alathIN

Nonsense. You specifically reacted to "the lightest possible wheelset," pointing out that nobody was advocating "lightest possible." You were taking the expression literally, or at least being an argumentative jerk on the basis of a literal reading of the phrase.

How about if I said "I have personally found it helpful to be willing to trade off weight in favor of durability?"
Would that please your majesty?

kafreeman

I ride on decently smooth roads, somtimes I find a pothole but they aren't that wide spread. I was 250 riding on the stock PR2 rim that came on the bike. I was looking at the wider and deeper cross section rims as they will have a higher stiffness than the thinner and shorter sections. I was interested in the Boyd Altamont but the Kinlin might be a better option.

I looked at the Ultegra 6800 but I see a lot of comments saying they arent sevicable. I was slightly concerned about the lower spoke count.

What advantages does an offset rim give over a standard profile? Does that allow for a closer balance in tension for each side of the hub?

prs1

I haven't had any problems with my stock shimano set yet. I'm ~220 and 6'1. Whats an OK weight for typical higher end lower spoke wheels / carbon wheels? I wanted to upgrade my wheels when I'm back in shape. But even in great shape im typically ~180-190.

rpenmanparker 

Yes the offset rim helps to balance side-to-side tension.

Tickstart

Exactly how enormous bike are we talking here?

colnago62

Carbon rimmed wheels are much stiffer than aluminum wheels.at your weight, you shouldn't have any problems.

kafreeman

I think it is about 21 lbs loaded.

rpenmanparker 

Carbon may be somewhat stiffer, but not so much at the same depth. The real stiffness of carbon wheels comes with the deep aero profiles.

kafreeman

Bike weighs in at 20.6 lbs.

kafreeman

I went with the Kinlin C31 and C31OC rim from BHS, SL85W and SL210 hub with Sapim Laser Spokes.

We'll see how it goes.

ColaJacket

For the OP, just out of curiosity, when you've busted a spoke or cracked a rim, had you recently bottomed out your tires onto the rims? You did say that you occassionally hit a pothole.

You might need to be careful on the size tire and tire pressure.

GH

chaadster

Spoke choice is curious. Why not, say, the aero profile CX, for added strength snd stiffness? Are you going to run tubeless?

rpenmanparker 

Re: stiffness, I understand your comment, but more about that later. Concerning strength, there is no significant difference. They both have 2.0 mm ends where most breakage occurs. Technically the CX spoke would be stronger than the Laser spoke in a tensile test, but simple tension is not what breaks most spokes. Based on tensile strength the Laser should be just as useful for heavy riders as the CX.

Then there is the question of elongation which would be about twice as much for the Laser as the CX at any normal spoke tension. That extra elongation protects the spoke against fatigue by helping it to not periodically go slack as the wheel rolls or suffers an impact. Since fatigue of the spoke ends are what usually lead to breakage, the Laser spoke should be much more durable than the CX.

And regarding stiffness, the 1.5 mm diameter provides more stiffness for the same amount of steel than a flatter shape would. In fact if you use the Park TM-1 chart as a guide, you will see a surprising fact. The 1.5mm round spoke is almost as stiff as a 2.6 X 1.4 mm bladed spoke. The CX isn't on the chart, but it is 2.8 X 1.3 mm, not too different from the 2.6 X 1.4 mm example on the chart. Take any deflection reading for the Laser spoke and compare it to the same deflection reading for the 2.6 X 1.4 aero spoke. The tensions for the two are nearly the same at the same deflections, less than 15% different at low readings and identical at the highest readings on the chart. That is because you are measuring and caring about stiffness in the direction where the aero spoke is most flexible. Basically its greatest stiffness is in the wrong direction. If I am not mistaken, the deflection caused by the Park meter spring at a given spoke tension is a valid measure of spoke stiffness. Especially since we are interested in spoke stiffness in the finished build, not when the spokes are not stressed. I am guessing that between the Laser and CX lateral stiffness is just about a wash. I wish I had better data to show this, but the Park meter chart is a pretty good approximation.

What I don't know is what CX spokes cost, but I'm hard pressed to see much advantage for the extra weight. Also a major problem is that the 2.8 mm width of the CX spokes means that special hub holes are required, either keyholed, slotted, or extra large diameter. that is very limiting to hub choice. If the modification is done after the OEM processing, it usually voids the hub warranty.

kafreeman

I may have on the cracked rim. I didnt find the crack, took it in for loose spokes and the shop found them. Not sure how long it had been cracked previous to that. The broken spoke, I had not flatted with that wheel.

Planning on a Conti S4000 II 25mm width.

CX-Rays are ~2.80, Lasers are $1. Trying to stay in the budget, and the rated tensile strength difference between them is small. Sapim rates the Laser at 1500 N/mm^2 and the CX-Ray at 1600 N/mm^2. According to the units these should be tensile strength, i.e. load applied for the cross section before fracture.

Looking at the cross sections....
Laser = pi*(1.5/2)^2 = 1.76 mm^2
CX-Ray = pi*(2.2*.9)/2 = 1.55 mm^2

Regarding stiffness and tension measurement... rpenmanparker is correct. Geometry determines stiffness. Determine where a neutral plane will be in the geometry and the further away material is from that the stiffer something should be. So the Park chart should be lower for the CX-Ray as it has a smaller cross section in the direction being measured. It does have a slightly higher rating in tension per unit area though. The Park tool does not directly measure tension, it measures deflection of an applied force for a length of material, and the chart with the tool provides what approximate tension the spoke will be at for a given deflection.

And unfortunately the C31W is only available in a max 28 spoke drilling, so that's what I'll be running. I should be able to get away with it with the rim's large cross section.

indyfabz

I am about 218 at my heaviest. Have had no issues with my Stan's tubeless. I think I have the Alpha 340 rims built (by a skilled builder) around CK hubs. Just get the shop to remove the unfortunate decals the wheels come with. The Alpha 400 Team has a max weight recommendation of 250 lbs:

Alpha 400 Team Wheelset

The max weight recommendation for the Alpha 340 Team is still within your range:

Alpha 340 Team Wheelset

rpenmanparker 

Sorry, but I have to correct my previous post. I was mistakenly talkkng about flexural stiffness which is not pertinent to the wheel stiffness discussion. Wheels depend on the tensile stiffness of spokes which would be anout half as much for Lasers as CXs. Lasers would be about the same as CX-Rays. I apologize for the confusion. So there would be an advantage to CXs in stiffness only if thst matters to you.

therhodeo

My good friend has 340's and hates them. Said they have almost no stiffness at all. He's maybe 165 after a big meal but puts down pretty good power.

chaadster

I was referring to CXs not CX Rays. Sapim says they are more rigid and stronger (i believe due to forge shaping). I do get the point about hub compatibility Rpenmanparker noted, though as someone who rides at your weight, I'd make the bub concession to get a more responsive wheel (theoretically; I don't know if the wheel in question would be less responsive or stiff, but would err on the side of the aero spoke, esp. for a conventional design, 28h hub).

Mr IGH

No engineering principal support this myth. In fact, quite the opposite, a thinner spoke flexes the wheel system more and will cause the wheel to go out of true more easily. It can be proven through simple superposition or by computer simulation and has been.

If you want/need a strong/stiffer wheel, go with 2.0 straight gauge over butted 2.0/1.8. It's the law!

rpenmanparker 

I would have to see the reports you allude to to judge the veracity of your claims. Many knowledgeable folks agree that greater elongation is desirable, but you are the first I have encountered who suggests the opposite. As for lighter spokes affecting the ability of a wheel to maintain true, I have neither heard of that nor experienced it myself. I'm open to accepting your claims, but only after being convinced by the facts you say are so simple to provide. May we expect those any time soon?

I am puzzled what you mean by a "thinner spoke flexes the system more". During actual use (riding) spokes don't cause the system to flex, applied outside forces do. In the vertical direction where the spokes are pulling in the same direction as the applied outside force, no spoke inhibits compression of the wheel. Laterally the spokes pulling opposite the direction of applied force will inhibit wheel flexing, and yes, thinner spokes won't do as good a job of keeping the wheel from flexing. What then is your point?

Mr IGH

Simplest method is "Superposition", a stiffer/stronger spoke makes a stiffer/stronger wheel, any freshman engineering student learns this in Statics class. I spoke with an mechanical engineer that does Finite Analysis for a local aerospace company, he did a computer simulation about 10 years ago and got the same results. Both of us presented our results to the oracle of this myth, Josbt B. he choose to attack our credentials instead of showing his results...Do you have any results? LOL.

Sorry, typo, I should have written, "A thinner spoke allows the wheel system to flex more...."

seymour1910

OP, I'm 6'1" and weigh 225. I own and have experience on the BOYD Rouleurs. I got them in 24/28 and have not had any issues with my wheels. They ride great and I'm happy I made the choice to go with them and not spend a lot more money. I think 1571g is just fine for the set. Keep them on your list. If you have questions, contact BOYD, he will answer anything questions or concerns and it doesn't take him days to get back to you either.

rpenmanparker 

Okay, stiffer, stronger wheel, but why more durable against stresses that don't exceed the strength characteristics of the wheel? You are segueing to that conclusion without connecting the dots.

If you presented the data to Brandt, surely you can present it to us.

Also twice you have thrown out the term "superposition" without saying what parameters you are superposing, as in time-temperature superposition.

Given Brandt's credentials and the lack of any data or write up backing up your theory, I'm gonna stick with him. You can persuade me, but not with anecdotes about folks doing calculations.

Jarrett2

Here you go:

Excel Sports - Custom Wheel Builder

Have fun with their wheel builder. You can swap out specs and dial in a set for you.

Turnaround and build quality are very good.

Jarrett2

Here's a lighter set for you:


Front Wheel

DT Swiss 350 Front Hub 28 Hole$51.21
Stans NoTubes ZTR Alpha 340 700c Rim 28 Hole $108.00
DT Swiss Revolution 14/17 Gauge Spokes Black $37.80
DT Swiss 14g Alloy Silver $7.28
3 Cross
Labor $25.00
Sub Total $229.29
Less Discount -$20.43
Total $208.86
Total Weight 618g

Rear Wheel

DT Swiss 350 11 Speed Rear Hub 32 Hole Shimano$160.11
Stans NoTubes ZTR Alpha 400 Rim 32 Hole 700c $94.00
DT Swiss Revolution 14/17 Gauge Spokes Black $21.60
DT Swiss Revolution 14/17 Gauge Spokes Black $21.60
DT Swiss 14g Alloy Silver $8.32
3 Cross
3 Cross
Labor $25.00
Sub Total $330.63
Less Discount -$30.56
Total $300.07
Total Weight 813g



Total Wheelset Weight: 1431g
Grand Total $508.93