advantage of deep section rims for slower riders

I weigh 80kg, bike weighs 9kg

I weigh 80kg, bike weighs 9kg. add in water and tools easily north of 90kg total weight

changing wheels to save 450g would be a massive wheel upgrade, but would only be 0.5% of total weight

Aero wheels can easily gain 1km/h on the flat, so 31kmh instead of 30kmh will save about 2 minutes over an hour ride.

lightweight wheels are going to gain less than 1% of climbing speed. so even 1 hour of continuous climbing (which is steep enough to lose any aero benefit) would gain less than 20 seconds

Savings will be proportional

Savings will be proportional to the square of the speed, so 27/40 is roughly 2/3 and the watts will be reduced by 4/9.

Just under half the savings at 27kmh than at 40kmh

However, the increase in how good the bikes looks will be unchanged and people will be able to appreciate it for 50% longer

I replaced my ageing 58mm
I replaced my ageing 58mm FFWDs with a set of Cero 35mm wheels. I get most of the aero benefits of running deeper sections, lighter wheels and they’re better suited to the terrain in the Surrey Hills, North Downs and Hampshire.

Thanks a lot for the feedback
Thanks a lot for the feedback!
I’m looking at the Prime 50mm black edition as they seem good for the money, lighter and more aero than the cheaper ones.

I’ll happily settle for slower climbing wheels in exchange for ‘flow’ and speed on rolling undulating flats and fast downhills of which there are plenty. If the wider rim gives grip and comfort too it’s a winner.

I just wanted to feel a difference for the cash!

You only benefit from weight

You only benefit from weight savings over aero benefit on a ride with average gradient over 6%, i.e. for most of us pretty much never.  Maybe for hill climb TT’s, that’s pretty much it.

Remember you’re talking maybe a couple of hundred grams, most of us could easily lose ten times that from our bodyweight!

Aero benefits are far more important than weight, in nearly all circumstances except for very steep climbs.  There’s loads of research out there, much of it independent, and now you can get decent aero rims which are 1,500 grams, it’s not really an either or thing.  

Finally, most contemporary aero rims are fine in cross winds.  My son is only 70kg, and is riding 55mm rims in all weathers.

Hey @Davman, I’d suggest that

Hey @Davman, I’d suggest that deeper rims will make you faster. I’ve had Prime RR50s before now and the weren’t the fastest but I’d imagine they’d be faster than 38s. I’d also suggest that the more ‘modern’ shape of the Prime Black Edition rims might make them faster.

Good discussion!
Good discussion!

I’m thinking about new wheels.
I ride places like the Dales and Peak District, 1-3 hours at 15-18mph average, lots of hills >10%, often hit 40mph down and ride a 2014 carbon bike with da9000. Tight kit and spend time in the drops and tucked in. I like the feeling of speed, even though I’m not the fastest by a long stretch.

It doesn’t seem worth replacing my whole bike, but some of the more ‘affordable’ carbon 50mm rims would update the stock fulcrum 2.5’s. Frame and calipers limits tyre width too.

I’ve concluded weight is near irrelevant at the levels we’re talking about.

Aero is interesting. Gains are small but lots of evidence it affects slower riders more, due to yaw angle and time in the saddle.

I’m struggling to justify the purchase based on small performance performance gains but there are a few improvements.
Aero(ish) 50mm section
200g saving against my wheels.
19mm internal v 17 will give me a wider tyre. Tubeless will also add some comfort.
Wider brake track means tyres won’t catch the blocks in wheel removal.

I’ve had to admit that these changes are marginal for a solo rider and the biggest benefit is looks. I ride alone and fairly remote so it’s purely for me. The other intangible element is ‘feel’.

Still can’t decide if I should do it, but if I do it won’t be based on pure performance.

I think the bigger question

I think the bigger question would be if he has hills. He may save a lot more with lighter wheels.

I don’t feel the difference going at a steady training pace but do feel it in races or when doing intervals.