Mercury Mk 3 Tyre Choice

[SteveM]

I have a Thorn Mercury Mk 3 Rohloff 2021 Model with ST front forks, front Vs and rear disc.  It came with 700 x 38c Shwalbe Marathon Plus road friendly tires on DT Swiss tubeless ready rims.

I need something a suitable for some easy off road/on road - all rounders - for light touring and bike packing.  I have muddies fitted and like them in the Winter. 

Just wondering what is the best tire for me.  I'm thinking Shwalbe Marathon Plus Tour might be the best option and offer more grip on the gravel.  Not sure what the maximum tire size is for the Merc with muddies.  Anyone tried the 700 x 40s - would they fit or should I stick with 38c? 

Would you go tubeless?  Seems a lot of trouble when a spare tube is so easy to change on the trail.

The wisdom of this Forum is beyond belief, learning so much.  Thanks everyone.

[PH]

Welcome to the forum, nice looking bike!
Let me start by saying I detest Marathon Plus tyres, you'd have to pay me to use them and however much that was I guarantee at some point I'd consider it wasn't enough.  Plenty of people do like them, no reason we should all agree, it's just if we have a different opinion on that it's likely we'll disagree on other tyre preferences.
Grip on gravel, and any other hard loose surface, will be almost entirely dependent on the tyre's width and pressure.  Tread and compound will play such a small part as to make no noticeable difference.  Anything softer, mud and the like, needs a tread that is not only deep enough to get traction, but also spaced wide enough to clear it, as in knobblies, is that what you meant by "muddies" if so what tyres are you using?
Your Pluses are probably 40mm (700 x 38c) that's probably close to the widest you'll fit with enough clearance for guards (Hard to be certain, the rims and guards make a difference). The sort of minimal tread on touring tyres is largely for show, it might make a marginal difference through leaf mulch or a thin layer of mud over tarmac, but I can't say I've ever really put that to the test.  I can't see the difference between your Plus and the Touring Plus to be worth changing for.
If I were thinking of doing more off road on the Mercury, I'd be looking at tyres with smooth centre sections and side knobs.  Something like the Hurricane from Schwalbe which comes in 42mm (Which may or may not fit) or the Double Fighter from Continental which is available in 37mm which I'm pretty sure will fit. I've used and been happy with both those tyres, though not in those sizes and not on the Mercury.
Of course as soon as you mix mud with mudguards you run into clogging issues, the more traction the tyre has, the more mud it's going to try and drag around, I doubt there's a combination on the Mercury, with 700c wheels, that gets around that.

[JohnR]

I also had some Marathon Plus Tour tyres which I recently gave away to a friend to use for commuting. They have thicker rubber than normal Marathon Plus tyres and will take an eternity to wear out but I don't think they offer better grip.

My ex-demo Mercury which I bought in mid-2020 came with 50mm Schwalbe G-One Speed tyres which were set up as tubeless although the Thorn rims weren't proper tubeless-ready. I was worried about punctures and stocked up with a spare tube, some plugs and a small bottle of sealant but more than 10,000 miles later have yet to have a ride-delaying puncture. When I changed to tyres with more grip for the winter (Gravelking SKs) I found that there was little sealant remaining the rear tyre and evidence of several small holes (thorns?) which the sealant had plugged. The Mercury frame will take at least 50mm rear tyres with a suitable mudguard but your forks may provide a limitation on the maximum front tyre size (my Mercury came with the Thorn disc fork which had plenty of clearance). There's very little difference between 38 and 40mm tyres and you should be able to look at the current tyre-mudguard clearance and tyre-forks clearance to see if larger section tyres will fit (in theory a nominally larger tyre will be both wider and higher off the rim but the actual shape is influenced by the rim width).

If you've got tubeless-ready rims then I reckon you should try tubeless. There's a large range in the Schwalbe G-One family. I'm currently using G-One Allround tyres https://www.schwalbe.com/en/gravel-reader/schwalbe-g-one-allround for some extra grip on the mucky winter roads while the G-One R claims to be good over a wider range of conditions https://www.schwalbe.com/en/gravel-reader/schwalbe-g-one-r. Or the are the Gravelkings although I found the SKs to be noisy on smooth tarmac while the G-One Allround tyres are quiet.

Merlin Cycles has a good range of potentially suitable tyres at attractive prices https://www.merlincycles.com/cyclocross-gravel-tyres-75333/ so you should be able to find something to try without breaking the bank.

[mickeg]

I have never tried tubeless and I doubt that I ever will.  That said, if you want to try it, go ahead.  It is my understanding that tubeless tires and the rims should both be rated for tubeless if you go that route.  But I will leave that up to you to research.

I am not familiar with the Mercury, but I have toured on 700c X 37mm wide tires.  At this time the model of tires on my light touring bike are no longer made so I won't suggest something that you can't buy.  I have bought some Mondials to replace those tires when they are worn out, in 35 or 37mm width (I do not recall which).  The Schwalbe Marathons (with green guard) would be another option too.  I have used the Marathons (with green guard) on a 26 inch touring bike in 40mm width, was very happy with them.

I do not know what you mean by off-road, if it is well maintained gravel and dirt, I would think that almost any tire that has some tread would work well.  If you are riding in mud, I have no suggestions, as I have tried to avoid that. 

I mostly agree with Ph, I have not used the Plus tires because of their reputation for being quite slow.

There are so many brands and models of bike tires, that I can't keep track of most of them any more.

[SteveM]

Thanks for the replies folks, really useful.

Muddies = mudguards!  Sorry for trying to sound cool (a definite fail).  I have a pair of Marathon G-One All Around tubeless but the guy who sold me the bike (the very lovely Ray) did not get on with them and had repeated flats.  That may have been sealing issues, but I am loath to put them back on if they are going to be problematic. 

Thanks for the advice on the Tour upgrade - I will save myself around £75 and stick with the Plus 38c tires and see how they go on light gravel.  I have absolutely no love for mud plugging but I do like a well maintained gravel road.  I live in Wiltshire and the Salisbury Plain perimeter path has good gravel.  I will see if the Marathons can cope with that.  The Mercury is promoted as a potential gravel bike so it should cope OK.  I prefer routes with 70/30 quiet road to gravel.

Having studied the Thorn Bible and squinted between the Frame I think they are just about the biggest I can fit to be honest and the SJS supplied SKS mudguards are a bit too snug for comfort really - fine on the road but as you say probably a bit rubbish on wet slimey single track (which I avoid if possible).  I might just get away with a slightly wider tire but the height is the issue.

I had Marathon Land Cruisers on my last bike and they were a good all-purpose tire and I never had a puncture in two years.  But having got my hands on the gorgeous Thorn Mercury, I want to kit her out in the very best tires I can afford.  Tubeless is a bit of a mystery to me, but having watched Youtube, they seem like a good option on MTBs.  Maybe not for my mainly tarmac expeditions. 

The Merc can handle 30kg of luggage which is way more than I would want to carry tbh.  So, I think it will be perfect for my needs.  Its a light and responsive bike with a great range of gears on the Rohloff  It's a keeper!  Thanks Thorn, best bike makers on the planet for me.

[Moronic]

Edit: Steve I posted the below seconds after your post above, so despite appearances I am responding to your original post. 



Thorn recommends 700c x 40 in its brochure for the Mercury 700c, so we can safely say they will fit.

http://www.sjscycles.com/thornpdf/BUILD9MERCURY700cROHLOFF.pdf

You might fit something bigger but perhaps not with mudgaurds.

Lots of wisdom from posters above, and from both research and small experience I'll endorse what PH says about tread. For example, Rene Herse principal Jan Heine recommends the almost treadless version of his tyres over his knobbies for all dry gravel surfaces - argues that the tyre will be floating on top of the gravel and so knobs locate only with gravel, which offers no secure purchase. He does huge amounts of gravel riding and supplies tyres for racers, so he's earned his opinion. Knobs for if you think it will be muddy.

I'm running 650B wheels on my Mercury, with 50mm G-One Speeds (now have a Rene Herse on the rear). If you were planning a major shift to lots of gravel riding, a switch to 650B wheels would give you this extra width - Thorn says up to 54mm. The fork has reversible brake fittings so would fit 650b, but of course you'd need a second rear wheel with Rohloff or rebuild the one you have -  rebuilding to a different size can cause problems with hub flanges, I believe (do your own research there - that's just top of my head from something I read somewhere).

The 650B x 50 tyres feel great in dry gravel and the Merc steers beautifully in such circs. But plenty of gravel riders seem to run 700c x 40s and so likely that's all you'll need unless you're heading into mountain bike territory - in which case a Merc might fall short for other reasons.

Ideally on gravel you'd run a modern tyre with very flexible sidewalls and drop the pressure so that the tread spreads out and gives you flotation. Tubeless offers some protection against pinch flats at low pressures, but for gravel you likely would not need to go that low. Thorn recommends 48/53 psi for 40mm thres and 40/45 for 50mm. However I generally run 30psi in my 50s on gravel, which Thorn lists as a recommended minimum. Rec min for 40s is 35psi, and with a tyre such as a G-1 that's what I would be trying on gravel. No, you don't go any slower than when you have them up hard - I've rolled alongside enough other riders to be convinced on that front.

The thing I love about tubeless is that you can buy a Dynaplug system and fix most serious punctures in seconds and without removing the wheel or demounting the tyre. Minor punctures seal themselves, and the seal lasts as long as the tyre. Huge punctures that deflate the tyre fully will demount the tyre from the rim wall, and in case of those you still need to carry a tube because a portable pump won't remount the tubeless tyre after patching. Tubeless also saves the weight of the tube, but some of the saving is lost to the weight of the sealant.

[SteveM]

Thanks for the advice Moronic.  You are spot on as usual.  My SJS/Thorn supplied Marathon G-One All Arounds are tubeless 40s, so I might give them a chance.  The Shwalbe Marathon Plus are good tires and they do a great job - its the off-tarmac bits of my routes where they may be a bit skittish.  Its an adventure into the unknown for me, never ridden tubeless.  The rims are definitely hoooked and tubeless ready so that is no problem.  I'll talk to the guys in my local bike shop about sealants.  No more technical single track stuff anticipated for me - getting much more road orientated as I get older.  I'm a sightseeing tourist as much as a cyclist these days - but that's a whole different problem!  Securing a £4k bike and luggage while I wander around a cathedral is a stressy business!

[SteveM]

Update: the rims are DT Swiss R460 700c not 560.  https://www.sjscycles.co.uk/rims-tape/24-dt-swiss-r460-700c-622-rim-black/ 

[Moronic]

Steve if you have Schwalbe G-One Allrounds x 40mm as supplied by Thorn then this is a premium tyre for your application. It's a G-One Speed with deeper tread, which would give you extra security in wet sections when new. This is one of the modern tyres with flexy sidewalls I mentioned above. The sidewalls don't absorb much energy when they flex, so you can drop pressures with little speed penalty (if any, on bumpy surfaces - in fact over distance the lower pressures will likely bring a speed advantage it appears, from reduced rider fatigue). The G-One series was one of the earlier fast gravel tyres on the market, and while it now has plenty of competitors I'm not aware of anything that outperforms it significantly. For your intended use, since you have them already, a no-brainer.

As you're likely aware, you can pop tubes in them if you want to get a feel for them before committing to running them tubeless.

For clarity, these are made by Schwalbe, which also makes the Marathon series, but these are not Marathons, and so are immune from PH's reflexive avoidance. The Marathon series is aimed at commuters and long-distance tourers, and the tyres have thick tread caps and hard belts beneath. From all accounts they resist punctures and last a long time - I've not ridden on them, but have faith in PH's assessment (Mercury designer Andy Blance has made similar observations).

The G-One series is a performance gravel tyre. Thin tread cap, soft rubber, no special anti-puncture belt as far as I know. Fast, comfortable and sticky, but puncture-prone and short wearing. Short of the more costly Rene Herse, which is wedged even further into the performance end of the compromise set, they're about as good as you'll get for speed and all-weather grip on gravel. My guess that after the Marathons, you'll feel like you've developed suspension and a permanent tailwind. Let us know. 

[PH]

Steve if you have Schwalbe G-One Allrounds x 40mm as supplied by Thorn then this is a premium tyre for your application....
...As you're likely aware, you can pop tubes in them if you want to get a feel for them before committing to running them tubeless.

Yes this. I'd do as Moronic says, stick some tubes in and give them a go. I've never tried tubless, but I'll guess you'll get a good impression of the tyres without going that extra step. I note that Thorn originally supplied these 700 x 40 tyres tubless, then changed to using lightweight tubes, I don't know the reason.
I had the Allrounds on a E-bike used for delivery, all urban riding and their main attributes were wasted on that usage.  Had a couple of punctures and swapped them for something tougher and more appropriate for the job (And three times the weight, but I've got a motor!).  On a tour, or any other leisure ride, I'm less likely to get a puncture as I'm less likely to be riding 100's of miles a week on dodgy glass strewn surfaces and also, at my leisure, it's no more than a mild inconvenience to fix it.  When I was doing a 30 mile a day commute, half of which on cycle track, at least one way in the dark, to a time critical job, I used Marathon Plus. Tyres are about choosing the right ones for the application, IMO as much so as the bike itself.

For clarity, these are made by Schwalbe, which also makes the Marathon series, but these are not Marathons, and so are immune from PH's reflexive avoidance. The Marathon series is aimed at commuters and long-distance tourers, and the tyres have thick tread caps and hard belts beneath. From all accounts they resist punctures and last a long time - I've not ridden on them, but have faith in PH's assessment (Mercury designer Andy Blance has made similar observations).

Schwalbe confusingly attach the Marathon name to all their touring tyres, it's a wide range.  Some of my favorite tyres are Marathons, the Supreme and Almotion. Even the previous model of standard Marathon (Before the Greenguard) was a fine do-it-all tyre and I still have them on my Airnimal folder and the Brompton has Marathon Racers, though it's not going to race anywhere. It's only the Plus series I dislike, it is just my opinion of course, but they have no other attributes other than puncture protection and longevity.   When the commute mentioned above came to an end, I swapped the Pluses for Paselas, it was like a completely different bike. 

[mickeg]

...
For clarity, these are made by Schwalbe, which also makes the Marathon series, but these are not Marathons, and so are immune from PH's reflexive avoidance. The Marathon series is aimed at commuters and long-distance tourers, and the tyres have thick tread caps and hard belts beneath. From all accounts they resist punctures and last a long time - I've not ridden on them, but have faith in PH's assessment (Mercury designer Andy Blance has made similar observations).
...

I agree with PH, the "Plus" Marathons are the really slow ones. 

I am quite happy with my plain Marathons (with greenguard). 

I also am still using some Marathon Duremes and Marathon Extremes for bike touring, that I am quite happy with.  Since those are not made any more, I only put them on the bike for touring, take them off at the end of a tour to save them for later.

[SteveM]

Thanks for the amazing advice guys, really do appreciate it.  I will give the G-Ones a go and see the difference.

Happy downhills everyone.

[JohnR]

Off-topic for tyres but relevant for making the bike more winter-tolerant is to fit a Hebie Chainglider which will keep the drivetrain much cleaner and longer-lasting. Here's one relevant discussion http://thorncyclesforum.co.uk/index.php?topic=14229.0. However, one key constraint is having a chainring of suitable thickness and number of teeth to suit one of Hebie's standard sizes.

[Moronic]

Yes my ignorance on the Marathon range was showing above. Thanks guys for correcting the info.

Re Thorn going to light tubes with sealant as its recommendation over tubeless, the impression I got from bits of reading I did somewhere was that they found the lower volume tyres deflated too quickly for plugs to be an effective puncture repair in many cases. You need to have enough pressure remaining in the tyre for the tread to hold up under the point pressure of inserting the plug. You can't plug a tubeless tyre that has all but deflated.

Problem if you can't use a plug is you have to remove the tubeless valve and insert a tube, while dealing with sealant sloshing around in the tyre. Okay if it's a very rare occasion; silly if it's frequent.

Hence the suggestion of a light tube with sealant. Again from reading rather than personal experience, it appears the sealant works quite well to seal the tube against small penetrations - the tube after all is pressed against the tyre carcass by air pressure. I'd have thought the tube woukd tear, but apparently not. And then if a bigger puncture requires you to replace the tube, most of the sealant comes out with the tube amd the job is much cleaner.

I ordered my Mercury with 50mm G-Ones and Thorn supplied them tubeless with no recommendation for tubes. I've only had to make one repair on the road, and as it was a front tyre I coukd see it was holed by the sealant spraying gently from the tread. Easy therefore to find the hole, and with enough air pressure still in the tyre that it was easily plugged. My guess is that 700c x 40 would have enough volume to work this way also.

By way of contrast, I left the rear tyre sealant unreplenished for six months or so and one day picked up a small puncture that didn't make itself obvious on the road and yet didn't quite seal. The tyre deflated fully overnight in my garage, and I could not remount it with a garage-style hand pump. I added some sealant and took the wheel to my local bike shop, which mounted the tyre with a compressor. I'd taken plugs with me, expecting that leaking sealant would reveal the site of the hole. But the fresh sealant had immediately sealed the leak, and that tyre ran unplugged for several more months until tread wear led me to change it.

[JohnR]

The ease of inflating a tubeless tyre depends on the tyre and rim combination. While my Mercury came with tubeless tyres they were on Thorn 584 rims which aren't tubeless ready https://www.sjscycles.co.uk/rims-tape/32-thorn-275-650b-584-disc-rim-black. I had to get a booster tank to get 50mm G-One Speed tyres to seat on the rims but I completely failed to seat 48mm Gravelking SK tyres which were a slightly looser fit as the air was leaking through the gap between tire and rim faster than the blast from the air tank could get into the tyre. Extra rim tape was added into the central depression in an attempt to make a tighter fit but wasn't successful.

When I did another bike build I used wheels I already had which had American Classic Hurricane rims which had come with tubes but I discovered that they were tubeless-ready and fitting tubeless tyres onto those was easy. My latest bike fiddling uses Kinlin TL-21 rims which are ideal as the flat areas each side of the central depression slope very slightly towards the edges. Provided the tyre sits on those flat areas when initially fitted onto the rim then there's already a fairly good seal and the tyre can be easily inflated with a floor pump.