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Why different tyres front and rear?

dixonpjdixonpj Posts: 75
edited July 2007 in XC and Enduro
It seems quite common to run different tyres front and rear. Why do people do this, and what features should I look for in a dedicated front/rear tyre?

In case it makes any difference, mine's a 2007 Trek 8500 hardtail. I'm looking to upgrade the mid-weight, middling performance Bontrager Jones ACX to something faster and lighter, ideally tubeless compatible. I like the look of the Continental Speed King Supersonics, but I'm unsure whether they're tubeless compatible, and even if they are whether I ought to run something different on the back.

Cheers,

Paul

Posts

  • The SpidermanThe Spiderman Posts: 5,625
    I have a grippy Schwalbe Nobby Nic up front to stop the front washing end washing out,when things get a bit slippy,but a lightly treaded Racing Ralph rear to give me an extra turn of speed.If the back slides,a bit its easier to correct.

    In the winter I stick a Nobby Nic on the back too.

    I think you can get the Speedking in a UST version,but of course you could use the regular non UST version with a no tubes kit.

    Some folk suggest using a Speedking on the front with a Panaracer Razer on the rear.
    (The Razer is very similar to the Racing Ralph.)
    2006 Giant XTC
    2010 Giant Defy Advanced
    2016 Boardman Pro 29er
    2016 Pinnacle Lithium 4
    2017 Canondale Supersix Evo
  • nutcpnutcp Posts: 169
    Because the front and rear tyres do different jobs - requireing different 'tools' for those jobs. That's why. It really makes little sense to have exactly the same tyres front and rear on any two-wheeler. Reasons:

    60% of weight on the back tyre, 40% on the front
    100% of drive through the back tyre, 0% through the front
    70% of braking effectiveness through the front tyre, 30% through the back
    80% of front wheel skids result in in a crash, but rear skids are often OK
    Front tyre can be run soft without problems, a soft rear feels awful

    If people wised-up and used a larger, gripier, softer tyre on the front, they'd soon work out that suspension forks are less important.

    I go rigid with a 2.3 at the front and a 1.9 at the back. The front runs at 20psi, the rear at 40. The front tyre has aggressive edge knobs for cornering grip, the rear is less aggressive for better rolling. This is ther result of much experimentation and seems to work perfectly for me in most XC situations.
    bikebore
  • al_yrpalal_yrpal Posts: 102
    I am a beginner, and I have experimented with tyres since taking up MTBing about 6 months ago.

    I looked around an expensive MTB shop and noted that many of the bikes had different tyres on the front and rear. This makes a lot of sense to me, and I have experimented quite a bit because tyre choice is critical. I ride on mud chalk, roots and forest trails, but not rock (so far)

    I have five types of tyres in my garage. I started with cheapo Toigas that were fitted to my Kraken Hardtail. Then it dried up and apart from their weight these tyres were a bit too knobbly and sticky so I fitted Schwalbe Land Cruisers (I actually did a 400 mile road cycle tour on these). These are perfectly adequate for rear wheel grip and front wheel directional stability off road when its completely dry.

    Then, when it got muddy my rear wheel kept spinning so I kept the Land Cruiser on the front and put a Panaracer Trailraker on the back. The Trailraker is a great mud tyre and gives loads of traction at the expense of loads of drag on dry surfaces. The Land Cruiser was reasonable on the front in light mud when it was dry. Finally I fitted Panaracer Cinders to both wheels for the summer. These have fairly reasonable traction and low drag compared with the Trailraker and good directional stability on the front and reasonable traction on the back. If there was mud everywhere and it was deep and wet (i.e. next winter), I think I would stick to a Cinder on the front and a Trailraker on the back, this being a reasonable compromise between traction and drag. So perhaps thats how it will end up for the winter. Fitting Ciders to both ends for summer.

    I do have some Maxi's tubeless Larsen TT's which came as original equipment on my Cannondale Rush, I have yet to try them because I swopped them for the Cinders.

    I think it is wrong to just assume that its right to fit the same tyre front and rear, it depends on conditions. What you need is directional stability and stability under heavy braking on the front, with the minimum of drag. On the back you want the lowest drag, but a tread that gives you efficient traction.

    Its all a compromise between stabilty, drag and traction

    Al
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