Author Topic: Thorn Sherpa Build  (Read 7542 times)

SteveM

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Thorn Sherpa Build
« on: January 27, 2023, 05:19:23 PM »
There is a nice Sherpa for sale on FB.  I was thinking of investing and completely overhauling it to make a modern heavy tourer.  Of course, that’s fine in theory but upgrading to mech discs and Rohloff are not really possible in my home bike shed are they?  I just fancy taking it apart completely and rebuilding with new components just so I can learn new skills.  I also fancy a decent heavy hauler.  Here is the link:

https://www.facebook.com/marketplace/item/8798144073560316/

What would you all do with this?

mickeg

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Re: Thorn Sherpa Build
« Reply #1 on: January 27, 2023, 05:59:46 PM »
I am content to stay with rim brakes.  I built up my Sherpa in 2010.  I have made some modifications from the original build, but I kept the drive train pretty simple.  A triple crank, eight speed cassette, bar end shifters on drop bars.  Works great.

I have three touring bikes, I have not ridden this one since 2017, but I would happily use it again for the right kind of trip.  Due to the pandemic, I have not done a bike tour since 2019, but am planning two tours.

PH

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Re: Thorn Sherpa Build
« Reply #2 on: January 27, 2023, 06:14:20 PM »
What would you all do with this?
It's a decent bike at a reasonable price, assuming all the components are in good usable order. It isn't IMO an outstanding bargain, if it isn't very close to what you want and you start swapping parts and modifying, it could quickly becomes poor value. 
if you want a bike to play with, I'd look out for an old school, rigid, steel, MTB, maybe something just into modern standards, 135 OLN and threadless fork.  Should be able to find something under £100 with plenty of potential to turn it into a usable tourer.
You mention heavy duty tourer and I'm not sure the Sherpa is. I had a Raven, which was pretty much the Rohloff equivalent, certainly a very capable tourer, not at the light end, but not at the expedition end either.  Though of course you can do most things on most bikes...

SteveM

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Re: Thorn Sherpa Build
« Reply #3 on: January 27, 2023, 07:09:20 PM »
Nice looking bike PH.  It’s kind of iconic in its full pannier set-up.

Thanks for the advice.  I could buy an old MTB to revamp but I just love Thorn bikes.  I have a Mercury which I love, but would like a more solid tourer that I can chuck at anything.

PH

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Re: Thorn Sherpa Build
« Reply #4 on: January 27, 2023, 07:28:44 PM »
Nice looking bike PH.  It’s kind of iconic in its full pannier set-up.
I think you may have mixed my post up with mickeg's.
But here's a photo on my loaded Raven from a few yeas ago.  They are good bikes loaded, I parted with mine as I wasn't doing much of that sort of touring.
loaded raven by Paul, on Flickr

mickeg

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Re: Thorn Sherpa Build
« Reply #5 on: January 27, 2023, 07:52:47 PM »
I think the Sherpa is rated for 30 or 35 kg of luggage, counting handlebar bag and water bottles.

I pasted this from the Sherpa brochure, page 7, brochure Issue 6, May 2009.
In the table above, you will notice that the smaller frames are made with Thorn 969
standard oversized tubing, these smaller frames are more resilient but will not carry
such a large all-up load, 20Kg is the maximum load at the rear and 8Kg is the
maximum for the forks.
The larger sizes are made from Thorn 969 extra oversized tubing, these are used to
keep the luggage carrying qualities, of the Sherpa, proportional to its size. These larger
frames are stronger but slightly heavier, they will carry in excess of 25Kg at the rear
and up to 8Kg at the front.


That FB one is likely a Mk I or Mk II. 

I had 31 kg on my bike on the trip where the photo attached is from, photo was taken about ten and a half years ago.  The bike handled the weight very well, no shimmy.  I have size 610S.

I bought my frame and fork in 2010 used from someone in Canada.  (I am in USA.)  He really liked the Sherpa but decided that he wanted a different size bike.  I am not sure how old mine is, I suspect 2008 or 2009.
« Last Edit: January 27, 2023, 07:56:26 PM by mickeg »

Danneaux

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Re: Thorn Sherpa Build
« Reply #6 on: January 27, 2023, 08:22:19 PM »
Hi Steve,

I find that Sherpa to be a nice looking bike...and agree with all Paul said about it in particular and the Sherpa generally. I owned a lovely Sherpa Mk2 and later rode the equivalent RavenTour on a long loaded tour, kindly loaned me by a friend. Now I own a Nomad Mk2. Having ridden all three, I'd say the Sherpa/RavenTour are good, solid heavy-duty touring bicycles. I found the upper weight limit for good handling in my estimation on rough roads to be about 25kg/56lbs of cargo. I just needed a sturdier machine for my expedition tours where the bulk of my weight is in water and food to sustain my solo back-of-beyond expeditions where I can't readily get to stores for resupply. By far, my biggest weight for desert touring is in water -- 26.5l, consumed at 8.5l/day.

That said, the RavenTour I rode (Sherpa Mk2 equivalent in most respects except for the Rohloff instead of derailleur drivetrain) was absolutely BRILLIANT on the exceptionally poor pavement and dirt tracks of Eastern Europe with four panniers, a HB bag and rear rack-top load (one-person tent and a solar panel there). I had plenty of capacity to carry a couple days' food and as much as 8.5l of water (needed each day in the heatwaves I encountered in Romania and Serbija) and it rode beautifully. I'd call it the ideal bike for my needs in those circumstances, just not for the extremes of expedition loads carried in equally extreme circumstance.

I had a gap in my stable for a derailleur bike with characteristics and weight somewhere between the Sherpa Mk2 and my Nomad Mk2, a sort of bikepacking oriented bike that would still feel lively with fat tires yet was capable of carrying a "heavy" but not extreme load in panniers on pretty poor surfaces. Keying off Paul's good advice, about 6 years ago, I picked up a 2007 Diamondback Transporter that had been a rental bike, then sold off through a reputable pawn shop. Cost me USD$135 and I removed the used drivetrain for use on another project, substituting a full nearly new Shimano Deore drivetrain and some wheels (one with a SON dynamo) I had built-up and had on hand. I prefer drop handlebars and wanted a more compliant fork, so I sourced two Sherpa Mk2 forks from SJS Cycles to get the ride I wanted and bring the handlebars up where I needed. One resulted in neutral handling with 57mm of trail, the other provides a relatively low-trail geometry at 40mm and I enjoyed the handling provided by the latter so much it has stayed in place. I prefer drop handlebars, so I left the steerer uncut and with a short 60-70mm stem extension and compact reach/short drop 'bars, my hands on the brake hoods are within 1mm of where they were on the original riser handlebars with a longer stem extension. It looks a but odd with its tall steerer but works brilliantly and as mentioned, my hands end up where they were before but oriented differently. The top tube looks and is low but mid-tube standover comes at the same place as it does on my Nomad. The crown race-to-dropout measurement on each of the Sherpa Mk2 forks dropped the head tube slightly, making it and the seat tube about 1.3° steeper. It really paid to research it all in advance and this of course affected resulting trail and which fork I sourced from SJS Cycles.

I later fitted some spares from my stock or sourced cheaply...front Tubus Duo and rear Cargo Evo from Craigslist bargains (our version of Gumtree) and bought and fitted a new Thudbuster LT sus-seatpost I got on a stacked sale (factory reduction + store reduction + some coupons and finally store credit...as I recall, it ended up costing me $35 out of pocket). Mudguards came from some rehabbed spares recovered with permission from the LBS trash skip along with new stays from PlanetBike.

The end result is what I call my "Enduro-Allroad" and performs brilliantly in its intended role; the all-'rounder of my fleet and one I find myself riding often because it is so versatile and pleasant. It came with some shallow dents and plenty of scratches thanks to its history as a rental bike, but none affect performance. I'd slot its performance as a tourer a bit above the Sherpa Mk2/RavenTour in terms of cargo capacity thanks to the enormous steel frame tubes, a 35mm top tube, 43mm(!) downtube, 19mm steatstays (same as my Nomad) and the compliance of the Sherpa Mk2 fork and TBLT seatpost. If I were to tour with a front-heavy load, I'd use the fork that provides 40mm of trail; with a rear-heavy or neutral load, I'd go with the 57mm of trail. Ideally, a rear-heavy load would have trail somewhere around 63-67mm. It is as happy with bags strapped to the frame.

Paul makes a very good point about how a seeming bargain often is anything but that once you get it personalized to your needs. If I hadn't already had the needed parts on hand (and a good place to put the ones I took off), the $135 I spent for what amounted to a frame only would have been the narrow end of the wedge toward spending upwards of USD$1,100+ more additional at online prices to get it working to my needs. So...a great project bike for me, basically a frame to hang parts I already had on hand, but something much "nicer" in appearance could have been had if I were spending retail. It also required a heck of a lot of work and thought to get everything working together; in the end I would probably has spent no more time cutting tube stock and brazing up a frame and fork from scratch (I'm a hobbyist framebuilder). The result works great, but it was in no way the integrated solution this Sherpa you spotted is, with all the geometry and basic parts designed to work together from the start. Andy Blance already did the hard work. Provided this Sherpa comes close to your needs, it could be a great bike for you but if it needs some things changed, swapped and upgraded here and there, then it'll get spendy real quick.

Best, Dan.

PH

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Re: Thorn Sherpa Build
« Reply #7 on: January 27, 2023, 08:34:41 PM »
I think the Sherpa is rated for 30 or 35 kg of luggage, counting handlebar bag and water bottles.
I know that sounds a lot, it's more than I'm ever likely to carry, and where you draw the lines is subject to your own interpretation.  The Sherpa is certainly heavy duty compared to Steve's Mercury!
I always equate heavy-duty as designed to do anything. The Sherpa had two heavier models above it at the same time, Nomad and EXP.  Thorn seem to have dropped the expedition level, maybe because the section of it not covered by MTB derived bikes is too small a market and best left to custom builders. I don't know, I'm just guessing. Even so, some of the current Nomad builds are rated to be 40kg+ and that's without bar bag and water bottles!

Danneaux

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Re: Thorn Sherpa Build
« Reply #8 on: January 27, 2023, 09:45:14 PM »
When making my selections and perusing Thorn's catalogs, I tended to think of the bikes in American car-truck terms...

If we go with one brand, then...
Ford Mustang = Early Thorn go-fast derailleur bikes like the Cyclosportif or Brevet
Ford F-150, 1/2 ton pickup, standard duty = Audax/Mercury
Ford F-250, 3/4 ton pickup, heavy duty = Sherpa Mk2/RavenTour, later the Sherpa/Raven series that were downgrade slightly
Ford F-350, 1 ton pickup, Super Duty = Nomad Mk2

Put another way, if my Sherpa Mk2 was a WRC rally car on rough terrain, then my Nomad Mk2 is a Kamaz rally-raid truck.

Others may differ but for me, these comparisons helped me visualize the relative handling qualities, weight, and payload/cargo capacity for each of the Thorn bikes at the time I was buying.

Best, Dan.

martinf

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Re: Thorn Sherpa Build
« Reply #9 on: January 27, 2023, 10:06:23 PM »
I did an old MTB conversion for my 2011 tour. Drop bars, lowest possible derailleur gears front and rear racks. Worked well on and off tarmac, except for muck on the drivetrain, mainly in bad weather.

I got a Thorn Raven Tour as replacement, after advice from Andy Blance at Thorn that I didn't need the heavier-duty Nomad for my intended use (cycle-camping in Western Europe with some use of tracks and paths).

He was right. The Raven Tour has been OK with large rear panniers, medium front panniers and, when necessary, more stuff strapped on the rear rack.

The Rohloff gearing, Chainglider, Thorn brand tubular steel front and rear racks were all improvements on my conversion.

The Nomad would have been a better choice if I had intended doing mainly off-road rides, the maximum tyre size on the Raven Tour is about 55 mm with mudguards.

AFAIK Sherpa is the derailleur equivalent of the Raven Tour. More recent Raven frames are slightly lighter duty than Raven Tour.

mickeg

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Re: Thorn Sherpa Build
« Reply #10 on: January 28, 2023, 01:14:17 AM »
.... Even so, some of the current Nomad builds are rated to be 40kg+ and that's without bar bag and water bottles!

I had not looked that close at the Nomad Mk III.  I assumed it had the weight capacity of a Mk II.

The attached file is a table from the Thorn Nomad Mk II brochure, Issue 20, Autumn 2012.  Based on the table, my size 590M Mk II has a capacity of 62kg when front panniers and three bottle cages are used.

Thus, the Sherpa carries a lot and a Nomad Mk II carries twice as much as a lot.  I agree with Dan, the Nomad can carry more than a Sherpa.

I am sure I had less than 60kg on my Nomad Mk II when the attached photo was taken, but I am quite sure it was over 35kg that the Sherpa was rated at.  I had about two and a half weeks of food on the bike in the photo, and of course all my camping gear.  Food weight was probably close to one kg per day, so probably between 15 and 20kg of food alone, 3kg of water in the cages, etc.  The photo was from my Iceland trip, my tent was one that is quite good in wind, it weighs over 3 kg.

I previously mentioned that I have three touring bikes, my third one is a titanium bike.  I consider the titanium one to be my light touring bike, the Sherpa my medium, and the Nomad Mk II to be my heavy touring bike.

in4

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Re: Thorn Sherpa Build
« Reply #11 on: January 28, 2023, 10:35:41 AM »
I can’t quite make out if you used those extending bottle cages er Topeak? I’ve stayed with those that came with my Nomad and use stainless steel bottles with them, bit  like these:  https://www.deporvillage.pt/bidao-de-bocal-largo-nalgene-500-ml-azul-tampa-preta?gclid=CjwKCAiArNOeBhAHEiwAze_nKKqFvBee3XKSbwqdFcFeDr_KkuxJSG4k5ISQq2fdb_Jt1PbotNGzmxoCaVMQAvD_BwE

I have a pair of those Ortlieb water sacks but was wondering whether to ditch them and the bottles in favour of carrying three ‘Fitzroy’ plastic bottles in those extending cages. Yes, the bottle are plastic but I reckon they’d be reusable for some time before any plastic ‘taste’ became an issue.

https://photos.app.goo.gl/PUePnFfbCN5wtcWv9
« Last Edit: January 28, 2023, 10:38:03 AM by in4 »

steve216c

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Re: Thorn Sherpa Build
« Reply #12 on: January 28, 2023, 01:23:42 PM »
If you want to upgrade the brakes but no go to discs then Magura hydraulic rim brakes might be right for you. When I rode my first v-brake bike I was amazed how much easier to maintain and how much better the brakes were than my old centre pulls. But when I bought my most recent bike with Magura rim brakes I was even more impressed about reliability, even braking power and improved braking control and distance. V-brakes are good. But Magura hydraulic rims are much better on so many levels. And they should fit on same fittings as V and centre pulls on frame and forks.

Of course, easiest is to find a bike ready to ride away on with your dream components. But factor in cost of upgrading with new parts may not be so economical as finding your dream bike already loaded with the components you’d prefer 2nd hand might be cheaper than buying cheap and upgrading.
If only my bike shed were bigger on the inside...

mickeg

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Re: Thorn Sherpa Build
« Reply #13 on: January 28, 2023, 02:27:18 PM »
I can’t quite make out if you used those extending bottle cages er Topeak? I’ve stayed with those that came with my Nomad ...

If you are commenting on the three big bottles on my Nomad in the photo, I am in USA and there are some brands of disposable water bottles that are 1 liter and fit perfectly in a conventional water bottle cage.  The photo I previously posted was Smartwater brand 1 liter bottles, I brought them empty from home to use because of their large volume.  (I use a velcro or elastic strap to hold the lower one in place due to the length of the bottle.)

Photo attached is from my Canada trip, that has one Smartwater brand bottle and two Life WTR brand bottles that I brought from home.  But when I got to Canada I found they sold both brands there, I did not need to bring them.  (But in Canada what I was used to seeing as Life WTR brand was Life Water brand.)  The Smartwater brand bottle is slightly taller than Life WTR.  These bottles do not come with a flip top lid, the lids I used are from other bottles.

And since these bottles are disposable, at the end of trips I put them in the recycle bin before getting on an airplane to fly home to make packing easier.  This link is an example.
https://www.target.com/p/lifewtr-premium-purified-water-1-l-bottle/-/A-51955216

The cages I used are the same size cages as all the other standard ones, but the cages I have were discontinued by Velocity over a decade ago.  They are adjustable for up and down position, they allow me to mount my cages slightly lower than the other brand cages which helps me fit that tall of a bottle in my seattube cage.

If you are wondering if any of the disposable water bottles sold in stores near you fit in a cage, take a piece of paper and wrap it around a bottle that you have that fits your cages well.  Then mark on that paper what the circumference of that bottle is.  Stick that paper in your pocket and your next trip to the store, use that to measure the circumference of bottles that you see.
 

lewis noble

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Re: Thorn Sherpa Build
« Reply #14 on: January 28, 2023, 04:12:23 PM »
Hello!

I rode a Sherpa for several years, and found it an excellent all-round bike.  Use included urban riding in heavy and congested traffic, the good posture and excellent v-brakes (Deores, as on the photo bike from the OP), made it ideal for that.  The brakes were pretty well as good as any I have ridden, including discs, except perhaps in the wet - Koolstop Salmon pads helped there.  I used it as well on a long 'B&B' tour through France, comfortable and 100% reliable.  About 15 - 16kg load then, sometimes much more on short trips to supermarket. 

Fitting disc brakes would probably require new disc-compatible forks as well as new hubs?  And I found the v-brakes on my Sherpa fine 99% of the time.  The only time I had any worry about them was a descent from Beallach na Ba in Western Scotland, in heavy rain.  And changing to a Rohloff would require quite a bit of alteration as well?  Others here would be able to advise better than me on that.

The Sherpa has now gone to my daughter, who has ridden it on a mixture of surfaces, no problems.  I bought an Audax, as more and more of my riding became road-centred day rides.

Good luck with whatever you decide to do.

Lewis