Tires do not shrink but the material of the tire becomes hard and stiff if you have not touched the tire for years if you touch it to feel the material it should be quite hard by now or even deteriorate with a little bit of force.
the tire bead becomes so stiff that even by using bead-breaking tools you would not be able to hook the tool because of the inner rubber material of the tire. thick tires become much harder if they have been placed for a long time with no usage. this stiffness increases over time and the rubber loses its flexibility and softness due to the weather and moisture in the atmosphere and other factors.
Can you use an old shrunk bike tire for riding?
Yes, you can further use it for riding purposes but as it’s an old tire, its working performance is decreased as compared to a new tire and you have to avoid high-speed racing, aggressive and rough terrains, and long-time ridings. because it may have become loose or stretched due to long-term storage but mostly the tire rubber is so hard and stiff that it would not tolerate aggressive rides.
What Causes Bike Tire To Shrink Over Time?
Cold water and snow cause the bike tire to shrink, riding regularly on trails with 2 to 3 feet of snow or riding through wet cold trails with temperatures lower than -20 degrees. this cold condition will constantly shrink the rubber and foam of the tire together which causes the tire to shrink.
the other big factor is long-term storage, for example, if you left your bike standing for years (1,2,3)depending on the material the tires are usually unrideable any more, on a shorter note a tire will deflate in a month and maintain a pressure of around 6-10 psi for the next remainder month or so and then fully deflate to an extent that
no air is left in it and at that point, it just starts getting worse and the environmental factors and the added weight on the tires accelerates their deformation.
Seasonal tires also shrink there are specific tires for summer seasons and when winter comes they need to be unmounted and stored but the bottom line is no matter the rubber it will deform and deteriorate over time.
How to check a Shrinked tire?
the best way to check the tires to see if they have shrunk or not is to check the material of the tire to check that simply inflate the tire at low pressure in case of mtb inflate the tires to 20-30 psi and in case of a road bike or other tires you can inflate them with the normal pressure as well and press the tires with finders check the hardness of the bead and see how flexible they are that will give you a clear indication of how much the tire has shrunk.
Now fully inflate the tire with high psi pressure of 60 to 70 psi, and bring your bike on jumpy and bumpy trails, go for a ride and whip your bike in the air so that the tire would hit the ground repeat the whip and jumps and notice if the tire is hitting hard on the surface like the normal tires then it is good condition but if the tire is not making any noise of hitting then it is in bad condition.
Does Sun and Heat Cause normal Tire To Shrink?
Hot and warm weather does not cause tire4sw to shrink in warm conditions, if the tire is in cold weather for a long time then the normal tire starts to shrink, and as a result, the normal tire becomes useless.
How To Avoid Tire Shrinkage Over Time?
Tires need proper caring on daily basis. When tires are in running mode, wet the tire beads during mounting and unmounting of the tire in the rim with soapy water, spray and lube. when you leave the tire over time without using it, this wetness of the bead does not allow the rubber and casing of the tire to become dry over time.
Inspect the sidewalls and beads of the tire after every ride, you will notice if the rubber and casing of the tire are going hard and increasing its stiffness then with the help of a bead breaker, hook the tool within the bead and repeat the same process on 4 to 5 places on both sides of the bead, this process prevents tire shrinking over time.
There is also another hand method of breaking the bead, the main purpose is to break the tire bead in the beginning after that the shrunk tire will unmount from the tire.
If the old tire is still hard and stiff and it is not mounting from the rim, then stand your bike on the floor under the light of the sun to hit the tire bead and sidewalls which makes them soft and flexible to break the bead.
After unmounting the shrink tire, it is hard and stiff, you have to warm the tire by giving heat of sunlight and warm water to increase the activity of the rubber of the tire for further rides.
Size Of Tire Shrink Over Time?
Its size decreases from 3mm to 5mm short if the tire remained useless for more than 2 years mounting on the tire rim, the sidewalls will not pop out when the tire is aged and you have to limit the rides on old shrink tires.
Sometimes the tire is of smaller width from the rim, when you mount the new tire it will easily install but when you got a puncture on the same tire or if you want to change the rim tape, you need to unmount the tire from the rim, now at this time small width and small sized tire will cause much difficulty in unmounting, the reason is that, it is now hard and stiff because it is the rule of rubber material, you will buy 1mm large width tire and after riding for 5 to 6 months the tire will shrink from 1mm to 2mm and become undersized.
There are different kinds of rubbers and materials with different characteristics and properties which are used in the manufacturing of tires, some kinds of rubber shrink early, and some rubbers shrink lately.
Sometimes the tire bead does not seat properly on the rim lip and it causes slipping and sliding, it happens because the width of the tire is changed due to weather and the tire loses its grip.
The material of the tire is responsible for shrinking :
7 to 8 years old tires have different rubber material which is cotton, foam, silk, and sponge, these materials do not last for a long time if their tires were used to run on wet water trails and snow, and tire bead shrinks after some years but modern and new bike tires have different rubber material which contains polyester and nylon, it is long-lasting and does not cause negative effect on the tire bead, this difference would cause the tire and its rubber material to shrink earlier.
If the tire is more than one year old then the rubber material of the tire starts becoming hard and stiffer, it depends on you how long you will pick the tire for usage. the rubber of the tire becomes so stiff you will not be able to unmount the tire from the rim after 18 months of no use, it usually happens with the old tires, which were in running condition when you were riding on the trails, If you followed more aggressive downhill and twisted trails with much more speed, then after passing few months you will notice rubber of your tire becomes stiff and hard but do not cause shrinking.
Tire Density over time:
The rubber material used in the tire casing are close together when the tires are new and fresh and in running mode, so the tire density is deep and the tire is enough thick to absorb the bumps and jumps arising from the both front and rear tires, but if tires are not in use and old density of tire continuously decreases over time which brings the difference in properties and characteristics between old and new tires.
New tires have soft rubber and are freshly manufactured, rubber particles are still active and wet but in old tires, the rubber, foam, and fiber are not fresh and dry over time which further decreases the density and capacity, and performance of the tire.
If the tire is in a running state on daily basis then after riding many thousand miles, the tires lose their weight due to the shrinking of the rubber material, it totally depends on the aggressive trails of your hometown and the weather, usually, 30% of riders body weight and the bike weight aligns on the front tire and 70% weight of the rider sits on the rear tire, it shows the rear tire is tolerating more weight as compared to the front tire, due to these differences front tires do not lose weight after 2 to 3 years but you will expect a noticeable difference in the weight of the rear tire after 3 years of constant running.