Mercury

Issue 41 WINTER 2018

These bikes are designed specifically for use with the Rohloff EX hub

Prices in printed copies of this brochure may no longer be correct. Prices, given in

the online brochure, are correct and will always be honoured.

Thorn Mercury - 8 sizes in 4 colours,

drops or straights, rim brakes or discs.

Short or Long frames, the choice is yours!

You can see the 2 extremes of

Mercury builds above and below.

700c

Size 550S

White Team

Size 580L

Black Retro

SORRY, this is a temporary, not yet fully stripped-out brochure.

There’s much detail which is duplicated in the new THORN MEGA BROCHURE.

CLICK HERE For

THORN MEGA BROCHURE

PARTS 1, 2, 3 and 4

This is a very large file (32Mb) it may take a

considerable time to open, please be patient.

To ORDER:- Phone 01278 441505

or email

sales@thorncycles.co.uk

From:

£2811

Whilst there’s no

such thing as a

Typical Mercury,

most customers

seem to have

spent around

£3200

on their

Dream Machine.

The 4 current colour

options for

MERCURY FRAMES

are:-

GUNMETAL IMRON

COBALT BLUE IMRON

BLOOD RED IMRON

and

GREEN RETRO and

Some of the original colours are still available in some frame sizes:- Matt Black, Black Retro, White Team and Sky Blue Team.

2

Mercury 700c

2

Issue 41 WINTER 2018

Detailed specification of the frame tubes.

The main triangle uses Reynolds 853 tubes in 0.8/0.5/0.8mm gauge. This is the lightest gauge that I’d want to have a frame made from - which, after all, is why I chose it! The down tube is conical 34.9mm at the BB, tapering to 31.8mm at the head tube.

The top tube and seat tube are 30.2mm, this, to my knowledge, is a size never used before. I thought that a 31.8mm top tube was not compliant enough and that a 28.6mm top tube was not stiff enough, on this type of frame. The only possible downside of this size tube is that it will be

impossible for S&S couplings to ever be fitted to these frames.

The 30.2mm seat tube allows the use of a very thin alloy shim to fit the standard 27.2mm seat post, having a shim ought to make seized seat posts a thing of the past. Having a shim also means that the shim can be greased into the frame and a carbon post can be fitted dry, which then means that it doesn’t have to be clamped so tightly. The rear triangle uses heat treated Reynolds 725 tubes. The seat stays are 16mm tubes, which have been heavily ovalised, to give a huge degree of vertical compliance - this makes the frame extremely comfortable over very long distances. The chainstays are deeply ovalised and heavily cranked. The deep oval stays allow for tyres up to 40c, to fit between the stays and the cranked stays give plenty of heel clearance.

The Thorn Mercury frame is a

700c frame, built specifically for

use with the Rohloff EX box hub.

The frame has fairly tight geometry,

similar to a modern Audax bike.

The steel tubes are of the highest possible

quality - I’ve designed and specified every tube

in the frame.

The Mercury is the finest sport frame I’ve ever

ridden - it’s responsive, comfortable and handles

perfectly.

Andy Blance Oct 2014

Above, you can see the deep

drop calliper brake adaptor

and the clearance with 25c

tyres.

Below, you can see the

Mercury also has clearance

for 40c tyres.

The symbol on the front cover and on the top left of this page, is the ancient and still current, internationally recognised astrological and astronomical symbol for the planet Mercury.

I designed the Mercury to be exceptionally versatile.

I designed 8 sizes of Mercury frame. Sorry but there are no extra small or extra large sizes. 4 sizes have long top tubes and should be chosen for use with straight bars. 4 sizes have short top tubes and should be chosen for

use with drop bars, or by cyclists who need a very relaxed position with straight bars. These sizes are small, small/medium, medium/large and large.

I designed the Mercury to accept a wide variety of forks.

We offer a choice of 7 different forks.

The specific fork chosen will determine the specific function of each Mercury bike.

The choice of fork will also dictate which type of brakes

must be used on each build. Please study pages 4 and 5 where I list these forks and describe the implications of

choosing each of them in detail.

The seat stay bridge accepts a special adaptor.

The neat adaptor allows a deep drop calliper brake to be fitted, at close to its maximum drop. Without the adaptor, there is close but sufficient clearance for tyres up to 700 x 40c.

To keep the neat lines and to keep up with customers’ requests, the Mercury is fitted with an ISO disc mount. This mount is cantilevered off the special LHS dropout and it will not interfere with our rear carriers.

I’ve designed a special, lightweight, stainless steel

mini-eccentric BB shell for the Mercury.

This new EBB saves considerable weight and is infinitely adjustable. I have saved weight by keeping the diameter of the EBB and shell to a minimum, however this means that the new eccentric will only throw a half link of chain. It is important that you have one of the correct combinations of ring and sprocket for this amount of adjustment to be sufficient.

Such an eccentric could be a problem on an expedition bike, where a chain may have to be used beyond its service life but I believe that customers choosing a Mercury, will be prepared to replace a worn chain before setting out on a tour, before commencing an epic ride, or before starting on a special long distance event. For more information please see our

document “Living with a Rohloff hub”.

Thorn Mercury 700c Size Matrix

Probable height of cyclist

suitable for this size frame.

Description

of size [1]

Size

[2]

Actual

Seat

tube

C to C

Slope

[1] minus [2]

Seat

Tube

centre of EBB

to top of clamp

Head

Tube

length

Virtual

Top

Tube

C to C

Seat

Angle

With 380mm

Fork

Chain

stay

Mid Tube

Stand

Over

Stand over at front of

top tube

1620 to

1710mm Small

Short top tube 520S 440 80 475 125 555 73.5 431 755 785

Small Long top tube

520L 440 80 475 117 580 73 431 755 785

1660 to

1780mm Small/Med

Short top tube 550S 480 70 515 154 565 73 431 785 815

Small/Med Long top tube 550L 480 70 515 144 590 72.5 431 785 815

1730 to

1835mm Med/Large

Short top tube 580S 520 60 555 188 575 73 431 820 842

Med/Large Long top tube 580L 520 60 555 179 600 72.5 431 820 842

Large Short top tube

610S 560 50 595 214 585 72.5 431 850 865 1790 to

1905mm Large

Long top tube 610L 560 50 595 205 615 72 431 850 865

3

Mercury 700c

3

Issue 41 WINTER 2018

Finish

The Mercury frames and the THORN steel forks. have a multi stage finish. The tubes are treated internally, with a rust inhibitor. The outside surfaces are sprayed, with a rust-inhibiting primer. The frames are then sprayed with Twin Pack Aircraft paint - Du Pont’s Imron. The decals are applied and a clear coat or Imron is applied over them. The decals are effectively “sealed into the finish” and you couldn’t pick them off if you wanted to. Imron is a twin pack polyester paint - it’s very resistant to chips and has excellent adhesion.

The Mercury frames are finished in

4 different designs. See page 6

Gunmetal Imron, this is our most popular colour. The Gunmetal

colour has a very deep lustre. I’ve used black decals, so it’s a semi-stealthy finish. It doesn’t shout at you but you can read that it’s a Thorn Mercury - although only when you get up close.

Blood Red Imron, this is a new colour and it has silver and Black

THORN decals. On Page 5 you can see that I tried this colour out myself in the last batch.

Cobalt Blue Imron this is a new colour and it has silver and

Black THORN decals. This is gorgeous.

BRG Retro Imron, this is another very tasteful and elegant

finish. The gloss Racing Green frame has a painted ivory head tube and ivory snooker cue points painted and stencilled on the top and down tubes. The seat tube has ivory Celtic bands, with an ivory zigzag between them. Discrete green and clear “Thorn” and “Mercury” decals are positioned under powder lacquer, on the ivory points. A stainless “Thorn” head badge is fitted to the head tube.

There MAY still some stock in some sizes of the following outgoing colours:-

White Team, this is a flashy, in your face finish.

The intense white frame has red, white and blue decals on every tube. The decals are sealed in under a gloss powder lacquer. A stainless “Thorn” head badge is fitted to the head tube. I designed this finish to look special for the rider - it certainly brings a smile to my face.

Sky Blue Team, this is a very flashy, totally in

your face finish. The “Thorn Sky Blue” frame has red, white and blue decals on every tube. The decals are sealed in under a gloss powder lacquer. A stainless “Thorn” head badge is fitted to the head tube. Note, the “Thorn Sky Blue” is actually a cross between sky blue and duck egg green, it is reminiscent of the under wing colour used on WW2 Spitfires - this effect is only enhanced by the use of the red, white and blue decals! Fiona calls hers WRAAFA

Black Retro, this is a very tasteful and elegant finish. The gloss black

frame has a painted ivory head tube and ivory snooker cue points painted and stencilled on the top and down tubes. The seat tube has ivory Celtic bands with an ivory zigzag between them. Discrete black and clear “Thorn” and “Mercury” decals are positioned under powder lacquer, on the ivory points. A stainless “Thorn” head badge is fitted to the head tube.

Stealth (matt black), this is black powder with a matt powder lacquer.

The frames have micro sized decals under the base of the down tube, where they can’t be seen. We supply the bike with 2 self adhesive stainless steel “Thorn” head badges. You can decide whether you fit one of them or not.

I’ve designed a new mini eccentric for the

Thorn Mercury. I wish to state clearly that

there’s no intention of offering this on any of

the other models.

In order to actually save weight, the eccentric had to be smaller in diameter. Being smaller in diameter means that it can only adjust a little more than half a link of chain. When no more adjustment can be made with the eccentric, a new chain must be fitted. By choosing one of the ideal chain ring and sprocket combinations, the service life of the chain is maximised.

I believe that customers, who require a

sports bike, will be prepared to replace the

chain. Such cyclists will certainly find

obtaining and fitting a replacement chain

and servicing the mini eccentric, easier than

the expedition cyclist. Servicing and

preparing the bike for an important event

ought to be normal practice.

The 4 x M5 screws need to be tightened and loosened in a particular sequence, please see diagram. As soon as each screw becomes tight, each screw must only be turned a sixth of a turn (60°) at a time until they are tight. Experience has now shown that the mini EBB screws don’t need to be very tight, to prevent the eccentric from turning. 5 Nm is more than sufficient and there is zero chance of shearing a greased M5 screw at this torque. The screws must be removed at least every year and fresh copper slip must be applied to the threads. If the bike is used in harsh conditions, such as on salted roads or beaches, re-lubrication, with copper slip, must be more frequent.

The KMC Rohloff specific chain, which we now

fit to all Mercury bikes, is the best you can get - it

can be run for up to 1500 km before it needs to be

tensioned and it will last many times longer than any

other chain. In good conditions and if kept clean and

lubricated, the KMC chain ought to last 20,00km+

1

2 3

4

THORN

Tightening &

loosening

Sequence;

1, 3, 4, 2, 1, 3,

4, 2, etc.

Turn screws 60° turn at a time until

fairly tight - the maximum torque

of 5Nm is usually NOT necessary.

8mm ring

Then re-tighten screws in sequence

to secure the eccentric.

Once screws

are loose,

insert supplied

peg tool into

holes in the

eccentric.

Rotate the eccentric to

tighten or loosen the chain.

New THORN mini eccentric.

The peg spanner is supplied with the bike.

A B C

A has all adjustment remaining, B has half adjustment remaining, C has no adjustment remaining. Note that thin part of eccentric is at the bottom of the shell, to prevent ingress of water through the slots. Please see pic of alloy eccentric on the right to understand why this is so.

Size 550L

with Fork 2

4

Mercury 700c

4

Issue 41 WINTER 2018

Size 550L

with Fork 6

STEALTH

Size 610S

with Fork 3

GREEN RETRO

Size 550S

with Fork 4

Size 520S

with Fork 4

GUNMETAL

Size 550S

with Fork 5

These pics can be

enlarged to fill your

screen - if you have

the necessary kit.

NEW GUNMETAL IMRON FINISH.

Size 550S with Fork 5

Notice how different this rich colour looks in

bright lighting (above) and in shade (right).

BLACK RETRO

Size 550L

with Fork 4

The Avid BB7 cable disc brake (above)

has proved to be progressive,

powerful and completely reliable.

5

Mercury 700c

5

Issue 41 WINTER 2018

The 2 extremes of Mercury builds are shown on the front cover - here’s something in between. These bikes belong to Fiona and myself - they were perfect for our September 2013 holiday in the French Alps. We were in France for 20 days and, in that time, we managed 14 big alpine rides. We lost a few days driving there and back and a few more relocating our base camp. These bikes have been touring in Northern Thailand twice (which made the Alps seem easy), Cuba once and Southern Thailand since then - they are still brilliant!

6

Mercury 700c

6

Issue 41 WINTER 2018

Here are the 4

different colour

options for 2018

Here are

some

customers’

Mercuries

that we’ve

custom built.

Some of

these set

ups are very relaxed –

others are quite sporty.

COBALT

BLUE

IMRON

BLOOD RED

IMRON

BRG

RETRO

IMRON

GUNMETAL

IMRON

7

Mercury 700c

7

Issue 41 WINTER 2018

Here you can see 4

of our current

Demo bikes.

They all have Long Top Tube frames. You can make an appointment to take one out on a test ride. I’ve specified them all with 700 x 32c Schwalbe Marathon Supreme tyres and as few accessories as possible. The idea being, to demonstrate how light and quick a Mercury can be. I’ve shown them all at exactly the same scale on this page.

Our other 2 current Mercury Demo bikes can be seen on the front cover.

The plan is to be able to adjust one of these bikes to enable 95% of customers to test ride a Mercury. In order to facilitate this, we’ve left the fork steerers longer than we’d need to, with the majority of Mercury builds.

If you’re exceptionally short, or tall - we can’t supply you with a Mercury but one of our other Rohloff bikes will almost certainly fit you.

Andy Blance May 2016

Size 580L

BRG

Retro

Size 600L

Gunmetal

Imron

Size 550L

Sky Blue

Team

Size 520L

Stealth

Fork 7

Fork 2

Fork 5

Fork 4

Since MAYDAY 2016, we’ve offered to fit any

tubed Schwalbe tyres that you fancy at no upcharge. We’ve also fitted a variety of

Schwalbe’s new TUBELESS tyres, with suitable

rims as an upgrade.

The Tubeless Tyres are fantastic and you can read my report on them on pages 36 and 37 of the Mega Brochure and see the upgrade prices on page 85.

Also since MAYDAY 2016, we’ve been supplying

Rohloff hubs fitted with the new SPLINED

SPROCKET. This makes changing sprockets very

easy and will also allow owners to change their gearing very easily, particularly as there are many more size options available.

In the style we’ve become accustomed to with Rohloff, this mod is retro-compatible.

The splined sprocket carrier fits in place of the screw on sprocket, meaning that this modification can be carried out quickly, cheaply and easily on every Rohloff hub ever made.

Unique and exclusive to THORN

We’re so confident that we have built the wheels perfectly that we give a 10 year warranty on the Hub Flange of all of our Rohloff equipped bikes with 32 spoke hubs. This is for the original owner and is dependant upon you ensuring that ROHLOFF spokes are used if ever you need to have a spoke replaced.

Of course our wheel building is so good that it’s highly unlikely that you’ll break a spoke whilst cycling - no matter how hard you ride or how many miles you clock up. However accidental damage whilst touring is always a possibility. We now supply all of our bikes with spare spokes - make certain that you at least take your Rohloff spokes with you on tour. Andy B. Autumn 2017

© Copyright 2018 - All rights reserved.

St John Street Cycles Ltd - Thorn Cycles Ltd. Company no. 123142 VAT no. 406 7053 70

WHITE TEAM

Size 580L

with Fork 7

This is my bike, it’s so quick...I just love it! AB 2011 This bike now has a Thorn 853c fork, calliper front brake and S-One Tubeless tyres ...it’s even quicker and I love it even more! Andy May 2016

SKY BLUE TEAM

Size 550S

with Fork 7