Sexton's front wheel

Viewsonic
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Viewsonic
Edited Date/Time 2/25/2022 5:09pm
I couldn't be certain, but despite all the talk to the contrary, it appears Chases's front wheel folded and then caused his wreck Saturday. I have seen a lot of high sides in decades of watching pro racing, of all forms, and never saw a high side fold a rim like that. World Championship 500 road racers high sided reasonably often in the Roberts/Spencer era, with much more force, weight, and speed decades ago. GNC, Class C, etc. high side much heavier, faster bikes. On and on, Dakar bikes, Baja racers, I've never seen it. People mention Baggett had a crash like this, but I believe his rim may have folded first as well then. If the force of the high side bent the rim wouldn't other parts of the front of the bike bend as well, handlebars, etc.? Wouldn't his tire have been flat?
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Mr. Afterbar
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Mr. Afterbar 2/23/2022 4:39am
2/23/2022 4:39am
The wheel failed when he knifed the front end into the face of the jump. It's been covered multipld times in multiple threads where youcould have shared your thoughts.
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motonation24 2/23/2022 4:44am
2/23/2022 4:44am
Get this thread to the Dumbgeon ASAP!
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DownSouth
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DownSouth 2/23/2022 4:57am
2/23/2022 4:57am Edited Date/Time 2/23/2022 4:59am
Those spoked wheels on 500 gp road race bikes failed all the time. Cool


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Viewsonic
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Viewsonic 2/23/2022 5:13am
2/23/2022 5:13am
Road racers ran wire wheels up until the early seventies, plenty of photos of Ago, Roberts, Castro, etc. on wire wheels. Mag wheels were not invented before motorcycles, they were quite controversial when they first arrived in road racing to some. As a matter of fact, Russian motocross racers, Moiseev and the like, ran mag wheels on their factory KTM's for a while, they found wire wheels held up better. I prefaced my post with "despite all the talk to the contrary", that means I acknowledge different opinions. The video sure looks like the wheel caused the wreck though. Like I said, his tire still held air.
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Gary Duck
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Gary Duck 2/23/2022 6:21am
2/23/2022 6:21am
Viewsonic wrote:
Road racers ran wire wheels up until the early seventies, plenty of photos of Ago, Roberts, Castro, etc. on wire wheels. Mag wheels were not invented...
Road racers ran wire wheels up until the early seventies, plenty of photos of Ago, Roberts, Castro, etc. on wire wheels. Mag wheels were not invented before motorcycles, they were quite controversial when they first arrived in road racing to some. As a matter of fact, Russian motocross racers, Moiseev and the like, ran mag wheels on their factory KTM's for a while, they found wire wheels held up better. I prefaced my post with "despite all the talk to the contrary", that means I acknowledge different opinions. The video sure looks like the wheel caused the wreck though. Like I said, his tire still held air.
If you watch the crash again on YouTube and click the ".25 speed" playback you can literally see his wheel fold into a taco as it hits the up ramp sideways and eject him off the bike.
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mx317
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mx317 2/23/2022 6:29am
2/23/2022 6:29am
Viewsonic wrote:
Road racers ran wire wheels up until the early seventies, plenty of photos of Ago, Roberts, Castro, etc. on wire wheels. Mag wheels were not invented...
Road racers ran wire wheels up until the early seventies, plenty of photos of Ago, Roberts, Castro, etc. on wire wheels. Mag wheels were not invented before motorcycles, they were quite controversial when they first arrived in road racing to some. As a matter of fact, Russian motocross racers, Moiseev and the like, ran mag wheels on their factory KTM's for a while, they found wire wheels held up better. I prefaced my post with "despite all the talk to the contrary", that means I acknowledge different opinions. The video sure looks like the wheel caused the wreck though. Like I said, his tire still held air.
Why would his tire not hold air? It's not tubeless and would lose air if pulled away from the rim.
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aeffertz
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aeffertz 2/23/2022 6:57am
2/23/2022 6:57am
The crash caused the wheel to bend, not the other way around.
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McG194
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McG194 2/23/2022 8:29am
2/23/2022 8:29am
aeffertz wrote:
The crash caused the wheel to bend, not the other way around.
Technically incorrect.
He was pushing the front wheel which was turned at an almost 90-degree angle. Once that wheel impacted the jump face it stopped dead which caused the wreck which resulted in the taco'ed rim.

As far as a mag wheel, it would never work in moto. The wheel needs much more give than a one-piece wheel will allow. The old engineering adage holds true, if it can't shake it's going to break. Spokes are constantly under compression and extension forces.
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mxtech1
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mxtech1 2/23/2022 10:24am
2/23/2022 10:24am
The simple fact is that that these wheels are not designed to handle high thrust forces from the side. The hub is designed to absorb the forces through *mostly* vertical forces transmitted through the spokes. When the wheel is loaded through the side, those forces cannot translate through the spoke into the hub, rather they are absorbed by the rim until it bends.
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aeffertz
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aeffertz 2/23/2022 10:29am
2/23/2022 10:29am Edited Date/Time 2/23/2022 10:31am
aeffertz wrote:
The crash caused the wheel to bend, not the other way around.
McG194 wrote:
Technically incorrect. He was pushing the front wheel which was turned at an almost 90-degree angle. Once that wheel impacted the jump face it stopped dead...
Technically incorrect.
He was pushing the front wheel which was turned at an almost 90-degree angle. Once that wheel impacted the jump face it stopped dead which caused the wreck which resulted in the taco'ed rim.

As far as a mag wheel, it would never work in moto. The wheel needs much more give than a one-piece wheel will allow. The old engineering adage holds true, if it can't shake it's going to break. Spokes are constantly under compression and extension forces.
You just agreed with me while saying it’s incorrect… The crash started before the wheel bent. Saying he crashed because the wheel was bent isn’t correct. Like you just explained, he washed the front end into the face of a jump and high sided. The crash was happening either way, the wheel absorbing some of that force and bending is a result of the crash, not the cause.
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McG194
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McG194 2/23/2022 11:10am
2/23/2022 11:10am
aeffertz wrote:
The crash caused the wheel to bend, not the other way around.
McG194 wrote:
Technically incorrect. He was pushing the front wheel which was turned at an almost 90-degree angle. Once that wheel impacted the jump face it stopped dead...
Technically incorrect.
He was pushing the front wheel which was turned at an almost 90-degree angle. Once that wheel impacted the jump face it stopped dead which caused the wreck which resulted in the taco'ed rim.

As far as a mag wheel, it would never work in moto. The wheel needs much more give than a one-piece wheel will allow. The old engineering adage holds true, if it can't shake it's going to break. Spokes are constantly under compression and extension forces.
aeffertz wrote:
You just agreed with me while saying it’s incorrect… The crash started before the wheel bent. Saying he crashed because the wheel was bent isn’t correct...
You just agreed with me while saying it’s incorrect… The crash started before the wheel bent. Saying he crashed because the wheel was bent isn’t correct. Like you just explained, he washed the front end into the face of a jump and high sided. The crash was happening either way, the wheel absorbing some of that force and bending is a result of the crash, not the cause.
I admittedly was splitting hairs. Even if no jump was there to stop the wheel he was crashing.
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neysbo
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neysbo 2/23/2022 11:19am
2/23/2022 11:19am
End of the day the wheel failed and caused a DNF
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gt80rider
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gt80rider 2/23/2022 11:42am
2/23/2022 11:42am
I've never seen anything like that before.... ever... and.. if I went out to try and duplicate it, I don't think I could... I've had numerous crazy incidents over the past 40+ yrs that would have been even harder on a front wheel, yet I've never taco'ed a front like that....

What I'm saying here...and perhaps what OP is saying that - ya... either the wheel was compromised before that corner.... or something broke when it should not have...
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m121c 2/23/2022 11:44am
2/23/2022 11:44am

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2whlfun
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2whlfun 2/23/2022 11:56am
2/23/2022 11:56am
gt80rider wrote:
I've never seen anything like that before.... ever... and.. if I went out to try and duplicate it, I don't think I could... I've had numerous...
I've never seen anything like that before.... ever... and.. if I went out to try and duplicate it, I don't think I could... I've had numerous crazy incidents over the past 40+ yrs that would have been even harder on a front wheel, yet I've never taco'ed a front like that....

What I'm saying here...and perhaps what OP is saying that - ya... either the wheel was compromised before that corner.... or something broke when it should not have...
Super stiff forks seem to be a factor
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Viewsonic
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Viewsonic 2/23/2022 1:34pm
2/23/2022 1:34pm
My points are misunderstood. Particularly the air in the tire. To help explain, it wasn't Chase's rim contacting the dirt, it was the super small contact patch of the front tire. If you have a bike in the garage look at how many knobs are touching the ground, 6 maybe 8 in loose dirt? That that little contact patch can bend a rim without losing traction(sliding), continuing to roll, or ripping off the rim is hard to believe. A 21' tire can roll over a pretty big obstacle. Take the biggest vise grips you have and lock them on your front tire tread (not the rim), put the biggest pipe you have on the handle of the vise grips and pull as hard as you can - what would happen first - tearing the tire off the rim or bending the rim? Simply putting a bicycle rims axle in your hand and spinning it, or using a truing stand shows how much a spinning wheel wants to remain in motion. I believe Chase's rim failed and caused the high side. The mathematics of 450lbs of Chase and bike going 25mph-30mph at that angle and bending a rim in that circumstance are odd as well. Not impossible but not likely.
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Dirty Points 2/23/2022 2:15pm
2/23/2022 2:15pm Edited Date/Time 2/23/2022 3:19pm
Viewsonic wrote:
My points are misunderstood. Particularly the air in the tire. To help explain, it wasn't Chase's rim contacting the dirt, it was the super small contact...
My points are misunderstood. Particularly the air in the tire. To help explain, it wasn't Chase's rim contacting the dirt, it was the super small contact patch of the front tire. If you have a bike in the garage look at how many knobs are touching the ground, 6 maybe 8 in loose dirt? That that little contact patch can bend a rim without losing traction(sliding), continuing to roll, or ripping off the rim is hard to believe. A 21' tire can roll over a pretty big obstacle. Take the biggest vise grips you have and lock them on your front tire tread (not the rim), put the biggest pipe you have on the handle of the vise grips and pull as hard as you can - what would happen first - tearing the tire off the rim or bending the rim? Simply putting a bicycle rims axle in your hand and spinning it, or using a truing stand shows how much a spinning wheel wants to remain in motion. I believe Chase's rim failed and caused the high side. The mathematics of 450lbs of Chase and bike going 25mph-30mph at that angle and bending a rim in that circumstance are odd as well. Not impossible but not likely.
This structural failure is pretty complex. So many materials and forces at play. But one thing we do know, just in general: applying a static load like a pipe wrench to a structure is not a good model for the same structure's behavior under dynamic or impact loading.
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TriRacer27 2/23/2022 2:33pm
2/23/2022 2:33pm
Viewsonic wrote:
My points are misunderstood. Particularly the air in the tire. To help explain, it wasn't Chase's rim contacting the dirt, it was the super small contact...
My points are misunderstood. Particularly the air in the tire. To help explain, it wasn't Chase's rim contacting the dirt, it was the super small contact patch of the front tire. If you have a bike in the garage look at how many knobs are touching the ground, 6 maybe 8 in loose dirt? That that little contact patch can bend a rim without losing traction(sliding), continuing to roll, or ripping off the rim is hard to believe. A 21' tire can roll over a pretty big obstacle. Take the biggest vise grips you have and lock them on your front tire tread (not the rim), put the biggest pipe you have on the handle of the vise grips and pull as hard as you can - what would happen first - tearing the tire off the rim or bending the rim? Simply putting a bicycle rims axle in your hand and spinning it, or using a truing stand shows how much a spinning wheel wants to remain in motion. I believe Chase's rim failed and caused the high side. The mathematics of 450lbs of Chase and bike going 25mph-30mph at that angle and bending a rim in that circumstance are odd as well. Not impossible but not likely.
You're thinking of it wrong. It's not just the size of the contact patch, it's how much torque it can cause. Think of what would happen if you were sliding along a street and suddenly hit the curb. The size of the contact patch wouldn't change much, but the amount of force going through the wheels would change drastically. It's also not just the size of the load, but the shock (how quickly it ramps up).

Chase hit the jump at just the right angle where the forces that would cause the wheel to roll forward from his momentum and roll backwards equalized, so all that force transferred into spitting both him and the bike up.

There may have been some damage to the spokes before, but I find it very hard to believe the wheel was somehow bent before the impact with the jump face and not because of it.

The tire going flat or not has nothing to do with this. It's a tube. You can literally twist it in a knot and it'll still hold air.
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soggy
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soggy 2/23/2022 2:34pm
2/23/2022 2:34pm
gt80rider wrote:
I've never seen anything like that before.... ever... and.. if I went out to try and duplicate it, I don't think I could... I've had numerous...
I've never seen anything like that before.... ever... and.. if I went out to try and duplicate it, I don't think I could... I've had numerous crazy incidents over the past 40+ yrs that would have been even harder on a front wheel, yet I've never taco'ed a front like that....

What I'm saying here...and perhaps what OP is saying that - ya... either the wheel was compromised before that corner.... or something broke when it should not have...
Case closed guys. Gtrider has ridden since the dinosaur era and never bent a wheel like that so it’s not possible unless it was damaged before.
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flap
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flap 2/23/2022 3:07pm
2/23/2022 3:07pm
Viewsonic wrote:
My points are misunderstood. Particularly the air in the tire. To help explain, it wasn't Chase's rim contacting the dirt, it was the super small contact...
My points are misunderstood. Particularly the air in the tire. To help explain, it wasn't Chase's rim contacting the dirt, it was the super small contact patch of the front tire. If you have a bike in the garage look at how many knobs are touching the ground, 6 maybe 8 in loose dirt? That that little contact patch can bend a rim without losing traction(sliding), continuing to roll, or ripping off the rim is hard to believe. A 21' tire can roll over a pretty big obstacle. Take the biggest vise grips you have and lock them on your front tire tread (not the rim), put the biggest pipe you have on the handle of the vise grips and pull as hard as you can - what would happen first - tearing the tire off the rim or bending the rim? Simply putting a bicycle rims axle in your hand and spinning it, or using a truing stand shows how much a spinning wheel wants to remain in motion. I believe Chase's rim failed and caused the high side. The mathematics of 450lbs of Chase and bike going 25mph-30mph at that angle and bending a rim in that circumstance are odd as well. Not impossible but not likely.
Air pressure? What about a mousse insert? Not sure what HRC runs but seems like they might to avoid flats..
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Ryan625
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Ryan625 2/23/2022 4:49pm
2/23/2022 4:49pm
Why is this still a debate?
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Kawboy14!
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Kawboy14! 2/23/2022 5:01pm
2/23/2022 5:01pm
He hit a brick wall with the front wheel turned sideways ….at Ludicrous Speed!
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Yeti831
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Yeti831 2/24/2022 12:05am
2/24/2022 12:05am
neysbo wrote:
End of the day the wheel failed and caused a DNF
Ehh… let’s be honest, without a taco’d wheel he still wasn’t going back in. I’m glad he’s cleared to race this weekend, but he was a heavy medical no-no following that hit. It didn’t initially look like it, but he got knocked pretty damn hard.

It’s still crazy how sudden his wheel just cracked out of traction given how good he looked the rest of the corner.
wrc777
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wrc777 2/24/2022 5:08am
2/24/2022 5:08am
neysbo wrote:
End of the day the wheel failed and caused a DNF
Yeti831 wrote:
Ehh… let’s be honest, without a taco’d wheel he still wasn’t going back in. I’m glad he’s cleared to race this weekend, but he was a...
Ehh… let’s be honest, without a taco’d wheel he still wasn’t going back in. I’m glad he’s cleared to race this weekend, but he was a heavy medical no-no following that hit. It didn’t initially look like it, but he got knocked pretty damn hard.

It’s still crazy how sudden his wheel just cracked out of traction given how good he looked the rest of the corner.
If the wheel did have some damage prior to the crash it could be why there was a crash. A wheel that goes soft will flex and dig in and create more grip than an undamaged wheel. It is possible the wheel was damaged and caused the crash which finished off the wheel.
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Joey_Bridges
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Joey_Bridges 2/24/2022 5:13am
2/24/2022 5:13am
So is the wheel going to be cleared to race at Arlington ??

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LoudLove
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LoudLove 2/24/2022 5:28am
2/24/2022 5:28am Edited Date/Time 2/24/2022 5:29am
Joey_Bridges wrote:
So is the wheel going to be cleared to race at Arlington ??

Did it pass rotation protocols?

I’ll show myself out…
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mxtech1
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mxtech1 2/24/2022 7:48am
2/24/2022 7:48am
Joey_Bridges wrote:
So is the wheel going to be cleared to race at Arlington ??

LoudLove wrote:
Did it pass rotation protocols?

I’ll show myself out…
I heard the wheel had a Skype interview with a mechanic who deemed it okay to race next weekend.
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TriRacer27 2/24/2022 9:13am
2/24/2022 9:13am
Joey_Bridges wrote:
So is the wheel going to be cleared to race at Arlington ??

LoudLove wrote:
Did it pass rotation protocols?

I’ll show myself out…
mxtech1 wrote:
I heard the wheel had a Skype interview with a mechanic who deemed it okay to race next weekend.
Taco bout a cheesy joke man. Is this all just a wheelie big joke to you?
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KurtJ99
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KurtJ99 2/24/2022 9:20am
2/24/2022 9:20am
neysbo wrote:
End of the day the wheel failed and caused a DNF
Yeti831 wrote:
Ehh… let’s be honest, without a taco’d wheel he still wasn’t going back in. I’m glad he’s cleared to race this weekend, but he was a...
Ehh… let’s be honest, without a taco’d wheel he still wasn’t going back in. I’m glad he’s cleared to race this weekend, but he was a heavy medical no-no following that hit. It didn’t initially look like it, but he got knocked pretty damn hard.

It’s still crazy how sudden his wheel just cracked out of traction given how good he looked the rest of the corner.
I think without a taco'd front wheel he definitely was going to grab his bike and go back in. If it wasn't for the trackside guys holding him back we would have had a risky track re-entrance/finish.
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MyBobbym
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MyBobbym 2/24/2022 9:30am
2/24/2022 9:30am
Never would have happened if team Honda were running Metzler front tires.
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