Shimano STi Hydros

sniper68

I have fitted Shimano Di2 ST-R785+ BR-RS805 hydraulic brakes to my new build but am not impressed at all by them.OK they work perfectly but there is just far too much lever travel for my liking.I've bled them,no joy so I took them to a LBS who bled them and basically said that's as good as they get!?!
I've had hydros on MTBs for almost 2 decades,Hope,Formula,Avid but never Shimano.I've always had them set up so they start to bite after about 5-10mm of lever travel(I also have this set up on my road bike with rim brakes)but with these the brakes don't start to work until the lever has travelled roughly half way.If I wind the levers in slightly the levers are almost touching the bars before they work.
Surely this isn't how road STi hydraulics are

Am I missing something?

pilot_pete

You have followed the Shimano dealer manual guidance to set them up and adjust free float and lever reach yes? Page 47 here https://si.shimano.com/pdfs/dm/DM-BR0004-05-ENG.pdf I’ve got these and they are fine. I’ve also got Dura Ace 9170 which bite a bit earlier....

PP

sniper68

pilot_pete said:

You have followed the Shimano dealer manual guidance to set them up and adjust free float and lever reach yes? Page 47 here https://si.shimano.com/pdfs/dm/DM-BR0004-05-ENG.pdf I’ve got these and they are fine. I’ve also got Dura Ace 9170 which bite a bit earlier....

PP

Yes all that has been done,done again and done again.They've now been to another LBS and I've begrudgingly paid them to install new hoses/olives/barbs.They bled them and......no better.
From talking to LBS mechanics and others with Shimano Hydraulic STis the consensus seems to be that it's as good as they get!

A few people have solved the issue by installing Hope RX4 Calipers.That will be my next move.I tried a friends levers with RX4s fitted and the difference is like night and day.
Another couple of hundred quid to get good brakes will be worth it.

step83

Wondering if the is similar to my issue, bike stored level, leave it for a day an the rear brake goes long till pumped then comes back, that an the pads squeal like hell all the time.

pilot_pete

step83 said:

Wondering if the is similar to my issue, bike stored level, leave it for a day an the rear brake goes long till pumped then comes back, that an the pads squeal like hell all the time.

You have air in the system then. The rear brake is harder to bleed as the hose is much longer. Have you tried bleeding it with the front wheel raised up higher than the back? And bleed from both ends to remove all the air from the reservoir and the caliper?

If your brakes squeal all the time it is likely that the pads are contaminated. I have 3x disc brake bikes and the only squeal I get is on cool, moist air days.

PP

thistle_

I've got older, non di2 brakes and they're fine.
There's a bit of lever travel initially but then they bike and there's plenty more travel left.
When bleeding the brakes are you using a bleed block that pushes the piston all the way back? You could use a thinner block and get some more fluid in to reduce the travel...

fenix

Can't you test another bike that has them to see if it's just your bike or just that you don't like the way they work?

step83

pilot_pete said:

step83 said:

Wondering if the is similar to my issue, bike stored level, leave it for a day an the rear brake goes long till pumped then comes back, that an the pads squeal like hell all the time.

You have air in the system then. The rear brake is harder to bleed as the hose is much longer. Have you tried bleeding it with the front wheel raised up higher than the back? And bleed from both ends to remove all the air from the reservoir and the caliper?

If your brakes squeal all the time it is likely that the pads are contaminated. I have 3x disc brake bikes and the only squeal I get is on cool, moist air days.

PP

This is the annoying thing, I bled them fully, full syringe of oil pushed through to the top, pumped the handle bike at funky angles etc stops on a dime that day, next day its crap again. an everything is tight no visible leaks
Probably right on the pads, I took them off an sanded off the top layer to see, cleaned the discs with IPA, nope still squeak, I'll see about some new ones if not I'll just get some small boat anchors to toss out when I need to stop.

sniper68

thistle_(mbnw) said:

I've got older, non di2 brakes and they're fine.
There's a bit of lever travel initially but then they bike and there's plenty more travel left.
When bleeding the brakes are you using a bleed block that pushes the piston all the way back? You could use a thinner block and get some more fluid in to reduce the travel...

I've done that and I've also tried the "Epic Bleed 5-min bleed hack" where you just bleed the lever leaving the wheel and pads in.Two LBS have done this too.

fenix said:

Can't you test another bike that has them to see if it's just your bike or just that you don't like the way they work?

I've tried a couple in the LBS and they are very similar to mine.I've tried a SRAM and they feel much more like I'm aiming at.

There's definitely no air in the system and the brakes are excellent apart from the lever travel/stroke issue.

fenix

If all the other bikes with it feel similar then I'd think it's just not to your taste.

If it were me I'd give it a while longer - clearly loaads of people can get on with it.

sniper68

fenix said:

If all the other bikes with it feel similar then I'd think it's just not to your taste.
If it were me I'd give it a while longer - clearly loaads of people can get on with it.

So loaads clearly get on with it so I should too?
Maybe loaaads haven't experienced decent hydraulics on a bike?
I have.These are clearly not up to the job they are aimed at.Why give something that is poor longer?Makes no sense.
I'll give the RX4 calipers a try and if that doesn't work then I'll ditch the Di2 completely(shame as the gears are faultless) and go for ETAP.The SRAM hydraulics I've compared seem to be much better.Strange really as Avid(SRAM) were generally cr@p MTB brakes!

acuna_read

Had Shimano 105 hydraulic with RX4 calipers. Instant bite and good feedback.

thecycleclinic

The brakes as they are are up to the job of stopping you. Comparing mtb brake with a short lever to road bikes levers with a longer lever is not fair as the longer lever moves move at the tip without moving more. Also by using the rx4 calipers you get a closer bite point because the calipers displaced volume is smaller. I.e less braking force.

So your want means less braking force. Great choice.

fenix

Sniper -you missed the point. If it's not for you it's not for you but there is nothing wrong with the system. Calm down.

thecycleclinic

the op also needs to understand the mechanics of bydraulic brakes.

There is not a hydraulic disc brake on the market than can give that instant lever feel the op wants.

In fact that instant bite is the problem. With rim brakes shimamo, sram and campagnolo recommend the pads are 1.5mm to 2mm from the rim because wait for it, you get peak mechanical leverage when the pad contacts the rim. So by wanting instant bite you decrease the effectiveness of the brake.


The same goes for the disc brakes as instant bite mean rotor rub and less braking force as a small slave cylinder has to be used.

Hard instant brakes on bicycles are a sign of a poor setup or design as its one with lower mechanical advantage.

Admittedly though the shimano r795, rs 685 and r505 brakes are difficult to set up with the bite point half way through the lever travel. The newer brakes are better in this regards.

First.Aspect

The solution is rim brakes.

I've just been bombing around Dartmoor on a 15 year old 6-13 and the brakes are better than my R3 (ultegra hydro, set up fine, so, meh).

It also handles better and looks better. And has better balance between front and rear forks. Doesn't need an over stiff front fork to handle the disc brakes I guess.

Modern bike design irritates the hell out of me.

step83

thecycleclinic said:

the op also needs to understand the mechanics of bydraulic brakes.

Admittedly though the shimano r795, rs 685 and r505 brakes are difficult to set up with the bite point half way through the lever travel. The newer brakes are better in this regards.

Certainly agree they are hard to setup. My front R505 is lovely (pads a bit squeaky) rear is terrible air as said before is sneaking in somewhere an as a result poor initial bite then after pumping you get too much bite an the pad spacing is off.
I have a Haynes pad alignment tool, basically a pair of feeler gauges on a bit of metal the width of a brake disc. can set it up an spacing is perfect. go out, fronts still teh same, rears are a mess. lots of work to do still.

Ben6899

First.Aspect said:

The solution is rim brakes.

I've just been bombing around Dartmoor on a 15 year old 6-13 and the brakes are better than my R3 (ultegra hydro, set up fine, so, meh).

It also handles better and looks better. And has better balance between front and rear forks. Doesn't need an over stiff front fork to handle the disc brakes I guess.

Modern bike design irritates the hell out of me.

I'd like to see a photo of the old bike.

First.Aspect

Ben6899 said:

First.Aspect said:

The solution is rim brakes.

I've just been bombing around Dartmoor on a 15 year old 6-13 and the brakes are better than my R3 (ultegra hydro, set up fine, so, meh).

It also handles better and looks better. And has better balance between front and rear forks. Doesn't need an over stiff front fork to handle the disc brakes I guess.

Modern bike design irritates the hell out of me.

I'd like to see a photo of the old bike.

Not the actual bike but pretty much exactly this

https://pezcyclingnews.com/amp/technspec/cannondale-six13-spied-tried/

So if you happen to see one on Dartmoor this week say hello as you pass me. If I don't reply it is because I'm close to expiring.

Ben6899

First.Aspect said:

Ben6899 said:

First.Aspect said:

The solution is rim brakes.

I've just been bombing around Dartmoor on a 15 year old 6-13 and the brakes are better than my R3 (ultegra hydro, set up fine, so, meh).

It also handles better and looks better. And has better balance between front and rear forks. Doesn't need an over stiff front fork to handle the disc brakes I guess.

Modern bike design irritates the hell out of me.

I'd like to see a photo of the old bike.

Not the actual bike but pretty much exactly this

https://pezcyclingnews.com/amp/technspec/cannondale-six13-spied-tried/

So if you happen to see one on Dartmoor this week say hello as you pass me. If I don't reply it is because I'm close to expiring.

Very nice!

And if someone does wave to you on Dartmoor, this week, it wasn't me. Regrettably.

pilot_pete

step83 said:

thecycleclinic said:

the op also needs to understand the mechanics of bydraulic brakes.

Admittedly though the shimano r795, rs 685 and r505 brakes are difficult to set up with the bite point half way through the lever travel. The newer brakes are better in this regards.

Certainly agree they are hard to setup. My front R505 is lovely (pads a bit squeaky) rear is terrible air as said before is sneaking in somewhere an as a result poor initial bite then after pumping you get too much bite an the pad spacing is off.
I have a Haynes pad alignment tool, basically a pair of feeler gauges on a bit of metal the width of a brake disc. can set it up an spacing is perfect. go out, fronts still teh same, rears are a mess. lots of work to do still.

You are bleeding it properly aren’t you? Forcing in fluid from the caliper up to the lever with the port cap removed and a cup/ syringe mounted in the lever port? Once clear fluid with no bubbles emerge, close the caliper bleed nipple and then add a tube into a reservoir/ cup/ bag.

Now force clean fluid in from the lever port with the caliper bleed nipple open to expel any air from the caliper. If this doesn’t sort it, you may need to try raising the front of the bike up higher to get an ‘uphill’ run all the way from rear caliper to lever (which includes the bit from the caliper around the bottom bracket.

This can help, especially with a tiny pocket of air in the caliper.

This is why a front disc brake is so easy to bleed in comparison as the hose is virtually vertical from the caliper to the lever.

PP

david37

First.Aspect said:

Ben6899 said:

First.Aspect said:

The solution is rim brakes.

I've just been bombing around Dartmoor on a 15 year old 6-13 and the brakes are better than my R3 (ultegra hydro, set up fine, so, meh).

It also handles better and looks better. And has better balance between front and rear forks. Doesn't need an over stiff front fork to handle the disc brakes I guess.

Modern bike design irritates the hell out of me.

I'd like to see a photo of the old bike.

Not the actual bike but pretty much exactly this

https://pezcyclingnews.com/amp/technspec/cannondale-six13-spied-tried/

So if you happen to see one on Dartmoor this week say hello as you pass me. If I don't reply it is because I'm close to expiring.

I was there this week too Brutaly Hot and like you good rim brakes and faultless performance.

sniper68

thecycleclinic said:

the op also needs to understand the mechanics of bydraulic brakes.

There is not a hydraulic disc brake on the market than can give that instant lever feel the op wants.

In fact that instant bite is the problem. With rim brakes shimamo, sram and campagnolo recommend the pads are 1.5mm to 2mm from the rim because wait for it, you get peak mechanical leverage when the pad contacts the rim. So by wanting instant bite you decrease the effectiveness of the brake.


The same goes for the disc brakes as instant bite mean rotor rub and less braking force as a small slave cylinder has to be used.

Hard instant brakes on bicycles are a sign of a poor setup or design as its one with lower mechanical advantage.

Admittedly though the shimano r795, rs 685 and r505 brakes are difficult to set up with the bite point half way through the lever travel. The newer brakes are better in this regards.

I beg to differ.
I've had Hydraulic brakes on MTBs for 20+ years and on Moto-X/Motorcyles 40+ years so I fully understand what they do and how to get it.
Bite should start at >5mm and get progressively better >5-15mm.That is my preference.The "bite" on the current set up is >30mm.I have never had any Hydraulic brakes that require that much lever travel before doing their job.
Anyroadup having tried a few more it seems that mine are basically how Shimano want them to be.I've now done 500 miles on these and although I'm getting used to them I'm not happy enough to keep them.I've tried a bike with Shimano/RX4 combo and they're 100% better.That's the way to go.No point building my own bike(s) and then compromising on something as trivial as replacing Calipers.
Thanks for your input everyone!