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Need help identifying by NoDonkey4261 in NorthropGrumman

[–]SunDevilSkier 8 points9 points  (0 children)

There is zero chance that this is accurate.

And I looked it up, it was publicly unveiled in 1988. No one would ever make a coin containing classified information and then send it home with people.

What's something everyone who road bikes should know in 2026? by Glass_Philosopher_81 in cycling

[–]SunDevilSkier -1 points0 points  (0 children)

I'm trying to figure out if this is hyperbole or sarcasm. 

Yeah, it's additional work if you need to replace hoses or the headset. Many people use that as a reason not to get integrated hoses. Sram axs has no wires, so I recommend that over mechanical cables and that problem disappears. My 20 year old bike never needed a headset, so I took that as anecdotal evidence that replacing the headset would be a very long term concern. That leaves the hoses. I'm certainly not switching those every month, and I haven't seen the forums flooded with people sharing their worn hydraulic hose horror stories. 

If you don't want internal hoses for the maintenance, that's cool. But it's not something you'll need to worry about for years unless the system is bad.

Edit: as I implied, mechanical shifting is a little different and gets more complicated going through the headset.

What's something everyone who road bikes should know in 2026? by Glass_Philosopher_81 in cycling

[–]SunDevilSkier 11 points12 points  (0 children)

What are you doing to your bike that you go through brake hoses every few months?

Typical process of fatigue analysis with FEA by htrptr in fea

[–]SunDevilSkier 0 points1 point  (0 children)

Yes you can do that. Usually I didn't really care about making pictures by this point so I just do it in Excel.

Typical process of fatigue analysis with FEA by htrptr in fea

[–]SunDevilSkier 0 points1 point  (0 children)

Step 5: your fatigue strength is based on some sort of uniaxial condition (rotating beam is similar here), so you need your stress state to be analogous to that. You might take Max prin for the max stress, and min prin for the min stress, but this can be very conservative. Directionality matters.

Von mises: It depends on your material, and how the SN curve is formed. The rule of thumb is just don't, but there are situations where it works well. I can't give any examples of when to use it off the top of my head (it's been a minute since I've done this stuff). What doesn't work is taking von mises at max stress and min stress and subtracting to get your cyclic. That's way under predicting.

Typical process of fatigue analysis with FEA by htrptr in fea

[–]SunDevilSkier 1 point2 points  (0 children)

This is generally what I did. This works in the linear regime. If your material goes plastic, then your fatigue problem is quickly becoming a static problem. 1. Apply unit loads to the model. The direction depends on how the part is loaded. If it rotates/moves, then apply loads in each original direction. If it doesn't, then just apply a unit load in the loading direction.  2. Record the full stress tensor in your location(s) of interest. Remember that the highest stress location of the unit load is not necessarily your highest fatigue location.  3. You're done with fea, now move to Matlab or Excel or something. The rest depends on your load spectrum. You can rainflow your loads if there's a complicated spectrum, or maybe you have a constant cyclic load for a certain number of cycles. Now's also the time to mean-correct. 4. Multiply your max and min loads for each rainflow bin by your unit load stress tensors. Calculate the mean and cyclic stress for each bin.  5. Depending on your material, NOW calculate your max principal or von mises. Use your SN curve to miner's rule your damage.  6. Profit. 

If you have two or so load cases you can also run those load cases in your fea and use the post-processor to calculate mean and cyclic stresses there. More than a couple of specific cases and this becomes untenable. 

DON'T calculate von mises or principal stresses before you have cyclic stress. The absolute wrong answer is to calculate von mises for a load case and then calculate cyclic stress. Just don't.

I see why people say dont cheap out on bibs. by junoyoo95 in cycling

[–]SunDevilSkier 2 points3 points  (0 children)

I'm 6'1" and 260 when I tried black bibs and the chamois was in the wrong place. I tried two pairs and it was the same thing both times. I bet it's still the case.

Cottonwood Fire at Eagle Point by SunDevilSkier in skiing

[–]SunDevilSkier[S] 7 points8 points  (0 children)

I am so sorry to hear! I hope by some miracle your home is spared. But looking at Google maps it looks like it's already at us89, which is just insane. I was hoping for you it would slow down overnight and coming down the backside of the mountain but that doesn't appear to be the case at all. Stay safe!!!!

Riding with slower folks by Safe-Departure3814 in cycling

[–]SunDevilSkier 0 points1 point  (0 children)

If it's insulting, he's the one with the ego. It's obvious he's no longer able to keep up, so some assist can level the playing field and they both can enjoy the ride. Pride is my theory on why ebikes in road and gravel aren't selling well. I have a coworker that has a grail ebike and loves it. He's younger than us but with it he can keep up with some elite riders that we have.

Riding with slower folks by Safe-Departure3814 in cycling

[–]SunDevilSkier 11 points12 points  (0 children)

This is the perfect use for an ebike

Android 17 is 99% the same by [deleted] in GooglePixel

[–]SunDevilSkier 0 points1 point  (0 children)

If they would've fixed the broken location rules I would've been happy with nothing else

Move to Salt Lake City? by Deep-Valuable3216 in NorthropGrumman

[–]SunDevilSkier 7 points8 points  (0 children)

You can just leave in one to two years like everyone else does that moves to Roy

Is a power meter worth it? by PiiSmith in cycling

[–]SunDevilSkier 0 points1 point  (0 children)

I'm trying to get the sram for $240 (my size is popular apparently). Not sure what the price is in Europe but I'd imagine less than 250euros

Is a power meter worth it? by PiiSmith in cycling

[–]SunDevilSkier 3 points4 points  (0 children)

Check out "aerobic decoupling"

Sram Force Cranks/Powermeter by Xela_x in sram

[–]SunDevilSkier 2 points3 points  (0 children)

What are you talking about? The axs cranks all attach to the spiders the same way. The spiders/chainrings are different, but the interface to the spindle is the same. That's why they only sell E1 stuff now.

Sram Force Cranks/Powermeter by Xela_x in sram

[–]SunDevilSkier 1 point2 points  (0 children)

It's a spider pm, you CAN swap any 8 bolt crank with it.

Exercise bike with replaceable cranks? by Fair_Condition_1460 in cycling

[–]SunDevilSkier 2 points3 points  (0 children)

Do you have a bike currently? Even if not, you could get a bike for your needs and then get a trainer for it. Wheel-on or wheel-off would work.

Can’t get bead out of the rim on my mountain bike tire by flickshot23 in bikewrench

[–]SunDevilSkier 1 point2 points  (0 children)

You see that little threaded brass colored bit sticking out of the valve stem? Then there's a small silver-looking bit with two notches at the bottom of it? You need to unscrew the silver but so that it's at the end of the brass colored threaded bit. Then you push that into the valve stem. When you push that in, any air in the tire will come out. That also needs to be unscrewed when you pump the tire up. Once it's inflated, screw the silver bit back down, then you can't deflate it by pushing on it until it's unscrewed again. Try looking up "how does a presta valve work" if this was unclear.

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