Why I’m swapping back from disc brakes to rim brakes
Updated: Jun 15, 2020
Edit June 2021: I might have changed my mind, again. Check out my review of the 2021 Giant TCR on my new website.
If you’ve been following my musings and reviews on the blog, you’ll know that I took delivery of a Giant TCR Advanced Pro 0 Disc earlier this year. You’ll also know that, after 1,000km and two trips to Mallorca, I was left unsure as to whether or not it was the right bike for me.
And so a couple of weeks ago I made the very difficult decision that it probably wasn’t the right bike for what I wanted and that it was time to cut my losses and part-exchange it for a different model.
Before I go on, I want to make one thing really clear. I think the Giant TCR Advanced Pro 0 Disc is a very good bike. No ifs or buts, it is a great bike. I extolled its many virtues when I wrote the initial review here.
If I had to choose just one bike for year-round riding, come rain or shine, flat roads or hills, this is the kind of bike that I would choose. A super-responsive frame, high specification components and the superb latest-generation Ultegra Di2 and hydraulic disc brakes.
As was amply demonstrated flying downhill on super-slippery Mallorcan roads, this is the bike you can trust to deliver in all conditions.
However, after a few months of ownership (bear in mind that the bike shares shed space with a Giant Trinity, a lesser-specced Giant TCR disc with mechanical 105 and hydraulic discs, a Propel Advanced Pro 0 and two TCXs) it became clear to me, that while it is a superb all-rounder, it doesn't really excel in one single area.
That’s not actually quite true; the bike is excellent downhill, where the geometry and hydraulic discs really shine (although I wonder whether the disc-equipped Propel is even faster). But in terms of outright speed on the flat, the Propel is faster. And in terms of climbing, the Propel is also arguably faster (being a non-disc 2016 version it’s nearly 400g lighter than the TCR disc). In the wet, well I have the lesser-specced TCR for that, preferring to keep my ‘summer bikes’ for fair weather (to be fair, the TCR Advanced Pro 0 Disc is actually ‘better’ in the wet, I just wouldn’t want to get it mucky!).
And so, I found myself questioning my decision to go for a disc-equipped summer bike.
Why? Well for the following key reasons:
1. Hydraulic discs no doubt work better in the wet and down long twisty mountain descents. BUT I already have a disc-equipped bike for wet rides and, for 11 months of the year, I don’t have any nice long mountain roads to descend. In the dry and on the sorts of roads I ride, rim brakes work just fine. 2. You really do notice the weight penalty of the hydraulic brakes. I would guess that the weight penalty for discs is at least 400g on most road bikes. If, like me, you weigh sub 70kgs, that can make a noticeable difference to your climbing ability (a heavier and more powerful rider probably won’t notice the extra weight so much). 3. The extra cost of the discs can be invested elsewhere, funding a lighter frame or components, adding to potential weight and performance benefits. 4. You don’t need disc brakes to run wider tyres anymore. The new Ultegra rim brake calipers have been redesigned to accommodate wider tyres (up to 28mm I believe). I still run 25mms. I guess if you’re a bigger rider and want to run 30mm tyres you would still opt for disc brakes.
You may not entirely agree with the reasons above, but they were my reasons for deciding to ditch the disc brakes on the summer bike and go back to 'old school' rim brakes.
What did I choose to replace the Giant TCR Advanced Pro 0 Disc? Well, of course, naturally I chose another Giant. And indeed another TCR. But this time I’ve opted for the lightweight Giant TCR Advanced SL 1.
It has the lightweight SL frame and forks. It has mostly Giant’s proprietary SLR components (the lightest weight components they offer) and it comes with the new Shimano Ultegra R8000 Ultegra Di2 groupset (rim brakes, obviously). Fully-built with deeper 55mm SLR0 wheels and Garmin Vector pedals, the bike comes in at a respectable (if not ultra-light) 7.1kg (Garmin’s stated weight of the Vector 2 power pedals is 434g, so that makes the bike weigh more like 6.7kg without pedals).
That’s at least 1kg lighter than the TCR Advanced Pro 0 Disc (which came in at 7.9kg without pedals). Hopefully that will make a noticeable difference when climbing.
As for the flats, the SLR0 55mm wheels should be a touch more aero (albeit maybe 50g heavier) than the standard 32mm ‘climbing’ wheels that normally come with the bike (these are always on standby in the shed if weight is more important than speed on any particular day).
So far, I’ve only had two very short rides on the TCR Advanced SL1, so it’s too early to even really give first impressions (an unexpected work trip to Australia and New Zealand came at just the wrong time!). But of course I’ll be updating the blog in the coming weeks and months.