# Rear wheel loosing traction up steep hill



## tigger (3 Oct 2011)

Hi,

I'm new to MTB but have ridden road bikes for 3 years now. The other day I was going up a very steep hill, hardpacked with some loose gravel on top and I was out of the saddle. The rear wheel lost traction and I pretty much came to a halt and had to unclip quickly! Tyres are Schwalbe Racing Ralph.


Has anyone got any tips what I should do in this situation?


Cheers


Tim


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## sheddy (3 Oct 2011)

You need to push your c of g backwards so that the rear wheel maintains traction. I guess MTB types would hang their bum over and behind the saddle


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## ColinJ (3 Oct 2011)

A hard packed surface topped with loose gravel is difficult to get a good grip on. If your tyres can't bite into the surface then they are always in danger of losing traction.

The best advice I can give is to remain seated (if you can), pedalling smoothly with your weight finely balanced between front and rear. If your weight is too far forward, the rear tyre will slide out. Too far back and you risk the front of the bike lifting. You can usually find a position that keeps the front down but still gives enough grip.

It is important not too mash the pedals round because that makes it more likely for a slide-out to occur.


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## jonnysnorocket (3 Oct 2011)

Not familiar with the tyres Tim, but normally its a matter of putting your weight over the back wheel (by getting back in the saddle) at the same time leaning fwd & keeping low to try to prevent a wheelie


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## tigger (3 Oct 2011)

Yeah that all makes sense thanks chaps. Just got to get the balancing act right then. Its funny because earlier in the same ride, similar incline, I stayed seated and started to get some front wheel lift. Hence the reason I got out of the saddle next time!

Its sooooo different and technical compared to road...

Any advice on getting the reach right on an MTB? Is it similar to road (i.e. golden rule the handlebar should obscure the front hub?

Cheers


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## dan_bo (3 Oct 2011)

Have you tried dropping your tyre pressure a bit as well?


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## Norm (3 Oct 2011)

The good ideas, IMO, are danbo's suggestion on the tyre pressure (within reason) and Colin's advice of sitting with a smoooooooooth and circular pedalling action. 

That's latter is a good general bit of advice off road, because much of the effort standing on the pedals will just be sucked into bouncing the suspension.


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## Tigerbiten (4 Oct 2011)

I get this all the time on my recumbent trike.
Not only off-road but also on-road if it's a bit wet/greasy/icy.

The trick I find is to try and keep the pedal strokes as light and as smooth as possible.


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## tigger (4 Oct 2011)

Thanks for the replies.

Tyre pressure, any recommendations? Mine are 2.1 front and back. Currently I'm riding a mix of road (to get out to trails) and then mainly hard-packed / light on top gravel. Any thoughts on pressure for this type of riding? I weigh 90kg if this makes a difference.

At the moment I've got them fairly firm, approx 40 psi rear and a little lower on the front.

Cheers

Tim


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## Cubist (4 Oct 2011)

Racing Ralph are great on dry hardpack, but I take mine off for winter and get something with a barred/ramped tread. I find Continental Slash have good traction on soft stuff. 

Reach on a MTB differs from bike to bike and genre to genre. The hugely varying geometry of MTB frames means no hard and fast rules for set-up. 

Technique is what you need. Once you get onto a steep climb then make sure you are in a reasonably spinny gear. As others said, too high a gear and you put too much torque down, so the tyre breaks away. 

I ride an XC bike with steep head angle and longish seatstays, so I tend to sit on the nose of saddle, and make sure I have no arm tension at all pulling upwards. I tend to bend my elbows outwards and push my chest towards the stem. In this position you are shoving your weight down through the seat tube towards the centre of gravity (BB), and by flattening your torso you're weighting the front of the bike to discourage lift.


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## MontyVeda (4 Oct 2011)

without reading the other comments... lower gear and keep your arris in the saddle


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## Cubist (4 Oct 2011)

40 PSi is a bit firm. I'd drop it to 35.


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## cjb (5 Oct 2011)

Cubist said:


> 40 PSi is a bit firm. I'd drop it to 35.




Interesting. I've always run my tyres on the firm side to avoid the occurance of snakebite punctures. Do you run both your summer and winter tyres at 35 psi?


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## Friz (5 Oct 2011)

cjb said:


> Interesting. I've always run my tyres on the firm side to avoid the occurance of snakebite punctures. Do you run both your summer and winter tyres at 35 psi?




I keep mine around the 30-35 psi mark too. Only ever got snakebites when I'd drop em into the high 20's.


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## cjb (5 Oct 2011)

Friz said:


> I keep mine around the 30-35 psi mark too. Only ever got snakebites when I'd drop em into the high 20's.




I'll give it a try, but don't you lose out on rolling performance on smoother tracks?


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## Friz (5 Oct 2011)

cjb said:


> I'll give it a try, but don't you lose out on rolling performance on smoother tracks?



It's always going to be a trade off. I set my pressure based on what the majority of the spin will be. If I'm strictly tarmac I'm up in the 40 area. 

Once I hit off road though I'll drop it down.

I'll trade grip on wet slimy roots and rocks for rolling performance any day. It just makes me pedal harder.


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## cjb (5 Oct 2011)

Friz said:


> It's always going to be a trade off. I set my pressure based on what the majority of the spin will be. If I'm strictly tarmac I'm up in the 40 area.
> 
> Once I hit off road though I'll drop it down.
> 
> I'll trade grip on wet slimy roots and rocks for rolling performance any day. It just makes me pedal harder.



I cycle mostly from home, which means I encounter lots of road between the off-road sections, so I run 40+ psi. I'll drop it down to 35 psi for a while and see if the trade off you refer to is worth it for me. I have to confess that the ride over the rough stuff is a bit sketchy !!


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## GrumpyGregry (5 Oct 2011)

learn to sit on the nose of the saddle, or to hover over it, whilst 'kissing' the stem, and also try tackling technical climbs in a slightly higher gear than you might think comfortable. Too many people climb in too low/spinny a gear for the conditions for ease when they would find it easier to climb at a sustainable discomfort tempo.


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## 02GF74 (15 Oct 2011)

yes nose of thje saddle.

it is a fine act of balance up a steep loose climb. you want more power so yhou stand up whcih means you have less weight on the back wheel.

is you sit on the saddle, there is less weight on the front so you flip over backwards.

a happy compromise is to lean forwards as much as possible but keep you backside seated on the seat of the saddle - you get your CoG forwards to prevent flips and have some weight on the rear for grip. it is harder to ride like that rather than standing so you would need a higher gear (larger sprocket) on the back.


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## spence (15 Oct 2011)

Pretty much as above, to help drop the CG keep your elbows down and tucked in. It is a balancing act, you may have to keep shifting the weight distribution and you feel slippage or lift. Practice........

Pressures 30 to 35psi, increases the foot print of the tread and allows it smother the loose stuff and find traction.


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