Shimano road discs ...
 

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[Closed] Shimano road discs - fitting a caliper from a MTB groupset?

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Has anyone tried fitting one of Shimano's MTB post mount calipers to their hydraulic disc road STI levers? Say RS785 or the BR505?

It looks like £40 - £50 for a new post mount road caliper but I can see some basic Shimano hydraulic MTB calipers for £20. Would it make much of a difference? I.e. anything to affect lever throw because the caliper pistons are different sizes etc

I'm trying to eliminate a squeal and after pads/discs having read up on here, it sounds like a new caliper might be needed?


 
Posted : 01/06/2020 9:43 pm
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Yes, they work fine


 
Posted : 01/06/2020 9:47 pm
 cp
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I've got xt 785 calipers on 505 levers and also m615 calipers on r8020 levers..

Work absolutely fine, no issue with pad wear compensation or anything really, they just work


 
Posted : 01/06/2020 9:47 pm
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I used R685 and R785 levers with m9120 callipers for years without problems. You just need to make sure that both ends are using the same inserts (BH59 or BH90)


 
Posted : 01/06/2020 9:49 pm
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Thanks guys.

When you say inserts Daffy, is it easy to tell the difference?


 
Posted : 02/06/2020 8:20 am
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So unless I'm changing the hose, the insert will remain the same at both ends.... Or do I potentially need to change both inserts depending on which caliper I use?


 
Posted : 02/06/2020 8:24 am
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Hope do a nice set of aftermarket calipers that go on . They are even mineral compatible. Rx4-sh

While would look out of place that's my plan when the Shimano ultegra calipers enevitably shit the bed. Although touch wood they are proving more reliable than their MTB counterparts


 
Posted : 02/06/2020 8:31 am
 cp
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So unless I’m changing the hose, the insert will remain the same at both ends…. Or do I potentially need to change both inserts depending on which caliper I use?

Yes insert is specific to the hose not the (Shimano) caliper or lever.


 
Posted : 02/06/2020 8:43 am
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Out of interest has anyone tried Magura callipers with Shimano shifters have RS785s, have tried Saint levers to MT5s no issues, so wondered if would work with the road stuff


 
Posted : 03/06/2020 9:04 am
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I couldn’t find any flat mount RX4 when I looked a few months back. I too have wondered about the cross-compatibility of mtb and road as I fancied a pair of four piston Calipers for the front.


 
Posted : 03/06/2020 9:59 am
 pdw
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Can confirm that it works fine. I'm running an XT caliper with a GRX lever. If you get a caliper with a banjo fitting, you'll also need a new hose.


 
Posted : 03/06/2020 10:06 am
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someone posted this link a couple of weeks ago kept a copy as I have a PM gravel frame that will probably go down the GRX lever MTB caliper route on....this chart is Road/Gravel but gives the hose type which I believe is the issue

https://productinfo.shimano.com/#/com?q=st-rx&cid=C-453&acid=C-499


 
Posted : 03/06/2020 11:49 am

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