[Closed] Why are plus tyres a bit naff in the mud

I was anticipating slideyness when I bought some 27.5+ rims but I've found the Spesh Purg 3.0 tyres really good in the slop. And not even at super low pressures either! Got em £20 an end too.

Stache owner here. Agreed... They are not great. Even running aggressive vee bulldozers and minion at 12/10 psi they are not as grippy as my 29er with "skinny" 2.35 ikons. Think the thinner tyres cut through the top slop and grab the hard stuff underneath. The larger contact patch of plus tyres floats and slips in the slop.

Heck my cx bike with 40mm nano's is better in the mud round swinley. But when its dry... The grip from the plus tyres can't be beaten and that's when the bike shines.

Cos they float on top of the mud, rather that cut through to the hard pack underneath (like skinny mud tyres)

And the tread patterns generally aren’t that aggressive in the main, from what I’ve seen, thought that’s changing.

I've found 2.8" Nobby Nics to be a liability in the slop. Going to bite the bullet and buy Magic Marys.

Imagine the grip a 2.8 Short would give?

A lot of + tyres rely on a bigger contact patch and smaller knobs for the grip.

That doesn't work in the mud,

But on the flip side that's why they're so much fun in the dry, fast but still with good grip.

I think its mainly caused by mud being quite slippy

Its all in the tread have a stache and the Bonty tyres get very hairy in thick mud don't clear well at tall more a dry tyre yet on Farley fat bike the tyres are Bonty Hodags which are 27.5" 3.8s and are amazing in mud wish they put them on the Stache in 29er plus Hay Ho.

Narrow mud tyres sink in and then grip on what's underneath (or just push sideways on a lot of mud).

Fat tyres put really low pressure on the ground, which translates into low shear stress that the mud can withstand.

Mountain bike tyres and plus tyres are somewhere in the middle, so rely on a lot of tread.

Same reason the skinny tyred airportable landrovers were better off road in mud than the standard ones we had in the army. One cuts one floats

Let's face it, they're not going to bite in like Trailrakers or spikes of the equivalent but found my 2.8" NNs alright today if a little draggy on rear in slop.

tbh I know I wasn't riding in true slop today but came away fairly impressed on grip running 17.5 front and 19.something rear fir a fatty like me.

My riding bud was on 3" NNs and seemed competent enough on them but yeah sidewalls are thinner than sausage skin.

think WTB offer some good alternatives for wet slop but at weight penalty.

Back in the 90's I used some 1.5 inch continental pc's that were amazing in the mud. They sank down and got grip under the mud. As above, a wider tire floats on top where there is less grip. Great for fat bikes on sand though.

2.1 storm control is by far the best tyre I’ve found for mud  but appreciate others will disagree.

"singlespeedstu

Imagine the grip a 2.8 Short would give?"

Aye but do you want to pedal it up a hill? Or for that matter carry it home from the shops 🙂

Poor technique... 🙂

2.8 DHF on 27.5+ up front. No problems at all in the mud.

2.5 DHF on 29 up front - good but less grippy in the mud than plus. Faster though, just not as much fun downhill.

Thats what I’m riding at the moment.

I was so close to owning a plus sized bike but due to a size mix up I ended up with the 29" wheels. This weekend I was out in some nasty nasty conditions and I could not fault to Bontrager Team Issue 2.4s!

Same weight over a wider contact patch = less pressure so you sit on top

When there is slippy stuff involved if you can dig into it then it doesn't give as easily: hence mud tyres are designed narrow i.e maxxis beaver is 2.0 etc

Depends on the consistency of the mud and the tread on the tyre

I run DHFs 2.8s front and rear and they are normally great unless its proper loamy mud then its a test of ability.. and sorry but getting the bike sideways is all part of the fun

I know this is a Plus conversation but what are fat bike tyres like in the mud and on peat bogs. There's a lot of moorland locally that I'd like to explore away from the beaten tracks. This kind of terrain is ok on my drop bar 29er but it might be fun to try on a fat bike.

I don't ride plus tyres, but 29 x 2.4 (ardent rear/ magic mary front) are pretty wide. Turned up at one of the local lesser-used singletrack loops yesterday, which is an absolute bog in winter, behind a couple of guys on CX bikes thinking they would be in my way, but couldn't get near them - whenever I lost traction on an uphill, they didn't and I just couldn't get moving again.

In reality I think they were just much faster then me, but I couldn't help thinking a set of narrow nobbiles that cut through the slop would be a better choice for the winter mudfest.

It seems to depend very much on the type of mud, the tyres and your preference. Some will say that fatbikes are terrible in mud, but I'm quite happy with a 4.8" Surly Bud on the front in winter. But that's on peaty/sandy Scottish "mud". For reference I run Jumbo Jims in summer, which really don't seem to like the mud. Although this year I've kept the JJ on the back as I prefer the lower rolling resistance (compared to the Lou I ran last winter) and I don't mind a bit of sliding at the back. It's all personal though.

I'm not sure how much weight plays a part, but it's worth I think noting that when conditions are dry and there's plenty of friction to be found, F1 and Rally cars run very wide tyres, when it rains they go narrower to ensure they can cut through the rain rather than aquaplane and in the case of Rally cars when they're in the snow they go very narrow indeed.

Bearing in mind most of MTB innovation comes from either 'Cali' where is rarely rains or Canada when it's pretty much a seasonal sport, perhaps this one isn't best suited to the UK where it's often wet and we ride all year?

I don't ride in the mud anymore. When I did (and this was in the dark and distant days of 26" wheels), a mud specific tyre had a 1.5" diameter!

so you have a compromise of a wheel size, with a compromise of a tyre size, and the ride is compromised.

and ... every mud is different!

In certain "mud conditions (and snow conditions? or sand)" FATBIKES are great. In other they are terrible - like floating...

"I know this is a Plus conversation but what are fat bike tyres like in the mud and on peat bogs. There’s a lot of moorland locally that I’d like to explore away from the beaten tracks. This kind of terrain is ok on my drop bar 29er but it might be fun to try on a fat bike"

I tried to run 4.4 Jumbo Jims through the winter and they are dangerous, recently changed to Surly Bud/Lou 4.8s and the grip is off the scale, they roll well too. I'm going back to JJ's in the spring as they are lightning fast!

Similarly, JJ  in dry, Minion FBF both ends in clag (Both 4" versions).  I'm generally doing better up wet mud over chalk hills than my SS with Beaver rear, but that's cos I can sit down on the (geared) Fattie!

Has anyone suggested there might be a bit of placebo effect?

They don't grip because you don't believe they'll grip, so you tense up, so they slide.*

*works with all tyres in all conditions. But only up to a point. Then the laws of physics still take over.

I think in the UK they probably only make sense if you can either have a winter and a summer mtb, or the option of swapping between 27+ and regular width 29er wheels on the same bike depending on the seasons...

Otherwise just stick to 2.3ish wide "normal" tyres for year round use.

Interesting. I ride in the Mendips which means mud for much of the year. Riding my plus bike with 3.0 purgatory front, NN 2.8 rear seems to work fine for me compared to my riding mates on a variety of bikes and tyres.

Now that said my setup above definitely feels different to 29er wheels and bonty mud tyres ( my favourite mud tyres). The plus tyres are less planted (ie they break grip sooner) BUT the slide is completely predictable and slow. Once you get over the feeling of the bike moving it's a blast and never an issue riding anything you'd try on normal mud tyres. Then add in the ability to absorb rocks and roots and it's a great choice.

All imo of course and I am generally a decent rider in mud but the idea that plus bikes aren't good in mud is fundamentally wrong to me.

BTW p-jay, aqua planing isn't an issue in mtbing ( nor Road biking as it goes)

<span style="color: #444444; font-size: 12px; background-color: #eeeeee;">Interesting. I ride in the Mendips which means mud for much of the year. Riding my plus bike with 3.0 purgatory front, NN 2.8 rear seems to work fine for me compared to my riding mates on a variety of bikes and tyres.</span>

Different sorts of mud innit. Come a bit east into chalk and clay country and plus struggles a bit (though I'm on summery WTB tread rather than anything biting). But it's a blast here in the dry - so I'm going dual wheel on the next build, with 29er  Bonty muds for winter use.

<span style="color: #444444; font-size: 16px; background-color: #eeeeee;">All imo of course and I am generally a decent rider in mud but the idea that plus bikes aren’t good in mud is fundamentally wrong to me.</span>

I just don't think they behave as well as a ''regular" tyre. Which can be part of the fun I admit.

Besides it's difficult to define fun. Sometimes you want predictability so you can get where you're going as quickly and tidy as possible. And that can be fun too .

I think it’s the shape of the contact patch - a long narrow contact patch is much better naturally at going in a straight line. Like a ski vs a snowboard.

Not great in mud, but as said many times already, hardly a surprise given that they are going the opposite way to the design of a dedicated mud tyre.

I have found so far though that due to the big contact patch they quite often dont slide out to far before finding something they can get a hold of again.

Mud is a catch all term, much like snow

There are loads of different types of snow, and loads of different types of mud

Wet slick mud, sticky clay-like mud, soft squelchy mud, leafy mud, boggy mud etc

I suppose some tyres will work better than other depending on the exact type of mud. The clay like mud is the killer stuff I find, it slows you down so much you can barely move. SS on that is horrific

<div class="bbp-reply-author">chiefgrooveguru
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I think it’s the shape of the contact patch – a long narrow contact patch is much better naturally at going in a straight line. Like a ski vs a snowboard.

The best snowboards for turning are narrow alpine boards, the worst skis for turning are wide powder skis - i dont think you've got the best theory at the moment.

Wet slick mud, sticky clay-like mud, soft squelchy mud, leafy mud, boggy mud etc

All of which will be worse on a wide tyre, the only possible exception being the bog as thats likely on flat ground where you need to not sink rather than have loads of grip

Boats then! Or four wheel vehicles. Basically long skinny things are better at keeping pointing in a straight line. Short wide things are less stable.

A long thin contact patch sets an edge as it cuts through the mud - a wide short one doesn’t have as much length to the edge so is more reliant on the sheer friction of patch against mud.

I am still running Fire xc pros for mud. 1.8 size in 26 inch.