Cycling Gear

Thoughts on the Thorn Sherpa Adventure Bike

Now approaching it’s second birthday, my red Thorn Sherpa has carried me around the North Sea Cycle Route and the Atlantic Seaboard.  Time to reflect on the quality and performance of a dedicated touring bike after a fair amount of abuse.  I would estimate it has covered 10,000km over 100 long riding days, perhaps as much as 50% off-road.

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I purchased the bike with a few sensible modifications and added an Alpkit Frame Bag and Ortlieb panniers:

  • Thorn Sherpa Mk3 frame 600L – straight bars
  • Shimano Deore hubs, 10-speed triple chain-set (48/36/26) / cassette (11-36) with XT 9-speed rear derailleur and Dura Ace thumb shifters
  • Andra 30 wheels, standard front and CSS rear, with XT V-brakes/levers, standard brake blocks front, Swiss-stop blue pads rear
  • Schwalbe Marathon Dureme 26 x 2″
  • Brookes B17 saddle
  • Shimano T780 SPD pedals
  • Thorn expedition racks front and rear and a T-bar extension for the handlebar bag
  • Ortlieb Front Loader Plus and Bike Packer Plus panniers
  • 20-year old Ortlieb front bag
  • Cateye Volt800 front and TL-1000 rear lights
  • Bordo 6000 lock

Over a period of 2 years I have changed:

  • 3 chains – replaced with Shimano HG-X 10-speed
  • 1 Marathon Dureme tyre (rear)
  • 5-6 front brake blocks
  • Shimano T780 pedals for Shimano T8000
  • Front hub outer cones and bearings
  • Complete chain-set for an XT M780 triple (42/32/24), including Bottom Bracket
  • 11-36 cassette

I was expecting greater durability from the transmission, but given the wet, gravel, cinder and off-road tracks I frequented, I am happy with the 6,000km the original set covered.  Finding HG-X chains at bike shops proved difficult, as they tended to cater for road bike transmissions.  I changed these every 3,000km.  After the major service, I replacing the entire system with lower gearing XT chain set. The 42/32/24 front chain rings gearing are my preferred my choice now – they are more durable and ideal ratios for pushing heavy loads up steep hills.

The Dura Ace thumb shifters are great and changing gear becomes second nature after a while.  Gear changes have been faultless and accurate on the whole.

The bottom bracket came loose after 2,000km due to a broken spacer shim, easily fixed.  But the bearings were a wreck shortly afterwards as water had found it’s way into the frame and bottom bracket cavity.

The tyres are superb, offering grip and durability and tackling loose gravel and heavy conditions easily.  However, the replacement pair doesn’t seem to be lasting as long, perhaps they are using a different compound.  Highly recommended blend of off/on-road touring tyre.  I replace the rear when it approached zero tread and carried a few nasty lacerations.

While the rear wheel is still on the original Swiss-stop blue pads with virtually no wear, the front eats through blocks at an alarming rate in bad conditions and has eroded a channel in the rim that will need replacing soon.  The Deore front hub had badly pitted cones when inspected after 6,000km. So a new wheel is needed in the near future.

The Thorn recommend combination of carbide and alloy rims works very well.  The rear has plenty of stopping power in the dry, but needs to be warmed up / dried off to work at all in the wet.  Hence the need to depend on the front standard setup too.  Overall a powerful set of brakes that give reassurance for a heavily loaded bike, if they are in good condition!  I found myself adjusting the brakes while descending in the wet and once demolished a set entirely in 2 hours when riding on the Cinder Trail into Whitby in very poor conditions.

The wheels still run true and contribute to the superb handling characteristics of the bike, especially off-road or on a steep decent, carrying heavy loads (25-30kg).  The frame is supremely comfortable, stable and compliant.  The tyres, together with the steel frame, provide sufficient suspension at 40/45 p.s.i.

The Brookes saddle is now very supportive after running-in over 500 miles and I do not get any saddles sores.  The geometry of the bike meant no particular strains or injury – a credit to Thorn for fitting the bike so well.  The original Shimano T780 pedals slip badly on the non-SPD side in wet conditions, but the T8000 replacements are very good and have not rusted.

The Ortlieb panniers were gutted of all unnecessary pockets and have proven to be watertight.  I have a total of some 80 litres capacity – more than enough for a long term camping and cooking configuration.  They fitted securely to the Thorn racks, which look as if they could carry much more.  The Alpkit custom frame bag carries tent poles, pump and items that I need ready access to, such as sunscreen, chain oil, pegs, first aid and the like.

The Cateye lights were bright and an essential aid to safety in the mist, rain, fog and heavy traffic conditions.

So, in hindsight, what would I change?

  • I would seriously consider the Rohloff hub Nomad or Raven. I hate cleaning derailleurs.  It was trade off between cost, convenience and durability. £1000 goes along way towards paying for a long trip.  I like the thought of linear gear change, maintenance free operation and long term durability, but most of all – no messy cleaning
  • Perhaps a front disc brake – if such a configuration was available.  I am alarmed at the durability of the brake blocks and rim.  The rear Swiss-stop setup has been fantastic, in the dry.  Perhaps I need to find other compounds and avoid the cheaper brand brake blocks
  • Better hubs and bottom bracket – I would choose perhaps XT items or Hope Engineering sealed units.  The Deore units, with the exception of the rear hub, do not seem to last long.  Perhaps this is due to the bad conditions and ingress of water and grit
  • Better transmission components.  The cheaper Deore chain set wears quickly and the XT chain rings are more durable.

But not much else.  I am very happy with the bike overall, specifically with the way the bike handles in a variety of conditions that would leave a road bike floundering: High speed decents (up to 40mph at times); rough ex-railway tracks; canal towpaths; forestry tracks and gravel paths are where this bike works best.  Yet on the road the bike rolls along nicely too, the tyres are excellent and I do not worry about potholes and poor road surfaces that are all too common nowadays.

So this bike is a keeper and will certainly outlast my ambitions.