Wilwood PS-1 Brake Pads

[BMH]

Hello, we are looking into using the Wilwood PS-1 calipers for our next car. I have been looking into brake pads for the calipers and it appears that there is only one readily available, the BP-10 compound if I'm not mistaken. Does anyone know the friction coefficient for these pads, and what rotor material they work optimally with?

Has any teams used other brake pads?

[BMH]

Hello, we are looking into using the Wilwood PS-1 calipers for our next car. I have been looking into brake pads for the calipers and it appears that there is only one readily available, the BP-10 compound if I'm not mistaken. Does anyone know the friction coefficient for these pads, and what rotor material they work optimally with?

Has any teams used other brake pads?

[TacoPete]

The BP-10 pad is the only one I have seen for the PS-1's. Look through the pdf's on the site to find a couple of friction coeff. vs. temperature graphs.- I have always wondered what rotor material they were tested on though.

I have heard that some teams machine pads to fit these calipers.

[vandit]

we used Sintered metallic compound for PS-1 ....i saw on their website recently , they still offer that compound with PS-1 . It's a decent combination to start with.

[Adambomb]

I know I've posted a link to the PS-1 mu vs. temperature plot several times, this question comes up about once a year, but I just checked the "find" function and it hardly gave any results.

I can't really complain about people using the "find" function if I can't get that to work myself! What's up with that, I've noticed recently that the "find" function has been pretty crappy on other things too.

But yeah, here's the typical result I've seen for this exact question. Please don't anyone take it the wrong way, this is done tongue in cheek; the reponses have nothing to do with the current thread, these are just the core common things that come up EVERY TIME this discussion comes up (which is relatively often):


Person A: What is mu for PS-1 pads?

Person B: It's not posted anywhere, and Wilwood keeps it top secret. They probably don't even know it themselves. (pretty much every time I have replied I included a link to the mu vs. temp. plot that WILWOOD PUBLISHED for the pads...and it's not something I saved either, I just googled it every time...although if I posted it now it would take like 3 days for this post to get approved). Barring that, I have found Wilwood tech support to be very helpful.

Person C: What you need to do is machine down pads for something else. (BTW that's terrible advice IMHO, but that's coming from someone who a) has seen the mu vs. temp plots, and b) doesn't like to spend time machining brake pads when I could spend more time dialing in the car).

Person D: Wilwood PS-1's have terrible bridge compliance, seal friction, and friction lining Young's Modulus. The castings look ugly and they smell of elderberries. You want Brembos.


So with that off my chest ...There is a quite nice looking mu vs. temp plot out there, used to be on Wilwood's website, it's about 0.4 and pretty flat up to like 900 F. We've been using the PS-1s with BP-10 pads since 2006 and I'm happy with them.

[oz_olly]

I agree with Adambomb about the PS-1 calliper. We used them for the first time last year and I was very happy. Sure they don't look as good as a brembo or even a Wilwood Dynalite but they package really well, are light and seem to work very effectively.

My brake system design had the brake discs packaged on the inboard side of the upright in a 10 inch rim so they were only 180mm diameter. Because the PS-1 pad has a relatively low mu I ended up with fairly high line pressures. The system resulted in a very firm pedal much better than previous years car and passed brake test first go.

The thing I disliked most about the PS-1 is the fact that it comes with threads tapped into the mounting holes. This means you are quite likely to be putting a shear load through the threaded section of the mounting bolt. To fix this we drilled and reamed the threaded section and used a through bolt. Also as they were mounted the wrong way (due to inboard brake) it would have been nice if the brake line could be fitted on either side of the calliper. Small gripes about a great little calliper for FSAE.

I have not measured any of the parameters that apparently seperate a good calliper from a not so good one such as bridge stiffness, friction material compression modulus of elasticity (to know how much do the pads deflect for a given compressive load). We ended up using so much flex line due to lack of time that worrying about that sort of thing was only going to slow us down.

So maybe they aren't the ultimate intellectual masturbation calliper but they are great value for money, light and small.

Cheers

Olly

ACME Racing
UNSW@ADFA

[Adambomb]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by oz_olly:
The thing I disliked most about the PS-1 is the fact that it comes with threads tapped into the mounting holes. This means you are quite likely to be putting a shear load through the threaded section of the mounting bolt. To fix this we drilled and reamed the threaded section and used a through bolt. Also as they were mounted the wrong way (due to inboard brake) it would have been nice if the brake line could be fitted on either side of the calliper. Small gripes about a great little calliper for FSAE.
</div></BLOCKQUOTE>

Funny thing on this...we've gotten a few now that didn't have tapped holes. Looks like it depends on what options you get. Pretty sure the large piston/metric fitting ones had tapped holes, but the small piston/US fitting ones we just got this year didn't. Or maybe they just recently changed them. That sort of screwed us a bit since we were counting on threaded holes, actually ended up doing the opposite and heli-coiled them. Although the threaded holes are nice for clearance with our inboard rear brakes setup.