Slipping on gravel
 

XT660R Everything standard. When I ride on gravel with a bit of loose sand in patches it feels as if the bike wants to slip. All I can manage is about 40km/H or so. Anything faster and it feels as if I am going to fall. Wierdest of all is it feels as if the front wheel is slipping out. The back is solid. Anybody got an idea? Tyre treads are still fine

Tyre pressure?..tyre profile?...I have Avon trailriders on my R,they are excellent on the road but have little traction on sand/gravel etc..

how deep is the gravel layer? is there some hardpack right underneath it?

Yes there is hard ground underneath the loose sand. The sand would be anything from 3 to 5cm deep with hard clay soil underneath. Between these areas it is fine. Doesn't seem to like the corrugations much either. I have noticed though that if I lean back so that there is more weight over the back wheel the bike is a bit more stable but not by much. I am sure that if large stretches of road where covered in loos sand I would get used to it, but there are just these small patches of about 2 to 3 meters long. You don't see them until you are in the sand and then the steering starts to get veeeery loose.

then don't lean over on the patches with sand/gravel.
stand up and grab the bike between the knees.
if it's that bad, maybe lower the rear suspension somewhat with less preload?
might be your bike is loaded too much up front.
for mx in deep sand,i also need to lower the rear (or up the front) to get more stability.
see how this helps out.

I am sure the bike is not setup correctly for my weight. I will definitely study up on that and see what I can do. Thanks for the help

have somebody else ride your bike and see how they feel.
it could be so many things... even loose spokes could cause alot of imbalance...

I know the previous owner turned the rear shock up as high (hard) as he could go so that the bike had a better stance. I am just waiting for a weekend when I am not busy spray painting or mowing the lawn so that I can adjust it a bit lower?softer

it's a 15 sec job ;-) it'll def make the difference in stability on gravel.

It looks like the previous owner turned the suspension down again before I took it over. I had a few minutes to spare today so I checked and it was set on the second lowest setting.

I weigh about 95kg (+-210pounds). What do you think I should set the level at to start with

front and back should sag about equal wheyou sit on it.
is it still very unstable on gravel?
is it the front or rear that's instable?

I don't have to work today so I will ask my wife to check what happens when I get onboard. have not adjusted it.


As I said I found out that although the previous owner had ridden it at max extension, he must have dropped it to 2nd lowest setting on the rear shock before I took possession.


It is the front that is unstable.



I will do the check and go for a test drive and let you know. Thanks for all your help.


The only "off-road" bike I have previously owned was a 80's Honda xl500 with twin rear shocks. Otherwise I have owned road bikes. This means I have pretty much no experience on setting up a off-road bike for gravel

if you increase the rear height then you put more weight on the front wheel. This can give you sharper steerring. On tarmac it may be helpfull but off road, I don't know but I would say at low speeds, off road, the tyres tread pattern, material & the pressure play a more important part.


Anything loose on a hard base surface is a recipy for danger (IMO) and I would treat it like black ice. Generally the front folds unless you use a lot of power to slide the rear intentionally. Learnt this from experience when I skidded on a freshly gritted road in a cold winter night!

I am sorted. My problem is I sit to far forward. Went to town today and traveled on the road that has been messing me around. Shifted my weight almost totally over the back wheel and I can drive at whatever speed I like. Took it up to 70km/H without a problem. Go figure.

Thanks for all the advice. Every bit has helped me to finally come to this conclusion. It feels very weird driving like this coming from totally road bikes where sitting so far back would mean to would slide out on a corner. I have lots too learn about this bike but I am having fun.

I am puzzled by your findings. You should not have to move far to the back for the bike be stable.
In fact I tend to lean forward at high speeds (80~105mph) to escape some of the wind blast and do so again when cornering fast.
In fact shifting weight to the rear, would make the steering go light & vague. (try it with a pillion



Rear sag at it's lowest can explain some of your problem. Have you checked the rear linkage. Could be the previous owner had changed it.

I am not traveling 160km/h + on gravel with soft sand. Good Lord. I think the fastest I have gone with this bike is 150km/H on the highway and the wind blast at that speed is not comfortable at all.



50Km/h or thereabouts is plenty fast for me on that road. The corrugations are horrendous at times. On tar I sit up front and bike is stable. On sand it seems to need weight over the back wheel so that the front can float over the sand. More or less the same position that you would take going down a steep hill.

And I got it even better. Sat for about an hour setting the chain and back wheel straight after a major cleaning episode. Seems as if it was just a hair off. I can now sit normal riding position and drive what ever speed i want to on gravel.

So the back wheel was skew as well.