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Large trucks large tires.

PostPosted: Tue Sep 01, 2015 10:08 am
by Bryce D
So I have tires on the old truck they are 9-20 whatever that means. I know that they are many years old. They look ok. How does one tell that they are or are not ok?

Re: Large trucks large tires.

PostPosted: Tue Sep 01, 2015 12:30 pm
by cornbinder89
One way is the date code in the DOT code on the sidewall. Bias ply tires will age better then radials. Old rubber will "chunk out" when they hit an obstruction where a newer tire will flex and roll over it.
Whether to replace or not is up to you, look at the sidewalls for cracking etc. I've run some fairly old bias tires and not had a problem, but as I say, the 1st chuck hole you hit will likely take the tread right down to the plys.
My tire place will not re-cap a radial caseing over 6-7 year old, they claim the base rubber will separate.

Re: Large trucks large tires.

PostPosted: Tue Jun 14, 2016 8:10 am
by ijimcarey
{Bryce}--TIRES & WHEELS--your 900X20--means your wheels are 9 inches [WIDE!} & the RIM is 20 inches in DIA--hope? this Helps!--

Re: Large trucks large tires.

PostPosted: Tue Jun 14, 2016 9:30 am
by cornbinder89
ijimcarey wrote:{Bryce}--TIRES & WHEELS--your 900X20--means your wheels are 9 inches [WIDE!} & the RIM is 20 inches in DIA--hope? this Helps!--

Not exactly. the 9 is aprox width of the tire at its tread. The rim width is much narrower. A 9.00 would be designed to fit on a 7" rim width. It may be fitted to 7.50" or 6.50" rim.

Re: Large trucks large tires.

PostPosted: Thu Jun 16, 2016 1:15 am
by ijimcarey
CORNBINDER--I have several 9X20 wheels w/ tires mounted--I rolled one out--& measured it--Firestone--9 inches WIDE!--20 inch RIM--Dono? rim Width?--I have 10.00 20 inch Tubless rims-NO small ones!--Not Mounted!--& All the Metrics are different--the New Western Star has Floations on Front--really Wide!--jim--

Re: Large trucks large tires.

PostPosted: Thu Jun 16, 2016 9:12 am
by cornbinder89
10.00 X 20 fits on a 7.5 or 8" rim. It has an aprox tread width of 10.8". The numerical numbering doesn't equal the rim size. You can look up the spec's on a tire mfg website.
Rims are measured from inside width between the rim flanges.
The only 20" tire that can be mounted on a special tubeless rim is a military rim with a O ring. the rim bolts together. the tire can be used with a tube on conventional 2 or 3 piece rims or without a tube in the special military bolt together rim. To use without a tube it must be a tire that was built for tubeless service (with an inner liner molded into the tire). The tire will be marked as tubeless, or will say it can be used with or without a tube. Most 20" tires are tube type and must be used with a tube, as they lack an inner liner.
in general, 20, 22, and 24" tires are tube type, 22.5, 24.5 are tubeless.