I ride a Cervelo P3 with a HED Disc wheel. I find that when I am really standing on it going up a steep hill the rear disc will flex so much that the tire rubs the chain stay. It only happens when I am letting the bike flop side to side as when I keep the centerline upright it does not happen.
Is this a function of the HED disc, all discs or what can you all offer?
Of course the obvious thing is to keep the bike upright which probably is the best use of effort anyway but just wondering. I already moved the set screws back a bit so I had more clearance between the disc and the seat tube fairing.
I really like the HED customer service, they are very responsive and you should call them directly…unfortunately I have had to use their customer service far too many times…not sure what gives but there seems to be lots of similar stories with their wheels. See multiple threads on here. There is a “float” in cassette where you can torque the cassettee by hand back and forth, which they say is normal, but I haven’t seen other wheels. They seem to be fine wheels, except that the same “loose” issue is written about a lot…
Obviously, if it is rubbing, then you have a problem and there is a good chance that the benefit of the disk will be offset by the inefficiency of the rub or the deflection, even if you set it up so that it doesn’t rub.
Here’s what I can offer. I ride a size 54 P3 with a 650c HED standard disc fitted with a 20mm tire. I have not observed the problem that you have discussed here. However, I only weigh 145 and tend to stay seated on hills. If you use a 700c wheel I suspect it may flex more because of its slightly longer radius. Also, the potential for frame contact will increase if you use a 23mm tire. Before you identify this as a genuine problem with the disc wheel, consider the construction and intended use of the disc and the config of the bike. Neither the wheel nor the bike were designed for climbing. Especially the kind of climbing that involves tossing the bike back and forth with maximum mashing force applied. I think you might be asking too much from the disc to remain on a linear plane in that situation. Bottom line (as you noted): save your oomph for the flats and down-hills where you can make some real time on this rig.
As usual, great advice from all. I weigh 174 and I should not be climbing and mashing on this rig. When I flex the wheel by hand it is amazing to me how much it will deflect with not that much pressure. But alas, I guess it was not designed for that type of stiffness. I will give HED a call anyway. Still love the product just a discovery.
yeah, I (and no one else on this forum it seems) has seen that back and forth flex on other wheels…but it is reported here somewhat often on HED’s…Not sure if that is a good thing…Certainly the guys who do a lot of wheels for the best TdF champ of all time would have their specs figured out, but I don’t understand how HED seems to be “different” than other wheels.
I’ve seen the same thing on my bike with 2 different Zipp discs and always just assumed it was the frame (Cervelo P2, so just like the P3, but older). So the consensus is that it is the wheel? huh…
Well, I have both brands (3’s and 909’s) and can’t bend my wheel or my cassette on the Z’s like I can on the H’s. There are multiple threads on this forum regarding that “feature” of the H’s and I haven’t ever seen it discussed for the Z’s. In fact one of the more recent threads had several people test both wheels and the consensus was that H had the issue and Z didn’t.
Lenticular discs tend to have a bit more lateral flex than flat type discs due to the construction methods and the nature of the wheel design. Damon Rinard’s old site has lots of independant data on all sorts of wheels, the newest of them are now 3-4 years old, but you can see that the differences are due more to construction methodology than brand with flat, honeycomb cored discs generally flexing about 2-2.5mm at the load specified while lens shaped discs typically flexed in the 4-5mm range at the same load…this is very consistent with our internal testing.
The other thing to remember is that this particular frame has just about the tightest rear wheel allowance of any on the market, which serves to really accentuate any wheel movement.
Bottom line I think we are saying is not to worry about it and just be aware of the limitations. That is why I paid $550 for my HED disc instead of $850+ for the Zipp?