FAQ: Which Wheels for Bigger Riders?
QUESTION:
Looking for a wheelset for my Cervelo. I am 6'5 and weigh 225.
Thanks,
John B.
ANSWER:
Hi John,
Thanks for your inquiry!
The most suitable road wheelset for a bigger rider like you would be the OCTTO Cyclocross Racing Tubular Wheels.
Now don't be put off by the Cyclocross designation. These are exactly the same as the OCTTO Road Racing 50mm deep Wheels, except that the 'cross version use a round butted spoke instead of a Aerolite bladed and superlight spoke. In cyclocross, the benefits of bladed spokes are less useful, so we can offer the 'cross version a bit more economically.
However, the other benefit of the round spoke is that it's about 32% stiffer. For a larger rider, this wheel is stiffer laterally than our regular race version. How much stiffer is this? If we kept the lighter bladed spokes, then to gain the same stiffness we would have to increase the spoke count from 20/24 to 26/32 (front/rear, respectively)! (And we'd have to raise the price to account for all the extra and relatively costly bladed spokes.)
The 50mm deep rim has an aerodynamic benefit on the road and a mud-shedding benefit in 'cross but it's extra depth also makes it inherently stronger and laterally stiffer than a shallower rim and therefore more suitable for a larger rider.
The OCTTO 50mm rim, in particular, is pretty bomb-proof. We have some Team-used wheels that currently in their fourth year of Elite road and cross racing on the same rims. Typical Aluminum rims (even our own excellent AL rims), eventually will either wear out at the brake-tracks from galling, or suffer fatigue cracks around the spoke holes; these are due to inherent material-properties of AL. The OCTTO carbon rims wear very little at the brake-tracks (the carbon is harder than the brake pads) and carbon-composites are inherently fatigue resistant.
Tubular tires are inherently pinch-flat resistant, so for a bigger rider that's one big benefit over clinchers.
Another benefit is that tubular rims allow much higher tire inflation pressure over clinchers. A bigger rider needs much higher tire pressure. Schwalbe tire has a good explanation on their website.
For an "average" 75kg (165lb) rider on a 23mm tire, the suggested tire pressure is 115 psi. For every kg over that, the tire pressure should go up 1%. Therefore for a 225lb (102kg) rider, the suggested tire pressure should be 146lbs.
Most clincher tires and rims cannot handle that kind of pressure and/or risk blowing the tire off the rim; tubular tires and rims can handle that kind of pressure and the higher the pressure, the better that the tire stays on the rim.
Further, depending on the model of Cervélo frame and fork you may be able to go to a larger 25mm tire. Most of the R-series (R3, R5, etc) have clearance for them. The bigger tire provides a bit more "vertical travel" for a bigger rider and so can reduce tire pressure a bit.
One nice feature of the OCTTO 50mm rim is that it actually works well with bigger 23mm-and-larger tires. Some other 50mm rims are designed around narrower 20-to-22mm tubulars and the larger tires don't seat as well on them.
(Aside: if you are concerned about the practicality changing flats on tubulars...let's compare them to clinchers. First of all, tubulars have the aforementioned benefit of being pinch-flat resistant, the most common type of flat. Punctures are less common and can be mitigated by tire-sealants such as Caffe Latex or Stan's NoTubes. When changing a puncture on the road, it's actually less complicated and faster than changing clincher. With a clincher you can fail to find and remove whatever caused the flat (glass, wire, etc) or you can pinch the tube when re-installing it either by the tire lever or between the tire-bed and the rim...these situations will lead to a second flat. With a tubular, the tire is changed together with the tube and it's impossible to pinch flat it when re-installing.)
Now, those are just the purely functional benefits of these wheels for a larger rider. But, there are two more coincidental side-benefits. First, there are aerodynamic benefits of the deep 50mm rim combined with the low spoke count. The second is that weight of the wheelset is only 1390g, which is still pretty light (even for a lighter rider).
So, in summary, while carbon tubulars are a bit more expensive than AL wheels, they are a fair value for a stiff, strong, durable, aero and lightweight wheelset.
Regards,
Dr. Octto
Hi John,
Thanks for your inquiry!
The most suitable road wheelset for a bigger rider like you would be the OCTTO Cyclocross Racing Tubular Wheels.
Now don't be put off by the Cyclocross designation. These are exactly the same as the OCTTO Road Racing 50mm deep Wheels, except that the 'cross version use a round butted spoke instead of a Aerolite bladed and superlight spoke. In cyclocross, the benefits of bladed spokes are less useful, so we can offer the 'cross version a bit more economically.
However, the other benefit of the round spoke is that it's about 32% stiffer. For a larger rider, this wheel is stiffer laterally than our regular race version. How much stiffer is this? If we kept the lighter bladed spokes, then to gain the same stiffness we would have to increase the spoke count from 20/24 to 26/32 (front/rear, respectively)! (And we'd have to raise the price to account for all the extra and relatively costly bladed spokes.)
The 50mm deep rim has an aerodynamic benefit on the road and a mud-shedding benefit in 'cross but it's extra depth also makes it inherently stronger and laterally stiffer than a shallower rim and therefore more suitable for a larger rider.
The OCTTO 50mm rim, in particular, is pretty bomb-proof. We have some Team-used wheels that currently in their fourth year of Elite road and cross racing on the same rims. Typical Aluminum rims (even our own excellent AL rims), eventually will either wear out at the brake-tracks from galling, or suffer fatigue cracks around the spoke holes; these are due to inherent material-properties of AL. The OCTTO carbon rims wear very little at the brake-tracks (the carbon is harder than the brake pads) and carbon-composites are inherently fatigue resistant.
Tubular tires are inherently pinch-flat resistant, so for a bigger rider that's one big benefit over clinchers.
Another benefit is that tubular rims allow much higher tire inflation pressure over clinchers. A bigger rider needs much higher tire pressure. Schwalbe tire has a good explanation on their website.
For an "average" 75kg (165lb) rider on a 23mm tire, the suggested tire pressure is 115 psi. For every kg over that, the tire pressure should go up 1%. Therefore for a 225lb (102kg) rider, the suggested tire pressure should be 146lbs.
Most clincher tires and rims cannot handle that kind of pressure and/or risk blowing the tire off the rim; tubular tires and rims can handle that kind of pressure and the higher the pressure, the better that the tire stays on the rim.
Further, depending on the model of Cervélo frame and fork you may be able to go to a larger 25mm tire. Most of the R-series (R3, R5, etc) have clearance for them. The bigger tire provides a bit more "vertical travel" for a bigger rider and so can reduce tire pressure a bit.
One nice feature of the OCTTO 50mm rim is that it actually works well with bigger 23mm-and-larger tires. Some other 50mm rims are designed around narrower 20-to-22mm tubulars and the larger tires don't seat as well on them.
(Aside: if you are concerned about the practicality changing flats on tubulars...let's compare them to clinchers. First of all, tubulars have the aforementioned benefit of being pinch-flat resistant, the most common type of flat. Punctures are less common and can be mitigated by tire-sealants such as Caffe Latex or Stan's NoTubes. When changing a puncture on the road, it's actually less complicated and faster than changing clincher. With a clincher you can fail to find and remove whatever caused the flat (glass, wire, etc) or you can pinch the tube when re-installing it either by the tire lever or between the tire-bed and the rim...these situations will lead to a second flat. With a tubular, the tire is changed together with the tube and it's impossible to pinch flat it when re-installing.)
Now, those are just the purely functional benefits of these wheels for a larger rider. But, there are two more coincidental side-benefits. First, there are aerodynamic benefits of the deep 50mm rim combined with the low spoke count. The second is that weight of the wheelset is only 1390g, which is still pretty light (even for a lighter rider).
So, in summary, while carbon tubulars are a bit more expensive than AL wheels, they are a fair value for a stiff, strong, durable, aero and lightweight wheelset.
Regards,
Dr. Octto