Alloy wheels and flex?

[rowebr]

Let's assume these HED wheels are true and properly tensioned...If so, then I agree with the folks suggesting that re-building the wheel with slightly heavier/thicker spokes like the CX-Sprint may resolve the issue. Another spoke option would be the Pillar 1422 or 1423. I really like those, they aren't prone to twisting and are quite easy to build with.

It would be a neat experiment to see if that would do the trick, report back if you try it!

[ojingoh]

205-215 lb rider here. I can sprint well. WTB functioning Campy PM, btw.

I for one like a tiny bit of flex, it makes a less harsh wheel. In fact, you may be getting rub because you don't have enough flex.

I have a set of 28/28 HED Belgiums C2/King R45 and replaced the DS CX-Rays on the rear with CX-Sprints, really helped with uphill sprints.

My carbon 58mm wheels are 18/24 and quite stiff, even with Cx-Rays. I replaced the DS CX-Rays with CX-Sprints too, it's a slight difference, nothing as dramatic as it was with the HEDs.

If you are struggling with too much flex, I'd consider respoking just the DS with something heavier.

[Mark McM]

Originally Posted by ojingoh

If you are struggling with too much flex, I'd consider respoking just the DS with something heavier.

Thicker spokes on either side of the wheel will make the wheel stiffer, of course. But interestingly, since the NDS spokes have more bracing angle, they contribute more to the stiffness of the wheel. So the thickness of the NDS actually makes a bigger difference to wheel stiffness than the thickness of the DS spokes. In the end, the best bet to increase wheel stiffness is to use thicker spokes on both sides.

[Xrslug]

This has been really interesting, appreciate all the info — I know very little about wheel dynamics (beyond more spokes usually = stronger) and it’s showing. These are nearly new wheels, so it may make more sense to resell them rather than respoke but I do like the idea of experimenting with stiffer spokes, particularly because HED doesn’t sell these rims other than as complete wheels.

ETA: The heaviest successful pro rider I’m aware of is Magnus Backstedt who rode at 200ish pounds. Because he was riding in the era when not all wheels were carbon, I was curious to see what wheels he used. He rode Campagnolo Neutron wheels to win Paris-Roubaix and also rode Boras (although not at P-R). Not familiar with the Neutrons but I believe they are 20/24 spoke (presumably with pretty damn stiff spokes). Like a slightly higher-zoot Zonda?

[oldpotatoe]

Originally Posted by Xrslug

Thanks for the responses. In answer to questions, this is a steel frame, 1x oversize tubing (1 1/4 dt, 1 1/8 tt). Frame doesn’t feel noodley at all to me, but certainly has more flex than a carbon race frame. Spoke count is 20/24 Sapim CX Ray. Light-ish wheels but these are “all road” sturdy, wide wheels.
I didn’t open the calipers up completely but adjusted to give more room to the rim. When I sprint I do put out over 1,000 watts, but that’s not crazy power output for 190+ pounds. I have a feeling the answer is I need to lose 15 pounds . And also experiment with how much room I can leave between the pads and rim.

First, I'd check the tension of the wheels. CXRay are neat spokes but thin spokes none-the-less..Add a low spoke count, not surprised you may be rubbing the brake blocks.

I see not using CXRays on this low spoke count wheelset has been mentioned. When I build such a set I try to at least use CXSprints on drive side rear but CXSprints all around is not a bad idea...Or Using a mix of Sapim Lasers and Sapim Race or D-Light on drive side rear...then built properly with adequate and EVEN tension...The 'aero' benefits of these oval spokes, CXRay and CXSprints is really, really minor. Plus they are not cheap.

[El Chaba]

As a data point…..I built myself a set of wheels using PMP hubs, Sapim Cx-Ray spokes, 28 f/r, and Mavic Mach 2 rims. Now the rims are tubular and I would estimate that they are a bit lighter than the HED rims in question, but they are of a similar depth and profile. In use, they were fine for all types of riding situations, EXCEPT anytime that I would stand to climb or accelerate. I didn’t notice any brake rub, but I could feel the rear wheel flexing laterally. I rebuilt the rear wheel with standard round section DT 14/15 g spokes and the problem was solved. I am lighter than the OP by 30-35 lbs., so I don’t think that rider size alone is the issue. I think Cx-rays are great, but for use on the rear wheel they likely need a very deep and stiff rim.

[marciero]

Does anyone use straight gage spokes anymore?

[merckx]

Originally Posted by marciero

Does anyone use straight gage spokes anymore?

Specialized does on their OEM pre-builds.

[ridethecliche]

I'd say that rebuilding the wheels with thicker spokes is a waste of time, money, and effort. Just sell the wheels to a lighter rider and get them again in a 24/28 count.

But first, I'd just go through and retension them.

Is your fork steel as well? Is it rubbing in the front, the rear or both? Is the wheel true?

[benb]

195 is actually kind of gigantic for a lot of those weight weenie wheels, you've got to remember a lot of cyclists are 130-150lbs.

I have had the same issues before with similar spoke count wheels, I was usually in the 170-180lb range and my sprint was ~1000w or so.

I would have said I could feel the wheels annoyingly flexing at WAY less than sprint effort though.

More spokes for the win. I did get some help with those wheels with getting the tension just right and it mostly fixed the rubbing issues (a little flex seemingly was OK) but eventually those rims cracked between the nipples.

There have been others though (like Ksyrium SLs) that have 18/20 spokes that have never ever given me any noticeable flex or issues.

[thwart]

Originally Posted by Xrslug

ETA: The heaviest successful pro rider I’m aware of is Magnus Backstedt who rode at 200ish pounds. Because he was riding in the era when not all wheels were carbon, I was curious to see what wheels he used. He rode Campagnolo Neutron wheels to win Paris-Roubaix and also rode Boras (although not at P-R). Not familiar with the Neutrons but I believe they are 20/24 spoke (presumably with pretty damn stiff spokes). Like a slightly higher-zoot Zonda?

Interesting discussion here.

FWIW, the Neutrons are 22F/24R and have a somewhat lower profile rim than the Zonda. They appear to use Sapim CX-ray spokes or similar.

I own a tubular set… great wheels. Wasn’t aware of Backstedt’s riding them at P-R.

Gratuitous pic:

[Gummee]

Why big, powerful riders ride low spoke count wheels is a mystery. Not all wheels fit all people. ...as demonstrated by the OP

CX Rays are great spokes, but are thin and flexy. IIRC they're 15gs straight spokes flattened out. If you wouldn't ride 15gs spokes normally, you probably shouldn't ride CX Rays.

TL/DR: big, powerful guys need wheels for big, powerful guys

M

[Mark McM]

Originally Posted by Gummee

CX Rays are great spokes, but are thin and flexy. IIRC they're 15gs straight spokes flattened out. If you wouldn't ride 15gs spokes normally, you probably shouldn't ride CX Rays.

Firstly, using "gauge" numbers for spokes is archaic and imprecise. There are multiple wire gauge standards, so there is no one standard diameter for "15 gauge" spokes. A so-called "15 gauge" spoke may anywhere between 1.6mm and 1.8mm. Modern spoke manufacturers refer to their spokes in diameters/widths, not wire gauge.

In any case, CX-Ray spokes actually start at about 1.5mm in diameter (similar to Sapim X-Ray or DT Revolution spokes) before being flattened, so their weight and stiffness will be similar to other 1.5mm diameter spokes. CX-Sprint spokes start closer to 1.8mm before being flattened, so their weight and stiffness will be similar to other 1.8mm diameter spokes.

[ridethecliche]

Originally Posted by benb

195 is actually kind of gigantic for a lot of those weight weenie wheels, you've got to remember a lot of cyclists are 130-150lbs.

I have had the same issues before with similar spoke count wheels, I was usually in the 170-180lb range and my sprint was ~1000w or so.

I would have said I could feel the wheels annoyingly flexing at WAY less than sprint effort though.

More spokes for the win. I did get some help with those wheels with getting the tension just right and it mostly fixed the rubbing issues (a little flex seemingly was OK) but eventually those rims cracked between the nipples.

There have been others though (like Ksyrium SLs) that have 18/20 spokes that have never ever given me any noticeable flex or issues.

I used to sprint at like 1400W ish at 150ish lbs back in college. I haven't really had a ton of flex on wheels I used back in the day even with lower spoke counts. I think the average cyclist weighs atleast 150. Most spending money on this aren't 130lbs. Maybe in the race crew, but that's not the majority of riders.

Ksyriums had MASSIVE spokes. That's likely a big part of why they didn't flex. Those rims were also plenty stiff.

[Mark McM]

Originally Posted by ridethecliche

I used to sprint at like 1400W ish at 150ish lbs back in college. I haven't really had a ton of flex on wheels I used back in the day even with lower spoke counts. I think the average cyclist weighs atleast 150. Most spending money on this aren't 130lbs. Maybe in the race crew, but that's not the majority of riders.

Don't confuse power with force. Wheels flex under force, not power. Simply because of their extra weight a large rider can put more force on their bikes than a small rider - even if the large rider doesn't develop as much power as the small rider.