Switching to hydraulic from mechanical disks

[sixtoes]

Through a combination of corrosion and crash damage the shifters and calipers on my Giant Defy are past their best and could do with replacing. Despite using compressionless housing, decent pads, and constantly fettling the calipers they’ve never felt as good as the entry level Shimano hydraulics on my MTB. So given I need to replace nearly all the parts anyway I'm planning to swap the mechanical system to hydraulics.

For the shifters I’m planning on getting a set of decent second hand ST-R7020 from eBay.

The frame has post mountings so I’m planning on getting MTB calipers as there is more choice and they are cheaper. I was planning on BR-MT400 calipers - which brings us to my questions:.

1. Apparently the R7020s use BH90 hose but the MT400s use BH59 hose. Am I right that it doesn’t really matter which hose I use as long as I use the right inserts - which would be the silver one at both ends with BH90, or the gold one at both ends with BH59?

Or should I be using calipers and shifters that use matching hose types, meaning I should go for something like BR‑M615 calipers with the R7020s?

2. I know I’ll need to buy a bleed kit to set it all up, am I right that this would give me everything I need?: https://epicbleedsolutions.com/products ... -bleed-kit

3. Is there anything else I need to know or think about?

Any advice is very welcome, and thanks in advance!

[thelawnet]

I have a list of the Shimano hydraulic discs here:

https://docs.google.com/spreadsheets/u/ ... HR29c/edit

Essentially you can match any lever with any caliper.

The MT400s are low-grade and no different from MT200s as best I can tell, so you might as well get those.

Basically:

BH59 and BH90 are work just fine with any brakes, but BH90 has a narrower inner bore (so you need a different insert, which is supplied with the brake). Originally BH59 was used for road brakes because Shimano thought 'being responsive' was bad, but then they realised it wasn't, and now they mostly use BH90 because it's 'more premium', and they charge an arm and a leg for their road stuff because they can.

The levers have straight connections (they did use banjo fittings a long time ago, but no longer), and banjo fittings are common for mountain bike brakes as it might reduce heat by some immeasurable amount or some such. But this is 'not road', so they don't have banjo fittings on their road calipers (except for the R785, which was just a relabelled SLX/XT caliper).

Anyway, Shimano will charge you a stupid price for hoses. A bog-standard BH59 is £40 for a pair from Wiggle.

A complete MT200 brake is £20 (for one) from Decathlon, so you get a free brake and lever for the price of the hose.

BH90 is even more stupid price (£60), and you have to be a bit daft to pay it.


Shimano have a thing called J-Kit, which they don't discuss on their public site, because it's a way to save money for assemblers by making your bike a gram or two heavier (which they omit from their specs, duh)

There's a video on their bike shop website (which you can sign up to without any special details, just enter a random bike shop)

https://www.shimano-tec.com/login/index.php

Anyway, this will have an extra length of hose dangling out of the road lever. But you can use either j-kit (which is a hose pre-filled with oil & a cap on each end) or non j-kit hose on any bike, so it doesn't matter too much, it's just an extra (unnecessary) connector (also the hose insert is different).

Decathlon have a complete M6000 front brake for £40. This is upgraded vs MT200/MT400 as you get BH90 and a better choice of pads. For some reason the rear is £60. (M6100 is the same thing)

You can find possibly find the T6000 brake (which comes with the same caliper but a slightly less sophisticated lever) for around £50 as well.

The MT420 brakeset will come with BH90 hose and runs about £100 for a pair. It's also a 4-caliper brake, which should be gross overkill.

But basically the cheapest route seems to be R7020 levers (£whatever) + MT200 brakes (£40 including lever + hose).

Also you could consider the ST-RX600 shifters, which are very similar albeit 'gravel', whatever that means.

I would not necessarily recommend a bleed kit, also ignore all the videos & generic instructions online as Shimano changes things around a lot, so that's just a waste of your time to look at them.

Generally you will need a set of allen keys, possibly a 7mm and/or 8mm open and/or closed spanner, which you might have already.

Then the new brakes should be supplied with a bleed block, which will vary for your calipers (so I don't think that one will work for a MTB caliper). So you likely don't need to buy one.

It might not be necessary to cut the hose, as some places supply shorter hose. But if you do, a cheap hose cutter is about £4.

This all that's really needed for bleeding

https://www.ebay.co.uk/itm/Bicycle-Hydr ... 3715659073

The Shimano brake oil is obscenely priced - they charge about £20 a litre which is not so bad, but smaller quantities are more like £100/litre.

[sixtoes]

That's amazing, thanks so much!

I've got all the non brake specific tools, so if I get:

R7020 shifters (I'll probably get R7025 as they are a bit smaller which suits me)
MT200 set (front and rear, about £40)
eBay bleed kit (about £4)
BH59 inserts for the shifter ends of the hoses (about £3 each)
Tube cutting tool (about £4)

It looks like I'm good to go. Thanks again!

[thelawnet]

I don't think you necessarily need a new insert, I've had brakes supplied cut short and others supplied with longer hoses and a spare olive and insert.

If no olive and insert is supplied then you can maybe cut them and reuse them, the insert should be recoverable from the hose if you cut it up, but perhaps the olive is deformed by fitting. I imagine it will still be ok though.

[Brucey]

check that the appropriate track width of the discs is a match between the old and new calipers.

cheers

[Redvee]

My day to day set-up is R7020 and M7000 callipers with BH90 hoses with no issues in the time I've been running that set-up.

If no olive and insert is supplied then you can maybe cut them and reuse them, the insert should be recoverable from the hose if you cut it up, but perhaps the olive is deformed by fitting. I imagine it will still be ok though.

You will need a new olive and insert each time you change the hose, the olive gets compressed slightly and deformed in the lever, you can buy packets of olives and inserts for a few quid on Amazon/Ebay.

If buying the levers pre-owned you might get away with not needing to buy a BH90 flange nut which connects the hose to the levers. You'll have the insert then olive then BH90 flange nut with 8mm flats at the end of the hose going into the brake lever. Looking at images of the callipers you'll just need straight hose with no special connector at the calliper end, some callipers need a banjo connector.
I use the bleed kit from Epic Solutions and bought the Shimano bleed funnel that comes with the adapter for road levers. Another tool you'll need is a 2mm allen key for the bleedport cover.
There are plenty of how-to videos on YouTube but I prefer this guy's channle and videos

[youtube]NhTGk6b-E-k[/youtube]

There is also some reach adjustment on R7020 levers

[youtube]CbAHYd6tZj0[/youtube]

[sixtoes]

Fantastic, thank you for posting this. I'll look into getting flange nuts and also have a watch of those videos.

[freeflow]

He doesn't use the hose clamp, which is the black object on the tube. You slide this forward towards the caliper until it clicks into place at the caliper end. This stops the hose blowing off due to too much pressure in the hose when pumping the mineral through the caliper.