Why did I lose traction and fall on my scooter?

I'm traveling Vietnam by a purchased gas scooter. Typical Yamaha scooter with smaller 16" wheels.

Yesterday while riding in the mountains I lost traction and took a bad fall. I am unsure about why exactly I lost traction but here is the story.

It was a bit wet out as it just rained a small amount, temp about 60F or 15C. I was riding straight doing about 40KPH to 50KPH, not very fast. There was a section of the road where the surface was worn away and it looked to be mud and gravel or a lot of small rocks and dirt inside this shallow hole in the street. While riding my scooter over these scattered rocks I very slightly hit the brakes while the bike was completely straight, probably applying more rear brake to slow my speed a little to be safer. As soon as I just touched the brakes the bike just lost traction and fell to the left side. I of course also fell and rolled and have bruises and scrapes all over, even though it is hard to walk from a swollen knee I should have a full recovery. I couldn't believe that the bike was mostly OK other than a few scratches and was still drivable without any problems. I thought it was finished in the drop.

What I don't understand is I thought you were pretty safe when traveling straight. I know the tires on my scooter were street tires and were not knobby.

Why did the bike just slip out on the wet dirt and rocks so easily while traveling straight? Would applying just very little braking cause this? Was it mostly because of the rain and it wouldn't have been an issue if it was dry?

Thanks, I'm trying to determine why I lost traction so easily here. I definitely don't want to take another fall like this over concrete.

Here is a picture of the scooter, and me sitting on the side of the road in pain after the fall, wish I had knee pads on, I always wear then back home with my electric bike. What I am sitting on is similar to what I drove over in the center of the street, kind of muddy rocks. The bike just slipped on this stuff like it was ice.

Rear brake will make you skid you can usually recover. Touch the front brake even a little when it's slick and you can be down before you know what's going on. Things you just don't do while on two wheels when you are entering or on a slick spot are change direction, decelerate, accelerate or apply the brakes. Get past the slick first if you can. If you can't anything you do had better be very gradually and even then you can be down.
I crashed big rime and did the superman slide in the snow a couple years back so know it can happen in the blink of an eye. Good you are not old and already broken cuz you don’t heal as fast.

One brake or the other must have locked up. Could have been the rear, but I'll bet it was the front one. With the slick surface and street tread, it happened with less brake pressure than usual.

But in slick enough conditions, even just a tiny bit of steering input could have the same result too. You didn't do that, so I'm betting the front wheel locked up for just an instant.

Interesting, you know the front brake is so sensitive on the bike. It is ridiculously sensitive. I think that may have been the case here that I locked the front wheel.

The rear is a drum brake and not a very good one because it hardly locks up. It also isn't hydraulic like the front brake. I can barely ever lock that rear tire up even if I squeeze it really hard.

Even if you didn't apply it, a slightly dragging front brake could cause what you describe.

I hit a patch of spilled Diesel fuel many years ago on a moto. My front brake had been dragging just a bit and it put me on my ass in a flash.

'hope you're feeling better soon!

Light rain is the most dangerous time to ride. Heavy rain washes the oils from cars off of the road but a light rain just forms a slick. The gravel is the only thing that may negate this.

riding on gravel with street tires is unpredictable at best and may have had nothing to do with the brakes at all but simply an uneven spot that caused the bike to lose traction and flop over.

As an example, I had wrecked my R1 doing some stupid street racing when I was younger. I had just spent $1500 replacing all of the plastics and took it for a ride on a winding mountain road on Palomar mountain in California. There are scenic overlooks and I decided to stop and take a picture. The road was paved but the scenic overlook was gravel. I was traveling at around 10 mph on the gravel and was going strait. It seemed like someone just pulled the rug out from under me. For no reason, the bike just flipped over. I was going so slow when it happened, I did not even fall I just ran to a stop and looked back at my now scratched up brand new plastics.

Shit just happens on gravel. At the time, I had a professional M/C racing license from WERA but that did nothing to help me.

Here is what you have to do in the future to TRY avoid this. When approaching gravel slow down first and then release the brakes. Get up off the seat and put your shoulders over the handlebars. focus on keeping the front wheel pointed in the direction you want to go and don't worry about the rear wheel; it will fall into line once out of the gravel. Do not accelerate and do not decelerate if possible. Keep the throttle steady.

Gravel sucks and it is probably nothing that you did wrong. Street tires don't help but lets face it, you were riding on the street so what else would you have on the scooter.

Hope you feel better.

Like peddles in the ocean, I wonder if gravel often walked would loose it's sharper edges. That gravel might even of been deposited there ready rubbed, though you do look rather high up.

The great thing about automatic transmissions and both brakes on the handlebars is that you can go slow with both feet gliding the pavement to catch yourself in questionable-traction situations. That technique doesn't work if you're going too fast, however.

Pea gravel is effectively ball bearings scattered on the road.

The very low center of gravity on those scooters means that when they start to fall over, gravity has them on the ground faster than your reaction time. once they start to go, they are gone.

If the mud was slick, and you even breathed on the front brakes, I would expect that to put the bike on it's side faster than you can blink.

2 things would help. 1, get rid of the slick tread on a bike that needs to ride on unimproved roads. 2. The front brake is for crashing. don't use it on a scooter except on clean dry roads.


Glad you're all right. Dude, that ride sounds epic!

Drunkskunk said:

The very low center of gravity on those scooters means that when they start to fall over, gravity has them on the ground faster than your reaction time. once they start to go, they are gone.
…

Click to expand...

Based on my extensive winter riding on a moped in Iowa, I'd say the higher the center of gravity, the quicker they wash-out. Mopeds with a low COG were really easy to 'catch'. Enduro style with high ground clearance and a higher COG were more 'tippy'.

You'll get the most traction by maintaining your speed. During braking, you are spending some of that traction to slow you down. Limited traction already due to poor conditions added to using some of that traction to slow you down, lateral traction ran out and you slipped. The rocky surface doesn't help as it will tend to pitch your wheel since the scooters don't have a huge contact patch. How much air did the tires have at the time?

I guess the unexpected can happen at any time, hope you are feeling better.

Drunkskunk said:

The very low center of gravity on those scooters means that when they start to fall over, gravity has them on the ground faster than your reaction time. once they start to go, they are gone.

If the mud was slick, and you even breathed on the front brakes, I would expect that to put the bike on it's side faster than you can blink.

2 things would help. 1, get rid of the slick tread on a bike that needs to ride on unimproved roads. 2. The front brake is for crashing. don't use it on a scooter except on clean dry roads.


Glad you're all right. Dude, that ride sounds epic!

Click to expand...

I see there is debate about the low center of gravity but I was doing some thinking about how quickly this fall happened, it happened so fast and I was down in an instant, like you say. Braking definitely had to have something to do with it because the instant I touched the brakes, even though it was so light, the bike went down.

What sucks is that I do a lot of crazy off road riding with my raptor ebike, all sorts of different types of terrain. I also drive sometimes 30+ MPH over gravel roads and my raptor never slipped out once, not on wet roots or even wet grass. I even test brake all the time over rough conditions like gravel and dirt without any issues. In a way you can say that I am a very experienced rider when it come to rough conditions yet this scooter slipped out like it was on ice.

I wonder if the tires are the reason my raptor never loses traction, I run a knobby 3" tire on the rear at a lower PSI and a knobby bicycle tire up front. I generally don't drive when it is wet out although in the forests I drive in it is sometimes damp and I have no issues.

Another thing that sucks is I almost always wear knee pads when I ride my ebike, reason being is that I figure the knees are the most likely to get hurt in an accident. I wear them under my jeans and am very strict about wearing them. I know just how injury prone they are because I took a couple of slow speeds falls without them and the knees seem to get hurt very easily. Of course when I don't have them here in Vietnam, of course I fall and the most hurt part in the fall is my left knee which is swollen. I am able to walk on it and it seems to be getting better, but I hope I didn't damage anything internally. There are no signs that I damaged anything internally but because it is swollen and hurts to the touch I can't be sure of anything.

What is also interesting is I remember Chalo was commenting that helmets don't matter that much and that you naturally protect your head during a fall. What I find interesting is that even though I rolled on the ground my helmet didn't get a scratch on it. Not saying that you shouldn't wear a helmet, it is just surprising that I didn't once touch the ground with the helmet, kind of like what Chalo mentioned.

You can't compare loose stuff on top of a hard base on a road to what goes on in soft stuff on a trail where the knobbies give traction. It would be more like some green stuff on a smooth rock which would also put you down trail riding.

While a lower CG could make it easier to save because less corrective force would be needed when putting a foot down or whatever, things definitely happen quicker when traction is lost with a lower CG. It's more than that though. On your mtn bike you are much closer to being part of the bike with feet on the pedals and the frame between your legs. You're much closer to just sitting on top of the scooter, and with your feet out front your legs can't offer much at all in the way of stability compared to being in line with your body and more vertical on your bike.

It sounds like a great adventure, so be more careful and be sure to tell us all about it. Take lots of picks. Try to completely avoid poor traction conditions, especially on a scooter, and when they can't be avoided no front brake at all. It might be worthwhile to practice on some wet grass, and see if foot placement and/or pressure through the feet and handlebars helps make you more joined to the scoot, and offer more control on the slick stuff.

John

Oh yeah, much different conditions to any trail conditions, even greasy slick mud with your knobbies coated with a half inch of it.

You just hit a patch slick as oil or ice, on street tires, and possibly needed no brakes at all to be on your way down. But still, a millisecond they locked will do er on that slick.

How surprisingly fast it happened shows how it was a true accident. I always know it's coming when I crash off road. You feel it that you're riding just above your ability for that particular moment, then whee!! It's rarely much of a surprise. But a true accident is always a complete bolt out of the blue to you.

Chalo is right, you do tend to protect your head in a crash. But it's not a guarantee. I wear a helmet, my choice. Crashing (like a simple laydown) in armor is definitely more comfy. If not, you were going to die in that crash helmet or no.

This scooter has a CVT transmission right? This also behaves differently than a motorcycle and could have had a slight impact on how quickly you lost control? Hope you get better soon.

Ykick said:

Even if you didn't apply it, a slightly dragging front brake could cause what you describe.

I hit a patch of spilled Diesel fuel many years ago on a moto. My front brake had been dragging just a bit and it put me on my ass in a flash.

'hope you're feeling better soon!

Click to expand...

I have seen a car get on a patch of transmission oil put there by a dropped and busted small jug of oil, and immediately go totally uncontrollable.

The photo of the fall victim sitting on the pebbles looks to me like the pebbles have the unique glisten, or, sheen, of oil coating.

I suspect an oil spill.


GONZ

Drunkskunk said:

The very low center of gravity on those scooters means that when they start to fall over, gravity has them on the ground faster than your reaction time. once they start to go, they are gone.

Click to expand...

My experience on two wheels on both small-wheeled scooters and big wheeled full size motorcycles makes me think that the big wheels are much more stable because they are much more powerful as gyroscopes. My full size motorcycle rides were definitely much more difficult to tip over. I never noticed that high or low center of gravity seemed to have much to do with it. My scooter rides were always a little spooky even under perfect conditions. My motorcycle rides were always more stable by a big factor.

A related factor is, an experienced motorcycle rider may develop a reflex for quickly putting a foot or feet on the ground to act somewhat like a training wheel to prop up the bike on its low side. The wide body and floorboard of a scooter may deter such action, and a chronic scooter rider might never even learn to save their ride with such foot action.

I have ridden many miles on two wheels on roads so slick from ice that I had great trouble walking on the stuff, I'm speaking from experience.


GONZ