The bottom falling out of the rim-braked market?

[Cudzoziemiec]

I wandered into an LBS yesterday and only four or five road bikes had disc brakes, and they were all in the "gravel" mode. There were at least twice as many road bikes with rim brakes, and all the tourers had rim brakes. So I don't think rim brakes are being abandoned, just that discs are making their niche.

Have we mentioned mudguards in relation to brakes yet? The other day I had to stop (more than once) to dig clayey mud out of the (admittedly tight) gap between tyre and 'guards. The back wheel was jammed solid to the point it would not rotate, and by far the tightest clearance is under the brake bridge. If that bridge is freed from its role as a brake mounting point (and it clearly has no structural role, as many bikes with no mudguard capacity don't have it) then it's also free of the restrictions of brake caliper arm sizing, meaning it can be fitted higher and redesigned as purely a mudguard mounting point. In fact, one of the bikes I saw yesterday (I think it was the Focus Mares) had done precisely this, at least with the lower mounting point by the bottom bracket. This is going to be especially beneficial with bikes that get ridden off road, of course, which is also where AIUI disc brakes are most advantageous. My bike isn't a "gravel" bike or anything of that sort, I just like riding on bridleways from time to time. Disc brakes and wider mudguard clearances would be useful at those times; of course there's a balance to be struck between road and off-road usability but it's a fuzzy zone rather than a hard point.

would these help?
https://www.compasscycle.com/shop/components/fenders/tire-wipers/

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I've heard of such things but never seen them. I can't imagine how precisely they must have to fit in order to remove flints etc but not drag on the tyres. I'm not at all surprised that Jan Heine is selling them though.

[mrcharly-YHT]

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I've heard of such things but never seen them. I can't imagine how precisely they must have to fit in order to remove flints etc but not drag on the tyres. I'm not at all surprised that Jan Heine is selling them though.

They press lightly on the tyre. They only work with very smooth tyres and are polished steel so don't drag. Used to be very popular with fast club riders back when that meant riding on smooth tubulars and really not wanting punctures.

[julk]

would these help?
https://www.compasscycle.com/shop/components/fenders/tire-wipers/

! ! !
I've heard of such things but never seen them. I can't imagine how precisely they must have to fit in order to remove flints etc but not drag on the tyres. I'm not at all surprised that Jan Heine is selling them though.

Wow they were hot stuff in the 1960s, I used them then, thank god for puncture resistant tyres now...

[Samuel D]

I can't imagine how precisely they must have to fit in order to remove flints etc but not drag on the tyres.

Great precision isn’t needed, because the friction is so low that it can be largely ignored (much like dragging pads on disc brakes). If you doubt this, imagine trying to brake a bicycle by dragging a paper clip on the tyre.

[Cudzoziemiec]

I'm not thinking of drag so much as gradual abrasion to the tyres. Might have been a sensible precaution back in the '60s, but now I'll stick with modern tyres TYVM!

[frankly frankie]

I had to stop (more than once) to dig clayey mud out of the (admittedly tight) gap between tyre and 'guards. The back wheel was jammed solid to the point it would not rotate, and by far the tightest clearance is under the brake bridge.

The trick (on a road bike) is to make sure there is some other point of even closer clearance, upstream of the brake bridge.  Most simply, the back edge of the mudguard.  (NB this doesn't work too well if you also use mudflaps!)  If you set this back edge clearance to, well, 1mm or less - it has much the same effect as the tyre saver devices described above.  There will be no build up in the brake bridge area and most solid material will just get wiped off and not get under the mudguard at all.

It's extremely bad to have the brake bridge, or aywhere near the top of the mudguard, as the point of least clearance, because the detritus that collects there just falls off into the chain and wrecks the transmission.

[hubner]

Off-topic...flint catchers/tyre savers have been around a long time.

http://www.classiclightweights.co.uk/components/flint-catchers-comp.html

Maybe useful if you ride on tyres with paper thin casings and tread. But what about the noise, and what about riding in bad conditions, the tyre will be covered in muck, imagine placing a wire across that tyre...

Back on topic:  pros will eventually ride disc brakes whether they like it or, there's just too much commercial pressure. Of course once all pro bikes are disc braked, it won't make any difference because there's no advantage if all riders in a race have disc brakes.

Road bikes with  disc brakes will steadily become more common, gradually they'll become the norm. Bikes with rim brakes will still be available, just not common, just like quill stems, frames with horizontal top tubes etc.

[LittleWheelsandBig]

There is no noise from flint catchers.

[vorsprung]

I have used bikes with road tyres and drops and disks for commuting.  That's BB7 disks

They are better in the wet than rim brakes.  They are better because when approaching a place I want to stop or slow up such as a junction or corner the rim brakes need an initial pull "on" to remove water.  The disks do not.  The wet weather actual full stopping power of disks is, IMHO also a tiny bit better

I have recently obtained a carbon "adventure" bike with drops and hydraulic disks.   It is light as I would expect a nice CF bike to be.  I do not feel that the extra weight ( mine has the lighter mounts that Zinn claims are rarely used ) will be significant on longer rides.  To me the bike is light.   If I want to save weight I'll go on a diet

If I am in the middle of a longer ride and it starts raining, I am just fine if on a disk bike or a rim brake bike. 

But there is no doubt that in UK conditions for people that ride long distance disks are a "nice to have".  If you care about less than a kilo of extra weight then maybe you have different expectations to me.  When I do the sums for weight saving under audax conditions I conclude a kilo or two either way is no difference compared to other factors.

See for instance https://audaxing.wordpress.com/2010/06/30/stressing-over-the-mille-cymru/

[DrMekon]

I agree. Much as the money I've put in to my light bike makes me want to use it on events, the reassurance that I'll be able to stop no matter how cold or tired my hands are makes me want toi take the bog standard disc bike. Sadly, my bikes aren't equal in all other respects, so the gap is 2kg+. However, the ways I've saved weight (asssaver instead of guards; very light, stiff wheels; very light, stiff carbon bars; very light, stiff carbon post; very light, barely padded saddle) on my quick bike have made it feel a much riskier prospect on 200km+ events. In contrast, getting on the admittedly still light disc bike is like popping on comfy slippers.

I think a Domane SLR could be built sub 7.5kg and still be comfy, but I think you'd be looking north of £5k - the Ultegra equipped 6 is £4K. You'd need Red22, some Aeolus 3 wheels, maybe some Ritchey WCS bits.

http://www.trekbikes.com/us/en_US/bikes/road-bikes/endurance-race-bikes/domane/domane-slr-6-disc/p/1477300-2017

It would look lush (and can take 35mm tyres and guards if so minded). BTW, anyone interested in the Isocore bar, I hear it's so comfy, but the very square shape and soft feel makes in "unsuitable for sprinting" < sounds great to me. Mate who's done the TransCon has tied it and says it really filters ("deadens" road noise).