WTB Trailblazer 2.8: 27.5+ revolution?

20 10 2014

Despite some folk bemoaning the introduction of yet another tyre size, the 27.5+ makes all sorts of sense.

For starters, a 27.5×2.8 tyre such as this one, the WTB Trailblazer, fits in the rear of a 29″er that has reasonable clearance. “So what?” I hear you cry. Width on my 35mm Velocity rim (tubeless) is 68mm and the diameter is 726mm – in other words, a wee bit less than a full blown 29″er, in order to keep the widest point of the tyre further back in the chainstays.

[NB: I had previously noted the diameter as ‘right around 735mm’ – after a prompt from Michael, see comments, I measured this accurately and the diameter at 14psi on the 35mm velocity rim, tubeless is 726mm…it just goes to show, always measure yourself if you want to be sure! – thanks Michael].

The benefit is you get some of the advantages of a semi-fat tyre (improved traction, lower pressure, better ‘float’) without having to get all weird building a custom bike with a yoke or fat-bike wide bottom bracket and rear hub: it should slot into many 29″er frames with minimal fuss. The only thing to consider is a slight drop in BB and slackening of angles if only the rear is retrofitted.

My suspicion is that there will be several 27.5+ tyres along forthwith and my guess is they will in some cases be larger than the Trailblazer from WTB, in some cases the same. Rumour is that the Vee 27.5+ tyre (the Trax Fatty) is a full 75mm+ wide and will not fit most 29″er frames. There are whispers of Bontrager and Panaracer 27.5+ tyres and another WTB in the pipeline too.

How does it ride?

Really well. Much better edge than a Knard and it gives up little in terms of the float/low pressure (I was running it at 14 psi and will probably drop it one or two). I was riding in slop today and I hardly ever lost traction despite the centre ridge being almost complete and the other knobs being not that burly. You don’t get the insane roll-over-ability of the huge 29+ wheels (which are near 775mm in diameter), but the low pressure helps maintain progress in rocky, chunky terrain. The compound seems good – minimal slip on wet, mossy rock and roots. and the tubless set up was a treat – TCS is good. It is not über light at 950 and some grams, but the sidewall is solid which is a good thing.

More time is required to see where this is going, but I like it so far. Most folk are going to comapare these to fat bikes and 29+ knards, I suppose, and I think that comparison leaves the Trailblazer in a favourable light.

As WTB say: Big Kid Shreddin’ / Plus Sized Grinnin’

As an aside. I set up the Velocity 35mm rim with a bead seat shelf augmented with a Gorilla tape lip after a discussion with davechopoptions. It worked surprisingly well…and we will see if prevents burps.

…and after a final layer of tape…you can just make out the extra ridge…

One-up 40 tooth sprocket and RAD cage.

19 10 2014

When I was looking at doing the Highland Trail Race earlier this year, I was slightly concerned that my usual 1×10 set up would not have a low enough gear to cope with the combination of very tired legs, steep hills and a loaded bike. I looked at using a 30 tooth chainring, but felt this would diminish the gear range detrimentally.

At that point I became aware of the release of the RAD cage, by One-up components. The purpose of this is simple: it changes the way the upper jockey wheel moves in relationship to the rear freehub cluster. Why? you can adjust a traditional derailleur to cover a broader range of rear sprockets, primarily by increasing B tension, this creates enough clearance for a 40 or even 42 tooth sprocket. However, this compromises the jockey wheel’s tracking of the sprockets, particularly in the higher gears (smaller sprockets). In essence, shifting suffers as the upper jockey wheel is far in excess of the suggested 6-8mm from the sprocket.

The RAD cage is well made and following the video instructions for installation makes the process extremely easy.

A few months ago, I fitted a 40 tooth large sprocket and the provided 16 tooth sprocket that replaces the 15 and the 17 tooth sprockets in the original cluster (you must remove one in order to make room on the freehub body for the extra 40 tooth sprocket). I use a Wolftooth 32 tooth chainring, with an XT donor cluster and XT rear mid-cage derailleur. I decided on the 40 tooth rather than the 42 because I felt this would give the derailleur a little less of a hard time and it is also the same range as the new XTR that I am quite keen to use in the future.

I have a few hundred miles on the system now using the provided One-up 16 tooth replacement sprocket and then an aftermarket XT 10 speed 16 tooth sprocket*. The gear range has changed from 11-13-15-17-19-21-24-28-32-36 to 11-13-16-19-21-24-28-32-36-40. Unfortunately, the 15-17-19 area is where I spend a lot of time and I was concerned I would feel I was not in the right gear too often. It is true that I do feel the increased jump between ratios, but not badly enough to take away from the huge boon the 32-40 ratio is. You can climb walls, even loaded, with this gear ratio.

Shifting: the shifting has been a mixed bag. The ramps on the provided 16 tooth ring seem (to me at least) to be in an unusual orientation. The part has 2 fitting positions: one for SRAM and one for Shimano. I initially used the Shimano position and noticed a lag of around a second of chirping before an up shift was achieved. There was also a lag on the down shift. When I fitted the part, it was clear the SRAM position was much closer to keep the ramps on the sprockets in line, but I decided to follow the instructions to the letter. On refitting in the SRAM orientation, things improved but there was still a lag that bugged me.

I then fitted a *Shimano 16 tooth sprocket and with this, although not exactly in line, the ramps were really closely aligned indeed. Shifting quality is now almost at original ‘Shimano perfection’ levels. I think the detailed tooth profiling aids up shifts to higher gears and the ramps being in line helps the down shifts. Don’t get me wrong, the supplied One-up 16 tooth is good, but Shimano carry a big stick when it comes to shifting performance. This is something I would recommend if you go for this system with a Shimano set up – I cannot comment on the SRAM performance.

Longevity: you *can* see wear on the 40 tooth sprocket (it is anodised black aluminium as opposed to the steel of the original Shimano set up) but there has been no drop in performance.

All in all, I am extremely happy with this set up. Things I would like to try: a short cage RAD cage for the Saint derailleurs I love. I have no idea if this would provide enough chain gathering to let the system work, but I can dream.

All in all, I would say this system merits 8 out of 10. If longevity remains good as we come into winter that would be 9/10. Improved 16 tooth sprocket would give it a near perfect score: as a hop-up kit to provide increased gear range, with the accepted change in the jumps between ratios, it does exactly what you want it to do and it does it very well indeed.

Two trips to Aviemore.

7 09 2014

Ugh! where does all the time go, eh? I have a huge backlog of things to say, from trips, rides and messing around with various bike parts to a review of the Mountain Laurel Design Cricket tent. I try to keep things in chronological order and no doubt as the skies darken and the winds and rains come, there will be plenty of time for blogging. Now, however, the sky is blue, the sun is still warm and I am enjoying being outside as much as possible – solo and with my family. All good.

A while ago now I had two different trips to Aviemore. For the first, I had a plan to clover leaf several rides from a base at the Rothiemurchas campsite. After arriving in the middle of the day, I wanted to take advantage of the warm sun and long day to head north on the Dava Way, essentially heading through the Ryvoan pass, then following (for the most part) an old rail line, to the coast at Forres. A blog I follow, Topofests, had described some sweet looking singletrack along side the river Findhorn. Unfortunately, I left too late in the day to cover the distance and see this. Another time.

My hombre Chris joined me for the next couple of rides. After the initial climb of the Burma road, we had a great time taking in this classic loop, but threw a curve in at the end and headed out to Burnside, railing some of the tight, woodsy singletrack. Awesome!

That left a classic Morlich/Badaguish loop for the last day – those trails always deliver a broad grin and are as challenging as you want them to be.

The next trip to Aviemore, a few weeks later, was with intentions of an evening preamble to find a decent camp, somewhere in the trees, followed by a big mountain ride the next day. The bags were packed and strapped to the bike, but the weather refused to play ball. The rain was sheeting down. Hardly conducive. Fortunately, I found a space at the Old Bridge Inn bunkhouse and planned a loop for the next day, up towards Ben Macdui, then round to Cairn Gorm and studied the topography of the various ridges and potential ways down over a fine meal and a dram.

The initial climb across Coire an Lochain and up onto the shoulder of Cairn Lochain started in fine weather, but became punctuated by squalls of rain and low cloud. It was clear the wind was strong but once I was up onto the plateau, 60kph sustained wind made the sleety rain sting and a ride around the cliffs edge towards Cairn Gorm a perilous proposition. With tail tucked firmly between my legs, I enjoyed the descent and the weather was far better below cloud level. I headed over to Abernethy forest instead, revelling in the warmth amongst the caledonian pine forest.

Nothing ventured, nothing gained – but sometime soon, I’d like to get that loop done.

Wheel build: a photo essay.

19 07 2014

With thanks to Sean for the advice on building with the new style nipples and the nipple tool. The old aluminium Pillar nipples were rotting with the ammonia from some sealants escaping through the porous gorilla tape, so Enve updated to a flat surfaced brass nipple.


19 07 2014

After the rugged beauty of Skye, I turned my attention to an old friend – Torridon. As I have mentioned before, Torridon is an awe inspiring place to ride. The terrain is rugged and technical, but the trails drain superbly, for the most part, and offer good grip: a useful characteristic as they can be steep and consequential.

I wanted to extend the usual Annat/Achnashellach/Coire Lair loop so after climbing from Coulags and descending the awesome trail to Annat, I took the road west towards the Ben Damph estate.

Incidentally, on the descent, I chatted to Alasdair McLean, who was on his way to completing the Highland Trail 550. I had pulled out of this a few weeks prior and it caused a twinge of regret to talk over his experiences. He was clearly tired but in very good spirits. I wished him well and continued down the trail.

After taking the excellent estate track south into the hills, there was an exceptionally wet singletrack alongside Loch Damh to the turn around at Kinloch Damph. Here, the trail climbs gradually, onto the shoulder of Beinn Damh, before descending from Coire Roill back to the coast.

It really wasn’t until the final few kilometers that this additional loop became worthwhile and I am not sure I can recommend it.

I had met a few other riders taking part in the HTR 550 the day prior at Strathcarron Station, including Alan Goldsmith. Alan had warned me off my previous plan of taking the trail up Coire Mhich Nòbuil behind Liathach, before descending Coire Dubh Mòr, back towards Loch Clair. As he explained it, he likes a good hike-a-bike, but the route in question was hideous. Fair enough!

I had been wondering about overnighting: climbing to Loch Coire Mhic Fhearchair and (hopefully) sleeping above the midge ceiling before contining around to Loch Maree, or perhaps Fisherfield, but this will have to be another time.

After Ben Damph, I climbed back up the road from Annat, to Loch Clair and from there up the beautiful trail past the Easan Dorcha bothy.

From here, I descended the Coire Lair trail – perhaps the best trail in Scotland. A few hours later, I was sat in the Plockton Inn enjoying a seafood platter and a locally brewed pint. You can’t beat that.


19 07 2014

A while ago now, I had a few days riding on the Isle of Skye and in Torridon. This instalment will show some of the trails I rode on Skye. Despite the weather being kind enough, some of the trails were very wet, even under water, but you take what you get on Skye: the weather is often as challenging as the terrain on the Inner Hebrides.

As boggy as the initial part of the 50km loop on Skye was, the views of the Cuillin ridge and the superb trail higher up in the mountains, more than made up for it.


The descent down to Sligachan, mild in gradient, was one of the better trails I have had the pleasure of riding.

Next up, Torridon.

Breaking news.

19 07 2014

Rather unfortunately, after 2 hours of use, the Thomson dropper doesn’t seem to want to return to full height anymore. You have to give it a pull and there seems to be very little pressure in there. I suspect a nitrogen leak (the hydraulic cartridge relies on a nitrogen charged spring in the Thomson: it is not user serviceable). I suspect I probably jinxed myself by vocalising the fact I had waited for a good few years for these devices to demonstrate reasonable longevity. Anyhoo. Back to the shop and we’ll see what happens.

So just to cement my position as a paying beta tester, I got this to mess about with…

The 44 is getting lower gears. I do ok with 32 – 11-36, but there is no doubt that when loaded, with those big and relatively heavy tyres, it can be hard work. So…we’ll see.


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