Mercury (700c) self-build

[edavey]

Hi there,

I've recently put together this Mercury with 700 wheels.

It rides very well, excellent handling on steep lanes.

As I've only built bikes of 80s and 90s vintage in the past, and due to the Rohloff hub, this build introduced me to various new bike parts:

Eccentric bottom bracket

This works very well for taking up the slack in the chain. I'm glad I've got the full-size eccentric as I think I would have struggled with less than the full link of adjustment I had available.

Rohloff

I'm using 35mm tyres on 700 wheels with 165 crank. My old 21-speed bike had gearing of 23.8 gear inches on 28/32 to a highest of 93.2 gear inches on 48/14.  For this Rohloff I'm using a 45T chainring and 19T sprocket for a range of 18 to 94.4 — ie. a similar high gear but with 2 lower gears at 18 and 20.

Cabling up the grip shifter with the External Cable Box took a bit of time. I ended up doing it twice as I needed to shorten the cables once I fitted the headlight -- so am now pretty confident that I could do it on the road if necessary...

Disc brakes

I've never had disc brakes before so this was new, though very straightforward to set up and once I figure out adjustment mechanism.

Threadless headset / steerer

Having to cut the steerer to length to suit my handlebar height was a new experience. I cut it a little long and fitted a 3mm spacer on top, just in case I was a little off with the measurements or wanted to try a more upright position in the future.

Dynamo lighting

This was a little fiddly -- neat cabling seems almost a contradiction in terms. The SON leaflets could have done with some more illustrations in my opinion but there were plenty of spade connectors and heat-shrink insulation supplied. I might upgrade to a coaxial plug connection in the future if disconnecting the spades when taking the front wheel on an off proves difficult.

I had some trouble getting the headlight set up in a position where it doesn't interfere with the front V-brake cable and "noodle" holder.

[PH]

Welcome to the Mercury club, you've put together a very distinctive looking machine, hope it does everything you're hoping for. 

Cabling up the grip shifter with the External Cable Box took a bit of time. I ended up doing it twice as I needed to shorten the cables once I fitted the headlight -- so am now pretty confident that I could do it on the road if necessary...

I can't imagine you'll ever need to, when they start feeling a bit stiff it's an indication they need changing in the next six months or so...

Dynamo lighting
This was a little fiddly -- neat cabling seems almost a contradiction in terms. The SON leaflets could have done with some more illustrations in my opinion but there were plenty of spade connectors and heat-shrink insulation supplied. I might upgrade to a coaxial plug connection in the future if disconnecting the spades when taking the front wheel on an off proves difficult.

Yes it can be fiddly, depends how fussy you are!  I heat shrink the rear light run to the brake cable, that's as neat as I can get it and I'm still not happy!

I had some trouble getting the headlight set up in a position where it doesn't interfere with the front V-brake cable and "noodle" holder.

Looks like you got there, though if it doesn't prove satisfactory, an alternative is to use the Brompton bracket and go under the link wire.

I was out on mine yesterday, first time in over a month!  A short but lumpy Audax, a great Autumn day to be out and a great bike to be out on.

[edavey]

Thanks PH,

Very I'm v happy with the ride and will the hub gear. I'm delighted not be having to clean the cassette after every mucky outing!

Heat shrinking the lighting cable to the brake cable sounds like a nice solution.

I've had 4 proper weekend day rides so on the Mercury, between 55 and 90 km, all with plenty of climbing, mainly quiet lanes and some gravel/paths. I'll ride throughout the winter though not in the rain if I can help it. Next year I hope to do St Malo -> Montpellier with light panniers, staying in B&Bs....

[mickeg]

...
Having to cut the steerer to length to suit my handlebar height was a new experience. I cut it a little long and fitted a 3mm spacer on top, just in case I was a little off with the measurements or wanted to try a more upright position in the future.
...
...
I had some trouble getting the headlight set up in a position where it doesn't interfere with the front V-brake cable and "noodle" holder.

I usually leave the steerer tube quite long, some of my bikes have a stem upside down so that the high steerer tube does not show as much.  Do not worry about that.  Some pros leave a small amount of steerer above the stem with a spacer so that the stem grips all of the steerer tube evenly.


I attached a photo of my Lynskey, I used an extra long B&M bracket and some big tools to bend it to fit exactly what I wanted.  So, you won't find a bracket exactly like mine, but it gives you an idea of what is possible.

And the second photo I attached is my road bike, it shows an off the shelf B&M bracket that I used to mount my headlamp, the bracket goes under the caliper brake.  I do not recall the B&M part number of this one, but it is easy to find with a catalog.  I think there are two brackets that are nearly identical with the same general shape.

[edavey]

thanks, those photos are very clear -- I hadn't thought of going under the wire -- which makes a lot of sense!

[PH]

I do not recall the B&M part number of this one, but it is easy to find with a catalog.  I think there are two brackets that are nearly identical with the same general shape.

I think that's the same bracket as mine, there are several similar designs, I don't know the part numbers either, but it's usually easiest to find in the UK labeled as a Brompton bracket.

[mickeg]

Ok, I looked it up, I have a 2020 catalog on my hard drive.  One page attached.

Mine is either the 474DU or 475DU, I am not sure which, the dimensions are different.  I am guessing mine is the 474DU but I could be wrong.

[UKTony]

Heat shrinking the lighting cable to the brake cable sounds like a nice solution.

The previous owner of the Mercury I bought last year used heat shrink tubing for this purpose and it looks pretty tidy to me. I think it might be unshrunk. It’s a snug fit and can be slid to and fro to adjust positioning  if necessary.

Enjoy the Mercury experience!

[edavey]

Ok, I looked it up, I have a 2020 catalog on my hard drive.  One page attached.

Thanks! I might see what I can do bending a long bracket. I'd like the avoid the light spilling on the mudguard if possible...

[edavey]

The previous owner of the Mercury I bought last year used heat shrink tubing for this purpose and it looks pretty tidy to me. I think it might be unshrunk. It’s a snug fit and can be slid to and fro to adjust positioning  if necessary.

Thanks for those photos. Yes, looks good, I've got too many ugly and sharp cable ties at present!

[mickeg]

Ok, I looked it up, I have a 2020 catalog on my hard drive.  One page attached.

Thanks! I might see what I can do bending a long bracket. I'd like the avoid the light spilling on the mudguard if possible...

I used the longest B&M mount available to bend for my Lynskey.  I used a big vice and a 400mm long adjustable wrench for leverage, the B&M wire mounts are very stiff wire.

[edavey]

I used the longest B&M mount available to bend for my Lynskey.  I used a big vice and a 400mm long adjustable wrench for leverage, the B&M wire mounts are very stiff wire.

Nice -- I had to do a fair bit of persuading on my mount! In other bending news I was pleased with how the brackets for my Thorn Expedition rack turned out:

[PH]

I'd like the avoid the light spilling on the mudguard if possible...

It does on mine, it's something I thought would bother me, but it doesn't.  I'm out on the Merc tomorrow, I might take some photos to add.