# Plate style dropouts vs. hooded style? (semi troll)



## febikes (Jan 28, 2011)

Okay this is somewhat a troll but also a quest to learn something by understanding the design thinking of others.

Some people must like plate style dropouts. 

It could be that I am missing something but why do people use the plate style drops?

Are there advantages vs. hooded?

While we are at it is there any advantage for using chainstay mounted brake vs. seat stay mounted in the context of a performance oriented steel hardtail?

We all have preferences for style but when you get down to performance issues what are your thoughts?

My thinking is that when push comes to shove a plate style is weak and doing the the brake mount as part of the chainstay only makes the problem worse unless a crazy heavy plate is used. 

Like I said, I could be missing something. Plate style is a little cheaper but is there any other advantage? The only thing I can think of is that it may be easier to bend them back after they bend out in a crash.


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## Walt (Jan 23, 2004)

*My reasons*

Random thoughts, as someone who uses both but *mostly* plate:

-With the exception of 40 year old Raleighs (and those Niners with the dumb machined out dropout + derailleur hanger from a few years back that I've fixed a zillion of) bikes don't tend bend or break at the dropouts, so strength is not really an issue. I'm sure you could make an argument that the attachment to a hooded dropout is stronger but some other part of the frame will be toast long before it matters.

-Many people are just more comfortable with tab type/plate dropouts. I think a big reason for this is that you can cut your slot a little too long and the chainstay is still usable - if you cut your miter too short on a hooded setup it's often no longer of use.

-Plate dropouts allow some "expression" (ie points, scallops) on the part of the builder and can be joined with any (silver, brass, TIG, etc) commonly used joinery technique. I guess in theory you can do fillet with hooded dropouts but it's difficult and you need a lot of hood to work with.

-In many cases for unusual bikes (ie 29ers, fatbikes, etc) the tab allows the use of many more models of chainstay than a hooded dropout due to the length of the tab. That can be very useful.

-Plate dropouts often have the disc mount integrated to the dropout so that you don't have to do another step and join the tab to the frame (whether chainstay or seatstay). For seatstay mounted disc tabs the seat/chainstay load sharing can also be done by the dropout so you don't have to build/join a bridge. So they are a timesaver for many people.

-When I did a head to head comparison of using Breezers+disc tab+brace to using Paragon DR2010, I found that the weight difference was pretty negligible. I can't recall specific numbers but I think the difference was in the 10-20g range. Not really a big deal IMO.

-If you do need to replace a dropout, plate type ones are pretty easy. Hooded, not so much (I've had to do it, it sucks).

So bottom line, for me - I choose the dropout I think is best for every specific situation, but a lot of the time that's a plate dropout. We are lucky to have so many choices these days and almost all of the dropouts you can buy are awesome so build with whatever you think is cool.

On the chainstay/seatstay thing, I don't think there is any "performance" advantage unless you want to mount a rack and a seatstay mounted caliper will be in the way of doing that. Both will stop you just fine, neither is going to save you any incredible amount of weight or allow the bike to survive some crash it otherwise wouldn't.

-Walt



febikes said:


> Okay this is somewhat a troll but also a quest to learn something by understanding the design thinking of others.
> 
> Some people must like plate style dropouts.
> 
> ...


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## unterhausen (Sep 28, 2008)

when I started building there were only plate dropouts and I feel most comfortable with them. If the tube is past a certain size (which I am unsure of) then hooded dropouts make a lot more sense than plate dropouts. But even then there are a lot of working examples of both.

To reiterate what Walt said about dropouts, all you have to do is go look at an old Huffy or AMF to see how unlikely dropout failure at the joint is. I fixed a lot of crappy frames BITD, and never once did those silly spot welded dropouts have a problem. When domed chainstays were common there would occasionally be a failure when the dropout wasn't brazed in, but that pretty much goes without saying.


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## MDEnvEngr (Mar 11, 2004)

To my eye the hooded dropouts work best with TIG and the plate style work best with brazing. Going the other way seems to create additional joining fuss. Reference the caps and plates and other tube closure methods that the TIG guys do on plates. I've used the hooded drops a number of times with brazing, but never liked the result. B


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## febikes (Jan 28, 2011)

Thanks guys, I feel like I am learning a bit...

But I am still trying to troll......

Consider 204g...








Vs. 61g and 48g















A failure example from some random thread.








It sure seems to me like a hooded drop with a seat stay brake mount and tubular/hood construction would not have bent like that. I also think a hooded drop would be stiffer while pedaling and give the rider better power transfer. A longish plate with little support does not IMHO seem like it can handle the same level of stress as a hoodie. My guess is that a hoodie drop would have been fine and the axle would have snapped without any bending or distortion of the dropout.


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## Walt (Jan 23, 2004)

*It's still not as much as you think.*

Ok, on the weight thing: you've got an extra 150mm (75mm on each side) of chainstay and 50mm of seatstay (or something like that) to use with your hooded drops. Using moderately light stuff that's a solid 70-75g, meaning that your weight advantage has dropped to 20g or so - and that assumes you are going to somehow mount your disc tab on the chainstay or something with your hooded setup. If you need a crossbrace (seatstay mounted) then it's a wash again.

I would bet dollars to donuts the picture you reference has something to do with the rider not tightening down the QR and having the wheel come partially out while riding. EDIT: If you look closely, the hub axle has broken. That would also do horrible damage to a hooded dropout, IMO.

Hardtails are insanely stiff, and transfer power really, really well. No dropout choice will change that in any meaningful way, so don't worry about it.

Bottom line is still build with what you like. I've done hundreds of bikes
with both and I like both in different situations but *for me* plate tends to be the way to go. YMMV.

-Walt



febikes said:


> Thanks guys, I feel like I am learning a bit...
> 
> But I am still trying to troll......
> 
> ...


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## febikes (Jan 28, 2011)

Walt said:


> Ok, on the weight thing: you've got an extra 150mm (75mm on each side) of chainstay and 50mm of seatstay (or something like that) to use with your hooded drops. Using moderately light stuff that's a solid 70-75g, meaning that your weight advantage has dropped to 20g or so - and that assumes you are going to somehow mount your disc tab on the chainstay or something with your hooded setup. If you need a crossbrace (seatstay mounted) then it's a wash again.


I agree, it's likely a total wash in terms of weight.



Walt said:


> Bottom line is still build with what you like. I've done hundreds of bikes
> with both and I like both in different situations but *for me* plate tends to be the way to go. YMMV.


Very true!

Thanks for playing, I learned a bit.


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## TrailMaker (Sep 16, 2007)

Walt said:


> I would bet dollars to donuts the picture you reference has something to do with the rider not tightening down the QR and having the wheel come partially out while riding. EDIT: If you look closely, the hub axle has broken. That would also do horrible damage to a hooded dropout, IMO.


Sorry;

I like them both, so you'd be out both dollars and donuts. I have probably been one guilty of over tightening my skewers as long as I've been riding. The fact that I have never snapped one is probably more luck than anything, but perhaps I've not been too bad. In any event, the pic used here clearly shows that the axle is firmly in place. The other side looked the same way. I did not touch any of this until I got back to my shop. Releasing the lever at that time had no effect on the wheel's position. Since the skewer was also bent, I had to turn the nut off the drive side, and when I did it still did not move. Giving the tire a bash with my hand saw the wheel leap out of the DO slot. Rest assured that out on the trail, the wheel did not move relative to the DO, AT ALL!
-------------------------------------------------------------------------------------------------

The real salient question here is how would a hooded DO system have reacted? If you consider the tremendous force exerted when an already snug chain climbed to the next largest cog - effectively trying to shorten the distance between the crank and axle - it is obvious that something had to give. I wish it had been the chain, but it was only a couple of miles old. It was the axle. It let go, but the skewer held things together as the axle nut jammed into the cassette. When all of the free angle available for that stuff to move forward was exhausted, the DO was next in line. As bad as it feels and looks. I am quite glad that the damage was restricted to the DO itself, and not the stays. THAT would be a true disaster.

Given that a hooded DO has no real length or "sacrificial" material with which to absorb a load like this, I shudder to think what that might have done to the stays. After the axle/skewer, would the chain have been the next failure in line with hooded DOs? Given the tremendous amount of work to repair the damage from buckled stays, you'd certainly hope so!

I don't think I'd bet dollars, nor donuts, nor my powder coat on it!


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## unterhausen (Sep 28, 2008)

thought I recognized that chainstay, sorry to hear about the failure. The ramps on cassettes have their advantages, but running singlespeed isn't one of them.


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## febikes (Jan 28, 2011)

TrailMaker said:


> Sorry;
> Given that a hooded DO has no real length or "sacrificial" material with which to absorb a load like this, I shudder to think what that might have done to the stays. After the axle/skewer, would the chain have been the next failure in line with hooded DOs? Given the tremendous amount of work to repair the damage from buckled stays, you'd certainly hope so!


Yes, I think you have hit the nail on the head. It is an interesting question for what is likely a super rare event. Failures like this are rare but they let us look at design with a critical eye.

I think that on your bike your DO bent first and the axle snapped later on. My guess is that the hood drop/stay would be fine and the axle would snap to release the load without damage to anything but it is hard to be sure. The chain is crazy strong for this type of loading so I don't think it would fail. I have had sticks sucked into my chain on my single speed that stopped me from pedaling with no damage to anything in the system.

I am planning on running 142x12 through axle for future bikes. With a through axle the axle failure would take a lot more force. My hope is that the loading would simply stop the rider from pedaling but I don't have any data to back up that theory and like you say nothing would be sacrificed until the stay, chain, cog, or free hub broke down.

It's an interesting problem to think on with no clear answer.


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## TrailMaker (Sep 16, 2007)

febikes said:


> Yes, I think you have hit the nail on the head. It is an interesting question for what is likely a super rare event. Failures like this are rare but they let us look at design with a critical eye.
> 
> I think that on your bike your DO bent first and the axle snapped later on. My guess is that the hood drop/stay would be fine and the axle would snap to release the load without damage to anything but it is hard to be sure. The chain is crazy strong for this type of loading so I don't think it would fail. I have had sticks sucked into my chain on my single speed that stopped me from pedaling with no damage to anything in the system.
> 
> ...


Actually;

I think you may have cleared it a bit. I think I may agree with your assertion that the DO bent first. I can certainly see it being the case, at least in theory, but it really did not occur to me until you said it. Someone with a lot of time on their hands could sit down and calculate the difference in circumference between 2nd and 3rd gears, but whatever it is, it certainly presents a massive load for the components involved to deal with.

If a chain is indeed stooopid strong in this instance, which it is, and would not be likely to fail in any event, then it still begs the question of where would these forces "go" given a hooded DO? Sacrificial parts like replaceable hangers and maybe even aluminum axles exist quite on purpose in many designs, of course. The hooded DO itself has virtually no material to sacrifice like a plate style does and the joinery of a round tube to a "perpendicular" flange is theoretically very strong. If the DO does not give, the skewer/axle are still wanting to dissipate their load somewhere. Does the skewer give first? The axle cap spud is still in the DO slot. Does it slip out or snap the axle off like it did on mine? How much will the chain take, either in brand new or variously used condition? If none of this happens, that force most likely has to go into the stays, and how much will they withstand?

For me, this was a case of just having settled in for a long steep technical climb. There was no way to back off that much resolve that quickly once the resistance was felt. In a normal situation where a stick gets lodged in things, maybe I could have backed off in time. Most of us - the smart ones - have learned to do that under normal circumstances. Whatever the case, in my circumstance, it is entirely possible that given what happened and how, the outcome here was actually the best that could be hoped for. Hard to say.

While I still think the DO could be a tad thicker, I don't blame it at all. Part of me would like to try this same experiment with a hooded DO. Except for the fact that Murphy's Law would likely stipulate that, if you are purposely trying to get something to fail as a test, when you have already sustained a similar accidental failure, the test will be for naught, as you won't be able to repeat the failure for the benefit of knowledge, under any circumstance!


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## unterhausen (Sep 28, 2008)

I had to get used to those long paragon dropouts. They are a fairly extreme example of a plate dropout. There really is nothing stopping them from making a hooded variant of the same design and it would have the same buckling mode failure under the situation where a chain all of a sudden got forcibly shorter


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## febikes (Jan 28, 2011)

I generally like the Paragon products but their low mounts seem totally lame to me.

The Surly ones are hooded and look way stronger even based on this poor photo.








Also, note that it looks like the only do the long drop on the non-drive side. It also seems the 3D edges on the drop would make them stiffer vs. a flat plate.



















I am still not a fan of low mount drops but at least the Surly ones don't look all totally wimpy.


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## zank (May 19, 2005)

The only reason I'm not a fan of hoods/breezers is that some QR levers can't be positioned out of the way and where I like them, ie between the stays.


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## dr.welby (Jan 6, 2004)

You can choke up on those Paragons:


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## Feldybikes (Feb 17, 2004)

zank said:


> The only reason I'm not a fan of hoods/breezers is that some QR levers can't be positioned out of the way and where I like them, ie between the stays.


And hoods make it harder to mount a Burley. I made an adapter (just a cylinder with a hole) that I use with a tandem skewer so it will clear, but it's sorta ghetto. I realize this is a total non-issue for some people, but it can go from a total non-issue to you're whole life in a hurry.


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## TrailMaker (Sep 16, 2007)

Also;

I'm not overly experienced by any means, but it seems to me that the hooded DO usage would be somewhat limited to situations where tire/crank/stay clearance - and the tube manipulations necessary to achieve it - were not particularly challenging. "Skinny" tired bikes, mostly. For instance, I had to kick the stays out fairly early to get disc clearance on my first frame (the Humvee). I have moderate shoe contact with them as a result. The use of the long plate style allowed me to run straight back from the tire bend to the DO, and come in inside of it; something that would have been impossible to do with a hooded type. incidentally, after the carnage-limited ride recently, there is not a singe shoe mark on the stays anywhere.

There's a place for both. The plate style may seem a but anachronistic in these days of high tech, but they are "the standard" for many very good reasons, and will likely remain so.


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## febikes (Jan 28, 2011)

Good point about heel clearance.

Heel clearance is also impacted mounting the brake on the chainstay vs. mounting it on the seat stay.

What is the thinking about mounting a brake on the chainstay vs. the seat stay? I can see that it means you don't need to install the brace tube but it seems the loss of heel clearance is a big factor and the weight difference between the two mounting styles is a wash. 

There is an advantage for chainstay mounting in terms of installing a rack but that problem can be solved by just using a rack that is designed to mount slightly differently.

It could be that chainstay vs. seatstay is just style or that there is something I am missing but what I see is less heel clearance and a longer plate for more flex/bending problems. It seems seat stay brake mounts are better but they are also starting to become somewhat less popular.


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## unterhausen (Sep 28, 2008)

febikes said:


> The Surly ones are hooded and look way stronger even based on this poor photo.


it's funny how different our mental model of something's strength can be. I see those Surlys as having a significant issue with fatigue at the junction of the plate with the hood. There is precedent for that. Pretty sure you can find pictures of broken hoods on this forum. I've seen plenty of pictures of broken plate dropouts too, but that's almost always at an adjustment screw hole.


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## TrailMaker (Sep 16, 2007)

Hey;

In my case, the mounting position of the caliper was immaterial to me. Having said that, I REALLY like the look of the low mount, particularly on this frame of mine. The real limiting factor for heel clearance is the rotor, not the caliper. Also, the angle of the upper stay tab matched my stay layout perfectly. Even though I could not find a typical high mount DO with an upper stay tab that was at the proper angle for my frame design, I was trying to talk myself into using the segmented stay below to get around the rotor with a straight-back CS. In the end I just could not quite bring myself to do it, and suddenly the PMW low mount sprang into my consciousness.

*G-reg* has raced his recent fatty, and reported that the low mount seemed to collect a lot of snow, where a high mount had not in his recollection. I don't remember whether he said it effected brake performance or not, but the potential is certainly there. The low mount DOs are not without their issues - as with anything - but they seem to be a reasonably viable alternative.

Maybe if I screw up my courage enough to try this style of CS, I will do so with one of your cherished hooded DOs. 
They would be a perfect fit for this style CS!


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## seat_boy (May 16, 2006)

+1 on this, you beat me to it.



Feldybikes said:


> And hoods make it harder to mount a Burley. I made an adapter (just a cylinder with a hole) that I use with a tandem skewer so it will clear, but it's sorta ghetto. I realize this is a total non-issue for some people, but it can go from a total non-issue to you're whole life in a hurry.


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## G-reg (Jan 12, 2004)

I know (especially TIG) builders preferred the hooded PMW sliding drops because they were stiffer/stronger. 

But there are a crap ton of the plate style sliders out there, many (cough*Kona*cough) are lesser quality knock offs. What if we apply the same internets-engineer scrutiny to the plate sliders that the PMW Low Riders have been getting. You hear complaints about sliders being flexy or slipping, but I've not come across any catastrophicfireball failures.



Pic stolen from the internets...think it's a Spot


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## LemonFool (Mar 20, 2012)

I actually see the hooded DO with more question than smaller plate style. I just see a cantilevered force with a square underside edge and picture bending stresses all along the inner side. But, the forces in the seat stays are supposedly not very high. It didn't stop me from making some for my first bike (easy to machine), although they're beefy at something like 200g. I imagine the life span is on par with any other first bike mistakes. 

I don't see a small plate style, centered in the tubing, having any problems other than bending from an impact (or an unfortunate broken axle on a sweet project). When you get into those big Surly and Salsa DO that swoop up I think you're talking more about aesthetics and brand recognition than other factors. Deviation from that line connecting the axle to the frame starts to pick up bending stresses quickly. However, that's why they have engineers. They can look at the trade-offs and study the stresses to know what they can get away with. I mean, they get away with short head tubes, right?


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