12 Jan, 2017

The Great Rubber Debate


“What tyres should I put on to my bike? I want a tyre that rolls fast, has excellent grip in mud and sand, and is light and puncture-resistant. What have you got like that?” At some point all riders ask their local bike shop this set of questions. – BY THE GENTLEMAN RACER

In reality, any tyre can only fulfil two or three of the above, as there are many conflicting goals in that request. A tyre that has low rolling resistance, crucial for those long winding district roads, will always struggle to find grip on a loose, muddy surface. The large, spread-out knobs of a grippy, loose-condition tyre will never roll fast. And a light tyre casing is generally not particularly puncture-resistant. So what is one to do?

The holy grail of one tyre that can do it all does not exist, but you can use a set of search parameters to help guide you to the tyre that will keep you happy for the majority of your riding. The sad truth is that regardless of what is chosen to shod our steeds, there will always be a time when the tyres are hopeless for the extreme conditions that one is experiencing at that specific time. It will happen... but it’s OK! The trick is to choose what works for you most of the time, not cater for the ‘what if’ scenario.

As with most of my own equipment choices, I look at what an entire season of riding will encompass, terrain-wise, and the conditions I will be riding in. An honest look at this easily narrows down the choices. Where things start to go awry is when we look at what everyone else is riding, what we see in the media, and listen to hearsay. This can horribly confuse the issue. The Best is to make one’s own choices, based on a filtered view of the myriad of info available.

The front and back tyres of a mountain bike have completely different jobs to do. The front is the tyre that gives us the confidence when we tip the bike into a corner, and is solely responsible for what the rest of the bike does. If one doesn’t trust the front-end of a bike, there is no confidence to push harder and maintain a good pace. Meanwhile, the rear tyre is really just along for the ride on an XC bike. Its job is to give just enough grip when cranking up those river-crossing embankments and to roll as fast as possible. Therefore, it’s ok to have different tyres on front and rear.

Puncture-protection has a trade-off. A tyre with reinforced sidewalls and a cap of butyl under the tread has two big drawbacks: One, the tyre gets heavier with each puncture protection measure, affecting the bike’s ability to accelerate, brake, turn, etc. Two, a stiff, thick sidewall and tough carcass isn’t very supple so it therefore doesn’t conform easily or quickly to whatever surface you’re riding on. Therefore it doesn’t perform very well. On the other hand, the upside is that a tough, strong tyre is absolutely necessary when traversing sharp rocks and Kalahari camel-thorn country!

Tread patterns can deceive. Some seemingly aggressive patterns can roll faster than you think and some stripped-down, racer-edge semi-slicks can be just the right trick. Generally, skill levels and use determine tread patterns. Novices favour outright grip while experienced racers are willing to work around a stripped down tyre for the extra ‘boost’ it’ll give when things open up.

The majority of what we ride here in SA can be termed hardpack/loose over hard. What this means is that our clay-based soil gets baked hard under the African sun, so it starts to resemble tarmac with a bit of dust scattered over the top. An almost semi-slick would be ideal, save for the “dust-over-crust” scattering of dust sitting on top of the hard-baked foundation, which tends to act like ball-bearings. But when it does rain, it’s torrential. To be honest, not much works in a river, except a pure mud-tyre (which is like a tractor in the dry). Best is to look for a tyre that doesn’t “pack-up” too much with mud.

My best advice is to take these pointers, look at what’s available and then ask your local bike shop for further advice and their own opinion. Many of the staff ride the local conditions and have already done a lot of the research ‘leg-work’ for you. And remember, shiny-side up, rubber-side down.