Modern equlivalents to older tyre sizes.

**Warthog** · #1 26 May 2008

My Ural runs 4.00 x 19 tubed tyres on all its wheels. 4.00 x 19 has a fairly limited choice of tyres avaialbe. I have found one with lots of potential: the Heidenau K37.

However, is there a rule of thumb conversion to see if more mmodern tyre sizes can be fitted to my rims? There are so many more tyres avaialbe to me that way.....

**Frank Warner** · #2 27 May 2008

Quote:

Originally Posted by Warthog

However, is there a rule of thumb conversion to see if more mmodern tyre sizes can be fitted to my rims?

4 inches = 100 mm

So probably a 120/130 will fit ... it depends on the size of the rim and how much clearence your bike has ...

When you select the tyre make certain about the 'tyre load rating' .. no point in puting on a tyre that won't handle teh weight see Motor Cycle Tyre Codes

**Warthog** · #3 27 May 2008

Quote:

Originally Posted by Frank Warner

4 inches = 100 mm

So probably a 120/130 will fit ... it depends on the size of the rim and how much clearence your bike has ...

When you select the tyre make certain about the 'tyre load rating' .. no point in puting on a tyre that won't handle teh weight see Motor Cycle Tyre Codes

Thanks for that. Based on that I searched a little more and found that 110/90-19 and 120/80-19 tyres should fit.

I just need to check my mudguard/swingarm clearance to be sure...

Still do not know about the weight rating aspect so any pointers here are appreciated...

**oldbmw** · #4 27 May 2008

You might want to check out 'chen shung' tyres. They do teh whole range of old sizes in newer compunds. Enfiled dealers will hav 19" by 3.25 and 3.50 sizes, presumably they could tell you where to get the 4" Strictly speaking a 4" is a metric 100x100 Ie 4" diametre by 100% radius.

**Frank Warner** · #5 28 May 2008

Even your 'old' tyres will (should) have a load and speed rating .. a letter an two numbers .. on teh side wall after the tyre size ... see the link I gave above to interperate these ... You'd want a similar load and speed rating on replacement tyres.

Arrr knew I had it somewheres - tyre to rim sizes .. says how small/big a tyre you can mount to a certain rim size - rim size is from bead seat to bead seat (inside) dimension .. rims sizes are in inches still.
Motor Cycle Tyre Codes