Author Topic: Thorn Nomad Mk2 disc brakes  (Read 7488 times)

PH

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Re: Thorn Nomad Mk2 disc brakes
« Reply #30 on: August 09, 2022, 03:32:49 pm »
I now have two bikes with QR front disc forks, I'm confident about riding them, I do take extra care to ensure they're tightly fitted.  No disc brake will eject a well fitted wheel, the issue is that it can unwind the skewer and once it's started to do so it rapidly continues to the point where its no longer well fitted and can easily be ejected.
it's one of those things where it's never likely to happen to you, that doesn't mean it can't. I prefer to use an alan key type skewer rather than a cam type, partly because I think it can be done up tighter, but mostly because you get a better feel for how tight it is. I frequently back the skewer off half a turn, enough to be sure the wheel is fully seated in the dropout, then re-tighten.  It's never needed doing and that's the danger, it makes it easy to be complacent about it.
« Last Edit: August 09, 2022, 03:37:02 pm by PH »

mickeg

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Re: Thorn Nomad Mk2 disc brakes
« Reply #31 on: August 09, 2022, 04:02:43 pm »
My one disc brake bike is only disc on rear.  I had a choice on that frame, through axle or quick release, I opted for quick release.  Very happy with it.

I have heard frequent complaints that people say they have trouble getting their disc brake aligned correctly after replacing the wheel with quick release, but that has never been a problem for me.  Perhaps the dropouts on their bikes had a bit more cut away for the axle than really necessary and had sloppy wheel tolerance in the dropouts?

I am hoping that I can stick with my current fleet of quick release bikes and not replace any, as I have no interest in through axle.  A friend of mine got a through axle, had trouble figuring it out, I tried to help him and I had a lot of difficulty getting it all aligned right to put the wheel in, where a quick release wheel would have dropped right in.

There are people that never learned that the quick release mechanism is a cam operated tightener, they thought the lever on it was a substitute for a wrench.  A gal I used to work with was smart, she was a scientist with a masters degree, and I was really shocked when I saw that she did not know how to operate a quick release.  I think that is part of the problem with quick releases was that user error was too common and too many bike shops never trained the buyers on the basics.
« Last Edit: August 09, 2022, 08:09:43 pm by mickeg »

CycleTourer

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Re: Thorn Nomad Mk2 disc brakes
« Reply #32 on: August 09, 2022, 06:50:05 pm »
My QR disc-fork has VERY deep lawyer-lugs, and as well as that the drop-out faces slightly forwards, so the reaction from the disc brake operation will not force it out of the drop-outs. I am very confident and happy about this design.

It’s normal for you personally to be confident and yes, any such accident would be a freak accident. But the fear of liability is widespread throughout the industry, so this determines many designers’ new bikes.

I once came across a website describing the original lawsuit (around 2010?) and the reactions to it by various companies over the following years. I lost the link, but it would be great if someone else had it.
« Last Edit: August 09, 2022, 06:51:50 pm by CycleTourer »

il padrone

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Re: Thorn Nomad Mk2 disc brakes
« Reply #33 on: August 10, 2022, 01:51:43 am »
My one disc brake bike is only disc on rear.  I had a choice on that frame, through axle or quick release, I opted for quick release.  Very happy with it.

I have heard frequent complaints that people say they have trouble getting their disc brake aligned correctly after replacing the wheel with quick release, but that has never been a problem for me.  Perhaps the dropouts on their bikes had a bit more cut away for the axle than really necessary and had sloppy wheel tolerance in the dropouts?

I think many such issues are all due to people touching the brake lever while the wheel is out, pushing the piston in a bit. I have found the alignment and refitting of the Rohloff rear (with disc, EX-box and chain) to be tricky, but happily I only very rarely have that off the bike.

I am hoping that I can stick with my current fleet of quick release bikes and not replace any, as I have no interest in through axle.  A friend of mine got a through axle, had trouble figuring it out, I tried to help him and I had a lot of difficulty getting it all aligned right to put the wheel in, where a quick release wheel would have dropped right in.

There are people that never learned that the quick release mechanism is a cam operated tightener, they thought the lever on it was a substitute for a wrench.  A gal I used to work with was smart, she was a scientist with a masters degree, and I was really shocked when I saw that she did not know how to operate a quick release.  I think that is part of the problem with quick releases was that user error was too common and too many bike shops never trained the buyers on the basics.

I have noticed this as well, often among people that I would have thought had more intelligence.

GamblerGORD649

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Re: Thorn Nomad Mk2 disc brakes
« Reply #34 on: August 10, 2022, 06:02:52 am »
 ::) OR you can get a bolt on SA XL-FDD dyno drum brake. Set and forget for 30,000+ miles, with maybe a bearing change.  Any disc fork will be strong enough for it.
My first one is on it's 3rd bike, getting real close to 30,000. I rode it 127.5 rolly miles last Saturday, with the SA XL-RD5w.
2 weeks ago I got it up to 40 mph down a hill, hit the brakes and stopped in 40 feet I guess. Zero drama. NO wheel is easier to dismount and mount.

GamblerGORD649

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Re: Thorn Nomad Mk2 disc brakes
« Reply #35 on: August 10, 2022, 05:56:04 pm »
I got it up to 40 mph down a hill, hit the brakes and stopped in 40 feet I guess.
Nice story. When is the movie coming out?

40mph is not 80kmh, but not far off it.
"So with a velocity of 80 km/p/h, on a 15% gradient downwards, with a Bicycle Brake Reaction Time of 2.5 seconds, a Bicycle Brake Response Time of  22.68 seconds and a 0.25 Coefficient Of Friction, the shortest possible Distance to Brake to Stop (without skidding) is 55.56 + 251.95 = 307.51 metres"
https://www.muggaccinos.com/Liability/BrakeCalcs/Braking_formula/TwoDistanceToBrakeToStopFormulae.htm

WTF are you and that looney website talking about??? LOL hahaha >>1000 feet to stop??? LOL hahahahahahahahaha
 I used BOTH drum brakes. The road was FLAT when I braked. Reaction time has zero to do with my stopping. Anyway, .25 sec is more like it. Lots of times I stopped from 35 mph to take a photo on a hill on tour at 290 lbs total. I doubt it was more than 120 feet.
But I was on a really steep hill in North Vancouver with about 8 blocks to the bottom. This was when I had a POOR caliper on my Rohloff. So I did a release/ stop every 6 feet. But it worked and this was on the sidewalk. It also worked so well in Vietnam/ China, it broke my weak fork 3 times in the same place near the top.
I don't need anywhere near 15% to get my SA 5w to 46 mph either. Not even rod brakes are that bad. LOL.
« Last Edit: August 11, 2022, 06:06:02 am by GamblerGORD649 »

mickeg

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Re: Thorn Nomad Mk2 disc brakes
« Reply #36 on: August 10, 2022, 07:44:51 pm »
...
2 weeks ago I got it up to 40 mph down a hill, hit the brakes and stopped in 40 feet I guess. ...

I doubt that a bicyclist could physically do that without flying over the handlebars, center of gravity too high.  Especially on a downhill where their center of gravity is shifted more forward on the bike.  I suspect a F1 race car might be able to do it.

I went over the handlebars a couple years ago, not fun.  Trying to make it to the intersection before the light turned red, and a moron in a car to my left decided to pass me before they turned right.  Pulled up next to me and tried to make a right turn without getting past me first.  Ribs hurt for weeks after that.  I was surprised no dents in my titanium frame.  And I was well below 40 mph.

Moronic

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Re: Thorn Nomad Mk2 disc brakes
« Reply #37 on: August 11, 2022, 05:23:21 am »
Forty mph is 59 feet per second.

It's implausible that Gambler was stationary less than a second after applying the brake at 40mph. OTOH it is not implausible that he stopped with, as he says, zero drama. And that is the more emphatic claim (he qualified with 40ft with an 'I guess'), even if it is also the less consequential claim.

Just about any brake can stop a cyclist from 40mph with no drama. The drama arises only when there's a reason to stop in  a hurry.

Edit: a bit more research suggests your ordinary motor car can stop from 37mph in 65ft from the point where the brake was applied (that is, excluding reaction time).

https://www.qld.gov.au/transport/safety/road-safety/driving-safely/stopping-distances/graph

So, "I guess" 40 ft is a pretty good guess if a bicycle with a good brake and tyre stops as well as a car. And only a 300 per cent under-estimation if it stops half as well.
« Last Edit: August 11, 2022, 05:39:41 am by Moronic »
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GamblerGORD649

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Re: Thorn Nomad Mk2 disc brakes
« Reply #38 on: August 11, 2022, 06:40:21 am »
https://www.google.ca/maps/@53.5321972,-113.5374236,123m/data=!3m1!1e3?hl=en

Here is the short hill (off to the right to 116 street) and bridge at the bottom. Total 550 m.
I was going full speed about where the dark red car is, 400 m along. Here I had to hesitate as a car was wanting to cross between the islands. So I coasted another 130 where I decided to make a full stop from 38 mph, about where the center of Groat Road is. So that leaves 20 m at most.
I rode up the side path twice that day as this area was in the pro triathlon race course for 2 days.
« Last Edit: August 11, 2022, 04:18:29 pm by GamblerGORD649 »

JohnR

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Re: Thorn Nomad Mk2 disc brakes
« Reply #39 on: August 11, 2022, 11:55:50 am »
Here's someone occasionally managing to stop in 40ft https://www.youtube.com/watch?v=FJe99BjV8bM but he wasn't starting from 40mph. Kinetic energy is proportional to speed squared so stopping from 40mph takes four times the braking effort of stopping from 20mph.

GamblerGORD649

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Re: Thorn Nomad Mk2 disc brakes
« Reply #40 on: August 13, 2022, 07:58:12 am »
 I said I got UP to 40 mph ON the hill.
Sorry I didn't say in the first post I stopped on the FLAT after the bottom, but I did in the second one.
But anyway, I redid the test today with only me there, 39.9 mph. I stopped DEAD with NO skidding, in 6 or 7 turns of the 700 x 36c tires. It was 1 second past the bridge expansion plate.
So that is most likely between 42 and 46 feet. The lane is curving, so it was hard to pick a starting line going 58 fps. A spotter would sure help. I turned the bike around and counted the times the stem went around. It's set at 2170 mm -- edited. My front tire is a low miles but 9 year old Schwalbe Marathon, often specked on city bikes.

So it sure as hell isn't that LUDICROUS 1000 feet mentioned the post after mine. LOL. Even more NUTS is their assertion of 2.5 second "bicycle brake response" time. LOL hahahahahaha I could beat that from dead ASLEEP.
So let's see YOUR results from 40 mph. I bet there's ZERO chance any of you can do better. LOL.
=========
Oh and about that video clown stopping a MTB in 37 to 52 feet from 23 mph with hydro discs?? Is that how laughably HORRIBLE your brakes are?? LOL
And NO I don't fly over the bars. LOL.
« Last Edit: August 13, 2022, 08:28:09 pm by GamblerGORD649 »

PH

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Re: Thorn Nomad Mk2 disc brakes
« Reply #41 on: August 13, 2022, 11:08:32 am »
So let's see YOUR results from 40 mph. I bet there's ZERO chance any of you can do better. LOL.
I've stopped from about 20mph in less than 6", I have the photos, and scars, to prove it.
Quote
Oh and about that video clown stopping a MTB in 37 to 52 feet from 23 mph with hydro discs?? Is that how laughably HORRIBLE your brakes are?? LOL
That clearly demonstrated two things, first how variable the stopping distances with the same equipment was, which is the human element.  More importantly, that the first thing to restrict the stopping distance was the tyre's grip. 
Neither of those things surprise me, the only failed braking I've experienced has been the loss of control between tyre and surface.  I've had this with DP calipers and V's.  It wouldn't make any difference if you put a motorcycle four piston disc caliper on a huge rotor you still wouldn't stop in a shorter distance.  My experience with cable drum brakes is restricted to motorbikes, simple, easy, reliable, decent stopping, the only downside and the reason they're no longer as common, is the feel and modulation. That comes across in the above video as well, he's clearly impressed with the hydraulics for reasons other than the stopping distance, this is my opinion as well.
Well done for your incredible ability in stopping, very impressive, but it must be down to something other than the brakes.