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Discussion Starter · #1 ·
Hey all,

Hoping you guys may have some ideas here.

SC Hightower LT
DPX2 27% sag around 310psi
Crankbrothers Stamp 11s

I've been running into this occasionally out on the trail and was wondering what could be the cause. I'm going to do my best to describe it.

Basically, if I'm going downhill and then into an abrupt steep uphill climb, my pedal will occasionally be flush resting on the ground as I go to pedal uphill. When standing in the attack position I lead with my left foot, so when this happens, it's usually my right pedal as I go to pedal that has no where to go. (pedal resting on ground) This is not a pedal strike, more like a pedal plant because I've already lost so much speed from the incline grade that I have to start pedaling and grind my way up it.

So in terms of trail shape, think like a \_/

I'm not going through all my travel front or back as evident by the rubber rings. Not bottoming out front or rear.

Any ideas? Thank you
 

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This place needs an enema
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Your bike, like most these days, has a low bottom bracket.

Combine that with big pedals and the down/up scenario and that's just what's going to happen.
 

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Hey all,

Hoping you guys may have some ideas here.

SC Hightower LT
DPX2 27% sag around 310psi
Crankbrothers Stamp 11s

I've been running into this occasionally out on the trail and was wondering what could be the cause. I'm going to do my best to describe it.

Basically, if I'm going downhill and then into an abrupt steep uphill climb, my pedal will occasionally be flush resting on the ground as I go to pedal uphill. When standing in the attack position I lead with my left foot, so when this happens, it's usually my right pedal as I go to pedal that has no where to go. (pedal resting on ground) This is not a pedal strike, more like a pedal plant because I've already lost so much speed from the incline grade that I have to start pedaling and grind my way up it.

So in terms of trail shape, think like a \_/

I'm not going through all my travel front or back as evident by the rubber rings. Not bottoming out front or rear.

Any ideas? Thank you
Your pedal gets closer to the ground when the suspension cycles.

Some people call that a low bottom bracket.

I don't quite understand. If your right food is trailing, and you are starting UP a hill after a trench crossing, the further back would be even further down to the ground. Seems like.

It's a little confusing how your right foot, behing behind, can't pedal. In a clockwise rotation you'd have to go 300 degrees clockwise before hitting the ground once it comes around in rotation.

Likely cause by my estimate. You're going through suspension travel as the ground comes up (the incline) and your feet are not level (as it feels maybe). During the suspension cycling it's just not the best case scenario.

As for low bottom bracket height, my full suspension has a higher bottom bracket than my hard tail. I almost never pedal strike on the hard tail (lower BB). Also, my older 26" hard tail is even lower and I almost never pedal strike there. The only thing difference is the full suspension has a variable BB height (suspension travel).
 

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Your pedal gets closer to the ground when the suspension cycles.

Some people call that a low bottom bracket.

I don't quite understand. If your right food is trailing, and you are starting UP a hill after a trench crossing, the further back would be even further down to the ground. Seems like.

It's a little confusing how your right foot, behing behind, can't pedal. In a clockwise rotation you'd have to go 300 degrees clockwise before hitting the ground once it comes around in rotation.

Likely cause by my estimate. You're going through suspension travel as the ground comes up (the incline) and your feet are not level (as it feels maybe). During the suspension cycling it's just not the best case scenario.

As for low bottom bracket height, my full suspension has a higher bottom bracket than my hard tail. I almost never pedal strike on the hard tail (lower BB). Also, my older 26" hard tail is even lower and I almost never pedal strike there. The only thing difference is the full suspension has a variable BB height (suspension travel).
Oh, and they are all 175mm cranks
 

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Low BB are common but it also sounds like you are bottoming out your suspension. 310 psi sounds like you are heavy and or having the EVOL make for a very active suspension.
 

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Discussion Starter · #7 ·
Your pedal gets closer to the ground when the suspension cycles.

Some people call that a low bottom bracket.

I don't quite understand. If your right food is trailing, and you are starting UP a hill after a trench crossing, the further back would be even further down to the ground. Seems like.

It's a little confusing how your right foot, behing behind, can't pedal. In a clockwise rotation you'd have to go 300 degrees clockwise before hitting the ground once it comes around in rotation.

Likely cause by my estimate. You're going through suspension travel as the ground comes up (the incline) and your feet are not level (as it feels maybe). During the suspension cycling it's just not the best case scenario.

As for low bottom bracket height, my full suspension has a higher bottom bracket than my hard tail. I almost never pedal strike on the hard tail (lower BB). Also, my older 26" hard tail is even lower and I almost never pedal strike there. The only thing difference is the full suspension has a variable BB height (suspension travel).
Yeah, I'm basically able to get 1 pedal stroke on the left foot since it's in the lead and then the right I'm pushing forward ends up on the ground.

Low BB are common but it also sounds like you are bottoming out your suspension. 310 psi sounds like you are heavy and or having the EVOL make for a very active suspension.
Even though the rubber rings aren't being pushed all the way off?

I'm 230lbs + 10-15lbs gear

There are no spacers per Fox. I've never bottomed out or use all of the travel so I haven't added any yet.

"2018, FLOAT DPX2, F-S, K, 3pos-Adj Evol LV, Santa Cruz, Hightower LT, 7.875, 2.25, CM, RM, Rezi A F M, Neutral Logo

This shock has a medium tune for compression and rebound (CM RM). "
 

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You don't have to bottom out suspension for your pedal to strike the ground on a hill. The ground is riding and your bike is sinking, as you approach the hill before your tires are on the same plane.
Especially considering the ground is closer when the pedal comes around the circle when not on flat land.

From what it sounds like, it's just what is going to happen and not a unique situation to you alone.
 

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TuTh rider
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Your bike, like most these days, has a low bottom bracket.

Combine that with big pedals and the down/up scenario and that's just what's going to happen.
I am 5 weeks out from a bad crash - torn rotator cuff and torn bicep ligament in my shoulder because my pedal hit a cut off stump on a trail that I am familiar with. The stump was hidden by some weeds - so cut fairly low to the group and I had a pedal strike and I went down - hard.

Overall I love my Hightower, - but I haven't been able to ride and won't for quite some time and I would like to not have to worry about pedal strikes, but it is tough for me to try to explain why to my wife why I want to get rid of my expensive bike for a new one. She is still fuming about me getting hurt in general. The low bb is the only downside of this bike for me, but I got bit hard this time. Good luck...
 

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And I'm out.
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I would suggest that at your mass with riding gear, you might want to consider running a standard volume air can instead of the large volume air can you have now. You'll have to re-set your sag, obviously. The other thing you might consider is a re-valving / re-shim / tuned shock for you since you fall outside of the industry "norms" for a mountain biker. But let's face it at 210lbs so am I.

That being said, the "trench attack" is not an easy one but it does work in certain situations. Pull a wheelie as you approach the other side and "land" both wheels at the same time on the other slope. You'll still have to grind up the hill, but that's trench warfare for ya.
 

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... it is tough for me to try to explain why to my wife why I want to get rid of my expensive bike for a new one. She is still fuming about me getting hurt in general. The low bb is the only downside of this bike for me, but I got bit hard this time. Good luck...
??? unless you get a bike without cranks and pedals you can always have pedal strikes. Shorter cranks and/or higher BB can reduce the incidence to a degree but not eliminate it. Stumps or rocks hiding in foliage along the trail will be an issue regardless. You gotta ride so as to eliminate the possibility of hitting them, or accept the consequences.
 

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There's a lot of things at play here.

1) SC LT is too linear in general so if you have the bike setup to absorb chatter and not give feedback to the frame/rider, you're going to blow through the travel easily.
2) You likely need a volume reducer in the shock. 310psi in the shock seems like a lot. My guess is that you need the .6 reducer minimum, and it appears your shock has none. It seems (since you mentioned that you "never bottom") that you don't have enough progression in the shock, and are running too much air pressure. The HTLT likes to be around 28-32% depending on your riding style.
3) You may be running the open mode adjust too open which isn't providing enough platform for the HTLT which has a lack of progression.
4) Your shock may have aerated itself and need a rebuild.
5) You may need to pay more attention to pedal stroke timing.
 

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I am 5 weeks out from a bad crash - torn rotator cuff and torn bicep ligament in my shoulder because my pedal hit a cut off stump on a trail that I am familiar with. The stump was hidden by some weeds - so cut fairly low to the group and I had a pedal strike and I went down - hard.

Overall I love my Hightower, - but I haven't been able to ride and won't for quite some time and I would like to not have to worry about pedal strikes, but it is tough for me to try to explain why to my wife why I want to get rid of my expensive bike for a new one. She is still fuming about me getting hurt in general. The low bb is the only downside of this bike for me, but I got bit hard this time. Good luck...
Before you sell that bike, make sure to measure and record the BB height so when you get back to shopping you can check height of the new, taller bike.

For reference -my 29er FSR BB height is 13.25".
Bottom of crank arm, not pedal, is 6" from the ground.

my 27.5+ Chameleon BB height is 12.5".
Bottom of crank arm, not pedal, is 5" from the ground.
Both bikes are equipped with Chester pedals -so pedal height is cancelled out as a variance between two bikes.

Discussing rough numbers, the 3/4" difference of BB height is relative to the 3/4" difference in axle center between the two wheel sizes. This would suggest the BB drop is very similar between the Specialized full suspension and the Santa Cruz hard tail.

I pedal strike far more often on the FSR than I do with the hard tail despite the 3/4" lower BB height on the hard tail.

I suppose it's just because I ride it differently and the low BB height is useless information to me because there are situations where I don't pedal over rough stuff as I'm too busy standing and coasting through.
Nah...that can't be it....
 

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So you're saying you're going into steep uphills with the left foot up and the right foot down?

Are you leaning the bike as you're pedaling as well? Or do you have clown feet? :)

Seams like your form is off, you should be coasting into the hill with speed to spare (from the steep dh) with your pedals level, once you start dropping some speed then pedal like a mofo.

Attack position should be off seat, centered with feet level in a horizontal plane plus or minus 15 degrees or so depending on what's going on.

That being said, perhaps you can get some video at some point? That would be my suggestion, I certainly wouldn't be blaming the bike when it could be as easy as a little technique change or suspension adjustment ie volume spacer or regular air can as stated above. Could even be the front suspension is not helping either, what year bike is that, what front fork?

It could also be that you are bottoming the rear shock, but if the stroke is shorter than the exposed stanchion it'll always look like you've got travel to spare when in fact you don't.
 

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Most of the stuff above is good advice, so I won't repeat, just add.

Another way to increase BB height is with tyres. Fit the tallest tyres you can.

I run a 29x2.6 hans dampf on the back of my Pole. It's the height of a 3" minion, but without the width (that I can't fit).

You are also talking about a dynamic move, don't know why no-one above is suggesting damping. Try maxing out the lsc and seeing how it affects the bike. I'm not hugely familiar with the dpx2, apart from it's a stripped down X2, which is a good shock.

Can you clarify your pedals are level?

Can you do a dynamic unweight as you go across the transition?

What about manualing across and transferring weight to fork on impact?

A few bottom out spacers may help the rebound if you preload.

Lots of things to try.
 

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Elitest thrill junkie
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There's a lot of things at play here.

1) SC LT is too linear in general so if you have the bike setup to absorb chatter and not give feedback to the frame/rider, you're going to blow through the travel easily.
This is a known issue with the "shock-actuated-by-top-linkage"-Santa Cruz models. This is why they've been slowly transitioning the lineup over to bottom-linkage driven like the V10 has been for years. With the top-driven, they have a wacky leverage curve and have not been able to fix without going to the different design. It goes regressive early on and does contribute to blowing through the travel. It should be far more progressive in the mid-stroke, where air-shocks are typically flat in the curve, but it's generally the opposite of this. The end-travel is progressive, which will add to the progressiveness of an air shock and prevent bottoming, but the mid-stroke is pretty wacky. Not crazy unique, there are lots of manufacturers with wacky leverage curves that aren't really suited to the shock put on the bike.

As stated in this thread, there are more than a few contributors, but this one is likely one of them.
 

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Elitest thrill junkie
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I pedal strike far more often on the FSR than I do with the hard tail despite the 3/4" lower BB height on the hard tail.

I suppose it's just because I ride it differently and the low BB height is useless information to me because there are situations where I don't pedal over rough stuff as I'm too busy standing and coasting through.
Nah...that can't be it....
It's important to realize most of the FSR designs will squat more as you pedal harder in rough terrain uphill, unweighting the front and causing the rear to sag even more. On some of the higher/more constant- AS bikes, they have lowered the BB for this reason, because they believe there won't be "more" pedal strikes because the rear end stays up higher, but this kind of creates a "BB height war" and other manufacturers follow suit to be the "lowest" and see what they can get away with. I think I had more on my old Enduro, but it's been a while now. This definitely is not santa cruz though, they maintain close to 100% until around 1/2 to 2/3rds of the travel and then drop off, so with that factor it should be pretty consistent.
 
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