Rear wheel losing grip when climbing

[lulubel]

I tried to tackle a new route on my cheap MTB today, and I was disappointed to find 2 hills that I couldn't climb because the back wheel was losing grip. The surface was a combination of dusty scree and large, loose stones.

I know to keep as much weight as I can over the rear wheel, and I know to maintain a smooth cadence (easier said than done when you're trying to get over large stones), so is there something else I was doing wrong? I tried in a very low gear, spinning quite easily, and I tried in a higher gear, but neither seemed to be better than the other.

Is it just that I've got a cheap bike/tyres?

Is it that I'm not heavy enough (47kg) to weigh the rear wheel down? (Maybe I should get rear panniers and put rocks in them!)

Or do I just need more practice?

 

[marzjennings]

What tyre pressure are you running and how wide are the tyres?

For loose stuff I run a 2.4 or 2.5" tyre at around 25psi, seems to hold ok in most conditions.

 

[lulubel]

What tyre pressure are you running and how wide are the tyres?.

Tyre pressures! That's it. I knew there must be something wrong. I don't know what pressures I'm running at because my OH broke the schraeder side of the track pump, and my hand pump doesn't have a gauge, but I can say for certain it's higher than 25psi. I wouldn't be surprised it it's twice that.

My tyres are also narrower than yours - 1.95 - which I can't do anything about at the moment, but I can certainly do something about the pressures.

Thanks.

 

[MontyVeda]

dunno if you're doing this or not, and i don't really know the terrain... but keeping my bum on the saddle helps with traction in spite of not feeling natural on some hills

 

[Globalti]

High pressures will cause your tyres to bounce off stones rather than roll easily over them.

Loose shaley rocky stuff is never easy to climb, momentum is your friend if you can get enough. Also as you suggest, weight distribution is crucial: too far back and the bike will wheelie and too for forwards and the rear tyre will lose grip.

 

[Red Light]

Tyre pressures will help. But a couple of other things. Its all about moving your weight around - forward to keep the front end from lifting and back to prevent the back wheel from spinning out. Its dynamic, not static and needs to be learnt. Couple with that is not spinning. You need to vary the power between pushing hard on the pedals to get over things and gentle maintaining speed to stop the rear wheel spinning out rather than trying to keep a constant speed. Then its all about reading the surface and feeling it through the pedals and adjusting the power on, off and in-between to get through.

 

[lulubel]

Thanks for the tips.

I think part of my problem is starting from a standstill. Both tracks in question start from either a road or wider track, and gradually get steeper and the surface gets looser as you go up them. Just as they reach what I think is their maximum steepness, there's a chain right across the track to stop motor vehicles going up there. The only way forward is to lift the bike over the chain, and once you've done that, you're trying to start from nothing. I tried walking up one of them a bit to see if the surface gets easier further up, but it doesn't seem to, and I was sliding around in my trainers, so it's pretty bad.

I haven't tried either of them since I first posted, but I will next time I get a chance. Will trying the tyres at very low pressures be OK with cheap wheels/tyres/tubes, or will I be at risk of punctures? (I've never had a tyre off the MTB, so I'm not sure how easy it will be.)

I'll also get in some more practice at controlling the bike on some easier trails because I know I struggle with getting my speed right, and keeping it on the line I've chosen. All the road biking and running hasn't done anything for my upper body strength, but I suppose that will come with time.

 

[al-fresco]

I've only been riding off-road for a couple of months and hill starts was a big problem for me. Ditching the OEM toe clips and fitting DMR pedals helped me to get rolling quicker and on slopes with poor grip I find that if I can use a higher gear that seems to help traction. I know I have my tire pressures too high but I hate pinch punctures - when I can afford to upgrade to tubeless I think that might be the way to go. And yes, it all gets better with practice.