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Not sure I understand all of that…..but the basic problem with the longer biplane fork for me was that it raised the bottom bracket height too much.  The alternative 40mm shorter Thorn fork I now use allows me to have the correct pedal - seat distance and still be able to get a foot safely down when stopping.  Essential on sloping ground and when carrying luggage.  I am sure both fork types are well strong enough for my riding speeds and style!
Forks are measured crown race to axle (C>A) that's the only length that effects geometry, it makes no difference how much of that is crown and how much blade.  I think there must have been some misunderstanding with your bike, I doubt Thorn has ever offered forks with a 40mm difference intended for the same frame.

My Raven Tour came with a biplane fork with L1 = 410mm but shorter unicrown forks with L1 = 370mm appear to have been an option - reference from Test of Raven Tour on SJS website.  ‘Our Tour came with twin plate 531 ST forks…….a shorter 531 fork is also an option’
The RST used the shorter unicrown fork (for sharper handling?) and Thorn were happy to sell me the shorter fork when I cycled into them and explained the problem of high BB.
Did the RST have the same frame geometry as the Tour?   I know it used lighter tubes in places.
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Transmission / Re: Replace chain
« Last post by mickeg on Today at 02:24:44 PM »
On a loaded Nomad ( 45 x19 ) I did 46.6km downhill on Ardnamurchan in May. Still love the adrenaline rush and utter folly 😂

I only do the fast downhills on my derailleur bikes, not my Rohloff bike.  Ratio of chainring to sprocket in top gear on my road bike is 50/12.  My two derailleur touring bikes is 46/11, and my rando bike is 52/11. 

But if I am going down a long hill, I let my cadence drop to a slower pace to relax and let gravity do the work. 

The only time I put effort into pedaling on a downhill is if I am going down into a valley and several seconds later I will be pedaling up a steep hill on the other side.  On those occasions I do that to help maintain momentum on the uphill.
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Transmission / Re: Replace chain
« Last post by in4 on Today at 11:44:44 AM »
On a loaded Nomad ( 45 x19 ) I did 46.6km downhill on Ardnamurchan in May. Still love the adrenaline rush and utter folly 😂
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Transmission / Re: Replace chain
« Last post by jul on August 15, 2026, 09:52:43 PM »
For information, 36x16  transmission,  aboie 33km/h you can no longer pedal, sometimes it’s frustrating

Depends on your pedaling cadence.

I generally pedal relatively fast at about 90 rpm (tours par minute). With a 36x16 combination that translates into 36 km/h, which is way above a sustainable speed for me on the level, unless I have an exceptionally strong tail wind.

If necessary I can increase pedal cadence for very short periods. With a 36x16 combination at 120 rpm in the highest gear that would be 48 km/h. In practice, that kind of speed is not really useful for me, except perhaps when I negotiate medium size roundabouts, where I feel safer if I am doing roughly the same speed as most of the motor vehicules. 

My current highest gearing on any of my bikes is 42x19 on my Rohloff equipped Raven Sport Tour. I use that bike mainly for day rides with little luggage. Top gear with 42x19 is slightly lower than with a 36x16, the maximum speed I managed recently when pedaling (downhill) was 53 km/h at 137 rpm, just to see if I could still do that at age 69. But normally I would just stop pedaling and coast down the hill.

Yep, i did a mistake, 36x16 transmission, you can ride max at 43 km/h..

At 47km/h you pedal as a salade drainer
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Non-Thorn Related / Re: Stem bolt size question
« Last post by mickeg on August 15, 2026, 03:32:12 PM »
Ian, a time-honored way to remove rounded socket screws is to pound in the next larger size Torx bit. The damaged screw usually twist out easily with this method.

Best, Dan.

I have never heard of that.  That is BRILLIANT.
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Non-Thorn Related / Re: Stem bolt size question
« Last post by mickeg on August 15, 2026, 03:30:48 PM »
Bolt thread size or wrench size?

Usually, but not always the stem bolts that tighten onto the steerer tube are a 5mm wrench size, thread size 6mm.  But there may be exceptions out there.

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Non-Thorn Related / Re: Stem bolt size question
« Last post by Danneaux on August 15, 2026, 03:29:31 PM »
Ian, a time-honored way to remove rounded socket screws is to pound in the next larger size Torx bit. The damaged screw usually twist out easily with this method.

Best, Dan.
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Non-Thorn Related / Re: Stem bolt size question
« Last post by UKTony on August 15, 2026, 03:05:34 PM »
The bolts on my Deda Zero stem are M5 by 16mm. AK is 4mm. I think the bolt heads, albeit tapered,  would be classed as socket head. Spare matching bolts for various Deda stems are available eg from Condor Cycles.
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Non-Thorn Related / Stem bolt size question
« Last post by in4 on August 15, 2026, 12:56:08 PM »
Anyone know what size bolt this is? It’s on my Deda stem and it’s  ’rounded off’ probably because I used the wrong size hex/allen key. I think it’s an M5. I’m not sure what the correct description is for the top of the bolt. Tapered crown perhaps?
TIA
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