Jump to content
SAU Community

Recommended Posts

So when most 250cc bikes come with a 130 at their widest? Significant difference between that and a 190...

For a tyre to maintain traction it needs to run at a certain temperature, too cold = lack of traction, too hot = increased rate of break down with no increase of traction.

The rear tyre disperses heat under the power of the drive train so that it's temperature can remain in this 'sweet spot'. Larger bikes produce more heat and friction therefore needing a bigger tyre. Smaller bikes don't so they don't need a big tyre. This is why front tyres don't differ as much in size, because they are not under pressure from the drive train. You'll find the actual contact patch on the road is quite similar between different tyre sizes, providing the bike's set up correctly.

Putting a larger tyre on a small bike would just reduce the overall temperature of the rubber = less traction, stability of the bike, make it heavier and less aerodynamic. So if you're running out of grip it's probably going to be one of the other things I mentioned, not the size of the tyre :)

I'm talking about the wet...the thinner tyre is going to be better in adverse conditions for a new learner like Rimon. See motorcycle section in this wiki:

http://en.m.wikipedia.org/wiki/Aquaplaning

These advantages diminish on lighter motorcycles with naturally wide tires, like those in the supersport class.

Supersport is 600cc. Light bike, wide tyre. So this 'dimishing' is only specific to this kind, and probably not by much. You said 'the wider the tyre the worse it makes you in the wet' but it's more about matching the weight to the width of the tyre, like the Wikipedia article states.

Most likely the bike won't be the thing to make the major difference in this situation. Learn to control a rear wheel slide and that may save you.

Edited by JEPPE

This guy explains it better than me:

http://indianmotosblog.com/aquaplaning

Case in point, Rimon thought that bigger tyres on a bigger bike would be safer to ride with, not always the case.

Congrats Rimon. One day or two? www.bikesales.com.au :thumbsup:

lol... I read the first line. 'Monsoon time in India'. I don't think we'll be getting those conditions here.

Motorcycle Weight: Lighter motorcycles are likely to hydroplane more than heavy motorcycles. More weight causes the tires to stay in contact with the road and clear out water more easily.

Like the wikipedia article said, 600cc bikes are more likely to plane because they are lighter plus they have wider tyres.

So you should be encouraging him to not buy a 600. Only a 1000 or 250/125.

This guy explains it better than me:

http://indianmotosblog.com/aquaplaning

Case in point, Rimon thought that bigger tyres on a bigger bike would be safer to ride with, not always the case.

Congrats Rimon. One day or two? www.bikesales.com.au :thumbsup:

thanks was a 1 day course. money first then bikesales lol

Guest
This topic is now closed to further replies.



  • Similar Content

  • Latest Posts

    • Take the value it measured as, and pick the closest range available that is above the reading on the screen.   Also, no point just testing the coils. Read what has been said again. You need to test all your wiring, everything.
    • Does the scanner do all the CUs in the car, or only the ECU?
    • @666DAN sorry to bring you and old thread.     I've got my de+t done and it's all running great other than 1 small issue.    Car has remained auto with the na auto and tcm, I've used a stagea ecu with. NIstune board and everything is great other than my gear selection on the dash. It illuminates park, reverse, neutral, 3rd and 2nd when selected . But nothing when in  drive or what gear your in when you pop it into tiptronic. I'm sure there is maybe 1 wire in the ecu plug I need to move to rectify this. Do ya have any ideas?     Cheers man
    • Well I recently changed my rear axles and was thinking if I bumped anything, I have been driving the car for a while now though... But it has been raining today so everything is wet under the wheel arches. Brakes feel fine and can't hear any of the metal screamers, I had a squeak coming from one of the handbrake drums but that seems to have gone away a while ago. I was going down a hill when it lit up and I did feel the abs bite for a second and question why it did it?
    • Correct. Um. I dunno. I haven't cared enough about the way that the NA cars work to know for sure. But..... The 33/34 turbo manual cars have an electronic speed sensor in the gearbox that outputs a +/- (ie, sawtooth AC) voltage signal. That is connected to the speedo. The speedo then outputs a 0-5v square wave (ie, PWM) signal that the ECU (and any other CU on the bus) sees. The speed sensor is NOT directly connected to the ECU. So here's the problem. Your new ECU expects to see the PWM signal, but must somehow be getting a direct signal from the diff speed sensor. Which would suggest that the wiring of the NA car is not the same as the turbo cars. I think you will need to spend some time with (hopefully the wiring diagram for the car) and a multimeter to see what is connected to what. Then, presuming I am correct**, you would then want to separate the ECU speed signal input from the rest of the car's wiring, and probably either buy a speed signal converter, or build one using an arduino (or similar). That would take in the speed sensor signal and output a scaled (and suitably rearranged) signal for the ECU. ** We shouldn't presume that I am correct here, because there might be something else crazy going on. I don't think you could convert the speedo to be fed from the gearbox sensor, because the pulse rate from that sensor is probably different to the diff sensor and then the speedo would read wrongly. And this also wouldn't fix the ECU's problem either, because the ECU doesn't want to see the gearbox signal direct either (assuming that they are all on the same wiring, for some odd NA related reason, see above caveat!) Does this help? Probably not. Can you make it work? Almost certainly. With the above work. You should buy a handheld oscilloscope from Aliexpress so that you can view these signals directly. Connect up the probes and drive the car. Show photos of the screen when drving at known speeds and connected to different places, and we'll see what we can learn about it.
×
×
  • Create New...