GS Front Brakes Upgrade for IS250

[BillNick]

Hi all,

Seen a few members with front brakes from the GS.

Can anyone please advise me what is involved with this upgrade?

Which model and year range of GS please, and do the calipers and discs go straight on, or does anything need modifying or customising?

I have a 2008 IS250 SE-L

Thanks

Bill

[Linas.P]

All you need to know... I need to bookmark this, but so far google always helps me out:

https://www.clublexus.com/forums/suspension-and-brakes/405811-is350-brake-upgrade-on-is250.html

IS350/GS350 and GS300 mk3 and mk2 have same size calipers which are interchangeable, but has different look. For "big brake kit" look you really need IS/GS350 calipers, GS300 is just bigger. 

[J Henderson]

Done this upgrade to my car last year and its one of the best things I've ever done. There's lots of pics and info of the process in my build thread.

 

https://www.lexusownersclub.co.uk/index.php?/topic/112594-My-IS250-F-Sport#entry1053919

 

But, basically it's a straightforward bolt-on swap with only one small modification required.

 

 

That small triangular piece of metal needs to be trimmed from the dust shield to accommodate the bigger caliper.

 

I imported actual IS350 calipers from the USA (rockauto) just to be certain, but as Lines says, the same brakes are on other Lexus models. I believe all GS450h cars have these brakes, also 200T models etc.

 

 

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[BillNick]

Thanks very much!

I look forward to reading your thread.

[Texas]

J Henderson, Can I ask what leads you to say "its one of the best things I've ever done"?

I know the 250 brakes and be a bit 'grabby' and sometimes I feel as though any passengers in the car may think it's my braking methods when in fact it is not! So is this 'grabby' feeling down to the size of the disc or the size of the pads (or both)  in some way? And are you brakes now nice and smooth in their actions? not that the 250 brakes aren't there when you need them! Just an art to apply them smoothly!

paul m.

[BillNick]

I have almost new OEM discs and pads (3-4000 miles in) and they seem find on smooth soft braking, but as soon as you apply a bit of harder pressure or need to stop quickly, they pulse, like the pads are only making contact on one part of the disc.

No wobble in the steering wheel however, so I think it could be the rears (also supported by the fact that it only happens when you put on full anchors).

How would you describe your 'grabby' sensation?

[Texas]

It's like slowing down from say 50-60 to a stop and at some point just before the actual point of stopping it's like some extra pressure has been applied ( not by me) and the brakes work a bit harder, similar I say to if you was braking to stop at a point in the distance and at some point a hazard was spotted, you would up the pressure to reduce your stopping distance but I'm Not upping the pressure! Like I said passengers might think 'why did we do Extra braking there for No reason'

hope the description makes dome sort of sense.

paul m.

[BillNick]

Does make sense yes, different to my issue it seems.

When was the last time your car had a full brake fluid replacement? That can make hell of a difference. Air builds up in the fluid over time so they recommend replacement every 2 years.

Both issues very odd and annoying to say the least.

[Texas]

I understand the importance of tip-top Brake fluid and I would of thought that deteriorating fluid would make the braking effect Worst not momentarily Better!

paul m.

[Linas.P]

I haven't done it, but I generally think that IS250 brakes are undersized for heavy car. I mean IS350 is not that much heavier, but has massive brakes. As much as I looked into it, many people agree and the ones who have done it as well mentions that as one of main "practical" benefits, the rest is just for additional confidence - it is not like one races IS250 so such large brakes not necessary needed simply for stopping. I personally don't have issue with braking power, but if I would do the upgrade I would do it from maintenance perspective. IS250 just chews through the brake disks like cheese, one almost need to change the disks when changing pads and the dust from pads again is massive issue. Having much larger brakes would mean much reduced wear and hence less maintenance and less dust.

[J Henderson]

@Texas

Yes, your assumptions are correct. The bigger brakes are exactly how you have imagined there.
They're no longer grabby and operate way more smoothly than the stock setup. Even if you don't thrash your car and brake hard all the time, their extra stopping power can be felt.

One of the more noticeable instances I observed was how easily you can now hold the car at a set of traffic lights on a cold day. Normally, when the engine was still cold and idling at 1200-1500 RPM, you had to press the brake pedal quite firmly to avoid it creeping forward, but now it stays put with a normal amount of brake pedal pressure.


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[Texas]

👍

[BillNick]

Just ordered some 450h calipers £130 posted

Will get em fully refurbished in black

Cant wait!

[Lex_utor]

Sorry about bumping an old thread up. But this thread came up on a google search about brake upgrades for the IS250. So I thought I might as well ask it here rather than starting a duplicate thread. 🙂

MOT time is coming and I will need to do my brakes. Since I'm not 100% happy with my brakes, I was thinking of upgrading to the GS350 front calipers and 334mm rotors.

My question to those who have done the upgrade is, do you feel any difference in the speed/performance of your IS250? The GS350 rotors are heavier and the calipers are probably heavier too. This is unsprung weight. So I wonder if you feel any difference?

The rear I will leave the same rotors and calipers. So just do the pads. Even though I seem to have the smaller one which comes with the IS250. It seems some come with 310mm. My rear ones are definitely smaller. But I think the front will be enough.

 

Thanks as always gentlemen. 🙂 

[J Henderson]

The GS calipers are actually significantly lighter since they're aluminium compared to cast iron, but yeah the bigger rotors are heavier than stock IS250, so it more or less balances itself out.

It's a great upgrade. One thing I'm not convinced by though is the durability of OEM Lexus discs. I've gone through 2 pairs that have developed issues prematurely. I now have EBC discs and Yellowstuff pads.

Sounds like you might have solid discs on the rear. The 310mm ones are vented.

[Lex_utor]

8 minutes ago, J Henderson said:

The GS calipers are actually significantly lighter since they're aluminium compared to cast iron, but yeah the bigger rotors are heavier than stock IS250, so it more or less balances itself out.

It's a great upgrade. One thing I'm not convinced by though is the durability of OEM Lexus discs. I've gone through 2 pairs that have developed issues prematurely. I now have EBC discs and Yellowstuff pads.

Sounds like you might have solid discs on the rear. The 310mm ones are vented.

Thanks. That's great to know the weight balances it out. 🙂

I don't think I will go OEM discs. Somebody who does drifting recommended Rotinger discs as a cost effective but great performance option. As they have models for the GS350 in 334mm which are both ventilated, slotted and perforated they look very nice as well as a bonus. Carbon coated. They are 334mm dia. and 30mm thick, so same dimensions as OEM as far as I know. Seems like they would fit. Have you heard of them?

Yes, my rear discs are solid. Do you know their dimensions? Rotinger also has the same discs for the rear, in 310mm x 18mm. Would they fit the rear? Price is not really an issue compared to OEM. Although not sure it's worth it larger/heavier discs at the rear for acceleration?

For the front I'm just a little concerned if they will fit under my winter wheels, which are 18". My summer wheels are 19" so I guess enough space there.

[Lex_utor]

I'm also debating whether I cut the back shield plates or buy new GS350 ones. I couldn't find the part numbers yet to price them new. 

[Lex_utor]

For the discs, if OEM, I heard the AWD discs won't fit? Is this the correct OEM discs for the IS250 upgrade? 43512-22261 & 43516-22011.

[J Henderson]

Haven't heard of Rotinger, but I believe the solid rear discs are 291mm or thereabouts. If you wanted to upgrade to the vented setup, you would also need new calipers (Vented ones are different).

As for wheel clearance with the bigger front brakes, It might be touch and go. The OEM Lexus wheels ("8 wide, +45 ET offset) barely clear the calipers with only a few mm to spare behind the spokes. Meanwhile, 19" IS-F wheels (also 8" wide & +45 ET) will not clear the brakes without a 5mm spacer. 

I don't really have any pics that show just how little space there is between spokes and caliper, but believe me, it's very close. Worst case scenario, you would need a 5mm or so spacer. There's plenty of room, circumference wise, with 18" wheels.

The backing plates were around £20-25 each when I was contemplating getting them. I would've got them but fitting them involves removing the hub and I didn't want to deal with that.

[J Henderson]

The last pair of rear discs I bought were this part number;

42431-30290

[Lex_utor]

19 minutes ago, J Henderson said:

Haven't heard of Rotinger, but I believe the solid rear discs are 291mm or thereabouts. If you wanted to upgrade to the vented setup, you would also need new calipers (Vented ones are different).

As for wheel clearance with the bigger front brakes, It might be touch and go. The OEM Lexus wheels ("8 wide, +45 ET offset) barely clear the calipers with only a few mm to spare behind the spokes. Meanwhile, 19" IS-F wheels (also 8" wide & +45 ET) will not clear the brakes without a 5mm spacer. 

I don't really have any pics that show just how little space there is between spokes and caliper, but believe me, it's very close. Worst case scenario, you would need a 5mm or so spacer. There's plenty of room, circumference wise, with 18" wheels.

The backing plates were around £20-25 each when I was contemplating getting them. I would've got them but fitting them involves removing the hub and I didn't want to deal with that.

Thanks. None of my wheels are stock. So I will have to check the ETs.

For the rear discs, if I need to change the calipers too, I will just keep it as is. The fronts do the work anyhow. 

[Lex_utor]

19 minutes ago, J Henderson said:

The last pair of rear discs I bought were this part number;

42431-30290

Thanks. Are those ventilated or solid?

Would you have the part number for the front upgrade ones?

[J Henderson]

Those are vented.

Front GS disc numbers;

43512-22260

43516-22010

[Lex_utor]

2 minutes ago, J Henderson said:

Those are vented.

Front GS disc numbers;

43512-22260

43516-22010

Thanks. I will need solid then, as I really don't want to change the rear calipers. Do you see any loss in keeping the solid ones at the rear? Will check lexuspartsdirect for their numbers.

Those are GS350 discs? I had found different numbers on lexuspartsdirect: 43512-22261 & 43516-22011.  As the numbers are so close, maybe this is a variation of the same discs? Those are for the 334mm ones.

[Lex_utor]

By the way, your car has the F-Sport 18" rims right? Surprised the fit is tight as I think the F-sport brakes are just the GS ones?