Saint M820 Frankenbrakes

Not an m820 caliper/XTRrace lever combo but I'm doing some mixing and matching as well.

I'm going to try a formula cura lever with a formula cura caliper, and use the same syringe I use with my shimanos to bleed them.

I'll let you know how it goes.

kidwoo said:

Not an m820 caliper/XTRrace lever combo but I'm doing some mixing and matching as well.

I'm going to try a formula cura lever with a formula cura caliper, and use the same syringe I use with my shimanos to bleed them.

I'll let you know how it goes.

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Interesting.

I went with a slightly different frankenbrake.

Magura MT5 lever, Magura MT5 caliper and and a set of modified Avid syringes that were previously used on Shimano brakes. Set up has been working perfect for two seasons.

Might be taking crazy pills, but my experience is that alloy backed pads can give up a little power. Have you tossed some good sintered steel pads in what you got and see how it works...?

After on and off brake woes this summer, I am going back to m810 saint brakes on the trail bike and calling it good. Nothing wrong with those babies, other than 50g extra

How about Saint levers for the XTR pots?

In my limited inexperienced, the 4 piston Shimano calipers are way moar trouble than the servo wave levers.

Graves ran that combo on his Yet for awhile, so did Santos. Santos gave it because it wouldn't hold a bleed. I recall reading that Graves' mechanic said bleeding the combo was tough.

I made a thread on this a while back as @Sandwich alludes to, and if you click the google sheet and scroll to the bottom there are some examples of franken combos which will give you an idea of what different things do.

I think the combination you want to use will work fine - if you're already happy with the consistency/reliability of the Shimano parts (some aren't, obviously) then in your case the result will just be more power and less throw. The throw won't be excessive since it'll still be shorter than a stock M820 brake (which in my opinion is excessively long).

I've tried the combo myself briefly (XTR Race lever on M820 caliper) and the throw is fine. Didn't test extensively enough to say much more, but I think it's worth a go. I'd find one M820 caliper and try it on the front first.

For discussion on other brakes I'd flick through that thread - the good ones are expensive though, so I'd try your idea on one end first.

@HAB minimal time on XTR trail, but plenty on the various current XTs and M820, and mathematically the XTR trail should be pretty well identical to XT in actual power (same 22mm caliper pistons, and the MC piston + servo wave profile aren't different to my knowledge).

I like the RO-R. I think they are comparable or more powerful than XT but aren't as powerful as M820. Much shorter throw than M820 and more consistent throw than both. The XTs have more initial bite but in my experience once you're actually moving the stopping power is in the same ballpark. I do like the Shimano heatsink pads more on long runs where glazing can be an issue - probably my one complaint about Formula in general.

The price difference will be quite substantial between the M820 caliper option vs. getting a complete top-end Formula brake though, and the majority of the benefit in the Formula is in its ridiculously light weight (200g for caliper/hose/lever bled). They're so much lighter than other brakes that you can often go up a rotor size if available/desired. I imagine those aren't things everyone desires though.

I'd honestly just try your original plan if I were you (especially if you've been relatively happy) - from what I've gathered the race levers are less problematic than the servo wave options. If splurging on Formulas I'd try a set in-person first.

Udi said:

I do like the Shimano heatsink pads more on long runs where glazing can be an issue - probably my one complaint about Formula in general.

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Swissstop has some finned pads for Formula. http://www.swissstop.com/DiscBrakes/Disc25/EXOTherm/
I never tried their stuff yet but this company is just making brake pads and is obviously based in Switzerland so that you can expect their pads to be made of top quality matured cheese!
More seriously, I will soon get a set of sintered ones for my Guide and can report on them if you're interested.

Just wanted to throw this data point out there. I'm on plain old Saint 820's. I haven't had the OMG-I'm-gonna-die bite point changing issue that others here have (I just occasionally have the usual symptoms of needing a bleed, and doing so generally fixes it), so I guess I have a good set. I did however have massive rotor squeal on any long/steep descents. They sounded like Avids! Thought it was the rotors, swapped them out for new Ice tech ones, and new pads, same issue. Finally tried switching to organic pads. Completely fixed the rotor squeal, no fading, same power, and waaaay better modulation.

So, mentioning this because you said you were thinking about the 820 caliper for more power, but preferred the non-servo wave lever feel. If that preference is based on better modulation, then you might just try a straight-up Saint 820 set with organic pads. YMMV.

Although I'm perfectly content with 820s, I've owned Formula The Ones and aside from the bleeding process I loved them. I put a few years on them, then sold them to @stoney who still uses them to this day. Those (or that feel specifically) with mineral oil and a simplified way to maintain would be winners.

HAB said:

Do you remember which model year?

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based on image search, 2010/2011?

Why do you guys keep messing around with Shimano and Avid brakes that don't work? There's got to be something out there that works. I know that you're sick of me promoting Hope, but is the market that shitty that no one else makes good brakes? This stupid topic seems to come up every month on here. Seriously.

I looked at Formulas site and saw they only make 4 brakes, none of which are 4 piston, but one -the Rawr!- is considered a DH brake. What about TRP, Magura, Hayes? Any others?
My Hayes Stroker Aces lack some of the power that my old Code's and V4's have, but are one of the easiest to work on and most reliable bike products I've ever owned. Just curious.

Nick said:

Although I'm perfectly content with 820s, I've owned Formula The Ones and aside from the bleeding process I loved them. I put a few years on them, then sold them to @stoney who still uses them to this day. Those (or that feel specifically) with mineral oil and a simplified way to maintain would be winners.

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They stop fat boy at speed. Es muey bueno!

still rocking saint m800 brakes. with same gen xt levers.

i've got a set of XT's (m785) on the spitty, and other than having so-so modulation, no issues

HAB said:

Cool story bro.

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as soon as i saw the notification that you quoted me in this thread, i knew this would be your exact response.

jonKranked said:

as soon as i saw the notification that you quoted me in this thread, i knew this would be your exact response.

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cool story bro

Sandwich said:

The organic pads kind of kill the functionality of the radiators, though.

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Huh? How so?

In any case, I've been super happy with Saint 820's but specifically with organic pads. Great power, and seriously the best modulation I've ever experienced (have run Avids/Maguras/other Shimanos in the past).

@HAB, I do hear you about the lever stroke though, it does seem like it's a bit long.

Also haven't experienced problems with the organic pads in the wet, other than momentary squeal, they still seem to work great. But I'm sure I don't ride in the wet nearly as much as you do up in the PNW. YMMV.

HAB said:

@Udi Thanks. I've been trying to find a pair of RORs to try with no luck. Everybody I know seems to be on either Shimano or Guides. The price difference is actually not that huge, especially when you factor in the potential for selling one of my sets of XTRs.

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I don't really want to be responsible for a bad experience and suspect they aren't for everyone which is why I'm reluctant to say "run out and get them", but I do quite like them personally (buckoW on here ran them for a few seasons in the alps too). If you do give them a go, I'd be happy to answer any questions you have along the way.

For whatever it's worth, I ran the same "The Ones" from 2011 as Nick did, and got 5 years of relatively hard use out of them, with one seal change on the rear caliper. I haven't owned the RO-R for that long (2nd season) so I can't give the same long term recommendation, but so far I'm quite happy. The Avid "Pro" bleedkit is handy, or alternatively there are copies on Aliexpress - the copy of the Pro kit works just as well as the real thing.

jimw said:

Huh? How so?

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The benefit of properly implemented heatsinks is primarily in glaze reduction.
As some people have alluded to, sintered pads have properties which make them superior in certain conditions (substantially greater longevity under bikepark/heavy use, markedly better wet weather performance), however because they wear slower they are more prone to glazing on the surface (a chemical change, not just a physical one) which reduces bite and ultimate braking force substantially. This means that the pads lose performance long before they wear out, and the heat damage is irreversible.

The metal pad connected directly to the alloy heatsink surface dissipates the heat very efficiently, thus improving this situation noticeably. On an organic pad - the pad material acts as an insulator so you get poor heat transfer into the heatsink, but there is also less necessity for the heatsink since the pad material wears at a much faster rate and thus inherently prevents glazing (thus heat related performance reduction) anyway. If they work for you then great - I certainly use them myself often too - but some people need sintered metal pads and I do think they are superior if you have proper heat management.

Anyway, there's nothing wrong with Shimano putting heatsinks on their organic pad, I'm sure there is still some small benefit and small heat transfer. However what is retarded is when companies like Swisstop put the heatsink ONLY on their organic pad and then sell sintered pads with no heatsink - to me that shows a distinct lack of understanding. Companies that offer a heatsink separate to the pad are also missing the point. Companies that put "heatsinks" on the caliper are also having a laugh (TRP, Hope, SRAM Guide: all guilty) because there are multiple layers of heat insulation before the caliper on MTB brakes and thus the caliper is unable to offer any useful heat dissipation. Shimano is the one company that applies heat management to brakes properly, shame they've dropped the ball in consistency and reliability.

Their pads though? Brilliant.

HAB said:

Unacceptable. I'd much rather just hold you personally responsible if it turns out that we have different personal preferences.

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Looks like I'm getting those SIXC cranks after all.

About pads with heatsink, did somebody try to adapt Shimano pads to caliper from other brands ?
It seems that it is possible to use Saint pads on Guide caliper after some grinding and redrilling of the hole. On the picture below I put Saint and Guide pads on top of each other

@HAB
What size rotors on your rig? Good success running 8"/7" rotors on my hardtail

Just spent waaaaaay too much time bleeding my 900 series xtrs.

After 2 syringes, it was running clean up to the lever. I filled the cup with clean fluid and let the system drain. I used almost 3 funnels of clean fluid while black crap drained out of the caliper.

Where does the dirty fluid hide??? Same place as the mystery bubbles, one would suppose...

But, as a bonus, I read that 3 business cards between the pads (with the funnel on), fills the system up nicely to reduce the throw.

Brakes feel better than they ever have... let's see if it lasts a whole ride.

I haz a skeptizizmz.

I have answers!

Unfortunately the shortened throw won't last long because overfilling the system just stresses the reservoir seals (which are designed to weep in the case of excess fluid) and they'll go back to whatever throw they had. The more technical explanation is that (before the excess leaks out) you also convert the open system brake into a pressurised / semi-closed system which is less than ideal. Gotta do what you gotta do though (I did the same in M810/M820 days).

The dirty fluid keeps coming because Shimano use a metal-on-metal interface in the master cylinder, where the piston is machined but the bore is cast. The bore wears faster being a softer material, which in turn causes localised loading on the piston which loses its anodizing. The now bare surfaces are free to oxidise, so the black stuff in the fluid is just aluminium oxide + wear particles. If you flush it out with clean fluid you'll notice it goes black again quite soon. Basically once this happens, it's time to replace the entire lever / MC assembly - Shimano brakes are disposable brakes (best power and performance while they work though!).

Avid/SRAM avoid this problem by using a polymer MC piston, but as many know, the polymer can swell as a result of long term glycol/polymer reaction which leaves you with a seized MC piston in the bore. Not sure if this is fixed in the latest iteration of Guides but there were some reports getting around. At least you can buy parts.

Hope avoid it by CNC machining (and anodizing) both parts so they have a much longer wear life, but the design is the same as Shimano otherwise. Again you can just replace the piston though, assuming the bore stays good ("hope"fully they used a weaker alloy for the piston).

Formula avoid it by using a hard-anodized piston in a cold forged + anodized MC body, along with a plastic glide bushing for the piston. This is on the T1, I haven't opened the new Racing levers yet, but after 5 years of use the T1 had zero wear on piston or bore and clear fluid. I wouldn't call them perfect all round, but definitely the nicest MC internal design I've seen. Being Italian though, they probably switched the new one to sausage sliding in a pizza bore with cheese for fluid or something, good luck @HAB.