Rear wheel loosing traction up steep hill

[tigger]

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

 

[sheddy]

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

 

[ColinJ]

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.

 

[jonnysnorocket]

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

 

[tigger]

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

 

[dan_bo]

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

 

[Norm]

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.

 

[Tigerbiten]

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.

 

[tigger]

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

 

[Cubist]

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.

 

[MontyVeda]

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

 

[Cubist]

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

 

[cjb]

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?

 

[Friz]

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.

 

[cjb]

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?