Muddymoles mountain biking in the Surrey Hills and Mole Valley

Mucky Nutz Butt Fender review

Posted by Matt | April 25, 2012 | 11 comments so far

Mucky Nutz Butt Fender

At one point today, as I looked out the window, it seemed that the rain was coming from several directions at once. Not just down, but horizontally in one direction and diagonally from another! Weird. But every cloud has a silver lining and the upshot of it being the wettest April in years is the chance to test some mudguards.

Well, Mucky Nutz Butt Fenders at least.

Butt Fenders are rear mudguards newly developed by Mucky Nutz. Shane sent me a couple for test recently but since they arrived during drought conditions it’s only recently I’ve had the chance to try them.

In truth they are not precisely mudguards, rather a kid of vestigial tail fixed to your saddle. The idea is they keep mud at bay in a ‘barely there’ way while presenting as little impediment as possible when hanging your back side off the saddle.

The barely there part is an easy tick, they really are pretty unobtrusive, particularly the black version that Dave was trying. This will come as no surprise to riders with the Mucky Nutz Fender Bender on the front of their bike which are well known for providing stealthy mud protection.

Similarly, the Butt Fender cause very little trouble in off the saddle moments as they simply flex downward and out of the way. They are quite flexy so even if you snagged your shorts on them they would just bend underneath you as you sat down.

The Butt Fenders fix under your saddle using some cleverly positioned holes in the plastic material they are made from, taking seconds to fit, even if you need a few moments of head scratching. They weigh just 19g if that sort of thing bothers you so would be an ideal race ‘guard.

Result from using the Mucky Nutz Butt Fender

What you’ll see from the photo of my (rather tidy) backside though, which was taken at the end of a 29 mile ride to Newlands and back, is that the Butt Fenders seem to follow Pareto’s Law. Or, in other words, the 80:20 rule whereby they keep 80% of the dirt off, leaving 20% to get through. Some might argue the other way round judging from the picture.

It would be wrong to jump to conclusions though, parts of Sunday’s ride was through large hub deep puddles filled with clay and water so quite a big test. I wouldn’t expect the small Butt Fender to keep me clean in these circumstances and while the trail looks dry in the photo, in truth there was plenty of mud about. My saddle remained completely free of mud and even if my lower back got a light coating of mud there was never enough to wet me.

Another factor to consider is how high my saddle is from the rear wheel, just my particular set up but one which will vary from rider to rider. A different rider with a saddle closer to the wheel can expect the Butt Fender to catch more of the dirt.

Overall I’m quite happy with the Butt Fender and will use it in those in-between conditions where there’s lower mud levels to worry about, as it’s such a discrete device and so quick to fit. For extensive mud, well, you really need something a bit more comprehensive although in an emergency I’d use this as it’s certainly better than nothing. For less than £7 it’s something of a bargain.

Filed under Accessories, Reviews in April 2012


About the author

Matt is one of the founding Molefathers of the Muddymoles, and is the designer and main administrator of the website.

Having ridden a 2007 Orange Five for many years then a 2016 YT Industries Jeffsy 29er, he now rocks a Bird Aether 9 and a Pace RC-627.

An early On-One Inbred still lurks in the back of the stable as a reminder of how things have moved on. You can even find him on road bikes - currently a 2019 Cannondale Topstone 105 SE, a much-used 2011 Specialized Secteur and very niche belt drive Trek District 1.

If you've ever wondered how we got into mountain biking and how the MuddyMoles started, well wonder no more.

There are 11 comments on ‘Mucky Nutz Butt Fender review’

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  1. Karl says:

    Had mine for a while now and it’s great.. Very light, and stops the wet getting in the crack of yer bum. S’all you need..

    Only slight hiccup is catch it a bit when hanging off the back on the knarly, and also when throwing a leg over the saddle sometimes..

    Minor details tho for a fit and forget..

    Adds a bit to the look too I think.. I like a cantilever..

  2. Big al says:

    Looks a bit 1980’s GTI!?

  3. Dandy says:

    This sounds like the ideal solution to my rear mud guard problems. Many of you have kindly stopped to pick up my rear Crud Guard after an enthusisatic use of the full 150mm rear travel on my Pace has resulted in the guard being ripped away by the rear tyre.

    I was thinking about some sort of zip-tie leash to secure the guard to its mounting, but the Butt Fender seems a more eminently practical solution to my needs.

    I will keep the full guard for my winter hard tail though, for that ‘closer to the tyre, catch everything’ effect.

    • tony says:

      What, you have an non-cracked Pace frame? I thought that they had all gone to the big aluminium smelter in the sky?

      • Dandy says:

        Au contraire, Blackadder ! My ‘big boy’ Pace 506 has withstood all that I can throw at it, That’s hucking off six, sometimes nine … err … inch drops; with no sign of failure. Says he hastily touching wood, crossing fingers, maiming rabbits for their feet – not v lucky for them, were they?

        It was only the nancy-boy Pace with the paltry 130mm travel that seemed to suffer at the punishment dished out by Der Huckmeister 😉

  4. Dave says:

    Much as I laughed at BigAl’s comparison to the effectiveness of this being similar to the Spoiler on a 1984 XR3i I suspect that in reality Karl has it about spot on.

    What it does is stops the mud heading up onto the back of the saddle and soaking your arse that way. It’s much the way I feel about the front version, it stops most of it but is not a full solution like an SKS Shockboard. However, it’s minimal, cheap and effective at what it sets out to do which is making riding that little bit more comfortable.

    • Karl says:

      After a true mudfest Moles ride I should add, that you can’t lift off your saddle if you want to stay dry as the protection area is too small and you get splattered..

      So, not great for muddy techy, or muddy out of saddle climbing.. mmm..

  5. O says:

    It’s shameless how the guys at Mucky Nuts just seem to have copied Ass-Savers!!

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