Road bike disc brake upgrade

[Lozw86]

Hi there,

I have a road bike with Tiagra 10 speed and Decode R mechanical disk brakes. The brakes are poor, and having had the bike a year now, I’d like to upgrade them

I used to ride mountain bikes with Hope disc brakes and they were great so I have similar expectations here

I’m thinking Shimano 105 hydraulic disks

I’m not too clued up on road bike components. Will 105 brake levers include the gear shift and will they work with my Tiagra derailleur?

Are 105 hydraulic brakes a good choice? What are the alternatives? I don’t want anything more expensive

How much should I expect to pay a bike shop to change the brakes if I supply them? I assume the brakes will be cheaper ordered online. An hours labour?

Thanks

[David_M]

You could try some Tektro Hy/RD brakes - review - as an easier solution using the current levers / cable actuated.

I think that current 105 is 11-speed and therefore won't play nicely with Tiagra 10-speed. In fact, I think that most road hydro brake systems are 11-speed, but I could be wrong.

[Tidybeard]

If your rear mech is Tiagra 4700 then it has the same cable pull as the 11 speed Shimano shifters so will work. This is unique amongst the 10 speed/11 speed groupsets and I believe it's the only cross-compatibility.

I ran it the other way for a while - 10 speed Tiagra shifters on a 10 speed cassette with an R8000 11 speed Ultegra rear mech and it shifted perfectly. LBS confirmed it would work the other way round.

And yes, the 105 hydraulic shifters will include the gear change function. Huge difference between hydraulic and mechanical disk brakes, good move. Bike shop shouldn't take longer than an hour to set the whole thing up.

Edited by Tidybeard on Thursday 8th April 21:37

[Harpoon]

My winter road bike has Shimano RS405 brake levers / shifters and hydraulic callipers, with 10 speed (4700 series) Tiagra derailleurs. All works fine.

You need to watch out for the differences between flat mount and post mount, so might need adapters depending on disc rotor size.

There's a set on eBay for £225:

https://www.ebay.co.uk/itm/Shimano-ST-RS405-Shifte...

[David_M]

Tidybeard said:

If your rear mech is Tiagra 4700 then it has the same cable pull as the 11 speed Shimano shifters so will work. This is unique amongst the 10 speed/11 speed groupsets and I believe it's the only cross-compatibility.

Hooray for people that know more about Shimano that I do! Good luck.

[Tidybeard]

Harpoon said:

My winter road bike has Shimano RS405 brake levers / shifters and hydraulic callipers, with 10 speed (4700 series) Tiagra derailleurs. All works fine.

You need to watch out for the differences between flat mount and post mount, so might need adapters depending on disc rotor size.

There's a set on eBay for £225:

https://www.ebay.co.uk/itm/Shimano-ST-RS405-Shifte...

OP unless you really want 11 speed (if you do you'll need a new cassette too) then this is a good option and will be much cheaper than 105 shifters plus calipers plus cassette and will shift/brake pretty much as well.

[Harpoon]

Oh, and eBay code POCKET15 gets you 15% off, so even better at £192 (code expires 10th April).

I'd expect a full-time mechanic in a bike shop would take 3 to 4 hours to swap. They might need to untape / retape the bars if existing cables run underneath the bar tape. Also might take longer if the cable routing is a PITA.

[Master Bean]

https://www.tredz.co.uk/.Shimano-Tiagra-ST-4720-Hy...

You can get these Tiagra levers which look the same as the 105/Ultegra/Dura Ace ones.

[Maximus_Meridius101]

Master Bean said:

https://www.tredz.co.uk/.Shimano-Tiagra-ST-4720-Hy...

You can get these Tiagra levers which look the same as the 105/Ultegra/Dura Ace ones.

They look the same, but they don’t feel the same.

[Gin and Ultrasonic]

Maximus_Meridius101 said:

Master Bean said:

https://www.tredz.co.uk/.Shimano-Tiagra-ST-4720-Hy...

You can get these Tiagra levers which look the same as the 105/Ultegra/Dura Ace ones.

They look the same, but they don’t feel the same.

I've had hydraulic Tiagra, 105 and Ultegra DI2, and the braking on them all seems about the same in terms of power / modulation. The Ultegra shifters are by far the best looking and most comfortable for riding on the hoods, but I didn't notice much difference between the Tiagra (from 2020) and 105 (from approx 2016). I personally find the reach on the Tiagra levers better to use while on the drops than the Ultegra ones (and I have adjusted them).

I'd guess any hydraulic system would be way ahead of mechanical in terms of maintenance (self-adjusting) and power / modulation.

Another thing to consider is cable routing - my bikes with hydraulic have had internal cable routing and / or cables guides. The hydraulic cables look like they are thicker than standard cables to me, so they might need to be fixed with different guides - not sure if this is true or not - I'm not a mechanic!