Ask the experts

[troth]

I need some brake help. I was trying to fix a sticky piston and ended up popping one of the piston completely out of the caliper. Lost a lot of brake fluid and I put the piston back in as quick as I could. Obviously with the lost fluid the pistons wont move anymore. Is the fix just a brake bleed? Or is this something more complicated?


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[pureantigravity]

I need some brake help. I was trying to fix a sticky piston and ended up popping one of the piston completely out of the caliper. Lost a lot of brake fluid and I put the piston back in as quick as I could. Obviously with the lost fluid the pistons wont move anymore. Is the fix just a brake bleed? Or is this something more complicated?


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I think a bleed is all you need. Just check that the seal is not kinked or something and I'd suggest pushing the piston all the way in while you do the bleed. Put a popsicle stick in between the pads and get as much air out of the piston chamber to make the bleed go faster. And then bleed as usual. Pretty sure I popped a piston one time and its no biggie. Sometimes people pop them when the wheel is out and they pull the brake levers unwares.

[sf]

Brake adapteres somehow confuse me. Considering a frame with a IS brake mount, and they reccomend a IS/PM adapter --> PM185, or a IS/PM203 adapter.

I'll probably run Codes with 200mm rotors, and haven't found a IS/PM200 adapter yet. What's the best way to solve this?
- IS/PM, then PM185 to PM200 somehow?
- IS/PM203, and run the Codes with 203 rotors?
- IS/PM, then 15mm of spacers and whatnot

Or am I just overthinking it?

[HAB]

Brake adapteres somehow confuse me. Considering a frame with a IS brake mount, and they reccomend a IS/PM adapter --> PM185, or a IS/PM203 adapter.

I'll probably run Codes with 200mm rotors, and haven't found a IS/PM200 adapter yet. What's the best way to solve this?
- IS/PM, then PM185 to PM200 somehow?
- IS/PM203, and run the Codes with 203 rotors?
- IS/PM, then 15mm of spacers and whatnot

Or am I just overthinking it?

https://www.worldwidecyclery.com/col...mm-rear-rotors

[sf]

https://www.worldwidecyclery.com/col...mm-rear-rotors

Thanks.

But that's just a great example of what makes my brain hurt. It's a 60mm adapter, won't it's compability with 200mm rotors depend on the frame and what size rotor the frame is "made" for?

[Dee Hubbs]

Thanks.
But that's just a great example of what makes my brain hurt. It's a 60mm adapter, won't it's compability with 200mm rotors depend on the frame and what size rotor the frame is "made" for?

The frame will always be "made" for a 140mm or 160mm IS standard. It will not be made for a 143mm? or something different.
If you want to run SRAM 200's you buy a SRAM specific adapter mount for +60mm.
If you want to run Shimano 203's you buy a Shimano specific mount adapter for +63mm.

And for the people who say, just run your 200mm rotors with Shimano 203 set up, "it will be fine" dont know what they are talking about. It will cause brake pad overhang the rotor, and a lip will wear into the brake pad, and once the pads wear to a certain point, the 2 lips will touch and eventually the only thing that touches when you squeeze the brakes are the two pads allowing the rotors to freely spin with zero breaking.
Propper adapters are less than $20, don't fuck around with washers or home made spacers.

[sf]

There it is. Thanks to both of you.

[GeorgiaSnow]

Lots of insert hate. Only thing I’ll say it’s a little reductionistic to say they are only for lower pressures/flat protection. Most are a pretty significant change in volume, so they change the riding characteristics of your tire pretty drastically. People spend a lot of time playing with spacers, air pressure, rebound, etc. on a fork/shock to find the ride that suits them, why not mess around with something that could drastically change the way your tire behaves? What sold me wasn’t what someone said on a forum but just running with and without and liking the “with” in the rear better for my weight/riding/location and not caring about the weight ( I prefer a higher pressure in the front and didn’t feel like it rode better at that pressure with insert). Obviously w/ supply and cost stuff right now it’s harder to experiment but ride what you like. Still a cheaper thing to mess around with than a lot of other stuff in the bike world.

Also, going to mess around with queso chains for road bike and stumbled upon the horse carcass of wax in this thread (at this point only a few hairs remain?). Amazing picking clean of that poor animal. Lol


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[J. Barron DeJong]

DT Swiss Hub Bearing Specs.

Anyone with wisdom and experience want to tackle this for me? Two local shops have failed and I don't want them identifying by dismantling if I can't find the parts to put them back together.

240s J-Bend 6-bolt hubs. Bought used in 2017. Blue Giant/DT Swiss Labels (Glory Take-Offs)
12 x 150 Rear with xD Freehub (no idea if it's 3 of the same size, or 3 totally different sizes)
20 x 110 pre-boost Front (I'm 80% sure they're 6805)

Does your hub have an ID number on it? Have you tried entering that number on the DT Swiss product support page?

https://www.dtswiss.com/en/support/product-support

[Whiteroom_Guardian]

I'm kinda on the fence about inserts again. Been running rear Cush Pro and nothing in the front since last October. 29". Insanely nice wheels that I got on a bro-deal (Enve M6). DD casing tires. Just rode two hard days at Silver practicing for the race next weekend. Pinged the front 2 or 3 times all weekend. Running only 21psi in the front and I weigh about 160lbs fully kitted up.

Adding the weight of CC for long pedally sections seems crazy now. I have run CC Pro in the front before and you can really feel that extra weight.

Only a few times did I feel like the tire didn't have enough support railing hard in a berm.

Probably would have been a good idea to do back to back laps with and without front CC. The dampening in the front does help it feel glued, but I am also running a push coil conversion in a 36 and that already really helps the front end.

I love tinkering and have a CC XC weight insert I could try in the front......but probably shouldn't fuck with it less than a week from the race.

[toast2266]

I'm kinda on the fence about inserts again. Been running rear Cush Pro and nothing in the front since last October. 29". Insanely nice wheels that I got on a bro-deal (Enve M6). DD casing tires. Just rode two hard days at Silver practicing for the race next weekend. Pinged the front 2 or 3 times all weekend. Running only 21psi in the front and I weigh about 160lbs fully kitted up.

Adding the weight of CC for long pedally sections seems crazy now. I have run CC Pro in the front before and you can really feel that extra weight.

Only a few times did I feel like the tire didn't have enough support railing hard in a berm.

Probably would have been a good idea to do back to back laps with and without front CC. The dampening in the front does help it feel glued, but I am also running a push coil conversion in a 36 and that already really helps the front end.

I love tinkering and have a CC XC weight insert I could try in the front......but probably shouldn't fuck with it less than a week from the race.

Just swap to a DH casing. More sidewall support, and more flat protection. And less weight gain than CC.

[Whiteroom_Guardian]

Just swap to a DH casing. More sidewall support, and more flat protection. And less weight gain than CC.

Pretty nuts that the Assegai 29" MaxxGrip only has 29g difference between DD and DH.

[toast2266]

Pretty nuts that the Assegai 29" MaxxGrip only has 29g difference between DD and DH.

Huh. Yeah, I'm surprised it's that close too.

That would seem to indicate that there's about the same amount of rubber in both the dd and dh. The dh would just have 2x 60 tpi casing, whereas the dd has 2x 120 tpi. I believe the dh would have a bigger butyl insert in the sidewall as well.

[Whiteroom_Guardian]

Huh. Yeah, I'm surprised it's that close too.

That would seem to indicate that there's about the same amount of rubber in both the dd and dh. The dh would just have 2x 60 tpi casing, whereas the dd has 2x 120 tpi. I believe the dh would have a bigger butyl insert in the sidewall as well.

Bought one and will probably try it on Friday's practice.

[toast2266]

Bought one and will probably try it on Friday's practice.

Nice. And good luck in the race! I've got a friend or two that're heading over for it. Should be a good time.

[cydwhit]

Bear with me, this may be a stupid question...

I'm trying to figure out a (very) budget race timing system that's a step up from two stop watches and a clipboard. I feel like there should be some way to use the NFC reader on my phone, and cheap generic NFC chips ($10 for 30 on amazon type deal) to set up a race timing system. I am no programmer or app developer, but it seems like it should be really easy to have some kind of cloud based app that records each scan and then allows you to find the difference in time between the two scans, thus giving you race results. Have a person with an iPhone scan at the top, another at the bottom, synch their data, and boom, you're racing.

I've done a fair amount of googling and all I can find are the professional level systems that cost as much to rent for a weekend as I'd want to spend total. Am I missing something obvious? Is this a pipe dream? It's freaking 2021, I feel like I should be able to jimmy rig a system that's more streamlined than the stopwatches we've been using since the 90's?

[toast2266]

Bear with me, this may be a stupid question...

I'm trying to figure out a (very) budget race timing system that's a step up from two stop watches and a clipboard. I feel like there should be some way to use the NFC reader on my phone, and cheap generic NFC chips ($10 for 30 on amazon type deal) to set up a race timing system. I am no programmer or app developer, but it seems like it should be really easy to have some kind of cloud based app that records each scan and then allows you to find the difference in time between the two scans, thus giving you race results. Have a person with an iPhone scan at the top, another at the bottom, synch their data, and boom, you're racing.

I've done a fair amount of googling and all I can find are the professional level systems that cost as much to rent for a weekend as I'd want to spend total. Am I missing something obvious? Is this a pipe dream? It's freaking 2021, I feel like I should be able to jimmy rig a system that's more streamlined than the stopwatches we've been using since the 90's?

What kind of race are you looking to time? DH races are easier to do cheap than enduro races (1 finish line with set start times vs. a bunch of finish lines with varying start lines).

But regardless, pretty much every small / beer league race I've seen is still using stopwatches + clipboard. I think it's tough to improve on that for less than ~$500.

[eldereldo]

Are you thinking of something sewn to a race in, or stuck onto the bike? You need to watch with nfc devices, a lot of them won’t work stuck on metal, some have very limited range and others that don’t have these issues won’t work with the NFC readers in phones.

[cydwhit]

What kind of race are you looking to time? DH races are easier to do cheap than enduro races (1 finish line with set start times vs. a bunch of finish lines with varying start lines).

But regardless, pretty much every small / beer league race I've seen is still using stopwatches + clipboard. I think it's tough to improve on that for less than ~$500.

Would probably be just for a DH (we have no DH racing here, I want beer league DH culture, and I'm better at organizing things than I am at racing so I'm trying to figure out how to put it on.)

I'm happy to just do it the watches/clipboard way, but like, we have so much great technology available. NFC chips are so cheap and simple. I'm no programmer, but I feel like it shouldn't be that hard to make it happen?

For Eldelredo: I'd probably sew up velcro bracelets with the chip in them. There are options like this that are already in a button form factor. From there, I'd just need an app that logs the time of each scan, along with the chip's "name" to a spreadsheet. Easy enough from there to use Excel functions to spit out the delta in time between scans. Right? Or am I an idiot?

Having someone scanning at the top, and another at the bottom with an iPhone, seems a lot simpler and more streamlined than stopwatches to me, but maybe it's not. IDK, I may fuck around and buy some chips and experiment. I'd really like to have a timing system for both bike racing, and the occasional DIY skimo race in the winter. For some reason we do not compete enough doing fun things in the mountains here in the Tetons IMO.

EDIT: I think I figured it out. This app if anyone is wondering. I'll give it a test in a week or so.

[teledad]

Not sure if it fits your budget, but this seems pretty close to what you're asking for: https://www.webscorer.com/race-timing-auto

[toast2266]

Would probably be just for a DH (we have no DH racing here, I want beer league DH culture, and I'm better at organizing things than I am at racing so I'm trying to figure out how to put it on.)

I'm happy to just do it the watches/clipboard way, but like, we have so much great technology available. NFC chips are so cheap and simple. I'm no programmer, but I feel like it shouldn't be that hard to make it happen?

For Eldelredo: I'd probably sew up velcro bracelets with the chip in them. There are options like this that are already in a button form factor. From there, I'd just need an app that logs the time of each scan, along with the chip's "name" to a spreadsheet. Easy enough from there to use Excel functions to spit out the delta in time between scans. Right? Or am I an idiot?

Having someone scanning at the top, and another at the bottom with an iPhone, seems a lot simpler and more streamlined than stopwatches to me, but maybe it's not. IDK, I may fuck around and buy some chips and experiment. I'd really like to have a timing system for both bike racing, and the occasional DIY skimo race in the winter. For some reason we do not compete enough doing fun things in the mountains here in the Tetons IMO.

If you're just doing DH, see if you can pick up a used photocell / photogate finish line on ebay. Those things are, at their core, fairly simple. It's basically the same sensor that a garage door uses, hooked up to a clock. A lot of the ones that are designed around racing are a bit more complicated and therefore expensive, but you might be able to find a cheap one.

At least to start with, you'd have a set start order, and you'd send racers at a set time. So the racer at the top would have to start at their designated time. But then the photogate at the bottom would record the exact time they crossed the line.

Eventually, you could make it more accurate by having a second photgate at the top. But then you'd have to input all the data to calculate the exact time.

[jm2e]

Sram GX 10 Speed Short Cage on my DH bike to replace a GX DH derailleur.
Any reason I shouldn't do this? $60 for one vs $120 plus very hard to source for the other. Current derailleur is bent like a motherfucker, but still hanging in there. Just thinking forward during these sparse times.

[toast2266]

Sram GX 10 Speed Short Cage on my DH bike to replace a GX DH derailleur.
Any reason I shouldn't do this? $60 for one vs $120 plus very hard to source for the other. Current derailleur is bend like a motherfucker, but still hanging in there. Just thinking forward during these sparse times.

I believe the 10 speed stuff is "exact actuation" and the newer stuff (including gx dh) is "x-actuation." Which is sram's way of saying they have different cable pull ratios.

[Whiteroom_Guardian]

Nice. And good luck in the race! I've got a friend or two that're heading over for it. Should be a good time.

Thanks. Probably the heaviest competition of the year outside an EWS. Super stacked field. I was putting down some fast times this past weekend. Just need to maintain that pace, keep the rubber down, and pray it doesn't rain too much. Those off cambers roots on the stuff mid mountain is nightmare fuel if it's raining.

[anotherVTskibum]

Would probably be just for a DH (we have no DH racing here, I want beer league DH culture, and I'm better at organizing things than I am at racing so I'm trying to figure out how to put it on.)

I'm happy to just do it the watches/clipboard way, but like, we have so much great technology available. NFC chips are so cheap and simple. I'm no programmer, but I feel like it shouldn't be that hard to make it happen?

For Eldelredo: I'd probably sew up velcro bracelets with the chip in them. There are options like this that are already in a button form factor. From there, I'd just need an app that logs the time of each scan, along with the chip's "name" to a spreadsheet. Easy enough from there to use Excel functions to spit out the delta in time between scans. Right? Or am I an idiot?

Having someone scanning at the top, and another at the bottom with an iPhone, seems a lot simpler and more streamlined than stopwatches to me, but maybe it's not. IDK, I may fuck around and buy some chips and experiment. I'd really like to have a timing system for both bike racing, and the occasional DIY skimo race in the winter. For some reason we do not compete enough doing fun things in the mountains here in the Tetons IMO.

EDIT: I think I figured it out. This app if anyone is wondering. I'll give it a test in a week or so.

Note that the app blog post (admittedly from 2015) indicates that the racer needs to pretty much touch the NFC token to the phone reading it and get an audible beep. That's either a significant additional challenge for your racers or a show-stopper, IMO.

Speaking as a computer geek who was a USAC official for a while and has worked road races with everything from clipboards and stopwatches to pro timing companies running video and picking up racer numbers from it, I'd want to have stopwatches and clipboards as a backup if I was using a chip-based solution.

I'm also a ski-race official (and coach), and I've seen our automated systems—which are a start wand and photocell hooked up to electronic TOD-recording devices and then to a computer—fail for a variety of reasons, at which point we go back to...wait for it...clipboards and stopwatches (and then calculate an offset from the stopwatch TOD to the electronic TOD to hopefully wash out the human reaction time as well as any offset between the TOD set on the devices). Even with a higher-end chip-based system, as an official, I'd really want a human with a clipboard recording bib numbers as they come across the line, and having a stopwatch as well would seem to be a good idea.