BTR Fabrications Pinner – Review
We’ve spent a couple of weeks riding BTR’s Pinner, a 140mm steel trail bike designed to sew up the “one bike” solution.
BTR started as two guys in a shed, Burf is a South African born son of a bike shop owner and Tam is a Scot from beyond Fort William brought together by fate in the South East of England. There they designed and made DH specific hardtails and turned a few heads with their down to earth approach to bike design. Since their early days they have grown their range and moved into a workshop at the legendary Bicycle Academy in Frome where they split their time between designing and making their own range and coaching for TBA.
The Pinner is billed as a “go anywhere trail destroyer”, the idea being that it is strong enough to handle the abuse of uplifts, ride all day up and down hill, or even ride a trail centre or two. 140mm is pretty standard at the shorter end of “Enduro” travel bikes, and a few of our favourite all day bikes feature that length of travel. I must admit to being a bit surprised when I found out the Pinner was a 140mm as it’s aesthetic lends itself to a longer travel. Indeed, the styling of the bike with a burly linkage and a Cane Creek double barrel remind me a bit of a DH bike. The skinny tubes scream “steel” – lucky really as the bike is made out of lovely steel. The tubes can be skinny thanks to the properties of steel, so while you might not have the sleek lines of hydroformed aluminium or carbon fibre you do have superb strength and that un-matchable springiness that comes with it. Look a little closer and the attention to detail is fantastic, the intricate bits of folding and gussetting are testament to the love that goes into these bikes.
In terms of features, as BTR will make your bike to order, the choice is yours, but essentially you can do pretty much anything! ISCG/05 chain guide mounts, routing for droppers and the option to tweak the geometry. The rear axle is 142x12mm and also features a replaceable mech hanger. The bike I’ve been riding has the standard geometry for the 275 wheel size, dropper post routing and no chain guide mounts as the builds that mags have been testing on have all been runnning wide-narrows and no guides. Personally we’d have specc’d the ISCG05 and run a little taco to keep chainrings safe, that said we’ve not bashed it yet! You also get a rather neat integrated seat-clamp as standard.
The geometry of the bike is pretty cunning, on the 275 wheeled bike the head angle is 65.5 which is nice and slack for trail attacking, but the seat angle comes in at 75.5 degrees, steeper than you would find on most bikes of this genre. What that allows you to do is run a nice low standover height and then launch the saddle up to stratospheric heights without putting yourself too far over the back of the bike. This steep angle moves you forward a bit and does put you on the bars when climbing a bit. This seems to counterbalance the short stem you really should be running on this sort of bike and stop the front end lifting on steeper climbs. It feels slightly odd at first, but is well worth it, just don’t try any seated descending!
Our man in the field Tom, “Tam” Hamilton is the designer behind the Pinner, as well as being the guy who writes “The Science” articles for our bike tests. We caught up with him to get our heads round the intricacies of the suspension, as well as the challenges and tweaks required to go from 26 to 275. Over to you Tam…
I’ll start off by saying that I have no idea who designed the Pinner; they must have been a right muppet! They got it all wrong and then put it together with weird skinny tubes… Just kidding, the Pinner is my baby!
It has a single pivot with linkage actuated shock. We use a linkage to actuate the shock because it lets us tinker with the leverage ratio separately from the main swingarm. This allows us to optimise both the geometry of the bike and the leverage ratio, rather than having to compromise on one or the other. The leverage ratio is linear progressive; 3.15 – 2.45. Well, its as linear as I could get it…you wouldn’t be able to feel the slight wobble at the beginning and end of the travel, especially with an air shock. Obviously this is what I think is the best amount of progression for how we wanted the Pinner to ride.
The axle path is the only aspect where the Pinner 650’s suspension differs significantly from the Pinner 26, and even so it would be very difficult to tell when you ride them. The Pinner 650’s axle path is rearwards to -3.5mm at 55mm travel, then forwards to 5mm at full travel. The Pinner 26’s axle path is rearwards to -5mm at 65mm travel, then forwards to 1.5mm at full travel. Why? Well, ‘BB drop’ (BB height relative to the wheel axles) is pretty insignificant compared with BB height, so both frames are designed to have the same BB height. In order to keep pedal kickback under control the main pivot has to stay a certain distance from the BB. This means that its best to have a lower main pivot (relative to axle height) on the 650B bike, which results in the more forwards axle path. The Pinner 650 does have a slightly longer chainstay to compensate though.
Before we get into pedal kickback, its worth noting that bikes with different sized wheels need different sized gears; a 36t chainring with a 26″ wheel is roughly equivalent to a 34t ring with a 650B wheel, assuming the cassettes are the same. This affects the pedal kickback. The Pinner 650’s pedal kickback ranges from 13deg at 10t to 27deg at 42t. The Pinner 26’s pedal kickback is 12.5deg at 10t to 25deg at 42t. As a side note, who an earth can spin a 36:42t gear ratio and actually go faster than a walking pace on a gradient deserving of such a gear?? I cant. 1:1 is the useful limit for me.
So those funky big wheels are great for squashing stuff and getting grip, but with suspension their advantage is eroded slightly by some combination of axle path and pedal kickback.
So to the point of this sort of thing; riding it! The first ride on it was more of a muck about session, riding the jumps, drops and flowy corners of the Black Canon Collective, not far from BTR’s base. From the word go the bike was poised, the supple rear suspension working beautifully with the (potentially unbeatable?!) Marzocchi 350 to deliver a brilliantly plush ride. Through stuttery sections of roots the back end tracks perfectly, the stiffness of the frame combined with the springy steel feel makes you feel invincible. The slack front end (only a degree or so off most DH bikes) is confidence inspiring when the going gets a bit steeper and rougher, and the reasonably short back end means you can chuck the bike through the corners a treat.
We were on the large, and at 5’11 this felt good, but the fully grown might find the bike a little bit short. The beauty of BTR is that they could just make you an XL though! After our first muck about session I had a big grin, but some reservations. This was supposed to be an all mountain, ride all day, trail crusher, yet it was just so supple and confidence inspiring on the descents, it was made out steel, and looked, frankly, a bit small. Not very much sweet talking later we had the bike back in the van and off to North Wales for some longer rides.
After a few longer rides on a range of types of trail from trail centre to freshly raked forest, with a mix of wet, grassy climbs, any concerns we might have had about this bike as an all rounder were long gone. The steep seat tube angle makes the bike a great seated climber, the suspension delivering superb grip without too much bob. Get out of the saddle and the bike does bob a little bit but on really punchy climbs the suspension really helps the grip. Traversey sections are best attacked as with the seat up, it can get a bit scary, and long fireroad drags put a bit of weight through your arms, but this is worth it for the brilliantness of the bike when it comes to descents. On really long rides, the weight of the bike (compared to other bikes of style) it did start to show a bit on the climbs.
At £2500 for a frame and Cane Creek DBair, the Pinner is up at the high end of the trail bike market along side some very sleek carbon fibre offerings from some big names. It has the suspension and the angles to compete with these big guns, and for about the same money you get a bike that is truly yours, right down to the individual head tube badges, add to that the fact that it’s made of steel so will last forever and you have a bike to be proud of. While it can’t quite make it to the best bike I have ridden this year, it is almost certainly the most fun! Well worth a look if you are in the market for a unique frame.
Burf & Tam Racing – BTR Fabrications
Additional Photos – Rab Ward-Davies
