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Old 10-27-2010, 11:46 AM   #31
Gary J
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Originally Posted by AOW View Post
Wouldn't increasing the tire pressure decrease the amount of contact patch? (image attached)
Arent' the "over" and "under" inflation example illustrations reversed form the headings in that illustration??

If I'm remembering correctly, exessive middle contact/wear is "over" inflation, and wearing on the opposing edges is "under" inflation. Am I missing something or are those illustrations reversed in that drawing??
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Old 10-27-2010, 02:24 PM   #32
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Originally Posted by Gary J View Post
Arent' the "over" and "under" inflation example illustrations reversed form the headings in that illustration??

If I'm remembering correctly, exessive middle contact/wear is "over" inflation, and wearing on the opposing edges is "under" inflation. Am I missing something or are those illustrations reversed in that drawing??

You are spot on, Gary. The outer two tread examples should be swapped.
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Old 10-27-2010, 02:32 PM   #33
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I think it shows that white area as being the wear. Seems right.
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Old 10-27-2010, 03:03 PM   #34
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I think it shows that white area as being the wear. Seems right.
I thought about that, but if that were their intent in the illustration, with the white representing the "wear area" where rubber does meet the road, shouldn't the "correct" tire pressure example in the middle be shown as basically "all white" .... rather than nearly all blackish, as it is?
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Old 10-27-2010, 07:32 PM   #35
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I have a follow up question, about this.

Quote:
o If bike starts to lose traction, in pushing the front tire, immediately apply additional throttle (light roll-on) to potentially recover by moving the greater load/force bearing to the rear tire
So my understanding is that if front starts to slide lightly rolling on the throttle might save it. I understand that it will unload the front, but how will it prevent the slide out? Does the bike straightens out? Seems like taking load from the front will make it more difficult to find traction again.

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Old 10-28-2010, 10:38 AM   #36
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So my understanding is that if front starts to slide lightly rolling on the throttle might save it. I understand that it will unload the front, but how will it prevent the slide out? Does the bike straightens out? Seems like taking load from the front will make it more difficult to find traction again.
Let me see if I can help clarify on this Alex. If the resultant direction of force (for weight on the front tire) were totally straight up-n-down, with the tire pressing directly into the pavement, at 90 degrees to that surface, then more would always be better; even if riding in the rain. Because of this aspect in some ways a heavier bike can actually provide better traction in the wet, than a light one, in some circumstances.

Unfortunately as soon as the bike begins to take a turn, and the direction of travel of the bike is being asked to change, cornering loads begin directing force less downward, and more outward. The result being the more load/force pushing in this off-angle direction, the higher the probability of exceeding the available traction level, and the tire beginning to slide.

As an extreme example of how throttle can be used to aid in the reduction of front end slides in these slippery rain conditions, think of what would happen if a stunter were taking a turn while doing a complete wheelie (front tire not even touching the ground). Obviously problems with front tire sliding out on the wet pavement, while taking the corner in this manner, would not be a factor.

Well looking at the situation from a more realistic perspective where the front tire is on the ground, the same “less is better” applies, when it comes to the amount of outward directed force the front tire is producing.

For a worst-case example, if you enter a wet turn with the throttle totally chopped (off), a large amount of the combined weight of the bike/rider will be directed forward, and the outward component of that force will surely cause the front tire to exceed available traction, slide outward, and the bike to crash.

By having the optimum amount of throttle applied when first entering, and while navigating a wet corner, a greatly reduced amount of that combined bike/rider weight will be on the front tire, with the rear doing the lion’s share. The end result being the front tire not exerting outward force at a level that exceeds the current traction limits, and the tire not sliding out.

If the magic number for when the front tire will exceed current traction limits and begin to slide is say 31, if a rider detects the initial onset of the slip VERY early, and give the bike a bit more throttle to take a little more load off the front end of the bike to a point where that demanded force drops to say 28 (or below), the tire may regain grip in time to prevent the crash.

No guarantees once a front tire starts to slide in the wet, but it’s the best chance of a save. Of course the best action being a defensive one, in having good wet weather cornering throttle control in the first place, to never allow the traction limits of the front tire to be exceeded.

Hope that helps clarify things Alex.
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Old 10-28-2010, 10:54 AM   #37
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I thought about that, but if that were their intent in the illustration, with the white representing the "wear area" where rubber does meet the road, shouldn't the "correct" tire pressure example in the middle be shown as basically "all white" .... rather than nearly all blackish, as it is?
It is rather confusing, and not the way I would have done it!
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Old 10-30-2010, 03:23 PM   #38
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As a result of closely analyzing all of the most subtle nuances of things I was doing in controlling the bike during a couple hundred miles of "True Grit" rain riding today, I've added a few updates to the tips and techniques content within the original posting in this tread.

Please revisit if you have an interest in doing so. Thanks.
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Old 10-30-2010, 10:39 PM   #39
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Kewl, thanks. I saw you ride through STP parking lot today. How do you keep that bike so clean?

Actually I have a follow up question about front tire slipping. How do you detect the initial slip? When I was riding on 84 few weeks back I felt like the front just dropped from under me. I was able to save it mainly through luck and not going too fast by straitening the bike. I am assuming that is passed the initial feeling of it starting to slip?
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Old 10-31-2010, 07:12 AM   #40
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Actually I have a follow up question about front tire slipping. How do you detect the initial slip? When I was riding ....... I felt like the front just dropped from under me

I am assuming that is passed the initial feeling of it starting to slip?
Let's see what I can share for you on this question Alex.

---------------------------------------------------------------

First off, it's important everyone reading this thread fully understand that even the slightest amount of front tire slippage in a corner, when riding on wet pavement, carries a serious risk of a crash, no matter the skill level of the rider!

The fact that any front tire slippage (even the slightest bit) does occur, is in most cases a huge red flag of an already big "FAIL" on the part of the rider regarding effectively applying one or more of the traction control techniques mentioned in this thread.

I don't want anyone to come away from this tread with the misimpression that detecting a slipping front tire when riding in the rain, and then making some bike controls to catch it and save it, is a targeted aquired skill. Learning the skill to avoid ever having the slipping front tire in the first place, is the skill I hope to get other riders to learn from this tread (and the practice that follows, after now knowing what to do).

With that said, when things do go wrong, here's my take on the detection of front tire slippage.

Instantaneous detection is the key to a long-shot possible save. Just a few tenths of second will be the difference in an immediate slam to the pavement, vs. some quick adjustments with a butt pucker moment ..... and potentially continuing to ride on.

The key to the following detection aspect is "being incredibly loose on the handebars". Without that, this subtle change in the bike won't be detectable until things are so far gone that a crash is nearly sure.

What I notice when the front tire first begins to slip, are the following things:
  • 1) The direction the front wheel is pointing (and subsequently the position of the handlebars) will suddenly be slightly more INTO the direction of the turn. Kind of like an auto-pilot where someone has slightly rotated the steering in that direction (caused by the reaction of the tire pushing outward).

    2) A recognition that the trajectory of the bike's line of travel suddenly changes, with the line just beginning to run wide. Bascially the direction you're looking through the turn and the direction the bike is just beginning to travel, are suddenly becoming different.

    3) A slight (unrequested) increase in lean angle of the previously near-vertical attitude of the bike.
All of the above are incredibly subtle changes, and require a lot of experience in riding in slippery conditions at pace to even begin to detect early enough to be able to have any chance of reacting and catching. Hence the prevention approach to keeping the front tire from slipping in the first place as being the golden rule!

There are some extremely advanced rain riding techniques that can potentially be applied as a final bullet to try to save a front tire push that's gotten pretty far out there; but as that such techniques are beyond what's in the realm of 99% of those reading the information in this tread I will keep that in the archives for now.

Last edited by Gary J; 10-31-2010 at 07:46 AM..
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Old 10-31-2010, 10:59 PM   #41
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Awesome, thank you. I'll concentrate on the prevention part for now, and file this away for the future. My body position has improved, but throttle control needs work. As Doc Wong rain ride demonstrated, specially going over tar snakes at the end going up 9 to four corners.
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Last edited by UDRider; 10-31-2010 at 11:07 PM..
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Old 11-01-2010, 10:51 AM   #42
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As Doc Wong rain ride demonstrated, specially going over tar snakes at the end going up 9 to four corners.
The secrets I've found for best dealing with tar snakes while cornering, especially when riding in the wet, are as follows:
  • #1: Look far ahead and try to plan out a riding line that avoids as many of them as possible (like picking a path through an obstacle course)

    #2: If it's impossible to totally avoid some tar snakes, and you have to cross over them, do the following:

    - Try to set a line for the bike that will cross over at the greatest angle as possible, to minimize the time the tires spend crossing over

    - Stay loose on the bars and don't fight the outward tire slippage. "Go with the flow", by actually steering the bike (right prior to crossing over) on a path that will run slightly wider; exactly on the path the slippery tar snake wants the bike to go.

    - Keep your eyes focused on looking inward for the turn, to "where you want to go", not allowing the slipping of the tires to redirect your attention to where you "don't want to go" (like across the double-yellow into the oncoming lane!).

    - Make sure to have a light throttle "roll-on" present just prior to, and while, crossing over the tar snake(s)

    - As always in the wet, concentrate on having the bike as vertical as possible while crossing over the tar snake(s)

Once you learn that the slip-n-wiggle sensation caused by crossing a tar snake isn't an automatic sign of an impending crash (if you do all the pro-active steps mentioned above), you'll still need to have great respect for them ....... but not fear them.
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Old 11-03-2010, 02:18 PM   #43
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I don't fear them, but the slip-n-wiggle does make me slightly uncomfortable. At the end of the Doc Wong ride I fell behind as soon as we hit the tar snakes. I reduced speed, but still was slipn on the front. Wasn't worried, but did wonder how the bikes in front didn't seem to have this issue. Maybe I just didn't notice and it felt worse then it actually was.

For roll-on throttle, Doc-Wong mentioned the same thing. So is the idea to enter in to the turn slowly enough so you can continuously roll-on? What about decrease radius turns?

Thank You.
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Old 11-03-2010, 02:42 PM   #44
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For roll-on throttle, Doc-Wong mentioned the same thing. So is the idea to enter in to the turn slowly enough so you can continuously roll-on? What about decrease radius turns?
Occasionally you'll come up on a decreasing radius downhill turn where you just can't keep the throttle on through the whole turn. But they're rare.

It took me a long time to convert to being able to give the bike light throttle through all turns - and you have to do more braking before the turn to do it - but it has made me a better and safer rider by acquiring that skill.
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Old 11-03-2010, 03:45 PM   #45
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From years of mountain biking I learned where my attention needs to be -looking far ahead, and avoiding big obstacles. The smaller bumps/obstacles/slippage are integral parts of riding off road, so I’d let the bike dance under me, over the small stuff, and not waste mental energy on them.

I found myself using the same mental process when I ride mc at night on wet and foggy goat trails, where it’s impossible to see and avoid all the leaves/debris/cracks, etc. My main focus is to make sure I see which way the road is turning, use a sensible entry speed in the turns, keep the bike as upright as possible and being smooth, in a focused but relaxed state, but I don’t worry about the small stuff. Obviously, I see tar snakes on 9 during the day, but when it’s dark and wet, and I’ve adjusted my riding to the condition, I don’t even notice the tar snakes since I don’t need to waste my attention on them.

Edit: I'll admit that during my ride last Saturday night, I couldn't keep up with a truck going down Jamison Creek, and a car on 236 (from the park headquarters toward upper 9), mainly because I coudln't see the road well in the fog, plus I didn't want to risk overriding available traction on two wheels. However, it's generally no problem on the wider/straighter/cleaner roads like 9.

Last edited by Gary856; 11-09-2010 at 08:28 PM..
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