Pedalling efficiency on rocky tracks

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thelawnet
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Joined: 27 Aug 2010, 12:56am

Pedalling efficiency on rocky tracks

Post by thelawnet »

Any comments on how to maximise efficiency on an undulating rocky track? (Considering that it's basically a cinch to climb up tarmac, but a loose rock track of the same gradient saps your energy)

I notice the following:

* My (XCR) coil fork feels like it is entering a crater with every bump. Compared to friend's Epi(c/x)on air fork the difference is night and day, one feels like it is hitting holes, the other feels like it is actually working. I don't think this affects climbs so much?
* My basic Shimano hydraulic brakes are not very good and the levers are not very nice, which I suppose gives you less confidence on the downhill parts so makes you a bit slower, but not such a big deal on the ascents.
* Dropper seatpost? Hmm, I'm not sure if this is quite necessary unless you are going downhill on very extreme terrain? But it seems to be the trendy thing?
* Frame? Sorry no idea how much of a difference this makes, mine is quite cheap ALU.
* Weight? I think my bike runs about 13.5kg I'm more like 90kg !
* Wheels? Mine quite cheap. Not sure if it makes such a difference?
* Tyres? I have Smart Sam 27.5x2.25". They don't feel that sure in skiddy bits, but then this might be my lack of confidence to be willing to break bones ?
* Drivetrain? I have a Deore 3x10 with 11-36 and 40x30x22. In practice I can say I don't use the 40x except on smooth tarmac, so it effectively works as 30x22 with 11-36. In practice I doubt I use the 22/36 because by the time you get there, the actual bike speed is so slow it's hard to keep going in a straight line. I guess the most important factor here is anticipation, i.e being in the right gear ahead of time. I generally find I like to 'attack' to an extent to get it over with rather than going slower and then bringing the wobble factor into it. But maybe there's some other reason why you wobble.
* Full sus? Is this actually an advantage, if money is no object?
esuhl
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Re: Pedalling efficiency on rocky tracks

Post by esuhl »

I'm really no expert, but I've been casually riding my MTB on & off-road for a few years...

I'd say tyres make a BIG difference. Everyone will have their own preferences, but I really rate the Kenda Nevegal DTC (Dual-tread compound). They're insanely grippy in dry sandy conditions, over wet rocks, loose gravel; pretty much anywhere except thick wet mud.

They're great on the road too. Everyone will say I'm INSANE for using heavy, grippy tyres on the road -- the noise they make is a good indication of how much energy I'm wasting. Pedestrians can hear you coming! But I'm very risk averse, and they grip like no-one's business. When they lose traction, they do so gradually -- you can feel it happening and react to it, rather than the bike suddenly twitching as you totally lose traction without warning. And the DTC means that they don't wear out that quickly, either.

Also, I've also adjusted the "fit" of my bike quite a bit:

- Large flat pedals (to keep your feet firmly planted, help with your balance, etc.)
- Ergonomic triple-density handlebar grips (minimises vibrations, gives you a really good grip)
- A different sized stem, to change the height and reach of the handlebars, making the riding position more comfortable

I think... the more "solid" your connection points (handlebars, pedals, saddle), and your connection with the ground (tyres), and the more comfortable and ergonomic your position, the more "at one" with the bike you will feel.

Don't know if any of that helps? :-P
Brucey
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Re: Pedalling efficiency on rocky tracks

Post by Brucey »

Kenda Nevegal
Image

Schwalbe Smart Sam
Image

tyres make a big difference for sure; all tyres are a compromise of some kind. Any knobbly tyre is going to be slow on tarmac and will have iffy handling when you get cranked over; feel those knobbles squirm! But they are not meant for tarmac, they are meant for loose surfaces. The Smart Sam has one feature that is a token gesture to running on tarmac, and that is an almost unbroken line of knobbles on the tread centreline. This makes them run smoother on tarmac but it probably ruins the traction on certain surfaces too. A full knobbly (that is slow and noisy on the road) will help grip when climbing offroad for sure.

IME FS is not usually much of an advantage when climbing on steep loose surfaces. A particular pedalling style is, whereby you use SPDs (or similar) and pedal full circles (usually whilst seated) instead of stamping on the pedals once every time round, as it were. This also helps to prevent bobbing.

Suspension is a whole subject by itself and posh forks etc don't usually have 'much better springs', they usually have 'much better bushings and dampers'. Unless you spend as much as you can, you are probably buying something with rather crude damping. This doesn't make much difference when you are climbing steep loose surfaces, but it makes a difference at lots of other times.

Dropper seat posts are mainly to allow you to hang your backside off the back of the bike on steep technical descents, not for climbing. The best saddle position for climbing is not unlike the best saddle position for 'everything else' so won't prevent you from climbing well if you are set correctly.

The other thing is that you need a lot of power (as well as the right equipment and technique) to haul yourself up a steep climb; unless you can also (say) climb steep tarmac climbs in relatively big gears whilst pedalling smoothly, seated in the saddle, don't expect to climb well offroad, either.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
esuhl
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Re: Pedalling efficiency on rocky tracks

Post by esuhl »

Brucey wrote:tyres make a big difference for sure; all tyres are a compromise of some kind. Any knobbly tyre is going to be slow on tarmac and will have iffy handling when you get cranked over; feel those knobbles squirm! But they are not meant for tarmac, they are meant for loose surfaces.


Cranked over? Erm... what does that mean? :oops:

I initially went with the Kenda Nevegals as the ground round here is really sandy healthland, with a bit of forest. They're great off-road, but as I'm cycling on roads more, I should probably look at a different tyre.

Brucey wrote:The Smart Sam has one feature that is a token gesture to running on tarmac, and that is an almost unbroken line of knobbles on the tread centreline. This makes them run smoother on tarmac but it probably ruins the traction on certain surfaces too. A full knobbly (that is slow and noisy on the road) will help grip when climbing offroad for sure.


Ooh -- thanks for the tip. I'll have to give those a go. :-)
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foxyrider
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Re: Pedalling efficiency on rocky tracks

Post by foxyrider »

Fit some slicks for a few weeks, you'll really learn climbing technique then! When you can get up climbs on slicks then put some grippy tyres on and you'll romp up the climbs.

I used to mtb quite a bit and choosing the route up a climb is almost more important than anything else. If you can lock the forks out do so, select your gear early and pedal round smoothly, jabbing will cause loss of grip and momentum. I always found bar ends invaluable, they might not be 'in fashion' these days but IMV they are more use than ever wider bar widths.
Convention? what's that then?
Airnimal Chameleon touring, Orbit Pro hack, Orbit Photon audax, Focus Mares AX tour, Peugeot Carbon sportive, Owen Blower vintage race - all running Tulio's finest!
Brucey
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Re: Pedalling efficiency on rocky tracks

Post by Brucey »

cranked over = cornering hard

If I were running 50:50 on tarmac and (say) sandy heathland, I would (and have) chosen to run some kind of knobbly on the front, and a semi-slick tyre on the rear. The rear tyre takes most (typically about 2/3) of the load and makes most of the drag on tarmac; inflated hard the semi-slick will run quickly and smoothly on tarmac and the front sees less load so some knobbles are more tolerable. Knobbles in the front tread centre mean that, offroad, you still have good braking on the front wheel.

You don't need super rear grip to ride well on sandy surfaces, by and large; with the right semi-slick tyre simply deflating it a little will bring the side knobbles into play and give you some grip rather than none when you need it.
In practice you don't need super straightline grip in the rear unless you are on a steep climb, and with this setup the front tyre has similar or better grip than the rear under most conditions. This means that when the grip is limited the rear starts to slide around first which is better than the front washing out or something. Obviously if it is wet then there is just not enough grip but unless it is very steep then this usually just slows you down rather than causes you to stop or fall off.

BTW with any kind of knobbly front, I would not choose to run a tyre with no side knobbles at all at the rear, even if they were of no benefit when riding offroad. The reason is that, on tarmac, the rear could have much more grip when cornering than the front. This would be IMHO a good recipe for a bad prang.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
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Heltor Chasca
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Re: Pedalling efficiency on rocky tracks

Post by Heltor Chasca »

I won’t add anything other than practice makes perfect. And those Schwalbe Smart Sams are fantastic all rounders. I will ride for miles on tarmac to get to my off road routes without issue.

I’m glad you didn’t ask how to ascend on smooth, wet chalk like you find on the Ridgeway. I’m still working on that one. :D
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Mick F
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Re: Pedalling efficiency on rocky tracks

Post by Mick F »

It's the wet leaves on the narrow steep lanes that gets me wheel-spinning.
Mick F. Cornwall
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Re: Pedalling efficiency on rocky tracks

Post by PDQ Mobile »

A super smooth pedalling technique using as much of the 360 degrees as possible - cleats a big help here.
A high cadence.
These help deliver the power steadily rather than in surges which then tend to loose grip (and energy) in poor traction conditions.
thelawnet
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Re: Pedalling efficiency on rocky tracks

Post by thelawnet »

Thanks for the SPD observation, I think that should be my next step. Never have got round to them! Will look for some sandals (atm I mostly cycle in flip-flops :lol: )
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Gattonero
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Re: Pedalling efficiency on rocky tracks

Post by Gattonero »

thelawnet wrote:Any comments on how to maximise efficiency on an undulating rocky track?
....


Having ridden Mtb's since the late 80's, things have changed a bit with parts that have more performance, still the rider plays a big part in this.

As you've already noticed, suspensions can play a big part, and don't bother with cheap ones. Just don't.
Same goes for a full suspension. If you are dealing with very technical trails and steep downhills that require speed, that would justify a full-suspension. But it needs some good cash. Again, don't even bother with cheap full-suspensions, for the same money you can get a better specc'd hardtail that is going to be a lot better.

Same for the tyres, you have to choose something that fits the terrain you are going to ride. There's no scandal in having two sets of tyres, i.e. one for the dry and one for the mud, or one fast-rolling for the bridleways and a more knobbly one for the proper trails.

But above this, "efficiency" is achieved by the rider. Mountain biking is hard work, there's no escape from that.
You get all the body to work, the torso and the arms have to do a great deal balancing and pulling the weight from the front wheel when it needs to. Also, on hardtails, you have to learn to pedal while staying off the saddle, and this means to be just an inch away and not "on the pedals" like is done while climbing on a road bike.
All in all, I do recommend to integrate the MTb with a bit of Gym sessions, to strengthen the upper body. Spinning classes do help a lot as well, to get used in cycling off the saddle.
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...
thelawnet
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Re: Pedalling efficiency on rocky tracks

Post by thelawnet »

TBH I'm a bit scared of the downhill bits, I don't particularly want to hurt myself. I fell off a couple of months ago (edge of road interface with road at wrong angle) and my leg was mess up for about three weeks.

Although being scared isn't that good either. I stood on the brakes when going downhill on a giant pothole and ended up going head-over-heels (rather slowly, didn't hurt myself). In theory you need to go down everything at top speed, but it's not really my cup of tea. The issue is more that when that's the only way to where you are going (as is the case where I'm cycling in Indonesia) you need to develop at least some skill.
busb
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Re: Pedalling efficiency on rocky tracks

Post by busb »

thelawnet wrote:TBH I'm a bit scared of the downhill bits, I don't particularly want to hurt myself. I fell off a couple of months ago (edge of road interface with road at wrong angle) and my leg was mess up for about three weeks.

Downhill was always the scariest part of offroad to me but I always came off when going too slow rather than too fast - speed can save you from crashing rather than being the cause.
I used to watch the Bike Channel before it ceased, offroad in particular. What got me was the more talented the rider, the less likely they were to use cleated pedals! That is scary to me!
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531colin
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Re: Pedalling efficiency on rocky tracks

Post by 531colin »

esuhl wrote:..........I think... the more "solid" your connection points (handlebars, pedals, saddle), and your connection with the ground (tyres), and the more comfortable and ergonomic your position, the more "at one" with the bike you will feel............


Hmmmm, I'm not sure I agree completely.
Lots of responses about tyres and grip, but the way to pedal efficiently when the bike is bumping about all over the place is to separate the action of pedalling from the random movements of the bike.
The high-tech, high-cost way of doing this is suspension; the cheap, old-fashioned way is to set the bike up so you can pedal efficiently (in circles) with the bike moving about underneath you like a rocking horse. This requires the saddle to be much lower than is dictated by current fashion, and the handlebars set so you can distribute your weight between front and back wheels as required for grip, balance, and bumps.
Here http://wheel-easy.org.uk/uploads/documents/Bike%20Set%20Up%202017a.pdf is something I wrote about riding position, basically from the point of view of a touring cyclist, but the general principles are applicable to riding off-road.
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Gattonero
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Re: Pedalling efficiency on rocky tracks

Post by Gattonero »

The pedalling action off-road is not always direct to the suspensions or the gear. As long as the tyres and the rest of the bike do provide suitable safety for the terrain, is the rider that makes the difference.
There's no need to keep the saddle lower, on a cross-country or light-trail bike, the saddle is set for the right pedalling efficiency just like on a road bike. A Dropper seatpost is used when the terrain goes down steep, it does give an advantage in those situations, but not for pedalling.
It is the rider, by keeping the arms and the knees flexible, that will keep on and absorb the shocks working out with the body. Lowering the saddle on the flat (or worse, uphill) would only give some great fatigue. I never heard of "fashion" for the saddle height? Though is true there is people out there cycling with frames that really don't fit.
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...
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