How to fit a G-funk handlebar strap deck system.

16 04 2020

I made a video to explain how to mount a G-funk bar clamp set up on your bike.

 

Hopefully, it is all pretty straightforward. There are a couple of important points

  • Make sure the bolt threads into the cross dowel nut easily. If it doesn’t, adjust the cross dowel until it does.
  • The nylon washers are spacers, you don’t have to use them all. If you mount the Strap Deck facing down (the ideal set up) then you may need them to clear your stems face plate bolts.
  • The nylon washers need treated with care – they are very light and work really well for the intended purpose, but don’t treat them rough!
  • The whole system needs very little torque to set. Less than 2nM – best advice is to snug the bolts up just until you feel them bite a little, then check for rotation. If it moves, snug it a wee bit more and repeat as neccessary.
  • The bolts are button heads so the head does not rub on whatever you mount on the Deck. That means the hex key engagement  is shallow – use a good quality 3mm hex key and make sure it is fully engaged.
  • Consider using purple (222) or blue (243) Loctite on the bolts where they meet the cross dowel.
  • The intended use of the G-funk set up is ‘ultralight’ bikepacking and for extended rides. As such, the weight limit is 1.7kg. Ideally, I would suggest less: *any* weight on the bars is detrimental to steering. If you need to haul winter-ready gear or heavyweight items such as Alpacka rafts, this is not the right bit of kit.
  • I recommend using Voile Straps, as the rubbery material adds to the traction on the bag. The stretch is excellent at absorbing shock, too. The slots of Strap Decks are sized for normal Voile Straps,. but nano also work. You can use webbing straps or even velcro of course.
  • Bottle cage spacing is nominally 64mm and the Strap Deck has oval holes to allow some fudge factor. That means you could use the G-funk clamps to mount a bottle cage under your bars as long as your stem is no wider than ~52mm.

Questions? add as a comment and I will get back to you!





The 3D printer has been fired up.

4 02 2020

Another run of parts getting checked over and packaged up. It’s pretty cool thinking about all the adventures these things will go on…





Being constructive…

18 01 2020

January is not really a month for big, long rides on the West coast of Scotland….it is wet, very windy and dark for longer than it is light. So, I’m trying to keep busy, making things.

1. The lathe. I’m trying to improve rigidity and motion of the various slides. I also wanted to move the milling attachment in relation to the chuck to give me a better range and position of the machine vice. So far so good. I put a bearing in the compound slide, a new brass gib as well and small bearings held by cup ended grub screws for the adjustment on the cross slide. I also altered the way the guides are held onto the carriage – by using longer grubs, held in with loctite and then nyloc, flanged nuts so it will hold its adjustment better. A steel plate was drilled to attach the milling attachment with M8 bolts and altogether I have a considerable improvement.

2. One of the purposes of improving the lathe was so I could make the Strap Deck ‘decaleur’ plate a little more easily. In order to make it slightly quicker to find the centres for the various holes it needs, I also invested in some transfer punches and transfer screws. The former are simply punches of various diameters so I can transfer from a drilled hole to a similar part and find the centres without having to accurately measure. The transfer screws are ace! little screws that fit different metric threaded holes and have a small centre punch that again can transfer to another part without having to measure. So good! unfortunately, my milling attachment still does not have the range for me to do all 4 holes with it mounted only once. I’m going to have to dwell on that as moving the part is time consuming and annoying.

3. I also spent some time hacking away at rhododendron and after many hours and sore limbs I have a new trail that forms a figure of 8 and keeps things interesting. Rhododendron is the Devil’s own plant though, it entangles everything and is irritant to skin and eyes. The leaves also seem to make the soil extremely slippery so I’m glad to be rid of at least a few hundred cubic feet of the crap.

4. A tool for removing the lock ring on 9point8 dropper posts. Read around servicing these posts (rarely needed and easy to do) and the one step folk complain about is removing the lock ring to get at the seal to grease it. I have used the work stand clamp to grip the part (it has no flats or other means to undo) but my Efficient Velo Tools Right Hand clamp is lined with leather and it doesn’t do it any favours. So, I made a tool to do it instead. First I shaped a delrin sheet, then drilled a hole and bored out a circle *just* smaller than the diameter of the lock ring. I then made a simple threaded handle part that compresses the delrin onto the lock ring and makes it easy peasy to remove. Next, I will counter sink the handles, and screw the delrin parts to them. I’ll also round the handles off and coat them in some sort of rubbery stuff so if (when?) I drop them it won’t take a chunk out of my frame.





Decaleur.

15 12 2019

I’ve been messing around with different concepts of how to mount a bar harness in the most rigid way possible lately. It’s easy of you use a Jones Loop bar of course, you have rock solid mounting with the bar and the forward ‘loop’. I emulated this using a Bar Yak Ultra on another bike I use with a less swept/wider bar lately.

But the idea kept turning around in my brain. Research on the randonneur style decaleur bag ‘offset’ got me thinking. Could I use the stem faceplate to make something similar? Of course, Rick Hunter made a Mac daddy version using a Paul stem and They are sweet as.

Then I remembered the Syntace TwinFix stem parts. This allows lights, computers or even your phone to be mounted using alternative stem faceplates, with an M5 threaded part, perpendicular to the face plate bolts. They say the phone mounting plate could in theory take 25kg, so I figured a roll bag with a sleeping bag and bivi sack at around 1kg would be no issue. All I needed was an adaptor, perhaps to use a Strap Deck.

 

Today, I got busy and made the part. It took a few hours of cutting, milling, tapping and finishing, but it works well. It needs evaluated in the field, but I reckon it’s a goer. Total added weight is around 80g including the Strap Deck, but not the Voile Straps or bag. But that is LIGHT and its rock solid.

If it works out, it will be for sale soon.





On bar angle, width and hand position.

12 11 2019

Recently I have been messing around with different handlebars. For years I have used Jones Loop bars exclusively.

From the first time I put them on a bike, swapping out my custom bent Seven 11° ti flat bars, I knew that they were awesome. I have no doubt I will always have Jones bars in use, particularly in the carbon version – light, forgiving and strong. They also have more grip positions for those long rides and the forward loop is excellent for additional bar mounted objects or handlebar harnesses.

The other strange thing about Jones bars, with the 45° sweep, is they seem wider than they actually are – a boon for tight, woodsy riding.

Over the years, however, I have used many different handlebar set ups in an effort to learn what I can in terms of comfort, effect on hand position and control in technical riding situations.

The most difficult, for me, has been drop bars. No matter how much I tired, I could not get in a good position on trad drops or even a rare set of WTB off road drops I owned briefly.

Early on, I knew that ti bars offered excellent flex to take some of the buzz out of the terrain – useful when you like rigid bikes and long rides. As mentioned, one of my favourite handlebars aesthetically and in terms of ‘softness’ was a Seven cycles ti in 11° around 660mm wide iirc. Crazy how we managed with bars like that. Of course, that was pre Jones bars and the added sweep definitely changed things for me. But I never stopped experimenting.

Later came a steel Groovy Luv Handle – great shape, but the steel was less forgiving – and soon after another custom Seven bar with 21° bend in ~710mm ish width if memory serves. The pure rearward sweep of that bar was difficult as stem length would have needed to be increased to make it fit correctly.

I found that a little strange – if you have tried several different bar sweeps, and overlaid them, or even use the fantastic ‘What Bars‘ site, you would be forgiven for thinking if you get the middle of the grip section in roughly the same airspace, you will be in the ball park for fit. Well, it doest seem to work like that. The orientation off the hand changes how you align your elbows and shoulders and the change in x, y and z in space is also extremely noticeable. Jones bars for example are best from flat to around 15° down slope towards the rear axle, but other bars may be best flat to swept upwards. Trial and error is important here.

So a Watson Cycles Parkarino was the next bar – a wide (720mm!) 31° sweep bar and if this had more grip space, I think it would have led me in a different direction. I had become used to the 160+mm grip lengths on Jones bars and even longer as they stretched to 710mm width. The Parkarino just had too little grip area for comfort. I am not sure Watson cycles is still trading…

For years, I then again used Jones bars exclusively, but a project that is on the go got me thinking again about different bars.

These days it is impossible to ignore the bigger fork, slack head angle, longer front centre, short stem, wider bar set ups. Key for control in these situations is how all the pieces come together – the leverage over the front wheel at speed is important but also the body position in resisting hard impacts. Wide, flat-ish bars and short stems put weight far behind the front axle and the width – a longer lever – offsets the shorter stem and greater trail.

I have never felt any issue using Jones bars, in technical riding and the rearward sweep keeps your weight well back when needed. However, it bears a closer look.

So, that being said, I bought a Salsa cycles Bend Deluxe – 750mm 17° and gave them a try on a couple of bikes. The 17° felt very ‘elbows out’ to me and the harshness of the aluminium was – well, harsh. But it got me thinking. Despite the negatives and ‘position shock’ I wanted to know more. Strangely, the thing I thought would be most noticeable (the width) was not. The Jones 40mm less width was indiscernible. Hmmm…

Next up with the help of some Control Tech Terminator I extended the Parkarino’s to 760mm wide, critically in the grip length, and put them on the bike. The ti flex was back and the width and bend was pretty good!

That led to a call to Rody at Groovy and a set of 765mm Luv Handles in ti were purchased – such amazing workmanship! 275g of comfort and control.

Then soon after I contacted James at Black Sheep to enquire after a set of 787mm, 25° custom ‘Flatter’ bars. My most ridden bikes now have considerably wider bars with 21-25° of sweep and I admit I like them a lot.

I have shortened the stem on one of the bikes – from 80mm to 70mm – and I am not sure I like that move. As noted above, the rise, or x,y,z position is not easily predictable in terms of what will feel right and another grouch is the stem length options. Stems are almost universally shorter than they used to be (35-80mm as opposed to the 100-150mm tillers we used to use). That means a 10mm change is a much bigger percentage of difference when compared to a 10mm change in a much longer stem. My view is that stems should be available in at least 5mm increments.

Syntace do offer a 75mm stem option suitable for 800mm bars and I have one waiting to fit.

The latest bar I have my hands on is a Meriwether double bend Sweeper bar (with shimzilla) with ~21° bend and 800mm width. I’ll report back once I have some time on them.

My conclusion is that if you do like more sweep in your handlebar, but don’t want to give up on width, there are a lot of options these days with excellent  buzz control that allow a wide option for the ‘new school’ geometry that is becoming more popular.

As to how this all goes together with stem length, that is another post…

 

 





Mullet: part 2

4 11 2019

After deciding that a mullet (reverse mullet, really) was the way forward for a rigid bike, I started talking to Sean at Vertigo Cycles. He knows me and my riding style well by now and with a few simple questions produced a blue print for a sweet looking bike. I knew before even swinging a leg over, it was going to be awesome.

And so it is.

From the dialled geometry to the sano dropper rooting, internal DI2 and tight tight tight construction, this bike is a pure expression of what a rigid mountain bike should be.

As swift as it is through the winding trails in the trees, it will take flight with aplomb and also be a relaxed multi-hour mile muncher. When called upon, the short rear end and on-point steering geometry, will allow rough and technical trail to be cleared with no drama. It is light, solid and an absolute dream of a bike.

Do I have any more answers about why the set up works so well? not really. My gut feeling is the lower rear axle when compared to the front, combined with the short rear centre, means the rear wheel tucks in and under the front’s turning radius. There is also something about the reduced rear wheel radius on step downs and rocky section. For some reason, the back end feels like it has less amplitude in rough terrain. This, along with the dropper, means you never feel like you will be launched.

All the while, the front wheel’s diameter and cush offers amazing roll over, smoothing out chatter and refusing to drop into holes in the trail.

Over the last few weeks I have ridden the bike back to back with its twin, set up with a suspension fork at 130mm travel and 27.5+ wheels f+r. Differences? yup!

They are both amazing. I have always loved rigid bikes, but there is no getting away from the fact that a suspension fork when set up well is a get out of jail card. It can save your ass when you have stepped over the control line.

 
One is not better than the other…they are sweet as!





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.





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 über 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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