larger tyre up front on Mercury Mk3

[strictnaturist]

Hi folks
I'm heading over to Canada (from Scotland) this summer, to ride south for around 1000miles to Jackson, Wyoming on the Great Divide route with my son. Camping all the way. I'll be on my 6 year old  Mercury Mk3. My son on my old Sherpa.
A few adjustments to my Mercury for the ride will be dropping the gears from a 43 x 19 set up, to 39 x 19 and switching from slick 2.00 tyres to the largest gravel tyre I can fit. Guidance for largest tyres on the Mercury are 54 mm. The front fork looks like it has clearance for a larger tyre.
Can I ask? If it fits, Is it worth having a larger tyre up front? The route is predominantly tracks/ off road.
As an over 60, I have only ever used inner tubes. Is it worth switching to tubeless at this late stage? Or stick to what I know?
Any recommendations for tyres?
Thanks, as ever, for your comments and all round knowledge.
Eddie

[PH]

I'm assuming from those numbers that it's 650B?  I think it would need to be pretty extreme before you noticed any benefit going over 54mm, that's already a lot of air, more than in the Sherpa. My Nomad on 650B 50mm tyres offers a very plush ride over just about anything I'd tackle. I'd be concentrating on the right tyre for the tour, rather than the width.  I know nothing of tubeless, I am curious to try, but for me it'd mean changing rims which I'm in no hurry to do.
Have a great trip.

[JohnR]

I can't think of a good reason for putting a bigger tyre on the front than on the back. In fact, I've done the opposite and put a slightly smaller tyre on the front on the basis that it carries less load than the rear tyre.

I was almost 70 when I first encountered tubeless bike tyres and am now a convert. A key requirement for a good tubeless experience is tubeless-ready rims. A good tyre-rim combination can be inflated with a simple pump. A poor combination results in much cursing and the need for a pressure tank. While tubeless tyres handle small punctures well, the ability to prevent a flat caused by a bigger cut is less certain and depends on the cut size and sealant. I've had one ride-stopping cut in ~20k miles which was caused by a flint shard. Attempts to plug the hole were unsuccessful so tyre boot and inner tube were needed.

[Andyb1]

Think of motorbikes John, most have bigger front wheels.   The same thing is happening with MTBs.  The term mullet applies.
I usually fit a larger section front tyre run softer than the rear to give some ‘suspension’ when hitting bumps.  My logic is that the front wheel is pushed down onto bumps while the rear is more likely to get pulled over them.
Also if hitting soft sand, a wider front tyre should be more stable.

[WorldTourer]

I'm heading over to Canada (from Scotland) this summer, to ride south for around 1000miles to Jackson, Wyoming on the Great Divide route with my son.

The GDMBR tends to get talked about today as more daunting terrain than it is. Once the bikepacking scene took off, it embraced this route which meets the Bikepacking.com definition because it is majority unpaved. However, before that, the GDMBR was commonly regarded as a touring route and people rode it on conventional touring bikes like the Surly LHT, with 2.00" or 2.15" tires. Loads of blogs were written about this, some of them are still up today. So, if you can fit 54 mm, you’re already well prepared, even if you might want to take advantage of being able to fit something slightly wider in front.

[mickeg]

Stay with tubes. 

For touring, I drop my gear range down to 36 chainring and 16T sprocket.  That is very similar to your 43 and 19 ratio.  If it is too steep for that gearing, it also is too steep for me to pedal while keeping my heart rate in a reasonable range.  Thus, I get off the bike and walk it up the steeper hills.

Have you ridden much on rough trails before? 

[strictnaturist]

Thanks for your swift comments
To answer. Yep. I have done a few tracks in Scotland.Green routes in Europe and across Iceland. All mostly on the Sherpa.
I'll drop the gearing for the Mercury to assist.
Sounds like 54mm tyres should be enough on the Divide trail.
I'll investigate what tyres would be best. Comments welcome :-)
Still swithering about tubeless though?
All best wishes
spring is coming!
Eddie

[mickeg]

Thanks for your swift comments
To answer. Yep. I have done a few tracks in Scotland.Green routes in Europe and across Iceland. All mostly on the Sherpa....

If you have been across Iceland, I assume you rode on the interior 4X4 roads when you say "across", then you should not have any difficulty riding the Divide.

[strictnaturist]

aye. up the west coast and down through the interior. Fully loaded Sherpa with a weeks supplies. Including box of wine and litre of duty free single malt . Just in case I met anyone :-)

[mickeg]

aye. up the west coast and down through the interior. Fully loaded Sherpa with a weeks supplies. Including box of wine and litre of duty free single malt . Just in case I met anyone :-)

Box of wine???  Bike touring, you are supposed to carry the dehydrated stuff.

Been there, done that.

[strictnaturist]

great stuff. Keeps the spirits up :-)

[Moronic]

Sounds like a great trip coming up! I've a 650B Mercury Mk 3. I've run Schwalbe G1 tubeless and Rene Herse Switchback Hill with tubes, both in 48/50mm. My routes are usually rough bitumen and smoothish dry gravel.

If you're not used to tubeless I'd say stick with tubes, unless you're expecting lots of thorns (lower case t) on the route. And even then you could put sealant inside the tubes. I found there was a bit a learning curve for running tubeless, and I wouldn't want to be doing my learning on a long tour.

First, they're hard to get seated on Thorn rims with a hand pump. If not impossible. Second, before the G1s lost all their tread, their sidewalls had flexed so much that they began to leak air, and fast enough to go flat overnight. Of course at that point you can simply add tubes. But that means fooling with lots of gooey sealant, and you still need to carry the tubes (and spares).

I put tubes in the Rene Herse tyres because they wouldn't seat on the Thorn rims even with a compressor. The ride with tubes still feels better than with the G1s tubeless, but that could be confirmation bias.

If I were embarking upon a long gravel trip I would probably go for the 48mm knobbly RH Juniper Ridge, so that I had good grip on wet gravel. I've not tried the 55s and I'd be concerned about clearance to mudguards. Also, they're heavier. I'd expect the 48s with 30psi in them would handle just about anything.

I like the RH tyres and they seem to last pretty well. But there are a lot of good and cheaper alternatives out there.