Ask the experts

[unitofstuff]

My son has been riding some lift serve this year at Dear Valley - we both got FF helmets for it. They're so light, comfy, and well ventilated now there's no reason not to run one at DV.. He has a POC race and I have a Smith Mainline. Heck, there's soccer moms riding there with full faces and enduro bikes....

That said, I wear my trail lid most of the time, but I have a a thing for riding as much vert as I can in the heat with no shade on a bike with 115mm travel, so...

If your a smallish medium size head I have a 100% Trajecta I got at the spring sale that didn't fit me that well, new in the box if you want to try it on....

Funny enough, I have a small Trajecta sitting on my desk right now. Maybe great minds do think alike? I absolutely appreciate the offer though

I do have a Spec Gambit in the mail that I'm guessing I will like more, but I guess we'll see.

[Duffman]

Switched the drivetrain on the groms 24 in bike over to Deore 11 sp 11-42 from the 8 speed it came with , all working well .... But realized I installed the Shimano quick link with the arrow facing the wrong direction. FML. What to do? Technically as these are single use should I leave it alone, undo it and risk reconnecting it correct direction, or get a new one.

[toast2266]

Switched the drivetrain on the groms 24 in bike over to Deore 11 sp 11-42 from the 8 speed it came with , all working well .... But realized I installed the Shimano quick link with the arrow facing the wrong direction. FML. What to do? Technically as these are single use should I leave it alone, undo it and risk reconnecting it correct direction, or get a new one.

Reconnect and reuse. It'll be fine.

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[rideit]

I reconnect those things a dozen times in their lifetime, never had a problem.
They just want you to buy more.

[Dromond]

He wears a FF to race or race practice, but not to do mega exposed steep features on granite that has practically infinite modulus and zero impact absorption. I hope he changes his mindset, seems like a cool and nice dude.

Please explain modulus. I think it means the rock is very hard.

Around me I see that the vast majority of people with FF helmets pedaling up are one bikes. The protection is cool but what about fogging your eyewear all the time? Newer helmets too breathable for that?

[SchralphMacchio]

Please explain modulus. I think it means the rock is very hard.

Engineering term that is used to model out how much a material is expected to compress, bend, or stretch under a given load. Low modulus materials are soft, high modulus materials are hard.

[Whiteroom_Guardian]

Are there any chest HR straps that actually work? I've had two garmins and a wahoo and they all shit the bed fairly quickly.

[VTskibum]

Are you extra sweaty? I'm on year 6 of my Wahoo, admittedly pretty lucky from what I hear. Probably 6th battery and 2nd strap, but thing still works.

Another friend said that Polars are his favorite after going through the same struggle. YMMV

[grskier]

Engineering term that is used to model out how much a material is expected to compress, bend, or stretch under a given load. Low modulus materials are soft, high modulus materials are hard.

This is a great synopsis.

Here is one from a google search
Modulus of Elasticity
What is Modulus of Elasticity?
Modulus of Elasticity, also known as Elastic Modulus or simply Modulus, is the measurement of a material's elasticity. Elastic modulus quantifies a material's resistance to non-permanent, or elastic, deformation. When under stress, materials will first exhibit elastic properties: the stress causes them to deform, but the material will return to its previous state after the stress is removed. After passing through the elastic region and through their yield point, materials enter a plastic region, where they exhibit permanent deformation even after the tensile stress is removed.

Granite:
The elastic modulus varied from 11.1 GPa to 63.8 GPa.

Wood: Spruce pine: 6.89 GPa,

I'm guessing granite, like those boulders to be on the very high end of the range above. The bridge/wood lower as it'll bounce a bit before you exercise that trait of the material.

[BigHerm]

Was just shopping chest straps. DCRainmaker currently recommends Polar H10 or H9.

[Whiteroom_Guardian]

Yeah I'm really not very sweaty. I'll try the polar and see how it goes.

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[Andeh]

Are there any chest HR straps that actually work? I've had two garmins and a wahoo and they all shit the bed fairly quickly.

I use a Polar arm band one (goes on bicep) because the chest strap ones drive me nuts. No issues with it, been using it a couple years now.

[Meconium]

What other parts of the body are accurate for HR?

[Dantheman]

For sports, none.

[toastybroski]

After 1800 miles my rear rim is officially fucked. Hubs are DT 370s and seem fine. Shop wants me to spend around $300 to build a wheel around my existing hub. $150 for rim, $100 for labor, 50 for stans spokes and valves.

I really don't want to do that. Then I wont even have matching wheels. I also really done want to spend $1k for a nice wheelset. Anyone got any suggestions? 29in 148 boost with xd driver

[basinbeater]

You do actually have to wash the heart rate strap from time to time. I had a wahoo that lasted not very long, and a Garmin dual that has lasted much longer. Chest strap is far superior to optical wrist.

[rideit]

After 1800 miles my rear rim is officially fucked. Hubs are DT 370s and seem fine. Shop wants me to spend around $300 to build a wheel around my existing hub. $150 for rim, $100 for labor, 50 for stans spokes and valves.

I really don't want to do that. Then I wont even have matching wheels. I also really done want to spend $1k for a nice wheelset. Anyone got any suggestions? 29in 148 boost with xd driver

Light Bicycle has a great carbon set for that $$$. With 350’s.
I think S.C. Reserve has an alloy Wheelset for about that.

[Tailwind]

Find some take off XM1700’s for $300-$400 and call it a day. Just get a new set and sell the parts you’re left with from the old wheels. Get $50 for the hub for example.

It will likely be a nice upgrade.

After 1800 miles my rear rim is officially fucked. Hubs are DT 370s and seem fine. Shop wants me to spend around $300 to build a wheel around my existing hub. $150 for rim, $100 for labor, 50 for stans spokes and valves.

I really don't want to do that. Then I wont even have matching wheels. I also really done want to spend $1k for a nice wheelset. Anyone got any suggestions? 29in 148 boost with xd driver

[unitofstuff]

This is a great synopsis.

Here is one from a google search
Modulus of Elasticity
What is Modulus of Elasticity?
Modulus of Elasticity, also known as Elastic Modulus or simply Modulus, is the measurement of a material's elasticity. Elastic modulus quantifies a material's resistance to non-permanent, or elastic, deformation. When under stress, materials will first exhibit elastic properties: the stress causes them to deform, but the material will return to its previous state after the stress is removed. After passing through the elastic region and through their yield point, materials enter a plastic region, where they exhibit permanent deformation even after the tensile stress is removed.

Granite:
The elastic modulus varied from 11.1 GPa to 63.8 GPa.

Wood: Spruce pine: 6.89 GPa,

I'm guessing granite, like those boulders to be on the very high end of the range above. The bridge/wood lower as it'll bounce a bit before you exercise that trait of the material.

My engineering autism is twitching, so I've gotta clarify. Nobody has said anything that's wrong per se, but I want to expound on the concept.

Modulus, in the engineering context, is a general term of the relationship between stress (force applied) and strain (how much the material deforms). The different types of moduli (Young's, shear, bulk, elastic, etc.) are just that stress vs. strain measurement in different directions/axes. Might be pulling outward from opposite ends in tension, might be pushing inward from opposite ends in compression, etc.

You can definitely simplify it to "stiffness" or "brittleness" in most cases, but it is worth paying attention to what modulus someone is referencing. You're not likely to give a shit about Young's modulus when it comes to carbon bars on your bike, but the shear modulus is very likely to tell you something about their vibration dampening capabilities.

[grskier]

My engineering autism is twitching, so I've gotta clarify. Nobody has said anything that's wrong per se, but I want to expound on the concept.

Modulus, in the engineering context, is a general term of the relationship between stress (force applied) and strain (how much the material deforms). The different types of moduli (Young's, shear, bulk, elastic, etc.) are just that stress vs. strain measurement in different directions/axes. Might be pulling outward from opposite ends in tension, might be pushing inward from opposite ends in compression, etc.

You can definitely simplify it to "stiffness" or "brittleness" in most cases, but it is worth paying attention to what modulus someone is referencing. You're not likely to give a shit about Young's modulus when it comes to carbon bars on your bike, but the shear modulus is very likely to tell you something about their vibration dampening capabilities.

was trying to go for the owie when hitting your head on rock.

[BigHerm]

How can you tell if someone's an engineer?

[SchralphMacchio]

This started with me saying granite had *practically* infinite modulus and not expounding. I did not specify compressive modulus or really clarify what I meant - the key word was “practically.”

The main point was, we all can assume that if you fall onto a giant granite slab, it’s not really compressing or deforming, meaning it’s not reducing deceleration forces or absorbing any meaningful amount of the kinetic energy … Your body is taking nearly all of the impact energy if you aren’t well protected. Some of that energy is translated into rolling/ragdolling, sliding, friction etc … some of it goes to bones bending and breaking, flesh compressing, your brain momentarily flattening as it slams into the inside of your skull. At least in a falling slide a lot of the energy is preserved in kinetic form and not totally put into your body. But Yoann’s slide really only let his most of his forward and some of his downward momentum carry on while basically instantly stopping his angular momentum and putting that into his body.

If you are going to OTB without serious body armor, loam, ferns, moss, and forest duff is a better choice …

[toastybroski]

Find some take off XM1700’s for $300-$400 and call it a day. Just get a new set and sell the parts you’re left with from the old wheels. Get $50 for the hub for example.

It will likely be a nice upgrade.

Any good source for these other than fb marketplace?

[Gerome]

So I’ve upgraded my Santa Cruz Nomad V4 with a Fox 38 up front. What would the experts recommend for a rear shock? I think it requires a 230x60 shock length.


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[Gerome]

And what would the experts suggest I do to this specialized Epic from around 2010. I bought it for $1000 a few years ago. I like it because it’s a 29er that is about 25 lbs and my wife rides it, and it almost fits me too which is nice when I don’t want to ride the 37lb beast.

The front and rear shock need to be rebuilt. Is there a new shock I could fit to this bike with the old front skewer axle?

Any suggestions for a dropper post to make it less racer focused to make it more enjoyable for my wife to ride?




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