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You can afford to spec (shitty) Fox when you haven't spent a dime on R+D since 2011.
What bike?
But we’re not supporting Giant 😉 Also forgot Marin has storage on an alloy frame too.
I'm sorry, you are simply incorrect in your analysis. Virtually all antisquat comes from chain tension, and without it every vehicle with pivot-based suspension squats under acceleration.
You are right, a design with a pivot above the imaginary line between your CoG and the rear axle would be ridiculous and impractical, which is why every design relies on chain growth for antisquat.
Here are three pivot locations, the rear axle, and CoG. Both the low and the high solid red pivots are below that before mentioned imaginary line. You can see with the force arrows, if the rear wheel accelerates the bike+rider forward, the force vector between the forward acceleration and downward gravity acceleration drives forwards and downwards. The only way for the suspension to extend is for the pivot location to be above this line. This is the source of acceleration squat. The pink pivot location is the only one that will extend (but its in an impractical location).
Again, this is without a chain. The whole point of chaingrowth is to generate chain tension to overcome this. Again, if this were not so, where is the point where a high pivot is high enough to generate antiquat on its own without a chain?
Sorry for the delayed response, it was a while until I could watch the World Cup so I had to stay off Vital to avoid spoilers
I'm struggling to work out who is less wrong here - but yes a bike absolutely has anti squat (and anti rise) without a chain on it. The bike is being pushed by the swingarm which can pivot, so the response of the rider weight means it will likely try to tip one way or the other. The chain is just a second torque being added to the equation which can offset that moment. I think this needs its own thread
Until the front fell off.
In the webpage that shows the new stumpjumper alloy it also appears the "2025 demo", but I'm pretty sure that's the 2024 color scheme, does that means they are just going to try to push that model into 2025 and then release the updated one next year? After all the time that they've been testing the new one with ubb kinda sucks they went that road (if they did), same with the "new" enduro with just the udh upgrade and the thrilling new Matte black color 🥱
"I'm sorry, you are simply incorrect in your analysis. Virtually all antisquat comes from chain tension, and without it every vehicle with pivot-based suspension squats under acceleration."
No. At least not necessarily or not in all cases.
It's very well known that Red Bull has anti dive suspension geometry in the front (for braking) and anti squat geometry in the rear on their F1 car. At least they fine tuned it better than everyone else in the previous years, all the teams probably have it to some extent.
https://suspensionsecrets.co.uk/anti-squat-dive-and-lift-geometry/
Antisquat (and antidive) geometry comes from cars, what bikes use is just an additional component due to chain drive that is very rarely used with cars. It's not something that was developed for bikes specifically. It comes from the motorcycle world. If anything, it's just so much more important than with other vehicles due to the nature of power delivery.
Primoz, we are talking about bikes here 😁 so the question stands, does any bike out there has any antisquat with chain removed? If yes, how is the force generated?
All of them to some extent. Maybe even a negative one. The only problem is how to apply torque to the rear wheel without the chain to see this effect. One way is to use an electric hub motor for example, an ebike with a hub motor would have to be evaluated in both modes.
The response is generated because of the longitudinal force applied to the rear axle (reaction force because of the force in the contact patch) that is not in line with the virtual pivot of the axle member.
If the virtual pivot is above the rear axle, the response will be antisquat. Of it is below, it will be pro squat. How much response will occur depends on the height of the CoG, wheelbase, etc.
The chain tension is just another layer on top of this behaviour, specific to chain driven vehicles (motorcycles and bikes).
Yep, that's what I said.
No, I am correct in my analysis. You need to look at the rear triangle as an isolated system in its own right, it can absolutely produce anti-squat in response to acceleration-inducing forces being applied to the rear axle, without needing to be above the line between the rear axle and the CoG. A high-pivot bike with an idler can certainly produce anti-squat even with the idler placed directly on the main pivot.
Anti squat is just representation of how much the bike responds to acceleration, which there won't be much of without a chain but its a proportion, nor a magnitude. you could put the chain straight through the centre of a single pivot bike, and if that had a high enough pivot there would still be much greater than 100% anti squat. That's why very high pivot bikes put the chain above the pivot and still get around 120% AS
who said that??
Anyway, then go for the Xfusion(much better) and super R+D system 😄😄
Sorry, I don't get the point about "supporting" bike brands. This a discussion about bike features...then each one will decide what to buy.
Giant Trance X
https://www.giant-bicycles.com/us/trance-x-1
You guys are so serious about mountain bikes. I'm getting a good laugh this morning. 😄
I experience accelerative phenomena with no chain all the time. Allow me a few minutes to generate some graphs.
One can only hope that this makes it to production at the X0 level. That said, IMO the most overlooked flaw with the Transmission design is how rigid the direct mount design is and how that transfers forces into the cage. The rigitity of direct mount in conjuction with the stronger "clutch" means standard impacts to the cage are much more severe, resulting in a number of bent alloy cages and broken carbon cages. I have observed this among a group of friends I ride with and to date the damaged cage count is up to 7 or 8 among 4 people. This also seems to be an issue with other users based on some feedback I've read online.
Keeping this in mind:
1) What makes mechanical T-Type 'better' than the existing mechanical X01? Maybe the ability to quickly change the cage/clutch assembly?
2) Does the ability to withstand severe side impacts really matter, and is this ability lost in the mechanical design? IMO the cage will take the brunt of impacts on any derailleur.
The last piece of this that I've tried to figure out is how the mechanical version will 'slow' down shifts like the electronic version does in order to shift cleaner under load. Would this be designed into the derailleur, the shifter, or both?
Of the 7-8 cages your group has broken, do you know the distribution of what levels they were?
For the aluminum cages, I have a theory that the GX is the strongest, followed by XX, and the X0 is weakest.
The XX and X0 seem to bend at the big cutout. The XX looks like it’s forged while the X0 looks stamped.
The GX doesn’t have the cutout and seems to hold up better.
Distribution is 3 X0 alloy cages and 4/5 XX cages.
I can't confirm exactly where the alloy cages are bending but in one instance the cage broke around the bottom pully and bent as a whole.
As for the carbon cages the majority have broken at the hole used to mount the upper pulley. One cage completely lost the lower 'guard' around the lower pulley.
At this point the distribution of derailleur levels being used among my friends is now 1 X0 and 3 XX SL. Any original XX cages were replaced with the XX SL carbon cage/clutch assembly.
Regarding slowing down the shifts I’m guessing they’ll restrict the shifter to one click at a time like their ebike shifters, but beyond that I’m not so sure how they could slow down the shifts on a cable system.
crazy, I've only ever broken 1 Sram Derailleur and that was when gx 12spd first came out. since that time ive owned prob 50% of each brand (big S)
and ive broken a heck of alot of Shimano derailleurs.
Same with chains actually, never broken a Sram one but i've broken a few shimano ones.
I've got 2 Transmission GX and they've seen some heavy abuse and shift awesome still.
Like i said im pretty 50/50 split with what brand i get so more certainly not fanboying anyone.
Have you checked the chain length? If you are in the smallest cog there should be daylight above the chain to the top pulley. I see a lot sram bikes with a chain that's 1 link too long which puts huge strain on the cage as well as poor shifting. In the lower gears the chain is pulling straight through that top pulley so the cage cant rotate and will instead try to bend. It also be at the wrong angle to the cassette for smooth shifting. Check if there's room to take a link out.
Broke/bent an XO knuckle. At the time a replacement XO wasn’t available in Canada, and was 3 months out. Found one XX replacement. Shits expensive, I think it was $230.
I have yet to bend my XX cage but it is really flimsy. It appears that SRAM has moved the sacrificial part from hanger to cage. There is a solution however: https://cascadecomponents.bike/products/transmission-derailleur-cage
This cascade cage appears to be pretty burly and costs slightly more than OEM. Your friends should try going this route when they break the next one.
When I read this (welcomed) derailment I wonder if I even know bikes, I thought it was as simple as this; bike has two wheels, is funner with gravity, unless gravity is opposing direction of movement. Buttt it appears they are a little more complex than that.
I guess you could have a spring somewhere between the cable clamp and the mech. You push the shifter, it stretches the spring until the cassette rotates to a shift point and then the tension in the spring moves the mech.
Why is no one talking about this ?
This has been discussed previously but the TLDR is that T-type doesn't slow the shifts down or know when to shift, it's just a byproduct of where the ramps are in the cassette.
Smashing through gears on a mechanical T-type won't shift faster or slower, as the cassette is the same and there are only so many ramps to engage the shift.