New Mk3 Mercury

[alexmac]

Yes I'm using it as supplied with the plastic shim. I might try the foil and/or grippy compound suggested above because I do find the p

My Mercury came a metal seatpost shim.

The bikes are so different that the spacings are totally different. I am at 'limit nose down' with the adjustment on the supplied Thorn seat post which actually feels like it should be about right but I would like the option to experiment by dropping the nose a bit more. I can't do that without buying a new post though since I don't have any spares knocking about.

The thought of having the saddle significantly away from the horizontal horrifies me. Why so nose-down? I would see this as a sign that the handlebars should be higher. If flipping the ahead stem doesn't raise the bars enough then other stems with more angle are available and relatively inexpensive.

My mistake, mine is actually metal too but just looks like black plastic.

Re the saddle, I prefer having the nose modestly down because I find it comfortable but on this frame and seat post 'maximum nose-down' is not radically off horizontal (see e.g. photo +5 above).

[JohnR]

My mistake, mine is actually metal too but just looks like black plastic.

Re the saddle, I prefer having the nose modestly down because I find it comfortable but on this frame and seat post 'maximum nose-down' is not radically off horizontal (see e.g. photo +5 above).

So it's probably the same shim and same batches of seat post and frame as I've got. I would suggest putting some layers of aluminium foil between the seat tube and shim.

If the bike has a different geometry then your body position and hence sit bone spacing will be different which would change the optimum saddle width (more upright = wider, more head-down = narrower).

[alexmac]

5-year update:

It’s a great bike. Some highlights for me after some miles…

1. As expected maintenance has been minimal. Regular maintenance is oil change a year which takes me about 30 minutes and then also brake adjustment and brake pad replacement when needed (which can be quite frequent if e.g. touring in mountains!). Irregular maintenance has been replacement of one broken rear spoke which was probably either a manufacturing defect or damaged somehow as it broke in very low-stress circumstances, and replacement of the cranks after bending one in a spill. I’m still on the original drive chain which I think is absolutely exceptional/astonishing - I would have replaced a derailleur drive chain several times by now with this mileage and these conditions. I make no attempt to clean the chain because the benefit of doing that seem so marginal - I just add some wet lube from time to time.

2. It still looks good! Cosmetically it is wearing well and even the rack is not showing much rubbing.

3. Generally it is a nice bike to ride and for my use as my single “bike for life” which does all things it is ideal. I haven’t made any other changes to it.

I only have a single spare Marathon Supreme tyre left and since they have been discontinued at some point I’ll have to change tyres which I’m a bit disappointed about because they are excellent.

[PH]

Glad you're still so happy with it, I feel the same about mine. 

I only have a single spare Marathon Supreme tyre left and since they have been discontinued at some point I’ll have to change tyres which I’m a bit disappointed about because they are excellent.

Schwalbe replaced the Supreme with the Efficiency, which they claim is their fastest ever touring tyre.  I was sceptical, it's a lot chunkier and doesn't look like it'll be a suitable replacement, in a blind test, I doubt I could tell them apart.
https://www.cyclinguk.org/cycle-magazine/review-schwalbe-marathon-efficiency

[macspud]

Hello Dan, 👋🙏👌
If you could have a look for a Mercury mk3 brochure too.
Its a shame that the history of Thorn Cycles is slowly disappearing. The historic brochures and the masses of historic posts on this forum, which are in many ways the living archives of Thorn history. The archives of Thorn Cycles lived history out in the world.🤔
I'm starting to dream of a future Mercury build.😄

Oops, I meant to post this in the historical archives thread.😳

[martinf]

I only have a single spare Marathon Supreme tyre left and since they have been discontinued at some point I’ll have to change tyres which I’m a bit disappointed about because they are excellent.

Also a fan of Marathon Supreme for on-road use.

I still have a reasonable stock, so no immediate need to find something else.

But one contender would be the Continental Contact Urban wire bead tyre. This is a bit heavier, much cheaper, and according to https://www.bicyclerollingresistance.com it is pretty much the same as Supreme as far as rolling resistance is concerned. I have Continental Contact Urban in the 16" size on two of the family Bromptons, so far the tyres have performed very well and seem to be reasonably puncture resistant.

[macspud]

I also have to carry mine up and down stairs every time I use it, but do so by the seat tube, have done so with every bike without thinking about it. 

Maybe I don't get what you mean but if I do this then I end up with my legs banging into the handlebars! But minor gripes indeed.

Needing to clamp the seatpost tight doesn't sound good, is it the standard Thorn one that came with it?  Mine don't need much tightening, if they did I'd be inclined to add a shim.

Yes I'm using it as supplied with the plastic shim. I might try the foil and/or grippy compound suggested above because I do find the post can end up lower after long and bumpy rides and the tightening makes me a bit nervous.

Have you positioned the saddle with exactly the same saddle to handlebar spacing, saddle to handlebar height difference, saddle slope and saddle top to crank centre distance as on the other bike? I would try flipping the ahead stem to raise the handlebars slightly.

The bikes are so different that the spacings are totally different. I am at 'limit nose down' with the adjustment on the supplied Thorn seat post which actually feels like it should be about right but I would like the option to experiment by dropping the nose a bit more. I can't do that without buying a new post though since I don't have any spares knocking about.

This may sound like a daft question but did you make sure that the shim gap lines up with the seat tube gap?
If not the shim has a very hard time closing down on the seatpost.