Standard tyre size?

[AxlFoley]

Jus wondering what the standard tyre size is on a 14" rim, i want to go up to a 15" rim but need to make sure the rolling radius is the same as standard, as i cooked the engine in my beetle running 195x45x15s lol i didnt know much about geering at the time!

my van is running 205x70x14s at the moment, is this standard?

Thanks

Mark

 

[Pete B]

Mr Haynes says 185R14C. So thats a 'standard' 80 series tyre with commercial vehicle load capacity.
A good tyre centre should have info on tyre sizes, Michelin used to publish a 'bible' on tyre spec, but that was many years ago!

 

[froggy]

Stock size is 185/14 commercial which i think works out at 185/82/14's.
There was a wheel size calculator on 1 of the threads (cant rememer which one though) which you added the tyre size you wanted and it worked out how much difference this would make to the speedo

 

[uber cool]

clicl on the link below enter current tyre size and new tyre size, it will tell you the rolling radius and % difference.

Worth adding to your favorites :mrgreen:

http://www.miata.net/garage/tirecalc.html

 

[froggy]

Using the calculator, then 205/65/15's are about as close to stock you can get to keep the speedo accurate (ish) but whether they will fit under the arches are a different matter

 

[Pete B]

205/65x15 may well be the size with the same circumfrence as a 185/80X14 and give the same speedo reading. On a std height bus this may be fine, but when lowered that tyre is going to foul, slam it and you have no chance! Remember, the speedo is driven by the n/s/f wheel, usually the one with the smallest diameter tyres so speedo reads very optimistic!
Worth thinking about if you have a milleage limit on the insurance. For me that difference relates to about 1,000 miles more on the odometer than I have done over the year.

 

[AxlFoley]

seems my current setup is undersized by 11mm, that could explain the spedo being so far out!

 

[Tofufi]

as i cooked the engine in my beetle running 195x45x15s lol i didnt know much about geering at the time!

That's quite a lot smaller rolling radius than a stock beetle tyre!

Must have been good acceleration but poor top speed?

 

[AxlFoley]

yeah it was damn quick! but i drove it home from work one day in a rush at full speed, and cracked both heads! not good