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Ryan Burney Added a reply to MTB Frame Compliance Analysis & Discussion

11/14/2024 2:52pm
This sounds cheezy so bear with me but I just wanted to say thank you for the great conversations here so far. I’ve already learned some new things and it’s got me pumped. If even one person learns something new from this, then this whole article was worth the effort. With discussions like this, we can spark great ideas and...

Ryan Burney Added a reply to MTB Frame Compliance Analysis & Discussion

11/14/2024 2:43pm
Great points. To add on, when you are running low spoke tension, you see the spokes lose tension above the contact patch. On a large side impact, this is where wheels can fold because the spokes don’t “catch” the rim when regaining tension as it takes off to the side. If the rim moves enough and has already begun to...

TheKaiser Liked a reply to forum topic MTB Frame Compliance Analysis & Discussion

11/14/2024 2:32pm
Henry at PB, and many others, including very good friends of mine who are bike mechanics/wheelbuilders, all seem to think that increasing spoke tension will increase the stiffness of a wheel, and vice versa. They all rely on some sort of "feel" related justification, and post hoc rationalization of why they think the tension is leading to what they think they are feeling. I am still unconvinced. I am not sure if you have ever seen it, but Damon Rinard (who has been a lead engineer at many bike companies) designed a rig back in the 90s to test the...
This forum topic has 135 replies.

carlinojoevideo Liked a reply to forum topic MTB Frame Compliance Analysis & Discussion

11/14/2024 2:29pm
Yeah the above trail was Teleonics from the upper dirt road before the "ski jump" to the parking lot. Bike set up: Steel front end(modeled after 23' Trek Session), stock aluminum rear end, Ochain, Dorado fork, DT 471 front rim 1.6 spokes, Crank bros DH carbon rear rim 1.5 spokes, CounterShox mounted on fork 800g and behind BB 600g, Conti Kryp tires 24/26psi. I only got a few runs in this day, then had a little get-off that stopped my riding for the day. So I didn't really test anything here, just trying to get some more baselines and data...
This forum topic has 135 replies.

Ryan Burney Added a reply to MTB Frame Compliance Analysis & Discussion

11/13/2024 6:23pm
Rad stuff. Can I guess the trail: Telonics? I don't know of any other DH trails there that have any G's besides a little bit on Silver Surfer. Great data! Any chance you have a full rundown of your setup? I think this is the perfect thread to show off your hard work on on the topic! Before conducting the...

carlinojoevideo Liked a reply to forum topic MTB Frame Compliance Analysis & Discussion

11/13/2024 6:07pm
Here is some data from riding my steel Trek in Southern California. Approx 2 minute run in Laguna. The rear axle showed 67% more lateral accelerations than the bb. (Negative is to riders left and positive is to riders right.) The rear axle showed that it twisted torsionally 35% more than the lower frame/bb. What does all this mean? Hahha, nothing really until I gather more data on the same trail, in the same conditions. But I’m starting to gather a baseline with a few frames. The problem is dirt conditions and trail style play a big load(literally) on what...
This forum topic has 135 replies.

Roryb Liked a reply to forum topic MTB Frame Compliance Analysis & Discussion

11/13/2024 2:57pm
Yes it is all give/take. Exactly like suspension setup. This bike (The Homer) gets pedalled as an Enduro bike, Whistler laps and then Prevost shuttle laps. For enduro and Whistler laps, I think the compliance is perfect. It eats rough and softens the harsh Whistler laps. Even with the firm suspension setup I run. Prevost is another beast though. It's perfect 85% of the time but there's some hefty hits and corners on that hill. And hitting those fast, you want to be fully comfortable that you know how the bike will handle. Those scenarios are like racing, so I...
This forum topic has 135 replies.

carlinojoevideo Liked a reply to forum topic MTB Frame Compliance Analysis & Discussion

11/13/2024 2:55pm
That looks rad! The front end and BB area look great, looks like an awesome job keeping that bb area from swaying. I could definitely understand that rear end being great in some areas but then moving too much in others. But like you said, it's all give in take. Personally, I'd rather have a soft compliant ride with maybe 1 or 2 areas that are "too soft", than an entire trail that is rigid and rattling my body. I'm working on a steel DH gearbox frame with @VesselBikeProject now. Yes I rode the Trek before, It was a much...
This forum topic has 135 replies.

carlinojoevideo Liked a reply to forum topic MTB Frame Compliance Analysis & Discussion

11/13/2024 2:55pm
That would be sick with the adjustable bridges. I did some testing on the Commencal V5 with them and it made a pretty big change in berms and G-outs. Could you share what CS and SS tubing you used on the rear?
This forum topic has 135 replies.

Ryan Burney Added a reply to MTB Frame Compliance Analysis & Discussion

11/13/2024 2:54pm
@earleb Dang that's a cool ride and cool idea too! Well done. Here are a few places you could buy back some stiffness: 1) seat stay bridge 2) increase the chain stay bridge length 3) add bracing to the swingarm here 4) and if you're really going for it, add a swing link like the older fury. Hope that helps!

carlinojoevideo Liked a reply to forum topic MTB Frame Compliance Analysis & Discussion

11/13/2024 2:45pm
I can definitely see why you think the rear end is compliant and maybe too much. Looks sick, though!
This forum topic has 135 replies.

Ryan Burney Added a reply to MTB Frame Compliance Analysis & Discussion

11/13/2024 2:44pm
It looks like an impact machine but it does seem as though Enve does measure displacement during impact somehow as they claim improved radial deflection during riding to improve comfort. It's cool stuff! Honestly I think those are the coolest wheels on the market right now. Someday I'll save up enough!

carlinojoevideo Liked a reply to forum topic MTB Frame Compliance Analysis & Discussion

11/13/2024 2:42pm
In this video by Enve, they show testing the wheels on a machine. Not sure if this is just a destruction test or gives them compliance/rigidity numbers. But to your post, I totally believe that 2x and 3x have different compliance, along with spoke tension, spoke diameter, spoke count, and rim choice. The combination is endless. This also brings me full circle because trail testing depends on the dirt type, rider weight, and riding style, which could all push a wheel to a different extent. I don't think we could sit here and say "this combination" is best for everyone...
This forum topic has 135 replies.

earleb Liked a reply to forum topic MTB Frame Compliance Analysis & Discussion

11/13/2024 2:40pm
This has been the first flex stays frame I have built. Previously there have been three linkage driven single pivots and a classic single pivot. The rear end sits at neutral at 40% travel with the shock removed.
This forum topic has 135 replies.

Ryan Burney Added a reply to MTB Frame Compliance Analysis & Discussion

11/13/2024 2:39pm
Just looking at the Orange, it seems like it mostly rolls, but the shock helps resist that. Since the shock is bolted to the flexing rear triangle, it acts like part of the frame, kind of like a strut on a car. This does put extra side load on the shock, but modern shocks are built tough and can probably...

Snfoilhat Liked a reply to forum topic MTB Frame Compliance Analysis & Discussion

11/13/2024 9:12am
There is a wheel review on a prominent mtb website where the reviewer attempts to educate the reader about why different wheels have different compliance. He uses the example that a 2X laced wheel, a 3X laced wheel, and a 3X laced wheel detensioned a small amount will all have different compliance. The rationale offered is theoretical and to put it plainly, i don’t think it’s interesting whether or not it’s good theorizing or poor. My question is what is the technical limitation in the way of building examples of these three wheels and measuring the compliance? Does the rig...
This forum topic has 135 replies.

Erwan_Ghesquiere Liked a reply to forum topic MTB Frame Compliance Analysis & Discussion

11/13/2024 3:37am
Super interesting thread ! I am currently riding a custom made steel frame, superenduro/freeride type. You thread comes just as I am considering frame flex on my own frame as I noticed some after riding it harder and harder. Basically I noticed that my frame flexes on high side load situations, mostly high G berms. Initially I thought it was tire roll, pumped them up super hard and that didn't solve the issue. Which lead me to consider flex in my wheels. I went from soft alloy wheels to stiff carbon rims and that didn't change much to be fair...
This forum topic has 135 replies.