Need help translating chinese tire sizing into Pirelli SL26 By olivertwisted (Read 1,280 times)

[olivertwisted]

Maybe, I spoke before I should have! So, looking at the calculations that rks put up "110x100x12" , the 100 refers to diameter? You guys must be exasperated by me. I think I conceptualize visually so, I have a hard time bringing it all together in my mind.

[olivertwisted]

On the lighter side .. I spent the last couple of days wire brushing, naval jelly-ing , painting and curing VHT onto that rusted old exhaust. Alley was right , by the time I'm done, I'll know every inch of this scoot. With all of this help, I will have learned a ton!




The burn guard, I'll do in white to match the body panels

[rks]

Dec 14, 2015 2:32:25 GMT -6 olivertwisted said:

Maybe, I spoke before I should have! So, looking at the calculations that rks put up "110x100x12" , the 100 refers to diameter? You guys must be exasperated by me. I think I conceptualize visually so, I have a hard time bringing it all together in my mind.

A tire stamped 110x100x12, is 110 milimeters wide......the side wall is 100% as high as the tire width....and the wheel is 12 inches in diameter.   The middle number is always the sidewall measurement, expressed as a percentage of the tire width.

In the chart I posted earlier, the diameter of each tire size is listed in inches, followed by the letter "T"

Now, multiply the diameter by 3.14 to get the circumference, in inches, (the distance the tire will travel in one revolution)

Divide 63,360 (the number of inches in a mile), by the tire's circumference, and you'll have the revolutions per mile for that tire.

So, a 4.00x12, with a diameter of 20.5" will travel 64.37" in one revolution, or turn 984.3 revolutions in a mile.
A 120x70x12, with a diameter of 18.6" will travel 58.40" in one revolution, or turn 1084.9 revoltions in a mile.

That is a big difference.....so pick wisely

[richardv]

I don't think we are exasperated. But, you sure have our little brains working.

[johnjs]

Omg im confused and i am not even buying tires yet uggggggh

[Alleyoop]

Here is a calculator for tire comparisons.
Just plug in the old and new values and get the poop.
Alleyoop

www.csgnetwork.com/tireinfo4calc.html

Here are the speed ratings:

Tire Speed Rating Chart:

Max. Design Speed (MPH)
J.......62
K.......68
L.......75
M.......81
P.......93
Q.......99
R.......106
S.......112
T.......118
U.......124
H.......130
V.......149
W.......168
Y.......186

[olivertwisted]

Oh my gosh! Thank you so much rks , If I can't get that, I'm brain dead ! I know , it took some time to type that out so,thank you, thank you!

That is an awesome tool you linked to Alleyoop , thank you! I hadn't come across one like that, at all.

Nothin' like a a good ol' cerebral workout, eh richardv ?!

Lol, johnjs , you may wake up tomorrow to find that you've purchased tires, in your sleep!

[olivertwisted]

After a few discussions with Motorcycle superstore here's their take ; They wanted me to stay with a 110/90/12 but found that they didn't have both a front AND rear tire within a certain brand and make to achieve that, other than in Shinko tires. For better quality, they agreed that I should go with the SL26's but came to the conclusion that I may run into a clearance issue with a 130 for the rear. So they suggest the 120/70/12s in the Pirelli SL26's for both.

How does that sound ? What would you all say that I would experience with those, as regards RPM and top speed, etc?

[Alleyoop]

The ones that were on there are just a little taller is why you MAY and MAY NOT see just a little difference in speed is all. We are not talking a heck of a lot just a little that you may not even notice. Like I mentioned in the beginning most slap on 120/70/12s in front and and 130/70/12s in the rear.
Alleyoop

[olivertwisted]

Gotcha , thanks Alleyoop And yes, I definitely have referred back to your suggestion and this thread for guidance and it has been a huge help .I hope ya know that my reaching out for final assurance is for a lack of confidence in my own assimilation of all the info that has been offered up, not at all in the fine peeps here or, the info itself

[Alleyoop]

Yes, i am aware of why people reach out as well as others with their problems and or questions. I always tell people do not hesitate to ask for help and or question something. That is how we all learn by asking and doing things.
Alleyoop

[olivertwisted]

[rks]

If you reduce the distance a tire travels per revolution by 9 or 10%, (as you will be replacing a 4.00 x 12, with a 120/70 x 12), it only makes sense that you will have to spin it 9 or 10% faster, to cover the same amount of ground, in the same amount of time. That can be quite a difference in rpm's by the time you get to your normal road speed.

Of course, this could be compensated for, by going to heavier weights in the variator.

[olivertwisted]

Thanks, rks Since I can't quite grasp this one overall, I am thinking to stay with the safest option as far as fit goes and to stay with the ones that your table points out as closest in size to what is already on there, the 110/100/12s, or the 110/90/12s (110/90/12 Not available in the SL26s that I see, though). The other dimensions may offer benefits or disadvantages, but what I am most worried about is ending up with some clearance issue that is only discovered after mounting the tires and then not being able to return them. So far, I've found several things on this scooter that are not in common with other 150s, and references are few. My luck isn't usually too great so, I'm thinking the safest option is probably wisest for me

 I already purchased slightly lighter sliders( 18x14x12) than the rollers that were in there so, I don't want to go too backward here, lol!