Spa Cycles' Disc Braked Tourer and Audax

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fastpedaller
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Re: Spa Cycles' Disc Braked Tourer and Audax

Postby fastpedaller » 13 Sep 2018, 3:28pm

PH wrote:Worse IMO would be to use the canti mounts and have the ugliness of the unused disk mounts. Not a deal breaker even for me, I have a frame with both :oops:

Could fit 2 sets of brake levers and 2 sets of brakes (if you have rim-brake friendly rims) and have the ultimate braking system for long alpine descents :D

NetworkMan
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Re: Spa Cycles' Disc Braked Tourer and Audax

Postby NetworkMan » 13 Sep 2018, 4:05pm

Seeing the fork makes me wonder. Is the ride harsher than on the rim braked tourer because of the stiffer fork? Does the ovalised down tube offset this for it not to matter? Is all this hidden by the squidgy tyres that most people will fit anyway?

bgnukem
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Re: Spa Cycles' Disc Braked Tourer and Audax

Postby bgnukem » 13 Sep 2018, 5:47pm

Also interested in how harsh the ride is compared to a rim-braked bike. I recently fitted Surly disc forks to my 26"-wheeled commuter after getting fed up of wearing out today's chocolate rims, but the stiffer fork made for a very unyielding ride quality noticeably harsher than before (and the previous steel fork was no lightweight, being built by Mercian with a solid crown).

Is there any way to design a disc-braked frameset to give ride comfort (particularly at the fork end) while maintaining enough stiffness to cope with the braking torques?

Does using a 1" steerer make any difference in this respect as my most comfortable bike is my old Dawes with a 1" steerer, 531ST forks and it's possible to see noticeable fore-aft movement of the front wheel axle over rougher road surfaces which I don't see on my other bikes (using steel or carbon forks with 1 1/8" steerers).

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honesty
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Re: Spa Cycles' Disc Braked Tourer and Audax

Postby honesty » 13 Sep 2018, 6:38pm

fastpedaller wrote:
PH wrote:Worse IMO would be to use the canti mounts and have the ugliness of the unused disk mounts. Not a deal breaker even for me, I have a frame with both :oops:

Could fit 2 sets of brake levers and 2 sets of brakes (if you have rim-brake friendly rims) and have the ultimate braking system for long alpine descents :D


CSS rims and some cantis would make a decent set of drag brakes ;)

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horizon
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Re: Spa Cycles' Disc Braked Tourer and Audax

Postby horizon » 13 Sep 2018, 8:49pm

NetworkMan wrote:Seeing the fork makes me wonder. Is the ride harsher than on the rim braked tourer because of the stiffer fork? Does the ovalised down tube offset this for it not to matter? Is all this hidden by the squidgy tyres that most people will fit anyway?


You are risking a huge thread diversion (despite the thread title!) because this is at the heart of the matter. There is a huge thread somewhere on this very topic (I just hope Brucey doesn't read your post :D :shock: ).

One must assume that Colin has made the right choices and compromises: if you want discs (which I personally don't object to) then you take the rough with the smooth, so to speak.
Bikes belong on trains: two spaces per carriage would meet most needs.

NetworkMan
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Re: Spa Cycles' Disc Braked Tourer and Audax

Postby NetworkMan » 13 Sep 2018, 9:05pm

horizon wrote:
NetworkMan wrote:Seeing the fork makes me wonder. Is the ride harsher than on the rim braked tourer because of the stiffer fork? Does the ovalised down tube offset this for it not to matter? Is all this hidden by the squidgy tyres that most people will fit anyway?


You are risking a huge thread diversion (despite the thread title!) because this is at the heart of the matter. There is a huge thread somewhere on this very topic (I just hope Brucey doesn't read your post :D :shock: ).


Oh cor blimey guv :oops: :shock: . I found another thread an hour or two back, though it's quite a short one - lets point people in that direction :)
viewtopic.php?f=5&t=124817

Smith873
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Re: Spa Cycles' Disc Braked Tourer and Audax

Postby Smith873 » 13 Sep 2018, 10:28pm

What is the weight difference between the Aubisque and the equivalent steel Spa Audax? I'm guessing there will be a weight penalty for the disc brakes, but how much. I've e-mailed Spa to ask but no response yet.

I've been audaxing on my steel Spa Audax for 3 years now and I love riding it long distances. Although as it's the 50cm frame I had to have it fitted with the steel fork because of the offset. So it's quite a lump. I'd really like a carbon fork to reduce weight, which sounds like it might soon be a possibility according to Colin's earlier post.

NetworkMan
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Re: Spa Cycles' Disc Braked Tourer and Audax

Postby NetworkMan » 14 Sep 2018, 11:46am

Smith873 wrote:What is the weight difference between the Aubisque and the equivalent steel Spa Audax? I'm guessing there will be a weight penalty for the disc brakes, but how much. I've e-mailed Spa to ask but no response yet.

I've been audaxing on my steel Spa Audax for 3 years now and I love riding it long distances. Although as it's the 50cm frame I had to have it fitted with the steel fork because of the offset. So it's quite a lump. I'd really like a carbon fork to reduce weight, which sounds like it might soon be a possibility according to Colin's earlier post.

Colin wrote upthread:
But before that I will have in my hands prototype Audax 2 bikes, with rim brakes and carbon forks with alloy steerer (as now) except that we can now get forks with different offsets, so again the small bikes will have different fork offset and head angle to the big bikes, and the frame tubes will be ovalized.

So if you wait for the Audax 2 you might get what you want. You might even be able to fit one of the new carbon forks to your bike if the offset suits and the steerer is 1.125" non-tapered.
Are you sure you'd notice the ~500g. weight saving on the fork? I've just saved ~1kg on my tourer but apart from the wheels I'm not at all sure I can notice the difference. If I lift it up by hand I can but riding I have my 60 kg weight and the 1 kg. is only 1.4% of the total. 500 g. on a 10 kg bike would only be 0.7% of the total.

Whippet
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Re: Spa Cycles' Disc Braked Tourer and Audax

Postby Whippet » 14 Sep 2018, 9:47pm

531colin wrote:
PH wrote:.........There's now a lot of models from Spa. At some point does it become too many? Their business not mine of course, though there's plenty of business studies that show increasing choice doesn't necessarily increase sales...…….
I watch with interest, though it's unlikely I'll buy another bike, though if they ever offered the Elan with Rohloff fittings I might be tempted to give it a try.

Not my decision either, but I think we are due for a prune of some bikes. (if a customer can't decide, they go away)
I would like to see Wayfarer replace Roughstuff and Tourers …..although I confess a sentimental attachment to the Ti tourer I don't know how many sell. I could improve the design now, but you are still stuck with STIs, peoples aversion to canti brakes, and the limited clearance of mini-vees....so a light tourer with rim brakes maxing out at 35mm tyres? As previously, theres a whole lot of new Audax prototypes on their way, which will be better than the originals, but again I don't know the market....it all seems to be going disc brakes and big tyres.
I can't see Rohloff being on the horizon, but I know where I would look for cable routes.


I've got a 2012 Ti Tourer that I'm still very fond of. As you allude to, the compromise is with the brakes, I found the minimal clearance of the mini V's too annoying so have swapped them for ( very ) long reach dual pivot brakes which are OK ish but obviously still a compromise. 32mm tyres are fine by me, don't think I need any bigger. I'm also not that tempted by disks.

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531colin
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Re: Spa Cycles' Disc Braked Tourer and Audax

Postby 531colin » 16 Sep 2018, 7:58pm

Now, I don't have records of what cycle parts were fitted in 2012, and I rather doubt that anybody else does either.
However, this photo is dated 2012 (by the camera, not me!)...https://www.flickr.com/photos/52358536@N06/7262928344/in/album-72157624571269648/. The brakes are branded "Genetic", and I think there may have been others too, before we settled on Tektro RX 6 mini-vees., like this...https://www.flickr.com/photos/52358536@N06/15234665408/in/album-72157624571269648/
The Tektro RX 6 are a very good brake; because the arms are rigid you don't get any "lost motion" by the brake arms flexing, every millimetre the cable moves has an effect on the braking. With bendy brakes, you can apply the brakes then pull the lever all the way back to the bars just flexing the brake arms. So with RX6 you can have decent pad clearance and good braking, much better than long dual pivots.

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531colin
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Re: Spa Cycles' Disc Braked Tourer and Audax

Postby 531colin » 16 Sep 2018, 8:17pm

Smith873 wrote:What is the weight difference between the Aubisque and the equivalent steel Spa Audax? I'm guessing there will be a weight penalty for the disc brakes, but how much. I've e-mailed Spa to ask but no response yet.

I've been audaxing on my steel Spa Audax for 3 years now and I love riding it long distances. Although as it's the 50cm frame I had to have it fitted with the steel fork because of the offset. So it's quite a lump. I'd really like a carbon fork to reduce weight, which sounds like it might soon be a possibility according to Colin's earlier post.


There is a small weight penalty with disc brakes. A bit on the forks, just a tiny bit on the frame; and "some" on the brake calipers and wheels; exactly how much that is depends on whether or not you choose really light wheels for rim brakes, or something more everyday.
But the biggest difference is going to be between steel or carbon forks; as Network Man says, you can use the "new" longer-offset carbon forks on the "old" smallest Audax, the dimensions are within a few millimeters. (2mm offset, 4mm length.)

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531colin
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Re: Spa Cycles' Disc Braked Tourer and Audax

Postby 531colin » 16 Sep 2018, 8:27pm

bgnukem wrote:Also interested in how harsh the ride is compared to a rim-braked bike. I recently fitted Surly disc forks to my 26"-wheeled commuter after getting fed up of wearing out today's chocolate rims, but the stiffer fork made for a very unyielding ride quality noticeably harsher than before (and the previous steel fork was no lightweight, being built by Mercian with a solid crown).

Is there any way to design a disc-braked frameset to give ride comfort (particularly at the fork end) while maintaining enough stiffness to cope with the braking torques?

Suspension fork will do that.
bgnukem wrote:Does using a 1" steerer make any difference in this respect as my most comfortable bike is my old Dawes with a 1" steerer, 531ST forks and it's possible to see noticeable fore-aft movement of the front wheel axle over rougher road surfaces which I don't see on my other bikes (using steel or carbon forks with 1 1/8" steerers).

1" steerer is noticeably more flexible than inch and eighth. But then a frame with inch top tube and inch and eighth down tube is noticeably more flexible than a frame with oversized tubing.
Some of those old UK made Dawes 531 frames were dreadfully floppy. As they all used the same tubes and lugsets, the differences can only be due to how accurately the tubes were mitred, and how well the joints were filled with spelter.

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531colin
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Re: Spa Cycles' Disc Braked Tourer and Audax

Postby 531colin » 16 Sep 2018, 8:32pm

NetworkMan wrote:Seeing the fork makes me wonder. Is the ride harsher than on the rim braked tourer because of the stiffer fork?

Yes
NetworkMan wrote:Does the ovalised down tube offset this for it not to matter?

Down tube is only ovalized at the BB end, so basically, no. Top tube is ovalized at the front (against shimmy) but I doubt it makes the frame much more forgiving.
NetworkMan wrote: Is all this hidden by the squidgy tyres that most people will fit anyway?

largely, yes

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531colin
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Re: Spa Cycles' Disc Braked Tourer and Audax

Postby 531colin » 16 Sep 2018, 8:38pm

horizon wrote:…………….. Are there any structural downsides to too long an exposed steerer tube? Does the head tube provide strength to the steerer? Or is this a baseless concern? I have long exposed steering due to stem raisers but although AIUI that isn't a problem (steel steerer, but alu extensions), the higher headtube gives some reassurance. Aesthetically I prefer a longer head tube but that on the tourer is totally fine visually AFAIAC.

With inch and eighth steel steerer, I think you would have to do something fairly dramatic in order to break anything....like putting a nice stress-raising score in the exact bit of the steerer which is stressed, then heaving on big wide bars for a good while.