4rensho@gmail.c

I am building up a randonneuring bike and currently in the process of building the wheels but have run into a fork in the road concerning rim depth and suppleness. The wheels I am building feature an SP SV-9 dynamo hub in the front and a Dura-Ace 9000 hub in the rear at 20 and 24 holes respectfully. I have the choice of two different rims that are currently built up to different hubs that I dont use. 1 is campagnolo proton wheelset with a box section rim with eyelets and 2 is campagnolo zonda rims with a semi shallow aero profile and no eyelets. My question is which would be better for my build? This will be a bike that I will be using for 300+km brevets and Both seem equally alluring. On the one hand the proton rim would be more playable and forgiving after a long ride and the eyelets are a plus as far as strength go, but they are not at all aerodynamic. The zonda rims are aerodynamic but I worry after 10+hrs in the saddle the ride will be haring and I will regret using a deep section rim. As well durability plays a part. Are eyeleted rims all that stronger or is it a placebo effect? Would the aero gains be with the uncomfort? Two weeks ago I completed a 300km brevet on sun m13 36h rims in 11hrs 9min and have a goal of sub 30hrs for the 600k. Which do I go for? The aerodynamic or the box section "reliable"? Please help.

znomit

Is anything really aero at Rando speeds?

GhostRider62

At 11 mph, half your power is to overcome the wind.

OP wants to do a sub 30 hour 600K, that means he needs to ride the flats at over 20 mph. Aero is critical at that speed.

So, yes, he needs to consider aerodynamics carefully. I've done 600k in under 23 hours and 400k in under 14 hours and aerodynamics played a role in both.

rm -rf

Can "compliant" rims really make a difference, compared to supple tires at the correct pressures? What fraction of a mm would the rim move on a bump?

I don't do these long rides. Do you choose stiffer puncture resistant tires or flexible supple ones? Speed vs flat fixing?

GhostRider62

Rim choice is largely irrelevant for comfort, it is tire construction, size, and pressure

A wider rim plumps up the tire and that helps but wheels are pretty much noncompliant radially.

Personally, I would never use anything but carbon rims anymore. They are much stronger than alum and especially with 16, 18 or 20H fronts.

Branko D

I would pick a 45-50mm deep carbon rim with no nipple holes for ease and reliability with a tubeless setup, with a relatively supple road race tire with some puncture protection (eg GP5000S or similar) and lower the tire pressure until it isn't jarring to ride.

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