Just back to MBing and looking to get some new tyres and I see that there are many who mix the brand/tread & size of their tyres between Front & Rear.
I’m not looking for tyre brand recommendations, just the reasons for doing this, so can someone please explain the basics?
Thanks.

Some tyres work better on the front, others on the rear. Widths depend on the type of riding or weather conditions you’re doing.

pretty much always different on mine

tend to be a bit bigger on the front

more knobbly on back (winter) or smoother on back (summer)

The simplest explanation is that you can mix a draggy, grippy tyre up front with a faster rolling, slidey tyre at the back without compromising the rolling resistance too much.

Horses for courses isn’t it.

I also prefer something faster rolling on the back in general than the front (would compromise braking grip too much on the front), and usually prefer a front tyre with more cornering bite whereas I’m happy with a rear tyre that slides a little more.

On the size thing, ever so slightly narrower on the back again usually means it will roll a bit quicker, though also a lot of frames don’t quite have the same kind of tyre/mud clearance as most modern suspension forks do. I recently purchased a pair of Bontrager XR4 tyres to discover that the knobs rubbed on the inside of the chainstays on my bike, so had to fit something else to the rear!

I’m only just getting to understand this but, for my type of riding I need max grip & lowest “drag” on the tyres.

The compromise for me is to go “grippy” on the front & “fast rolling” on the back … the way I get my mind round it is that you feel the drag on the rear, if it isn’t fast rolling, when pedalling any kind of distance. So, on the basis that you afford to let the back slide, go for faster rolling.

On the front however, I don’t really want it to slither about – therefore more grip is required.

Many thanks for responses so far.
From what I gather the preference seems to be a grippy front tyre with a smoother rolling rear tyre.
That was at odds with my initial thoughts of a smoother front with a grippy rear. My rationale was of easier/lighter steering on the front and grippier rear when applying the power so the rear doesn’t slide out on cornering.
Am I totally wrong on my logic?

Heckler: 2.4 f 2.2 r both RQ.
HT & SS 2.35f, 2.1r Ardent / Crossmark

Well, that’s how they are at the minute..

Tyres change for winter…

Am I totally wrong on my logic?

Basically, yes.

The front does the bulk of the work under braking and cornering, the rear puts the power down and carries most of the load. I’m always MUCH more worried about the front tyre sliding out under cornering, or braking, than I am if the rear slides. With a rear tyre slide you can catch it 9 times out of 10, but a front tyre slide and you’re going down on your face regardless. Ultimate grip from a rear tyre is really only an issue if most of your riding is spent cycling through very soft ground, hence why most people use a specific set of mud tyres come winter (with correspondingly grippier, yet slower rolling, treads).

Just got one of these on the front of my hardatil…

Combined with one of these on the rear…

So far so good, the rear is nice and quick yet reasonably predictable under braking, and due to the side knobbles is actually pretty good at cornering. The front, as it looks like, is quite good under braking and cornering, but would be quite a bit slower if it were on the back where the bulk of my weight sits when I’m “just riding along”.

Make sense yet?

Bmxers and DHers have been doing it for years. I used to run 2.5 soft compound on the front and 2.35 hard on the back of the 224 in my DH days.

Yep, all beginning to make sense now mboy, out of interest what is the tyre set up you have ie brand, model & size.

Conditions trump tyre speed IMO… grippy tyres are not all the same (some grip better in dry and loose conditions, others better in wet and muddy conditions). And some rear tyres will wash out (slide) more easily in certain conditions etc. so a fast rolling tyre on the rear is gonna end up lowering your average speed rather drastically if you slide off the trail too often. Some rear tyres slide “predictably”, others unpredictably, depending on conditions. But controlling your rear wheel sliding is far easy than controlling a front-wheel slide, which is why the front is arguably the more critical tyre in some cases.

Best bet is to think of what conditions you’ll most likely be riding in ask about the best tyres for those specific conditions here or on mtbr.com. Then perfect your tyre removal/installation technique and try lots of different ones (a lot of people sell slightly used tyres they didn’t get along with on ebay). There are so many different makes and models of tyre because there are so many different conditions and people have so many riding styles.

I ride mainly in California in the summer (dry and either hardpacked or very loose) and run a skinnier Maxxis Larsen on the rear — its fast and slides a bit, but in a predictable way allowing me to control it easily. It also has decent grip in loose stuff up hill so I don’t lose valuable energy spinning my wheel on steep climbs. On the front I run a wider type with good cornering grip (Kenda Nev, Maxxis Minion) because I don’t want my front wheel slipping on loose rock and sending me over a cliff. I’ll run a semi-slick on the front, however, if it’s mainly hardpack. If the conditions are muddy in the winter, I’ll choose tyres that shed mud better (so they don’t become giant slicks) and have some grip over wet tree roots, for example (which the Larsen is horrible at).

All sorts of other factors also come into play, such as tyre pressure (adjust to slightly change tyre behaviour), tyre compounds (sticker is better in some conditions but will wear out fast). All that stuff can be picked up by trial and error (and applying basic physics).

i quite like using a bigger rear tyre than front on my hardtail.

a maxxis advantage 2.4, it’s huge so works at lowish pressures, it’s like having a little bit of suspension at the back.

it’s not on there all the time (like now), but i think it’s worth trying.