TIRES TIRES TIRES

[srt8-in-largo]

Hope these video work
https://video.search.yahoo.com/video...hspart=vz&tt=b

https://video.search.yahoo.com/video...hspart=vz&tt=b

What's your point here; that tires undergo testing, or CT's can carry a heckuva load, or something else?

We can be certain that CT's mounted on CT rims can handle higher loads but what load can a CT handle when mounted on a MT rim?

...

If everything is equal,,, what is that CT doing to the bike that a MT doesn't that makes the difference in handling?

EXACTLY how is the CT affecting cornering,,, WHY does it require more counter-steer? Why does it create understeer?

THAT is the question so few DS'ers seem to be able to answer,,, (Those who ride MT's don't have to worry about it, so why should they bother with 'understanding' it?)

The Mic is open,,, Lets hear from the DS crowd exactly why CT's handle 'differently'? What do they do to the bike?

Construction, materials, and geometry. Not only is a CT shaped differently than a MT, its' construction is different using different rubber compounds than a MT.

EDIT: The question remains, how do these differences work to produce the difference in handling.

[bob109]

Do any of you DS'ers actually know WHY the bike handles different with a CT than a MT, or do you just shrug it off as an anomaly?

Can any of you explain (and/or understand) exactly why more counter-steer is required? Can you explain exactly what happens differently on your bike when you use a CT?

Sorry for the delay in getting back to you on the valid concerns/observations you raised. In a attempt to answer your questions I had to take some pictures of my 6 with the General G-max. Hopefully they will be of assistance in demonstrating what occurs with a CT when at rest, leaned etc.

First and foremost beyond the obvious difference in a MT's rounded thread/tread profile and the flat thread of a CT, the radial construction is different. My reference to a CT for this discussion is a non-run flat radial which in my case is the G-Max, having a single ply sidewall. The MT have extremely stiff sidewalls which are required to support and hold the curved tread profile in place while cornering and eliminate any sidewall "squirm" which is the first noticeable difference between it and a standard radial CT. The OEM G704 Bridgestone has the following! Thread/Tread 2 Aramid + 4 Nylon....Sidewall 3 Nylon. In comparison the G-Max has Thread/Tread 1 Polyester, 2 Steel, 2 Polymide....Sidewall 1 Polyester.

The extreme "stiffness" of the MT 3 ply sidewall makes the tire ride hard in comparison to the soft 1 ply sidewall of a normal non-runflat.
Herein is the key to the difference in handling. The MT simply rolls off tread center when cornering with zero resistance because of its stiff sidewalls and curved radius. The G-Max in this case relies on the soft 1 ply sidewall to actually "squat" which allows the thread edge to flatten. This actions is what some refer to as "tire squirm" and in reality what is occurring is "sidewall squat" for the lack of a better term.

Most normal non-runflat radial car tires exhibit sidewall bulge. Just take a good close look at any auto or truck which has conventional radials and you will notice the lowest portion to the sidewall protruding beyond the thread edge. It is this normal function of a radial CT which allows it to work on a motorcycle. When cornering with the CT you are actually making the sidewall bulge enlarge in the direction you are turning and the opposite side of the thread which is now "unloaded" has no bulge showing. When uprighted the normal sidewall bulge on both sides of the tire returns. Turn in the opposite direction and the same sidewall action occurs. This action allows the use of the entire width of the thread/tread without ever riding on the sidewalls!

I have some personal preference regarding CT's. First is thread design with a symmetric, directional thread with sufficient sipes for water channeling. As CT carry a Tread-wear Rating a 400 or above is a good start. Maximum Pressure rating should be at least 50 PSI.

One of the most important functions when equipping a cycle with a CT is discovering the "sweetspot" for air pressure. Too high and the tire will tend to break loose in hard cornering! Too soft and the tire will exhibit unacceptable "squirm"! After scrubbing off the mold release agent which usually occurs within the first 50/100 miles I'll adjust the pressure from a starting point of 36/38 lbs. in 2 lb increments. My current G-Max started at 38psi and I finally settled at 41/42 for the "Holy Grail".

I'm attaching some pics of my bike on the side stand. I'm sure if my 250lb. a$$ was in the saddle the "radial tire bulge" would be a bit more pronounced

Attachment 8593Attachment 8594Attachment 8595Attachment 8596

This G-Max has just over 20K of wear. You can note the tread wear is even across the tire face and there is not a sign of any sidewall wear

[DMAGOLDRDR]

[QUOTE=Scotrod;46987]Do any of you DS'ers actually know WHY the bike handles different with a CT than a MT, or do you just shrug it off as an anomaly?

Can any of you explain (and/or understand) exactly why more counter-steer is required? Can you explain exactly what happens differently on your bike when you use a CT?

Or is it "don't know, doesn't matter, don't care?"




I am no expert by any means, but understand how and why. I don't know if I could explain it very well though.
Tire and Motorcycle designers put much effort into tire size, rake and trail to get a Motorcycle to handle well. BUT as many orther aspects of a motorcycle they are very general (such as seat and windshields) The OEM is looking for a good well rounded handling Motorcycle that will fit everyones needs. Tire size and the difference in size front to back changes handleing. Larger tire in the rear will change rake and trail and change the steering effort. So will lowering the rear. Everthing makes a difference.
With two rounded tires, or M/T front and back, as you lean the tire diameter gets smaller and the bike rolls into a corner but slow ever so slightly, which is why riders are always told to ease on the throttle in corners. But a C/T does not get smaller in diameter as you lean so you need to ad input (counter steer) to help the bike lean and go through the corner.
As I reread this I just don't think I can get my point across well. I will have to see what may be written on the subject to help me get my poin across...

[Scotrod]

Scotrod...do you happen to remember what CT you had?

Yup,,, Michelin HE on a VTX1800. Unclear on the exact size, other than the 'recommended' size. (Was also the 'recommended/popular' MFR/model of CT for the bike at the time.)

[Scotrod]

Good efforts so far at 'the difference',,,,

It all boils down to keeping the front and rear contact patch's in line relative to the centerline of the bike.

The front stays relatively 'close' to the CL regardless of lean as its a narrow, 'very rounded' profile tire.

As, for all intents and purposes, the front tire seldom get a huge modification in width/rounded profile,,, It remains a ~constant~ in this explanation

Changing the rear (most common) is where the imbalance is created.

The contact patch on CT (or some 'look at me!' fat azz MT's) will move farther away quicker from the bikes C/L when camber (lean) is added than a OEM sized/shaped MT. In essence, you have the rear tire's contact patch following a tighter line around a corner than the front,,, requiring more counter-steer /, more lean / more 'push' on the front tire than if the rear was 'in line' with the front. Crab steer. All of a sudden, your draggin hard parts,,, not because you are going faster, but because you're leaning farther to correct the understeer.

The worst possible tire with the least amount of lean required to move the rear contact patch the farthest away from C/L the quickest would be a wide, stiff-walled tire with a flat tread face (Example would be a RF CT),

A 'soft wall' CT requires more lean before the 'outside' sidewall starts lifting the tread than a RF,,, but in the meantime, the 'inside' sidewall is deforming/being compressed as the inside rim bead bears down against the tire.

This is where the 'sweet spot' you hear about can come into play,,,, You want just enough air to keep that inner sidewall from turning 'limp' in a corner, but no so much air it remains rigid/lifts the outer sidewall too far. The 'goal' is to get that CT to corner like a MT, by keeping roll/lift to a minimum, and keeping both the front and rear contact patch's as close to in line with each other and the centerline of the frame,,,,, regardless of camber. Something that folks who use OEM sized MT's typically don't have to worry about,,, (We ain't talking about Big Dog bikes, WCC, or other store-bought 'choppers',,,)

Sidewalls on MC tires are stiff as wood. CT sidewalls are limp. Go down to the local Wally World and push in a sidewall with your finger on any display tire. Then go to a Stealer and try to do the same with a MT. No comparison. Much stiffer SW on the MT, which results in consistent tire shape regardless of lean. Combine that with the rounded profile of the MT tread, and you are as close as you most likely will ever be with the rear contact patch following the same line as the front contact patch while cornering.

Skinny front tires and 'look at me' jumbo-wide rear MT tires are equally 'mis-matched',,,, Looks good sittin still at the local bar, but corners like an old pickup truck,,,

Once you wrap your mind around the 'cause/effect' of the CT, RF or NRF, and what it does to the suspension geometry of your bike while cornering, it isn't quite so appealing,,,

[hiflyer]

So to change the discussion up a little, what the heck is going on with my front tire? 11k miles running 40psi, monitored closely. Seems like a weird wear pattern to me.

[Steve 0080]

So, assuming insurance would be ok with it, would warranty service? Can Honda refuse to fix a motor problem or a trans problem because the found a CT (or for that matter you use 15W40 when their manual states 15W30?)
This is my first ever bike that I bought with 0 miles. I do all my work myself, and always have, but got to admit the warranty idea is appealing, I'd just hate to shoot it all to hell cause I have a CT on the bike when I roll it in. Anyone know for SURE what Honda would do?
2~kewl

HONDA dealer did my Progressive suspension install and did not mention the CT on the rear? As far as warranty, take it off before you go in if you feel there will be an issue... I did have an idiot at a dealer tell me because I had drilled the pipes on my Rune, that was the reason the throttle body went bad..... kinda like when I was a child and put shocks on my 1967 Firebird... My Dad asked if it was faster??? Hell Ya!!!

[Steve 0080]

So to change the discussion up a little, what the heck is going on with my front tire? 11k miles running 40psi, monitored closely. Seems like a weird wear pattern to me.

Check the date it was made...short of that...Have you really been keeping a close eye on the air pressure???

[hiflyer]

Check the date it was made...short of that...Have you really been keeping a close eye on the air pressure???

Really!

[Steve 0080]

I have only run two CT's on bikes... The first was a Bridgestone Potenza , The second, is the Michelin Alpine RF..... With the Potenze you did have to counter steer the bike...I did not really like this tire or the feel. With the Michelin, there is no difference that I can feel between it and a MT.

As far as Sweet Spot.... this was explained to me..... get some white shoe polish and mark a line across your tire...drive for 100 feet as vertical as possible...stop and see if the white mark is worn evenly if not adjust accordingly ...

At the risk of this discussion will never end or change anyones minds...we are to old to change our minds.....just sayin