Saturday, March 2, 2013

D.I.Y. SkiBike On A Budget

I had been itching to build a second skibike for at least a year, the plan being to be able to offer anyone the chance to join me for some guided skibiking. What I didn't have, was unlimited time or money at my disposal. So let me make myself clear, this article won't be about a ghetto skibike costing pennies, nor will it be about the sort of machine for an expert who wants to make 30' cliff drops. This article will be about making something that will look good, perform well and most importantly, not fall apart miles from base camp. I anticipated the cost would be around £500, so let's see if I could build it for that amount.

So, where to start?

Donor Frame - £65

For the money you will have to consider either new "bankrupt stock" or an older second hand, good quality frame or even complete bike from eBay. Mine was to be the same vintage Marin East Peak frame that I first bought and converted back in 2009

Powder coating of above - £40

If you opt for a tatty second hand frame, then powder coating is a must. I am no snob, but appearances really count in a resort environment, why? Turn up with a shabby skibike and if you are allowed to use the lifts, your cards will be marked from the offset. Raise the attention of the management with one big crash and you may find yourself refused access; worse still the next skibiker might be turned away too. Spray paint lacks the durability to withstand the many knocks and scratches that skibikes are subject to, hence powder coating is your best choice.

Spray paint lacks durability - powder coating is your best choice

My rear triangle was very chipped, I opted for a blast and refinish in glossy skibiker black to match the forks I had chosen. The result was spectacular, but I made the error of removing the bearings, but not putting something in their place as a mask. As a result, I had to spent a tedious couple of hours sanding away the powder coat to be able to refit the bearings, bummer.
The main part of the frame was clear lacquer over brushed aluminium, it still looked tidy, so I simply removed the decals to make it look a bit less like a production bike.

Ski Mounts - £220

There are plenty of people who can knock something up out of angle iron and old skateboard trucks, but with kits available from BikerMads or AlpineSkiBikes for a shade over £200, it's not worth the time messing about. Furthermore, in France, some adapter kits have been given type approval homologation, allowing their use on the lift systems just like factory produced skibikes. I fitted the SkiXBike adapters as the price is slightly better when you take the final cost including; EU import duties, handling fees and VAT into account.


SkiXBike adapters - a shade over £200


Skis - £99

What! SnowBlades can be sourced in the summer months for about £50, but for a little bit more you are likely to find something with a wooden core. Wood core skis are considered much more durable for the dynamics of skibiking, especially the loads that the front ski is subject too. The last thing you want to do is snap a ski half way down the red run at the end of the day.
I fitted Head "Big Easy" 95cm skiboards, which have a good track record for use on skibikes.


Head "Big Easy" 95cm skiboards


Forks - £70

Keith Bontrager's often quoted aphorism; "Strong. Light. Cheap. Pick Two." holds true on a tight budget. What I would aim for, is strong but heavy for this price, expect about 4" of travel, not a huge amount by modern standards, but enough for on piste and gentle off piste excursions.
I opted for the Suntour XCR forks, one model up from the Suntour XCM forks used on the Black Mountain Snowscoot. They have knobs to adjust pre-load and dampening, but I think they are more for show than go. This is the second pair I have bought and I know from previous seasons that they can withstand the cold reliably.


Suntour XCR forks - basic, but can withstand the cold reliably.


Rear Shock - £30

You can forget Fox or even Manitou at this price point. What you will get is something from the far east with a spring and possibly some form of dampening, one the plus side the spring should still be up to the job and can be quickly swapped out to suit your body weight. Avoid cross-country type air shocks, at freezing temperatures the seals are prone to sudden failure, once that happens you go from "full sus" to "hard tail" in the blink of an eye. Unfortunately for me, the 165mm length, eye to eye, shocks to match my frame are becoming very scarce and I simply refuse to pay the same amount for a tiny suspension unit as I would pay to put 4 springs on my car. My only option, with time running out before departure day, was an undamped unit, more on this at the end.


165mm eye to eye shocks are becoming very scarce


Saddle - £10

Forget fancy racing saddles here, what you are looking for is a chunky bit of padding to stop you getting intimately acquainted with the frame or the seat post. Most intermediate level skibike riders spend as much time on the pegs as sat down. The cheapo supermarket own brand "comfort" saddle is ideal, robust enough to last a few weeks and dirt cheap to replace if it fails.

HandleBars- £20

You don't need to get carried away, but seek a known brand name with a brace bar. I was able to get Marin's own brand for this price, the brace is a handy place to attach the safety leash for use on chairlifts.

Stem Raiser or Adjustable Stem - £20

These are very handy items to "dial in" the skibike to your requirements. As a rule of thumb a skibike is better balanced with the handle bars much higher and with much less reach than the equivalent wheeled frame. Get this wrong and the front ski becomes very difficult to control with dire results. I fitted a Raleigh adjustable stem and set it to 55 degrees and the minimum of reach. This put the handle bars at a height that I found comfortable, but with much less reach than I had become accustomed to. It actually worked really well and I never changed it.


Raleigh adjustable stem - putting the handle bars at a comfortable height


Lock on grips - £20

Most metals shrink as they get colder, condensation that forms on cold metal acts as a fine lubricant. Put these two facts together and the rubber hand grips which appeared to be welded in place back in the workshop, easily come loose whilst out on the snow. Make a sudden turn and the grip remains in your hand whilst the handlebars go their own sweet way.
Lock on grips are the solution to this dilemma, I found the ODI ones to be excellent, for this project I used GT, which weren't quite so good, but did the job.

Miscellaneous fixtures and fittings - £30

The little things like a safety leash, stainless bolts and the anti-dive preventer for the rear ski,don't cost much, but the total can ramp up.
I made up an anti-dive link from some welded chain, then ran it through some plastic flexi pipe, which prevents it from sagging when not under load. I incorporated a D shackle link to make for quick mounting and two O-rings which gave a bit of compliance and reduced the tendency for the link to snatch going over bumps.
I make the safety leash out of two of the shoulder straps used on small carry bags joined together with a split ring. An inexpensive jumbo carabiner goes on one end and can be snapped onto the handlebar brace when required.


Anti-dive link fabricated from welded chain


Sum Total of the Above £624

The last item to consider is the time you need to put into assembly, after all, it is the single item that none of us know how much we have left.
To mount the skis to the adapters, fabricate the rear ski anti-dive link and assemble the various components would take me about 8 hours. I am getting quicker with every skibike I build, but I am not a quick worker.

Evaluation & Testing

Testing is a strange feeling, often it goes like this; one day you have all these parts on your workshop floor, the next you have a fully assembled skibike and the day after you are standing on snow ready for the first run. You reach the top of the chairlift without knowing what will happen next; will the skibike ride like a dream or are you heading for a hellish, uncontrollable descent? Luckily, my first run wasn't hellish, but it wasn't pefect either.


Skibike test - my first run wasn't hellish, but it wasn't pefect either

The Head skis are; shorter, wider, more flexible and with a deeper sidecut than the Line skis I have become accustomed to. This gave the steering a buttery and soft feeling which worked well in deeper snow, but could lack bite on icier sections. I found it too easy to overpower the front ski, loose the front end and do the classic superman ejection with this combination. For next season I would like to mod all my front ski adapters to incorporate some form of axial travel limiter, such as the Lenz skibikes and even the new generation of Black Mountain Snow Scoots utilise.

I think the SkiXBike adapters are very slightly lower than the Alpine Skibikes design that they so closely emulate. They are well made, but some of the detailing, such as; the fit of the springs, washers and nuts are not quite as good as the original system.

The rear shock I used was only 160mm and not 165mm from eye to eye, you wouldn't think that 5mm could make much of a difference, but the effect is amplified at the end of the swing arm.
As a result this skibike sits about an Inch lower than my other skibike, the effect is negligible in a straight line but when leaning for turns it was noticeable that it was easier to catch the side of a boot on the snow and on some bumps the bottom bracket shell would crash through the snow.


Skibike test - the bottom bracket shell would crash through the snow


The SkiXBike adapters are supplied with a pair of BMX knurled pegs, the surface on these is as sharp as a rasp file when indoors, but get some snow on them and it fills up the troughs and turns to ice under foot pressure. Once this has happened you have absolutely no grip what so ever on the foot pegs, when riding in a straight line this is fine, but make a turn or stand on the pegs and your foot will fly off unpredictably. I had to ditch them after one ride and received a cracking offer for a pair of Alpine Skibikes foot pegs.

The first D-shackle fitted to the rear ski anti-dive link shook loose on a particularly hard and icy run at the start of day 2, luckily I had a spare in my pocket and that evening treated my stock of spare D-shackles to a dose of Loctite Blue thread locking compound. There were no further issues with lost links, in fact quite the opposite happened and I needed mole grips to release it one icy afternoon. I was expecting the O rings to snap at some point, but they took a huge amount of abuse and I found the progressive stretch to work really well at controlling the attitude of the rear ski, without any snatching from the anti-dive link.

The saddle rails on the £4 supermarket saddle were prone to bending under even modest loads, I am no heifer (80kg), but it happened to 2 identical saddles in single day on each. On the flip side, the saddle represented the same amount of money as one piste side eatery was asking for a small container of chips! In future, I shall go for something a little more robust for skibike use.


Cheap saddle failure - a false economy


Conclusion

The SkiXBike footpegs, rear spring/shock absorber and saddle fell below the standards required of a skibike for recreational touring around ski resorts. They were all parts that can be rapidly swapped out for more suitable items. None of my mods were calculated with great engineering precision, I simply follow the plug and chop school of backyard engineering.

I went over budget by over £100 or 20% and there are not many items I could have scrimped further on, in fact I should have spent a little more on the shock, at which point you might be able to buy a new SledgeHammer skibike for the same money. It would probably work just as well, if not better, but might be a tad heavier too. On the other hand in the Summer I can put the wheels, etc. back on my skibike and head off to where I choose and get full value from my investment.

At the risk of becoming tedious let me re-iterate what I said at the beginning of this article.
Yes, you can build something for peanuts if you have the time, skills and materials, but few people have the skills to build from scratch and not everyone enjoys it. I managed to build a working skibike for approximately £600, it suited drifting and skidding, more than carving, it was fun to ride and quite forgiving in nature.

Whatever you chose to build, has to perform well, ride safely and look good, failure is not an option. Good luck.

Looking for parts to build a skibike? Or perhaps one ready to ride away? See our Parts For Sale page here.

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