Spa Audax crash damage – fork?

[Brucey]

I'd echo the comments above to a great extent. However I'd also note that how the bike behaves also depends on the wheel weight and what is good/tolerable also depends on what kind of riding you are doing. Thus low trail + lightweight wheels + bunch riding often equals a wheel that other folk won't be so happy to follow, even if the rider is happy with how the bike feels.

cheers

[amediasatex]

Aye, horses for courses and all that, but Brucey's point is very valid, for close bunch riding and chaingangs a higher trail bike is definitely more favourable, especially if it's what you're used to. My 'fast' bike is very traditional road race geometry and better suited when I'm out on a fast group ride.

[Samuel D]

I don’t intend to change the trail. One reason I like it the way it is may be that I use tyres of low rolling resistance. That gives less force to act on the lever of the trail.

Handling wise, I like the Spa Audax a lot except for riding no-hands. That seems slightly harder on my bicycle than on previous road bikes. Occasionally it sort of gets away and I have to lean exaggeratedly to get back on top of the steering. But I ride no-hands while photographing with a phone or putting a jacket on in a group, so it can’t be that bad.

I’ll experiment with trail one day for my own education, but not now. Now I need something safe and familiar.

Regarding Brucey’s last point, people have commented that I ride smoothly. I certainly try to and feel I succeed. That is, until I run into things at high speed.

I wonder how much of SJS’s Reynolds 853 fork’s weight is in the 380 mm steerer tube. They say it weighs 895 grams, which isn’t that much lighter than the cheaper steel forks mentioned above. But maybe the fork blades are significantly lighter. They’re certainly thinner than the Surly blades.

[PH]

Glad you're recovered enough to be considering getting back on the bike even though it won't be for a while.
There seems to be the assumption that if you don't want carbon you want something to take luggage, there's a couple of other options you might consider though neither are lightweight - The SOMA ES fork if you can source one, I imported a frameset from the US a few years ago and even with taxes it was a decent price, a very comfortable frame and the best brake clearance of any Audax fork I've had. There's also the fork used on the Hewitt Chiltern, these are branded under several names, but the manufacturer's name escapes me. There's also some straight blade options like the Condor Pioggia, though I doubt they'd suite your aesthetic.
I have the V brake version of the Thorn 853, it's very nice, but not as magical as the price might suggest. At the same time I bought it (A couple of years ago) a friend had a custom fork made by Longstaff's for less.
I had a minor collision with a car last week, i walked away with a couple of bruises and scraps, but the bike came off worse, an S shaped front wheel and a bulge on the downtube of the aluminium frame. The carbon fork between them looks fine, the chances are that it is, but it's not a chance I shall take. I've had a handlebar failure which was bad enough, the idea of a fork failure...
Good luck with your continued recovery

[pwa]

Yes, cosmetic damage is just battle scars to be worn with pride.

[amediasatex]

I wonder how much of SJS’s Reynolds 853 fork’s weight is in the 380 mm steerer tube. They say it weighs 895 grams, which isn’t that much lighter than the cheaper steel forks mentioned above. But maybe the fork blades are significantly lighter. They’re certainly thinner than the Surly blades.

I think the quoted weights are about 100-150g lighter with an uncut steerer, so once you've lopped off a fair chunk of the steerer I think you'd lose another couple of hundred grammes.

I have the V brake version of the Thorn 853, it's very nice, but not as magical as the price might suggest

I think the canti brake version is a somewhat beefier fork? It certainly uses a beefier crown even if the legs are the same.

Good shout on SOMA, I'd forgotten about them as they are such a pain to source in the UK, but they have quite a nice range of forks available and they do ship internationally if you can;t find a local vendor.

[pwa]

I doubt it is likely to be any use to you, but I have an unused Spa audax carbon fork that in a "senior citizen moment" some years ago I cut down too far. It has 226mm of steerer measured from where the carbon finishes. If you use long steerers it will be no use but if you happen to use shorter steerers than I do it is yours. I have had it for years without finding a use for it.

[PH]

I have the V brake version of the Thorn 853, it's very nice, but not as magical as the price might suggest

I think the canti brake version is a somewhat beefier fork? It certainly uses a beefier crown even if the legs are the same.

Yes a different fork, but not by much and not designed for luggage. Thorn claim the caliper version is 805g with a 300mm steerer and the canti version 850g with the same steerer and 5mm longer dropout to crown. I like mine, well made, stainless dropouts, pleasing aesthetically, very comfortable - just no more so than the forks on my Hewitt tourer (Though that has a 1" steerer, so not like for like)
We had a fork discussion on here some years ago and some folks older steel forks were a good bit lighter, though it wasn't clear if they were like for like comparisons.

[PH]

I wonder how much of SJS’s Reynolds 853 fork’s weight is in the 380 mm steerer tube. They say it weighs 895 grams, which isn’t that much lighter than the cheaper steel forks mentioned above. But maybe the fork blades are significantly lighter.

From the Thorn brochure - 853 fork steerer is 0.71g per mm. But that doesn't match the 895g with 380 and 805g with 300
I'm looking at the brochure which doesn't say the uncut weight. By comparison, their standard Audax fork is 1040g with 300 mm steerer and 1.04g per mm steerer.

EDIT - A bit of cross editing/posting with NetworkMan, apologies for repetition!

[NetworkMan]

If it were me I’d be tempted by either the thorn 853 or getting a builder to make me a pair, but that would be the most costly option and may not represent good value.

The plain-vanilla Thorn Audax fork is probably more like a touring fork than a lightweight Audax type one. According the Thorn mega brochure (page 28, spring 2019) the Audax one weighs 1040g and the touring bike one weighs 1055g so I'd imagine the blades are similar. That is almost the same weight as the fork on my Spa steel tourer. The Thorn 853 fork is much lighter at 805g. and working backwards I reckoned the blades must be about the same weight as my old 531c Dawes Audax fork. It's a bit garbled in the mega brochure since both the plain-vanilla and 853 forks are described as "competition weight" in that same brochure (table on page 29)!

A view on the Thorn 853 vs. the original Spa CF fork from IOW here:-
viewtopic.php?f=5&t=131947&p=1384886&hilit=thorn+853+fork#p1384886

[NetworkMan]

After reading the above posts......
My old 531c fork has a 1" steerer (and quill stem) so I subtracted out the weight of the steerer from both my fork and the Thorn 853 Audax one to get the weight of crown and blades. IIRC the result was within 5%.

[amediasatex]

I had 5 mins on my hands...

Thorn Audax Mk3 forks for 57mm brakes, unknown tubing with low-rider braze-ons AND two lower sets of braze ons, 1 1/8th a head steerer ~220mm long = 945g


Unknown brand road fork for 57mm brakes, 531 tubing, 1 inch threaded steerer ~150mm 754g


Singular Osprey road fork for 57mm brakes, 4130 cro-mo tubing with low-rider bosses, 1 inch a-head steerer ~180mm 855g


Condor road fork for 49mm brakes, columbus tubing, 1 inch a-head steerer ~180mm 693g


All weighed on kitchen scales on very thin carpet, 1kg test weight reads 998g so they're accurate enough for me

All my other forks are plugged into bikes at the moment so their actual weights can remain a mystery for now, the only other one I know an exact weight for is a Columbus Minimal full carbon 1 inch threadless fork which is 322g with a 180mm steerer.

[slowster]

According to page 18 of this list of available Reynolds tubes, there is only one set of 853 blades available for standard forks (the others are either for disc brakes, aero blades or are 29er unicrown).

That fork has 27.7mm x 20mm oval diameter, 1.0mm/0.6mm tube thickness and 15mm x 45mm rake. There are 631 blades with the same dimensions. The basic butted R blades with the same diameter and tube thickness are supplied straight to allow builders to bend the tube themselves to their required amount of rake.

As I understand it (please correct or enlighten me anyone if I've got this wrong):

- Forks built with any of those three blades should weigh the same, all other things being equal.
- They should all exhibit the same stiffness/flexibility*
- The benefit of the higher grade steels like 853 is the greater strength, which means it is more dent resistant and maybe will have a longer lifespan because the strength means it recovers from normal flexing in use better than a basic steel alloy, which may experience micro-yield fractures.

* However, this is completely at odds with statements by Dave Yates about 853 vs R blades. He maintains that 853 blades are significantly stiffer, too much so for most uses/riders, and I think he usually encourages most customers to have R blade forks, regardless of whether the frame is 853, 725 or 631 etc. He came to this conclusion when he was riding a lot of audax events, and finished a long (600km?) event in discomfort/pain which he put down to the overly stiff 853 forks. He then built a set of R blade forks to replace the 853 forks, and they confirmed his suspicion. I confess I do not understand how that can be the case, since I would have thought that the particular alloy should not make a difference if the tube thicknesses are all of the same dimensions, but I don't doubt Dave Yates' knowledge and skill both as a builder and also as a very experienced rider.

[amediasatex]

the listed dimensions may be the same but it's not specified if the butting profile is actually the same?

ie: two blades listed as 370mm x 1.0 - 0.6 could differ thusly:


(apologies for hastily drawn crude diagram!)

anyone know?

[PH]

According to page 18 of this list of available Reynolds tubes, there is only one set of 853 blades available for standard forks (the others are either for disc brakes, aero blades or are 29er unicrown).

Good list, but Thorn claim Reynolds make theirs exclusively for them. I have no reason to doubt them, some of the other tubes in my Thorn 853 frame are not listed either.