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Emergency braking will wreck your tyres instantly?

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Emergency braking will wreck your tyres instantly?

Old 10-18-22, 11:41 AM
  #26  
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Originally Posted by cyccommute
That has nothing to do with maximum deceleration. You can lock your elbows without pushing back on the saddle and that will not increase deceleration. Moving the center of gravity will. It’s a fluke of our high center of gravity mode of travel. Tandems, for example, can’t be pitched over because the center of gravity is further back, making lifting the rear wheel high enough to go over the handlebars impossible.
Kind of hard to lock your elbows without moving back.
Don;t believe me?
Then pull yourself up over the bars and hog down on the brake.
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Old 10-18-22, 12:42 PM
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Originally Posted by kwb377
The theory behind ABS is vehicle control, not maximum braking. ABS allows one to maintain steering control, but it increases stopping distance. Maximum braking/minimum stopping distance is achieved via threshold braking (the point just before lock-up)...ABS takes the vehicle to the point of threshold braking, then releases the brakes momentarily, then reapplies, then releases, etc.
There are better and worse ABS systems. Subarus seen to have very, very good ones. I've at least twice known for sure I was getting creamed by those cars and they've stopped in time. And I am pretty darn certain those drivers were not doing sophisticated pedal work. My Prius is disappointing. I can out stop the ABS but the power assist is so strong, being light enough on the pedal is still hard for this guy who learned to drive in an ancient jeep and whose previous cars had no assist, then far less assist than the Prius. I'd love to have half the assist disappear. I'd be a better driver. And I'd use the ABS less.
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Old 10-18-22, 01:58 PM
  #28  
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Originally Posted by Bill Kapaun
You get maximum braking when you DON'T skid.
You get maximum braking on the front since most your weight is transferring in that direction.
Practice your panic stops so you can perform one without a skid.
True, one gets traction without skidding, but skidding happens once in a while.

The important thing is that the OP survived without crashing. It may well be worth a new tire, or even a tire boot.

It does depend on the brand. I like my Conti Gator Hardshells. I still don't skid much, but I'm pretty sure they'd take a skid and keep rolling.

I did try a practice hard stop with my Origin-8 Elimin8ors. I think those are out of production now. But, they had a softer green outer layer, and then they got down to a black inner layer. And, once I exposed that black layer, they wore for quite some time. It is like that layer wore like steel.
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Old 10-18-22, 02:18 PM
  #29  
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Originally Posted by Bill Kapaun
Kind of hard to lock your elbows without moving back.
Don;t believe me?
Then pull yourself up over the bars and hog down on the brake.
Not hard at all. Most newbies…and not a few experienced…riders need to be reminded not to ride with locked elbows. Even when pushing back, you don’t necessarily need to go to the point where your elbows are locked. As for braking when my elbows are flexed, I do it all the time. Generally, it’s better to brake (and ride) will out locking your elbows. It has no effect on overall deceleration of the bicycle during braking.
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Old 10-18-22, 02:20 PM
  #30  
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Originally Posted by jxpowers
Hi all,

Little backstory: had to brake super hard cause a car turned into the cycle lane unexpectedly, skidded for a few meters. Luckily I didn't come off and came to a safe stop.

Anyway this is how my tyres looked after, only had them 2 months, is this normal? For the tyre to shred right down to the next layer or tyre.
Just thought they might have a bit more longevity to them that's all. But if this is normal then fair, otherwise a little sad I have to buy replacements
It’s not all that unusual. Road tires are usually made for lightness rather than durability. It’s fairly easy to rub through one if you lay down a long patch of rubber…because there’s not much rubber there.
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Old 10-18-22, 02:50 PM
  #31  
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Originally Posted by FBinNY
IME no, but historically bike and brake geometry was such that the rear brake offered less leverage to the rider, so some proportioning was designed in. I've no idea whether this was intentional or serendipitous.
I owned an early-'70s Frejus for a while, and I was always puzzled by its having been designed such that it required a longer-reach brake in the back. I suppose it's possible that the bike designer was motivated by the desire to reduce the likelihood that the rear brake would lock in a panic stop. (Though I doubt that small differences in the distance from mounting bolt to pad can affect panic braking responses perceptibly, let alone significantly.)

My guess now, having learned over the years how cost-cutting and production streamlining tended to take priority in such factories, is that it was cheaper and faster to cut all their brake bridges to the same length and braze them in place wherever they happened to fit for the various frame sizes.

Another speculation presented in an earlier post was that frame builders designed their bikes to use full-length housing to lessen the firmness of the the rear brake response, again with the aim of enabling better-controlled panic stops. Never came across that claim before.

However, what I was told when I was working in bike shops and racing back then was that frame builders used as few braze-on fittings as possible on their high-end frames to avoid overheating such thin tubing, which could lead to cracking of the tubes. The top tube used the thinnest tubing, so cable clips would be used there.

Also, at least some of the lower-end bikes from those manufacturers had braze-ons, including top tube braze-ons (for use with segmented brake housing), where the upper-end bikes didn't, at least during the mid-to-late '70s.

Anyway, other than that one Frejus, I've always had front and rear brakes that matched in every respect. And, despite having owned a good number of pro-level bikes, some with continuous rear brake housing, some with interrupted housing, I've never noticed any difference in braking efficacy that I can attribute to the type of rear housing, number of pivots, etc. I could certainly effortlessly skid the rear wheel with any rim brake bike I've ever owned or ridden.

Last edited by Trakhak; 10-18-22 at 02:54 PM.
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Old 10-18-22, 02:52 PM
  #32  
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Originally Posted by cyccommute
Not hard at all. Most newbies…and not a few experienced…riders need to be reminded not to ride with locked elbows. Even when pushing back, you don’t necessarily need to go to the point where your elbows are locked. As for braking when my elbows are flexed, I do it all the time. Generally, it’s better to brake (and ride) will out locking your elbows. It has no effect on overall deceleration of the bicycle during braking.
Riding with locked elbows does equate to braking with locked elbows!
That just shows how you are just looking to argue.

I brake all the time with flexed elbows.
There's a hell of a lot of difference between NORMAL and PANIC braking.
That just shows how you are just looking to argue.

I wasn't replying to this topic for you. Give me a break
I was replying to an obviously inexperienced ORIGINAL POSTER in a manner that I felt was easier to understand to THEM!
Yet you need to nit pick because something doesn't reach your state of perfection.
Back to the ignore list. Forever this time.
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Old 10-18-22, 02:59 PM
  #33  
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No matter how you slice it. A large skid wear area is proof of poor braking skills.

When braking, whether normal or an emergency stop, weight shifts forward unloading the rear wheel. In maximum effort braking the rear axle weight approaches zero, so hard wear won't happen even if the rear wheel is locked.

The above applies whenever the front brake is used at least somewhat effectively. The ONLY way to take that much tread off a tire is to ignore the front brake and lock the rear wheel while keeping yourself firmly on the saddle.

FWIW for those curious about whether a weaker rear brake would help, the answer is no. During braking, as the rear axle load approaches zero, so does the lever force needed to lock the rear wheel. That means that any meaningful effort to prevent rear wheel skids would render the brake totally ineffective otherwise.

The key to safe stopping is a well conditioned biofeedback loop. It's something developed with good training and experience.

Good engineering demands that brakes are capable of delivering more wheel stopping power than needed to stop a bike within the minimum theoretical distance.

Last edited by FBinNY; 10-18-22 at 03:16 PM.
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Old 10-18-22, 03:53 PM
  #34  
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Next time use your front brake. It doesn't skid.
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Old 10-18-22, 03:56 PM
  #35  
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Originally Posted by Yan
Next time use your front brake. It doesn't skid.
Apparently you are unaware of sand & ice?
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Old 10-18-22, 04:15 PM
  #36  
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Originally Posted by Bill Kapaun
Apparently you are unaware of sand & ice?
You have a much higher probability of dying after being hit by by a car compared to slipping on sand & ice. You would prefer the car?

What percent of your amongst-traffic riding involves sand & ice? Do you live in an area where most automobile roads are dirt? Are you a winter commuter in a snowy region?

OP is riding a skinny tire road bike. Do you think people frequently ride this type of bike in sand and snow?

Last edited by Yan; 10-18-22 at 04:23 PM.
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Old 10-18-22, 04:36 PM
  #37  
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Originally Posted by Bill Kapaun
Riding with locked elbows does equate to braking with locked elbows!
That just shows how you are just looking to argue.
And braking with locked elbows does nothing for increasing deceleration. It’s not about how hard you squeeze the levers but have much deceleration you can apply before going over the bars. Moving the center of gravity rearward and downward (perhaps with locked elbow but perhaps not) increases deceleration because it takes more force to lift the rear wheel.

I brake all the time with flexed elbows.
There's a hell of a lot of difference between NORMAL and PANIC braking.
I too brake all the time with flexed elbows. And I would agree that there is a lot of difference between “NORMAL and PANIC” braking. But the difference isn’t because of locked elbows or because of using different muscles.

That just shows how you are just looking to argue.
Only when people give bad advice.

I wasn't replying to this topic for you. Give me a break
Or is that a “brake”?

I was replying to an obviously inexperienced ORIGINAL POSTER in a manner that I felt was easier to understand to THEM!
Well considering that you quoted me, I kinda felt you were responding to me.

Yet you need to nit pick because something doesn't reach your state of perfection.
Back to the ignore list. Forever this time.
Is there anyone who is not on your ignore list?
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Old 10-18-22, 04:39 PM
  #38  
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Originally Posted by Yan
You have a much higher probability of dying after being hit by by a car compared to slipping on sand & ice. You would prefer the car?

What percent of your amongst-traffic riding involves sand & ice? Do you live in an area where most automobile roads are dirt? Are you a winter commuter in a snowy region?

OP is riding a skinny tire road bike. Do you think people frequently ride this type of bike in sand and snow?
How old are you, 10?
Thanks to a city that does an extremely poor job of keeping bike lanes swept, there is always some degree of fine silt/sand build up. Sometimes to point of being skittish in straight sections unless you have a treaded tire. My tires are smooth.
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Old 10-18-22, 05:03 PM
  #39  
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Originally Posted by Bill Kapaun
How old are you, 10?
Thanks to a city that does an extremely poor job of keeping bike lanes swept, there is always some degree of fine silt/sand build up. Sometimes to point of being skittish in straight sections unless you have a treaded tire. My tires are smooth.
Treaded tire? Treads need to interlock with a deformable terrain to make a difference. If it's a hard surface with a scattering of sand, treads don't do anything.

You're talking about road dirt building up to the point where you need mountain bike tires to ride on asphalt? How deep is this road dirt on Oregon roads exactly? Deep enough for treads to dig into? Holy smokes... Is it from the volcanos you guys have over there?

And you have personally fallen after locking your front wheel braking in this road dirt?

Last edited by Yan; 10-18-22 at 05:08 PM.
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Old 10-18-22, 05:49 PM
  #40  
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Originally Posted by Yan
Treaded tire? Treads need to interlock with a deformable terrain to make a difference. If it's a hard surface with a scattering of sand, treads don't do anything.

You're talking about road dirt building up to the point where you need mountain bike tires to ride on asphalt? How deep is this road dirt on Oregon roads exactly? Deep enough for treads to dig into? Holy smokes... Is it from the volcanos you guys have over there?

And you have personally fallen after locking your front wheel braking in this road dirt?
How old are you? 9?
I;m intelligent/mature enough to not over ride the conditions available.
I've yet to see an intelligent post from you and often offer stupid or dangerous advice because of your lack of knowledge.
You're a little yippy dog barking at the heels of a real dog.
Ignore list for children like you. I hope the more tolerant people will keep an eye on you.
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Old 10-18-22, 05:56 PM
  #41  
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Originally Posted by cyccommute
Is there anyone who is not on your ignore list?
And the truly funny thing is that he thinks he’s punishing us when he makes those silly threats!
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Old 10-18-22, 06:03 PM
  #42  
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Originally Posted by Bill Kapaun
How old are you? 9?
I;m intelligent/mature enough to not over ride the conditions available.
I've yet to see an intelligent post from you and often offer stupid or dangerous advice because of your lack of knowledge.
You're a little yippy dog barking at the heels of a real dog.
Ignore list for children like you. I hope the more tolerant people will keep an eye on you.
I asked you some very simple, very direct questions. And you were able to answer none of them. Stumped?

My questions were all related to the topic. But you? Do you have anything bicycle related to say? Or are you just going to complain and evade like a coward?

If you are clueless just admit it. Stop gyrating in the wind

I ask again, have you ever personally fallen after locking up your front wheel in this Oregon road sand of yours? Yes or no, simple question.

Last edited by Yan; 10-18-22 at 06:08 PM.
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Old 10-19-22, 09:27 PM
  #43  
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We used to skid our coaster brake bikes when we were kids too. We had contests to see who could lay the longest patch. And our tires had flat spots. And my buddy Steve's rear tire exploded as he was laying one down. That was OK, his parents used to buy him just about anything he wanted.
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Old 10-21-22, 09:27 AM
  #44  
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[QUOTE=jxpowers;22682185]Anyway this is how my tyres looked after, only had them 2 months, is this normal? For the tyre to shred right down to the next layer or tyre.[QUOTE]
I'd be checking for irregularity or contamination of the rim or rotor (depending on brake type) that could cause patchy tyre wear under braking. When traction isn't a problem, using just the front brake will stop you as quickly as using both, and may leave you in better control because the back end won't be going sideways.
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Old 10-23-22, 11:18 PM
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Originally Posted by Yan
Next time use your front brake. It doesn't skid.
I did, I hit both brakes. Still skidded.

I don't think many people on here realise that I was on a bike lane which meant lots of loose gravel and debris from the road will gather.

I know lots of people mentioned poor braking, but no one seemed to realise not everyone has a spare pair of tyres to "practice" emergency brakingbrakin

Also the road conditions meant that skidding was inevitable.
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Old 10-24-22, 12:44 AM
  #46  
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Originally Posted by jxpowers
I did, I hit both brakes. Still skidded.

I don't think many people on here realise that I was on a bike lane which meant lots of loose gravel and debris from the road will gather.

I know lots of people mentioned poor braking, but no one seemed to realise not everyone has a spare pair of tyres to "practice" emergency brakingbrakin

Also the road conditions meant that skidding was inevitable.
You misunderstood me. I said use the front brake only, don't touch the rear brake. The rear is the one that skids. If you don't touch the rear brake, you won't skid and you won't trash your tires.

I assume since you're riding on thin road bike tires, you're riding on a paved surface? Forget how dirty the asphalt is. Unless you're riding offroad on actual soft terrain, your front wheel will never skid no matter how hard you apply the front brake. You'll flip over the bars before the front tire slides out.

Experienced cyclist riding on asphalt pretty much never use their rear brakes. I urban commute and touch my rear brake less than five times a year. The rear brake doesn't slow you down. When you apply it, your rear tire starts sliding. At that point it is barely reducing your speed. Total waste of time. You're going to get hit by a car. And as you learned it also trashes your tire.

​​​Watch out for wet stone pavers and other kinds of slippery surfaces in the rain. There are occasionally some hard surfaces that could cause your front tire to slide out. Here you would want to use the rear brake. Wet asphalt is fine though.

Last edited by Yan; 10-24-22 at 12:58 AM.
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Old 10-24-22, 01:27 AM
  #47  
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Originally Posted by jxpowers
I did, I hit both brakes. Still skidded

I know lots of people mentioned poor braking, but no one seemed to realise not everyone has a spare pair of tyres to "practice" emergency brakingbrakin

Also the road conditions meant that skidding was inevitable.
Sliding is rarely inevitable. Effective controlled braking is a learned skill honed with experience. Just like like first learning to walk, dance, play piano, or bike ride, you learn by repetition and bio-feedback until the motor control system imprints the patterns that allow you to do these things smoothly.

Use both brakes, and focus on feeling when tires are on the verge of slipping. Over time you'll automatically modulate brake force to stop reliably in all conditions.
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Old 10-24-22, 01:56 AM
  #48  
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Originally Posted by jxpowers
......Also the road conditions meant that skidding was inevitable.
You need to reread post #7 until it sinks in.
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Old 10-24-22, 04:52 AM
  #49  
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Originally Posted by jxpowers
Also the road conditions meant that skidding was inevitable.
I’ve ridden a lot of miles in a few states and two countries. I’ve never encountered any roads where skidding was “inevitable.” Just lucky, I guess.

My thought is that if skidding was inevitable, your speed was too high.
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Old 10-24-22, 08:01 AM
  #50  
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Originally Posted by jxpowers
I did, I hit both brakes. Still skidded.

I don't think many people on here realise that I was on a bike lane which meant lots of loose gravel and debris from the road will gather.

I know lots of people mentioned poor braking, but no one seemed to realise not everyone has a spare pair of tyres to "practice" emergency brakingbrakin

Also the road conditions meant that skidding was inevitable.
I agree with you that there are situations where it is difficult to avoid sliding the rear tire. On clear, flat, dry pavement, control of the rear tire under braking is much easier. Add in water, sand, leaves, ice, etc. and that changes the situation significantly. Braking become far less predictable. You can do everything right and still end up sliding the rear tire.

Yes, you can avoid skidding if you don’t use the rear brake [Edit: Oops. Meant rear but said front] but you are also throwing away some of your decelerating ability and, more importantly, an important indicator by doing so. When you initiate braking, while both wheels are in contact with the ground, about 20% of your deceleration comes from the rear wheel. The amount of deceleration decrease rapidly as your weight shifts forward to the point where the rear wheel lifts and the front wheel is providing all of the deceleration. While this is where you approach maximum braking, you are also depending on the front wheel to provide both braking and control. The front wheel does a great job of steering the bike but it does a lousy job on its own…because it can steer. Keeping the rear wheel on the ground and rolling will keep the bike more stable.

To keep the rear wheel on the ground, get off the front brake by releasing it momentarily. In practice, I usually release both and then get back on them. You are in a situation where you really don’t want to think about too much and releasing both brakes takes less brain power. By doing this, you are decreasing your deceleration (slightly) but it allows the center of gravity of the bike to settle back down slightly. Moving that center of gravity takes time and is a curve. By releasing the brakes, you have flatten the curve just a little but you now have a bicycle instead of a unicycle…with a pivot in the middle of it.

There’s another aspect of braking that many people don’t practice nor understand. Pushing back and dropping down moves the center of gravity. A lower center of gravity increase the amount of deceleration you can achieve before you lift the rear wheel. You don’t have move all that much…a few inches both rearward and down…just about doubles the amount of deceleration you can achieve before wheel lift.

Under braking, the bike is a lever that is trying to push you up and over the bars. By moving back and down, you’ve increased the lever length which requires more force to lift the load. The result is you can slow faster without skidding.

As to your practice tires, frankly, your tire is toast. You do have a tire to practice emergency stopping on. Mount it up and go find a parking lot. Measure out a distance (or just eyeball it) and try braking while in the “normal” seated position and while pushing back and down on the bike. Practice it a lot until it becomes second nature. You can also practice this on gravel and wet grass. If you can learn to stop on those you’ll be golden.

Alternatively, get a mountain bike and have fun riding off-road. A hour of off-road riding will teach you more about braking than years of road riding.
__________________
Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!




Last edited by cyccommute; 10-26-22 at 08:42 AM. Reason: changed front brake to rear brake.
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