Behold the Frankenthumper (aka Project 279)

I’ve been riding my Hammerhead Thumper for more than a year now and have been getting on with it pretty well, it’s not perfect but it’s a pretty capable and versatile 130mm 29er that I’ve ridden on the sort of trails I used to need a 160mm 26in bike for. And it’s usually been quicker.

After reading about 650b-plus tyres I’d decided they could be worth investigating, maybe lowering the BB a bit and injecting a bit of fun into the steamroller-like ability of the bike. So when Superstar were doing one of their promotions I snapped up a set of 650b wheels with 25mm internal width rims with the intention of mounting 2.8in tyres on them.

Then I changed my mind.

frankenthumper
Well I think it looks better with the smaller rear wheel. Definitely more aggressive anyway.

It turns out the rims are probably a bit narrow for such wide tyres, going by other riders’ reports – and I’d probably need rims in the region of 30mm to 35mm internal width instead.

However in the course of investigating the B-plus thing I’d swapped a few emails with Stuart at Blue Flow Bikes (the importer of the Thumper) and he’d shared a vague plan he had to try a 650b rear wheel in his bike.

This must have planted a seed in my mind, because the next thing I knew I was buying a 650b Schwalbe Hans Dampf tyre – in the excellent SuperGravity carcass of course – and scraping together bits of tubeless tape to set it up on my new rear wheel.

It took about 15 mins to swap the cassette over, attach a spare brake rotor and align the caliper and then I was off for a quick spin on my local trails – mainly singletrack with a couple of steep sections and a few drops and jumps.

First signs were positive. Very positive in fact.

The bike had been given an average height BB when it was designed, but changing fashions had left it a bit on the high side – which created a feeling of being perched in some situations.

With the BB now significantly lower, it felt like the bike was carving every turn and glued to the ground. “Planted” is the word I’d use. Steep trails were also easier now.

The next day I managed to head out to Rivington for a proper three-hour test run, with 1,000m of climbing and descending on almost all of my favourite trails (which were running very fast).

I usually like to keep my reviews quite loose, but I’m going to split this into categories to make it more easily digestible.

Climbing

There’s always a climb at the start of my Rivi rides and it felt like business as usual as I began pedaling up the wide cobbled track from the top barn. Maybe the going was just a little bit tougher than with two big wheels, but if so it was a very subtle difference.

As I came to some mildly technical sections on the climb I was surprised to discover that it felt noticeably easier, maybe due to the lower centre of gravity. Whatever it was, I noticed the same thing repeatedly on the ride.

On the flat

And after the climb there’s usually a flat traverse, some of which is smooth and some with pronounced cobbles – the latter being where I’ve found 29ers have really shone in the past.

This is where I found the 279er’s biggest flaw – it doesn’t carry its momentum nearly as well as a full 29er over flat bumpy terrain. The rollover effect is still there in the front obviously, but I could feel the rear creating a bit of drag.

On smooth ground it’s less noticeable but I’d still say it’s a touch slower.

One plus point is that it’s now a little bit easier to hop between lines when riding complicated trails on the flat. Less gyroscopic force to overcome I guess? (I am not a scientist).

frankenthumper
From another angle, just so you can see the wheel difference more clearly.

Downhill

First off came a mixed run through the terraced gardens, which were happily deserted on this overcast weekday afternoon. Getting the hang of how it handled by the mid-way point, I found the low BB again proving useful as the trail steepened and headed into a series of rooty turns with a three or four foot drop off. The following super-fast terraced singletrack was slightly less nervy than usual, possibly due to the increased stability.

Then I had a few runs down one of my favourite bits of woodland singletrack. A couple of off-camber turns followed by some roots, steps, some flat turns while dodging trees and a sort of bombhole followed by a steep little drop to finish. All good again and Strava later revealed I was only one second off my PB – set on my Patriot in slightly better conditions.

The pattern was repeated across the hillside – though I did identify another (not unexpected) drawback on the long, gently sloping Shooting Huts descent. Pedal strike!

A poor bit of timing saw my left pedal clang loudly on a trailside rock, but I stayed on the bike thankfully and made a mental note to time my pedal strokes better.

Interestingly, the reduced rollover effect was not as noticeable heading downhill. There was definitely more feedback through the pedals when hitting rocks or landing drops – but I didn’t notice any feeling of the bike “hanging up” apart from on trails that were close to flat.

Another big plus for me is that the bike is now much more manageable on steep turns such as switchbacks. There’s a right-angle turn at the bottom of a steep flight of steps (the end of the Shooting Huts descent for Rivi riders) which I managed to make it round for the first time on the 279er.

Attitude adjustment

For me the change has been a revelation on a bike that I thought I knew really well. I’ve written a lot about the bike’s abilities above, but what I haven’t said is that it was a whole load more fun.

There’s now a real “in the bike” feel to it – almost a “behind the bike” feel – and it’s more confidence-inspiring, making me more likely to just drop into a steep trail or hit a jump on sight.

I almost found myself making motorbike noises at one point. And I don’t even like motorbikes.

Of course the bike’s not perfect. It could still do with a bit more length in the front end and I’d like to add 20mm travel while shortening the chainstays by a similar amount.

Those mods might be a bit harder than just sticking a different wheel in though.

 

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