April 09, 2021

Why Grooves Matter in Tyres?

Why You Should Be Paying Attention to the Groove!

We’ve talked about r-compounds, we’ve talked about treadwear, and we’ve talked about the 651 Sport as a whole.  So, what’s next?

A lot of you have questions about the overall wet performance of the Accelera 651 Sport. If you have ever used r-compound tyre, you will find they don’t always perform well (or at all) in wet conditions. This is mostly due to their tread pattern.  Yes, almost every directional tyre boasts a v-grooved design that is made specifically for wet conditions.  But that is not always the case.

Before we dive into how these key features work with 651 Sport, there are a few of things that need to be defined.

So what is the tread pattern?

For starters, tread pattern is the contact patch of the tyre.  More specifically, the rubber that is in the circumference of the tyre, consisting of groves, blocks, and snips. These little parts allow you to grip in places or not, brake harder, and have a direct impact on your overall handling.   One of the most overlooked reasons for tread pattern in r-compounds is for water evacuation. Most semi-slick tyres are designed with a ‘less is more’ mentality.  In order to keep the overall performance of the tyre, companies design these specific group of tyres with groove tread patterns in mind.  This is because grooves are the reason for better-wet handling. R-compounds are designed this way to give the tyre a slick or semi-slick feel, allowing the tyre to have a lower tread rating and ultimately raising the overall performance of the tyre in every condition you run it in.

The Grooves Explained: Tyre grooves are a major part of the tread pattern moulded across or around the tyre.  They contribute to the tyre’s void ratio (groove area vs. contact area) to aid wet traction and increase the number of biting edges that enhance acceleration and braking traction on loose surfaces. Additionally, grooves also contribute to wet traction by permitting water to flow directly through the tread design, having the greatest influence on the tyre’s hydroplaning resistance.

There are three different types of grooves.

Circumferential Grooves:
Circumferential Grooves are major grooves moulded around the tyre. These grooves also provide lateral biting edges that enhance cornering traction on loose surfaces. Circumferential grooves are the deepest grooves moulded in a tread pattern and remain visible throughout the tyre’s life. This is also where you will read the tyre’s tread depths.

Lateral Grooves:
Lateral grooves intersect their adjacent outboard and inboard circumferential grooves and result in the formation of independent tread blocks. A lateral groove that reaches only one circumferential groove (or the tyre’s shoulder) is referred to as a lateral notch.

To provide more stability and handling, lateral grooves often feature less tread depth (often about 2/32” less) than their adjacent circumferential grooves. This results in lateral grooves visually disappearing completely as the tyre wear approaches 2/32” of remaining tread depth.

Tie Bars: 

Tie bars are short rubber links moulded across lateral grooves between adjacent tread blocks. Often used between independent shoulder tread blocks, tie bars connect tread elements circumferentially to reduce tread squirm when rolling, as well as during acceleration and braking. By opposing block movement, tie bars promote stability that help resist irregular wear. However, as the tie bar wears, the portion of the lateral groove will disappear and reduce into a lateral notch, sacrificing overall tyre performance.
(info from http://www.tireprofiles.com/tread-pattern-anatomy/)

How does all this apply to r-compound tyres?

Stay with us here.
Most “track” tyres are designed with grooves to aid in handling and overall high-speed performance. A lot of other r-compounds claim to be capable of handling wet driving, but that is not the case.  A further dive into the treadwear would show they are missing the key elements that are required to be effective in wet driving.  Most r-compounds are made semi-slick in order to achieve overall track performance in the hottest conditions but end up lacking wet driving proficiency.  This is because some r-compound or race tyres only include one groove with multiple tyre bars (like the tyre pictured).  This is done to keep the treadwear at 180 or below, thus providing exceptional dry grip during hot dry race days.

So how does the Accelera 651 Sport compare to the rest?

The overall design of the Accelera 651 Sport has a pattern that is almost exclusively a groove design. A combination of circumferential, lateral grooves, and connecting tyre bars across the entire surface of the tyre aid in exceptional water disposal in wet conditions.

In turn, these grooves will prevent aquaplaning/ hydroplaning in standing water, all without sacrificing overall tyre performance.  This design is also equipped with deep dimple grooves that work to break the water film layer on the surface, while also cooling the tread surface during dry conditions. Because of this, the Accelera 651 Sport features a three-groove design which provides grip in any condition you drive it in.

So, the next time you wonder what those grooves are and why they matter, just remember. more grooves mean better handling any condition you drive in.  

Check out this testimonial from our guy Rafael on how the Accelera 651 Sport handles in wet conditions: 

"First set of semi-slick tyres that I have used that provide excellent grip even in rain!! Compared to R888 which feel like your car is ice with even the slightest wet pavement. I recommend these to anyone looking for an economical alternative to Toyo and Nitro. They excel: on and off the track, time attack, autocross, or even drift. They have maximum grip for every event type. Thread life is more than adequate for weekend fun!!"