Disc Brakes on a Tri Bike

I’m looking into an entry level tri bike. 105 components.
Looking at 2 bikes and the only significant difference is disc brakes–about $900 more for the disc brakes.
I’m thinking the disc brakes may allow a tire that is more comfortable for long events.
Wondering if anyone has any pros/cons for each type of brake.
Happy training!

Get with the program. Get hydraulic brakes. They are superior in pretty much every way. My TT bike has rim brakes and it basically has zero braking in wet conditions and marginal braking in dry conditions. Not true with hydros. If you want to ride that bike for training and racing (which I do) then you’d be much better off with hydraulic brakes in my opinion. I’m an old guy, too, who raced for over four decades on rim brakes. Lots of old guys cling to rim brakes because they are stuck in the past. I’ve done both and here’s the key–I’m a really fast descender who lives where there’s descents. Hydro’s are far superior if (like everything mechanical) you keep them tuned and maintained. If you’re just doing flat, easy TTs, then take whatever is the best deal–but still make sure your brakes are tuned and maintained. ALWAYS RESPECT THE N=1 RULE–everyone is different.

Disc brakes can allow for a bike to be designed with more tire clearance, but with TT/Tri bikes, the design engineers probably aren’t taking full advantage of that aspect of the technology. There probably isn’t going to be clearance for more than a 28mm tire. However, the improved comfort of a 28mm tire isn’t to be overlooked. I can barely barely fit a 28mm Schalbe Pro 1 on narrow rims in my rim brake Trek Speed Concept. I’m guessing that most disc brake tri bikes would fit 28s more comfortably and on wider modern rims. On my road bike, I run 28mm GP5000TLs on 21mm internal width rims and that setup is :ok_hand:

There’s also the improved braking to consider. I know that a lot of people argue that you shouldn’t need to worry about braking too much when you’re racing on a tri bike, but most of people train on these bikes as well as race. And regardless of whether you’ll be putting in long training days on open roads or not, disc brakes just feel better and make riding a bike more fun.

If nothing else, disc brakes will give you confidence in your future compatibility with wheels. We’ve already been seeing most big brands’ flagship road bikes being released a disc brake only and wheels won’t be far behind. The new Zipp 303 is disc brake only, the new Roval Rapide is disc brake only. I suspect that deep wheels and rear discs will be a few years behind, but I think in 4 or 5 years you’ll be hard pressed to find a set of new rim brake wheels of any depth from a major brand.

Out of curiosity, which bike are you looking at?


Speed phreak vs quintana roo PRfour

15, 20 years after mountain bikes, the road bike market is transitioning to disc brakes as well. IMHO it is a worthwhile investment, not only is braking much better (it is easier to generate significant braking force and to modulate braking, plus, you have significantly better braking in wet conditions), but since the whole industry is moving to disc brakes, your bikes will be more future proof.


Agree with OreoCookie - Biggest reason I would go with Disk brakes on a new tri bike purchase today is the future proof and resale

Where the industry is going
Better braking in wet weather
Carbon race wheels seems to be more affordable and longer lasting
Generally more tire clearance

If you travel with the bike and have to pack it away- bleeding brakes isn’t fun
Brake squeal and rotor rub - if you know you know - and how you have to baby the rotors (getting bent, greasy/oil, or worn)
hydro levers have gotten smaller but are still bulkier and clunkier than their rim counterparts

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I just put together a rim brake TT bike (Look796)

I advise you to go disk brake if you can swing it. The reason is that wheels are getting wider and rim brakes especially built in or direct mount ones don’t accommodate wide rims. The other reason is that you can run carbon wheels and not worry about destroying them if it rains

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Agreed with others, go disc.

  • It is futureproof and supports resale value as well as more wheel options in the future
  • TT rim brakes are pretty terrible, my rear brake is almost useless in wet conditions. Discs are much safer
  • You can fit wider rims and tires, both of which are more comfy and often faster. I just sanded down a pair of brand new brake pads to 10% to make new wide rims fit.

The claimed drawbacks (mainly difficulty of wheels change and safety in a pack-crash scenario) do not even apply in triathlon.

I just went through this same thing, was looking to get my first tri-bike in the $3000ish range. I decided i definitely wanted disc brakes for a few reasons:

  1. It’s what I’ve ridden on my road bike for years and I’m very comfortable with it
  2. It’s much more future-proof, it seems like everyone is going disc these days in all disciplines
  3. The ability to run wider and tubeless tires more easily, as this also seems to be where everyone is moving.

I actually ended up purchasing a Quintana Roo PRFour Disc during the summer sale. I only ordered the bike a week ago so I don’t have it yet to give you a fulll review, but they were great during the buying experience. Test ride at a nearby bike shop felt great, and QR was really helpful. They can do some customization at no extra cost (e.g. different crank length) and have felt like a really good company so far

This is what convinced me to go with a Tarmac SL6 Pro Disc early this year over an S-Works SL6 with rims…

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$900 more and the only difference is disc brakes? The premium over rim brakes should not be that high. If the rest of the build is similar then you are paying A LOT for that upgrade. I’d agree with what everyone has said above about performance difference. I’m always a slow adopter of new tech and I guess my feeling on road or TT disc is that it isn’t something I would go out of my way to get upgrade for BUT if I was getting a new bike it is the way I would go for all the reasons above.

I almost pulled the trigger a few days ago. Went back to the site and the sale was over. Now I’m contemplating just waiting for a while

Out of curiosity: did you ever have to do this? I have owned bikes with disc brakes for >15 years now, and I never had to bleed my brakes, not when I was flying cross continents and not when I went by car.

Once - somewhat self inflicted. The bike bag i borrowed from a friend was really small. I couldn’t get the bars to sit nicely in the bag without fear of bag handlers damaging the bike frame or tearing the cables so I disconnected the hydro/cables and bars to fit. Once we got to our destination, everyone was circling the parking lot, yelling “lets go”, while I was still bleeding my brakes.

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If done correctly, a flat TT is not easy


mhandwerk: Maybe something got lost in the translation. “Easy” refers to the course and whether it requires a lot of complicated maneuvering and BRAKING. A flat out-and-back with no intersections would be an example, although braking at the turnaround is always a perilous issue. I’m old and have ridden countless TTs and coached world-class riders in TTs and I might understand that all TTs are hard–but so would virtually everyone else in this forum. Furthermore, you had nothing to add to the thread or our understanding of the topic, unlike virtually everyone else who provided helpful comments. It wouldn’t be hard to interpret your comment as snarky but I’ll just imagine you had a perceptual problem that day. Keep calm and carry on.

You used the wrong adjective and I corrected you just to make sure there was not confusion as not everyone is going to associate ‘easy’ with ‘non-technical,’ Especially since there are individuals on this message board in which English is not their first language.

Not sure why you got so offended to write an entire paragraph just because just because of my attempt to place clarification on your post

Do you have any thoughts about the actual question? I’m sticking with my adjective. “Easy” has a lot of meanings and you chose, for your own reasons, to interpret it using only one of them. One that virtually nobody who races a bike would think of using. That’s on you. I hope the original questioner (and the rest of the group) got useful information from my post. I’m not offended (again, misinterpretation is on you), but I am intrigued that you would continue to dig a deeper hole. Parse that statement.

I also considered the ceremony P-series 105 disc. Its discounted a bit here: