Improving Shimano brake modulation

[radam]

I have some Shimano SLX M675 brakes with the finned resins pads, 180/160 rotors front/rear. Many seasons on them. I like how easy they are to bleed when the time comes, and like the amount of stopping power. I could do with a bit more modulation. Aside from replacing with different brakes, which of the following would make the most sense?

- Different levers
- Different calipers
- Different pad compounds (or mix compounds)
- Size down on rotors

[Jonny Snow]

I have some Shimano SLX M675 brakes with the finned resins pads, 180/160 rotors front/rear. Many seasons on them. I like how easy they are to bleed when the time comes, and like the amount of stopping power. I could do with a bit more modulation. Aside from replacing with different brakes, which of the following would make the most sense?

- Different levers
- Different calipers
- Different pad compounds (or mix compounds)
- Size down on rotors

Servo Wave is typically what adds power and reduces modulation. If you can lock that out somehow on your lever, that would help.

There are 3 types of higher performance tier Shimano lever that I'm aware of that don't have servo wave - XTR Race, plus the older M756 and M755. I own all 3.

[LeeLau]

Following

[g_man80]

As mentioned, it's somewhat a characteristic of Servo Wave. It's also a characteristic of resin/organic pads. As an easy/cheap starting point, I would suggest to trying sintered (metallic) pads. They have less initial bite than the organic/resin pads; especially when cold. I've found resin pads too grabby to start, but then fade bad on long downhills. The sintered pads manage heat well and the bite increases as they warm up. The trade off is they may be noisy and are a little harder on rotors.

A really cheap/free option would be to remove pad material with an angle grinder. [ | | ] < If that's the pad, take material out between the inside vertical lines (see picture below). You would sacrifice stopping power, but it may not be an issue depending on terrain.

This characteristic is the main reason I switched to SRAM's Guide brakes. The modulation and feel is similar to what I'm used to riding motorcycles. Although, I'm sure I'll miss the bleeding procedure and mineral oil when the time comes.

[ACH]

This characteristic is the main reason I switched to SRAM's Guide brakes. The modulation and feel is similar to what I'm used to riding motorcycles. Although, I'm sure I'll miss the bleeding procedure and mineral oil when the time comes.

Also following...
I have recently been riding Magura Trail Carbons on one of my bikes and have been impressed with the modulation and feel.

[toast2266]

This characteristic is the main reason I switched to SRAM's Guide brakes. The modulation and feel is similar to what I'm used to riding motorcycles. Although, I'm sure I'll miss the bleeding procedure and mineral oil when the time comes.

The bleed system on the newer generations of Guides is one of the best things about them. Aside from being fairly straightforward and non-messy, it's just super easy to get a dialed bleed and get whatever lever feel you want. Like a long throw? no problem. Like a softer / spongier feel? no problem. Like a short throw / firm feel? no problem.

And yeah, DOT fluid is nasty, but the new system makes it pretty easy to not end up with fluid all over the place.

[evdog]

Let's check back in a year and see if you still feel that way about the Guides.

[toast2266]

Let's check back in a year and see if you still feel that way about the Guides.

I've owned probably 15 sets of guides, including every model and model year they've ever made. Every single one of them has been problem free.

On the other hand, I got back on some shimanos for a while this spring. Those things suck. Shitty modulation and they wouldn't hold a good bleed.

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[mtngirl79]

This is why I have hope brakes.

[rideit]

Read this whole thread, I DARE ya!

http://ridemonkey.bikemag.com/thread...9#post-4281729

[bagtagley]

My Guides were made by vampires and like to lock up in the sun.

That thread convinced me that brakes are worth spending some money on, and that frankenbraking makes my head hurt, so I grabbed some Hopes when Jenson had them on sale. It also made me really want a set of Trickstuff brakes. As soon as my YouTube channel blows up, they’re mine!

[Dantheman]

My Guides were made by vampires and like to lock up in the sun.

You can probably warranty those. Sam's did the same thing, new ones are all good. Have your LBS check the serial numbers.

[LeeLau]

Also following...
I have recently been riding Magura Trail Carbons on one of my bikes and have been impressed with the modulation and feel.

I have problem free Magura MT7s and Trails. My wifes Shimanos are terrible in terms of lack of modulation.

Shops in Whistler had massive issues with earlier Guides, none with Codes.

[jono]

Also loving the Maguras. Took a couple rides to get used to that much stopping power. I do miss tool-free adjustment about twice a year.

[LC]

Shimano SLX M675 brakes ... Many seasons on them.

If you've never done it, lubing your pistons is worth a try, and free/cheap. Remove the pads, pump the lever a few times and clean them up nice with isopropyl - a q-tip works fine but Park had a video last year about flossing with isopropyl soaked thread which probably does a better job. Push them back in, pump out again and watch how they move. If they move differently to each other then you're not getting the most from your brakes. Some people use mineral oil to lube but others say that can damage the seals. Castrol red rubber grease is recommended a lot so that's what I use. Paint a thin coat on each piston, pump them in and out a few times and recheck. You can isolate single pistons by jamming a tyre lever against the other one. Just be careful not to pump them out too far especially when isolating single pistons. Push them back in when you're happy and clean up the inside surfaces of the caliper with isopropyl.

I do this every couple of pads changes (Zee brakes) and I can always tell the difference in feel. I'm a big fan of this "mini bleed" or "bubble bleed" procedure too: http://www.epicbleedsolutions.com/bl...no-mini-bleed/ - I do this maybe every 5 rides using half a Reverb syringe as a threaded reservoir at the lever, takes 5 minutes and really improves lever feel on the Zees as the pads wear thinner. The only downside is that you need to remove the lever bleed port screw before resetting pistons and be more careful that the lever isn't squeezed when the bike is in transit with the wheels removed.

Also, buy (or make) a snake eye screwdriver so that you can back out the free stroke screw before bleeding and retighten after bleeding. Even better, swap those screws for hex grub screws (just be careful to stop when you feel slight resistance on tightening or you'll snap the part that the end of the screw rests against). Yes, the Shimano free stroke screw does do something.

[radam]

If you've never done it, lubing your pistons is worth a try, and free/cheap.

Interesting, I will definitely give this a try. Didn't even know this was a thing, but makes sense.

[Jonny Snow]

If you've never done it, lubing your pistons is worth a try, and free/cheap. Remove the pads, pump the lever a few times and clean them up nice with isopropyl - a q-tip works fine but Park had a video last year about flossing with isopropyl soaked thread which probably does a better job. Push them back in, pump out again and watch how they move. If they move differently to each other then you're not getting the most from your brakes. Some people use mineral oil to lube but others say that can damage the seals. Castrol red rubber grease is recommended a lot so that's what I use. Paint a thin coat on each piston, pump them in and out a few times and recheck. You can isolate single pistons by jamming a tyre lever against the other one. Just be careful not to pump them out too far especially when isolating single pistons. Push them back in when you're happy and clean up the inside surfaces of the caliper with isopropyl.

I do this every couple of pads changes (Zee brakes) and I can always tell the difference in feel. I'm a big fan of this "mini bleed" or "bubble bleed" procedure too: http://www.epicbleedsolutions.com/bl...no-mini-bleed/ - I do this maybe every 5 rides using half a Reverb syringe as a threaded reservoir at the lever, takes 5 minutes and really improves lever feel on the Zees as the pads wear thinner. The only downside is that you need to remove the lever bleed port screw before resetting pistons and be more careful that the lever isn't squeezed when the bike is in transit with the wheels removed.

Also, buy (or make) a snake eye screwdriver so that you can back out the free stroke screw before bleeding and retighten after bleeding. Even better, swap those screws for hex grub screws (just be careful to stop when you feel slight resistance on tightening or you'll snap the part that the end of the screw rests against). Yes, the Shimano free stroke screw does do something.

[Jonny Snow]

...........will definitely give this a try. Didn't even know this was a thing........

That's what she said!

[Dee Hubbs]

You can isolate single pistons by jamming a tyre lever against the other one. Just be careful not to pump them out too far especially when isolating single pistons. Push them back in when you're happy and clean up the inside surfaces of the caliper with isopropyl.

The way professionals do this is to make a modified bleed block. Take a yellow Shimano bleed block and cut it in half. (Photos to come)
Place the bleed block in the caliper and pump the one piston out, with out fear of plopping the piston onto the floor.
Clean, lube, push the piston back in, flip the bleed block and work on the other piston.
Repeat, repeat.

[El Chupacabra]

If you lube the piston, does whatever you use to lube it (that Castrol rubber seal compatible grease or whatever) also mix with the brake fluid? IOW, does hydraulic fluid push directly against the back of the piston? Or is it sealed off somehow such that the grease won't mix with fluid?

[jm2e]

As I’ve discovered a couple times recently, popping out a piston really isn’t a big deal. Just line it up and press it back in.
Well lubed, free floating pistons make you weep like a ninja mechanic.
Call me crazy, I love my shimano brakes. Zee, Saint, XT, SLX, they’ve all worked reliably over the years. The only times I think more modulation could help is when I’m trying to figure out how to do a stoppie, or better yet a Switchback Nose Pivot. At this stage, I don’t think it’s the brakes as much as my lack of skillz.


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[LC]

The way professionals do this is to make a modified bleed block. Take a yellow Shimano bleed block and cut it in half. (Photos to come).

I'll raise you. Quarter block cut off for 4-piston brakes:



Not pretty but it works really well. I only did this recently and used it once - so much easier than holding the full block between one pair of pistons plus a tyre lever against one single piston all with one hand while pumping the lever with the other! Should have done this years ago.

If you lube the piston, does whatever you use to lube it (that Castrol rubber seal compatible grease or whatever) also mix with the brake fluid? IOW, does hydraulic fluid push directly against the back of the piston? Or is it sealed off somehow such that the grease won't mix with fluid?

I guess in theory it could mix a little. I coat the perimeter of the exposed piston with grease then push it back in - some grease gets wiped off and a tiny layer remains on the piston. I guess a little grease could transfer to inside the caliper body when the piston is fully pushed back inside the caliper and then mix with oil when the piston pushes back out again but it must be a minuscule amount and I've never had any problems.

Some people do recommend the brake's own oil but some say that can swell or damage seals. I think Hope's videos say copperslip grease or something like that, maybe try to find their video. Castrol Red Rubber grease seemed like the safe option to me and lots of motorbike forums say it's the one to use. Works well for me anyway and a tiny pot of about 10-20ml on eBay UK was very cheap.


Wizard? Nah, I just like keeping my expensive toys running nice. I've always used Shimanos (SLX twice, Zee twice) - I know they have "less modulation" than SRAM but I'm used to the Shimano feel, and SRAMs feel a bit under-powered whenever I switch bikes although I do like the lever build quality on SRAM. I did think about switching my old Zee levers to XTR Race levers to see if the modulation improved, after one lever got a little leaky but I ended up just getting full new Zees cheap and keeping the old ones as OK spares. A racer & guide friend of mine switched last year from a few years of Zees to SRAM's e-bike brakes (Guide lever/Code caliper I think) because I think his hookup was only for SRAM and he now says they're his favourite ever.

[LC]

As I’ve discovered a couple times recently, popping out a piston really isn’t a big deal. Just line it up and press it back in.
Well lubed, free floating pistons make you weep like a ninja mechanic.
Call me crazy, I love my shimano brakes. Zee, Saint, XT, SLX, they’ve all worked reliably over the years.

I popped an SLX piston out once, along with a bit of oil. It went back in fine but needed a full bleed. Popped a Zee piston almost all the way out once, slightly angled, pushed it back in and the bleed still felt fine.

No Shimano problems for me either. You see people whinge about inconsistent bite point a lot online but I've never seen it. Keeping them topped up with the "mini bleed" I linked to above keeps them feeling nice and consistent as the pads wear, maybe that's what I'm doing different. I find that after maybe 5 big rides on a new set of pads I get more lever throw before the pads really bite with a firm lever feel and that's when I do to mini bleed. I only do a full bleed once per year just to flush out old oil.

[ridinshockgun]

Whoah.... I come here and realize I have a problem I haven't noticed in 4 years with XT brakes Guess I need to spend a lot of money and time now to fix this new "problem".

I wrecked about 2 years ago and bent my front XT brake lever down a bit, after rotating the lever up a few degrees to line it back up I think it really helps modulation and ergonomics so you can try that.

[stuckathuntermtn]

Trucker sintered pads off Amazon for $12. No fins. A little heat makes them really start to work and the metal pads don't have that initial bite that can take you by surprise.
I'm also running XT rotors in 8 and 7 inches. Pretty sure my brakes are the same ones.