350 has 18" wheels

is-f has big brakes by brembo. the car comes with 19" wheels

the 18" is350 wheels do NOT fit on the is-f front. problem is the wheel overall diameter isn't large enough and it just rub ever so lightly with the outer part of the calipers on the is-f

on the other hand, the is-f 19" wheels do NOT fit on the is350 either! surprisingly, the is350 calipers have larger profile, so although the is-f wheels are 19" and diameter wise it clears with flying colors, the spokes do not entirely clear the face of the calipers

nardeezy

Thanks rominl! I'll just need to take my Mitutoyo digital calipers to the wheel/brake assembly tonight. Again, I looked at it visually and I think I have enough space. From the diameter perspective, the only thing that will get in the way is the valve stem. However, at the nearest collision point between the valve stem and front brake caliper, it appears to be at least 1.5-2.0" clearance. The inner spoke plane to the caliper has at a minimum 0.25"-0.5" clearance.

What do you think?

rominl

iTrader: (4)

hahhaa, digital calipers won't help unless you are down to those mm already

valve stems? oh boy, are you talking about those vertical valve stems inside the barrel that stick straight up? they are painful specially when you have bbk. but since you have 20s i think you are fine (my guess), i recall my friend with 20s and stoptech brakes, and those are 14" rotors.

on the distance between caliper and spoke, 0.5" probably won't cut it at all, unfortunately. i think you need at least 20 to 25mm to stand a chance. another example, on my gs400, stock brakes are tiny (very similar to your gs300 i think), and the stock 17s fit just over those brakes. later on i put ap racing brakes on the car. in order to fit the stock wheels on and clear the calipers, i had to put 25mm spacers. 20mm would clear but it's too close to be comfortable with

another reference point for you

nardeezy

Actually my calipers go up to 6". Hmmm... 2.0-2.5cm (up to 1")? I will definitely need to measure.

oem

iTrader: (1)

u need a 3mm spacer in the rear