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Other Resources => Component Deals & Selection => Topic started by: ZacItaly15 on February 13, 2025, 05:41:20 AM

Title: ZRACE XG2 CALIPER DOT FLUID SWAP
Post by: ZacItaly15 on February 13, 2025, 05:41:20 AM

Dear all
as you may know, the Zrace XG2 caliper are only available in mineral fluid options...but I want to install on a Sram Apex groupset.
So, I discover via youtube the inner piston of Zrace is 22 mm diameter

What do you think to swap the inner seal from mineral to dot (22mm standard seal I hope to find...) ?

Title: Re: ZRACE XG2 CALIPER DOT FLUID SWAP
Post by: Sebastian on February 13, 2025, 08:32:18 AM

Not sure if that works. In theory it’s only the seals that make the difference. After all Hope do their calipers in both versions. I’d be very interested in your experiment. Let me know if you try it.

Title: Re: ZRACE XG2 CALIPER DOT FLUID SWAP
Post by: DavidG on February 14, 2025, 01:09:52 AM

Interested to hear how you get on. I bought these same zrace calipers myself but a SRAM Rival AXS in the bike.

Title: Re: ZRACE XG2 CALIPER DOT FLUID SWAP
Post by: ZacItaly15 on February 14, 2025, 02:37:08 AM

I have a written confirmation by Hope you can swap the seal and convert Hope RX4 / RX4+ (and I suppose all the hope caliper)
So, I suppose the only impact of DOT / Mineral is in the seals and not in the piston or body

Zrace use the same Shimano piston (100% compatible) 22mm but i'm struggling to find 22mm DOT seal. The closest are the 21mm DOT by Sram.

Title: Re: ZRACE XG2 CALIPER DOT FLUID SWAP
Post by: glepore on February 14, 2025, 08:20:16 AM

If its an oring seal, plenty of epdm orings available. https://www.google.com/search?q=epdm+22mm+oring&rlz=1C1CHBD_enUS854US857&oq=epdm+22mm+oring&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIHCAEQIRigATIHCAIQIRigATIHCAMQIRigATIHCAQQIRigATIHCAUQIRiPAjIHCAYQIRiPAtIBCTc0OTZqMGoxNagCCLACAfEFon3VMmHWPO4&sourceid=chrome&ie=UTF-8

Epdm is DOT fluid compatible.

Title: Re: ZRACE XG2 CALIPER DOT FLUID SWAP
Post by: Sebastian on February 15, 2025, 04:29:14 AM

No, it's not just a simple O-ring. At least not in Sram's case. Take a look at their piston service kit. The seal is more like a rubber washer with flat edges. The seal is actually pretty important for correct pad retraction. It's the only thing pulling the pistons back into their zero position after you released the brake. So I don't think an O-ring would work.

Now obviously I have not taken the ZRACE calipers apart. So I dunno what's in there.

Title: Re: ZRACE XG2 CALIPER DOT FLUID SWAP
Post by: Sebastian on February 15, 2025, 04:35:02 AM

The seals for Hope calipers have a flat washer-like shape as well

Title: Re: ZRACE XG2 CALIPER DOT FLUID SWAP
Post by: glepore on February 15, 2025, 07:53:50 AM

22.5 here:https://brakecrafters.com/collections/motorcycle-brake-caliper-seals
There are a couple others but it'd help to know the bore diameter. Tons of silicone 22mm seals on ali that are allegedly "motorcycle" which is dot, but supposedly silicone isn't dot resistant.

Title: Re: ZRACE XG2 CALIPER DOT FLUID SWAP
Post by: ZacItaly15 on February 17, 2025, 07:17:40 AM

of course, they are called quadri-ring due to the not-toroid shape. But I'm pretty sure that any DOT compatible seal can works
https://it.aliexpress.com/item/1005005666514186.html?pdp_npi=4%40dis%21EUR%213.30%213.30%21%21%213.33%213.33%21%4021011b4917386956159962231d1170%2112000033947668161%21affd%21%21%21&dp=EAIaIQobChMIgo6bjeXKiwMVS52DBx0SuyH5EAQYBiABEgK8dfD_BwE&gad_source=1&gclid=EAIaIQobChMIgo6bjeXKiwMVS52DBx0SuyH5EAQYBiABEgK8dfD_BwE&aff_fcid=5ad4e774f4c141b89d412fc9db9ec4e1-1739798136171-06384&aff_fsk&aff_platform=api-new-product-query&sk&aff_trace_key=5ad4e774f4c141b89d412fc9db9ec4e1-1739798136171-06384&terminal_id=577d47f5d55f4262999ba78823360f92&afSmartRedirect=y#nav-description

here I found a 22mm inner diameter , but I'm not sure about the external diameter.
I just did some maintenance to my motorcross bike caliper and I know how this stuff works

Title: Re: ZRACE XG2 CALIPER DOT FLUID SWAP
Post by: glepore on February 17, 2025, 08:28:15 AM

Again, be careful of silicone seals with standard dot fluid...they're not compatible.

Title: Re: ZRACE XG2 CALIPER DOT FLUID SWAP
Post by: ZacItaly15 on February 17, 2025, 09:21:05 AM

Yes definitely.
That's why I'm looking for automotive/motorbike application seals.
I'm aware the rubber softness, temperature profile etc etc may be far different from long lasting automotive needs and recreational cycling use

Title: Re: ZRACE XG2 CALIPER DOT FLUID SWAP
Post by: Sebastian on February 26, 2025, 01:07:12 AM

Any update on this?

Title: Re: ZRACE XG2 CALIPER DOT FLUID SWAP
Post by: Serge_K on February 26, 2025, 09:25:17 AM

wow, you must really, really want to use these ZRACE calipers.
Swapping oil platforms sounds like a massive downside, little upside trade to me, i'd never venture down that road, but if you really know what you're doing... Upside, you get to use Zrace calipers. woo-hoo. Downside, you die.
Are you sure about that? Do you trust yourself enough not to ever fear that maybe today is the day when your brake swap comes to bite you and your calipers wont stop you that one time when your life depends on it?

Title: Re: ZRACE XG2 CALIPER DOT FLUID SWAP
Post by: ZacItaly15 on February 26, 2025, 02:40:30 PM

I agree, so I abort this foolish idea.
Meanwhile, for mineral lovers...
https://it.aliexpress.com/item/1005008542998104.html?spm=a2g0o.productlist.main.1.4baee5f2QRed0J&algo_pvid=1413b2e5-2d5e-42a9-9738-cd4ce9cee83e&algo_exp_id=1413b2e5-2d5e-42a9-9738-cd4ce9cee83e-0&pdp_ext_f=%7B%22order%22%3A%22-1%22%2C%22eval%22%3A%221%22%7D&pdp_npi=4%40dis%21EUR%2151.69%2151.69%21%21%2153.09%2153.09%21%40%2112000045639662299%21sea%21IT%21709311833%21X&curPageLogUid=gTHChIm4aPv1&utparam-url=scene%3Asearch%7Cquery_from%3A