Would you buy a frame/bike with post mount brakes? [Archive]

roguedog

03-02-2019, 11:18 PM

kppolich

03-02-2019, 11:41 PM

Bigger question to me would be is it QR or TA?

Would I buy a TA, Post Mount - yes.
Would I buy a QR disc anything at this point - probably not.

Andy sti

03-03-2019, 12:37 AM

I don't think you'll have any issue. You can always sub in a post mount caliper. Not an issue at all. Once you have brakes on there it's not like you'll need to change them anyway.

Clean39T

03-03-2019, 12:53 AM

QR Disc?

If the frameset was made by a builder I trust (Wages, Kirk, Strong, Sadoff, Holland, No. 22, Firefly, etc.) - yes.

Like this one, perhaps:

https://lh3.googleusercontent.com/-JOhfE0lCZys/Vtm-e4cEbcI/AAAAAAAAL8I/OCzpKcrT9Rk/s640-Ic42/IMG_0812.JPG

.
.
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But if it was an off-the-peg carbon setup - probably not.

Morgul Bismark

03-03-2019, 02:39 AM

At least with the current shimano and SRAM road groups, I'd say not much of an issue at all. Both have post mount brakes that work with their newest groups.

In the case of my Breadwinner B-road (https://forums.thepaceline.net/showthread.php?t=232698), I'm using RS785 brakes with R8070 levers.

eTap AXS has both post mount and flat mount options too.

R3awak3n

03-03-2019, 06:14 AM

Only if I absolutely loved the frame or was a really good deal.

At this point I would definitely not buy QR disc, I think TA is awesome for discs, specially in the front, the back QR is fine. As far as mounts, I dont think flat is better in anyway than post exept that it looks better but if I was buying a new bike today I would want what will be the future of discs.
I am glad sram is doing post for etap, campy has no post mount though so say you wanted to put that you goong to have and spend an extra $200 on hope calipers. I feel like more companies will start abandoning post.

But like I said, the deal is right, the frame is special I would still consider it

charliedid

03-03-2019, 06:24 AM

This is a good read: https://www.bikehugger.com/posts/road-disc-brake-tech-flat-mount-vs-post-mount/

quickfeet

03-03-2019, 06:26 AM

Not having thru axles is more important than post vs flat mount right now. There are adaptors to make post work on flat mount frames. Parts manufacturers are essentially done producing post mount going forward but that just means deals can be had on previous gen post mount parts.

fignon's barber

03-03-2019, 07:37 AM

Curious, if a bike/frame came up that you were interested in but it had post mount brakes vs flat mount, would you buy it?

What are the downsides of purchasing bike/frame with post mount? Is it just that you will have issues with newer groups moving forward?

No doubt it will be harder to resell. But if you like it,go for it. Hell, I was just looking at a frame with, gasp, rim brakes!

roguedog

03-03-2019, 08:46 AM

I also would also not flinch at buying a rim brake bike. I feel like they've been around so long that parts and finding parts wouldn't be a problem. Also, it speaks to my personal preference. I like the simplicity of rim brakes and the aesthetics.

It's that disc brakes haven't been around for road bikes for too long and standards have already shifted.

I assume then that post mount road bikes prices would reflect the generational shift?

Also, it seems that functionally folks are saying that post mount brakes aren't worse or some how less good than flat mounts. It's just an aesthetic thing?

Interesting on the QR vs TA .. good point. So you all are saying the same thing with regards to wheels, that it will be hard to find disc qr rims given the shift there as well.

Side note: Damn, Clean, I love that bike.

XXtwindad

03-03-2019, 09:13 AM

This one.

I bought it because I thought it looked stunning and got great reviews. The QR front (a fork only made a few number of times by Alchemy for this specific frame) concerned me a bit, so I did some research, and talked with some Forum members. Everything indicated that QR front is no problem for the road, which is where I'm going to use it.

If I want to switch to gravel/hardpack, I would switch out the fork, which isn't an issue, because it's a 44mm head tube. That would slacken the geo a bit, which would be better for gravel.

QR back isn't really an issue...

Hope that helps.

XXtwindad

03-03-2019, 09:15 AM

I also would also not flinch at buying a rim brake bike. I feel like they've been around so long that parts and finding parts wouldn't be a problem. Also, it speaks to my personal preference. I like the simplicity of rim brakes and the aesthetics.

It's that disc brakes haven't been around for road bikes for too long and standards have already shifted.

I assume then that post mount road bikes prices would reflect the generational shift?

Also, it seems that functionally folks are saying that post mount brakes aren't worse or some how less good than flat mounts. It's just an aesthetic thing?

Interesting on the QR vs TA .. good point. So you all are saying the same thing with regards to wheels, that it will be hard to find disc qr rims given.

Side note: Damn, Clean, I love that bike.

A lot of hubs (i9 for example) can be switched out.

prototoast

03-03-2019, 09:20 AM

Also, it seems that functionally folks are saying that post mount brakes aren't worse or some how less good than flat mounts. It's just an aesthetic thing?

Two small advantages of flat mounts on the chainstays -- access to the bolts on flat mounts is from the bottom, which avoids interference from the seatstays. With post Mount brakes, particularly on smaller frames, accessing the bolts can be a challenge sometimes.

Another advantage is it remove the threading from the frame. This isn't a huge issue, but if you botch an install/repair with post mount brakes, you can end up damaging the threading in the frame. With flat mount, the bolts go into the caliper which makes the frame virtually immune from incidental damage during install.

I wouldn't consider either of these issues to be deal breakers, and braking performance is identical in my experience, but if everything else were equal, I'd prefer flat mount for more than aesthetic reasons.

charliedid

03-03-2019, 09:20 AM

I also would also not flinch at buying a rim brake bike. I feel like they've been around so long that parts and finding parts wouldn't be a problem. Also, it speaks to my personal preference. I like the simplicity of rim brakes and the aesthetics.

It's that disc brakes haven't been around for road bikes for too long and standards have already shifted.

I assume then that post mount road bikes prices would reflect the generational shift?

Also, it seems that functionally folks are saying that post mount brakes aren't worse or some how less good than flat mounts. It's just an aesthetic thing?

Interesting on the QR vs TA .. good point. So you all are saying the same thing with regards to wheels, that it will be hard to find disc qr rims given.

Side note: Damn, Clean, I love that bike.

Some people believe that post-mount has the edge when it comes to adjustability and compatibility across the widest range.

Many pro mechanics I know believe this.

FriarQuade

03-03-2019, 09:41 AM

Flat mount is the dominant fitment for road bikes. But it's not better. Lot's of builders big and small are struggeling with alignment.

Hilltopperny

03-03-2019, 05:08 PM

I have used both flat and post mount brake set ups and I could not tell any difference in the braking. I would not hesitate to pick up another post mount bike as long as the intent was to keep and ride it.

Sent from my XT1650 using Tapatalk

pdmtong

03-03-2019, 06:47 PM

if you were to wait another 18-24 months and ask the same question, the answer you will get is flat and TA.

we are only talking about post and QR because the shift is still happening.

rim will be around for quite awhile because it's traditional, simple and light.

mattsurf

03-04-2019, 02:39 AM

The M9000 XTR Post mount Calipers on my Gravel bike are lighter and better than the BR8070 flat mount calipers on my road bike

thermalattorney

03-04-2019, 08:39 AM

The M9000 XTR Post mount Calipers on my Gravel bike are lighter and better than the BR8070 flat mount calipers on my road bike

+1 My experience with R785 vs R8070 calipers was similar. The post mount ones had larger pads and worked slightly better.

I wouldn't hesitate to buy a post mount frame. You'll have access to compatible brakes for years to come from either Shimano or SRAM. Heck the one thing that AXS didn't break compatibility with was their calipers.

GPrince

03-05-2019, 04:52 PM

I'm riding thermalattorney's R785 right now. Work just fine.

And for me..price was a strong factor. I picked up a QR disc Seven Evergreen SL with nice wheels and an Enve CX fork for $1k. Can always convert the fork later.

KVN

03-09-2019, 09:30 PM

There’s a lot of compromises that are made on flat mount steel frames and forks. I think i’d actually spec post mount if I was ordering custom steel. Less of an issue with carbon.

ColnagoC59

03-10-2019, 08:58 AM

does post mount work any less well? if not why should i care? just asking.
thinking this is mostly aesthetics for road bike applications

unterhausen

03-10-2019, 09:09 AM

does post mount work any less well? if not why should i care? just asking.
thinking this is mostly aesthetics for road bike applications

I think people are worried about future availability of calipers for road post mount applications. I think the steel flat mount rear dropouts available to me are ugly, but I'm getting used to them. For whatever reason, there is very little flat mount support for builders making steel forks, which IMHO is much better than post mount in that application.