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Need to find “post mount” disc calipers for a cyclocross frame where I’ll running…

Old 11-25-23, 10:57 AM
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Need to find “post mount” disc calipers for a cyclocross frame where I’ll running…

…Shimano Ultegra 8120 road disc brifters. Could someone point me to a Hope, Magura, Shimano or Tektro caliper that takes Shimano spec mineral oil & has the correct modulation for Shimano disc road (160 mm rotors)?
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Old 11-25-23, 02:37 PM
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Ebay.com

search: Bicycle Post mount disc brake calipers.
Read the descriptions of the calipers in the listings.
if they don't specify fluid types, either ask the seller for more info, or move on to another listing.
i've had good results with Shimano calipers matching their levers.

hint: the magura calipers specify a mineral oil with dye added in an attempt to make it seem special and more exclusive.... etc.

Last edited by maddog34; 11-25-23 at 02:43 PM.
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Old 11-25-23, 03:21 PM
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Originally Posted by maddog34
Ebay.com

search: Bicycle Post mount disc brake calipers.
Read the descriptions of the calipers in the listings.
if they don't specify fluid types, either ask the seller for more info, or move on to another listing.
i've had good results with Shimano calipers matching their levers.

hint: the magura calipers specify a mineral oil with dye added in an attempt to make it seem special and more exclusive.... etc.
This isn't an answer and I wish you wouldn't clot threads with non-advice. It is so incredibly tiresome to have a mechanic dispensing rude and bad advice in equal measure.

As you should know, Shimano has two hydraulic formats that pump different amounts of fluid at different pressures through different diameter lines. An ebay seller is not going to be able to correctly divine what will work properly. I don't know why you think giving bad advice with regards to life-or-death equipment is funny, but it is definitely not.


masi61 , because of the issues mentioned, there may not be a good candidate for an aftermarket caliper. Not only does it need the right fluid pumped in the right volume, it needs a barb and olive system compatible with kind of lines the levers designate. I took a brief look, and there doesn't seem to be any official specs or forum chatter about such combinations. Is there a good reason to not use Shimano calipers with whatever mount adapters?
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Old 11-25-23, 05:10 PM
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Originally Posted by Kontact
This isn't an answer and I wish you wouldn't clot threads with non-advice. It is so incredibly tiresome to have a mechanic dispensing rude and bad advice in equal measure.

As you should know, Shimano has two hydraulic formats that pump different amounts of fluid at different pressures through different diameter lines. An ebay seller is not going to be able to correctly divine what will work properly. I don't know why you think giving bad advice with regards to life-or-death equipment is funny, but it is definitely not.


masi61 , because of the issues mentioned, there may not be a good candidate for an aftermarket caliper. Not only does it need the right fluid pumped in the right volume, it needs a barb and olive system compatible with kind of lines the levers designate. I took a brief look, and there doesn't seem to be any official specs or forum chatter about such combinations. Is there a good reason to not use Shimano calipers with whatever mount adapters?
You gave the same advice i did, and also stated that you don't know what you say i don't know.
Summation: use the shimano parts that are specific to the series group involved....
and masi61 only said he was having trouble FINDING post mount calipers that would work with his shimano master cylinders... and the post laid here for two days, un-answered.

i sent him to an outlet with ALL the choices he listed, then recommended asking pertinent questions, and moving on if the sellers couldn't answer the questions to his satisfaction

You then insulted my abilities, and a few other things.. but only after i'd posted to the thread, and you'd ran online searches for ways to insult someone.
this is exactly why i've once again placed you on my "Ignore" list. .

Here's hoping Masi61 can find the shimano calipers that he needs for his repair or project.
smh.
if you truly wanted to help, you would have found what masi61 needed, posted that info, and not been your usual insultive self.
and you also would have addressed the mineral oil question.

bye bye.
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Old 11-25-23, 06:09 PM
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Originally Posted by masi61
…Shimano Ultegra 8120 road disc brifters. Could someone point me to a Hope, Magura, Shimano or Tektro caliper that takes Shimano spec mineral oil & has the correct modulation for Shimano disc road (160 mm rotors)?
one option :

Shimano BR-RS785 brake calipers

they are Ultegra level - post mount - and compatible with the better quality / narrow track Shimano 160 mm rotors

https://bike.shimano.com/en-EU/produ.../BR-RS785.html

installed them on one of my bikes with SM-RT86 (IceTech) 160 mm rotors and J05A-RF (finned) brake pads (pictures above)

Last edited by t2p; 11-25-23 at 06:15 PM.
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Old 11-25-23, 06:32 PM
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Originally Posted by masi61
…Shimano Ultegra 8120 road disc brifters. Could someone point me to a Hope, Magura, Shimano or Tektro caliper that takes Shimano spec mineral oil & has the correct modulation for Shimano disc road (160 mm rotors)?
My first-gen Ultegra came with relabeled XT post mount calipers (i.e., Shimano BR-RS785 brake calipers as mentioned above). In fact, I had to replace one with an XT label. The only practical difference is that the bolt that holds the brake pads in place is 3mm hex in the XT instead of a slot bolt for the Ultegra calipers.

I've also installed a set of XT calipers with my GRX brakes. Works fine.
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Old 11-25-23, 07:55 PM
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Originally Posted by maddog34
You gave the same advice i did, and also stated that you don't know what you say i don't know.
Summation: use the shimano parts that are specific to the series group involved....
and masi61 only said he was having trouble FINDING post mount calipers that would work with his shimano master cylinders... and the post laid here for two days, un-answered.

i sent him to an outlet with ALL the choices he listed, then recommended asking pertinent questions, and moving on if the sellers couldn't answer the questions to his satisfaction

You then insulted my abilities, and a few other things.. but only after i'd posted to the thread, and you'd ran online searches for ways to insult someone.
this is exactly why i've once again placed you on my "Ignore" list. .

Here's hoping Masi61 can find the shimano calipers that he needs for his repair or project.
smh.
if you truly wanted to help, you would have found what masi61 needed, posted that info, and not been your usual insultive self.
and you also would have addressed the mineral oil question.

bye bye.
Telling someone to go look on ebay for other mineral oil calipers when you are aware there is a lot more to compatibility than that is not "asking pertinent questions". A pertinent question would need to reference the specifics I mentioned.
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Old 11-25-23, 07:57 PM
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Originally Posted by Polaris OBark
My first-gen Ultegra came with relabeled XT post mount calipers (i.e., Shimano BR-RS785 brake calipers as mentioned above). In fact, I had to replace one with an XT label. The only practical difference is that the bolt that holds the brake pads in place is 3mm hex in the XT instead of a slot bolt for the Ultegra calipers.

I've also installed a set of XT calipers with my GRX brakes. Works fine.
Earlier Shimano road hydro used MTB format specfics and BH59 hoses. Current road stuff use BH90 hoses because the differences.
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Old 11-25-23, 08:13 PM
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Originally Posted by maddog34
Ebay.com

search: Bicycle Post mount disc brake calipers.
Read the descriptions of the calipers in the listings.
if they don't specify fluid types, either ask the seller for more info, or move on to another listing.
i've had good results with Shimano calipers matching their levers.

hint: the magura calipers specify a mineral oil with dye added in an attempt to make it seem special and more exclusive.... etc.
Not the greatest advice. You could do better than go to a website and buy whatever.

Magura uses Royal Blood and like all mineral oil I have seen for brakes has color added but it doesn't really change the price most of the mineral oil is around the same price within a dollar or two generally which isn't really significant. Shimano is red. Tektro is also red, Finish Line is green as is Maxima and Magura and Campagnolo are blue. RGB a very common color model it has no bearing on anything in this case other than what the manufacturer chose.


Getting to the OPs original question Hope makes a lovely 4 pot mineral oil brake called the RX4+ it can be distinguished from the M on the outer cap. https://www.hopetech.com/products/br...x/rx4-caliper/ They are compatible with R8000 series and look really nice especially the anodized ones. I had a former co-worker running them and he loved them and they looked a treat.

People do mix Shimano and Magura and call it Shigura. I haven't seen it really with road but not to say it doesn't exist I just haven't personally seen it. I think with the correct fittings I think it would work fine.

Technically Shimano MTB brakes are a different "cable pull" in a way (obviously no cables) but I have seen people make it work. However if you want to actually use Shimano calipers I would look at BR-RS785: https://bike.shimano.com/en-EU/produ.../BR-RS785.html I am unsure if they are still producing them but it is possible your local shop might have them or you might find another brick and mortar with a set.

You could also run these and run flat mount:
https://www.assolutions.ca/shop/adap...ith-160-rotor/
https://www.assolutions.ca/shop/adap...ith-160-rotor/
https://www.assolutions.ca/shop/adap...ith-140-rotor/

I probably wouldn't run Tektro or other stuff but you could probably get some of that stuff to work.
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Old 11-25-23, 08:17 PM
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Originally Posted by veganbikes
Not the greatest advice. You could do better than go to a website and buy whatever.

Magura uses Royal Blood and like all mineral oil I have seen for brakes has color added but it doesn't really change the price most of the mineral oil is around the same price within a dollar or two generally which isn't really significant. Shimano is red. Tektro is also red, Finish Line is green as is Maxima and Magura and Campagnolo are blue. RGB a very common color model it has no bearing on anything in this case other than what the manufacturer chose.


Getting to the OPs original question Hope makes a lovely 4 pot mineral oil brake called the RX4+ it can be distinguished from the M on the outer cap. https://www.hopetech.com/products/br...x/rx4-caliper/ They are compatible with R8000 series and look really nice especially the anodized ones. I had a former co-worker running them and he loved them and they looked a treat.

People do mix Shimano and Magura and call it Shigura. I haven't seen it really with road but not to say it doesn't exist I just haven't personally seen it. I think with the correct fittings I think it would work fine.

Technically Shimano MTB brakes are a different "cable pull" in a way (obviously no cables) but I have seen people make it work. However if you want to actually use Shimano calipers I would look at BR-RS785: https://bike.shimano.com/en-EU/produ.../BR-RS785.html I am unsure if they are still producing them but it is possible your local shop might have them or you might find another brick and mortar with a set.

You could also run these and run flat mount:
https://www.assolutions.ca/shop/adap...ith-160-rotor/
https://www.assolutions.ca/shop/adap...ith-160-rotor/
https://www.assolutions.ca/shop/adap...ith-140-rotor/

I probably wouldn't run Tektro or other stuff but you could probably get some of that stuff to work.
Fantastic post! I was unable to find any reference to Shimano road compatible calipers - cool that Hope does that.
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Old 11-25-23, 08:19 PM
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If you have flat mount calipers with your levers already, go with these https://www.assolutions.ca/flat-moun...adapter-guide/ I used them to fit flat mount hydraulics on the wife's C-dale Caadx.
Hope https://www.hopetech.com/products/br...x/rx4-caliper/ claims their lever is compatible with 8100 series levers and 8000 series, while shimano's compatibility chart doesn't show the levers being compatible with the same calipers, which can often be shimano being picky about how they want things to work. Hope may use different hoses based on the lever or may just find the difference to be small enough that it doesn't matter. Shimano doesn't list any post mount compatible calipers that will work with your levers, I would be suspicious that a 2 piston caliper like Deore's will still work, but at the upper levels MTB has gone 4 piston and road hasn't making them incompatible.
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Old 11-25-23, 08:41 PM
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Originally Posted by Kontact
Fantastic post! I was unable to find any reference to Shimano road compatible calipers - cool that Hope does that.
Thanks, they were sort of like the longer reach road rim calipers back in the day sort of under the radar but Ultegra level. Road post mount I don't think quite took off at the time as road hydro discs were new so it sort of went more to flat mount.

Hope does some really neat stuff sort of the UK version of Paul Component Engineering in sense.
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Old 11-26-23, 08:13 AM
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For what it's worth I run Grx shifters with the cheapest Shimano Brake Calliper, Bl-mt200 . No issues brake feel and stopping power are as good as my Ultegra disc brakes bike.
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Old 11-26-23, 09:02 AM
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I was under the impression that as long as the hose type was the same, bh90 or bh59 or whatever and you used mineral oil then you were good to go. Simply a matter of matching the barb, banjos & olives at the right end of the system that that component expects.

I have a mix/match of Shimano and Tektro levers and calipers on several bikes. Works fine. Tektro levers Tektro hose, Shimano caliper, works fine too.

As to 2 pot vs 4 pot...I don't know. It would stand to reason that 4 pot would have 2x the capacity at the same lever stroke (MTN/MTN) or 2x the lever stroke necessary in a mix/match (road/MTN), or half the power (MTN/road) but only if the piston size were held constant. The only reason I can see to do that is to restore the cable like road/MTN incompatibility. Because...Shimano.

The piston size however, is not held constant. 4 pot MTN pistons are smaller. So really, it would be useful if somebody with a 4 pot caliper took a measuring caliper and a bit of geometry to derive the total piston surface area. If equal, then good to go from a functional equivalency perspective since the same amount of fluid is being displaced. Failing that, a person with components on hand could hillbilly together an actual experiment to determine the functional answer with added cost/failure risk.
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Old 11-26-23, 10:21 AM
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Originally Posted by veganbikes
You could also run these and run flat mount:
https://www.assolutions.ca/shop/adap...ith-160-rotor/
https://www.assolutions.ca/shop/adap...ith-160-rotor/
https://www.assolutions.ca/shop/adap...ith-140-rotor/

I probably wouldn't run Tektro or other stuff but you could probably get some of that stuff to work.
I have experience with the AS. Solutions mount adapters and really like them. It's very important to print the template out to make sure they'll work for the frameset in question though! I had to sand a little on my adapters to get them to work. (160PM to 160FM)

If you're interested in the +20mm adapter, it looks like there are a few other options that may be a little less expensive...
https://www.wolftoothcomponents.com/...-brake-adapter
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Old 11-26-23, 02:07 PM
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Originally Posted by base2
I was under the impression that as long as the hose type was the same, bh90 or bh59 or whatever and you used mineral oil then you were good to go. Simply a matter of matching the barb, banjos & olives at the right end of the system that that component expects.

.
you were / are correct

there is no technical difference in the internals of Shimano hydraulic brakes supplied with BH59 and BH90 brake hose

BH90 is advised - possibly / theoretically stiffer due to smaller internal bore (?) - but you might not feel the difference

I purchased a new set of BH90 brake hoses when I installed new XT levers (BL-M8000 brake levers) and Ultegra calipers (BR-RS785 brake calipers) - but was lazy and just used the old / existing BH59 brake hoses and the brakes are great - no difference compared to another bike with XT levers and calipers and the recommended / proper BH90 brake hose

Last edited by t2p; 11-26-23 at 02:10 PM.
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Old 11-26-23, 03:49 PM
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I would use the levers and calipers that are meant for one another and use an adaptor to fit into the fork/frame as needed.
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Old 11-30-23, 05:07 PM
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I thought of using the Universal Hope braided stainless brake hose then putting a Hope barb/ferrule on one end and a Shimano barb/ferrule on the other end.
I’m going to buy the Hope RX4+ post mount calipers in black from Merlin.UK. I figure they should work well with the 8020 Ultegra hydro 11 speed mechanical shift integrated levers.
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Old 12-02-23, 07:02 AM
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Originally Posted by tFUnK
I would use the levers and calipers that are meant for one another and use an adaptor to fit into the fork/frame as needed.
This might be the safest way to go. Those Wolf Tooth adapters look like high quality. Price wise, a set of Ultegra 8070 disc calipers combined with the Wolf Tooth Brackets makes me again consider the Hope RX4+ post mounts though since no adapter bracket would be required.
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