Ask the experts

[klauss]

Both Sram G2 RSC 4 pot pistons on my bike have 1/4 pistons that don't retract well. I've manually worked them back in a few times to try to get things moving again but they still don't like retracting.

New brakes?

[climberevan]

Have you meticulously cleaned the pistons' surfaces after pumping them out without the pads in? They eventually get dirty and will drag on the seals unevenly. I bet doing that and then doing a solid bleed will fix your issue.

[klauss]

Thanks climber11. No, I just through some lube down there and worked them in/out (without the pads in) probably fkn it up more

[joetron]

Like “lube” lube or DOT fluid? Actual lube is probably a really bad idea.
Evan’s technique is good, but once clean, I like to dab some DOT fluid on the piston surface with a q-tip to lube the piston/o-ring interface.
Then push them back in and spritz/wipe with isopropyl to clean off any excess


Sent from my iPhone using TGR Forums

[klauss]

Yeah, I sprayed some lube/penetrant on the subject pistons. Seamed to fix one but not the other. I’ll peel everything off and light it on fire

[Beaver]

I just bought an Orbea Rallon with a Fox FLOAT X Performance 2-Position Evol LV shock 230x60mm. There is a guy locally with a Ohlins ttx coilover 230x65mm with a spacer to reduce stroke to 62.5mm. 62.5 bumps me up to just over 168mm travel. Its been a long time since I've run a coil. How much better will my ride be?

[toast2266]

Yeah, I sprayed some lube/penetrant on the subject pistons. Seamed to fix one but not the other. I’ll peel everything off and light it on fire

That might be your issue. Dot fluid is silicone based. A lot of lubes are petroleum based. Putting a petroleum based lube on the brakes might have contaminated the seals - the seals will swell up, which would explain the sticky piston.

Those calipers are rebuildable. You can get new pistons and seals for pretty cheap, and the rebuild kit comes with dot grease to lube everything up.

[toast2266]

I just bought an Orbea Rallon with a Fox FLOAT X Performance 2-Position Evol LV shock 230x60mm. There is a guy locally with a Ohlins ttx coilover 230x65mm with a spacer to reduce stroke to 62.5mm. 62.5 bumps me up to just over 168mm travel. Its been a long time since I've run a coil. How much better will my ride be?

1) make sure you'll still have enough clearance at bottom out.

2) tough to say how much better it'll be since it depends on the tune, etc., but odds are that small bump sensitivity will be a bunch better, big hit performance will be a little worse, and the bike will bob more while pedaling.

[Beaver]

1) make sure you'll still have enough clearance at bottom out.

2) tough to say how much better it'll be since it depends on the tune, etc., but odds are that small bump sensitivity will be a bunch better, big hit performance will be a little worse, and the bike will bob more while pedaling.

At 62.5 I will have bottom out clearance on a large frame, 65 gives tire buzz on bottom out.

I hadn't thought about the additional pedal bob. As for big hits, I won't say never but I'm old & that shit is supposed to be behind me by now.

I think I'll ride as is for a while.

Thanks

[meepmoop24]

Yeah, I sprayed some lube/penetrant on the subject pistons. Seamed to fix one but not the other. I’ll peel everything off and light it on fire

This works well for cleaning pistons that are stuck: https://www.pinkbike.com/news/tech-t...ol--video.html

[klauss]

This works well for cleaning pistons that are stuck: https://www.pinkbike.com/news/tech-t...ol--video.html

I gave this floss with alcohol another go and the one problem piston appears clean, but is stubbornly not retracting. Have to manually push it back in. Applied some DOT fluid as a last step and it's still being a bitch

That might be your issue. Dot fluid is silicone based. A lot of lubes are petroleum based. Putting a petroleum based lube on the brakes might have contaminated the seals - the seals will swell up, which would explain the sticky piston.

Those calipers are rebuildable. You can get new pistons and seals for pretty cheap, and the rebuild kit comes with dot grease to lube everything up.

This is the next step. Probably messed up the seals like you reckon

danke schoen

[schuss]

Any 27.5 bikes that people like? My wife tried out a Stumpy with 29ers and didn't like it (she's very much a beginner), but we're rapidly becoming a biking family with the kids. Looks like Santa Cruz has some (5010 and Juliana Furtado), but curious if we should look at other options.

[rideit]

I got my wife a '20 Rocky thunderbolt, she loves it if you could find a lightly used or NOS one. 140 front and rear, does everything well...

[schuss]

I got my wife a '20 Rocky thunderbolt, she loves it if you could find a lightly used or NOS one. 140 front and rear, does everything well...

Closest rocky dealer is an hour+, unfortunately.

[jono]

Which brands are close?

[Falcon3]

Giant Liv Intrigue. Basically a women-specific Trance. 27.5, 150/140.
74.5 seat tube, 66.5 heat tube.
Clearance for 2.6” tires
Not super progressive but decent all-around numbers. Very easy to throw an Angleset in to bring it a bit more progressive.
Very attractive entry price and Giant frames are well-made aluminum, super tough, and worth upgrading as they wear out/she progresses in skill.

$2700 and the best part is they’re actually available.

[jackstraw]

Shimano rotors. What is the deal with those little washers that cover two of the holes? Are they necessary? I don't know what happened to them, but I cannot imagine they do much of anything. Locktite, torque, and good to go is my thought.

[rideit]

I have thrown them away for 20 years...

[jackstraw]

I have thrown them away for 20 years...

And you're not dead yet, so I guess I'm good!

[toast2266]

Shimano rotors. What is the deal with those little washers that cover two of the holes? Are they necessary? I don't know what happened to them, but I cannot imagine they do much of anything. Locktite, torque, and good to go is my thought.

They're supposed to keep your bolts from loosening. Rotor bolts coming loose seems like it was more common ~20 years ago, and a few brands took some steps to prevent it (presumably on the advice of their legal staff). Maybe older parts had some weird vibration issues that were rattling bolts loose? I dunno. But I do recall having some extremely frustrated customers whose rotor bolts were backing out every ride despite trying all of the obvious remedies.

Anyways, no, they're not necessary. Throw them away.

[XXX-er]

yeah I remember loose bolts on the hayes discs, you could move some around when enough of them fell out to be a problem, the screws were Torx instead of the Allen key that every one carried so they would get stripped cuz people thot they were allen

careful not to get loctite on yer brake padz

[mmmm...pow!]

Rear hub maintenance time. What should I use to lube the pawls? Yeah, I know there are specific oils and greases for this, but I try to avoid buying stuff that will sit around the shed for years unless I have to, so I'm thinking about using something already sitting around the shed. On hand I've got various chain lubes, synthetic grease, Fox Gold 20 weight and 10 weight fork oil, 5w30 synthetic motor oil, tranny fluid, and power steering fluid. I'm thinking grease might be a bit thick? Also, a little searching shows people using oils from 2.5 weight up to 90 weight. A bike shop previously used Dumonde Tech freehub oil in one of my other hubs and it made it super quiet, so if I have to buy something that's probably it.

[forty]

Rear hub maintenance time. What should I use to lube the pawls? Yeah, I know there are specific oils and greases for this, but I try to avoid buying stuff that will sit around the shed for years unless I have to, so I'm thinking about using something already sitting around the shed. On hand I've got various chain lubes, synthetic grease, Fox Gold 20 weight and 10 weight fork oil, 5w30 synthetic motor oil, tranny fluid, and power steering fluid. I'm thinking grease might be a bit thick? Also, a little searching shows people using oils from 2.5 weight up to 90 weight. A bike shop previously used Dumonde Tech freehub oil in one of my other hubs and it made it super quiet, so if I have to buy something that's probably it.

the dumonde tech freehub oil is worth having on hand if you do your own maintenance, its good shit

however for the dirtbag mechanic ive used a little slick honey mixed with triflow to a nice runny consistency and had good luck

i also have some ptfe lube from hadley thats super thin and awesome, but being so thin needs more frequent application if not in well sealed environment

[jackstraw]

Anyways, no, they're not necessary. Throw them away.

Apparently I already did...or I lost them. Idk.

I finally said f-it and am getting multiple wheels set up for my Hightower. I got a free SC rear wheel, had an older wheelset from my kids Enduro, and just bought a new front wheel. All 650B. I have a 29er for dirt, 650b 2.8 for mud season, and 650b 2.8 studded set up for ice season. Finally bought cassettes, rotors, and had these old rotors, less the washers, sitting around to put this whole thing together. I hate not having a bike for our various conditions.

[Jtlange]

the dumonde tech freehub oil is worth having on hand if you do your own maintenance, its good shit

It even works on Shimano derailleur clutches better than shimanos own internal hub grease.