Lowside on a right turn

[TheRiddler]

I'm feeling pretty stupid about this since it was completely avoidable and completely my fault.

Where it happened:

I was riding my Vstrom westbound on Highway 12, about to make a right northbound onto Pennsylvania Avenue. I was doing about 50mph on 12, approaching the intersection that was backed up. I moved right, into the turning lane, and began slowing. I moved to the outside of the turning lane, while continuing to slow. I decided I could take the turn a little faster than I usually do, since I always have plenty of safety margin.

I slowed to about 20 mph and got off the brakes. I began to roll back on the throttle, and initiated my turn in. I leaned my body into the turn, but didn't adjust my position otherwise since I didn't feel it was needed. I was looking through, to the exit of the turn. I got about halfway through the turn, probably to the apex, when I suddenly felt the front end lose traction and the bars turned the wrong way. I immediately knew I was about to hit the pavement, which is exactly what happened. I was probably just under 25mph at this point.

Bike slid about 20 feet from the turn lane into the middle of the next lane. I slid maybe 5 feet. A couple people stopped at the light got out and helped me upright the bike, and I moved it to the shoulder. No functional damage, only cosmetic. Not a scratch on me.

What I did wrong:

1. Too fast. That mindset of "I can go a little faster" was the wrong one. The speed I normally take that turn at is perfectly safe, and I should have stuck with that. Although I'm still surprised I lost the front end at that speed on a turn that wide. There was no warning, and I wasn't leaned over far at all, maybe 30 degrees.

2. Along with too fast, overconfidence. Sure, I can often go faster, but that doesn't mean I should. I didn't adjust my body positioning since I didn't feel like I was going quick enough to merit it.

3. Treat an adventure bike like something it's not. I'm used to sportbikes and the Vstrom just doesn't corner the same, even though it feels effortless to ride. It's rocking 80/20 tires right now and it's obvious while riding that they don't offer the same traction as 100% street tires. I looked at the front tire afterwards, and it looks like it lost traction in a gap between the knobs.

What I did right:

1. Gear. Full face helmet, full gauntlet gloves, back protector, solid textile jacket, kevlar riding jeans, full length riding boots. I walked away literally without a scratch. One of the double-stitching seams on my jacket ripped and that was it.

Lesson: Slow down.

 

[Mortifer]

Was there anything on the pavement? gravel from cars cutting the corner?

 

[Ahab]

So you were on the throttle while you initiated the turn and added lean?
I have seen someone in front of me lose the front and go down. Wasn't even fast and totally surprised me. Among other possible reasons like some dirt, uneven surface etc (all not conclusive), the only technical mistake we figured caused the spill was "adding throttle and lean at the same time".
Curious what others have to say

 

[mbharat]

I am sorry to hear about your lowside, glad you are ok and the bike only suffered cosmetic damage. Excellent analysis.

... kevlar riding jeans...

So, the kevlar riding jeans DO work! I was always iffy about getting one but will definitely get one. More convenient sometimes on short jaunts.

Take care and hope to see you on the Vstrom soon.

 

[TheRiddler]

I checked the pavement afterwards. It looked clean. Some tiny pieces of gravel but nothing I'd consider a contributing factor.

So you were on the throttle while you initiated the turn and added lean?

Yep. Turn in and throttle were about simultaneous. Stayed on the throttle until the front end lost traction and I realized I was going down, but it was a very gradual roll on.

 

[rodr]

Odd. I've scraped pegs on my Wee many times without losing traction. A turn like that looks do-able at 30-35 mph. Surely something was going on with the road surface... what kind of tires?

EDIT: If you were pretty heavy on the throttle that could lighten the front end enough to be the main cause.

 

[Guoseph]

How close were you to the edge at apex? Any chance you clipped the off pavement gravel？ What kind of 80/20 tires? Most of those actually have pretty good street traction.

Next time ride it dirt bike style and catch front end tucks w your leg sticking out

 

[TheRiddler]

I figured I'd scrape pegs well before losing traction, but that didn't happen. The front is some sort of Shinko Trail tires. I definitely wasn't heavy enough on the throttle to get the front too light.

I was probably a good 3 feet from the roadway edge, so any gravel on the side would've been far enough away not to be a hazard.

 

[DataDan]

I agree with your analysis but would second what Ahab said, that you lost the front because you were on the gas before you got the bike turned.

With a narrow approach like that you really can't get the bike to the lean angle you need for the curve until the green. Then, when you're on a path that will take you to a good exit point, begin roll-on.

 

[Cornfish]

Sorry to hear about your low side. What if you delayed your turn entry point until you were closer to the outside of the turn lane? A few extra feet going straight might have allowed for more braking and then you could have made your move to turn and rolled on maintaining traction. Glad that you and the bike are ok!

 

[stangmx13]

I figured I'd scrape pegs well before losing traction, but that didn't happen. The front is some sort of Shinko Trail tires. I definitely wasn't heavy enough on the throttle to get the front too light.

...except u unexpectedly lost the front at a not-extreme lean angle. so your throttle input def contributed. had u been at maintenance throttle and were not accelerating, the front tire would have been weighted more and u would likely have had more grip to use for turning.

i bet u could have trail-braked to the X in your diagram and taken the corner faster with less risk.

 

[tzrider]

I'm undecided on the "throttle while turning" detail. You're normally not at risk of losing the front from this, but rather the rear.

OP, how far had you ridden up to this point? Was it a short ride? Had you gone around many right turns yet? If not, the front tire may not have been warm enough to support the lean angle you had.

Note that there is a difference between "blaming cold tires" and being aware of how ready the tires (or the surface) are for what you are about to do.

 

[stangmx13]

I'm undecided on the "throttle while turning" detail. You're normally not at risk of losing the front from this, but rather the rear.

IMO there def can be some contributing factors that would make the front let go before the rear in this situation. soft rear suspension w/ little swingarm angle will really let a bike squat and unload the front. also, the rider attempting to maintain their turning radius while throttling will require a constant steering input which would need more grip that the tire doesnt have. im sure theres more but those 2 stand out to me.

 

[TheRiddler]

...except u unexpectedly lost the front at a not-extreme lean angle. so your throttle input def contributed. had u been at maintenance throttle and were not accelerating, the front tire would have been weighted more and u would likely have had more grip to use for turning.

i bet u could have trail-braked to the X in your diagram and taken the corner faster with less risk.

That seems counter-intuitive, although I understand the logic. I've always presumed the safest way through any corner was to roll on the throttle exactly because it's getting weight off the front. I've never had a track trash, and this was the first time I've had a front tire let go on me (outside of obvious low-traction surfaces, like tar snakes). I've applied significantly more throttle through more challenging turns that didn't result in a crash. From corner entry to collision, there was probably less than a 5mph difference.

OP, how far had you ridden up to this point? Was it a short ride? Had you gone around many right turns yet? If not, the front tire may not have been warm enough to support the lean angle you had.

About 8 minutes, 4 stop signs and a red light, speeds from 25-60 mph. No turns yet. Basically straight from a residential zone to the highway.

It'd be surprising if a cold tire was the main contributing factor, given an ambient temp of about 80, and that my tires are far from high performance. I always suspected they'd require minimum warm-up to get to operating temp, but expected that at optimum temperatures they still wouldn't do anything impressive.

 

[afm199]

That seems counter-intuitive, although I understand the logic. I've always presumed the safest way through any corner was to roll on the throttle exactly because it's getting weight off the front. I've never had a track trash, and this was the first time I've had a front tire let go on me (outside of obvious low-traction surfaces, like tar snakes). I've applied significantly more throttle through more challenging turns that didn't result in a crash. From corner entry to collision, there was probably less than a 5mph difference.

The front has far more traction with a very small amount of brake squishing the tire than it does with throttle. I agree with Robert, brake much further in and try to avoid adding lean angle with the throttle on.

 

[Gary856]

In the spirt of crash analysis, I'm unsatisfied with OP's "what I did wrong/right" as they are all generic answers, but don't explain this specific crash - why the lost of front traction occurred at such a low speed wide turn, light throttle with shallow lean angle; and why it wasn't recoverable.

I got about halfway through the turn, probably to the apex, when I suddenly felt the front end lose traction and the bars turned the wrong way. I immediately knew I was about to hit the pavement, which is exactly what happened. I was probably just under 25mph at this point.

1. Have you experienced lost and re-gain front traction without crashing before? On dirt, pavement, or both?

2. I know it felt like the blink of an eye, but what were you doing (throttle, bar input, body) from the time you felt the front end lost traction to the time you hit the ground?

3. If yes for 1, how was 2 different this time?

 

[TheRiddler]

1. Have you experienced lost and re-gain front traction without crashing before? On dirt, pavement, or both?

2. I know it felt like a blink of the eye, but what were you doing (throttle, bar input, body) from the time you felt the front end lost traction to the time you hit the ground?

3. If yes for 1, how was 2 different this time?

1. Multiple times, only street. Never ridden dirt.

2. Let off throttle, had the realization that I lost traction, tried to steer the bars into it but had zero resistance, bailed off.

3. Lean angle, bike type, tire type, mentality, and length of ride. I've lost the front on tar snakes or in the rain, but usually when mostly straight up. Front has always regained traction without me doing anything. It's also typically been in adverse conditions where I was partially expecting limited traction, or if I was riding more aggressively and was more prepared to provide additional control inputs. This was also a 10 minute run to the store, instead of a ride to go ride.

 

[Gary856]

I have no way of knowing how exactly it happened, so all I can do is to bounce off some ideas for your consideration.

2. Let off throttle, had the realization that I lost traction, tried to steer the bars into it but had zero resistance, bailed off.

From your earlier description (shallow lean, gentle roll on) it didn't seem like the front was unloaded from excessive acceleration. You said you lean in your body, but was your body forward, neutral, or slightly backward from acceleration? Which way did you feel the bar went initially? By "tried to steer the bars into it - which side were you pushing forward? What did "let off throttle" do?

Assume your body position was forward or neutral, I tend to want to:
- maintain or slightly add throttle in a front slide,
- lean in my body slightly more, and
- either do nothing with the bar, or push left very slightly (in a right turn) to straighten out just a tiny bit then push right very slightly to resume course.

The idea is to allow the front to slide enough to get out of the low friction zone and auto-recover gently. I'm not even sure if I'm describing my reaction to slide recovery correctly, but hope it's enough to help you think thru it.

3. Lean angle, bike type, tire type, mentality, and length of ride. I've lost the front on tar snakes or in the rain, but usually when mostly straight up. Front has always regained traction without me doing anything. It's also typically been in adverse conditions where I was partially expecting limited traction, or if I was riding more aggressively and was more prepared to provide additional control inputs. This was also a 10 minute run to the store, instead of a ride to go ride.

Why would you lose the front when mostly straight up, even if there were tar snakes and/or rain? how do you define "lose the front" - a squirmy feeling or a slide of several inches?

I doubt if the bike or tire were the problem. If the hardware were the real blame for crashing in such a low threshold corner, don't you think they're too dangerous for everywhere?

Again, I feel none of the "differences" you listed, include mental readiness, adequately explained this particular crash as you described. To a large degree we rely on muscle memory for slide recovery, so not being ready for the slide didn't seem to affect the instinctive recovery actions in a number of unexpected slides I experienced. In fact, it's almost as if the less I think about it, the better my body reacts without me actively interfering with it.

Like it's often asked in crash analysis - do you think everyone (ok, the majority) would've crashed like you did under the same situation? I think it's worthwhile to put more focus on the "riding technique" aspect of this crash.

 

[stangmx13]

That seems counter-intuitive, although I understand the logic. I've always presumed the safest way through any corner was to roll on the throttle exactly because it's getting weight off the front. I've never had a track trash, and this was the first time I've had a front tire let go on me (outside of obvious low-traction surfaces, like tar snakes). I've applied significantly more throttle through more challenging turns that didn't result in a crash. From corner entry to collision, there was probably less than a 5mph difference.

there are likely some riding situations where that is the safest way to get through a corner. but with modern tires, even not sport tires on your Vstrom, i doubt it applies now as much as it did 30yrs ago.

unweighting the front tire decreases normal force which decreases friction which decreases grip. using the throttle to unweight the front tire does not decreases any cornering forces that are holding the tire in the turn. the rider must start to exit the corner for cornering forces to decrease. so, if the rider attempts to hold the same turn while throttling, they will get closer to the limit of grip, closer to crashing. i have no idea why this used to be an acceptable way to ride or even race. perhaps front tires were so shitty that trail braking didnt actually increase grip, so a rider needed to stop the bike to accomplish any turning. but that really isnt the case anymore. like afm199 said, a little bit of braking force squishing the tire into the asphalt dramatically increases grip, which really opens up a lot for getting through a corner safely.

 

[afm199]

there are likely some riding situations where that is the safest way to get through a corner. but with modern tires, even not sport tires on your Vstrom, i doubt it applies now as much as it did 30yrs ago.

unweighting the front tire decreases normal force which decreases friction which decreases grip. using the throttle to unweight the front tire does not decreases any cornering forces that are holding the tire in the turn. the rider must start to exit the corner for cornering forces to decrease. so, if the rider attempts to hold the same turn while throttling, they will get closer to the limit of grip, closer to crashing. i have no idea why this used to be an acceptable way to ride or even race. perhaps front tires were so shitty that trail braking didnt actually increase grip, so a rider needed to stop the bike to accomplish any turning. but that really isnt the case anymore. like afm199 said, a little bit of braking force squishing the tire into the asphalt dramatically increases grip, which really opens up a lot for getting through a corner safely.

I rode two up withe Ken Hill last week. I was scared to death. I KNEW there was no way the front tire could endure the amount of braking and force on it, right up to the apex of the corner. At the end I was just enjoying the hell out of the ride.

That was with street tires, btw, Pirelli Corsa. :laughing