Science behind the spokes - Bicycle wheel
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- Опубликовано: 7 авг 2024
- Why are bicycle wheels made using spokes, and why are they laced the way they are?
Do disc brakes put more load on the spokes?
Good and poor wheel designs.
CONTENTS:
00:00:00 Introduction - hub holding the rim
00:03:40 Spokes vs rods
00:06:59 Radial stiffness
00:08:39 Lateral stiffness
00:13:54 Radial lacing downsides
00:19:13 Cross lacing pattern
00:23:04 Trailing and leading spokes
00:26:00 Pre-tentioned structure
00:27:54 Vertical load
00:36:38 Rim brake loads
00:42:52 Disc brake loads
00:51:08 Why paired spokes suck
00:55:27 Very few spoke wheels
01:02:04 Spokes come in 4-s
Useful LINKS:
If you have any questions, please use the BikeGremlin forum (I try to respond to every comment, but RUclips sucks at notifications, especially when it comes to any follow-up questions):
www.bikegremlin.net/
Bicycle wheel building basics explained:
bike.bikegremlin.com/9276/bic...
Counter-steering explained:
bike.bikegremlin.com/2530/cou...
Jobst Brandt - The Bicycle Wheel (Amazon affiliate link):
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GremlinTube - a complete list of videos, sorted by categories:
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id: 1101 
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A good article on a related/same topic, written by Elvin Sullivan, and updated by Timmi Sinamowsk (thanks to Timm Sima for pointing it) - re-published with my comments:
bike.bikegremlin.com/14304/spoke-lacing-comparison-using-software/
If you have any questions, please use the BikeGremlin forum (I try to respond to every comment, but RUclips sucks at notifications, especially when it comes to any follow-up questions):
www.bikegremlin.net/
Relja
You know you’ve become a nerd when an hour long video about spokes is exciting!
Or old and friendless?
@@pentiuman how dare you call me out like that… lol… friends come and go no matter how much you take care of them, unlike a bike!
Grateful to be back here. As usual, you contextualize bikes within physics, engineering and logic.
I'm trying to get a decent Go-pro camera, so I can also capture some passion and riding techniques. :)
@@BikeGremlinUS Wow. That would be something. Looking forward
Great explanation!
I've always wondered how spoked wheels can withstand all sorts of forces that occur while riding.
Thanks a lot for this video.
Awesome science explained for the bicycles... Thanks for the effort.
THANK YOU. I have had questions for 25 years that were answered here. A friend compared a car wheel with bicycle wheel and said they are the same. Solid steel like the old cart wheel with steel in compression. Tesion and thin diameters change the conversation. I didn't understand his reasoning, however he is an engineer, and I couldn't explain why I disagreed. Thank you again.
Glad it helped. :)
Fun fact:
Automobile wheels used to be made with spokes - and one of the problems was making the wheels strong enough to take huge lateral loads that automobile wheels are stressed with (because the cars don't lean into corners). They used pretty wide hubs to get good bracing angles, drilled spoke holes in two "lines" on the rims, and cross-laced spokes (so the left flange spokes would go to the right line of rim holes) in order to achieve better bracing angles for handling big lateral loads.
Relja
Interesting information, many thanks for the video!
Hello. I had no idea you had a youtube channel. I've stumbled upon your web page a few times when going deep into some bicycle mechanics topics. The level of detailed information you provide is very high, up there with Sheldon Brown and RJ the Bike Guy. Thanks for sharing your knowledge! :)
Hi Carlos,
Thanks. Glad you like it. :)
I don't advertise the RUclips channel on the website much - I just embed videos once I've made a video demo of a certain topic (unless I forget :) ).
I have watched it all. thank you for your work 👍
You're welcome. Was it explained clearly enough (I am still struggling with English a bit :) )?
@@BikeGremlinUS Yeah! it was clear
thank you for your effort and explanation!
This is very good. Thanks.
Wow, cool. That is a quite clear explanation about working forces on a tension wheel.
I was experimenting with 3x/2x (drive side/ non-drive side) lacing pattern for rear wheel before and not really happy with the result. After an accident, the wheel was hard to get trued, and easily out of shape. Conversely, front wheel that actually crashing is still perfectly fine and true. I was using 2x/2x symmetrical lacing with trailing spokes inside the hubs for the front wheel.
Right now I'm attempting to rebuild that rear wheelset. Thanks to your article about simulation of lacing pattern, this time I would using 3x lacing pattern for both side. But I'm not really sure which side of hub (inside/outside) to place trailing and leading spokes. Will it better if laced symmetrical/ asymmetrical? Any insight about this particular topic woild be awesome.
Based on my practical experience and theoretical knowledge, the inside/outside arrangement is not really important and doesn't make any measurable difference. Whatever you find to look nicer or easier to lace will be fine.
Wonderful video- thank you!!! Very well explained, youre a great teacher.
Im still confused on the load that spokes take from our weight. Is it misunderstanding to think of the spoke directly above the hub to be "holding" the hub up? When there is force downwards onto the hub (say from the riders weight) does the tension on that top spoke go up?
Thanks. :)
Hubs hanging from the top spokes is a common misconception. The spokes on top get no measurable increase in tension as the wheel is loaded by the rider's weight. The spoke(s) at the bottom decrease in tension (i.e. loose some of the tension, not all) and that decreased pull on the rim by the bottom spoke(s) is what negates the load's force. It effectively "pushes back" by decreasing in tension, within a pre-tensioned structure.
In other words, a spoked wheel is a pre-tensioned structure, so it can be counter-intuitive, but that is how it works and transfers the loads.
@@BikeGremlinUS Thanks! I think Im beginning to wrap my head around it 😅I think i imagine the hub settling down lower when the rider gets on the bike- so then I think the top spoke must increase in tension (if the rim stays constant). But im realizing that doesnt necessarily happen. Thanks again for the video.
When I wrote about this on the forums of Ukraine and Russia, they laugh at me.
High quality spokes are now approved.
I have a 622 mm touring with 70 spokes on the rear wheel)))
There are no problems with the rim and spokes at all.
Even the loss of a few spokes does not result in rim wear.
48 spokes are enough, but 36 are not enough - if one is lost, there may already be a beating.
In my experience, with high quality rims and spokes, 40 is enough for touring.
Even if one spoke breaks, the wheel stays reasonably true.
48 gives diminishing returns, but with poor quality spokes, or loaded tandem bikes, it can make a difference.
But 70 spokes on obe wheel is something I’ve never seen - not even on motorcycles. :)
Which hubs and rims did you use?
@@BikeGremlinUS Homemade flanges made of duralumin.
Rim 36 spokes + 34 holes.
70 is a lot.
Now I plan to buy 622x48 wheels for tandem.
Rivet flanges on the sleeve.
@@BikeGremlinUS In 1992, I saw a formula for calculating the load on a spoke.
With an increase in the spokes by 2 times, the load is 4 times less.
The first wheel with 70 spokes was assembled in 1989.
In total, friends collected about 15 of these wheels.
if spokes are made of bad steel, it can be 100 spokes and it will break, 32 good quality spokes, good rim for single bike, road/mtb, and no problems, if tandem , 36 spokes should be ok if drivers are not fat
Hey man, I'm just curious what's your opinion on carbon spokes (crossed from every side) with 20 spoke count, are they any good?
Unless a sponsor insists on me riding such wheels, I'd definitely not go out of my way to buy them (or build wheels with carbon spokes - or with so few spokes regardless of their material).
My priorities are durability, robustness, serviceability and the ease of "limping" back home in case of a crash or similar.
whatr is left vs right spoke?
Tension left (for the left hand side spokes) vs Tension right.
Relja
What are your thoughts on 24 spokes rear spokes for 66 kg rider on sapim spokes..
If the bike is used for racing, it makes sense to use fewer spokes, and to use the aero spokes (like Sapim CX-RAY).
Rims that are not shallow also help with aerodynamics, and they are usually pretty strong and stiff, so that will help distribute any loads over as many spokes as possible.
For training or recreational riding on the other hand, I see no reason to go with fewer than 36 spokes.
Relja
@@BikeGremlinUS I started my journey with 36 spokes. Never complained about my setup being an endurance rider. Now I have shifted my focus to sprint cycling only. That has caused drastic changes to my bike. 24 spokes rear wheel with sapim double butted spokes should be ok for me on a DT Swiss 460 rim or risk off too much tension?
Secondly you pointed out that less number of spokes would need more tension. That makes sense but any Dr Swiss rim I check..whether it has 24 spokes or 32. The max tension on every rim is same 110. So not sure how to adjust my wheel tension going down on number of spokes
For rims, there are two limits:
1) How much total spoke tension a rim can take (max. total tension). This is affected by rim's strength and stiffness.
2) How much tension on one spoke a rim can take. This depends on how strong the nipple-to-rim interface is.
Yes, fewer spokes at the same tension will make for a weaker wheel. But you can't always compensate enough for having fewer spokes with more individual spoke tension because of the point 2.
So, with 24 spokes, you can go with the max. allowed tension for the drive-side rear spokes, and tension the NDS spokes as much as needed to keep the rim centred. For the front wheel, there's no reason to go over 100 kgf for either side (unless it's a disc brake wheel, in that case, you might go to 110 on the NDS, if that is required to keep the rim centred with the DS spokes having at least 70 kgf tension).
Having said that, with swagged spokes by either DT Swiss or Sapim, I would not worry about spokes breaking, even on a 24-spoke wheel (especially for riders who are not very heavy).
Edit:
WIth swagged spokes, it also makes sense to not go to the max tension limit, as they elongate more, and more easily, so a lot less risk of lower-tensioned spokes going slack. They also wind up more during truing (that must be accounted for when building, to make sure they are unwinded). Hence, it would probably be fine, if not better, to go with up to 105 or even 100 kgf max tension (if the rim's stated maximum is 110). Leaving a safety margin, without the risk of spokes going slack.
Relja
@@BikeGremlinUS thanks for the detailed response. My wheel rim say max tension 110 kg. Is that per spoke or for the entire rim please
If I knew the brand and the model, I might be able to answer that - by googling the manufacturer's specifications for the rim.
Come on! Never apologize for your poor English! If one complies, just ask how many languages one speaks. Explaining with simple words the basics of the physical processes of the laced wheels is a great job. Keep doing it.
Thanks. :)
Numerous people have commented that they can understand me clearly and easily. I'm very happy to hear that.
Just as importantly, no one complained about not being able to understand me.
My logic (thinking) is:
The goal is to relay the information clearly.
If native speakers can't understand, then non-native speakers might have even more problems understanding.
So it doesn't matter if anyone complaining knows any other language. It would still mean that my message is not clearly conveyed.
Fortunately, based on all the feedback, there's no problem. :)
Having said that, when I do a video in my native, on the same topic, I'm able to speak more fluently and convey more info with fewer words = a lot shorter video.
That's why I'm always working on improving my written and spoken English. Writing articles and recording videos is a great way to do that. :)
jel imaš taj video i na srpski, teško mi se koncetrirati
RUclips pretraga nije baš sjajna, tako da sam napravio spisak svih objavljenih videa na srpskom:
bicikl.bikegremlin.com/youtube/
I na engleskom:
bike.bikegremlin.com/youtube/
Ovde je taj video:
ruclips.net/video/F9eMt70PM50/видео.html
Gotta say this is a very long-winded explanation on how you got dropped on your group ride.
hehehehh :)