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A big post on tires

In the end, sidewall construction only matters in the terms of the feedback you get. If it works for someone, it works. Getting all strung out about handlebar setup and "THE ROADS ARE SO ROUGH!" is missing the point. If the tire works, the tire works, and if it doesn't, all the namby pambying about what badass riders we are isn't going to change that.

This is why in the end it's best to go out and try the tires.

loumc has the front end of his bike slammed, it's going to make the bike feel wonky and unstable on a triangulated, stiff sidewall tire. I've said this before but I'm pretty sure he has me on ignore, after I dared to mention that dropping the front an inch and a half in the triples is going to kill his trail :laughing He's the sort of rider where it's his way or the highway. That's fine, but I wish he'd learn that his wagon road setup isn't what works best for everyone and every situation. If you're not willing to invest the time and energy is getting a setup for specific tires, then it's a gamble as to if the bike will work well or not on new tires.
 
This is why in the end it's best to go out and try the tires.

How good do I have to be to tell what direction to go on tires?

If I start out on one type, will I be forever ruined for the other?

Would I be a better rider if I get "lucky" and pick and stick with a type of construction that suits me well?

Will I be a worse rider if I pick and stick with a type that doesn't suit me, but be so used to it that I don't feel better on the other type?

Should I care?

I guess I should ask...does anyone switch back and forth between harder and softer sidewalls and go just as fast on either?

Personally, I'm inclined to just make the best of what I have...and I think it will be a while before I could accurately asses how I were to perform on each type, and if I liked them or not. So this is all just theory to me, for now.
 
You know, what I'd like to know from your perspective is, what do you specifically get from having a more compliant tire for your specific type of riding.

Is it the mechanical traction you get, which might be more easy to emulate with a stiffer tire, but a more compliant suspension, in theory...

Or is it the feedback you get from the tire, which might be far more sensitive to tradeoffs in compliance in various suspension components.

My suspicion is that it's harder for riders to account for traction feedback information that's outside of their comfort zone than it is for an engineer to provide the same level of mechanical grip while shuffling parameters around.


So my question to you is, are you looking more for your tire to simply provide grip during the periods of time it's actually in good contact with the ground, or are you also reading precise traction information as well? (During cornering specifically).

I ask because I wonder if instead of tiptoeing around in fear of losing traction in the first place, if you deal with traction issues on the "backside" so to speak, and just deal with loss of traction after the fact, because you know it's going to happen, and it makes more sense to "fix" it then, and get on with not being too cautious into the next corner.

I'm not sure if I'm making any sense here. I guess I wonder if some people care more about traction information telling them how it *IS* going away, as opposed to traction information about how it *MIGHT* be about to go away.

As well as the difference between entering a corner specifically intending to maintain grip throughout it, as opposed to entering the corner focused on the directionality of your exit, being more concerned with getting your direction of travel as a whole changed, and viewing the loss and return of grip throughout that process as incidental.

Good Question, very complex, but if it wasn't, it wouldn't be a Question.
I'll just start with the first line and see how far I can go.

Line1. What I get is tire hook-up. The Pirelli Diablo Corsa III's stay in contact with the roughness of the pavement that is very variable in it's roughness.

A stiffer side wall, say Dunlop or Michelin, will (now this is like at a molecular level to maybe a 1/64th of an inch of action between the tire and the pavement) will be lifting off high points, instead of just stayin down.

Compare it to dribbling a basket ball. Full air pressure, the ball is hard, drop it and it bounces nearly as high as it was dropped from. Let the air out, drop it, it hits the floor, plop, no bounce what-so-ever.

Now keep in mind both front and rear tires are soft sidewalls. I don't depend on either tire staying hooked up, its just easier, the more they are.

The front one, will get lofted, under power, or a combination of power and a little bump assist. So that has to go on with no effect. That just requires a certain lean for the speed and arc of the corner, like a uni-cycle rider.
Dirt riders pick this up real fast, because of their sketchy traction.
The Rear wheel can loose traction, (can is an understatment, count on it loosing traction) but, for the most part (rarely a bad thing) it's a good thing, helps drive the bike into the corner (that's how flat trackers go around a dirt corner at 100 mph on a mile track). These Track day/Dot, street tires, are beautifully controllable. All they ask is that you the rider, give them a chance, Don't do all the wrong things.

Use Your sight line, see what your getting into. Know what You can do, do it ahead of time.



Line 2. Stiffer tire, more compliant suspension.

That's not quite right. You choose a suspension, say Ohlins but there are quite a lot of options, that is working through out its range, for the job at hand (say prepaired surface road race track, or public road, and we all know what that can be) as oppose to the other jobs which require more travel, and I'm not writing a book just some posts.

But You choose a suspension, that's correct springs for the weight of you with gear, and your bike. There is no stiff or more complient, there is only correct.
You have (if necessary) shim stacks chosen to give the desired controls during the travel. Both in distance of travel and speed of travel. There is no stiff or more complient, there is only correct. You have a job that needs to be done. It either gets done wrong or it gets done right.

Fine tuning of those controls are what the compression and rebound settings do. That gets into a specialists territory, go to them.


The rest of the Question for now anyway I'll lump into feedback...I get that from the tires, and concentration. A light touch on the handle bars, lets it come through.
 
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How good do I have to be to tell what direction to go on tires?

Depends from rider to rider.

If I start out on one type, will I be forever ruined for the other?

Depends on what you mean by "ruined". I prefer some tires for some situations, and other tires for other situations. I don't call that ruined, I call it aware.

Would I be a better rider if I get "lucky" and pick and stick with a type of construction that suits me well?

What makes a better rider? In my mind, one that has a good understanding and ability to apply that understanding in all of the aspects of motorcycling is a good rider. Thusly, the more tires I ride on, the better I get.

Will I be a worse rider if I pick and stick with a type that doesn't suit me, but be so used to it that I don't feel better on the other type?

Would you willingly adjust your suspension wrong to have to learn to ride around it? There are lessons that you can learn by riding around a problem, but chances are, if you have a problem, you'll be best off just trying to solve it.

I guess I should ask...does anyone switch back and forth between harder and softer sidewalls and go just as fast on either?
Yes. I've run roughly the same times at the track (2:04 range at Thill on an SV) on Pirellis, Dunlops and Michelins. I've gone nearly as fast on a friend's 600 with Bridgestones. I get different feedback from each set of tires and it changes my comfort zones for a given corner. I felt very comfortable midcorner on Pirellis and Dunlops, so I'd carry more lean through the corners, but I felt better on corner entrance and exit on the Michelins.

Personally, I'm inclined to just make the best of what I have...and I think it will be a while before I could accurately asses how I were to perform on each type, and if I liked them or not. So this is all just theory to me, for now.

So next time you have to buy a new tire, make it something different. What you've ridden is the best you've known. This is why I have a hard time taking people who swear by a single tire seriously...I swore by the Dunlop 208F when I first started riding because I just flat out didn't know any better. It's a tire that takes a long time to warm up and then sticks really well and holds it's line hard. Switching to Pilot Powers was a revelation in another world of tires, one that was responsive and could change line midcorner with a light input to the bar.



loumc, your analogy is flawed because that tire that is stiff is also going to have rebound after it hits an imperfection to attempt to mesh with the ground again. A soft tire will deform to the ground, but a so will a stiff tire, just in a different fashion. Your analogy is backwards, there's no "bouncing back up into the air" because that stiff sidewall is stiff in both directions.

Furthermore, contact patch deformation and sidewall deformation are 2 different things. You can have a stiff sidewall with a soft belt construction and a soft sidewall with a stiff belt arrangement. One does not always go hand in hand with the other.

But You choose a suspension, that's correct springs for the weight of you with gear, and your bike. There is no stiff or more complient, there is only correct.

What is "correct"? It's stiffer or softer depending on the rider and the riding style! I've had to change spring rates away from "correct" because I was pushing the front end too hard and it was bottoming out. You can baseline a setting based off of someone weight and bike, but that doesn't make it correct for a given rider. My SV was right for the track and wrong for the street, so I changed the bars by simply changing where I rode.

You can't lay down these flat out laws about how xyz is best. Xyz works for you. Expecting that it'll work for someone else ranges from silly to dangerous when people don't have the skills to understand what it means to rob all the trail out of their bikes by slamming the front end.
 
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loumc has the front end of his bike slammed, it's going to make the bike feel wonky and unstable on a triangulated, stiff sidewall tire. I've said this before but I'm pretty sure he has me on ignore, after I dared to mention that dropping the front an inch and a half in the triples is going to kill his trail :laughing

I don't have you on ignore, I might be concerned that your having a stroke or something needing medical attention, though.

My front end is not slammed. I have said I dropped the triple clamps 5/8ths of an inch. I hope you never get any craftsmen that can't tell the difference between 5/8ths of an inch, from 1 1/2 inches do any work for you.

I've used Pilot powers (triangulated, stiff side wall) Metzelers and Pirelli ( Non-triangulated, soft side wall) feed back is not the issue between these tires for me, The triangulated profile isn't right for the corners here. The stiff side walls (well I've already described why they aren't right on rough roads).

There is nothing wonky or unstable showing up, 140 is what I've taken it to and that's my limit for the conditions, stable as a rock at 140, but what do I know I'm only the one one it :cool Now For Gods sake, call 911 and get a medical check up :rofl
 
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It doesn't have to do with straight line stability, it has to do with the bike stability while leaned over, specifically as you drive off the apex. If you're not at track levels of lean it's less of a concern, but still not something that I'd recommend personally.

I'd forgotten how much you changed the front end, but 16mm is a pretty extreme change in ride height on the front. Obviously, everyone's different and for some people it works and for some people it doesn't, but I find it hilarious that you claim there is a "correct spring rate", and follow that up by recommending a massive change in ride height and trail from stock. :laughing

You haven't explained anything, you've just said that a stiff sidewall is like bouncing a basketball, which isn't an explanation of anything, because it doesn't reflect what actually happens in a tire as it meshes with the ground at all. There's no way for a tire to "bounce back up in the air" after rebounding because the tire is stiff in both directions.

And I have no idea what you're talking about with this stroke business. Your posts are getting really incoherent, though, maybe it's time to go for a ride. :thumbup
 
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I imagine part of that may be the 180 rear tire, as it's a bit shorter than a 190/55.
 
: .... there are definitely such rough roads up in the Santa Cruz mountains that I avoid - clearly a sportbike doesn't have the suspension travel to really soak up the bumps in that type of road and frankly I don't want to stack the bike or bend the wheels. ymmv...
You're so right about the choice of bike for extreme road conditions Alex! You're also right about some roads in the SC mountains being best to avoid if you're on the wrong combination.

The very narrow, tight, twisty, poorly maintained "China Grade" is a prime example. This is a shortcut off Hwy 236, that begins a bit out of Boulder Creek.

The deep potholes (2"-3" deep!), that are very hard to avoid (impossible if a car's coming from the other direction at the wrong moment), will definitely bend a rim on a full sportbike. This will occur regardless of brand/model tire, as long as it's a standard low-profile (120/70) radial tire up front. Seen a few bent rims first-hand, to know it's true.

The only bikes that won't bend a wheel are those that have some combination of long-travel suspension, spoked wheels (more "cush") and taller profile/stiffer sidewall tires.

Rider skill has nothing to do with a bent rim, or not, on such roads. It's purely a matter of exceeding the intended limits of the equipment, for the conditions.
 
I guess I should ask...does anyone switch back and forth between harder and softer sidewalls and go just as fast on either?

I would offer if I may a piece of my own experience that involves sidewall stiffness and tire feedback. Take it with a grain of salt as your own experience will beat anything you are told by someone else. I would also welcome anyone else's ideas in this specific regard because I'm constantly trying to learn about this too but historically I only learn the "ouch" way.

A soft flexible sidewall can be a great thing in a high grip environment like a road race track because at the moment that you ask more of the tires than they can offer, they respond in a way that can excite and stimulate you while keeping you on two wheels. The Diablo SC 3 is what I have the most experience with and at the limits of traction they begin to wiggle a bit and it's most noticeable when you are using the area from the web of the thumb / fingers out to your last knuckle to control the bars. When using your palm to control the bars (eg under hard braking) it's not quite as easy to differentiate between that feedback and unevenness in the road surface. For the rear, one idea is to use your legs to lift some of your weight off of the seat and your feet become the traction sensors. But both the front and rear tire begin to move under you just at the limit and before a loss of traction occurs. Grip mostly feels the same as a harder sidewall, but loss of traction feels quite different between the two.

In a low grip environment, a softer sidewall could mean danger. For example, in the rain you should care about feedback just as much as you do in the dry, if not much more. The limits of traction are more readily "reported back to the rider" with a stiff sidewall than with a flexible one. When you break traction with a stiff sidewall (mine would be an Avon Distanzia) you can tell almost immediately and there is just a bit more time for you to react, via body positioning or countersteer, etc. With a soft sidewall, the tire tends to give in the sidewall area just a bit before you lose traction, so that by the time you feel the back end step out for example, the rear tire has already begun a return to it's natural inflated shape and will not start to regain traction until it has finished doing so. That grace period where the tire attempts to regather composure without delivering traction could put you on your butt very quickly.

It's worth noting that on no grip or "near no grip" surfaces like sand and gravel there is almost no difference between a stiff or flexible sidewall because there isn't even enough traction to bend a soft sidewall. All tires suck here, slow down first and you'll come out smelling like a rose.
 
I would offer if I may a piece of my own experience that involves sidewall stiffness and tire feedback. Take it with a grain of salt as your own experience will beat anything you are told by someone else...

Thanks for your input!

I like what you said about using your feet to feel traction by raising up off the seat a bit...I've been working on riding with my weight off the seat recently and I really like what it does for my riding, and feedback.

My feet end up numb though, from the vibes :laughing

Now for even more fun, does anyone disagree with anything netjustin said? Why? How? What? Are we there yet? Thankyou. :teeth
 
I like soft sidewall tires in the rain. I feel like they only give me the feedback that I need, whereas the stiffer sidewall ones will almost tell me too much, I don't need to know exactly what's going on, I just need to know if it's going to slide or not. :laughing
 
thanks for this !!!

I just picked up a foookin nail in my tire (new tires too grrrr, well the bike only has about 4k miles on it) so i was out shopping new tires and came a crossed this.
 
thanks for this !!!

I just picked up a foookin nail in my tire (new tires too grrrr, well the bike only has about 4k miles on it) so i was out shopping new tires and came a crossed this.

Glad to hear it helped you out :)
 
great thread. thx folks!
 
Seems like soft carcass tires function more actively as part of the suspension. Does that also mean they are more sensitive to pressures and suspension settings, ie need more work to dial in on a given day?
 
When should I replace my tires?
If they show any cracking or splitting, or if they are more than 5 years old. Tires will lose grip over time, even if they're just sitting, as they age and dry out. This can be especially dangerous to novice riders who don't have the experience to know that their tires are done, and inevitably ends up with them crashing, sometimes multiple times, before realizing that it's not that they're doing anything wrong, it's that the tires have turned into stone masquerading as rubber. Check your date codes, you'll be amazed at what is sold as "new".

Saw this thread was back, just wanted to say thanks for this. I didn't see this factor in any of the (many) articles/posts I read before buying a bike. I bought my bike from a guy who had bought it cheap, gotten it running, and sold it to me 'ready to go, man' with pre-2000 tires on it. Not blaming him, just saying I didn't think about old tires as a hazard until reading your post. Thanks for saving me some skin. :thumbup
 
Saw this thread was back, just wanted to say thanks for this. I didn't see this factor in any of the (many) articles/posts I read before buying a bike. I bought my bike from a guy who had bought it cheap, gotten it running, and sold it to me 'ready to go, man' with pre-2000 tires on it. Not blaming him, just saying I didn't think about old tires as a hazard until reading your post. Thanks for saving me some skin. :thumbup

I just bought a 2002 Honda that had 4700 miles on it... and the stock BT056's.
I hemmed and hawed about out-right replacing the tires because their date stamp was ~9 years old.

I decided to ride themup Hamilton/ Mines with no ill effect.
They seem to stick fine for my B pace, but knowing they're old is in the back of my head ( and right hand. )

may2_2010_2.jpg
 
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