Titanium brake shims.

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Discussion

Zoobeef

Original Poster:

6,004 posts

158 months

Friday 19th June 2020
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Does anyone know a cheap place to buy a 150mm x 200mm x 0.5mm sheet of grade 5 titanium?

Emailed a few places and only 1 came back with a price that was for 1mm thick for some reason at £125 + £25 postage (I'm guessing they were sending it via private jet).

Which seems a little steep.

Cheers.

GreenV8S

30,186 posts

284 months

Friday 19th June 2020
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My local stockist quoted 150 for 300mm square similar thickness so I think you'll find that's about the going rate. It's pricey stuff.

Zoobeef

Original Poster:

6,004 posts

158 months

Friday 19th June 2020
quotequote all
GreenV8S said:
My local stockist quoted 150 for 300mm square similar thickness so I think you'll find that's about the going rate. It's pricey stuff.
Cheers, it may be worth buying a ready made set for another car and trimming them to fit then as that may save a bit of money!

I cooking brake caliper seals within a season so I'm going to add more cooling but thought I'd put the shims in to help also.

GreenV8S

30,186 posts

284 months

Saturday 20th June 2020
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If you're overheating the pistons, make sure the pads don't wear down too far - the pad material gives a significant insulating effect. And more air flow will obviously help if you can arrange it. I considered putting a circulating flow system on the brake circuit because I was cooking the fluid in the calipers, but didn't take that route in the end. Depending on your application that might help too.

Zoobeef

Original Poster:

6,004 posts

158 months

Saturday 20th June 2020
quotequote all
Thankfully I've never had any issues with fade or boiling. I've just noticed that my pad wear has gone up considerably and I'm having to replace the seals often.
This is because I've gone from 140bhp-200bhp-240 and now 260 so I expect the pads to wear faster but as its cooking the seals I'm guessing the heat is too much for the current cooling. So if I can sort that out hopefully the pads won't actually wear quite as quickly also. Ideally I'd replace the brakes for larger ones but as the car has become pretty much a once or twice a year use car im hoping reducing the heat will help pad life and seals for a relatively small outlay.

E-bmw

9,195 posts

152 months

Saturday 20th June 2020
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TBH I am not sure why you suddenly think you need titanium shims?

Zoobeef

Original Poster:

6,004 posts

158 months

Saturday 20th June 2020
quotequote all
E-bmw said:
TBH I am not sure why you suddenly think you need titanium shims?
Because I'm cooking the seals and the shims help deflect the heat from them.

GreenV8S

30,186 posts

284 months

Saturday 20th June 2020
quotequote all
If you aren't boiling the brakes, you probably aren't overheating the seals. Have your calipers got dust seals fitted?

Zoobeef

Original Poster:

6,004 posts

158 months

Saturday 20th June 2020
quotequote all
GreenV8S said:
If you aren't boiling the brakes, you probably aren't overheating the seals. Have your calipers got dust seals fitted?
Rears have, fronts don't.
Rear dust seals go brittle in less than a season. Just refurbed the fronts and the outer (interal) seals in those was quite brittle too although as its not an external dust seal it wasnt as bad.

GreenV8S

30,186 posts

284 months

Saturday 20th June 2020
quotequote all
Put some temp tabs on and see how hot they're actually getting. If they're decent quality seals it seems odd that they're suffering from heat damage without the calipers getting hot enough to boil the brakes.

Zoobeef

Original Poster:

6,004 posts

158 months

Saturday 20th June 2020
quotequote all
GreenV8S said:
Put some temp tabs on and see how hot they're actually getting. If they're decent quality seals it seems odd that they're suffering from heat damage without the calipers getting hot enough to boil the brakes.
I use RBF660 fluid, apparently RC6 pads do run quite hot but as they are so good I'd not like to change from those if I can. The rear discs are showing some signs of being pretty hot too!
I'll get some temp tabs though. I'm not using that car until September now so I hopefully will add the extra cooling before then.

SlimJim16v

5,650 posts

143 months

Sunday 21st June 2020
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I think stainless has similar heat conduction/insulation properties as titanium. It'll be cheaper, easier to get hold of but harder to work with.

Zoobeef

Original Poster:

6,004 posts

158 months

Sunday 21st June 2020
quotequote all
SlimJim16v said:
I think stainless has similar heat conduction/insulation properties as titanium. It'll be cheaper, easier to get hold of but harder to work with.
I assume grade 5 titanium is used as its better in mostof the critical areas than stainless. Although as you say would stainless be good enough.
Grade 5 titanium is lighter (negligible in these quantities)
Better thermal conductivity (as in conducts less)
Less expansion when heated (probably quite a critical one).
Other areas don't matter so much.

Given I need 2 x 90x60 pieces and 2 x 75x65 pieces it may be easier to get them individually as offcuts from somewhere.

stevieturbo

17,256 posts

247 months

Sunday 21st June 2020
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260hp is not a lot of power by any means.

What is the application that you are so heavy on the brakes that you think you are hurting the seals ?

And are you dragging or holding your foot on the brakes or something ? Log line pressure for front and rear.

Zoobeef

Original Poster:

6,004 posts

158 months

Sunday 21st June 2020
quotequote all
Its a vx220 racecar, circa 915kg with driver. In less than a season the dust seals are crumbling with signs of blueing and microcracks on the discs. All signs that there's alot of heat, along with accelerated pad wear.
I've tried OEM, eliseparts and a different supplier of seals. No draging brakes that I know of, I dont left foot brake but do trail brake.

The signs all point to excessive heat, bearing in mind I use standard calipers and standard sized discs.

Zoobeef

Original Poster:

6,004 posts

158 months

Sunday 21st June 2020
quotequote all
The shims 'may' protect the seals a bit better but not pad wear so I'm hoping extra cooling will help both with the shims as a belt and braces to protect the seals.

xjay1337

15,966 posts

118 months

Sunday 21st June 2020
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I'm surprised you're burning through the pad with RC6s.

I use RS29 and a 1550kg car with driver and 350hp and they get some hammering and the pad lasts forever.

Easily get 18 months of road and track use (maybe 6 trackdays per year). Infact the last set I had when I changed them there was still around 35% pad material left.

I've bought some shims to protect my dust seals which already look past their best (I'm probably going to upgrade to the 370mm caliper rather than rebuild) but anyway my shims are from Russia and cost me around £90 (for the 4 Piston blue bmw Brembo caliper).

Havent arrived yet...Russia is very slow🙄

stevieturbo

17,256 posts

247 months

Sunday 21st June 2020
quotequote all
Zoobeef said:
Its a vx220 racecar, circa 915kg with driver. In less than a season the dust seals are crumbling with signs of blueing and microcracks on the discs. All signs that there's alot of heat, along with accelerated pad wear.
I've tried OEM, eliseparts and a different supplier of seals. No draging brakes that I know of, I dont left foot brake but do trail brake.

The signs all point to excessive heat, bearing in mind I use standard calipers and standard sized discs.
When it is not a common problem elsewhere....it is likely your driving style, and you may be applying the brakes more than you think. Hence log it.

Or have you done something to remove or hinder any cooling of the front brakes ?

And incorrect pads/discs can also cause excessive heat./ Wrong pads on the wrong type of disc can be a problem.

Zoobeef

Original Poster:

6,004 posts

158 months

Sunday 21st June 2020
quotequote all
I get maybe 4 x 20 min races and quali and around 4 trackdays, whereas I used to get about 18 months when I had much less power.

This is an example of my driving style, its quite easy to see when I'm on and off the brakes from the SC whine.
https://youtu.be/7-EULFrCgFQ

Given I've retired it from racing for the time being the pads will probably last years now haha.

The Wookie

13,931 posts

228 months

Sunday 21st June 2020
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CL pads do generally run quite hot, id probably try a Pagid RS29 if it’s available as even a 260bhp car of that weight shouldn’t be troubling the brakes too much

The titanium shins are unlikely to do anything helpful. If the heat is getting through the 10mm steel back plates then one mm of Ti probably won’t help. You’re more likely to cause drag if the shims distort or aren’t perfectly flat

If you really want to keep the CL’s then just sort your cooling out, inner face of the disc and as close to the trailing side (Ie where the disc emerges as it’s rotating) of the caliper as possible

Make sure you’re using seals from the caliper manufacturer as well, it could just as easily be that the first time you replaced the seals they were from a different supplier and either not as thermally stable or simply has different characteristics which have resulted in less piston fallback, and thus more parasitic drag thus more heat.

If you’re going really crazy then you could either find some pistons to the same spec with venting holes on the lip, or you could get the seals angle machined to improve fallback and reduce drag at the expense of more free travel at the pedal