Under Pressure! Talkin about Tires!
Welcome to this week’s tech talk at Venom Motor Sports!
Gotta love spring! Time to start getting our bikes ready for this years riding season. As we prepare our bikes an important consideration for us is our tires.
Think for a moment about the contact area between your tire and the road. Somewhere around a contact surface area of 10 square inches or less. This contact area is a very tiny space that is responsible for how your bike handles and stops. So we want to ensure that we take every precaution to ensure that we are using that tiny space well for maximum friction and contact with the road.
Spring is a great time of year to have a really good look at your tires and give them a critical inspection and cleaning! In this week’s blog we are going to address some common questions and concerns about tires and tire care.
To help with your understanding of “bike tires” please click on the various “tire” video links below. These will help you understand the different types of tires and tire maintenance guidelines.
Again a big Thank You! to my fellow “youtube” posters!
Keep in mind that this information applies to all of our bikes that have tires! Uhmm your right that would be all of them LOL.
If you’re not too tired...get it? let’s get right to the topic!
Tim...How is tire pressure measured?
Usually we use a pressure gauge placed on the schrader valve to take a pressure reading.
Pressure = Force/area so the units used are pounds/square inch or Newton/square meter
In the metric system One Newton/square meter is referred to as a Pascal.
Another common unit is the “atm”. One atm or atmosphere is equal to atmospheric pressure. Atmospheric pressure is the pressure that our atmosphere exerts on all things...all the time. We have an atmospheric vent on our fuel tanks to allow atmospheric pressure to act on our fuel and help move it through our fuel system. If the vent becomes plugged your bike will run fine one moment and “bog” down the next from a lack of fuel flow.
Atmospheric pressure = 14.7 psi or 101.3 kpa.
So if the pressure rating on your tire is say “2 atm” cold, then the pressure would be 2 x 14.7 psi = 29.4 psi.
The cold....means that we should always fill our tires when cold first thing in the morning, before our first ride. This is dues to the fact that as the tire gets warmed up while riding the pressure inside the tire increases. Manufacturers allow for this when choosing the best cold temperature to fill your tire too. Typically tire pressure will increase inside the tire up to 3 psi when warmed.
Tim...When my ATV arrived there was very little air in the tires, is there a reason for this?
Yes! the reason is very simple, under inflated tires take up less space in shipping.
Your ATV tires typically require around 12 psi under normal operation. It is a wise practise to over inflate the tires slightly say to 20 psi...then bleed the pressure back off to 12 psi. This is done to ensure that the tire bead seats properly with the tire rims.
It is very important to fill the tires before trying to ride the atv. Our electric ATVs feature tires with tubes. If you drive the electric ATV before the tubes are properly inflated you will damage the Schrader valve and will have to replace the tube inside the tire.
Tim...How can I tell when my tire needs to be replaced?
Because it’s flat? LOL, That would be a good replacement situation…too funny.
Let’s run down a quick list of times when motorcycle tires should be replaced:
- Sidewall puncture
- Damage that can't be repaired
- Tire with a puncture larger than 0.25 inches
- Tire more than 10 years old
- Weather-checked (cracked around the circumference), often due to UV or fluorescent exposure
- Tire that has been run with exceedingly low pressure (damage is typically seen as a circumferential ring that looks “rubbed in”)
- Tire with cuts or slices
- Tire with missing tread blocks
- Tire that is worn (less than 2/32 of an inch of tread in any area)
- Tire displaying treadwear indicators
- Tire that has cross section significantly altered (flatter or more pointed due to uneven wear)
- Tire that is feathered or cupped and is making noise or exhibiting a choppy ride; some front tire cupping is normal, but a worn tire may exhibit severe feathering.
If you’re asking us this question, you probably need at least one new tire, and likely two. Given that most bikes have a tire speed rating, and repaired tires lose their speed rating, most people with any type of tire damage need a new tire.
Too learn more and see the full article where the above information was sourced click on the link below,
https://www.revzilla.com/common-tread/motorcycle-tires-101-guide
Tim...What do the terms Tread, Bead, Carcass and Sidewall mean as they relate to my tires?
- Tread:This is the part you see that hits the road, and the part most people think about. In general, smoother tread works better on smooth, dry surfaces, and “chunkier” tires work better off-road. Some street tread patterns are designed to do better in the wet and off-road tires come in a wide variety for different surfaces, from hard-packed dirt to sand.
- Bead:This is the part of the tire that mates to the wheel. It is typically steel wire covered heavily in rubber. The bead has a snug fit to the wheel to prevent the wheel from slipping rotationally in the tire.
- Carcass:In simple terms, this is the “body” of the tire under the tread. Motorcycle tires are typically bias-ply or radial, which refers to how the tire is constructed. Radial tires have reinforcing belts (which are almost always steel) running from bead to bead across the tread of the tire. Bias-ply tires have belts which are typically cords made of fiber, such as polyester, aramid, or fiberglass, that run from bead to bead at an angle of 30 to 40 degrees or so. (That’s the bias!)
- Sidewall:The area of the tire that bridges the tread and bead. A small part of the tire, it is vitally important. It gives the tire much of its handling and load transfer characteristics. This is the part of the tire we’re talking about when we reference height, profile, or aspect ratio. Typically, a shorter sidewall yields a stiffer sidewall, which tends to flex less. To a rider, this means better handling and turning, worse bump absorption, and more difficult mounting. This section greatly contributes to the tire’s role in the suspension. That’s right — the tire is a suspension component!
Too learn more and see the full article where the above information was sourced click on the link below,
https://www.revzilla.com/common-tread/motorcycle-tires-101-guide
Tim...How are my tires sized?
Metric Measuring System is used on all our bikes.
The most common of the tire size designations, known as the metric measurement, begins with the section width. The table below contains the five parts of a metric tire number.
Designation |
Order |
Definition |
|
Section Width |
First |
The tires width in millimeters, measured in a straight line from one edge of the tire's tread to the other edge |
|
Aspect Ratio |
Second |
The ratio between the tire's width and its height; the higher the aspect ratio, the taller the tire will be |
|
Rim Diameter |
Third |
Measured in inches, the measurement from the inside lip of the rim on one side to the inside lip of the rim on the other side |
|
Load Rating |
Fourth |
Each tire type is specified with a specific load rating; the higher the number, the more weight the tire can safely bear |
|
Speed Rating |
Fifth |
The speed rating indicates the maximum speed for that specific tire |
When buying tires, make sure that the tire size fits the rim. Otherwise, the tire can have a blowout, as tire too large for a rim will not create a seal with the rim.
Too learn more and see the full article where the above information was sourced click on the link below,
https://www.ebay.com/gds/How-to-Read-Motorcycle-Tire-Sizes-/10000000177633477/g.html
Tim...What do all those numbers on my tire mean?
The codes vary, of course, from tire to tire but for the most part are universal across brands:
- M403 (model #)
- 80/100-21 (tire width/aspect ratio - rim diameter)
- 51M (Load and Speed Rating, 51 = tire load rating, M = tire speed rating)
- 2912 - This tire was manufactured the 29th week of 2012
Tim...My tire has an “H” on it, is that important? A friend told me it has an “H” for “HOT”!
The “H” is an indication of the maximum design speed that a tire can handle. Have a look at this chart.
Tire Speed Rating
Motorcycle tires are rated for a certain speed when they are designed. This is the maximum speed they should be driven at while on the road. Driving faster than the maximum rated speed can lead to tire failure, bike damage, and possible injury or death. The following chart gives motorcycle tire speed ratings.
Tire Speed Ratings |
Max. Design Speeds |
Test Speed |
|
J Type |
62 |
100 |
|
N Type |
87 |
140 |
|
P Type |
94 |
150 |
|
S Type |
112 |
180 |
|
H Type |
130 |
210 |
|
V Type |
149 |
240 |
|
Z Type |
149+ |
240+ |
The above speeds signify tires at the proper air pressure and in optimum riding conditions. Riders should take care when traveling in adverse conditions. Also, observe all posted speed limits when riding a motorcycle.
Too learn more and see the full article where the above information was sourced click on the link below,
https://www.ebay.com/gds/How-to-Read-Motorcycle-Tire-Sizes-/10000000177633477/g.html
Tim...Have you found any good video’s on “tires” for our bikes?
Yes! gotta love “youtube”, thank you fellow youtubers for sharing your videos.
The video’s listed below are some of my favorites. Just click on the link below!
Motorcycle Tire Pressure and Why It’s Important! | MC GARAGE
https://www.youtube.com/watch?v=S371SeT-b4M
What Tyre Pressure Settings Should I Run On My Motorbike
https://www.youtube.com/watch?v=y20M_yxSV3k
Streetbike Tire Categories Explained | MC GARAGE
https://www.youtube.com/watch?v=x5CFUEHF2-M
How To Tell If Your Tires Are Toast | MC GARAGE
Check out our blog next week as we look bike suspension systems.
If you have any tech questions about our bikes, please feel free to email them to...
Have a great day!
Tim
Technical Support Specialist
Venom Motor Sports Canada
1-855-984-1612 hit “2” for “Tim”
