RIM SIZE = TYRE SIZE

so i got a inspection on my bike today and of course it passed,
however the tyres are border line so i need front and rear tyres,

im not asking for Tyre recommendations just help determining the max
size the rims will take,

i have loads of clearance so width isn't the issue but just becouse i can get a 180 rear between my swing arm doesn't mean the Tyre won't misshapen because the rim isn't wide enough for the Tyre,

i currently have dymag 18''s on the front and rear running 110-80-18 and 160-60-18.

the front end could take a wider Tyre as could the rear however this may distort the sidewall of the Tyre.

so is there a magic math sum that determines a 3.25'' wide rim can only take tyres between 100 -120 and a 4.75 can take 120 - 140?

if so where do i measure rim width?

you measure rim width from inside of the bead to the inside of the other bead. with a 4.75 rim you should be able to use a 160 tire now the tough thing will be to get an 18 in that width

This may or may not help, but if you go to the link below you'll find the Dunlop Tire Fitment Guide. Try different model bikes and you'll see that for many of them it gives the front and rear rim width along with the recommended tire sizes. This may help you figure out the relationship between rim width and tire size. Ed

Fitment Guide

acording to his i have too big tires on my rims :S

That chart doesn't show the rim sizes. It only shows the metric/alpha/inch conversion for each tire size. Take a lookk at the fitment chart in the link to see the rim size/ tire size relationships. Ed

kano wrote:

so is there a magic math sum that determines a 3.25'' wide rim can only take tyres between 100 -120 and a 4.75 can take 120 - 140?

if so where do i measure rim width?

On mine, stock is 3.25-19 front and closest metric equivalent is 100-90-19. 110-90-19 is definitely too big for my front.

My stock back was 4.00-18 and 110-90-18 is closest equivalent (about the same width, a shade less diameter). I believe 120-90-18 would be close to a 4.75 tire equivalent.

so i rechecked my dymag rims and i am running.
its kinda hard to measure and to be honest my rim size measurements are probabley under true size.

rim size 3.25-3.50 on the front current tire 110/80-18
rim size 4.00-4.50 on the rear current tire 160/60-18

however the rear tire sidewall is defiantly distorted
probably becouse i put the 160 on it!
front tire looks good though?


so i ordered
110/90-18 FRONT - THE BRIDGESTONE SPITFIRE S11F
130/90-18 REAR - THE BRIDGESTONE SPITFIRE S11R

Don't know about Dymag, but stock wheels have the width cast into them.

unfortunately these dymags don't just my luck.