Mechanics Quick Question Thread [Ask Questions Here]

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Mechanics Quick Question Thread [Ask Questions Here]
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Posted: May 15, 2022 at 20:36 Quote
BryanBobo wrote:
The other day I noticed my disc brakes were rubbing. After quick inspection I realized it wasn’t alignment it was just that the caliper pistons were too far out and squeezing the caliper lightly. I removed the lever bleed port screw, used a pad spacer to push the pistons in the rotor back a bit, good as new everything worked fine. After a few more rides I’m in the same issue again where the pads have progressed to the point of squeezing the caliper even when not engaged. Any idea what could be happening here/causing this?

when was the last time you cleaned your caliper? it could be that the pistons are sticky and cant retract on their own.

Posted: May 15, 2022 at 22:42 Quote
Sticky pistons. Lube them with DOT fluid and rebleed. If they're Shimano brakes lube them with mineral oil.

Posted: May 16, 2022 at 1:10 Quote
I have a bleed block with one corner cut out so I can extend each piston separately, lube it, and move onto the next.
Someone on Thingiverse has a file for the same thing, if you have access to a 3D printer.

Solved a similar problem for me where the pistons would retract slowly, causing the brake to rub for a while after each pull.

Posted: May 16, 2022 at 6:09 Quote
Thank you all! Very helpful. Will give these suggestions a try

Posted: May 16, 2022 at 18:42 Quote
Have a carbon wheel that had a slight wobble so i decided it was a good idea to get a tension gauge and go over it. Made tension all even and as recommended
Made the wheel much worse, whats the best thing to do moving forward? Back them all off and bring up to tension again?

Posted: May 16, 2022 at 19:00 Quote
Yep, bring it all the way down then true/dish it and come back up to tension.

Posted: May 16, 2022 at 22:19 Quote
has anyone had bushing play in a fox 38? im having issues with a sensation that feels like a loose headset but shop mechanic says its not that, feels like a fork issue.

Posted: May 17, 2022 at 2:00 Quote
Garradmiller wrote:
Have a carbon wheel that had a slight wobble so i decided it was a good idea to get a tension gauge and go over it. Made tension all even and as recommended
Made the wheel much worse, whats the best thing to do moving forward? Back them all off and bring up to tension again?

If you set all the tensions perfectly equal, the wheel wont be straight at all. The trick to wheelbuilding is to adjust the tensions so thatthe rim runs straight, while keeping the tensions as even as possible (not the "as possible" part). The better you are at wheelbuilding, the more even the tensions in the finished wheel will be. However, they will never be perfectly equal.

Posted: May 17, 2022 at 2:01 Quote
newbermuda wrote:
has anyone had bushing play in a fox 38? im having issues with a sensation that feels like a loose headset but shop mechanic says its not that, feels like a fork issue.

Any fork can develop loose bushings. It's quite possible that your mechanic is correct

Posted: May 17, 2022 at 6:32 Quote
Looking at a DH wheelset: is a Mavic Deemax with a 7sp DH shimano freehub compattible with a GX DH 7 speed cassette?

Or is the GX DH for a normal shimano freehub because of the big back spacer/spoke protector?

And if it doesn't fit what cassette should I use with the deemax to get the 7speed set up working?

Posted: May 17, 2022 at 8:03 Quote
Grumposaur wrote:
Looking at a DH wheelset: is a Mavic Deemax with a 7sp DH shimano freehub compattible with a GX DH 7 speed cassette?

Or is the GX DH for a normal shimano freehub because of the big back spacer/spoke protector?

And if it doesn't fit what cassette should I use with the deemax to get the 7speed set up working?

I had a $30 11-42 cassette in decent shape, that I stripped a few cogs out of to get down to 11-36 7s for my dh bike. The 11-25 10s was way too many steps. I used some spacers to make up for the missing 3 cogs. Definitely the 'hack' way to do it and I haven't ridden it yet with the bike parks not open yet. Would be curious about what else is out there!

Posted: May 17, 2022 at 8:31 Quote
Grumposaur wrote:
Looking at a DH wheelset: is a Mavic Deemax with a 7sp DH shimano freehub compattible with a GX DH 7 speed cassette?

Or is the GX DH for a normal shimano freehub because of the big back spacer/spoke protector?

And if it doesn't fit what cassette should I use with the deemax to get the 7speed set up working?

The GX DH cassette is listed as compatible with a 8/9/10/11-speed HG freehub body so it's only 7-speed because of the spacer. Are you sure the wheelset has specifically a 7-speed freehub body? The original HG freehub was narrower and only takes old-school 7-speed cassettes, but I doubt that's the freehub you're talking about if it's on a Deemax set that you're looking to use now.

Posted: May 17, 2022 at 9:29 Quote
melanthius wrote:
Grumposaur wrote:
Looking at a DH wheelset: is a Mavic Deemax with a 7sp DH shimano freehub compattible with a GX DH 7 speed cassette?

Or is the GX DH for a normal shimano freehub because of the big back spacer/spoke protector?

And if it doesn't fit what cassette should I use with the deemax to get the 7speed set up working?

The GX DH cassette is listed as compatible with a 8/9/10/11-speed HG freehub body so it's only 7-speed because of the spacer. Are you sure the wheelset has specifically a 7-speed freehub body? The original HG freehub was narrower and only takes old-school 7-speed cassettes, but I doubt that's the freehub you're talking about if it's on a Deemax set that you're looking to use now.
Taking of the spacer could maybe work, but I like a limit ring/spoke protector on my cog.

The reason I'm doubting that it is actually sounds like old school 7speed. These are the options I got here: https://www.bike-components.de/en/Mavic/Deemax-21-Disc-6-bolt-29-Wheelset-p81956/

black/29" Set (front 20x110 + rear 12x157) Shimano
vs
black/29" Set (front 20x110 + rear 12x157) Shimano 7-speed

Thing is: I'm not looking to buy it there, else I would get the std Shimano one. But I found something on a local board listing it specifically as 7speed only. And could find clear info on mavic site. By know I read a product article saying that the 7 speed has wider flanges for stiffer rear wheel. Anyway not to convinced I should get that.

Btw any advice for a 157x12 DH wheelset that is not to expensive but will last a while. Alternatively I was thinking of a custom set, with FR560 on 350's or the stock hubs of the bike.

Posted: May 18, 2022 at 9:44 Quote
I have an Orbea/OC dropper that needs bushing service, but Orbea’s kit is back ordered. Pictures from the internet suggest that the plastic keys and bushings for sdg and other wintek based posts (giant, bontrager) might be the same thing. Does anyone have any experience with these? Thanks!

Posted: May 19, 2022 at 12:20 Quote
Quick question:
What would be the expected torque value when reinstalling thru axle in carbon rear triangle?
Thanks in advance.


 
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