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  #1066  
Old 07-06-2018, 10:08 AM
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David Kirk David Kirk is offline
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Originally Posted by Climb01742 View Post
Dave, what are your thoughts about rim vs disk brakes? I may have entered my old foogie stage, but I’m having a hard time wrapping my head around disk brakes. If I rode in the rain a lot, I could make the leap. Otherwise, I’m struggling. Is there something about a disk brake frame I’m missing (he asks almost assured he is missing something). Thx!
That's a big question and I have trouble with a simple answer. I think both rim and disc brakes are great and that one isn't better than the other. That said I think certain brakes are better suited to a particular application.

I think if you want to use a tire that's too wide to fit under a brake caliper, you are riding in the slop, snow or rain consistently, you are riding in the high mountains with long steep descents while using carbon rims.....etc.....then disc brakes are probably the better choice.

If you are riding on flat or rolling terrain, in the dry, with tires that aren't super wide and your biggest braking concern is not hitting your garage door when you get home then rim brakes might be the best choice.

Each brake type is a compromise. Disc brakes flat out work better....but they come with a few downsides (weight, complexity, noise when wet, frame and fork stiffness) and if the downsides outweigh the upside of better braking then it makes little sense to go discs in my opinion.

I hope that makes sense.

dave
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  #1067  
Old 07-06-2018, 10:29 AM
jamesdak jamesdak is offline
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Originally Posted by David Kirk View Post
The top of Forswall Road - one really needs to work for this view. It might be steep but at least it's slippery and windy.

dave

Beautiful bike and beautiful area. 2 more months until my annual pilgrimage to MT. Going to bike The Going To The Sun road this time since it may be my last annual trip to Glacier. It's getting too crowded.
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  #1068  
Old 07-06-2018, 11:33 AM
Clean39T Clean39T is offline
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Originally Posted by David Kirk View Post
That's a big question and I have trouble with a simple answer. I think both rim and disc brakes are great and that one isn't better than the other. That said I think certain brakes are better suited to a particular application.

I think if you want to use a tire that's too wide to fit under a brake caliper, you are riding in the slop, snow or rain consistently, you are riding in the high mountains with long steep descents while using carbon rims.....etc.....then disc brakes are probably the better choice.

If you are riding on flat or rolling terrain, in the dry, with tires that aren't super wide and your biggest braking concern is not hitting your garage door when you get home then rim brakes might be the best choice.

Each brake type is a compromise. Disc brakes flat out work better....but they come with a few downsides (weight, complexity, noise when wet, frame and fork stiffness) and if the downsides outweigh the upside of better braking then it makes little sense to go discs in my opinion.

I hope that makes sense.

dave
I seem to recall you also saying that disc brakes reduce your ability to tune ride characteristics since you have to stiffen things up at the fork legs and stays to handle the braking load and keep things balanced symmetrically...
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Last edited by Clean39T; 07-07-2018 at 02:30 PM.
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  #1069  
Old 07-06-2018, 12:26 PM
Climb01742 Climb01742 is offline
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Quote:
Originally Posted by David Kirk View Post
That's a big question and I have trouble with a simple answer. I think both rim and disc brakes are great and that one isn't better than the other. That said I think certain brakes are better suited to a particular application.

I think if you want to use a tire that's too wide to fit under a brake caliper, you are riding in the slop, snow or rain consistently, you are riding in the high mountains with long steep descents while using carbon rims.....etc.....then disc brakes are probably the better choice.

If you are riding on flat or rolling terrain, in the dry, with tires that aren't super wide and your biggest braking concern is not hitting your garage door when you get home then rim brakes might be the best choice.

Each brake type is a compromise. Disc brakes flat out work better....but they come with a few downsides (weight, complexity, noise when wet, frame and fork stiffness) and if the downsides outweigh the upside of better braking then it makes little sense to go discs in my opinion.

I hope that makes sense.

dave
It does make sense, Dave. Very. Thank you for answering.
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  #1070  
Old 07-06-2018, 12:44 PM
pncguy pncguy is offline
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Quote:
Originally Posted by David Kirk View Post
That's a big question and I have trouble with a simple answer. I think both rim and disc brakes are great and that one isn't better than the other. That said I think certain brakes are better suited to a particular application.

I think if you want to use a tire that's too wide to fit under a brake caliper, you are riding in the slop, snow or rain consistently, you are riding in the high mountains with long steep descents while using carbon rims.....etc.....then disc brakes are probably the better choice.

If you are riding on flat or rolling terrain, in the dry, with tires that aren't super wide and your biggest braking concern is not hitting your garage door when you get home then rim brakes might be the best choice.

Each brake type is a compromise. Disc brakes flat out work better....but they come with a few downsides (weight, complexity, noise when wet, frame and fork stiffness) and if the downsides outweigh the upside of better braking then it makes little sense to go discs in my opinion.

I hope that makes sense.

dave
That's the most concise answer I've seen yet. I'll add: if you want to put fenders on the bike, discs give you more options.
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  #1071  
Old 07-06-2018, 07:18 PM
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David Kirk David Kirk is offline
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My fraternal twins.....Onesto lugged and Onesto fillet.

dave

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  #1072  
Old 07-07-2018, 12:07 AM
tylercheung tylercheung is offline
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Originally Posted by Clean39T View Post
I seem to recall you also saying that disc brakes reduce your ability to tune ride characteristics since you have to stiffen things up at the fork legs and stays to handle the braking load and keep things balanced symmetrically...

Do I get a gold star?
This is what I'm curious about. How much do they compromise ride quality/handling/frame elasticity on a disc vs. caliper road bike, say, for example, on a JKS model all other variables being equal? Is it very perceptible or more subtle? Could the disc frame be designed via other parameters to mitigate the engineering requirements for the added forces from discs?
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  #1073  
Old 07-07-2018, 11:13 AM
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David Kirk David Kirk is offline
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Originally Posted by tylercheung View Post
This is what I'm curious about. How much do they compromise ride quality/handling/frame elasticity on a disc vs. caliper road bike, say, for example, on a JKS model all other variables being equal? Is it very perceptible or more subtle? Could the disc frame be designed via other parameters to mitigate the engineering requirements for the added forces from discs?
I'm not sure I fully understand your question but I'll do my best to answer it and hopefully it will be in the ballpark.

With rim brakes the braking load is distributed and carried far from the center of wheel rotation and is generally carried by two fork blades in the front and two seat stays in the rear. The fork crown and rear brake bridge are far from the hub so the loads are pretty low and easy to deal with.

When we go to disc brakes this changes in a huge way. First the brake loads are imparted to the frame and fork very close to the center of rotation so the forces are much greater. Secondly the brake loads are carried by only one side of the fork or frame which is very asymmetric. This is a big deal both front and rear but the real challenge is the front. The brake loads being put on just one blade and low on that blade mean that the blade needs to be a good bit stiffer and stronger to deal with it well. This means that the fork needs to be substantially stiffer and heavier to work with discs properly. The downsides to this should be obvious - the fork is heavier than it would otherwise be and the stiffness is greater than it would need to be otherwise. So weight and ride both suffer.

The same thing happens in the rear....the brake side chain stay (and maybe seat stay depending on brake type) needs to be heavier and stiffer. The rear end being a closed triangle helps but does not eliminate the issues.

So in the end....all things being equal....a disc frame and fork need to be stiffer and heavier to work properly. Will everyone notice it? No...I doubt they would. I sometimes ride with guys who will not notice that their tire is nearly flat let alone how stiff the fork is....but for some it will be a real downside and something that can be felt.

I've typed a lot of words....I hope some of them address your question!

dave
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  #1074  
Old 07-07-2018, 01:04 PM
hollowgram5 hollowgram5 is offline
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What a beautiful pair of bikes.. (They're also my size since I know they are Dan's! )

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My fraternal twins.....Onesto lugged and Onesto fillet.

dave

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  #1075  
Old 07-07-2018, 02:31 PM
Clean39T Clean39T is offline
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Originally Posted by David Kirk View Post
I'm not sure I fully understand your question but I'll do my best to answer it and hopefully it will be in the ballpark.

With rim brakes the braking load is distributed and carried far from the center of wheel rotation and is generally carried by two fork blades in the front and two seat stays in the rear. The fork crown and rear brake bridge are far from the hub so the loads are pretty low and easy to deal with.

When we go to disc brakes this changes in a huge way. First the brake loads are imparted to the frame and fork very close to the center of rotation so the forces are much greater. Secondly the brake loads are carried by only one side of the fork or frame which is very asymmetric. This is a big deal both front and rear but the real challenge is the front. The brake loads being put on just one blade and low on that blade mean that the blade needs to be a good bit stiffer and stronger to deal with it well. This means that the fork needs to be substantially stiffer and heavier to work with discs properly. The downsides to this should be obvious - the fork is heavier than it would otherwise be and the stiffness is greater than it would need to be otherwise. So weight and ride both suffer.

The same thing happens in the rear....the brake side chain stay (and maybe seat stay depending on brake type) needs to be heavier and stiffer. The rear end being a closed triangle helps but does not eliminate the issues.

So in the end....all things being equal....a disc frame and fork need to be stiffer and heavier to work properly. Will everyone notice it? No...I doubt they would. I sometimes ride with guys who will not notice that their tire is nearly flat let alone how stiff the fork is....but for some it will be a real downside and something that can be felt.

I've typed a lot of words....I hope some of them address your question!

dave
My recall wasn't too far off, but that explanation definitely makes much more sense...thanks!
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  #1076  
Old 07-10-2018, 01:35 PM
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David Kirk David Kirk is offline
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Stainless tubes and silver fillets on the Onesto Fillet.

dave

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  #1077  
Old 07-18-2018, 01:54 PM
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David Kirk David Kirk is offline
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Gothic fillets covered with Dario Pegoretti's finest.

dave

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  #1078  
Old 07-19-2018, 12:30 PM
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David Kirk David Kirk is offline
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Studio shot of the latest Gothic Fillet frameset and matching stem with paint by my friend Dario Pegoretti.

dave

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  #1079  
Old 07-19-2018, 06:00 PM
OtayBW OtayBW is offline
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Geez man. That is a WINNER!
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  #1080  
Old 07-20-2018, 03:32 PM
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David Kirk David Kirk is offline
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A pano shot of the World Headquarters just in time to shut down for the weekend. Time for a ride.

dave

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