Tyre width maximum on Thorn Sherpa?

[Vintagetourer]

I am keen to know if a Thorn Sherpa with CSS Rigida Rims will be able to accommodate 26"x2.25" (57-559) Marathon Extreme tyres? Or are they too chubby?

I am trying to decide whether to fit 2.0" Duremes or 2.25" Extremes for a long ride on rough dirt roads.

Any tried and tyred suggestions or experiences to share would be appreciated?

Graham Smith
Canberra Australia

[Danneaux]

Hi Graham!

These threads may prove helpful:
http://www.thorncycles.co.uk/forums/index.php?topic=3914.0
http://www.thorncycles.co.uk/forums/index.php?topic=5945.msg34143#msg34143

Is your Sherpa a Mk2 or Mk3? The "3" has a bit wider allowable tire clearance, up to 2.15" with mudguards according to the brochure.

Will you be running mudguards as well?

Remember, wider tires are also taller in profile, so -- especially if running mudguards -- the mounting bolt under the crown would make clearance tight. You'll also need to allow for mud collection and the occasional wheel wobble due to a broken spoke or damage.

[EDIT: I found an instance on the Forum of 2.25" Marathon Extremes used on a RavenTour without mudguards, which bodes well for a Sherpa: http://www.thorncycles.co.uk/forums/index.php?topic=3723.0 It is Magnus on his tour of Iceland. Photos here show the clearances: https://www.facebook.com/media/set/?set=a.10150263556849389.330677.597284388&l=d7251409e6&type=1 ]

I'd suggest an email to Thorn for the definitive word, being sure to note which model Sherpa you own.

Hope this helps.

Best,

Dan.

[Vintagetourer]

"I'd suggest an email to Thorn for the definitive word, being sure to note which model Sherpa you own."

Thanks Dan. I have done this and have received some very sound and prompt advice with a number of helpful suggestions.

At a pinch, yes I could run them but it is probably not the best choice given the heavy loads we will have on at the start of the ride.

Instead I will fit the narrower 2.1 Smart Sams which will be better for the type of dirt roads on this tour.

[Danneaux]

Thanks very kindly for the report back from Thorn, Graham. Since this topic arises on the Forum from time to time, the information will be very helpful to others in future.

Reviews of the Smart Sam over at MTBR show 22 reviews resulting in a 4.5/5 rating for what appears to be a fairly aggressive all-'rounder: http://www.mtbr.com/cat/tires-and-wheels/tire/schwalbe/smart-sam/prd_412701_151crx.aspx

If you go with these, it'd be wonderful if you could later offer a short report on how they fared on your long trip.

I use 2.0 Duremes myself, and find them to be good all-'rounders, excelling at no particular task but doing well across the spectrum of my cycling. That said, the tread is fairly shallow and I don't think it would be nearly as good a choice on lots of dirt and possibly mud as the more aggressive tread pictured for the Smart Sam.

Very best wishes on your long trip; may it be enjoyable and filled with the "right" kinds of Adventure -- the sort that makes for great stories but no real inconvenience or danger.

Best,

Dan.

[Vintagetourer]

Dan I think I would be probably OK with any of the following:

Duremes, Extreme, Mondial, Nobby Nic, Smart Sams or just about any reasonably robust tyre with at least a few nobbly bits on their shoulders.

What swung me toward the Smart Sams (after receiving advice from Thorn) is that 95% of the ride will be on unsealed road with quite a bit of it being sandy, corrugated with patches of sharp, loose gravel. The key factor though is that our loads will be medium to very heavy depending on water loads.

What swung me away from the Extremes is that their sidewalls tend to roll or flex too much under a heavy load. They'd be excellent if we were travelling a bit lighter.

I was actually also tempted to put on a Nobby Nics as I have found them to be excellent on my MTB. Once again, uncertainty as to how they'd stand a heavy load with their supple sidewalls.

I should say that Marathon XRs would also possibly be OK, but I took mine off after just 1500km of use. Their sluggishness just got too annoying.

My favourite tyre on the Sherpa are Supremes ... but not for 700km of unpredictable dirt and sand.

And yes I will definitely report back post-tour with a link to a CGOAB journal.

The ride is a fairly well known one, "The Gibb River Road". It is in Western Australia. Up north... close to Indonesia.

The hardest part is actually getting to it. It is about 4200 km of driving (or riding for the hardy and courageous) just to reach the tour area from where I live in S.E. Australia.

[mickeg]

You did not say if you use fenders or not.

I run 2.0 width Dureme in the front and 2.0 width Extreme in the back but I use fenders.  The limiting factor is the little bolt that holds the front fender into the fork crown.  While a bigger tire may fit, it would be pretty tight if a twig got stuck in between the tire and fork crown.

There is a lot more room in the back, I have run a pretty fat tire without a problem but have not tried the 2.25 Extreme.  I suspect that a 2.25 Extreme would work on the rear with or without fenders.

But I would not attempt a 2.25 Extreme it in the front if you use fenders.  I have not tried that specific tire, but I did try a larger tire in the front and decided it did not look too safe to me.

The Extreme is pretty noisy on pavement, Dureme is less so.  I use the Extreme on trips where I will be off pavement most of the time.

[Vintagetourer]

"You did not say if you use fenders or not."

I do usually but probably won't on this tour. Not sure yet, but I am tempted to take them off for this trip.

We are expecting it to be 100% dry road, so mud should not be an issue. Dry grit and sand could however be an issue, so mudguards (fenders) could be helpful to protect the drive chain.