1975 KZ 900 , ZRX Swingarm, 89 GSXR front end

Mark:

Roller will be in the mail Friday AM.

Thanks.

tk11b40 wrote:

OK tire discussion all done now...

you win.

Do I get a medal for coming in first??? :laugh:

Really, I do enjoy this thread more for the bike than the tire discussion. Looks good.

yes you receive the "purple heart".:S

Now.... on to better things,

I plan on finishing the rear brake stay this weekend, the CR 450 R caliper needs to be anchored to the 99 ZRX swinging arm, I always like the way the Aussies and Brits describe the swing arm.

The coolest thing about blogging this stuff, is I get to thinking its been a couple weeks since I photographed and posted new accomplishments. Kind of motovates me.

I really do appreciate the comments. It's pretty hard to find another KZ enthusiast, aint the internet great!!

KawiConvert wrote:
On a side question, if I can lift up 250lbs with my arms and I weigh 125lbs, why can't I pick myself and a chair up into the air while sitting down? Do I need a chair with arms or a reclining back?[/quote]

you weight only 125lbs? well no wonder you think load on a tire really makes a difference, it does and your right. BUT also the reason for wider tires is not that the increased contact area automatically leads to more friction (though there may be some effects that depend on the area indirectly). The design parameter that determines the coefficient of friction between the tires and the track is the something related to the molecular compressibility of the rubber. In other words, "the softer the rubber, the better the friction." However, when you use a softer rubber, you need to make the tires wide enough to give them strength. So, "the softer the tire, the wider it needs to be", to withstand design forces and moments. The contact patch, or footprint, of the tire, is merely the area of the tread which is in contact with the road surface. This is the area which transmits forces between the tire and the road via friction. A tire rotating at higher speeds will tend to develop a larger diameter, due to centrifugal forces that force the tread rubber away from the axis of rotation. As the tire diameter grows the tire width decreases. This centrifugal growth can cause rubbing of the tire against the vehicle at high speeds. Motorcycle tires are often designed with reinforcements aimed at minimizing centrifugal growth. The length-to-width ratio of the contact patch will affect steering and cornering behavior. If tire pressure is too low, the tire contact patch is increased. This increases rolling resistance, tire flexing, and friction between the road and tire. The sidewall is that part of the tire that bridges between the tread and bead. The sidewall is reinforced with rubber and fabric plies that provide for strength and flexibility. The sidewall transmits the torque applied by the drive axle to the tread in order to create traction. The sidewall, in conjunction with the air inflation, also supports the load of the vehicle. Sidewalls are molded with manufacturer-specific detail, government mandated warning labels, and other consumer information, and sometimes decorative ornamentation. SO, in conjunction with air pressure to side wall flex, wider tires to strength and load pressure on tire to grip, all 3 laws need to be in balance for the best "GO" when racing. I'm not trying to argue I just have been racing for about 10 years now and from my own research this is what I know.


But yes your bike is looking awesome. can't wait to see her all done. you'll have a great deal of fun once she is up and going. best of luck to you.

badboie wrote:

load on a tire really makes a difference, it does and your right. BUT also the reason for wider tires is not that the increased contact area automatically leads to more friction (though there may be some effects that depend on the area indirectly). The design parameter that determines the coefficient of friction between the tires and the track is the something related to the molecular compressibility of the rubber. In other words, "the softer the rubber, the better the friction." However, when you use a softer rubber, you need to make the tires wide enough to give them strength. So, "the softer the tire, the wider it needs to be", to withstand design forces and moments. The contact patch, or footprint, of the tire, is merely the area of the tread which is in contact with the road surface. This is the area which transmits forces between the tire and the road via friction.

It took a while, but thank you for agreeing with me. Contact area doesn't effect traction. The stickiness of the tire effects traction. Contact area only decreases the stress on the tire. If you want we can take this to another thread and beat each other senseless with our keyboards.

So you both are saying that beings contact area doesn't affect traction, I can take a 500hp pro-street busa using a 190/55-17 M/T shootout tire and put a 90/90-18 tire in the same compund as the M/T shootout tire on the back of that same bike, and I will get the same traction? Call me stupid but I don't see it happening.

racer54 wrote:

So you both are saying that beings contact area doesn't affect traction, I can take a 500hp pro-street busa using a 190/55-17 M/T shootout tire and put a 90/90-18 tire in the same compund as the M/T shootout tire on the back of that same bike, and I will get the same traction? Call me stupid but I don't see it happening.

Your stupid, read 'em again.

contact area, load and the width of a tire all contribute to traction. there, its said and done. its over with now. bye bye

Nah! Not stupid...just see things as they are. All these explanations sound impressive but it's not that difficult. Some people just like to make things sound that way.

badboie wrote:

contact area, load and the width of a tire all contribute to traction. there, its said and done. its over with now. bye bye

No, Yes, No.

haha ok I just said that to make everyone happy,but I guess it didn't. here is a good read about friction and the laws applied. www.stevemunden.com/friction.html he explains it in the best way I can tell so far, better then all of us. so can we now call this conversation done? plus I never disagreed to the fact that load wasn't a factor, but if you have more area to put that load on then you are increasing friction, more weight can then be transferred. like in the article above he mentioned the box. the box will slide along the ground no matter how large or small it is if it has no weight in it. put weight in that box and it becomes harder to move. but if that box is small, less weight can be put in it say to a box that is large.