OTB when climbing out of the saddle- Mtbr.com

1. OTB when climbing out of the saddle

This has happened to me twice while climbing out of the saddle on rooty singletrack.
I went out of the saddle and pushed my weight forward over the handlebar. Suddenly the bike just disappeared behind me and I faceplanted hard. It happened so fast I still held the handlebars when I went down face first. Luckily there was not a rock there. The force into the ground was so hard I started nose bleeding.

The importer had changed some parts (seatpost, saddle, a bit shorter stem) from the stock setup.

Could there have been some other changes to the geometry (that I'm not aware of) that could make the bike riskier to ride? If so, what kind of geometry changes would increase the risk of going OTB while climbing out of the saddle.

Anybody else experienced this?

2. You're climbing, out of the saddle with your weight forward....are you going OTB due to hitting a root or square edge bump? Were you going pretty fast at the time? I expect it's "operator error" and that whatever has changed, you'll adapt.

I'm on a newer geometry bike, steep STA, etc. and I have found that torquing up very steep climbs I no longer have to get as far forward. I noticed that, with my weight as far forward as I was used to, it unweighted the rear enough to cause a loss of traction. Reducing the forward weight bias a little has solved that problem.

3. Msu Alum: Thanks, yeah I was going really slow, I don't recall hitting a root or a rock. It just happened so fast - the bike slipped back under me in a millisecond (or so it seemed). I may have put my weight too far forward over the bars to get traction but I thought it was impossible to go OTB when climbing.

Bike is a 29er from 2013. 110/100 mm travel. 69.5 HTA. 74 degrees seat tube angle.

4. You're climbing and you leaned forward. Basic physics says that going OTB is what you should expect. You found the limit at which that happens.
Don't put so much weight over the front wheel in the future.

That's definitely happened to me more than once. Putting a big effort into a climb where precision is essential and hit something unexpected and BAM.

The solution is going to involve a lot of variables, but 99% of it is going to boil down to riding technique.

What specific model, year, and size is the bike? What non-stick parts are on it? How tall are you?

5. Fork setup, also fore-aft stiffness. If the fork binds instead of absorbs bumps, it'll pitch you over easy. Sometimes a stiff low-speed compression setup will help to do this too, but blowing through the travel and significantly steepening the HTA can also contribute.

6. Mack turtle: Thanks, yeah could be technique but I have not found many similar stories about riders going OTB uphill.

I'm 186 cm (6'1") and bike is a Ghost AMR Lector 2990 2013. Size 52.
I haven't been able to find reach and stack numbers.

Non-stick parts... I put GX Eagle on. And the shock is a Monarch XX but shouldn't matter in this case.

7. It's happened to me a few times. So now you know, you're not the only one.

8. Jayem - good point about the suspension. This is a short travel XC machine. Compressing most of the fork when leaning forward on the climb could steepen the HTA to a critical point where the front wheel just disappears under you.

Cheers!

9. Mack turtle: it's so good to hear that I'm not the only one especially since this happened during a marathon race!

10. Don't go so far forward. Check suspension settings. Pretty much covers it.

Happened to me once on flat ground, but what put me so far forward in the first place was the fact that my chain broke while I was laying down power.

11. Harold - thanks for sharing. That ought to be an awesome sight! :-D

I'll try to keep a bit back. Suspension settings were good.

Cheers!

12. I've done that too, twice i think. Once like harold with a chain break. You're pulling on the bars to lay down power... then you're feet can't support you and now you're pulling yourself over the front wheel. The fix isn't geometry or fork deflection or whatever... it's to have a calm upper body. Pull on the bars, but don't just strain at them like you're playing tug-o-war. Keep your weight centered.

13. Interesting conversation.
I can't visualize this happening, however it seems to have been a relatively common occurrence.

How I visualize a slow spped, steep climb with obstacles (roots/rocks) while having a terribly weight front-bias, I would expect the rear tire to slip out due to lack of weight over the rear, resulting in a tip over. Last thing I can understand how there is enough forward momentum to toss the rider over the bars an an uphill and no forward speed.

I'm sure it looks impressive, so well done on helping riding buddies see a 'funny'.

14. scottzg - I appreciate your thoughts and thanks for joining Uphill OTB'ers Anonymous. :-)
Seems like a good idea to keep weight centered and also consider the terrain before sprinting (in case of chain break). Better to fall on gravel than rocks.

15. Forest Rider: Yeah it's kind of funny. I was taken by surprise because it happened so fast. When my face hit the ground, I didn't even have time to let go of the handlebar. Full body weight on the face.

I started nose bleeding but luckily nose didn't break. Luckily there was soil there instead of a rock.

16. I’ve introduced 2 strong road/ tri riders to mountain biking. Both have crashed OTB uphill on technical sections their first time out. My guess is that they have so much power but haven’t learned technique yet. How to lift the front even while standing. I never had the problem my I came into mtb without enough power to make it up all the hills so it all progressed together. For what it’s worth both guys crush me on the road but I have to wait for them on the trail. No doubt they’ll be faster than me in a year or 2. Good luck I think it’s pretty common.

Sent from my iPad using Tapatalk

17. Autosmith - thanks for entering 2 more riders to Team Uphill OTB'ers! I also do Road - FTP is just over 300 watts, so that could be part of the equation. I'll think more about lifting the front more - even when standing.

Cheers!

18. I haven't otb'ed climbing but I've come close on my 26 hardtail race bike (but not racing) with steep head tube angle when I've hit a root or rock when carrying some momentum.

19. Originally Posted by Forest Rider
Interesting conversation.
I can't visualize this happening, however it seems to have been a relatively common occurrence.

How I visualize a slow spped, steep climb with obstacles (roots/rocks) while having a terribly weight front-bias, I would expect the rear tire to slip out due to lack of weight over the rear, resulting in a tip over. Last thing I can understand how there is enough forward momentum to toss the rider over the bars an an uphill and no forward speed.

I'm sure it looks impressive, so well done on helping riding buddies see a 'funny'.
There are I'm sure other factors involved. In my case, part of it was a sudden jerk to the front (after the chain snapped and some combination of my arms pulling my body forward, my body suddenly falling downward, etc). I'm sure part of it involved suspension compression, too, which will steepen the head tube angle and further promote you being thrown OTB. I had an OTB last fall where I was beginning a descent and not paying enough attention to myself (I was sweeper after a group of kids, and watching them instead). I hit a small bump in the trail, which combined to compress my fork a little and the deceleration pitched me forward (I was already a bit too far forward, admittedly). the combo threw me OTB.

Originally Posted by bjornart
Forest Rider: Yeah it's kind of funny. I was taken by surprise because it happened so fast. When my face hit the ground, I didn't even have time to let go of the handlebar. Full body weight on the face.

I started nose bleeding but luckily nose didn't break. Luckily there was soil there instead of a rock.

Also be sure to maintain your stuff. I was working in a shop that hosted big road rides several years ago. One of my coworkers was ON the ride (while I covered the shop that evening). He was in a fast group that night, and one rider who was notoriously aggressive accelerated into a sprint on a straight, flat stretch of road. His chain snapped when he stood up and pitched him OTB at over 30mph. He face planted into the road and took out my coworker and a bunch of other riders. He smashed his face and was gurgling blood. There were doctors and nurses in the group who attended to him and called for an ambulance. He ended up dying in the hospital that night. This guy was also known for not maintaining his bike very well, and others believe that his chain broke this time as a result of that.

VERY luckily you didn't face plant on a rock. The consequences of something like that are definitely not funny. The only sort of helmet that'll do much for this is a full face, though.

20. chazpat we are ready to welcome you to The Uphill OTB'ers team when you are ready. :-)
Thanks for sharing!

21. Originally Posted by Harold
VERY luckily you didn't face plant on a rock. The consequences of something like that are definitely not funny. The only sort of helmet that'll do much for this is a full face, though.
Glad you were okay after going OTB and sorry to hear about the rider who had a fatal accident because of chain break. That could have been avoided by maintenance as you say.

Yes, it's pretty uncomfortable to think about what could have happen if there was a rock there instead.

22. I had a similar experience, only my OTB trip was super slow, LOL.... I hit a multiple roots at the same time, and it tossed me forward enough to bring up the rear. It seemed like it took 30 seconds to land on my shoulder/face. It had to look hilarious if anyone saw it, and try as I may at the time there was nothing that kept me going over.

Mine was all technique and lack of momentum. Only time it has happened to me.

23. Upper body strength, bro.

24. It's likely been mentioned already, but insufficient rear rebound damping can be a factor.

25. I've done it once.

Once.

26. Funny thread: OP, GoPro it next time for us. 😂

27. Happened to me once but I was totally drunk.

28. Originally Posted by Lone Rager
It's likely been mentioned already, but insufficient rear rebound damping can be a factor.
THIS! This may be the explanation! Thanks so much Lone Ranger.
My bike came with a Monarch RT3 with the LL tune (Low compression, Low rebound). The LBS replaced it on warranty with a Monarch XX which only comes with the Medium tune. The rear suspension leverage ratio is 2:1, which means it needs a shock with Low tune. After getting the new shock with Medium tune I felt that the whole bike changed personality. For example the shock takes longer to compress, but shoots (rebounds) more forcefully.

Just before the climb, there was a ditch, about 1-2 meters wide. Now it becomes picture clear what happened:
1. I ride down in the ditch just before the climb. Rear shock compresses fully.
2. Being in a race, I stand up ready to climb. HR is in the red.

3. When I start climbing and lean over the bars, the rear shock rebounds forcefully at the exact same time.
4. These combined factors (leaning weight forward on the climb, compressing front fork = lower HTA and having the rear shock rebound fast) likely led to this strange OTB on a steep hill.

In the aviation industry, if you use a part meant for a 737 NG on a 737 MAX, you're asking for trouble in terms of safety.

29. Add me to the list. All it takes is exhaustion, bad technique and a mis-timed wheel lift. Next thing you know you've stuffed your front tire into a rock or root with your weight forward and too little forward momentum to save you from your mistake but just enough to send you forward!

30. OP, just a small physics lesson might help you understand what went wrong. You were out of the saddle, all your weight forward over the stem, your front wheel hit an obstacle, which caused your forward momentum to pause and weight shift forward, to try and get past this/going you applied more torque to the pedals, but most likely did not lift/unweight the front or move your weight back a bit. Therefor, your bike was basically stopped and not going to go forward because of pressure on the wheel, so when you applied force to the cranks, with the front wheel weighted, and back wheel unweighted, the bike pivoted under and up and threw you OTB.

So the lesson here is, when this happens again and you try to power over the obstacle, make sure you unweight the front wheel first before applying power, has nothing to do with bike geometry, stem length, it is purely operator error.

31. LyNx - thanks for your input. Normally I would agree with you if there was an obstacle there. But there was no obstacle. This is what made this happening so surprising.

If there was an obstacle there, I wouldn't be posting it here.

It may still be operator error though :-)

32. Originally Posted by bjornart
LyNx - thanks for your input. Normally I would agree with you if there was an obstacle there. But there was no obstacle. This is what made this happening so surprising.

If there was an obstacle there, I wouldn't be posting it here.

It may still be operator error though :-)
In addition to what I said above, front end flex is also a big one, narrow bars, with a long stem, with a dinky (32mm stanchion) longer-travel fork and narrow alloy wheels is going to bind easier when you hit something slightly less than perfectly straight-on. The flex then causes additional resistance that pitches you over. Things like shorter stems and wider bars (780-800mm) give you a lot more leverage to prevent this, making it harder to occur. Beefier stanchions like 34mm and stiffer modern wheels help too.

You can have these benefits without making it harder to climb, like more travel and a higher (stem/bar rise) would do.

33. this is great input Jayem. The fork is a SID RLT which I believe has 32 mm stanchions.
The wheels are pretty wide: AC Wide Lightning has 29.3mm inner diameter. They were set up tubeless.
Stem is 90mm and the bar is a 71 cm riser (which is a bit narrow by today's standard).

I see slacker angles and shorter stems on some modern XC race bikes. Seems safer.
Apparently some will have 68 degrees HTA (Like Bulls Wild Edge 2020).

To be precise, I didn't feel like I was pitched over the bar. It was more like the bike was slipped under me on the climb. :-)

34. Originally Posted by bjornart
To be precise, I didn't feel like I was pitched over the bar. It was more like the bike was slipped under me on the climb. :-)
This makes me wonder if the trail is haunted.,

35. Dirt junkie hahaha, that could be it!

36. Where's Ninjichor when you need him?

37. Actually, the bike slipped backwards (downhill) while I was stationary. It the bike was haunted, it would be mostly by gravity.

38. The bike is a Ghost, so that answers the "haunted" question.

That's a fairly steep HA and long stem, so the front bias might be a bit high. It's not "dangerous" and the obsession with slack head angles is a bit overblown these days. If you can manage a shorter stem, that might be helpful. Otherwise, it's just bad luck and bad timing for how you shifted your weight forward at that specific moment on that specific trail. Live and learn.

39. This 5% bike and 95% rider. I have gone climbing OTB a couple times and nearly have done it a few more times(handle bars to the gut). It was always down to technique. Either being a little sloppy or mis-timed front wheel lift. Fatigue makes it easier to be sloppy. It is not the bike's fault it is the rider.

40. I doubt it's risky to ride, as you indicated, unless some major compromises were made but you'd notice that right away.

Keep your balance weighted properly in that situation and make sure your front wheel clears any obstacles. Stay off the front brakes, too.

41. Technique, technique, technique... the sooner one can admit they need to work to develop their technical riding skills, the better. I have gone OTB WAY too many times in all sorts of scenarios including climbing. My problem stems from coming from being a pretty decent offroad motorcycle racer for most of my life, but then getting into mtbing in my 50's. On a dirtbike, you are always pushing your head forward over the bars to counteract the driving force of the rear wheel. One way you can describe it is that you "ride the front end" and the rear end is just there to push and will always follow.

None of that works on a mtb! Quite the opposite, you are quite often needing to get your weight WAY back on a bicycle. I am starting to work on this with dedicated practice sessions, as my brain still wants to get my head out over the bars which is a recipe for going over them in a hurry.

It was hard for me to get it through my thick skull that I need to spend dedicated practice time to learn the proper techniques. I only wish I had realized it much sooner so I'd be farther along today. Nonetheless, I'm getting there.

AM.

42. I've done it twice!
BOTH times it was just mis-timing the unloading of my front tire over a root/rock. 5mph, tops.

I've also done it on a step-up at ~3mph - where an over-zealous unloading of the rear tire combined with an over-zealous forward/upward lunge put my body past the handlebars.

It's probably the bike's fault.

-F

43. mackTurtle, JoePaz, Crankout, Attacing Mid, Fleas - I appreciate your inputs! It's quite reassuring that you have experienced something similar. I will work more on my technique.

95% rider and 5% bike... I still think the 5% bike could be the wrong rear suspension tuning (Medium) which makes the rebound much faster than the original tuning (Low).

Cheers guys!

44. It's hard for me to imagine how this is possible. I believe it because so many here say they've done it but it's difficult for me to envision.

Now I'll probably do it next time out though

45. Shock rebound is an issue when out of the saddle and moving slow?

Doesn't the shock need to actually compress for rebound to be a factor?

OP was way forward by his own admission, and apparently there wasn't any obstacle to bring the bike to an instant halt -seems less likely the culprit was rebound of the shock that for all intents and purposes wasn't active.

I'm sure I'm wrong, still can't visualize the situation despite those that have gone OTB uphill with very little momentum.
It almost seems feasible that OP spun the rear tire, throwing his weight even more forward, similar to the experience Harold had with a busted chain. That would cause a sudden bike stoppage (slipping rear tire).

I prefer to keep this as a "I read it on the internet" phenomenon before I want it to be life practice.

It is fun exploring the 'forensic' science of OP's misfortune. teehee

46. Originally Posted by Forest Rider
Shock rebound is an issue when out of the saddle and moving slow?

Doesn't the shock need to actually compress for rebound to be a factor?

OP was way forward by his own admission, and apparently there wasn't any obstacle to bring the bike to an instant halt -seems less likely the culprit was rebound of the shock that for all intents and purposes wasn't active.

I'm sure I'm wrong, still can't visualize the situation despite those that have gone OTB uphill with very little momentum.
It almost seems feasible that OP spun the rear tire, throwing his weight even more forward, similar to the experience Harold had with a busted chain. That would cause a sudden bike stoppage (slipping rear tire).

I prefer to keep this as a "I read it on the internet" phenomenon before I want it to be life practice.

It is fun exploring the 'forensic' science of OP's misfortune. teehee
Good question about the rebound. I believe it was a small ditch just before the climb. Besides, if you attack a climb from flat or slightly downhill you will have some rear end compression.

You could be right that the rear wheel slipped, creating the same effect as when breaking the chain. I did not register this however because it happened so fast.

Yeah, this is interesting forensics. It's like that with accidents -chain of events (no pun intended).

47. Originally Posted by Attacking Mid
Technique, technique, technique... the sooner one can admit they need to work to develop their technical riding skills, the better. I have gone OTB WAY too many times in all sorts of scenarios including climbing. My problem stems from coming from being a pretty decent offroad motorcycle racer for most of my life, but then getting into mtbing in my 50's. On a dirtbike, you are always pushing your head forward over the bars to counteract the driving force of the rear wheel. One way you can describe it is that you "ride the front end" and the rear end is just there to push and will always follow.

None of that works on a mtb! Quite the opposite, you are quite often needing to get your weight WAY back on a bicycle. I am starting to work on this with dedicated practice sessions, as my brain still wants to get my head out over the bars which is a recipe for going over them in a hurry.

It was hard for me to get it through my thick skull that I need to spend dedicated practice time to learn the proper techniques. I only wish I had realized it much sooner so I'd be farther along today. Nonetheless, I'm getting there.

AM.
This sounds like me when I first started riding mtb. I also came from a MX background. I started riding mtb in the early to mid 90’s and it took me a few years of many painful OTB crashes to realize I had a habit of being too far forward. In the early years I had to force myself to get my weight back on the bike. I never correlated it with riding dirt bikes for so many years, but it makes sense now. Forming a good habit on a dirt bike translates to a bad habit on a mountain bike. Most every other motorcycle skill translates over nicely with mountain biking.

48. Originally Posted by Forest Rider
It almost seems feasible that OP spun the rear tire, throwing his weight even more forward, similar to the experience Harold had with a busted chain. That would cause a sudden bike stoppage (slipping rear tire).
This has been my experience with 3 or 4 uphill OTBs. Usually the rear wheel slip is on a root, rock, or loose gravel and sometimes the front tire hits something at the same time. I ride hardtails almost exclusively, so have not had an uphill OTB caused by rear suspension.

49. Have any of you rode a full suspension 29er from 8 years ago? The geometries were horrible. I went OTB on that thing so many times I lost count. Most dangerous bike I ever rode. It tried to kill my wife, at slow speed, while climbing. Twitchy, unpredictable, mind of its own. Its the closest I've ever come to owning a horse.

50. I never went completely over but I banged my pubic bone into the stem multiple times resulting in big bruises when I would be climbing and loose traction on the rear tire and it would spin out and send me forward. I shortened the stem in my bike and it hasn’t happened since.

51. Or, you could just go full-Biker-Fox.

52. Originally Posted by watermonkey
Have any of you rode a full suspension 29er from 8 years ago? The geometries were horrible. I went OTB on that thing so many times I lost count. Most dangerous bike I ever rode. It tried to kill my wife, at slow speed, while climbing. Twitchy, unpredictable, mind of its own. Its the closest I've ever come to owning a horse.
My Ghost 29'er is from 2013, so 6 years old. What do you believe are the biggest differences in geometry compared to today's 29 geometry. What made your 8 year old 29'er dangerous and unpredictable?

53. Stupid long chainstays, overly laid back seat tubes, huge toe overlap, and a reach numbers that put all the weight over the steep, steep front end, all combined with little to no stack. Good for one thing and one thing only...seated climbing.

54. When I fall climbing is usually on my ass/back. It is hard to picture going OTB in that scenario. I have done it on flat terrain though.

55. Yes, I did, the first, 2007, Niner RIP9 and while it was definitely the flexiest thing I've ever ridden (nothing compares) and frame alignment was so far out of whack on a lot of them, but it climbed fantastic. I cleared climbs with ease that in the past on my 26" wheeled Giant Trance I had a 50/50 chance I'd clear and this with much less aggressive knobs (Kenda Nevegal StickE 26" vs WTB Nano 29") and in a taller/harder gear. Climbing was never a weak point of those early 29er, descending on the other hand wasn't nearly as nice as with bikes with the newer geo that started to show up around 2012 like my Prime.

Originally Posted by watermonkey
Have any of you rode a full suspension 29er from 8 years ago? The geometries were horrible. I went OTB on that thing so many times I lost count. Most dangerous bike I ever rode. It tried to kill my wife, at slow speed, while climbing. Twitchy, unpredictable, mind of its own. Its the closest I've ever come to owning a horse.

56. Unless you're fighting to keep the font wheel down you're too far over the front, and I would imagine rear wheel traction is minimal at best

57. Originally Posted by watermonkey
Stupid long chainstays, overly laid back seat tubes, huge toe overlap, and a reach numbers that put all the weight over the steep, steep front end, all combined with little to no stack. Good for one thing and one thing only...seated climbing.
How did I ever ride my 2002 hardtail 26er with 130mm stem and 585 wide bars 71 deg HA and rim brakes and not not die? Oh the horror.

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