BARF - Bay Area Riders Forum

Go Back   BARF - Bay Area Riders Forum > Moto > General


Notices

Reply
 
Thread Tools Display Modes
Old 07-23-2009, 09:04 PM   #1
Z3n
Squid.
 
Z3n's Avatar
 
Contributor +++++ 2%

Join Date: Feb 2005
Location: Oakland, CA
Motorcycles: help me prove my commitment to Sparkle Motion.
Name:
A big post on tires

First: A disclaimer: I am not a rep for any tire company, and I'm still far from an expert. I've run a variety of tires at trackdays and races, as well as street riding, and spent some time in schools learning about compounds, construction, and profiles, and have experienced the differences on the track, as well as listened to the opinions of other riders as they changed brands. The intent of this thread is to help riders understand the difference and potential gains for between different brands of tires, and to offer a quick course on the different types of construction and setups, and how that can change rider feedback. None of this should be taken as gospel, or the One Truth of tires. It's just what I've learned over my years of riding.

If I've missed something, made a mistake, or skipped over something you feel is important, please, bring it to my attention. If you'd like to cross post this elsewhere, feel free to do so, all I ask is that you credit me and let me know via e-mail, PM, or the thread so that I can improve it with other people's feedback.

What do the numbers mean?
When dealing with tires, you will often see alphabet soup on them, for example:

120/60ZR17 Michelin Pilot Power

First, the 120 is the width of the tire in milimeters. The 60 refers to the height of the tire, as a ratio of width. So the tire is 120mm wide, and 72mm tall. The ZR is the speed rating, in this case, 149+MPH. The 17 refers to the rim size, in this case, 17 inches, a fairly standard sportbike front tire size.

The other main number of note on the tire is the date code, example in the box below:


The first 2 letters are the week that the tire was made, the last 2 are the year that it was made. This tire was made on the 3rd week of 2005. If there's only 3 numbers, it was made before 2000, which means the tires are ancient and should be replaced immediately. On motorcycle tires, the numbers are usually in their own oval without any letters preceeding or following.

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".

What sizes should I run?
120/60 or 120/70? You will have no problems running the 120/70. The taller profile will improve contact patch while leaned over. The only thing to be aware of is that you may have to adjust your fender to get the tire to clear. Just check the tire for any signs of rubbing after you put it on. Check again after your first ride, as tires do expand somewhat under use.

How much wider can you run the rear tire? In general, not more than one size up. For those with 160 tires on the rear of their bike, looking for a "fatter" look, do not go over a 170 profile. A 180 will be squished on the rim and will flatspot and wear quickly, as well as reduce contact patch while leaned over. For track use, some makers offer 190s for a 5.5 inch rim and 200s for the 6 inch rims. Tire size in this area will often turn into personal preference, try the sizes recommended by your tire guys. At worst, you'll learn you don't like it.

What pressure should I run?
There's not one catch all answer here. Each motorcycle will recommend a different pressure. Some bikes can recommend as low as 26F/26R, others can recommend as high as 38F/42R. In general, the baseline that most agree on for standards and sportbikes running modern radials on the street tends to be around 32-34F/34-36R, depending tire construction and the weight of the bike. The big bikes will run higher pressures to compensate for the additional weight.

Tire Construction
Tires can vary in 2 major ways. The first is sidewall stiffness, the second is profile.

Sidewall Construction
Brands that have a soft sidewall: Metzler, Pirelli.
Brands with a stiff sidewall: Dunlop, Michelin.
Bridgestone is an intermediate construction.

So...what does that mean to you as a rider? Soft sidewall tires will flex more as they encounter imperfections in the road. This additional squish zone will act as an additional damper in your suspension, which can make bumpy roads and tracks feel smoother. This can also help calm down bikes that are set to be particularly twitchy, as the tires prevent minor bumps from getting through to the suspension and chassis. Especially noticible while leaned over, where your suspension is at it's least effective.

Soft sidewall tires will also flex more under load, increasing the heat that the tire builds up through use. Most soft sidewall tires will run higher pressures as a result. If you're running a soft sidewall tire, sometimes you'll find that under heavy use, the tires start to feel numb, or under commuting use they wear and flatspot quickly. If you discover this behavior, bumping up the pressures will often solve the problem, as chances are good that the tire is overheating. Pirelli Diablo Corsa 3s are particularly well known for this, prefering pressures of 34F/36R even for track use, and sometimes upwards of 36F/38R for street use, even on supersports.

Stiff sidewall tires will provide more feedback from the road in every way. They don't have the insulating effect of the softer sidewall tires, and as a result can exacerbate twitchy handling characteristics, but they tend to give more information in general. Michelin and Dunlop race tires can run as low as 18R in some cases.

This isn't to say that one system is superior to the other, but people may find that one or the other works better with a given suspension setup, and switching between the 2 may require a change in setup in order to get the ideal response from things.

Profile Construction
There are 2 types of profile construction: Triangulated and rounded.

In general, the tire profiles by maker look like this:
Triangulated tires: Michelin, Dunlop
Rounded: Metzler, Pirelli, Bridgestone

Triangulated tires will help the bike feel lighter on it's feet, turn in quicker, and respond well to midcorner line changes. Some will feel that triangulated tires feel flighty and more prone to headshake.
Rounded tires will require more steering effort, but will also hold a line more consistantly and tend to feel more planted, and can help calm down a bike that's prone to headshake. Mid corner line changes will require a good amount of input to the bars. Some will consider these tires "sluggish" and "heavy".

Compound
In general, you want to use the hardest compounds you can get away with. On the track, using softer tires when you can't exploit the grip will just result in quick wear and inconsistant grip levels as the tires go off. The major exception to this is the front tire on low HP bikes, where you'll probably be running the softest compound no matter what, as there's simply not enough hard braking to push the front into needing a harder compound. Your tire vender will have the best advice given the conditions and the track abrasiveness.

For street use, it's worth taking into account that more street/track oriented tires will tend to perform much more poorly in cold/wet conditions than sport touring tires. This also applies when the tire has not been brought up to temperature yet, and is another reason that it's prudent to stick with sport touring tires if your bike is going to see commuting more than the track.

Sizes, revisited
Different brands of tires can have significantly different physical sizes, even if they're both marked as the same size. Ideally, you measure both tires, inflated and on the bike, and see how much things have changed. Some will religiously adjust their ride height for these changes, some will not. I tend to leave settings alone and go out there and see how the bike works before changing things.

Breaking in tires
Cold tires are slick. New cold tires are doubly slick. There is no longer any mold release used in the molds, however, the tires still have a very uniform surface out of the molds which will reduce available traction. On street use, one decent ride where the tires get warm and you slowly work up your lean angle will have your tires completely broken in. The trick is to slowly increase lean angle so that at no time while you're leaned over is your entire contact patch in the smooth section of the tire.

On the track, I've tossed on new tires, done the warm up lap, and gone racing. The very abrasive nature of a track helps the tires break in much faster. If your tires will come up to temp in a lap, by the end of the second lap your tires will be more than ready to go.

Heating up tires
The most common claimed reason for crashes is usually "cold tires". However, there's more to it than that. Not only do you tires have to come up to temperature, your rims and suspension must come up to temp as well. Cold suspension will react slowly, causing harshness, poor handling and potentially a loss in grip as a result. A hot tire on a cold rim (for example, on a windy day with tire warmers) can cause what feels like a sudden loss in available grip when the warmers come off and the rim begins to leech the heat out of the tire.

With that said, a cold tire crash is actually a failure of the rider to accurately account for the conditions, and never the fault of the tires.

How do you know if you have the right pressure? What you're looking for an increase in the range of 5-7 pounds from cold to hot. If you're getting too much increase in pressure, you need to boost your pressures to reduce the amount of flex in the tire. If you're getting too little increase, you need to reduce your pressures in order to get more flex and heat in the tire. While rubber balling up on the tire is fine, you don't want any tearing or gouging in the tire. Tearing and gouging can indicate either a problem with suspension, pressure or tire compound. Consult your local suspension expert and tire guy.


Weaving to heat up tires
Bullshit. Motorcycles simply do not generate enough cornering load when weaving to build heat in the tires. The only way to get tires up to temp is to flex the carcass, with heavy throttle and brake use. If you want to get your tires warm, don't weave back and forth but instead speed up and slow down, accelerating heavily through first/second gear and braking heavily.

You will still see riders weave for 2 reasons: To feel out the bike, and to scrub off the tires.

Heat Cycling
Each time you heat cycle your tires, you leech out some of the internal oils that help a tire stick to the ground.

Now, this is not a concern for the all but 1% of street riders, who will probably already be aware of this. I know a very select few who do nothing but ride twisties, and ride them hard. Usually their fronts start to go off at around 5k, while they still have what appears to be good tread on them and they're almost done with their second rear tire.

On the track, the primary use of tire warmers is not to keep you from ending up on your head on the warm up lap, but to prevent heat cycling. By using tire warmers, you can help extend the life of your tires. However, you also have to be aware that you can cook your tires by leaving your warmers on high all the time.

Personally, I don't use tire warmers. If it's sunny, I park the bike with the sun as full on your tires as possible. I've discovered this allows me to be more comfortable on the warmup lap. That doesn't mean I ignore my warm up lap, it's just an easy thing that helps keep the tires warm.

When I'm racing, at my 2nd call I'll go do laps in the hot pit, accelerating through first/second gear and braking hard. After 8-10 passes, my tires will be mostly hot, after doing my outlap at around 85% speed for the first half and 95% speed for the second half, the tires are completely warm and I can go hard straight off the launch without worrying about things. This is probably overkill, but I like the security and the additional time to warm up my tires and suspension, as well as the time on the bike to feel everything out.


Mixing and Matching Tires
Mixing and matching tires is usually fine, as long as you have the awareness of what you're doing. Ideally, you want to mix tires that have a similar design and construction, so try and group them according to sidewall stiffness. You will change the handling of the bike by doing this. It may be a positive change, it may be a negative one. It's up to you to safely feel out those changes.

I have tracked my SV with a Dunlop 209GP (Euro) on the front and a Pirelli Diablo Supercorsa on the rear. Doing this taught me more about how tire construction affects a bike than any words or explanation or paired set of tires ever could have. I could get on the gas and feel very clearly the difference between the stiffer front tire and the softer rear tire. In my case, it maintained a lot of positive feedback from the front for confidence while trailbraking while removing what I felt was unneeded feedback from the rear, as well as keeping the bike more stable and less twitchy over bumps. This was at an A group pace. I don't know how noticible the differences are going to be and how much gain someone would see from doing this at a slower pace.

As long as you have some understanding of what you're getting into (I knew I'd feel the rear move around differently from the front), there's nothing wrong with mixing and matching tires. The only other words of warning about mixing tires I'd mention is that some makers claim that their tires have specific siping on the tires that are designed to work together as a matched pair to move water out of the way. If this is true, I've never ridden hard enough in the rain to notice, but it bears consideration.

Plugging vs. Replacing Tubeless Tires
On this front, I feel it's fine to patch a tire internally. However, I'd avoid plugging something near the sidewall. I've helped people limp home with the rope type plugs in their tires, to some success (they got home, it usually still leaked some air).

Other people will disagree and say that any plug is asking for trouble. I'd be fine with a plugged tire for commuting or casual twisty use. I wouldn't use one on the track. I have seen people use plugged tires in the C group on the track without any problems, however.

Tire Choices (Street)
My general recommendation for daily riders is Sport Touring tires. If you've got a bike that's doing double duty on the track and street, or is purely a weekend pleasure ride, then Street/Track tires are a good choice.

Tire Choices (Track)
For C group, as long as your tires area in reasonably good shape, you can run just about anything. For your first trackday, Sport Touring tires are fine, although you'll probably have more fun with some Street/Track tires.
Once you move into the B group consistantly, my recommendation is to run at least DOT Race tires. While a skilled track rider can ride Street/Track tires at an A pace, they're not pushing their limits, they're going to be well within their personal limits and will be able to handle the tire potentially misbehaving and sliding around. As you improve, you won't have to worry about suddenly exceeding the limits of the tires after a particularly good session and having them go off on you, perhaps with drastic consequences while you are pushing your limits. The other advantage is that DOT Race tires go off much more smoothly and slide more consistantly than Street/Track tires.

Bias Plies
The only Bias Plies left are pretty much the best of the bunch, so if you've got a bike that still runs them, you pretty much can't go wrong with any of the offerings from major tire makers. I'm partial to Pirelli Sport Demons, personally, but have seen the 250 guys absolutely hauling ass on the bridgestones as well. The rest seem to be lower in popularity for whatever reason.


Tire type rundown
Pirelli
Sport Touring, newer design to older:
Diablo Rosso, Diablo Strada, Diablo(OLD)
Street/Track
Diablo Corsa 3
DOT Race
Diablo Supercorsa, Dragon Supercorsa

Metzler
Sport Touring
Z6 Interact, Z6
Street/Track
M3, M1
DOT Race
Racetec

Michelin
Sport Touring
Pilot Road 2, Pilot Road, Pilot Sport(OLD)
Street/Track
Power One, Pilot Power 2CT, Pilot Power
DOT Race
Power One, Pilot Race
(They make the Power One in both a "street" and a "race" compound)

Dunlop
Sport Touring
Roadsmart, D220
Street/Track
Qualifiers, 209F
DOT Race
211GP(Euro/Ntec), 209GPA (Euro/Ntec), 211 (US, non-ntec)
(Although the 211 (US) is technically a "newer" tire, the Ntec is the prefered tire)

I covered the tire types from memory, so apologies if it's a bit off, feel free to correct me.

Flame suit on, here we go...

Last edited by Z3n; 02-06-2010 at 07:37 PM..
Z3n is offline   Reply With Quote
Old 07-23-2009, 09:21 PM   #2
rsrider
47% parasite 53% ahole
 
rsrider's Avatar
 

Join Date: Apr 2003
Location: earth; for now
Motorcycles: 2014 Monster 796 -- 2012 Ninjette -- 2001 Triumph Sprint RS -- 2013 Vespa GTS Super 2019 Ninja 400
Name: Toast
hmmmmm
rsrider is offline   Reply With Quote
Old 07-23-2009, 09:26 PM   #3
GPzPop
Ask me about my B-1-D
 
GPzPop's Avatar
 
AMA #3295113
Contributor ++ 2%

Join Date: Nov 2005
Location: L i b m o
Motorcycles: zzr & xsr
Name: Simon
Yes but which oil should I use in my first bike, a turbo-busa???

(I keed!) Nice write-up

--S
GPzPop is offline   Reply With Quote
Old 07-23-2009, 09:30 PM   #4
rumpofsteelskin
friend to spiders
 
rumpofsteelskin's Avatar
 
Contributor

Join Date: Nov 2004
Location: Seattle
Motorcycles: bicycle
Name: ******!
Dear Tire Pimp,

Why do the otherwise terrific Avon Gripsters on my DRZ suck in the rain more than any other tire I've ever used? I thought those limeys lived under water.

Your assistance is appreciated.
rumpofsteelskin is offline   Reply With Quote
Old 07-23-2009, 09:31 PM   #5
Z3n
Squid.
 
Z3n's Avatar
 
Contributor +++++ 2%

Join Date: Feb 2005
Location: Oakland, CA
Motorcycles: help me prove my commitment to Sparkle Motion.
Name:
Quote:
Originally Posted by GPzPop View Post
Yes but which oil should I use in my first bike, a turbo-busa???

(I keed!) Nice write-up

--S
Pull the old stuff out of your car and dump it in the bike. It's like tire warmers for your oil.

Quote:
Originally Posted by rumpofsteelskin View Post
Dear Tire Pimp,

Why do the otherwise terrific Avon Gripsters on my DRZ suck in the rain more than any other tire I've ever used? I thought those limeys lived under water.

Your assistance is appreciated.
Move to Santa Barbara. We've already gotten our one day of rain for the year, problem solved!
Z3n is offline   Reply With Quote
Old 07-23-2009, 09:43 PM   #6
Yakoo752
USN
 
Yakoo752's Avatar
 
AMA # 3164290
Contributor ++++++++++ 2%

Join Date: Dec 2008
Location: Cupertino
Motorcycles: M900
Name: Mateusz
.... but you left out Bridgestones
__________________
IMPERIUM NEPTUNI REGIS-Member of the Barf Chapter of the Ancient Order of Trusty Shellbacks
Yoshida Kogyo Kabushikigaisha
Team Triple Threat
Cygnus 12.02.10
Yakoo752 is offline   Reply With Quote
Old 07-23-2009, 09:44 PM   #7
originalsturge
litre bikes are fun
 
originalsturge's Avatar
 
Contributor
Barf Roadside Angel/ Contributor +

Join Date: Jun 2005
Location: Nomad in the USA
Motorcycles: 13 RC8R touring edition
Name: Dan Sturge
Nice write up. Makes a few things more clear to me now about tires.
__________________
"No it's not my blood, I hit a deer."-me

If it wasn't for capital punishment, there wouldn't be a Christian religion.

"The people of the Night understand that the world is a toilet and if you find something that makes you happy before you're flushed, more power to you." Eldritch

"To wave to existing riders is like saying good to see you and hopefully we cross paths again. An agreement that neither rider will do anything to endanger such future passing."-withonor
originalsturge is offline   Reply With Quote
Old 07-23-2009, 09:47 PM   #8
Z3n
Squid.
 
Z3n's Avatar
 
Contributor +++++ 2%

Join Date: Feb 2005
Location: Oakland, CA
Motorcycles: help me prove my commitment to Sparkle Motion.
Name:
Quote:
Originally Posted by originalsturge View Post
Nice write up. Makes a few things more clear to me now about tires.
Glad to hear all that typing wasn't in vain!

Quote:
Originally Posted by Yakoo11 View Post
.... but you left out Bridgestones
My shame: I've never run bridgestones. Only the shitty OEM ones, and it's not fair to judge a tire company on that. I'll buy some bridgestones for the streetbike next..then I have to find some takeoffs to try them on the track...and...and...
Z3n is offline   Reply With Quote
Old 07-23-2009, 09:48 PM   #9
Lovedoc
That's COLD, Brrrr
 
Lovedoc's Avatar
 
Contributor + BB

Join Date: Feb 2007
Location: x
Motorcycles: 5
Name: Biff
Thank you, OUTSTANDING synopsis, I didn't know half that shit.
Lovedoc is offline   Reply With Quote
Old 07-23-2009, 10:05 PM   #10
Flying Pig
Still learning to ride
 
Flying Pig's Avatar
 
2011 Barf Slow Race Winner
Contributor + 1%
Barf Roadside Angel Contributor

Join Date: Jun 2009
Location: San Jose
Motorcycles: One with two wheels.
Name: Solomon
Wow. I learned a lot
Flying Pig is offline   Reply With Quote
Old 07-23-2009, 10:18 PM   #11
Cycle61
What the shit is this...
 
Cycle61's Avatar
 
Contributographer

Join Date: Apr 2008
Location: East of the snow
Motorcycles: yes
Name:
Quote:
Originally Posted by Lovedoc View Post
Thank you, OUTSTANDING synopsis, I didn't know half that shit.
+1

Makes a lot more sense now, the incredible range of tire pressures I was seeing and hearing about this weekend.
__________________
TPW

Washington sucks and it rains all the time.

If I didn't hurt your feelings, then I retract my apology. - bruceflinch
Cycle61 is offline   Reply With Quote
Old 07-23-2009, 10:37 PM   #12
VanyDotK
+5 HP decal
 
Contributor

Join Date: May 2004
Location: Sac / San Jose
Motorcycles: 05 Yamaha R6
Name: Vany
nice, this should be sticked in the newbie section
VanyDotK is offline   Reply With Quote
Old 07-23-2009, 10:38 PM   #13
SOLAR ZX-10R
Veteran
 
SOLAR ZX-10R's Avatar
 

Join Date: Feb 2008
Location: ...rather be ridin'..her
Motorcycles: are simply Irresistible!!
Name: Solar
Thanks for very helpful information

Any other informations...like oil, brakes, major service lists, etc...pls.
__________________
UNITED WE WILL RISE...IF NOT WE WILL FALL.....


1GOD4ALL & BLESS US ALL................................
"Man, he is constantly growing but when he is bound by a set pattern of ideas or way of doing things, that's when he stops growing.".....Bruce Lee
SOLAR ZX-10R is offline   Reply With Quote
Old 07-23-2009, 10:57 PM   #14
TheRiddler
Riddle me this.
 
TheRiddler's Avatar
 
AMA #: 1099639
Contributor + 1%

Join Date: Apr 2007
Location: California
Motorcycles: Any of the two-wheeled kind.
Name: Matt
Too lazy to cut this out but you said:

"Sidewall Construction
Brands that have a soft sidewall: Metzler, Pirelli.
Brands with a stiff sidewall: Dunlop, Michelin.
Bridgestone is an intermediate construction"

Are you sure? I've changed all of the above on and off rims. Dunlop is stiff, and Pirelli is soft. But Michelins have also been soft (Powers), Metzlers have been stiff (M-3), and the Bridgestone BT021 has the stiffest sidewall of any tire I've ever had to deal with.
TheRiddler is offline   Reply With Quote
Old 07-24-2009, 12:10 AM   #15
Yakoo752
USN
 
Yakoo752's Avatar
 
AMA # 3164290
Contributor ++++++++++ 2%

Join Date: Dec 2008
Location: Cupertino
Motorcycles: M900
Name: Mateusz
my thought... it is Z3N's interpretation of sidewalls
__________________
IMPERIUM NEPTUNI REGIS-Member of the Barf Chapter of the Ancient Order of Trusty Shellbacks
Yoshida Kogyo Kabushikigaisha
Team Triple Threat
Cygnus 12.02.10
Yakoo752 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -8. The time now is 05:25 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.