Requiem for a Jaw

casualharbor9 said:... you really put that thing through the ringer 😍 !
Well... the specs say it’s a spring/elastomer combo. Not surprising it went soft in the heat. It bottoms out pretty easily too (70mm travel). It's firm enough, just a bit heavy at about five pounds... might be worth swapping in new springs and a stiffer elastomer if you plan on keeping it for a while...

From what I can tell: same deal. Feels as soft as a Manitou Relic (maybe I'm just too heavy for it). As long as there aren't any leaks, it's fine. Now I'm more worried about the tires. I pumped them up to max pressure a few days ago when it wasn't even that hot... (they've already blown out on me twice 😬 just sitting in the sun)

Then it would feel like a brick during the winter months!
Anyway, I've been eyeing a Marzocac Bomber for a while—an older model, obviously, but brand new condition. By the time I make up my mind, someone else will probably have snatched it up.

Dennis Collins38 said:So, basically, how much faith do you actually have in the critical components of a vehicle when your life is literally on the line?

Me? I'm pretty confident.
As long as some higher power doesn't start playing games with my steering, I'm good 😁
And if—and that's a big "if," don't quote me on this—things actually go south, then I'll deal with whatever issue pops up and head to a mechanic. That is, assuming it's a real problem; there are plenty of things I can handle myself just by grabbing my basic toolkit from the garage.

briskbison41 said:Yeah, pretty much.
Until some deity decides to start shaking things up on it, it's fine 😁
And if—and I'm biting my tongue here to avoid jinxing myself—if it actually does happen, then I'll deal with whatever mess occurs and head to the shop (assuming it's a real issue, because you can still fix certain things yourself with a basic toolkit).

The whole point is to THINK. I was considering getting a checkup over at Panch Ville, but that blasphemous crack caught up with me first.
Anyway, I mostly ride on asphalt, ranging from moderate to a bit aggressive. It makes me wonder what kind of abuse vehicles actually take when they're flying down a forest trail. Are the parts beefed up enough for long-term heavy use, or are you looking at a total overhaul every month? Seeing a buddy's relatively new Ali Bic snap on him made me seriously skeptical about aluminum.

I generally tend to ride pretty mellow; I don't really go out looking for trouble or riding aggressively (whatever that means to some people).
The only real reasons I see for a full overhaul are bearing play, swapping out brake fluid (if you're running hydraulics), replacing springs, and changing the fork oil (assuming those start knocking too). You also have to true the wheels when they get a bit wonky—though honestly, it’d be smarter to tighten things up more frequently regardless of how many turns are on the dial, because bolts can loosen up and cause that wobbling in the first place. Then there's the risk of cracks showing up in the frame, fork, or handlebars. Those are all pretty standard issues when you're hitting the trails. Basically, if you're doing DownHill or FreeRide, you're looking at it.

Out of everything I mentioned, I’d make it a point to regularly change the oil in my fork and brakes, and just handle the rest as needed whenever stuff actually starts breaking.

briskbison41 said:I usually ride pretty mellow, nothing too aggressive (whatever that means to some people).
The only reasons I see for a full overhaul are bearing cracks, flushing the brake fluid (if they're hydraulic), swapping out springs, and changing fork oil (if those start cracking too). You also have to true the wheels when they get wobbly—though honestly, you should just tighten everything more often regardless of how many turns are on it, because things loosen up and that's what causes the wobble in the first place. Then there's the risk of cracks appearing in the frame, forks, handlebars, etc. Those are all standard issues when riding through the woods. Basically, if you're doing DownHill or FreeRide...

Out of all that, I’d regularly swap the fork and brake oil, and handle the rest as needed if stuff actually starts snapping.

Some guy in the thread below had his wheel axle snap. What happens if a thru-axle bolt snaps while you're hitting a sharp descent in the middle of the forest? Who's actually checking and replacing that stuff on a regular basis?

Dennis Collins38 said:The guy in the thread below just had his wheel axle snap. It really makes you wonder—what happens if a thru-axle fails while you're hitting a sharp descent through some thick woods? Who is actually responsible for checking these things and swapping them out on a regular basis?

Honestly, getting a flat tire is a much bigger and more frequent headache, and since the end result is pretty much the same, I'd say... 🤣

jadetiger962 said:It’s a much bigger, more frequent headache if you just get a puncture, yet the end result is exactly the same, so... 🤣

Look, I've had flat tires before too, but a punctured tire is nothing compared to having no wheel at all.

... a spoke shouldn't just snap out of nowhere, provided you haven't cranked the tension to an absurd level. Most of the stress sits right on the hub, which, who knows, could just crack under pressure too... that’s precisely why manufacturers design specific heavy-duty components for certain disciplines. Just yesterday, I was squinting at the fine print 😁 on my fork and handlebars: WARNING! Not rated for downhill or freeride; XC only! So, strictly speaking, there shouldn't be any nasty surprises while riding on the pavement... (though, I did go ahead and build my rear wheel using reinforced downhill parts, just in case things go sideways)

... I honestly find it baffling how those delicate, finely threaded nipples on a wheel can actually hold up the combined weight of a rider, the bike, and those sudden, heavy impact loads... 🤷

Dennis Collins38 said:Personally, I’ve had my fair share of flat tires, but let me tell you, dealing with a puncture is nothing compared to the absolute nightmare of losing a wheel entirely.

When you're flying down a steep mountain pass, trust me, it doesn't really matter which one happens. Either way, you're going to end up eating dirt face-first.

Dennis Collins38 said:I saw someone on another thread dealing with a snapped wheel axle. It got me thinking about how sketchy things can get out there. What happens if you’re tearing down a steep, technical trail through the woods and your front caliper bolt just snaps mid-descent? Who is actually responsible for checking those parts and swapping them out regularly?

You’re talking about the core issue itself—the actual root cause and the underlying mechanics behind it.

Like jadetiger962 was saying, there’s a higher chance you'll end up with a flat tire while you're heading downhill, but honestly, the result is exactly the same—you're going to crash no matter which way you turn.

Honestly, it’d be better to just scrap the old one and pick up something new. They aren't even that expensive these days.
The only real headache is if we’re talking about an OEM wheel. If that's the case, you can't just patch it up; you’d have to have the whole thing rebuilt at a shop. You’d be looking at buying a brand-new hub, 36 spokes (matching the number of nipples), plus the labor for the truing. Honestly, though, I have no idea what the going rate is for a budget rebuild. Every single one of those components fluctuates in price depending on where you shop.

casualharbor9 said:I honestly don't get how those tiny, delicate-looking nipples on the rims actually hold up. You’ve got the weight of the rider, the bike itself, and then those sudden, heavy jolts from hitting a pothole or a curb—and you're telling me those little bits of metal aren't just snapping under the tension? It seems like a recipe for disaster. 🤷

One nipple might be strong on its own, but when you’re looking at a set of 36, the impact is on a whole different level. 😁

One single nipple is strong enough on its own, but when you're talking about a set of 36? The cumulative effect is much more significant.

... sure, it’s 36 (or maybe 32, or 40, or fewer, depending on the build...) times two wheels, but looking at them all together, I just don't see how they could support a 450-pound load... then again, appearances can be deceiving. It looks like...

Alright, 200 kg isn't exactly light weight 😬
I honestly have my doubts about how those nipples are going to handle that kind of load 😁

Sometimes I’m genuinely surprised by how much gear can actually take. There are times when I hit a pothole hard enough that my front rim takes a real beating, even with my tires running pretty soft
.
You really have to be careful with spokes; if you over-tighten them, they snap way too easily because they're just so sensitive. Honestly, it's probably better to just let a pro at a local bike shop handle the tensioning and wheel centering
.

... I said 450 pounds just as a rough estimate, but I suppose there's some added impact when you're slamming into an obstacle at full speed with your entire weight behind it... It’s entirely possible my math was a bit off...

I don't know... I might be able to dig up some info online regarding the approximate maximum load capacity for these nipples.
But then again, it really comes down to the specific type you're using; if they're those DT aluminum ones, I'm pretty sure they can handle a bit more weight.

casualharbor9 said:... I said 450 lbs just as a rough guess. I think that’s about where the load hits when you're slamming your full weight into an obstacle at full speed... I could easily be wrong about the math here...

You're way off. Dynamic loads are massive compared to that, and they aren't distributed evenly across all the spokes and nipples. The top spokes and the ones on the rear wheel near the hub take the brunt of it because of the torsional stress on the hub itself.

Dennis Collins38 said:You’re being way too optimistic. Dynamic loads are significantly higher than what you're thinking, and they aren't distributed evenly across all the spokes and nipples.

...here’s a little chart for you:



...according to this, the wheel can handle up to about 5000N (roughly 1,100 lbs) !?

The upper spokes and the rear wheel spokes near the flange take the brunt because of the hub's torsional load.

...maybe we could mitigate that by using patented asymmetric rims, or perhaps by lacing the spokes differently on one side...

Dennis Collins38 said:The upper stabilizer links take the most abuse along with the rear wheel links near the differential because of all that torsional load on the axle.

Where are you getting that from?
Give me some specifics here, because there isn't really any actual load being placed on those upper links at all.

Could you be a bit more specific? Because there isn't actually any load on those upper bars to begin with.

🤔 ... if you ask me, they seem to be taking the hit equally, since they're both under tension... 🤷

briskbison41 said:Where are you even getting that from?
Give me some actual definitions here, because there’s basically zero load on those upper spokes...

A spoked wheel works for a train, not for pressure. All the weight transfers to the hub through those top spokes since the whole thing is essentially hanging from the rim. That's why the wheel is so light yet incredibly strong. If you try to apply pressure directly to a spoke, it'll just bend without a second thought.

casualharbor9 said:...here's a little chart for you:

...according to this, the wheel can handle up to 5000N (about 500kg)?!

...maybe we could lower that by using some asymmetric rims (protected by a patent, obviously) and just weaving the spokes together on one side...

We're talking 500 kg of static load. If you're cruising at 22 miles/h (V=10m/s), you've got a mass of m=100kp. Now, hit an obstacle so hard that you stop the wheel over a distance of 10cm (S=0.1m) and calculate the force yourself. Acceleration is a=(VxX)/(2xS), and Force F=mxa
In the real world, you aren't stopping a bike in that tiny distance; you'll likely slam into some aluminum and slow down by, say, 3m/s, which gives you an acceleration of 90m/s². Multiply that by a 100kp mass and there's your 9000kpm/sxs. It's massive, but luckily it's just a momentary spike.