Interbike: Trek Top Fuel and BMC Trailfox

More ride reports from the Outdoor Demo

Trek Top Fuel gets a dose of nitrous

Trek introduced its revamped Top Fuel to the world two months ago but this year’s Outdoor Demo provided the first opportunity to actually throw a leg over one.  It was well worth the wait.

We extend our apologies to current Top Fuel owners as the new version is no simple evolutionary step forward.   The 2009 Top Fuel’s lighter weight is substantial (and noticeable) but we’re far more excited about the improved overall feel and suspension performance.  

The stiffer chassis accelerates more enthusiastically yet the new carbon frame also provides a far smoother ride quality as opposed to its forebear’s occasionally chattery feel; the word ‘glide’ wafted through our minds more than once during our two-hour ride through Bootleg Canyon.  

While it’s difficult for us to say whether or not Trek’s ABP (Active Brake Pivot) system offers a real-world advantage in this shorter travel application, the new rear end is still clearly better able to keep the wheel firmly planted than before.  It’s still effectively a single-pivot system but careful tweaks to the suspension rates and Trek’s Full Floater dynamic shock mounts seem to be doing their job.

Our Outdoor Demo tester wasn't in full production trim, though: the flat bar was swapped for a wider Bontrager carbon riser and the high-zoot carbon clinchers were traded in for more standard Bontrager Race X Lite wheels with aluminium rims.  Both changes were geared towards better survivability amongst Bootleg Canyon’s endless minefield of jagged rocks.  We expect things to get even racier once we get a hold of a properly outfitted long-term tester but for now, our initial impressions are very favourable.

Hot laps on BMC’s new Trailfox

BMC improves on the promise shown with last year’s Trailfox trail bike platform with an all-new version for 2009.  BMC continues on with its dw-link-esque APS (Advanced Pivot System) suspension design but travel on the top-end TF01 grows to 140mm.  The revamped rear end also thankfully cuts the chain stay length to a far more reasonable 433mm (17.05"); last year’s Trailfox was a rangy 450mm.

Frame weight has dropped, too, and is now down to 2.55kg (5.62lb) without the Fox RP23 rear shock.  There’s extensive use of hydroformed triple-butted 7005 aluminium, the bottom bracket and main pivot are forged in halves and then welded down the middle to yield a hollow shell, the upper link uses similar forged-and-welded construction and the rear brake is now post-mount for use with 185mm rotors.  Pivot hardware has also grown in diameter and now uses Loctite to prevent loosening.

Hopefully BMC will use a little more Loctite than was used on our Outdoor Demo tester, though, as the main pivot backed out about 10mm during our quick trial.  To be fair, Outdoor Demo bikes tend to be the most heavily thrashed of any demo fleet but this raised our eyebrows nonetheless.

Save for some nasty creaking (we didn't notice the loose pivot hardware until nearly finishing the ride), the APS rear end still did a good job of hugging the terrain and it also pedaled pretty well considering our hasty shock setup.  The shorter chain stays also make it easier to lift the front end when needed.  

The BMC Trailfox's overall handling seemed reasonable enough even with the odd setup of our demo ride: the zero-offset post was paired with a long 120mm stem that yielded a decidedly forward weight orientation.  Production units are more likely to come with layback posts but even so, the top tube felt shorter than the 590mm (23.2") figure quoted for our medium size.  

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