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This is all a good reminder to revisit my bar roll/lever angle setup. I made a marked improvement with a bar roll forward but now I’m wondering how far I can push it…
Depends on what you want to change. Reach, stack or sweep angles? Then when you know what you want to change it also depends on the bar that you have and what it enables you.
At some point it might make more sense to change the bar altogether, the stem or both and play with roll.
I’ve been thinking about this lately, as a possible downside to higher rise bars ( >35mm) so really interesting to see some of the numbers put to it. Thanks @Primoz! It’s definitely something to consider with bike setup if you’re someone who has a preference of some roll in either direction.
I would warrant a guess that the roll is to help align the bars with his arms/upper body, because he’s not off the back of the bike or tucked in behind the cockpit, he’s standing tall and more so pushing down and into the front end, so the forward roll does help get his elbows up and out, keeping him in a strong position when he needs to weight the front.
Here’s a clip of Jackson’s mechanic talking about them trying the 50mm bar and the forward roll adding too much reach. As well as some other setup details.
This is going to be incredibly minute, and probably kind of pointless, but I'm thinking about how different ways to reach the same effective bar height and position can feel different, and change the handling of the bike. I have not done any real analysis of this, but think of the difference between having a slammed stem with a higher rise bar, and a stem at the top of the steer tube with a lower rise bar. Let's assume that the bar geo is identical other than rise, and the roll is positioned the same way, so in order to get the exact same relative hand position, we run a slightly longer stem to compensate for the head angle when it is at the top of the steer tube (for example the stem on a bike with a 64 degree head angle is about 13 mm farther back when 30mm higher up the steer tube). I have this idea that the longer higher stem lower rise bar would have a larger moment of inertia, and then would be more resistant to turning or slower handling than the slammed shorter stem with a higher rise bar. It's probably an incredibly small difference, but I bet it would have a perceptible difference in feel, more damped steering vs less damped with the exact same effective hand position.
I wonder if anyone is considering how you get there when it comes to their hand position.
I’m going to order a new medium Rallon soon but I can’t decide on 442 or 450mm chainstays. I’m a long chainstay fan for sure, but is 450mm reach and 450mm chainstays crazy!?!?!? (Ermagerd!). One of my most favourite bikes was the hp Range, one bike I had a tough time getting used to was a Pivot Firebird. The Rallon will be mullet.
I was going to make a long winded post (already is…), instead I will ask:
If you primarily rode fast DH trails, would you go with a rear end that matched your reach, is given the choice?
Interestingly, 450 reach / 450 cs is already a longer rear end than most people get.
Why can't cs be the same/longer than the reach?
Longer CS means you can have taller stack/bars and more upright position riding, which is rather nice when you get used to it.
What significance is there in the reach matching the chainstay?
Or, to put it another way, I hope your seat tube length will also match the same value. It's about as important.
Fair. A ratio of 1.75. Still the same question and concern.
Although given that I’m talking about one bike with a given head tube angle, reach compared to chainstay basically portrays the same meaning. But it’s not the proper calculation so I hear ya.
Totally. As I said, I like long chainstays. These are proportionately longer than man at people have access to. There has to be a limit, no?
Correct on both accounts, but at the end of the day stem length, handlebar rise, etc., all play a part. And judging by the discussions we have here, the weight distribution is what matters. Things get very nuanced...
As for what to choose, I don't think there are many people that can give an honest answer on what works and what doesn't, this is a new area to explore for the industry. But the few that have ventured that far claim the limit is still very much far away (judging by some 500 mm ca bikes out there).
On that note, I did the Stumpjumper EVO experiment on the friend of mine, short chainstay and full slack fork vs. long chainstay and full steep fork - 1,9 vs.1,8 front to rear ratios. He says there is a difference but I think he needs some more time on the 1,8 setup to fully get in tune. But the first ride was a marked improvement over the other setup. He was on the 1,9 setup for about a month (rides about 130 days a year).
I'm running a dreadnought v2 with 470mm reach and 470mm chainstay in mullet configuration.
It rips. Corners harder than any of my other bikes, makes traction where there shouldn't be any.
Running a relatively high bar position to go with that, 645mm stack, 30mm under the stem and 50mm bars. I'm 6' with long legs.
Requires a recalibration of riding style to a certain extent, but it's fast.
Western canada, winch and plummet style riding.
Interesting to play with it that way. I read about people going long front ends with steeper forks but I can’t wrap my head around it. I haven’t noticed a downside to slack hta.
@ntm95 do you notice any downsides? Of course I’ll get used to anything and I know it will crush fast trails, but were you a bit bummed with any aspect of it? (Manuals, breaking the rear loose, euro turns, etc)
The headangle is an undesired byproduct, the intention behind changing it is lengthening or shortening the front centre to get as much of a change in the ratio as possible - not only change the rear end but effectively move the rider forwards between the two axles.
If anything there is a point where on really steep stuff where it can pitch you forward a bit more, if your fork setup is marginal and you're going slow. But that's really steep, slow stuff that's full of steps, that most people don't ride regularly, if at all. And is exactly why everybody in arizona rides a bike with itty bitty chainstays and an air fork with 4 tokens in it, lol .
The time it takes to retrain from shifting forward and driving corners with your hips/shoulders to staying in the middle and driving with your hips/legs can also be considered a negative. The better the rider you are, the longer it actually takes to catch on. I can go back and forth easily enough now from a 1.9 bike to a 1.75-1.8 bike, but it's hard to break muscle memory to start with. I have a theory that fact does indeed contribute to the inconsistent reviews you see of bikes with lower ratios, like the dreadnought v2.
The advantages are that you're always in the right place. I find I can ride blind trails at speed with a whole bunch more confidence, and less mistakes. Gobs more grip, without having to go look for it with body position. Sounds lazy, but it can be a faster way to ride.
As far as manuals go, the ability to have a higher bar position helps, but you're not cheating/muscling the front end up. It's proper technique or no go. Not a bad thing really. Same thing for nose picking switchbacks, good technique, no problem.
Breaking the rear loose is harder at lower speeds, but you just go faster everywhere, and then it's easier :D . With the long rear end you can setup some pretty impressive scandis/drifts. Very predictable while doing so.
Years ago the trend in enduro was to size down, and riders went faster as a result. The interesting point was that riders were staying centered more on the smaller bikes.
The common thought process there was that the smaller frames were better on the tight stuff and a pro can deal with the hit in stability at speed. That's not untrue, but I think at least one of the positive contributing factors was that the smaller frames all had lower f/r ratios, due to the lack of size specific chainstays creating a consistent f/r ratio across all sizes.
I feel like I could have written this. I don’t view it as lazy, I view it as being able to ride relaxed, which is way more fun for me. I can ride so much looser and still make turns/redirect the bike without fuss. It’s made riding 10x funner
Thanks for the chatter. Medium with 450 stays ordered. I figured if it could be a lighter, more playful version of the Range, then it’s a huge win. The fact that it is mullet, lighter, and not high pivot but it starts with very similar length chainstays and has low AS, means I should like it a lot. Now to wait until spring…
I’m a fan of having competent, intuitive bikes that allow you to have fun while going really fast. Probably a result of where I ride and my skill level.
New Atherton is unrideable in any size under a 495 reach.
I wish they'd get someone who knows ANYTHING ABOUT BIKES to design these things! These fuckin' jokers have never ridden a bike fast or needed stability on a technical move. Just another brand who knows nothing but follows the crowd.
https://www.pinkbike.com/news/first-look-atherton-a150m-is-their-additively-manufactured-mullet.html
p.s. I don't actually feel this way. Just a little joke for the long chainstay crowd. The new Atherton A.150.M mullet has a 435 chainstay at 485 reach while the 29er has a 438 at 480 reach.
Is there a reason DW link bikes all seem to run short chain stays? I used to feel strongly about chain stays being a certain length, and then I got a bike with a shorter chainstay and longer reach than I considered ideal.. the bike is heaps of fun, so i stopped caring so much.
Weirdly, Dario referenced this on the PB podcast that I just this second listened to- he speculated that there could be pressure from DW himself that pushes bike companies into shorter chainstays. Something like them just working better with his designs. It was just speculation though I think.
My first thought honestly. There is something to be said for longer chainstays and leverage…
I think DW has a stipulation on CS length IMO.
There is the possibility the additional leverage could do weird things to the force chart. I don't have linkage anymore to model it. I do remember when we played around with overstroking DW bikes you always got a undesirable effect. But I almost always overstroke a horst bike and it's never an issue. Refer to my avatar. 210x55 native shock size, I think I went to 64mm stroke or something (2.5 inch) via removal of spacers and cane creeks way of recycling imperial parts on metric shocks.
Any of you other fellow tall people following this person? Some modern new age geo philosophy on XL sized bike
PB first look was in August: https://www.pinkbike.com/news/first-look-the-factory-cycles-tahr-goes-dh-or-enduro-derailleur-or-gearbox.html
Don’t think Vital had coverage.
Hey, thanks for the link! I somehow either missed that months back or forgot about and have been digging through/following along instagram for further information when provided. That link definitely helps explain and answer some of my questions about it. Rad bike! Diggin what he is doing geo wise for tall people!
That's just the stock geo, you can get longer chainstays by request I think
Long chainstays corner really well. They put weight on the front so you can drift/slide the backend around corners. Putting more weight on the front also allows you to use a taller front end. Large and XL bikes need 470-500mm chainstays to maintain that ideal 1.75 ratio-
Stack is a great starting point for re-engineering the mtb, but for stack to change you must change your position and riding style. The hype around goldstones season and technique has opened peoples eyes to a different approach to rider-bike integration. What’s the central premise of how a rider interacts with the bike? Is the rider controlling with the hands or with the lower body? What are we optimizing for? Uphill and flat pedaling or descending? Revisiting the central ideas and assumptions (maybe visiting them consciously for the first time) can give us a new lens to view the bike through. This won’t be for everyone and these new riding styles and ensuing bikes won’t work for everyone, but for the people who want to ride that way, it will be heavenly
"I was aiming at this part specifically:
"I think that as fc/rc approaches 2, the reach needs to increase to accommodate the rider’s balance."
On the face of it it says "make a long bike longer", frame wise. I didn't read it as specific for your case to change the reach by moving the bars.
Sure riding over the front is better on a bike like that. I said it works. You just need to be committed. And that's a mentality thing. You can't just say to someone "go ahead and try it". I moved to a smaller frame to shorten the reach from the old bike precisely because I can not ride over the bars.
On the other hand raising them helped me a lot.
Plus to ride over the front, I'd say bringing the bars a bit closer will work better than moving it farther away. You need to take into account the mental effects and what the rider does versus just moving the touch point. The end game is loading the front. Flexed arms will give you more power to weight the front than stretched out arms. And more finess. Thus why bringing the bars closer might have a more positive effect.
But, we are derailing, I explained all of this before in the geometry thread, etc. etc. "
@Primoz from an off topic in the other thread.
Length is from your interpretation, the off topic conversation was on high or low fc/rc ratio bikes. The hypothesis I shared is that there is a relationship between fc/rc ratio and reach, where I believe reach needs to increase as fc/rc approaches 2. I would extend that to suggest that reach and stack need to adjust as fc/rc increases. This is hardly different from what others suggest with RAD.
Again, talk is cheap - go and try to increase the effective reach and stack on a high fc/rc bike and see how it feels. You'll find that it doesn't feel like riding over the bars, it moves your center of gravity towards the front of the bike, weighting the front wheel more when in a neutral position. I had struggled riding an Enduro, increasing the RAD was an appropriate solution for me. For those already balanced on bikes like an Enduro, I think increasing RAD would make the rider feel more stretched out then they'd like.
Whether or not a specific rider can overcome the mental effects of changing their setup doesn't negate the idea that such a relationship might exist.
See above: "I moved to a smaller frame to shorten the reach from the old bike precisely because I can not ride over the bars."
Post a reply to: Modern Geo Talk: Chainstays, Stack, Reach, and Bitching About It