Bikes are getting slacker. Each season, head angles seem to tend a little more towards the horizontal. Not so long ago, the standard head angle for cross country bikes was a 71 degrees, downhill bikes sat at around 65 and trail bikes were at 69.5 degrees. Now those figures are more commonly 69, 63 and 67.5 respectively.
But why? Simply put, riders are going faster. Better suspension, stiffer frames, grippier tyres and more powerful brakes mean that riders are tackling descents more quickly than ever before, and not just on downhill bikes. The quicker we start going downhill, the slacker bikes become.[private]
But what if your bike isn’t quite as you’d like it? Increasingly, we’re seeing riders looking for ways to tweak their bikes and bring the geometry into line with the longer, lower, slacker trends. This customisation mainly happens in the downhill world, but more trail riders are looking for the same benefits too.
A simple, light and easy (and cheap!) option is the Burgtec Offset Shock Hardware. We stumbled upon these when looking for a way to slacken the geometry of our Yeti 575 trail bike. The head angle on the Yeti 575 (2010, 25th anniversary model) is 68 degrees, and we were looking to drop it back to 67-67.5 degrees.
The Burgtec hardware looked to be just the ticket. There are kits available to suit most bikes, and a quick trawl showed that their were kits to suit the 575.*
The simplicity of this item is its strength. The Burgtec hardware replaces the existing mounting hardware in your rear shock and installation is a five-ten minute job, depending on how tricky it is to remove/install your shock. Simply pull out the old hardware, and press in the new. It’s all machined from titanium and has precise, snug fit. The weight difference is negligible, and the titanium should outlast the standard soft aluminium hardware.
So how does it change your bike’s geometry? Rather than having the bolt hole drilled directly through the centre of the shock hardware, the Burgtec hardware offsets the bolt by 3mm (or 4mm if your bike uses a 6mm mounting hardware, rather than the more common 8mm). This effectively shortens the overall length of your shock, consequently lowering the bottom bracket and slackening the geometry. Simple!
We only installed the kit into one end of our shock (unfortunately, the 2010 Yeti 575 uses super narrow shock mounting hardware on the rear eyelet, not currently available from Burgtec). This had the effect of slacking the bike by half a degree and lowering the bottom bracket by just under 5mm too – exactly the result we were looking for!
With the bike lowered and slackened a touch, the 575 is an even more stable descender, and more confident through fast corners. It’s not a night and day difference, but if you’re in tune with your bike you’ll appreciate the changed ride characteristics.
All up, the Burgtec Offset Shock Hardware is a simple, effective solution for those who want to tweak their ride. If you’re keen to see how slacker geometry could change your time on the trail, this is a great option.
*Before you go rushing out to install the Burgtec hardware and smashing every downhill, something to be aware of! Because the hardware ‘shortens’ the length of your shock, you need to make sure your tyre or parts of your frame aren’t going to bottom out and smash into each other under full compression with the hardware installed. Install the hardware, let all the air out of your shock (or remove the spring) and full compress the suspension to check for contact points before riding. [/private]