Disc brakes vs. Rim brakes on Tri bike???
This will be the first of a series of posts I make trying to determine the "Ultimate" Superbike for the next ~5 yrs of Triathlon racing.
I'm trying to discern the merits of "Fancy new-fangled" Disc brakes vs "Traditional" Rim brakes [For Triathlon purposes]
I raced IMWis last weekend and I think I can count the number of times I even touched my brakes on one hand (definitely single digits). 1 time (light touch) coming down the helix out of T1, One time (for maybe 1.5 seconds) as I approached the off-camber Right on Garfood on the first loop, both loops (maybe ~1-2 seconds) just before the 90 degree left turn at the bottom of the steepest hill, maybe ~1-2 light blips elsewhere as I made a sharp turn at an intersection, and 1x at the Dismount line. At Al-T-Tude camp this year, I ascended and descended 31,472' with my rear rim brake almost completely disconnected and my front brake at ~50% functionality. I "wished" I had slightly better brakes on a handful of times on that camp, but if I had at least 75% functionality of my front brake and even 50% functionality of my rear brake, I wouldn't have ever asked for or desired more on that trip (but arguably it was dry the entire camp). So "If" I have even modestly serviceable rim brakes, I have never felt like I needed better braking on my tri bike (not the case with my mountain bike or fat bike where I am almost always happy to have great breaking).
Disc brakes: I know disc brakes are NOT new technology. My ~8 yr old Mtn bike has them as does my Fat Bike (and almost all new gravel grinders and ~50% of new high end road bikes), so for all of these applications they are clearly the way forward. I'm trying to figure out if they "truly" are a superior technology for Tri bikes. Do I really want superior braking speed while I'm moving at ~20+ MPH?
Disc brake advantages (that I could think of):
1) superior stopping power
2) no drop off in stopping power in wet or mucky conditions
3) brakes won't rub if you break a spoke or wheel is slightly out of true
4) less grip strength required to apply similar stopping power
5) more likely to have a through axle for a stiffer rear triangle
Disc brake dis-advantages (that I could think of):
1) Maintenance (It's super easy for "me" to adjust rim brakes (even mid ride), but not so much with hydraulic disc brakes)
2) Brake rub - highly sensitive to configuration and prone to bake rub (this can be fixed on rim brakes by simply loosening them up as I did at Al camp)
3) Travel restrictions? harder to dis-assemble? Potential TSA issues (anyone experienced with this?) Brake lever might get pulled without the wheel on bringing the pads completely together...
4) On course tech support? I had a friend break his front wheel during IMLP this year. When tech support eventually got to him, they simply swapped him a new front wheel and he was on his way... Do they even carry disc brake wheels for that (in 2018)?
Rim brake advantages (that I could think of):
1) Simple and known entity (I have used them for years and years)
2) Feathering and brake modulation at high speeds
3) easy to align or widen or even disconnect (mid race) if there is an issue with your wheel.
4) maintenance - home maintenance is simple (maybe that's my experience bias)
Unknowns in the comparison (unknown to me anyways):
1) weight? My guess is that the rim brake system is a bit lighter, but this is just a guess
2) Aero? My guess is that rim brakes (on most Superbikes) are more aero as they are almost completely hidden from the wind. However Disc brakes leave more clearance around the wheel/rim frontal area itself which "might" allow better airflow between the frame and the wheel which "might" be slightly better aero?
3) Speed/ease of flat tire changes? Youtube suggests disc brake tire changes are slower, but I don't buy it... Takes me mere seconds to get my wheel off of my fat bike. I'd gladly spend an extra 10-15 seconds removing a through axle if it meant I had a stiffer rear triangle for the 99.99% of the time I'm actually riding.
4) Interesting to me that most Cervelo sponsored Pro's choose the ~6yr old setup of a rim brake and slightly lighter P5 over the Disc brake and slightly heavier P5x. Is this related at all to the brake situation, or weight (are they related), or simply the handling/feel/fit/look of the P5 vs P5x?
What I care about in a brake for Triathlon Racing, in Ranked order of importance for me are:
1) Highest top speed (i.e. more aero)
2) Weight
3) Ability to modulate braking at high speeds (i.e. not lock up the wheels at ~30mph)
4) Easy of use/maintenance
5) Compatibility with on course assistance (but if I need this, my race is probably essentially over anyways)
6) Compatibility with the mainstream future of bikes in say, 3-4 years
7) Actually stopping
What say you EN, Do you think disc brakes on Tri bikes are a superior product and the way of the future on Superbike Tri bikes? Or do you think they are the bike industry giving us something cool and new and shiny to buy that is ultimately putting a square peg in a round hole?
Comments
so many pros and cons.
the first thing you have to remember is that the rim brakes on your P5 are hydraulic and not cable pulled. That alone gives you tremendously more stopping power than traditional rim brakes. Since you and I both have a P5 we have similar experience.
my rear brake is an adjustment issue as I have it set for the wider Disc wheel (not to be confused with Disc brakes) so it's a bit weaker than it should be .
the ONLY disadvantage I see is that in the wet I am definitely nervous about my braking effectiveness. I don't need a lot of braking on IM courses or during Al Camp, but most of my riding is on roads of Northern Westchester where I DO need brakes. I did my my F10 Road bike with rim brakes and was strongly considering the F8 disc. Pinarello was adamant that they weren't building an F10 disc (which was already sitting in their paint shop for testing when they wrote that!)
I think you get better modulation, no brake rub issues tremendous confidence in wet conditions. I have noticed, particularly on my F10, that I can lock up my rim brakes no problem, so I am not sure how much better it gets with discs.
Tthe transpo issue on flights, you can insert blockers/spacers into the disc brake calipers for transit, so no issues if a lever gets squeezed. The service issue on an IM is a moot point, you are no longer racing to get another finishers medal, if you weren't racing XC, once you are waiting for the service guys, your "race" is pretty much over.
The only other issue for me is that right now I have a great assortment of wheels. I'd have to start over on that if I went disc.
as for the technology, I had a rear disc brake on my kabuki 10 spd when i was in my early teens 🤩
Now you're baiting!
My view, for my topography and expected destinations, is that disk brakes are the answer to a problem / problems that I don't have.
There is no Col de Toronto, and most of my riding is on rolling stuff. For the rare annual / twice-annual training trip, I might get to mountainous areas, but the last two years in those settings (where I was entertaining and scrutinizing exactly this question, in real time), I didn't have an experience where they would have offered an advantage. A data point: I rode on some of Al's Colorado roads with a tririg / USE Tula combo (iow, not even close to the best-use example of rim brakes), and was repeatedly satisfied that I should keep this setup. In short... the case hasn't been made for me, personally, to make the flip. Now ... if one were an aggressive rider/racer, or were looking for downhill KOMs, or lived in Malibu at the top of a hill, different story.
If it ended there, I would probably be a little bit on one side of neutral on the issue. Where it presents a very big disadvantage to me (with the underpinnings of the above) is backwards compatibility: I've got a swappable setup of a variety of race wheels, training wheels, backup wheels, and two bikes that I routinely rotate these around. Wheel A on Bike B is trouble-free, and the biggest admin when switching is opening the brake lever a bit. I like / love the system-wide usability that comes with that setup, and it would be an enormous sacrifice to forfeit it, or it would have to have tremendous benefits to consider it. Hard to get past.
Of course, read ^this^ with an awareness of the confirmation bias that I'm bringing into it: I love my steel-framed IF road bike, and there isn't a "long and low" geometry tri disk bike, so I do have some baggage!
Data point - a roadie friend of mine has a 6 yr old pinarello, just ordered a new F10 from our LBS and it's an F10 with traditional brakes. wants to be able to move his wheels around.
I cant help but chuckle at the hypocrisy of the cycling industry. The same companies that sold the masses carbon wheels that don't stop for shit, now want the masses to buy disc brakes for stopping power.
Granted in triathlon you do not need your brakes , until you do need them, and then you probably really need them. I've always been a big proponent for aluminum brake track surfaces over carbon and have stuck with that. Watching first hand @UMHC many athletes trying to stop in the pouring rain (I watched countless athletes go coasting past there support car while trying to stop) convinced me that disc brakes may actually be a good thing.
Being able to swap wheels without having rubbing issues or needed adjustments would be my biggest concern. If I went this way I would probably use one set of wheels which would have to be on the smaller side of optimum for all winds/races.
Its a good question and one I must say I would consider disc brakes if I was in the market for a new bike.
@"Dave Tallo" regarding your backward compatibility issue... If I posed you the following hypothetical question/scenario, would you come to the same conclusion?
Suppose you learned that a Billionaire uncle you never knew you had died and as part of his Will he left you up to a $30,000 allowance for Triathlon upgrades with the following conditions: "You must turn in your current Tri bike and for the next 5 yrs, for triathlon purposes only you can only use the stuff you buy with this one time splurge purchase. And you do not receive any of the left over money if you don't spend it all. You can buy 1 triathlon bike and up to any 3 Wheelsets (that you can only use in Triathlon training and racing). You can also buy a powermeter and aero helmet and any other tri stuff you want.
Would you buy the exact same bike you currently have? Would you buy a Superbike? And more specific to my original post in this thread... Would it have disc wheels?
Good question.
I would buy exactly the bike I have, followed by the Cervelo P4. But I'm clouding the issue because a native 'long and low' fit that (almost only) these bikes feature would continue to be the biggest factor.
If fit were not a factor, it would be the https://www.premierbike.com/products/tactical. It would not have disk wheels.
I've got 4 bikes, all rim brakes and I like the ability to swap wheel sets. For steep and possibly wet courses, I have a set of HED Jet 6+ wheels and Dura Ace C35s both with aluminum rims. The argument between Rim and Disc on carbon wheels is becoming moot considering that the HED Jet Black wheels brake nearly as well as disc. MAVIC is close behind with their Exalith surface.
So there no longer is any need for disc brakes but that is obviously where the manufacturers are trying to steer us. Cons that I can think of:
Regardless, we may not have a choice in another 5 years.
@Dave Tallo No, you don't want a P4. Trust me. The rear brake is absolute shit. Like, terrifyingly bad.
WRT the the point that you don't really brake all that much in triathlon I'd say that it's true that you don't brake all that much in a race but I'm guessing that less than 0.1% of my riding is in a race. The other 99.9% of the time I'm training . Invariably, I'm faced with the dilemma of whether I want to ride my P4 (with it's horrendous brakes) or take the road bike with disc brakes (or ride in Zwift). I think that I probably spent far less time outdoors on the tri bike this past season than I should have, in large part because most of the riding around here is hilly and the P4 is just not fit for purpose for that riding. So in the final race prep phase where I wanted to be on the tri bike 100% of the time, I was on Zwift for 99% of that. Now, if your local riding is all flat, then the equation changes somewhat.
If the rumors of a P5 disc prove to be true, I may sell my entire P4 setup (training wheels, Zipp disc + 808's front and rear) and make the switch.
I've used disc brakes on MTB since 2006, and on my roadie since 2014. My new TT last year did not have them. I am well known for descending like a grandmother - meaning, I like to be careful on long or twisty descents. I love the discs on my roadie - very consistent modulation, no grabbing, minimal effort (a plus for me d/t weakened hands), works the same rain or shine (another plus in the Pac NW). So having raced on my new TT ride for a year, do I regret not having discs? To me, the only criterion is, "Am I going any slower with the rim brakes than with discs?" I do not know the answer to that question. All the other potential pluses are dwarfed by my desire to get all the mileage I can from my inevitably decreasing watts.
As to travel with discs - I've take and shipped my roadie a number of times. No TSA issues, no packing issues, either in the Hen House, or in the eBike cardboard box I've used.
Maintenance - My half-yearly free-for-life tune-ups from the LBS seem to be all that's needed.
Five years down the road? There are too many retro-grouches among roadies to think that rim brakes will disappear that quickly, at least at the high end of the market.
@John Withrow - I replaced my 2013 Specialized Transition with rim brakes with a Quintana Roo PR6 Disc and I will never ever ever go back to rim brakes. I was always adjusting the rim brakes to not rub or squeak. I've had the PR6 all summer and have not had to make a single adjustment. I have had no issues getting them on and off. I cannot see why anyone would prefer rim brakes except for people who still like CDs, 8 tracks and cassette tapes.
Was hoping @Brian Hagan would chime in here. Great feedback from someone who owns disc brakes on tri bike. Brian what is your wheel set up?
I am not sure the actual depth, but they are Reynolds Strike. I also have a through axle that requires a 6 allen Key to tighten / loosen. That is the one part that will take a little longer when going to change the tire. The PR6 has one in the storage compartment, but i keep another one in the bento box. The know the rear is a 25.
I used to be a big disc brake fan; I have them on my road commuter bike, and regretted not being able to get them on my tri bike. But I now lean toward rim brakes for a couple of reasons:
Living in the pacific northwest, and doing a fair amount of riding on hills in the rain, I worry a lot more about tire-pavement friction than brake pad-rim friction.
I do think disc brakes have advantages for some situations like mountain and cross. But for my tri bike where I am putting most of my miles (and doing more maintenance as a result) I'm glad that I have rim brakes.
I agree that it would be annoying to have the brakes always squeaking, but none of the 4 bikes I have now (all with rim brakes) and none of the bikes I've owned before (all with rim brakes) have EVER squeaked. You must have had a lemon. So although I've moved beyond CDs, 8 tracks, and cassettes, I'm going to stick with the tried and true rim technology and skip having to carry an allen key for a thru axle. :) But your PR6 looks great!
So yesterday, I did my "neighborhood ride" on my tri bike, which I brought out here to train with in CO, since I have IM AZ on the radar. 22 miles, 4,000 vertical feet, in a series of climbs and curvy descents of 6-10%, 500-1000' each.
I discovered what @tim cronk is talking about with the carbon rims on my PRSix with those Reynolds spike wheels. It was the opposite of smooth. Grab/release/grab/shudder. Felt like the rims needed to be scrubbed clean.
Of course, I bought my bike just before QR started offering the disc option. If there's a race in your plans which *requires* serious braking on steep, technical descents, then discs would be a big bonus. But, if the course is, say IM LP (Keene descent) or Kona (Hawi descent), I don't think @John Withrow would need them.
@AlTruscott - as I noted above, disc brakes are attempting to solve a problem that some manufacturers already solved (e.g., HED and Mavic). So yes, you can have rim brakes and outstanding braking. Here's a review on the HED Blacks. And only Enve 7.8s have tested faster than HED Jet 9 Black in the wind tunnel.
One-finger braking
Speaking of braking, it's a no-contest comparison between the strength and dependability of the Jet 6 Blacks and even the very best carbon clinchers, such as ENVE's new SES models or Zipp's new NSW hoops with their Showstopper brake tracks. HED uses a machined and anodized treatment similar to Mavic's Exalith, where a finely textured track provides heaps of traction for brake pads to dig into.
I was able to descend steep hills here in Colorado with a single finger on each lever as if I had discs brakes, compared to the typical all-four-finger-death grip that descents like Magnolia often require. My colleague Guy Kesteven found the braking "even in the shittiest UK conditions" to offer way more modulation than Exalith. "And you're not actually embarrassed to pull the lever," he said, referring to the noise often associated with Mavic's brake surface.
And, yes, the brake track is black, so combined with the black fairing the wheels appear at a distance to be all carbon. But when descending in the rain, there is absolutely no way you could confuse the two.
http://www.cyclingnews.com/reviews/hed-jet-6-black-review/
I was hoping this would develop into an interesting discussion. And it has... However, most of the focus and attention seems to be on the thing that was #7 on my list of 7 things that I mentioned were important to me...
What I care about in a brake for Triathlon Racing, in Ranked order of importance for me are:
1) Highest top speed (i.e. more aero)
2) Weight
3) Ability to modulate braking at high speeds (i.e. not lock up the wheels at ~30mph)
4) Easy of use/maintenance
5) Compatibility with on course assistance (but if I need this, my race is probably essentially over anyways)
6) Compatibility with the mainstream future of bikes in say, 3-4 years
7) Actually stopping
Seems pretty obvious to me that Disc breaks stop better (so for someone like @Al Truscott with residual injury hand strength issues, seems like a no brainer). But as @Paul Hough points out, there are some really good stopping Rim brakes, but my 5 yr old Zipp FC 808's brake good enough for me... Or my training wheel FC303's, even on my road bike with ~6yr old (non-hydraulic) Ultegra rim brakes...
The answer's to #1 and #2 above still are not obvious to me... Are they more or less aero? is there a weight penalty/advantage? #4 seems to be advantage Rim brakes, but not by much. #5 to @scott dinhofer 's point probably a moot point if you're "racing to win" as opposed to "finish".. #6 is still an unknown to me, but sure feels like this is where the manufacturers want to push the industry (not clear if there is a common standard yet or if the wheel manufacturers have kept up with the frame makers).
Would love to hear if any of you have opinions on my the paragraph above. Otherwise, seems like it's still a toss-up and something that shouldn't actually factor into my final decision to what new Superbike I try to built/buy next.
@Paul Hough Thanks! Maybe I should get ne of those HEDs and give it a try...
My buddy has a P5x. It did pretty well in the ST aero bike shootout. I have a P5. I try to keep it as bare as possible, but with any extra doodads hanging off the P5 the P5x becomes the leader. Another confounding issue is/are tubeless tires on disc-brake wheels. IF they roll faster and sealant gives them a puncture advantage, maybe with disc brakes lower frontal area/shrouded caliper they could prove faster? I don't have any answers to these questions, but I bet this is what will drive my next bike purchase.
if you haven't seen it @John Withrow , there is a good thread on ST highlighting the new bikes rumored to be coming next week around Kona.. note that not all of the following "upgrades" are "truth," all are rumors.
Specialized Shiv - disc brakes, new downtube shape more boxy like the dt on a pinarello F10/bolide, storage compartment like the Trek SC
Cervelo P5 Disc with the cockpit of the P5X, On Cervélo’s website, there’s a new landing page for the P-X series, which would suggest a new line of P-X bikes to be revealed
Quintana Roo - PRFour Discs
Felt - updated IA with discs and rumored internal hydration bladder
Pinarello - updated Bolide (will require a JW hedge fund account to afford) Discs, storage & hydration compartments.
Giant - expected update to the Trinity advanced Pro 0
while I know i can lock up my rear wheel in my P5 calipers... you've got me thinking... but then again, I am hoping to retire from IM and move on to more adventurous events after next year 😁
Pinarello Bolide
@scott dinhofer I retired from racing Ironman in 2016... But here I am. I've been following that ST thread closely and agree that most of those "rumors" will likely be confirmed or debunked within the next week or so.
I don't know if I can wrap my head around that new Shiv. I am anxiously awaiting the arrival of the new P5-disc. And I won't lie, that Pinarello is just plain sexy! If I sell my boat I can probably buy it without Jess noticing how much it costs.
Does anyone want to buy a boat? I'm actually not kidding, it's for sale...
But to confirm the Original idea behind this post, it seems like the "shiny New Object" on literally all of the new Superbikes is the disc wheels, so it looks like we're definitely heading in that direction whether we want/need it or not!
I have disc brakes on my mountain bike - love them. Also on my Road bike for all the advantages that you mentioned PLUS my road bike needs match those advantages. If I build a gravel bike, I will definitely put disc brakes on it.
I don't ride my tri-bike when I go out west / or to Blue Ridge and i don't think they add anything for me. Hell - I try not to stop when I ride my tri-bike. I have Tri-Rig Omegas that I really love on my TT bike.
One thing for you to consider... you do take your tri bike to the mountains etc... so it is possible that you would appreciate your list of advantages more than some of us because you ride your TT bike in a lot more situations than some of us do.
You could start an equally interesting conversation thru-axel vs skewers... I see these as another solution to a problem I don't have on the TT bike.
I just bought a shiv s-works. I knew they'd be coming out with a disc version soon enough, but couldn't wait to pull the trigger.
I have too much $$$ invested with rim brake wheels now to switch over. I switch race and training wheels between my road and tri bikes. Eventually, I'll know I have to switch over, but it'll be another extensive cost investment, because I had to get custom built wheels for my fat arse (production-ready wheels always break for me).
@Rich Stanbaugh If I were to design a custom Tri bike frame, it would have the aero stats of the Cervelo P5 or P5x, it would have a wide chain stay like the QR PR5. It would have a super stiff Bottom bracket area like the Ventum, It would be super easy to take apart for travel and easy to work on (like most road bikes). It would have rim brakes (after this thread). But even though it would have rim brakes, it would use a Through Axle! Because I think it would simply make for a better/stiffer rear triangle (even at the expense of an extra 15 seconds per wheel change).
And since I'm dreaming, it would have zero exposed cables or brakes, and the electronic control unit and battery would be hidden inside the frame, but be very easily accessible. It would also have a removable front derailleur hanger with a cover that would make the spot invisible to moving air or the naked eye if the FD is removed to make it a 1x bike. It would also have integrated storage for a simple flat kit and integrated bento and standard bosses for bta hydration.
Oh, and it would only weigh ~16.0 lbs fully built!
And since I'm dreaming, I'll also get Wireless Electronic 1x12 speed shifting with a clutched Rear Deraileur that can be configured on said triathlon bike!
aside from the through axle, it’s sounding a bit like the Premier tactical ....