Westworld.

8 11 2016

A little while ago now, it became clear things were afoot on the West Highland Way, with trail construction beginning near the edge of Loch Lomond, north of Rowardennan.

Three years later and it would appear the work is complete.

I used to ride the West Highland Way fairly often: it was Scotland’s first ‘made’ long distance walking route, stretching 96 miles from Milngavie to Fort William, passing some stunning West Coast scenery on the way. Around 80,000 walkers use the route yearly, concentrated in the summer months and for this reason, biking on the route is best out of season.

So I found myself trundling up from Balmaha the other day in glorious sunshine – although there was a serious nip to the northerly head wind – and on climbing past the Lodge at Rowardennan, found the left turn onto the new section.

Immediately, it became clear the plan was to emulate the singletrack, which is so festooned with natural features, that makes the section from Rowchoish north to Inversnaid sublime.

In saying that, they turned the dial up to 11.

Rock steps, rock step gaps over plunging water run offs, narrow and super steep wooden staircases, fallen tree up-overs, narrow gaps through sharp rocks and edge-of-the-loch trail all combined to leave me wondering if I enjoyed it or not.

I returned by the high route, giving me time to reflect. Yes, I enjoyed it but it is a serious undertaking, requiring skill, balance and confidence to tackle on a bike. To combine it into the whole route – particularly loaded – would need a serious amount of beard stroking.

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The section i rode was 3.5 hrs. Do click for bigger pics and there are a few more on my flickr. I didn’t catch most of the techy sections as it was hard enough to do once, let alone scope for a pic…





The wheel deal.

22 06 2016

Well, I thought I’d share this set of images.

This is the Bontrager Barbegazi, at 20psi, on a Nextie 65mm external rim – 27.5×4.5 (770mm diameter and 115mm casing width, a few more knob to knob).

That’s big.

Compare to a fairly normal 29×2.2 MTN King.

Now, it is next to a Bontrager Chupacabra 29×3 (765mm diameter iirc).

Perhaps most interesting…next to a 26×4.5 Flowbeist (somethign like 745mm diameter – I think! might be 750mm)

As predicted, the Vertigo cycles fatty is a hoot with a 29+ front/27.5+ rear. I actually think it might be bad for my health. Just today alone, I crashed 3 times. Not because I lost traction, more because I was tackling obstacles at a greater speed than I am used to. As a result, I was landing closer to stumps, trees and other immovable objects than I am used to. Sometimes, too close! Interesting.

My curiosity will get the better of me though – I will pull the rear Chronicle in order to mount a Hodag so the bike will be more balanced when I put that Barbegazi on the front.

Oddly, the tape I use (3M 764) failed the first time I mounted the Barbegazi. The tape is 50mm wide so I did one wrap and then dry mounted the tyre, as I usually do, before addign sealant. In this case, the bead seemed to grab the tape on both sides and drag it apart, tearing it down the middle. I re-did it with a little sealant to lube the bead’s passage up the rim into the bead socket and it was golden. Live and learn.





Differential.

12 06 2016

I’ve been messing around with different sized wheels on the Jones for a while now. It has settled on a 27.5×3.8 (nearer 3.5 in reality) front and a 27.×2.8 rear. I like how a slightly bigger front wheel gives good roll over and a smaller rear seems to stay ‘tucked in’ and agile in the tight stuff.

My Vertigo Cycles fat bike has now got a new set of wheels as well. The front is a 29×3 and the rear is a 27.5×3.

The front wheel I have had for a while, shod with a Chupacabra; the rear with a 27.5 Chronicle complements it very well.

The build was as follows: Nextie Junglefox 2, with Sapim D light spokes, DT aluminium nipples and a DT swiss big ride 197 hub.

I followed the advice of Wheel Fanatyk and used beeswax to lube the nipple/rim interface. It worked very well indeed. The nipples are pro lock.

Tensioning was a bit of a mixed bag, it wasn’t quite as smooth as I had hoped and there is more than 10% variation on a couple of the spokes. Perhaps this was because I went with 2 cross due to the extreme bracing angle of the super wide hub and the stiff carbon rim. It seemed to tension very late and suddenly.

In retrospect, I might have gone 3 cross as this would lessen the angle of the nipple at the rim.

That or perhaps I should have used the pro head DT nipples, that are more spherical shaped and thus sit at extreme angles more easily.

I have a couple of hours on it. It seems to be fast, the rear doesn’t particularly feel smaller than the front in terms of roll over, but the bike as a whole is very manoeuvrable. The front is kicked back a touch and feels to have slightly light steering input. It gained a cm in height with the bigger radius over the Flowbeist.

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This wheel change is temporary to further evaluate the mixed wheel size: in time it will be mounted with a 3.8 Hodag rear and 4.5 Barbegazi front, which should be less of a differential.





Base building.

8 06 2016

The time I might spend driving to a new or more interesting destination is sometimes better spent rolling miles from the door.

So it was as I headed out along the West Highland Way, yet again, on another sunny day.

The walkers were starting to gather to amble the long, meandering route to Fort William and it led to some polite hellos before I turned at Garadbhan to take the sealed (ish) road towards Aberfoyle and then through Queen Elizabeth forest, but instead of the usual ‘mangrunt‘ extension to Inversnaid, I climbed, skirting rainclouds and goats at Comer, around the back of Ben Lomond.

The view to the Arrochar Alps and the Cobbler was amazing – too much for my meagre camera skills and the decent down to Loch Lomond side was as steep as I remembered.

It is always a pleasure to ride the techy trail on the edge of this bonny loch and so it was that day.

Returning via the cycle path from Milton of Buchanan to Drymen then rejoining the WHW to head for home. I worked out the mileage and knew the time accrued, but I have forgotten. Money in the bank/miles in the legs and yet another dry-trail ride.

Next up, a bikepacking trip of a relaxed nature, using a new, superlight bivi.

I also have a load of bits and bobs to do – including an inspection of a 9point8 Fall Line dropper post, which is to be used on a new bike build soon, some wheel building action involving beeswax and a 27.5+ Chronicle and 27.5+ Ikon. More soon.





Time to ride.

23 01 2016

Sloppy, slimy and slick. Thick mud and treacherous rocks. Teflon coated roots. It is winter, after all.

The hodag needed very little time to find it’s way to my heart. It rides lighter than it would seem. Feels kinda sporty-like. It replaced a chupacabra on a nextie 50mm rim so the weight gain is in the region of 360g or so. I never felt like I was struggling with the girth though. And the grip…oh the grip!

Those sipes and spaced out blocky tread make for a very secure front tyre. Granted, with a 45mm internal rim, the profile is round, but at 9psi I had bite everywhere I needed it.

The diameter is 20 mm or so less than the chupa. It *was* noticeable. The roll over a 29+ has is a boon. I missed it in some places. But the chupa struggles in mud…not so much on slick surfaces: the compound is great and offers security.

The hodag clears well and keeps coming back for more. It did not fold under and I suspect I will end up lowering the pressure a touch just to see how it feels, though it absorbed chatter and square edges with aplomb.

Yeah, like it.





Hodag.

31 12 2015

So, the Bontrager Hodag. B plus plus? 27.5×3.8″ or about 93mm wide on a 50mm rim it seems. Diameter around 750mm or so (I *think* these are Walt Works measurements, but cannot be 100% certain, as I committed the numbers to memory, then promptly forgot the source).

I received the tyre the other day and decided that I would use a Nextie rim to build up the wheel: in this case a ‘new’ Jungle Fox II. I used a Jungle Fox previously, but the new one is 2mm wider at 52mm wide external, 45mm internal. This suggests a couple of extra layers of carbon sheet, as the bead edge is thicker. Probably a good thing, but they are still light for such a big rim. My previous experience with Nextie was slightly marred by the nipple drilling being off in several cases. Not enough to make the wheel impossible to build, but the longevity will definitely be affected. In saying that, the rims have seemed durable in use over the last 10 months – see my previous post for the first build with Nextie rims. Also, there are rumours they are using a different manufacturer and the drilling has been much more consistent recently.

Nevertheless, due to my prior experience, I am going to use a DT Squorx pro head nipple, that has a spherical interface with the rim hole edge, hopefully allowing a better alignment with the hub if any of the drilling is off. In addition, the Squorx head will allow for a safety net to let me tension the spokes if needed (poor drilling angle adds significant resistance to tightening the nipples during the build).

I am using Sapim D light spokes, 2 cross in this case. The hub is a Paul wHub, which is symmetrical with relatively high flanges and wide spacing; there is just no need for 3 cross here.

I used Freespoke for the lengths after measuring the ERD (as slightly larger than the 533 quoted on the website, which I suspect is the actual rim inner surface diameter). Freespoke has proven very accurate over the years: highly recommended.

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More as the rest of the wheel parts arrive.





No pressure.

25 09 2015

A recent mtbr thread (I know, I know…) got me thinking…

Here is my input on a thread about ‘plus’ tyres…

“So I got to thinking about this a bit more. I dont know too much about the physics, but I do know I like the combination of a higher volume tyre at lower pressure for my relatively low speed, reasonable tech riding on a hardtail or rigid bike.

Why is that?

Considerations for tyres (and/or wheels):

Comfort
Control/traction
Rolling resistance
Puncture resistance
Rim durability
Weight

My thoughts:

a) Lower pressure = more comfort given the same casing construction

b) A bigger volume tyre feels similar to a small volume tyre at less pressure (pounds per square inch…I guess it is self explanatory) given similar casing

c) Less aggressive tread gives less rolling resistance given the same casing construction and size (I don’t know how true, but for rolling resistance of pick up truck tyres, 60-70% is often associated with the tread design)

d) Increased hysteresis can lead to increased rolling resistance (‘tacky’ DH tyres anyone?)

e) Increased hysteresis gives more traction (‘tacky’ DH tyres anyone?)

f) Less tyre pressure is unlikely to make you slower (increase rolling reistance) given the range that is realistic for bikes. It is also, probably, unlikely to make you faster if considered in isolation

g) Bigger volume tyres create a bigger foot print in general, though pressure and casing design affects this

h) Bigger foot print is associated with more traction

i) Lower pressure tyres can lead to pinch flats with tubes, and rim strikes

j) Casing design can be beefed up (specifically on the sidewall) to mitigate this, but then the tyre becomes less supple – see hysteresis

k) Casing design can reduce or promote sidewall wear and piercing type puncture risk

So: a bigger tyre volume, with a lower pressure, and less aggressive tread might provide similar or better traction than a smaller, narrower tyre.

It might roll at the same speed (or perhaps faster if the tread allows) and it might be more comfortable.

If it is made well – with good quality casing – it might not wear fast or be at risk from punctures and it might not be too heavy.

Given the whole light strong cheap triumvirate, it is unlikely to be inexpensive.

Depending on how you load the tyre this may be a *good thing*. If it is more likely to flop around on the rim (too narrow a rim, or just high bulbosity) and is used in a high speed/direction changing terrain, it might feel more vague. This is probably why enduro racers/DHers are using no more than 2.5” tyres I suspect.

I guess that, in a nutshell, is why I like ’em?

Now – I am no expert – this was purely typed as a vague self assessment. I’d love to hear if anyone else has any thoughts on all this.”