Discs + wet weather + gravel riding: struggling to swallow the kool-aid

fukawitribe wrote:

I think a lot of the point is that speed isn’t really the be-all and end-all from the GCN videos –  and that article wasn’t written by them. The GCN video is remarkably even-handed and interesting, especially in the conclusions and discussion about what could be done more or better.

I didn’t watch the video, just read that summary. I’ll give the video a go later on when it’s convenient to use headphones (I much prefer reading articles than watching a video). But yeah, most people buying disc brakes aren’t concerned about a few seconds difference in performance.

Edit: watched the video with subtitles now. Looks like the difference is within experimental error.

fukawitribe wrote:

hawkinspeter wrote:

@BTBS – I just did a quick search on performance difference between rim and disc brakes and found GCN’s testing that concluded that rim brakes are indeed faster. (Summary here: https://www.honeybikes.com/blog/2018/3/25/disc-brake-vs-rim-brake-performance-on-road-bikes)

However, for me the most important difference between rims and discs is the wet weather performance.

That article has cropped up a couple of times now and is ummm – interesting. Aside from the acknowledged looseness in the tests, they’ve stitched together some of the timing from the GCN video, doubled it up, and concluded that the lighter (rim-braked) bike is faster uphill. Then, on the descents, they found that the heavier (disc-braked) bike was marginally slower downhill in the dry (0.5%) but significantly faster in the wet – enough to better the deficit from climbing – so they said the rim-brake bike had carbon rims and must have been about twice as bad downhill as one with aluminium rims. So they halved the advantage on the heavier bike and tad-dah – the lighter rim-braked bike wins !!! They did at least admit that there are other areas to consider rather than straight ‘speed’ and I think it’s possibly safe to say from the language in the article that it’s the answer they might have prefered … 🙂

It might be flawed, but I didn’t see any other direct comparisons of performance between brakes (I didn’t spend long looking though). I would have thought that GCN would be more interested in promoting disc brakes, so the bias surprises me.

The Shimano Dura Ace rim
The Shimano Dura Ace rim brakes fitted to my 20 year old steel bike on Mavic rims are perfectly good. The Shimano hydraulic discs on my modern carbon bike are simply better.

Easy to write lots of words supporting one technology over another. Constructing conspiracy theories around marketing or nit picking why something new isn’t perfect in every scenario, real or imagined. But until you have had a good chance to actually live with and try something different then you have only opinion not informed opinion.

My discs howl now and again but only when wet, and so can rim brakes under the same circumstances. Cleaning them occasionally goes a long way to keeping them quiet.

Simplifying frame design, lol

Simplifying frame design, lol, it was simple before, have you any idea how much more complex a disc brake frame is compared to a rim brake, you’ve seen all the extra add on bits that are needed so that you can fit discs right, all the additional ‘beefing up’ and huge changes in frame design?

The excuse about carbon clinchers melting was feeble, a small number of people, mainly people who have no business descending in the mountains at high speed on carbon clinchers, and that was back in the early days with poorer compounds, Corima carbons have been fantastic for over a decade amngst others. Maybe those wannabe’s should learn how to ride descents or simply not cane it when there’s no need to or just bring along alu rims if they aren’t that great on descents and are worried about their cheap carbn rims!

I’m a mini V user on my tourer/audax/winter racer, it’ll take up to 55mm tyres, easily 45s with guards, Specialized made in my opinion the ultimate do it all bike in the Sirrus Pro Ltd, full carbon, room for 40mm tyres plus rack and guard mounts, std 68mm BSC BB and V pegs. Currently running it with Avid 7s but have TRP mini Vs if I decide to convert to drops.

Most of the offerings for gravel/adventure are fat bloaters, even the high end full carbon jobs are heavier than my Sirrus, all are disc brake offerings so for me none are of interest. If Tom Pidcock can win a Worlds junior cyclocross on cantilevers then it’s good enough for the rest of us!

For a benefit to a very, very small number of people in a very small fraction of situations were a well set up disc brake will do better than a rim brake, it’s just not worth the extra cost/weight and numerous downsides that most disc brake users experience.

Find a local bike shop that

Find a local bike shop that has a Park Tool DT-5.2 Disc Brake Mount Facing Tool (or equivalent).

This fixed 99% of all my squealing issues. Getting the faces of the mounts perfectly flat is key. Very few bikes have this area addressed as they come out of the factory. Even a layer of paint will cause issues.

It’s not the increased power
It’s not the increased power or reliability of disc brakes over rim that has made manufacturers switch but the byproducts of simplified frame and wheel design.

Carbon clinchers are inherently an unsafe design due to rim failure caused by excessive heat build up from the brake track. Taking away that brake track allows rims to be less complicated, use less material, and decrease manufacturing tolerances which in turn means less warranty replacements and possible lawsuits? It’s just a safer and cheaper design. I dunno if wheel manufacturer reputation is worth more to them than the money lost from losing sales due to the lack of worn out rim wheel replacements.

It also makes it easier (cheaper?) to produce frames with bigger clearances that get rid of complications like chain and seat bridges, and reduce the fork crown. I’m sure there’s some element of getting the consumer to buy another bike but there are definitely sound reasons why you’re not being ripped off. The next thing will probably be overall disc brake bike packages that are as light as former rim brake models.

It’ll also be cheaper to produce only one model of frame, wheel & components which is why they’ll all but kill off rim brakes.

But yeah, they’re noisey.

Yeah, I’ve got a similar

Yeah, I’ve got a similar issue on my road (not-CX) bike. Mine’s Ultegra with metal pads and they’re so loud when they get wet. I assumed that it’s to do with my pads/discs being dirty as I don’t take special care of them when I’m using a bucket of car shampoo to wash my bike.

I get embarrassed if I’m needing to slow down behind pedestrians and it sounds like I’m using a horn, so I try to keep the discs dry with gentle braking as I’m riding on the roads.

I was considering changing to resin pads when I next replace the pads, but maybe that’s not worthwhile if you’ve got a similar problem with them.