Thorn Mercury 650b owner review

[PH]

First, here is how it was loaded. Ultimately, this configuration fell under the classification "Tried to be clever".

That made me laugh!  But without such cleverness we'd never learn anything.
It's all a compromise and there is only one way to find out what works best for you.  You could just do what someone else has found works for them, and that might be just fine, but you'll never know if something could be better unless you try it.  I'll make different compromises for different trips and am lucky enough to have different bikes to throw into the mix.  I don't always get it right, but can't remember ever getting it drastically wrong, certainly never enough to spoil a trip.  The only camping my Mercury does is 1-3 day trips and one of the days is likely to be without luggage, I try and keep the load below 10kg, though as I'm 7kg heavier than you I have less capacity to play with.  Any trip longer than a long weekend is likely to be 2-3 weeks, I want more comfort and less compromise, my kit is likely to be 16 -18kg, still mostly on the rear and I'm unlikely to use the Mercury. 

[Moronic]

Yes I'll be interested to see how my touring develops on this bike. It's certainly way more capable of carrying a load than the carbon-tube Trek it replaced, and although that has some nice design features it's a toy by comparison. Since I've seen your reports of touring pub to pub with 160km days, PH, I can guess you're producing a lot more power than I am and hence can handle a bigger load and can also stress the frame a lot more.

While I didn't shrug off the 12kg I was carrying, the Mercury certainly seemed to and I'd be hoping to keep loads near there even if I did add capacity for more volume. The interesting question will be whether I can find routes that allow frequent resupply while steering clear of large towns and the vehicle density that goes with them.

How about touring on gravel with a Mercury?

I've remembered I had wanted to comment on this, having given some thought to it during the tour. The key here was to get the tyre pressures down. Once I'd done that I was really impressed with how the Mercury handled the gravel. There was never a moment when it felt unsuited to it, albeit my experience on that front was still quite small. Let's just say I am looking forward to planning a trip on roads that are mainly gravel, and more so than I had been before this trip.

[PH]

Since I've seen your reports of touring pub to pub with 160km days, PH, I can guess you're producing a lot more power than I am...

That flatters me in a way that the reality doesn't! I'm just very comfortable sat on a bike all day.

[Moronic]

Brief report on an experience yesterday arising from my cycle enthusiast brother rocking up for a 90-minute spin where he could try out the Mercury. Mike spends most of his riding time on fast group rides with his full-carbon Trek road bike. But for this ride, which would take place on tar and gravel cycle paths local to me, he had brought his long-time touring steed, a Shogun brand rigid MTB that I am guessing is well over 20 years old.

Mike liked the Merc, but the most interesting discovery from this exercise may have been mine. The Shogun was a good bike in its day, built from a butted cro-mo frame in Japanese steel and with a steel unicrown fork. Mike had fitted 26x1.5-in tyres with a road-touring style grooved tread. We rode our own bikes briefly while Mike checked all was well with his Shogun, then swapped. Our inseam lengths are all but identical, and both bikes were equipped with Shimano clipless MTB pedals.

While its derailleurs were old and their cables in need of lubrication, I thought immediately that the Shogun rode really well. It also felt fast, and the drivetrain efficient. We rode a section of the trail I know very well. It includes a steep, bumpy descent followed by a km or so of mainly flat and even more bumpy going, all on tar. The bumps are mainly from where longitudinal cracks in the tar have been patched. I've always felt the Mercury to ride superbly through here, treating he tar almost as though it were smooth and feeling very secure. I was impressed to discover that the Shogun felt great through here too. Steel is real, I was thinking to myself. And, I thought, while the heat-treated steel in the Mercury frame might be better, the Shogun still soaked up the bumps very nicely. We continued on paths that included some gravel and dirt to our turnaround point, where we stopped for a chat and swapped back to our own steeds.



The contrast was immediate and very palpable. The liveliness in the Merc was apparent even at low speeds, and its effect was exhilarating. I had certainly been ready to climb off the Shogun by then, but had attributed my failing enthusiasm largely to the onerous gearchanging and painful plastic saddle. Suddenly I was newly aware of how comfortable and encouraging the Merc was by comparison. It felt like it was half the weight of the Shogun (real difference may have been under a kilo, with the Shogun having been stripped of ancillaries), rolled much more easily, and had a drivetrain significantly more efficient. It danced where the Shogun had plodded. Mike spoke of the Mercury having elicited in him a sense of ease. Having reflected on my experience over the ride home, I proposed that when I had regained my bike I felt like I had stepped off a very nice little donkey and onto a gazelle.

Of course that hadn't prevented Mike from climbing swiftly past me at a couple of points on the way home. That exciting feel didn't give me more speed directly. However, it had certainly contributed to my putting miles on the Merc over the preceding six months, so that his overtakes had required him to work.

The point is not, of course, that my 3000-pound Rohloff Thorn felt better to ride than a 500-pound MTB built last century and for heavier duty. The point is just the stark difference in feel, unladen, between this workmanlike Japanese frame made from butted cro-mo and Andy B's Mercury design in butted heat-treated cro-mo.

It's a point that may interest people considering a Thorn who are wondering how to evaluate Andy's claims for the Mercury's ride. Could it really feel very different from the mid-price butted cro-mo steel MTB, tourer or road bike that I've had in my garage for years, such a shopper may ask himself. Umm, yes it could. 

[JohnR]

Interesting observations. I wonder how much of the apparent difference was due to the more comfortable saddle and sweetly-shifting Rohloff hub which may be slightly less efficient than a derailleur system in optimum condition but the balance changes when the derailleur system gets used.

Does your chain need adjusting? It looks a little slack in the photo.

[PH]

It's always a pleasure to read you enthusing about your bike, we share some of the same opinions, though I'm a little maybe less sure about the attributes that lead to them.
Unless all other factors are the same it isn't possible to single out an element with any degree of certainty, in this case the glaring difference is the wheels and tyres.  I swapped my Raven (Which I liked in an unexcited way) to a custom ti frame, same hubs and attachments, slightly heavier, same riding position, different steering geometry, completely different feel.  Was that the frame material, geometry, wheel size, tyres? I have no idea, maybe a combination of them all. I'm not saying one was better, but I far preferred riding the ti bike, just felt more rewarding.
That's the point - if a bike feels fast it is, partly because that feeling is more important than the numbers, and partly because if it feels more rewarding to put the effort in you will. But they have to be radically different bikes to alter the physics, something like 90% of your effort goes into displacing air! We only have that 10% to play with, that's why your brother will pass you on either bike, that's why my Audax time on the Raven wasn't hugely different to on the Mercury...

I don't know why I like riding the Mercury so much, that mix of compliance and stiffness which I think comes from the tube shaping contributes, but I suspect it's mostly about the geometry.  Apart from passing some time on a forum, I don't need to know...

[Moronic]

Its a strength for readers and a fun element of posting a review like this here that others experienced with Thorn can add critical analyses.

There is a story posted here from a 1996 magazine in which an Italian maker built seven bicycles to order that were alleged to be identical except for the steel in the frames, which ranged across the Columbus range from straight gauge manganese moly to butted heat-treated cro-mo. The writer couldn't distinguish the two extremes in a blind test.

In another fun story posted here along similar lines, the testers could distinguish a frame built from expensive heat treated steel pretty easily from one that was not, and in a blind test preferred the one that was not.

Simple logic dictates that the tube material doesn't tell the whole story. If it did, then a frame of 5mm wall thickness tubing that weighed 20kg bare would feel the same as a frame in typical bicycle gauges.

Nevertheless I'm pretty comfident in attributing the liveliness I reappreciated in the Merc to the frame. Obviously it's not just the frame material that generates the feel but also the design. And for all we know, the special skills of contemporary high-end Taiwanese welders.

Yes, other bits also contributed: comfort, geometry, Rohloff slickness, tyre size, the presence and absence of inner tubes, etc. If we can accept that these contributed, I think we've poor grounds for ruling out the frame as a contributor.

PH fun story about the switch to TI.    JohnR, the chain seems to be wearing unevenly. I'm happy for now with the tension at its tightest point.

[JohnR]

One factor in steel frame design must be the design loading. I would expect a frame in higher strength steel to give a firmer ride under light loading than a frame in slower strength steel of the same weight. Conversely, the frame of lower strength steel may become too elastic when heavily loaded.

JohnR, the chain seems to be wearing unevenly. I'm happy for now with the tension at its tightest point.

Your chain wear should not yet be perceptible. If the chain tension is uneven when the cranks are rotated then the primary suspect on my list would be that the chainring is slightly off-centre. This can usually be fixed by loosening the chainring bolts, adjusting the chainring position and retightening. It's not unknown, however, for chainrings to be slightly eccentric in which case I would be identifying and marking the tight position and then slightly enlarging the bolt holes to allow more adjustment of the chainring position.

Edit: Inserted missing "not" before "yet".

[PH]

One factor in steel frame design must be the design loading. I would expect a frame in higher strength steel to give a firmer ride under light loading than a frame in slower strength steel of the same weight. Conversely, the frame of lower strength steel may become too elastic when heavily loaded.

I'm sure we've been down this road many times and the answer is always no. As it says in the Bruce Gordon article Moronic linked to above:
"This extra hardness doesn’t help the rider any – it just gives your frame builder something to talk about. But the increased tensile strength allows Tange to reduce the wall thickness, and hence the weight, of the Prestige tubeset without compromising durability or crashworthiness."
EDIT to note that weight saving is a whopping 150g
Alternatively, it also allows a larger diameter tube in a thinner gauge, so a stiffer tube without the weight penalty.

[PH]

Its a strength for readers and a fun element of posting a review like this here that others experienced with Thorn can add critical analyses.

Yes all good fun, though once we stray away from the hard facts it becomes more opinion than analyses 
I'd read those two articles before but not for a while, the conclusions are interesting for what they are, but there's still a danger of extrapolating beyond what's demonstrated, testing A-C and concluding A-Z. Bruce Gordon changed a tube away from the usual, we don't know how much diference that would have made, or if the same experiment in a different style of frame would provide the same results.  The options are pretty much infinite, that's why no two frame builders agree!  Local well established frame builders (Since the 1940's) recommend Reynolds 631 for just about everything, another well respected builder believes Reynolds lowly 520/525 is the best material for touring frames, another has 531 made to special order because they'll tell you there's nothing else like it....
Then there's Thorn's legendry Reynolds sticker from am early Audax bike, I'm not even going to try and guess what was gong on there, but I know a few people who had them and they were apparently the Audax bike to have at the time

[Moronic]

 . "It's that 708 seat tube that makes all the difference."

[Moronic]

I've had confirmation from a recent micro-tour that my Mercury carries a load with much more aplomb when it is biased to the rear.

For the trip I fitted a Tubus Logo Evo rack, which carries rear panniers an inch or two lower and further rearward than the Tubus Vega I had fitted previously. Essentially the Logo is a Vega with an extra rail welded on each side. The rails add about 200g.

I used Ortlieb Back Rollers, and strapped a mattress and groundsheet to the top of the rack. That allowed me more volume than I had available on my prior tour of South Gippsland, without recourse to front panniers, and I carried the same 12kg weight.



Yes I was a little stronger for this trip, and the pace was very easy. Nevertheless I was astonished by how much more easily the bike rode when loaded this way. Out of sight, out of mind? I suspect the more relevant difference was much lighter steering from the mid-trail geometry than when the bike was front loaded, which meant it was  easier and less stressful to balance when climbing in low gears.

I think it would still be great with front panniers added if I needed more volume. But I would aim to place the least dense items up front, and maximise weight at the rear.

I've also abandoned an idea I had about balancing loads front-rear by running small panniers (eg Ortlieb Sport Rollers) at each end, where I need more volume than Back Rollers can carry alone but not much more. I think now I'd stick with the Back Rollers and load them up, and run the Sport Rollers or similar on the front just half full.

It is an advantage of the Logo rack that you get plenty of heel clearance for large panniers.

[SteveM]

Absolutely loved reading of your experiences on the Merc, Moronic thank you.  Surprisingly little on the twitterweb about this bike.

I have acquired a Mark 3 700c 55L (thanks Ray - I named this bike after you!), upright bars and Rohloff - 2021 model.  After years of riding a Boardman Alu hybrid with front suss, this bike came as a bit of a surprise.  The steady plodding performance of the Boardy replaced by a slightly nervous, skittishness that was at first a bit of a shock to the system.  Like swapping a Hunter for a Racehorse.  But over the weeks I have started to get the hang of the lively handling, its definitely a very, very responsive and spritely ride.  I have now swapped out the tires and lowered the pressures slightly and that has tamed the front end a wee bit, but it is still a very sporty ride when unloaded. 

The Rohloff was a shock too.  I found that I was getting some clunky changes at first until I began to 'feel' my way across the planetry gears - just backing off slightly at point of shift and waiting a second (literally) for the gear to engage fully before getting back on the power.  That sounds like the old Sturmey style, but it isnt, takes a second, and after a while you really don't notice - it becomes instinctive.  Once you have developed the Rohloff riding style, its super slick.  Like everyone else says, the whirring noise in 7th is noticeable, but for the other 13 gears the hub runs almost silently (well on my model with low mileage at least).  Now, I'm loving the advantages - changing down at junctions, slipping down 10 gears at the top of a climb ready for a descent (no more mad spinning as the derailleur descends and the front cogs drop.  Just makes things so much easier.  Its a wonderful thing.  And maintenance is a complete joy.  Compared to the SRAM single its a marvel - gone are the days of endless derraileur adjustments and faffing with shifter barrels - its a dream. 

The frame is super comfy too.  I had a suss front fork and Thudbuster seat post on my hybrid, but honestly, this gorgeous steel frame has so much give (compliance?), there is hardly any difference over gravel - and that's with the ST touring front fork too.  And that means less power lost to the rubber springs and air suss.  It seems to handle gravel really well.  I'm not contemplating devilish rocky trails on this bike, but its just fine and totally assured when I veer off the broken British tarmac and onto the quiet byways.

I swapped over my B17 Special onto this bike - I have had it and cherished it for over 10 years and that makes a huge difference on a new bike - new suit, same shoes.  All I can say is, my Strava segment times are coming down across the board - hills, flats, downhills and offroad.  Some of those best times were set on a Surly Pacer audax bike, so it shows how good this bike is.  I'm 10 years older and heading towards 60 and the bike still hauls me along at a good brisk rate.   

The frame finish is exceptional.  The brazes do show, they are not super smoothed like in the old days but they are immmaculate. The lugs are wonderfully crafted - a work of art. The paint is gorgeous in glossy gunmetal grey.  Its one hell of a bike. 

So, my next question for you Thorn gurus is about the loading.  It certainly has all the lugs and eyelets that you need for 'light touring' (Andy's phrase), the 'Bible' says the 'sweet spot' for loading is 25kg distributed 30/70 (ish) front and rear.    I have not yet fully loaded up the Merc, that will come in Spring with the Canti Way and then France (Eurovelo 4 in Brittany).  25kg (50lb) seems plenty to me - I still recall lugging a 35lb backback on my DoE Silver trek - that had three days kit and heavy old fashioned stuff in 1979.  So getting under 25k with lightweight gear should be no problem (OK so I still have my Saunders Jet Packer but that is a thing of wonder and still mint after 30 years - a keeper).  Most bikepacking set ups are way under 25kg, so I can't see an issue (again Thorn underselling?). I use the traditional approach of front and rear panniers (I know, I know, so old school right?). 

Absolutely loving the Merc, for me Thorn are the very best despite all the flat-earth posturing they do (I see they will now split the frame for Gates belts!!! - there must be huge angst in Bridgewater over that).  I completely trust Andy and Robin - the mechanical TRP Spyke rear disc and front vee brake option that baffled me at first now makes total sense.  As does the geometry, long stem and flat bar options.  They just get it bang-on.  The bike fits like a glove and even for this old dog, its just so comfortable over the long haul - no more aching neck and back.

I'm never going to circumnavigate the globe - I don't have enough life left for that.  My trips are a week, two weeks - maybe three at absolute max.  My mileage is in 100s not 1000s per tour and a chilled 50 miles per day. I'm definitely a cycle-tourist! I was wondering if any of you Thorn devotees have toured a Merc and what were your conclusions?  I really would love to know.

And on a final thing.  I ride pretty much solo all the time.  Its not necessarily out of choice.  I do love the solitude, but sometimes, when I am hanging around waiting for darkness, it would be great to share a beer and some laughs - oh yes and to hug a wheel into the wind!. So jealous of the couples I see touring together - Mrs M will just never be persuaded!  What are your thoughts about three weeks of solitude?  Is it even a thing?  Cycling is a love affair, so that is never going to stop me.

Anyway, if you have made it this far, thanks.  Any insights would be greatly appreciated.

And, I love riding this bike. (Did I give you that impression?)

[geocycle]

That’s a nice write up Steve! I have a Raven Sport Tour which has many similarities with the Merc, bar the wheel size. I certainly recognise the skittish start which then became silky smooth when you adapt. I don’t camp so will not carry more than two panniers part filled and a bar bag at most.  I also tour solo which I must prefer as you can meet up with people for chats easily enough. Having complete confidence in the bike helps when riding on your own.

[SteveM]

I think you are right #geocycle, I have always ridden solo, apart from the odd day ride.  So, that's how it will stay I think - cycle at my own pace and do my own thing.