I recently acquired a Thorn Raven Enduro MTB frame, size 589L.

I am now looking for a suitable rigid fork for an all-year city commuter build.

Any good suggestions? Carbon or steel?

Also, would it be possible to fit 27.5" wheels on the frame?

Best wishes and happy trails
Mikkel from Denmark

Quote from: in4 on June 08, 2026, 10:09:16 AM

Perhaps it’s simply a case of business realities.

Probably

Oh, I think we can take that as a 99% certainty. Here are just a few costs associated with such an efflorescence of models and fits as offered by Thorne while Andy Blance was their designer, all of which I knew about before I went to business school:

Cost of capital (interest, repayments of loans cutting into distributable profits) to finance so large a range, warehousing space built or rented, sales lost because a large range of sizes and fits and models must be compensated by reduced colour range which is arguably more important to the vast majority of bicycle purchasers, time to train customer-facing staff in so large and varied a range, multiplication of showroom fit-out of so many models meaning larger stocks of expensive parts. The absolutely brilliant 100 days free trial also brought costs to the vendor, as well as welcome buzz on the internet. We also saw some of the fits at the margins being offered well after the main body of the production was sold, often at bargain prices; these discounts are an additional cost of so large a range.

On the other hand, you might say that the two main ranges established Thorn with a bang as a premier manufacturer of touring bikes after making custom bikes ran into a brick wall of costs and Far Eastern competition, and very likely brazier staffing problems too. (A quarter century ago already, when I drew a design for a custom bike built of triangulated small tubes, I couldn't find anyone except art school welders and silversmiths-- Jesus help me! -- to braze it together for me.) Thorn wouldn't be THORN today without all that; it might not be more than a fringe curiosity, as so many of the once famous custom builders in Great Britain have become. Whichever way you choose to do it, it is expensive to establish a mainstream brand, and niche brands perversely cost more to establish.

There is a time to take such a risk, and pay its costs, and inevitably a time arrives for consolidation and rationalization.

***
It's worth saying that this is a standard business school (or at least good, meaning non-political, business school) applied micro-economics analysis: in short, a point well understood would arrive where the owner of the business would have to make some unavoidable hard choices. 

Personally, I came to appreciate Thorn's exquisite care for the fit of their riders after Sheldon Brown drew my attention to it, and to Mr Blance's insistence on the best value, long-lasting component choices which would least often immobilize the tourist in some godawful place.* Getting on for twenty years later I see no reason to change my mind about either early impression.

*In Oz you get a choice between 'The Pub With No Beer' and 'The Fatal Wedding', the latter 114 stanzas that start, 'The Hearse Overturned At The Crossroads.' You shoulda stayed in Melbourne: at least there you can get a 'Floater' from the cart at the bottom of Spring Street, which is a meat pie in a bowl allegedly of pea soup, and the only danger is the tram lines bending your rims as it they cast you onto the tarmac.

Perhaps it’s simply a case of business realities.

Probably

Going from imron back to powercoat doesn't seem like such a step down in an era, when frame-protection tape is so common in the bicycle world. Primarily favored by bikepackers to avoid bag-rub, but it’s not as if there are any downsides to using it even if one doesn’t have such bags.

My Nomad Mk2 frame is powercoated and even unprotected by tape, and used now as a local-use bike in a wet climate. I can't say the paint seems particularly more vulnerable than my imron Nomad Mk3 frame.

Frame tape is fine in the obvious areas but it won't wrap around bottle bosses, cable guides, and rack mounts, which in my experience with my Thorn bikes are areas which start to rust and from where it creeps under the paint and can start to bubble.
Maybe the Thorn paintwork has improved since I bought mine. But I liked the idea of the more durable Imron paint and stainless steel fittings.

Perhaps it’s simply a case of business realities.

Another contribution from someone with no experience of the Mercury 40, no obligation to read...

it appears the Mercury 40 is a Mercury Mk3 with a less durable finish, Thorn's own-brand high-spec tubing and a gate in the rear triangle. There is every chance it will be all but indistinguishable from a Mk3 to ride, and so some reflections from people who've owned Mk3s for a few years seemed more than tangentially relevant.

I'd be interested to ride and know, I'm not sure the tubing has the same degree of manipulation, the stays are likely to be stiffer to accommodate the belt and gate.  OTOH I have speculated in the past that the the design may have been a bit self indulgent. I am somewhat sceptical that a single frame can replace the Mercury, Club Tour and Audax models without there being some compromise. Only by riding would one know if that were correct and where such compromise might have been made.
The powdercoat on my Raven was adequate but not brilliant, the DuPont enamel on my Mercury is a superior finish to that.  But powdercoat has moved on in twenty years, I've seen some fantastic finishes in the last few years, including a multi coulered Tout Terrain,  so I'm not assuming it is inferior.  I also note the fork is only available in black, like it was on the original Raven, I can't see that being popular.
The Mercury 40 frame is £100 cheaper than the last batch of Mercurys, I wonder what the price of the next batch would have been.  We can be pretty sure not the same, the price jump on the Nomad between batches was over £200. I was thinking Thorn's pricing was getting close to a custom frame, but I had a look at my local frame builders pricelist and that isn't the case.  Their prices are up 50% since I last looked, though they went bankrupt and were bought out by new owners in that time.