Mullet: part 1.

26 07 2019

Mullet? reverse mullet? party at the front, business at the rear? who knows what the terminology will settle on, but different wheel/tyre sizes on the same bike is seemingly a hot topic at the moment.

Now, bikes like these have been around a looooooooong time. Ibis and Cannondale stick out in my memory for producing bikes with smaller rear wheels before there were disc brakes or suspension. Then there was the Trek 69er line up.

My first experience of riding a mullet bike was at the singlespeed worlds in 2007. My friend Damo brought his Cog bikes over to race from Australia and he was a big proponent of 29 front, 26 rear. The bike rode really well. for some reason you could throw weight over the rear and unweight the front more easily than on a full 29er. Perhaps because of the smaller diameter and therefore shorter stay length. It was fast in the corners and felt nimble to ride in the tricky stuff. The 29er front maintained the roll over and I didn’t notice any loss in straight line speed. The rear didn’t feel like it was moving with any greater amplitude over bumps or steps.

The why’s and wherefores of the effect (or not) of wheel size, weight and gyroscopic stability are areas of great discussion. A few years ago there was a partly interesting thread on empty beer about the gyroscopic stability of wheels on fat bikes. My take on it was that although there shouldn’t be any clear discernible effect from changes in wheel mass or size in any real terms (because they are all in reality, broadly similar), in certain circumstances, there might be. For example, when in the air or turning and leaning.

Why? sit in a swivel chair and hold a decent size, rotating wheel in line with your body. Then hold it at an angle and the chair will rotate. Different sizes of wheel exert different forces in this circumstance. A 2″ diameter wheel may not rotate you. A 26″ definitely will. My view is that there might just be enough difference at different lean angles and radiuses of wheel to effect the handling of the bike. Maybe.

Recently, a new company called ‘Mullet Cycles’ arrived. Their technical blurb is a little hard to decipher but I suspect there is some truth in there. Now ‘scrub radius’ is a concept looking at suspension and wheel geometry. read about it here. How to apply this to bicycles is tricky, but there is no doubt that when leaned, the point at which you are weighting the bike and the lean angles, turning radius and traction are affected. Worth reading this probably.

Wheels on a bike do different things. So it seems sensible to prioritise in order to get the best out of the system. Loic Bruni, current leader in the DH World Cup and Martin Maes (EWS honcho) are both racing mullet bikes. Loic at least is known for his detailed and data acquisition approach to racing. There certainly doesn’t seem to be a significant loss when moving to a mullet set up. I think it is well worth experimenting, as long as the frame is not pushed into weird geometry by the switch.

Following my experience with Damo’s bike, and with the evolution of the 29+ tyre segment, I ended up using a 29+f/29r set up on my Jones for a while. It is a rigid bike, of course, so the increased ‘plush’ up front was a boon, but the low traction Knards limited things somewhat.

As a result, I experimented with a fat ‘snow’ tyre up front and a 650b x2.6 rear (the original b+ tyre, the wtb Trailblazer). Then when B fat became a thing, This provided the perfect set up (IMO) for the Jones. It slightly affects geometry – pushing the angles back a little, mitigated by rotating the EBB and thus increasing relative bb height and increasing seat angle, whilst retaining the slightly slacker front end.

 

Soon after this, my primary tyre set up was to look to a larger front tyre and or wheel for all my bikes. The fat bike went to a 26×4.5 then 4.7 with a 26×3.8 on the rear. Or sometimes a 27.5×3.8f and 3.0r. Or sometimes a 29×3.0f 27.5×3.0r. My vertigo cycles rigid mile muncher, Maul, went to a 29×3.0 front, 29×2.2 rear then backed off slightly to a 29×2.6 front, 29×2.2 rear.

Kraken, was designed around a 27.5×3.0 front, 27.5×2.8 rear which worked well with the 130mm travel fork. Originally, I had been keen to use a 27.5×3.8 Hodag which in true measurements is only slightly larger than the Highroller 2 when mounted on a 45mm i rim. I had also thought this bike might occasionally be used with a rigid fork and 29×3.0 Minion front wheel, but it is so good the way it is I have never wanted to dismantle it. So this brings me to Leviathan – the fraternal twin of Kraken….and my first bike designed specifically to be a mullet. More on this in part 2.

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Prototype.

11 06 2019

Well, the first prototype was ok, but by the time I was nearly finished, I was pretty sure I could make a better version. So it goes with prototypes.

Rewind. The need. Bikepacking with a bar harness, over the years, has been made much better by efforts to make the harness have 4 points of mounting. The potential problem: some handlebars don’t like having clamps beside the stem clamp, either because of the material (carbon bars occasionally need metal reinforcement at the stem clamp and the manufacturers won’t allow clamping to non reinforced areas). or because of the shape (alt bars, I’m looking at you). The solution: make a steerer mounted clamp that will deliver an auxiliary bar, ideally below, the handlebar. Boom, 4 points of mounting.

If the mounting points are fairly spread and wide and the load is not too heavy you could get away with a very light clamp as the secondary, non weight bearing part.

Fast forward to prototype 1: aluminium steerer spacer, 20mm high, 2 acetal rods and a carbon fibre tube. Can mount below or potentially above the stem. Issue? fugliness. Other issue? amount of steerer real estate.

Prototype 2 will be considerably more svelte. This is achieved because a lightbulb went on and I realised I could make a strap system between the handlebar and the auxiliary bar that means it doesn’t actually have to have any inherent rigidity, other than a slight offset to clear the head tube.

Some initial sketches gave way to lots of beard stroking about how I was going to make the offsets. Initially i’d thought to mount a carbon fibre tube ahead of the steerer and make some straps that would have a carbon fibre strip sewn into them, then around a second carbon tube.

In making the initial aluminium steerer spacer, I decided to change tack and instead of bolting a carrier to the front of the steerer spacer, bolt to the side, slightly offset with spacers and have 2 metal struts (in this case I will be using a downhill, direct mount ‘riser’ kit). these will then have the auxiliary bar attached, though again, I’m not absolutely 100% sure how so far.

Getting there…

 





dRj0nbagworks.

11 03 2019

Well, I’ve been sewing again. a few days off and bad weather and this is what happens. Idle hands and all that,

First up was an ultra light bar harness, with 4 point mounting for either Jones Loop bar, or a Bar Yak Ultra. The benefit here is reduced weight and amazing stability for your Shredpacking adventures. This has a small carbon fibre tube integrated to give it rigidity on a lateral plane, whilst retaining light weight construction throughout. VX33 on top, in Camo and Gridstop dyneema for the underside.

To go with that I made a DCF Hybrid double ended roll top bag. this is light, waterproof and the perfect size for my shoulder season kit. I might make one with the lighter hybrid fabric as this at 170gsqm feels ├╝ber robust.

I taped the seam, so this is waterproof – which makes packing it super easy. it is around 16cm diameter and 46cm long.

Lastly I made a bag for the Strap Deck. This is the latest ‘bagworks product and it is being a wee bit sluggish to catch on. I reckon because I have been ordering in low numbers, they are relatively expensive for what they seem to be. However, add a bag such as my custom version, or a Revelate Polecat, or even just a dry bag if you use Voile Straps and you can secure a heck of a lot of stuff even with the medium sized Strap Deck. I’m confident in time they will become a ‘go to’ item for ultralight bike packing. The bonus is that they are subtle when no bags are mounted, and they do not require straps around the frame to stabilise things unless significant weight is carried.

I am a huge proponent of splitting kit up and placing it around the bike in such a way that there isn’t too much mass on the front, or under the saddle specifically – keeping handling more ‘normal’. This helps if you bikepack Singletrack.

The bag is made from VX33 Camo, the same as the Harness and then it has a Liteskin LS 42 roll top closure on the portion that will see less abrasion. Its light and 11cm diameter 26cm long with 4 rolls and fits a medium Strap Deck beautifully.

It’s fun pushing things on a wee bit. Next is to actually get a weather and time window to go use the stuff!





Making things.

8 03 2019

A few weeks ago, we had amazing February weather. I rode day after day – not far afield, though F.B.R.O.T.Y happened. But, it is now back to the maritime rainy/windy pattern that is typical of West Scotland, so I have been making things.

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With davechopoptions, a trail was born, then another and then another. This is likely in response to the foresting of my local riding woods. It is a real shame to see some of the trails I like riding the most over the last few years, disappearing. However, in fairness to the team who are harvesting, they are doing a stellar job of preserving what they can.

Goodbye, old friend. I have spent countless hours enjoying riding and sometimes just sitting with you.

I started sewing again – this time a special project – a top tube bag (gas tank bag) for my friend Mark Bentley. Admittedly, the first version was not up to scratch, but I was very pleased with version 2. Gas tank bags need a lot of extra work as the trick is to be able to use them one handed. As such, they need to have stiffening panels in the sides and to protect items stowed of a more delicate nature, padding on the bottom. trying to sew these in is a beast, but I settled on a process that allows me to get nice straight seams and the padding is in a separate sleeve that is held in by velcro and the cross velcro side to side reinforcement. Next up will be a very lightweight bar harness that I have been thinking about for a long time. It will have a carbon fibre cross member to gain stiffness and utilise 4 point mounting for either Jones Loop bars, or the Bar Yak system. Stay tuned.

The bag is a Liteskin LS 42 laminate outer with plastic shim stock sides and a x-Pac VX21 inner in white to aid finding things, like jam sammies.

One detail that is essential is the range of the velcro attachment to the top tube. The front is to marry up with a DeWidget, so that needs a simple webbing cross strap. but you need to have an idea of how big a top tube you will be attaching the bag to. You can of course use a long section of velcro, but I prefer polyamide webbing. Anyhoo, it turns out Mark’s Cotic has a 41mm top tube – exactly the same as the ultra rare Vertigo Cycles cowbell and bottle opener to make sure fit is perfect.

The other thing I want to make soon is a bag for the Strap Deck. I’ve been playing around with ideas – from a dry bag with integrated velcro straps, to a simple bag held by Voile Straps.

In some ways, Revelate have already made the perfect bag for the Strap Deck – the Polecat. But I’m going to keep thinking on it.

I’m looking forward to Singletrack world’s and the Bikepacking.com reviews – I love them for attaching anything a bit bulky, but not too heavy to the bike.

(click here to see a video – Vimeo being a bit strange…)

Lastly, I learned to cut threads on the lathe and made an aluminium version of the port DeWidget Mark made initially from Delrin, which can mount above the steerer, and act as a top cap. Highly versatile, it can run the ‘double dangler’ feed bag plate and of course, holds the gas tank absolutely rock solid while you go shredpacking.

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Margins.

26 01 2019

The margins of the year just ended and the new year begun. It’s been strangely mild, a wee bit of snow but not much. Snow Job – my fat bike – has been deployed and has gained a Fox Transfer dropper – a huge boon as I have been fully assimilated to ride with the ability to drop my C.o.G. I find bikes where I cannot drop the saddle nerve wracking nowadays.

I had hoped to get out on a bike packing or maybe a bike/raftpacking mission at some point, but time seems to have evaporated. Instead, I have explored the local trails with a closer eye and even foraged for trail-side food at times.

The dRj0n bagworks project has been fun – I just put an order in for more of the stem/feed bag adaptors for the original DeWidget and along with more DeWidgets, 2 sizes of the Strap Deck. Logan at Bikepacking.com has a full ensemble on test and I hope to get access a wider market as a result of his (hopefully positive!) review. There has also been some work on a Garmin or Wahoo 1/4 turn top hat adaptor for the DeWidget. We will see where that goes…

Next up is a handlebar harness designed to utilise the Bar Yak Ultra…more soon.

Metal work has not happened, but I have been researching how it is best to machine titanium because I want to make some Ti thumbscrews. We’ll see ti is sticky and the swarf is a real fire danger.

Onwards.





Strap Deck.

8 12 2018

I’ve been interested in alternative ways to carry stuff on my bike – rather than on me – for a while now. Once you have tasted the freedom of unencumbered riding, you can’t give it up.

Bottle cage bosses and adaptors have been a focus, as have the straps offered by Backcountry Research.

I like the concept of the King Cage Manything, but don’t have a bike with a triple boss and also don’t have much need to carry as much as a Manything will take. As such, once the DeWidget rolled off the 3D printer, I got around to reviving an idea I had back in 2013. Basically it is a double bottle boss bolt cage for bags.

The use of Voile straps has been an eye opener. When you get into Packrafting, you can’t help but love the wee buggers! the stretch and tackiness is perfect for mounting a bike (or anything, really) to an Alpacka raft.

In time, the 2 things seemed to coalesce in my mind and the Strap Deck was born. The plate, which in time will be available in 2 lengths – one with 4 slots offset, one with 5 is not) take the full size straps and will also work well with the soon-to-be-released smaller straps for lighter loads.

Mark of Bentley Components was, again, absolutely on it with prototype construction and advice. I am truly indebted to him for his help and advice on all of my current projects. Go buy one of his carbo loading devices – they make awesome gifts.

The straps allow you to mount pretty much anything to the cage though I would urge caution with the weight. The M5 bolts ( I suggest button head bolts – such as these from Pro Bolt) are not really strong enough for large, cantilevered weights) are sunk into the cage to reduce friction on the load and the rubbery straps grip whatever item you choose to mount. When not in use, pull the straps and it is unobtrusive.

There will be an initial very limited run available from Backcountry.scot to test the water.





EDC/bike tools.

3 11 2018

Stashing tools inside the handlebar has been intriguing me recently. I have already made a dyna plug inserter (that holds a spare chain link) inspired by Joel Dunkl.

Next I made a bar end cap that also acted as a 1/4″ bit driver and has a tube of bits attached to it too.

Then I got my mitts on a Clever Standard Chain Barrel and made a different sort of bar end plug that will adapt to different id bars and is carbon safe, also.

I’m not sure where I am going with all this but it’s been fun.