Retiring the tires

Hey its Rhyme… :), I changed the tire the other day as the tire is too old and bald… its long over due tire change I might say, because I can see small cracks in the rubber.  The question is: which tire… Actually not much choices if you use stock rim. In Indonesia the most use tire  for stock rim is  X-tra grip from GoodYear, a long lasting tire, ok light off-road, but road usage is not ideal.. here is the thread pattern of the tire:

goodyear xtragrip

Some tips when changing tire:

  • Ideally if you can change all four then change all of them… or 5 of them including the spare tire
  • If you can not change all of them  change two tires is minimum, never change only one unless absolute necessary…
  • Put the new tires at the front, because the front tire will get bigger force when you braking… if you put old tires at front, the braking will not be optimum
  • Do not use the tubeless tire on the stock rim, it designed for tubed tire… Some will say you can, but I suggest not…
  • The equivalent of  750×16 tire for tubeless is 235/85 R16

So off I go to tire shop and change it… since I am using the stock rim, I opt for 750×16 tubed Xtra Grip tire… cost me US$ 120 x 4  fiuh…

Changing tires
Changing tires

The easy way of changing the tires is ask to the seller, what is the best tire for your rim or equivalent of your current rim…

but If you are geek… read on.. :

Crash course on tire size : There are three ways giving the description of tire size, the source of confusion… here you go..

  • American way: Height/width X Rim Size => I.e : 31/10.5×16 means: 31 inch diameter, 10.5 inch width, for 16 inch rim
  • Metric : Height (mm) / Aspect Ratio side wall height  X rim size => I.e: 235/85X16 means: 235mm width, (235×85%=)200 mm side wall height for 16 rim.
  • Imperial: Width X Rims size => I.e: 7.5X16 means: 7.5 inch wide for 16 inch Rim imperial also means aspect ratio is 100% hence it equal to 7.50/100X16

I said earlier that the  235/85X16 (lets say tire A) is equivalent of 7.50X16 (lets say tire B)..? How come..? let me try to explain…

  1. To make it easy, lets convert all to inch..? let say 1 inch is 25.4 mm.
  2. Tire A: (235/25.4)/85 X16 = 9.25/85 X16  while tire B is  7.50/100X16
  3. From the above, we know that the Tire A: 9.25 inch wide, and Tire B : 7.50 inch wide
  4. So equivalent does not mean exactly the same, the Tire A will be about 1.75 inch wider.
  5. Now how about the overall diameter..? this is where the aspect ratio come into place
  6. The overall diameter formula is easy : (Side wall height X 2)+Rim size
  7. Tire A side wall height would be: 9.25×85% = 7.86 inch, while Tire B side wall height is: 7.50 X 100% = 7.50 inch
  8. Overall diameter Tire A would be (7.86×2)+16 = 31.7 inch,  while Tire B would be (7.50X2)+16 = 31 inch
  9. Hence: In terms of Diameter,  Tire A would be 31.73 inch and Tier B would be 31 inch so tire A would be a tad higher
  10. However when I compare it side by side.. the 7.50X16 Xtra Grip from Goodyear is a tad higher than Bridgestone 235/85X16

Confused…? mee too.. :D


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