Bicycle Mechanics - Spoke Count & Rider Weight

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View Full Version : Spoke Count & Rider Weight


rchan
01-21-03, 03:32 PM
Here's a question for the better informed. Since the advent of low spoke count wheels, I keep reading about weight limits associated with them. However, whenever I visit a manufacturer's site, I never see any recommended weight range given for their wheels. I've also never read any postings that explicitly mentioned actual numbers... I need quantitative data, please.

Is there a general rule or formula for weight and spoke count?

My current bike came with 24R/20F spoked wheels. Works fine, but occasionally when I make a quick correction at high speed, it doesn't feel as sure-footed as my previous 32R/32F wheels. So I am curious if I am bumping up on the recommended limit on these things.


D*Alex
01-21-03, 04:24 PM
Weight limits for a wheel with a certain number of spokes depends mostly on the gauge of the spoke, also the material that the spoke is made out of, as well as the type of spoke (straight, butted, bladed, swaged, etc.). Also, the pullout strength of the holes on the flange are a consideration, but these are usually higher than the failure strength of the spoke (unless, of course, you do something inadviseable, such as radially lace a high-flange hub...) Because of all these different concerns, it is d@mn hard to make any generalisation based solely on spoke count.

As far as manufacturers specs are concerned, yes, they all have maximum limits determined by the builder. Maybe you should e-mail the manufacturers that you are interested in.

John E
01-21-03, 08:03 PM
Sorry, I do not care for low spoke count wheels. Perhaps a racer can justify the reduced air drag/turbulence, but I want strong, reliable, light wheels, and basic physics tells us, "the higher the spoke count, the better the strength-to-weight ratio." Also, a rim with a high spoke count is amenable to accurate truing. I have 32-spoke wheels on the Bianchi and son #2's mountain bike, and 36-spoke wheels on everything else.



... proud to be a retrogrouch ...


rchan
01-22-03, 01:42 AM
What can I say? The bike came with them. I was surprised to find out that 20-24 spoke wheels aren't the rock bottom (still don't see how 16 spokes can hold a wheel together). In any case, if anything happens to these wheels, I'll probably go back to 32.

However, I have rode over more than a few hard bumps at high speeds, and they stayed true. So they're not as fragile as I first thought.

Zircon
01-22-03, 02:30 AM
I have been using Rolf Vector COMP wheels for the past year. I weigh about 70 kg(155 pounds) and have had absolutely no problem with them.

Both front and rear wheels have 18 flat spokes. I have been over a couple of harsh bumps with them and have not had to true them even once. Response wise they are perfect. I would really like to try the other wheels in the Rolf range.

wyobiker
01-22-03, 05:30 AM
I recently purchased a Raliegh Competition with the Shimano 540 wheels. These wheels have 16 bladed spokes front and rear. In researching any weight limitations for these in the spec/instruction sheets provided with the bike there is absolutely no mention of weight restriction. I guess my take on the weight issue would be that if there was an issue the manufacture would be liable at the very least be obligated to note such with the supplied paperwork. In lieu of of the silence in their supplied paperwork I beleive they are stating (indirectly) that there are NO such limitations. (IMHO)

My mountain bike has 32 spokes and quite frankly I can not tell any differerence in road feel/performance between the two. Obviously I don't take my road bike off the tarmac but having riddden both bikes on the same road route I normally utilize I beleive the comparsion is valid.

While I am not an engineer I don't necessarily subscribe to the "more is stronger" theory. I believe with the right mix of materials (metals) and design that you can accomplish the same, if not more, with less. (again IMHO)

roadbuzz
01-22-03, 10:37 AM
Can't answer your question, but had some comments. There are other things that affect feel & performance... it's not clear what you mean by "quick correction". The low spoke wheels are almost always radially spoked, some people complain about wind-up under hard acceleration.


Originally posted by rchan
I keep reading about weight limits associated with them. However, whenever I visit a manufacturer's site, I never see any recommended weight range given for their wheels.
Where are you reading about weight limits?

Seems to me that for weight limit information to be meaningful, it has to be surrounded with a bunch of other specs. Like maximum sprint torque, deepest pothole @ x velocity, etc.

slick1
01-22-03, 01:51 PM
i weigh about 85kg (187lb) and i have a set of shimano dura ace wheels on my bike. 16 flat spokes and have not had any problems whatsoever. the manufacturers claim that they are very stiff because of the spokes being anchored on the opposite side to where they are started from.

Eg. they are on the left hand side of the hub and they cross over to be anchored on the right hand side of the rim. i dont know how good their theory is but it better be good because i paid good money for them. eheheheh

slick1:D

rchan
01-22-03, 05:14 PM
Originally posted by roadbuzz
Can't answer your question, but had some comments. There are other things that affect feel & performance... it's not clear what you mean by "quick correction". The low spoke wheels are almost always radially spoked, some people complain about wind-up under hard acceleration.


Where are you reading about weight limits?

Seems to me that for weight limit information to be meaningful, it has to be surrounded with a bunch of other specs. Like maximum sprint torque, deepest pothole @ x velocity, etc.

Trying to describe what one 'feels' on a bike is much like people describing wine... 'astringent yet nutty' or something like that. I see a pothole at the last second and jerk a bit to avoid it; yeah, I shouldn't do that, but it gets dark in the winter. Doesn't feel the same as with my old wheels. I guess I don't have the proper vocabulary to tell you what I mean.

As to where I've read stuff about weight limits, I can't remember any 'official article', always some anecdotal comment about 'I'm only X lbs., so the wheels are fine, but might not be for a heavy rider.' Very vague qualitative statements, so I just wanted to know if there was something to it. Very little hard facts as far as I know.

roadbuzz
01-23-03, 10:53 AM
Originally posted by rchan
Trying to describe what one 'feels' on a bike is much like people describing wine... 'astringent yet nutty' or something like that. I see a pothole at the last second and jerk a bit to avoid it; yeah, I shouldn't do that, but it gets dark in the winter. Doesn't feel the same as with my old wheels. I guess I don't have the proper vocabulary to tell you what I mean.

Certainly sufficient. And besides, describing something like that borders on trying to describe the color blue. Low spoke count wheels generally compensate for fewer spokes with stiffer, stronger rims. So the usual complain is about a harsher ride. I don't doubt that they feel different and respond differently.


As to where I've read stuff about weight limits, I can't remember any 'official article', always some anecdotal comment about 'I'm only X lbs., so the wheels are fine, but might not be for a heavy rider.' Very vague qualitative statements, so I just wanted to know if there was something to it. Very little hard facts as far as I know.
The thought that was rattling around in the back of my head is anecdotal stuff from a friend of a friend who knew this quy who's related to Mick Jagger. The wheel tacoed, but they neglect to mention that it may have been damaged when they dropped it while removing it from the roof rack or something.
That said, I'm sure they have their limits, but unless you're a pretty hefty guy, they're probably okay. Quit worrying about your wheels, and find some better wine!

orguasch
01-23-03, 06:19 PM
I guess I will not have a problem with my wheels, I am using a Mavice Cosmic Elite, and I weight 165 lbs. Have looked at my wheels even when I have had a bad fall it is still very round and even.

Grendel
01-23-03, 09:03 PM
The only place I've found specs for rider weight limits is here (http://www.amclassic.com/PDF/Wheelset_Rider_Weight_Recommendations.pdf), but I suspect these limits are intended to apply only to their buildups and not a general guide.