Long Reach or Slack HTA?

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Posted: Jul 4, 2020 at 21:02 Quote
Danzzz88 wrote:
TheSlayer99 wrote:
Danzzz88 wrote:


I do see your point and can see things from your view. I guess if you can show me a video example of someone going down a descent as steep as that around 45 degrees whilst staying centred on the bike that would help. Most videos I see of riders get off the back of the bike. My view is not only about getting you body lower for lower cog though, it's also because getting off the back of the bike is basically putting your body in a more vertical position above the bottom bracket, the position yoh would naturally want to be in if you simply stood on the hill with no bike. But you are saying the safest position is to basically be in a dive position?

Compare vital raw in the steepest parts of Val Di sole to the motorway of Leogang. Body position remains about the same in most riders. I’m saying ideal body position is a variation of the attack position, vertically on the bike, which evenly distributes impact load and allows more muscle groups to be used for supporting yourself. That’s what you see the pros doing and longer reach reinforces that for all riders. With relation to your hill analogy, do you lean back further or move vertically to gain more stability on the slope?

I guess the way I picture it in my head, imagine you could stretch the bike any way you want. Now imagine riding down the hill stretching forwards and basically the head tube steepens and reach increases but wh.eelbase stays the same. Now imagine pulling back on the handlebars and stretching the headtube backwards so you are more vertical and feet more inline with your hands. Given the constant being the wheelbase we can then determine what else geometrically gives the safest most optimal position to descend, and I would argue the second one.
Imagibe a rhombus tilted forwards with the leading edge at the top vs a rhombus with the leading edge at the bottom near the slope, which do you think is more geometrically stable going down hill? We are talking about having the top half of our body, the highest point away from gravity leant more forwards vs less forwards, and I can't see how the former is safer in any way. I am more than open to any videos proving me wrong though.

Watch any vital raw video and look at body position. I guarantee you won’t see any riders hanging off the back of the bike in just about every situation. You give up control for a feeling of increased safety, when you are losing safety with losing control.

Posted: Jul 4, 2020 at 21:14 Quote
TheSlayer99 wrote:
Danzzz88 wrote:
TheSlayer99 wrote:


Compare vital raw in the steepest parts of Val Di sole to the motorway of Leogang. Body position remains about the same in most riders. I’m saying ideal body position is a variation of the attack position, vertically on the bike, which evenly distributes impact load and allows more muscle groups to be used for supporting yourself. That’s what you see the pros doing and longer reach reinforces that for all riders. With relation to your hill analogy, do you lean back further or move vertically to gain more stability on the slope?

I guess the way I picture it in my head, imagine you could stretch the bike any way you want. Now imagine riding down the hill stretching forwards and basically the head tube steepens and reach increases but wh.eelbase stays the same. Now imagine pulling back on the handlebars and stretching the headtube backwards so you are more vertical and feet more inline with your hands. Given the constant being the wheelbase we can then determine what else geometrically gives the safest most optimal position to descend, and I would argue the second one.
Imagibe a rhombus tilted forwards with the leading edge at the top vs a rhombus with the leading edge at the bottom near the slope, which do you think is more geometrically stable going down hill? We are talking about having the top half of our body, the highest point away from gravity leant more forwards vs less forwards, and I can't see how the former is safer in any way. I am more than open to any videos proving me wrong though.

Watch any vital raw video and look at body position. I guarantee you won’t see any riders hanging off the back of the bike in just about every situation. You give up control for a feeling of increased safety, when you are losing safety with losing control.

Yea to be fair you are right, in those videos they look pretty centred on the bike, what that says about their reach numbers I don't know but they are not hanging off the back that's true.

Posted: Jul 4, 2020 at 21:20 Quote
Though this one of Loic Bruni, when things get really steep around 2:40 he basically has his ass on the rear tyre.

https://youtu.be/Lw9vLv-HqA8

Posted: Jul 4, 2020 at 21:23 Quote
Danzzz88 wrote:
TheSlayer99 wrote:
Danzzz88 wrote:


I guess the way I picture it in my head, imagine you could stretch the bike any way you want. Now imagine riding down the hill stretching forwards and basically the head tube steepens and reach increases but wh.eelbase stays the same. Now imagine pulling back on the handlebars and stretching the headtube backwards so you are more vertical and feet more inline with your hands. Given the constant being the wheelbase we can then determine what else geometrically gives the safest most optimal position to descend, and I would argue the second one.
Imagibe a rhombus tilted forwards with the leading edge at the top vs a rhombus with the leading edge at the bottom near the slope, which do you think is more geometrically stable going down hill? We are talking about having the top half of our body, the highest point away from gravity leant more forwards vs less forwards, and I can't see how the former is safer in any way. I am more than open to any videos proving me wrong though.

Watch any vital raw video and look at body position. I guarantee you won’t see any riders hanging off the back of the bike in just about every situation. You give up control for a feeling of increased safety, when you are losing safety with losing control.

Yea to be fair you are right, in those videos they look pretty centred on the bike, what that says about their reach numbers I don't know but they are not hanging off the back that's true.

I’ve listed the reach numbers of multiple riders previously in the thread. Bike checks usually list bike size.

Posted: Jul 4, 2020 at 21:28 Quote
To be honest 480mm reach at 5'11 doesn't seem that far fetched, the dudes at Geometron had me at 5'8" on a 485mm reach and the next bike I intend to get has 475. My previous bike was a medium SB6 with 420.

Posted: Jul 4, 2020 at 23:07 Quote
Danzzz88 wrote:
ski-n-bike-da-east wrote:
Danzzz88 wrote:
Long reach is mainly a way to get longer wheelbase whilst at the same time enabling steeper seat tubes and better climbing performance.

By having a longer reach bike compared to a shorter reach bike, the idea (at least this is what i think) is that you are still able to get behind the front wheel and maintain more weight on the front wheel, which aids in any kind of cornering. For instance, if you had two bikes with the same head tube angle, stack, and all that stuff, when you are shifting your weight to the back when riding something steep on the short bike, your center of gravity will be further away from the front wheel, and closer to the rear tire than the long bike. This is because the longer reach enables you to shift your weight around, but still be mostly over the bottom bracket, and closer to the front wheel, allowing you to weight each wheel efficiently while maintaining stability.

I thought about this myself but ask anyone that rides a bike at least with too long reach and they will tell you they suffer from front wheel washout, therefore not enough weight on the front tyre. You can simplify this from a physics point of view. Forget the rider can move around for a second and just concentrate on static forces. Take either a horizontal plane or a decline, it doesn't matter which and set two scales with a plank across them. Keeping the bottom bracket and rider position constant move the front scale further away from the rider mimicking longer reach. The reading on the scale will now be lower. A longe reach stops you getting far back on the bike but also makes it harder to weight the front wheel. Basically both extremes are reduced but the so called 'sweet spot' is increased or less affected by body position. Basically the rider had less control over how the bike is weighted that is the affect long reach has. Very good riders usually opt for bikes on the shorter reach end of the spectrum, some like Richie Rude even size down.
Long reach is good for noobs but for riders who are very talented shorter is more agile. Imagine it's like an F1 car vs a Ferrari. Your average Joe can probably drive a Ferrari faster than an F1 car simply because they can't control or have the speed to gain enough downforce in the F1. But a talented driver will be miles faster in the F1. Long reach basically gives you more margin for error. The trade off is less say over what the bike is doing at the extreme ends of the scale and requires larger movements from the rider to have a noticeable affect to how the bike is balanced.
My privateer p4 thinks otherwise, I ride tight switchbacks easier and guess what, faster than my previous bike. It doesn't matter what the scales show when the bike is static, bike and rider is a dynamic combo, it's not a racing or a rally car that ypu are fixed in the buggy seat straped with 5/6point harness. You don't have to hang on the back of the bike when you ride steeps, your hands being extended actually limits ypur ability to control the bike and simultaneously balance your body position. Stay up right and focus where you want to go, let the bike work. Long reach bikes need equally long chainstays, a 515 reach bike with 420 chainstays won't ride as good as One with 450+ the short chainstays being closer to bb and the front wheel so far out gives a very rear wheel biased ride which results in the front wheel washouts, long chainstays help put more weight on the front. I know it's counterintuitive but it works, when you drop bad habits and commit to new riding habits. Ask me how I know.

Posted: Jul 5, 2020 at 0:22 Quote
TheSlayer99 wrote:
Danzzz88 wrote:
TheSlayer99 wrote:


You really dont sounds like you are willing to see other views on this, or have read the points I’ve given. You start with a lower CoG with a longer reach. You don’t need to make as drastic movements with a longer reach to maintain control. To maintain control with a longer reach you only need to make vertical movements. There is never a point regardless of how long a reach you have where your normal range of motion contacts the top tube. With shorter seat tubes and longer dropper posts this becomes even less of a problem. There is never a reason unless you want a playful bike to have a shorter bike. With a longer reach you are naturally in a more stable position where you can maintain more control in a centralized position on the bike. This is in terms of bio mechanics, basic geometry and physics.

I do see your point and can see things from your view. I guess if you can show me a video example of someone going down a descent as steep as that around 45 degrees whilst staying centred on the bike that would help. Most videos I see of riders get off the back of the bike. My view is not only about getting you body lower for lower cog though, it's also because getting off the back of the bike is basically putting your body in a more vertical position above the bottom bracket, the position yoh would naturally want to be in if you simply stood on the hill with no bike. But you are saying the safest position is to basically be in a dive position?

Compare vital raw in the steepest parts of Val Di sole to the motorway of Leogang. Body position remains about the same in most riders. I’m saying ideal body position is a variation of the attack position, vertically on the bike, which evenly distributes impact load and allows more muscle groups to be used for supporting yourself. That’s what you see the pros doing and longer reach reinforces that for all riders. With relation to your hill analogy, do you lean back further or move vertically to gain more stability on the slope?
last time I saw someone leaning back going downhill landed on his ass really hard, it's like skiing, you lean forward to gain speed and balance not backwards, you cannot beat gravity, you go along with it and hope for the best! Smile

Posted: Jul 5, 2020 at 3:26 Quote
For me it's good that a lot of manufacturers are offering longer reach, as long as they offer a good range of sizes. Being a taller rider, it's much easier nowadays for me to find a frame that fits. On older bikes I always felt cramped (most only went up to L, with 450-460mm max reach) and it was much harder to be centred. With modern geo most riders have the option to downsize and run a longer dropper. The downside is there are fewer frames to suit shorter riders in a lot of manufacturers ranges. I think the brands that are still offering shorter frames (and smaller wheel size) for diminutive riders at the lower end of their range have got it right.

Posted: Jul 5, 2020 at 7:14 Quote
Well I am 5'8 and have only seen mixed opinions on the matter. What I do know though is I used to ride an SB6 with only 420 reach, I can't say I had any problems standing but seated even with that shortish reach I always felt hunched over, to the extent I would sometimes get lower back stiffness and come off the bike in pain in my lower back. Also I could never weight the front wheel and ride agressively seated, I always had to float over the saddle, stand up or hang over the handlebars to get any decent amount of load into the front tyre. People now recommend a 450 plus reach for people my height and yet seated I had a problem with 420. You could say yea but now seat angles are steeper, but they don't seem steep enough, some of the bikes I am looking at in my 'recommended' reach range have even longer Effective top tube lengths than my SB6 and that was already bad enough seated even with a 35mm stem.

Posted: Jul 5, 2020 at 7:26 Quote
adespotoskyli wrote:
TheSlayer99 wrote:
Danzzz88 wrote:


I do see your point and can see things from your view. I guess if you can show me a video example of someone going down a descent as steep as that around 45 degrees whilst staying centred on the bike that would help. Most videos I see of riders get off the back of the bike. My view is not only about getting you body lower for lower cog though, it's also because getting off the back of the bike is basically putting your body in a more vertical position above the bottom bracket, the position yoh would naturally want to be in if you simply stood on the hill with no bike. But you are saying the safest position is to basically be in a dive position?

Compare vital raw in the steepest parts of Val Di sole to the motorway of Leogang. Body position remains about the same in most riders. I’m saying ideal body position is a variation of the attack position, vertically on the bike, which evenly distributes impact load and allows more muscle groups to be used for supporting yourself. That’s what you see the pros doing and longer reach reinforces that for all riders. With relation to your hill analogy, do you lean back further or move vertically to gain more stability on the slope?
last time I saw someone leaning back going downhill landed on his ass really hard, it's like skiing, you lean forward to gain speed and balance not backwards, you cannot beat gravity, you go along with it and hope for the best! Smile

Hanging off the back of the bike going downhill can be a great way to pump some extra speed from the transitions. Mountain biking is dynamic, not always about the most balanced position...

Posted: Jul 5, 2020 at 11:02 Quote
Tall rider on too short bike vs short rider on too long bike. Tall rider was only 2 seconds slower riding a bike too short. But short rider was 5 seconds slower riding a bike too long.
What is most scary is the size of the XL Neil tried 3 years ago is not far off what riders his height are being recommended to buy now. This is obviously not clear cut at all.

https://youtu.be/jkAbI0aWHxc

Posted: Jul 5, 2020 at 11:27 Quote
Danzzz88 wrote:
Tall rider on too short bike vs short rider on too long bike. Tall rider was only 2 seconds slower riding a bike too short. But short rider was 5 seconds slower riding a bike too long.
What is most scary is the size of the XL Neil tried 3 years ago is not far off what riders his height are being recommended to buy now. This is obviously not clear cut at all.

https://youtu.be/jkAbI0aWHxc

The seat tube on the xl sanction is almost 100mm longer than the seat tube on the medium strive. That’s all I put it down to.

Posted: Jul 5, 2020 at 11:31 Quote
TheSlayer99 wrote:
Danzzz88 wrote:
Tall rider on too short bike vs short rider on too long bike. Tall rider was only 2 seconds slower riding a bike too short. But short rider was 5 seconds slower riding a bike too long.
What is most scary is the size of the XL Neil tried 3 years ago is not far off what riders his height are being recommended to buy now. This is obviously not clear cut at all.

https://youtu.be/jkAbI0aWHxc

The seat tube on the xl sanction is almost 100mm longer than the seat tube on the medium strive. That’s all I put it down to.
.
But he is riding stood up, the saddle wasn't in the way, it more seems that a tall rider can cope with a shorts bike agility but a short rider can't manouver a bike that is cumbersome. The only thing I will say is that it didn't seem particularly steep terrain and Neil was doing an awful lot of pedalling.

Posted: Jul 5, 2020 at 11:46 Quote
Danzzz88 wrote:
TheSlayer99 wrote:
Danzzz88 wrote:
Tall rider on too short bike vs short rider on too long bike. Tall rider was only 2 seconds slower riding a bike too short. But short rider was 5 seconds slower riding a bike too long.
What is most scary is the size of the XL Neil tried 3 years ago is not far off what riders his height are being recommended to buy now. This is obviously not clear cut at all.

https://youtu.be/jkAbI0aWHxc

The seat tube on the xl sanction is almost 100mm longer than the seat tube on the medium strive. That’s all I put it down to.
.
But he is riding stood up, the saddle wasn't in the way, it more seems that a tall rider can cope with a shorts bike agility but a tall rider can't manouver a bike that is cumbersome. The only thing I will say is that it didn't seem particularly steep terrain and Neil was doing an awful lot of pedalling.

The saddle was very much in the way. Because good body position relies so heavily on being able to move vertically above the seat, seat tube length is very important. By your argument, dropper posts don’t need to exist because in your normal range of motion the seat wouldn’t get in the way high posting. My last bike was an xl stumpy Evo 29. My current bike has the same chainstay length, 40mm more reach, a 2 degree slacker head angle and most importantly; a 70mm shorter seat tube. I’m significantly faster on my current because I have an extra 70mm of drop on the dropper post to move around the bike with. If the stumpy didn’t have such a long seat tube it would’ve been fine to this day and I wouldn’t have gotten rid of it. Seat tube length plays a huge part in bike feel. My current bike which feels perfect felt cumbersome and sluggish when I got rid of 30mm of drop from the dropper post. If I could run a 200mm dropper post, I’m sure I could ride a bike with at least 500mm of reach with no problems.

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