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Increasing lever throw on SRAM guide RS

Dec. 3, 2018, 8:12 p.m.
Posts: 151
Joined: April 15, 2017

Got my front and back brakes setup, bled and lubed the pistons - they all advance normally now

BUT my rear seems to come on in half of the lever movement compared to my front. Now I could try to train my hand to a more delicate lever movement, but this a machine dammit and they serve us, not the other way around,

So what is the secret sauce for creating more lever travel/throw for the same amount of brake modulation? I tried re-pressurising the system after bleeding. No bubbles etc

any ideas?

Dec. 3, 2018, 8:30 p.m.
Posts: 1904
Joined: May 2, 2004

Rs is the one without the contact point adjustor dial right? That's exactly what that dial does you can use it to keep the 'bite point' in the same place as the pads wear, although IME it only helps on the first chunk of the pads life.

On the RS I have 'adjusted it' by using the bleeding edge port and pushing a little extra fluid in, kind of works sometimes, scared to do too much and mess up the brakes though I think I did that on one bike

Dec. 3, 2018, 9:40 p.m.
Posts: 151
Joined: April 15, 2017

yeah, the additional 'c' option is possibly what I should have ponied up for, but I can't figure why my front has lever throw that isn't matched by the back.

Dec. 3, 2018, 11:15 p.m.
Posts: 787
Joined: June 26, 2012

I had my Guide RS bled by a mechanic and put in brand new pads, and they came back with less lever throw than I’d like. After a couple weeks and 2-3 rides, the lever throw increased and is now how I like it. My guess is that the pads wore a touch and the brake fluid ingested a bit of air.

Dec. 4, 2018, 12:06 a.m.
Posts: 1904
Joined: May 2, 2004

Are the pads both new, one set could be more worn than the other

Dec. 4, 2018, 5:06 a.m.
Posts: 169
Joined: Nov. 6, 2006

one rotor worn more than the other?

Dec. 4, 2018, 8:28 a.m.
Posts: 151
Joined: April 15, 2017

all pads new, all rotors new, new bleed

It all brakes great but the throw for the rear is 1/2 the distance than my front. I think there's some step I didn't do when finishing up meaning I over pressurised? Well, I'll stick the prescribed riding a lot diet.

Dec. 4, 2018, 2:42 p.m.
Posts: 3383
Joined: Dec. 17, 2003

Pop the pads out, pull the lever a few times to push the pistons out (careful now). Lube the pistons with some DOT fluid on a q tip and work them back in. Rebleed the brake and see if that has improved things. It could be that one of the sets of pistons is not retracting properly and that's the brake that has the short throw.

Do the brakes feel the same with the bleed block in - or is it just with the pads and rotor in place?

Dec. 4, 2018, 4:17 p.m.
Posts: 151
Joined: April 15, 2017

The brake lever feels locked up with the block in place. I did lube the pistons and got equal progression, but I've got no problems doing that all again, it was quite relaxing.

I feel like it's time to do something weird like introduce a little bubble into the rear master cylinder. Some kind of mechanic's secret heuristic that you learn by experience. At least bleeding them is easy as pie.

Dec. 4, 2018, 10:32 p.m.
Posts: 17725
Joined: Oct. 28, 2003

Page 7, but do it on the front brake which has too much throw...  almost what nouseforaname said. 

https://www.sram.com/sites/default/files/techdocs/gen.0000000005811_rev_a_2017-2019_guide_rs_r_english.pdf

Dec. 7, 2018, 11:18 a.m.
Posts: 151
Joined: April 15, 2017

Thanks, I think I'll have to tear it all down soon and rebuild. The lever throw on my front is the baseline that I want for my rear. All the information out there appears to only deal with reducing lever throw.

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