Thorn Mercury 650b owner review

[Andre Jute]

I feel your loss, Moronic, not least because I was looking forward to riding vicariously with you on your fine-looking new bike once your ride report(s) arrived.

I was amazed to read up-thread in your discussion with Mike about fine bicycle paths in Melbourne. When I lived there in the early 70s, you could ride along tram tracks that would mangle rims and put you down, or beside the beach in the middle of the night to escape the trucks from the Port in the daytime. Often on fine summer evenings after work we used to ride around and around the gardens in front of my house in St Vincent Place, or around and around the lake in Albert Park next door. Rush hour traffic, what rush hour traffic? Nobody even dreamed about bicycle paths...they were a political impossibility.

[JohnR]

Is the distance limit based on length of journey or distance from home? I recall that during UK lockdown 2 our PM set an example by being seen on a bike 7 miles from home. That suited me as I had a 23 mile circuit which was never more than 7 miles from home. Nonetheless a lockdown scuppers the potential for any proper trips.

[Moronic]

Thanks all for the well wishes. That the trip must be cancelled is disappointing - especially in the timing - but a long way from tragic. Yes I am lucky to have superb cycling paths on my doorstep that give me plenty of scope for touring the interior of a 5km radius over the permitted daily two outdoor exercise hours - and I will be out there.

Andre, I grew up in Melbourne through the 60s, 70s and 80s and you are quite right: there was little public interest in making life more pleasant for cyclists, albeit significant grassroots lobbying that became effective at the municipal political level and probably led us to where we are now. Yes, the tram tracks - I won't forget crossing one at a safe angle on a warm day, only to have a stray sliver of metal spike my front tubular, which deflated instantly. I picked myself off the roadway with cuts and bruises and a flattened rim - and then had to catch one of the trams to a place where I could rendezvous with a driver who got me home. They're still there, but now I could get to many places about town without crossing any.

Albert Park would have been a nice place to live. These days I think you'd roll the kilometer or so down to the bay, and could follow a beachside bike path at least down to Sandringham, with the option of using a marked bike lane on what is called Beach Road. On weekend mornings there may be so many cyclists on that road that cars become second-class vehicles. There may even be special road rules favouring cyclists in place over early weekend hours - I don't get down that way on the bike so this is just from hearsay and vague recollections of road signs I may have seen from a car.

You may be interested in what the City of Melbourne now says about cycling: https://www.melbourne.vic.gov.au/parking-and-transport/cycling/Pages/cycling-lanes-and-routes.aspx

"The City of Melbourne is committed to becoming a cycling city, with a safe and connected bicycling network for cyclists of all ages and abilities."

I grew up on the other side of town and a fair way out, and mixed it with the motor traffic on semi-rural roads through my teens. I was living in Eltham, about 25km from town on the Yarra, and had relatives a little north of Hurstbridge, a further 15km out by road, and so I got to know the roads in between pretty well. I moved across the continent in my mid-30s to Perth, where I was astonished and delighted to find excellent bike paths extending north and south from the city on both sides of the Swan river - a favourite was the 55km circuit from Perth to harbourside Fremantle and back, out on one side and return on the other.

Returning to Melbourne 20 years later I discover that I can ride from inner Melbourne through Eltham and to within 3km of Hurstbridge without sharing even 50 yards of my route with a car - and with work under way on the final kilometres. Much of this trail is paved, but about 10km would be good gravel. It follows local waterways and the railway line. If I swung right before Eltham, I could follow another trail a long way east out Mike's way.

Other directions have good options too. And as many of the trails pass near railway stations, if you get a bit weary you can ride home on a train, with bikes explicitly allowed on board.

[Moronic]

Since this is a bike review thread, I'll add that the existence of this developing bike path network in Melbourne was the key reason why I bought a new bike, and also a key reason why I bought this bike - a Mercury 650b.

I've lived in two suburbs since returning to Melbourne, and easy proximity to a good part of the network was a part of the reason I chose my address. I'd formed the ambition to exercise more, and while I've had casual relationships with swimming pools and gyms I've not developed commitments. In Perth I lived near the mouth of the Swan River and could easily deploy a light sea kayak, but I saw little prospect of doing that frequently in Melbourne. Over the years and with a big gap in my second snd third decades, cycling had been my fitness mainstay. So the thought that I might quickly and safely access dedicated paths was appealing.

If you're planning to go out for several hours at a time, bike trails turn out to be pretty demanding. Their sealed surfaces are less well founded than those meant to carry motor traffic, and less well maintained. Some routes include long stretches of gravel. And they're full of tight turns, short but sharp climbs, narrow bridges, and narrow passages through gate-like structures that have been build to slow users either side of road crossings.

The Mercury with its Rohloff geartrain and big, comfy tyres is an utter delight on these routes, supplying comfort, roadholding and geartrain responsiveness that makes the derailleur machine it replaced feel like a relic of the steam age in an era of electric locomotion. "Here already?" Is a frequent thought at waypoints I pass on the Mercury, and that is not only because my capacity is growing swiftly. There is just so much less stress involved. I won't repeat the many explanations for that comment that I have given already.

The extra bit of course is the anecdotal evidence that public investment drives private consumption.

[Andre Jute]

For a car culture, those are amazing, light-speed developments. Thanks for the link, containing even more amazing intentions.

[GamblerGORD649]

@JohnR   Nice rig, but why is the frame lock on the wrong side of the stay?? Where it is, a thief could just undo those 2 nuts and pull the whole wheel off. NOT possible if lock is still attached to the wheel inside the triangle.
My new Simcoe roadster came with the brazeons and 5 mm bolts for one of those, inside the triangle.
The only reason I stayed closer to home in lockdowns, is the cafes and service stations all closed the washrooms and benches.
The OPs rig doesn't get much better either.

And speaking of WEIGHT, LOL, a week ago I rode my 76 lb Rohloff tour bike, 128.6 miles on the hilliest highway here. Home is 664 m, and there's high points of 802 and 794m. Near 10 hours moving and 14Hr20min clock. My Olympic road ride. LOL. They went 16 miles farther and took 6:03:xx, but my bike is 60 lbs heavier and I'm 42 years older, and NO peloton. LOL. I lost near 7 lbs of fluid weight. So I was bonking and cramping. Over 25 miles I had to dodge the damn shoulder cracks. My mirror is indispensable for this. My Rohloff is working better every ride.

[Danneaux]

[I split the thread as it had wandered from Moronic's engaging account detailing is own Mercury to a discussion of weight. The weight discussion is here:
http://thorncyclesforum.co.uk/index.php?topic=14318.0 -- Dan.]

[JohnR]

@JohnR   Nice rig, but why is the frame lock on the wrong side of the stay??

Because Thorn put the rear brake cable on the front side of the chainstay (see photo).

And speaking of WEIGHT, LOL, a week ago I rode my 76 lb Rohloff tour bike, 128.6 miles on the hilliest highway here. Home is 664 m, and there's high points of 802 and 794m. Near 10 hours moving and 14Hr20min clock.

That's a long ride! Double the distance of my longest LEJOG day but less than double the time.

[PH]

why is the frame lock on the wrong side of the stay??

There isn't a "wrong" side, it does the same job either way, AXA used to sell a bracket (Might still) to fit it to the outside using the brake lugs.  I was looking at a Tern cargo bike that has one fitted to the front wheel, now that did look wrong, but again it was doing the same job.

[Moronic]

[I split the thread as it had wandered from Moronic's engaging account detailing is own Mercury to a discussion of weight. The weight discussion is here:
http://thorncyclesforum.co.uk/index.php?topic=14318.0 -- Dan.]

Good idea to split the thread but the weight discussion remains relevant for many considering any Thorn, I imagine.

People coming to this review from curiosity about Thorns might learn something from the weight thread as well.

[Moronic]

With a few more miles on the Mercury I can add a bit to the review. First thing to say is that the bike continues to delight. I'm using yet more presssure in the Schwalbe G-One Speeds x 50mm and now running about 40psi F and 48R. Notwithstanding what Jan Heine over at Rene Herse says about his tyre range it is pretty clear the bike rolls quicker at these pressures than at the 30-35psi I was running initially, and the main effect on comfort seems to be that the tyres flex less and the frame more.

I would still run the low pressures if I expected to spend a lot of time on really rough stuff, but at present I really like the firmer tyres and not least because they make the frame work. Even with the Reyolds ST v-brake fork fitted, the Mercury feels fantastically lively and resilient. Why this springiness in the frame should make the riding feel so enjoyable I don't know; I just know that it does.

BTW can anyone tell me what sort of steel goes under the label Reynolds ST these days? My guess would be that it's a thick-walled version of 631.

I'm getting stronger quite quickly and more often find myself spinning out in top (remembering that I selected a 37-19 overall ratio for what might fairly be called a great-granny bottom gear, at 15 inches). It's become unusual that I get down to that gear and my thoughts have turned to adding teeth at the front. However I find it quite pleasant and motivating to be grinding up a steep grade in third at 19 gear inches with the knowledge that I have in hand two further reductions, each of 15 per cent. I am quite sure the lower ratios will get more use if lockdown ever lifts again and I can get out for a proper loaded tour.

I am getting the hang of the Rohloff gearchange, and have just about mastered the recommended technique for shifting under load, which is to do so when the crank arms are vertical. Already I have become much more confident that I can swiftly drop a ratio or two in the middle of a steep ascent than I ever was in derailleurs. I've no complaints about the spacing of the ratios, and more and more of my shifts happen almost imperceptibly. I continue to experience the Rohloff drivetrain as highly efficient, in the sense that I am constantly surprised by how much progress I make with so littlle effort.

My choice of 650b x 50 tyres was driven partly by the good proportion of gravel surfaces on the best suburban bike trail I have access to and partly by a desire to avoid motor traffic when touring, which in southern Australia can be met by avoiding sealed surfaces and choosing instead gravel backroads. On gravel sections of the trail it occurs to me to say  something here about Thorn's promotion of the 650b Mercury as a gravel bike. Given its provenance as an Audax-style fast road bike, might that be just hopeful marketing?



From my experience so far I'll respond with an emphatic No, and a caveat. On the big-volume 650b tyres the Merc rides beautifully on gravel. There is extra comfort over narroer rubber, but there is also extra flotation and that feels very significant. On my Trek with its 700c x 35 Schwalbe slicks entry to a gravel section felt immediately slower, as the tyre bit through the gravel surface, and less secure. On the 650b Thorn I don't even notice that the surface is slower, and the security doesn't alter much either. On the Trek I was always glad to regain the tarmac; on the Thorn I'm indifferent as to whether I'm on tarmac or gravel. Which I suppose means it's a gravel bike. The steering seems to work really well on gravel too. And of course, it's nice to know I'm not bathing 3 + 8 (or more) cogs in fine grit.

The caveat is that some reviews of gravel bikes seem to see them as alternatives to mountain bikes, and I don't see that potential in the Mercury. I expect it will be brilliant on just about any road or track where you would comfortably point a 2WD car, but I'm not so optimistic about its performance on the sort of rocky, rutted track that would challenge a wartime Jeep or an off-road motorcycle. I'll likely restrict it to the sorts of tracks I'd consider tackling in a sporty looking luxury SUV.

[PH]

BTW can anyone tell me what sort of steel goes under the label Reynolds ST these days? My guess would be that it's a thick-walled version of 631.

I'm enjoying your growing appreciation, whatever we've discussed about what makes something the "Right" bike you've obviously found it here.

In the latest Reynolds parts list I have (2018) there are only two tubeset forks blades listed, 853 and 631.  There are several other blades listed as "Reynolds 'R' Butted Fork Blades" and as Thorn haven't given them a number I suspect it's one of these. Looking at the dimensions and the butting, there doesn't seem to be much difference between these and the 631, so probably just a different alloy.  Apart from those listed as disc, 1.0/0.6 seems to be the thickness used by most, with very little difference in diameter, including the 853 which surprised me a bit, though it doesn't give the profile so maybe the thicker part is longer or the taper to the butted more gradual.  Plus, as we know, Thorn are not restricted to what's in Reynolds parts list....
Thorns previous 700c only ST fork was Reynolds 531, I haven't seen those blades in a parts list for a while, though apparently Reynold will still supply on request. Whatever they were looking for with the newer forks, I can't see it having strayed far from that tried and tested formula.

[JohnR]

Page 11 of the touring bike bible http://www.sjscycles.com/thornpdf/thorn_mega_brochure.pdf discusses frame materials and page 30 discusses the non-disc forks (Reynolds 853 steel). My Mercury has the disc brake forks and page 31 says these are "Heavy Duty  Cr-Mo Steel" without specifying any details. They are stiffer due to the need to accommodate the extra torque created by the disc brake and I place a lot of value on stopping ability in adverse conditions. The Mercury brochure http://www.sjscycles.com/thornpdf/BUILD8MERCURY650bROHLOFF.pdf indicates Reynolds 853 steel for the frame and Reynolds 725 for the stays.

The key to using the Mercury on bigger / looser gravel is probably bigger tyres with more tread. Page 31 of the bible shows that the non-disc form can only take up to 54mm tyres but the disc fork can accommodate up to 65mm without mudguards. I can't see any similar details for the rear tyre options.

[PH]

Page 11 of the touring bike bible http://www.sjscycles.com/thornpdf/thorn_mega_brochure.pdf discusses frame materials and page 30 discusses the non-disc forks (Reynolds 853 steel).

There's three current Mercury steel forks, the disc you have, the 853 I have and the ST that Moronic has.  So between us we have the full set. 
There's also a couple of previous versions, though they were single wheel size, there was a QR disc fork and a 531 ST which I also have.  The ST is a bit heavier and stiffer, but unlike the 853 you can fit a rack.  I haven't looked in the Mega brochure for a while, but I'm sure it's all in there.

[Moronic]

I must be close to capable of reciting the mega brochure by heart, after hours of trying to discern from it whether a Mercury would satisfy or disappoint me.

Thorn on p30 says the fork is Reynolds Super Tourist steel. I was hoping someone might know from arcane sources what alloy the current version of Reynolds Super Tourist was made from.

Weirdly, the table on p31 specifies "heat treated" for the 650b/700c ST fork but omits this for the 700c-only fork. Reynolds 631 is not heat treated.

Thanks for all the info PH and JohnR. I'm still curious, so might send an email to Thorn.

Bottom line though, it's a superb fork for my application. Hard to imagine the 853 version could be better even unladen - but then PH you don't need to imagine.

JohnR it looks like the disc version gains 20mm of clearance axle-crown from using the twin-plate crown. Hard to see from the pics but that's what the table tells us. Hence the bigger tyre compatibility. Yes I'm not clear either on how that works at the rear.

I'm glad if people familiar with the model are enjoying my extended reflections. My idea was to write the sort of thing I'd love to have read myself when I was shopping.

I'm also interested in generating an antidote for the misinformation that still comes up quite prominently when you Google Thorn or Rohloff. Apparently Thorn bikes are appallingly ugly, burdonsomely overweight, and stubbornly old fashioned, while the Rohloff feels like you're pedalling in treacle and its seals apply a drag brake that restricts your speed on downhills.

My reality with the Mercury opposes all that directly: the frame is beautifully shaped and finished and its proportions are very pleasing to my eye; the weight impost for steel is negligible; the design for a bike with this use-envelope leads the market; the Rohloff feels like you're pedalling in Teflon; and the Rohloff applies no restriction on your speed downhill or anywhere else. I hope Thorn gets around to ordeing more frames.