Bike Control help please!

[Marcellus]

As some know I'm new to Mountain Biking and really enjoying it, getting more confortable every day I go out!!

Yesterday, on most descents my front wheel kept sliding out, rather like understeer in a car.

The bike is a Scott Genius MC20, I've got a Nobbly Nic on the front inflated to c35psi.

The tracks were above the tree line and a dry slate/shingle road/track with fist sized rocks.

Once ending in disaster; wheel slid out hit rock (larger than fist) stopped front wheel dead and I went over....picked up off the floor by a 70 year old bloke who was walking!!!!

SO what am I doing wrong??

[Gooby]

Are you loading the front suspension before the bend?

Is it just this surface or any other surface?

[Marcellus]

what is loading the forks before the bend??

I ran down, slowed for the corner and then turned...

[sjg]

A few potential issues:

- weight transfer / position. When descending there can be a tendency to shift weight backwards - that's a good thing when it's steep enough that there's a risk of going over the bars, but when cornering you need some weight over the front wheel for the tyre to work.

- braking on corners. The tyre can only do so much - lay off ANY front brake mid-corner. It's easy to apply a bit even if you think you're just covering the lever. Like in a car, get the braking out of the way first before turning in.

- tyre pressures. Some people run them way too high thinking they'll avoid pinch flats and they can let the fork deal with the bumps. While that's true to a certain extent, dropping the pressure a bit can let the tyre work much more effectively.

[Marcellus]

sjg said:

- weight transfer / position. When descending there can be a tendency to shift weight backwards - that's a good thing when it's steep enough that there's a risk of going over the bars, but when cornering you need some weight over the front wheel for the tyre to work.

could well be

sjg said:

- braking on corners. The tyre can only do so much - lay off ANY front brake mid-corner. It's easy to apply a bit even if you think you're just covering the lever. Like in a car, get the braking out of the way first before turning in.

unlikely as I tend not to "hover" over the front brake!!

sjg said:

- tyre pressures. Some people run them way too high thinking they'll avoid pinch flats and they can let the fork deal with the bumps. While that's true to a certain extent, dropping the pressure a bit can let the tyre work much more effectively.

What pressures do you think I should be running with?? currently I'm at 35psi!!

[JPJ]

Also the Genius MC can be a little twitchy at times, as it's an efficient marathon bike. As mentioned, it depends on your weight balance as much as anything else, the bike will need some weight on the nose to maintain grip. However the other likelihood is that you are leaning into the corner and the front end is washing out (understeer type effect). Your outside foot should be down, weight on the outside footwith your body leant over less than your bike. This way you are applying your C of G through your tyres, pressing them into the ground rather than leaning in and letting your C of G push the tyres out. Ideally you should be 'cocking' your wrist as well in order to bring your weight alittle further forward and allowing some flex in your arms. Have a look at the good guys riding (videos, magazine shots etc) and this will show you what I mean in a pictorial sense.

[Marcellus]

thanks for all of this.......I went out today back to the scene of the crime........before I went I reduced tyre pressure 5psi to 30 and made sure I kept my weight forward and didn't get the understeer.........