Grouptest: Big and Bald Tyres

February 16, 2009

Benji and his crack squad of sad rubber sniffing tyre obsessives try to convince you of the myriad splendours of a bunch of funny looking fat tyres with bugger-all knobs on them. What’s all that about eh? They claim there’s a brave new world of tyre technology out there, as much part of our future as garlic bread. We shall see…

Tested: by for

Tape Measure Time

There are nearly as many ways of measuring tyres as there are tyre sizes. A chunky 2.1 can sometimes be fatter than a skinny 2.35. Some manufacturers measure the carcass and the knobbles in millimetres and some measure the overall width in inches. Some just seem to make it up.

In order to get a consistent comparison for this test, we measured the tyres ‘knob to knob’ – the outer distance between the tyre knobbles when infl ated. This gives an idea of the width of actual grippy tyre. And we also measured ‘bead to bead’ which is the full width of the tyre carcass spread out widthways, off a rim. This gives an idea of the actually tyre volume and cushioning potential.


Continental Petrol 2.5
Bead-to-bead: 140mm
Knob-to-knob: 65mm
Price: £19.00
Weight: 870g (wire bead)
From: Continental 01970 626777

Some of you may recognise the side knobble design of these tyres – it’s the same ‘Endless Edge’ pattern that is used on their popular Gravity and Diesel tyres. Unsurprisingly the Petrols corner with the same characteristics as those tyres: fairly drifty. Which can be unnerving at fi rst if you’re used to the railing-a-line performance of stickier tyres but after a while you get used to it. The drifting can be a very fun and effective way of flashing quickly around hardpack hairpins. The fairly hard compound made them a bit sketchy on damp rock and the knobbles lacked bite in loose conditions (wet or dry) so these are best suited to dry hardpack. The centre section isn’t as sparselooking as the 2.3 version of this design (‘Flow’). Surprisingly we thought the braking and climbing performance of the Petrols was better than the ‘fully knobbled’ Diesels (which are lacking in ground-grabbing ‘troughs’ in the knobble design). They were just as good at absorbing bumps and had lower rolling resistance (although not that much lower).

Overall: Fast, comfy and fun in the dry but a little too damp-a-phobic for our tastes. Probably a good tyre for summer trail centre visits.

picture-22DMR Moto Digger 2.35
Bead-to-bead: 145mm
Knob-to-knob: 65mm
Price: £23.00
Weight: 750g (Kevlar bead)
From: Upgrade 01403 711611

This was a very surprising tyre – in a pleasing way. To be fair to DMR the Moto Digger isn’t really intended as a XC/trail tyre – it’s designed for messing about on dirt jumps – but we really like these tyres for all sorts of riding. Looking at the tread design and feeling the fairly fi rm compound rubber we fully expected to be washing out left, right and centre on anything except hardpack dirt. At fi rst we ran them with quite low pressure (thinking it would help with traction) but we pinch fl atted them too frequently. With more pressure in them they didn’t flat so easily and were miles faster and still comfy (they are massive for a 2.35 tyre). They also seemed to corner and brake better – even in looser terrain. The round profile with evenly spaced, similarly tall knobbles covering quite far down the sidewalls made for a completely predictable ride. You may not be able to lean the bike over as far around corners and have it stick to the line but you know exactly what the tyre is doing and is going to do which, for us, is a vital aspect with tyres. They’re quite light and durable as well.

Overall: A surprise favourite among the Singletrack Rubber Squad. Fast, light, über-predictable with acceptable loose condition performance as well.

picture-32Kenda Small Block Eight 2.35
Bead-to-bead: 140mm
Knob-to-knob: 60mm
Price: £26.99
Weight: 610g (Kevlar bead)
From: Moore Large & Co 01332 274200

Oh look – a Kenda tyre’, you may be saying to yourself, ‘this is bound to get a good review because the Singletrack guys love Kenda’. In many ways the whole idea of doing this ‘big but bald’ tyre test was inspired by our experience with the smaller (1.95 and 2.1) versions of the Small Block Eight. We fully expected these 2.35 versions to be as ace but in all honesty they weren’t as good. In fact they were very disappointing. A bit like some of our testers’ opinions on Kenda’s Blue Groove tyre, we don’t think the tread design of the Small Block Eight works on bigger volume tyres. They cornered very well, presumably due to the sticky compound side knobbles but everywhere else they struggled a bit. They didn’t feel particularly nippier than a normally knobbled 2.35 tyre despite the low weight and small knobbles. Traction was okay on hardpack but in looser and/or damp conditions they could slip and slide – hard braking caused a lot of skidding (front and rear wheel). And like all large volume Kendas the sidewalls are a bit on the thin side and pinch prone. Kinda pricey too.

Overall: Classic case of a Kenda tread that works brilliantly on smaller tyres but disappoints on a larger carcass.

picture-42Maxxis Larsen TT 2.35
Bead-to-bead: 145mm
Knob-to-knob: 55mm
Price: £19.99
Weight: 710g (wire bead)
From: MMA 01267 234369

We’ve tested the smaller versions of these tyres before and were very impressed with their speed and grip. So we were very keen to try them in a bigger fl avour. Unusually in this modern age of dual and triple compound rubbers, Maxxis use sticky rubber all over the carcass of the Larsen TT. One thing the Singletrack Rubber Squad have come to learn is that it’s pretty much impossible to go wrong traction-wise with a tyre if the rubber is sticky enough. But as you well know, the problem with sticky rubber is felt in your wallet and your legs – they wear out quickly (and are generally more expensive to buy in the fi rst place) and can be overly draggy on a lot of surfaces that make up a great deal of XC/trail rides. The Larsen TT was a fantastic traction performer on proper off-road – it gripped on to everything without the merest hint of slip or creep – but it doesn’t really offer anything else. Which sounds like a weird thing to say (‘what more do you want from a tyre?’) but other tyres in this test were almost as grippy but signifi cantly faster, more absorbent and less tiring to pedal around.

Overall: Fantastic traction performance but the ‘all over’ sticky compound reduces speed and increases effort. Dual compound version please Mr Maxxis!

picture-52Michelin Dry 2 Reinforced 2.3
Bead-to-bead: 145mm
Knob-to-knob: 60mm
Price: £24.95
Weight: 740g (Kevlar bead)
From: Michelin 01782 401755

Michelin’s mountain bike tyres tend to fall into two camps: super soft sticky ones that are incredibly grippy but wear out incredibly, impractically quickly and harder compound
ones that last forever but sketch out at the merest hint of moisture. So it was with some trepidation that we tried the Dry 2’s seeing as they looked to be of the harder and sketchier variety. Like a lot of tyres in this test, our expectations were wholly confounded. Yes, they could skip about on slimier wet rock but their performance on any kind of dirt was very impressive. They were great on loose dry stuff as well – not surprising considering Michelin’s fondness for testing in the Pyrenees. They also seem to have cracked the secret formula for a tyre with very low rolling resistance and decent levels of traction and good, predictable cornering behaviour. They aren’t the lightest tyres (but aren’t exactly heavy) but we think the trade off of the puncture resisting reinforcing is worth it.

Overall: Another one of our surprise favourites. Near faultless performance and the price is OK considering their durability.

picture-62Nokian Assault-X 2.4
Bead-to-bead: 130mm
Knob-to-knob: 60mm
Price: £17.95
Weight: 1010g (wire bead)
From: Wind Wave 02392 521912

Much like the DMR Moto Digger the Assault-X isn’t really intended for XC/trail riding (it’s for ‘urban and dirt riding’ apparently) but we thought we’d give it a go anyway to see how these tougher, heavier (generally cheaper) sort of tyres behave on the trails. The results were something of a mixed bag. Performance-wise they were actually pretty good – fast rolling but with decent levels of traction when called upon, all delivered in a nicely predictable way. The rubber was slightly softer than most other dirt jump fl avoured tyres and as such didn’t suddenly break away or wash out while cornering or braking. The more open design of the knobbles also meant they coped very well in loose and/or damp stuff. The thick casing was something of a mixed blessing; we didn’t pinch fl at these buggers even at low pressure but they weren’t very supple at soaking up lumps and bumps – it’s worth pointing out that these aren’t as big as the 2.4 name suggests (they’re more like a fat 2.1). And the energy saving potential of the fast rolling tread design is pretty much negated by the heavy weight (they are not currently available in folding bead).

Overall: We liked the performance of the tread and the compound of the rubber but they need a bigger, more supple casing for XC/trail riding.

picture-72Schwalbe Racing Ralph 2.4
Bead-to-bead: 155mm
Knob-to-knob: 60mm
Price: £29.99
Weight: 580g (Kevlar bead)
From: Bohle UK 01743 874496

Again this is a larger version of a tyre that we have already reviewed (and liked). It’s quite an expensive tyre but Schwalbe are a company that put an awful lot of R&D into their tyres – not just the tread pattern but also coming up with specially woven casings and carcass area-specific multi compounds. So it’s not just a case of slapping sticky squares of rubber on to any old casing. Schwalbe’s tread designs are always a bit unusual looking – sometimes they just look plain wrong in fact – but they usually end up being very decent performers. It’s nice that a company isn’t afraid of making odd/wrong-looking stuff. The tread pattern of the Racing Ralph is unlike any other tyre we can think of. There’s no obvious ‘paddles’ or square knobbles – just a whole load of low profi le curvy triangle-ish shaped bits. Anyway, the proof is in the riding and we’re happy to say that this fatter version of the Racing Ralph is as good the skinnier ones – in fact, we think the 2.4 version is by far the best fl avour of Racing Ralph. Grippy in an impressive range of terrain (surprisingly capable in mud as well) and can be run at lower pressure for extra comfort without becoming squirmy, yet is still noticeably easy rolling and fast to accelerate like its smaller brethren.

Overall: Not just a great ‘big and bald’ tyre but a great all rounder tyre as well. Capable and predictable on pretty much anything bar Somme-like mudbaths.

picture-82Tioga Yellow Kirin 2.3
Bead-to-bead: 145mm
Knob-to-knob: 60mm
Price: £29.99
Weight: 850g (Kevlar bead)
From: Extra UK 01933 672170

The Tioga Yellow Kirin is designed as a large volume fast rolling freeride tyre. Its tread consists of many small ramped knobs relatively closely spaced. The knobs also have small slits on the top of them to allow them to spread and grip the riding surface. When riding, the low rolling resistance of the tyre was very noticeable. For such a large volume tyre speed was gathered very quickly. The tyre was sure footed and encouraged fast cornering with good grip levels. When the tyre did become a little unstable it gave you some warning that it was about to let go rather than just washing out. The general traction of the tyre was excellent on most surfaces and even acceptable in wet conditions, considering it isn’t designed as a specific mudtype tyre. The large volume of the tyre provides good cushioning and pinch fl ats didn’t occur, even with the tyre encouraging more speed due to its low rolling resistance. A little on the heavy (and pricey) side but for hard riding heavy hitters wishing to carry speed at all costs then these are well worth a try.

Overall: The tyre does what it should and does it well, encouraging you a little quicker than usual but with no nasty surprises.

picture-92Vredestein Killer Bee 2.4
Bead-to-bead: 148mm
Knob-to-knob: 60mm
Price: £21.25
Weight: 650g (Kevlar bead)
From: Chicken Cycles 01582 873329

One the freakiest looking tyres we’ve ever seen. Looking at it you’d think there’s no way that this tyre will grip on to anything off-road. And yet, it does – very impressively as well. The Killer Bee is testament to the vital properties that footprint size and rubber compound have on a tyre’s performance. After all, there’s not much tread on this tyre at all so carcass and compound is pretty much all it’s relying on. It feels too much of an exaggeration to call the tread design ‘knobbles’ – they’re more like ‘pimples’. The Killer Bee is a large volume tyre and works best paired with quite a wide rim (to make sure that enough tyre is in contact with the ground) and at fairly fi rm pressures to avoid the squirrely squirming and pinch potential of lower pressures. It’s are very light tyre which, combined with the incredibly low rolling resistance, means a noticeable increase in speed with seemingly no extra effort required from the rider. They’re better suited to rockier terrain (even if wet) as the lack of knobble makes for sketching and skidding if making sudden moves or braking hard over damp dirt.

Overall: We don’t know how this tyre performs as decently as it does! Super fast on hardpack and rocky terrain.

picture-102WTB Weirwolf LT Race 2.55
Bead-to-bead: 160mm
Knob-to-knob: 58mm
Price: £29.99
Weight: 740g (Kevlar bead)
From: Raleigh 01773 532 600 and Hot Wheels

Inspired and designed for WTB by cross country and downhill racer Mark Weir. Normally if there’s someone’s name on a tyre you can take it with a pinch of salt but Mr Weir has had a great deal of input into this tyre. And to our minds, he’s come up with the perfect All Mountain tyre. Ostensibly it looks like someone’s just put a normal WTB Weirwolf to a belt sander but looking closer reveals that there’s a bit more to it than that. The carcass is bigger than the (already quite voluminous) Weirwolf and the tyre profi le is a bit taller and less round. The central tread knobbles are ramped for low roll resistance, but suffi ciently square-edged for impressive braking traction. Large transitional openings between the knobbles do a good job of clearing any tenacious dirt. Even though it isn’t a particularly round profile tyre the performance through corners and across cambers was excellent and predictable. They do take a bit of practice but after a few rides you find yourself choosing to either weight the bike and hold a line through turns or unweight and induce a lovely controllable drift – depending on the terrain or your mood. Their performance in wet conditions was surprisingly good too. They’re pretty light considering their huge size which, combined with the low rolling resistance, means you can ride faster for less effort.

Overall: The perfect All Mountain tyre. Fast, light, comfy, grippy, fun. Stick some of these on your burly bike this summer and see how fast you can go.

Big and Bald Tyres Group Test Conclusions:-

For all-round XC use then we’re giving the nod to the Schwalbe Racing Ralph 2.4 tyres. We’d actually recommend keeping them on your bike all year round – with only occasional emergency use of proper mudspecific tyres if it’s really filthy out there. For burlier All Mountain use there is no better tyre currently available than the WTB WeirWolf LT 2.55. Again, a capable enough tyre with so much going for it that we’re keeping them on our bikes all year round (with a pair of mud spikes in the boot just in case). Destined to go down in MTB history as a Classic tyre (with us sad rubber geeks anyway!) Which tyre you think will suit your riding best hopefully this test will inspire you to at least give ‘big and bald’ tyres a go. Hopefully you’ll be as impressed as we were. They can make your bike faster and more fun without any effort. Can’t say fairer than that really.

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