Upgrading road disc wheels (replacing Giant PR-2)

Discuss light weight issues concerning road bikes & parts.
Stickman
Posts: 64
Joined: Sun Oct 08, 2017 1:58 am

by Stickman

The wheels have arrived!!! I'll take them to the LBS tomorrow to get them built up, but according to my scales this is what I've got:

Prime RP-38:
Front - 856g (705g wheel + 115g Ultegra rotor & lock ring + 36g QR skewer)
Rear - 1291g (845g wheel + 115g Ultegra rotor & lock ring + 41g QR skewer + 290g Ultegra cassette)

Compared to stock Giant PR-2:
Front - 1095 incl disc rotor and QR skewer (239g heavier)
Rear - 1625g incl disc rotor, QR skewer and 105 cassette (334g heavier)

= 573g weight saving

They're tubeless compatible but I don't think I'm ready for that leap yet, so they'll be shod in tubes and Conti GP4000sII with the reflective sidewall strip.

Can't wait to give them their first test ride. The stock wheels will go into the spare room in case of emergency.

g00se
Posts: 31
Joined: Fri Feb 21, 2014 11:22 pm

by g00se

I saw the thread and was going to recommend a set of Primes - I've got the 50s. Great value for wider tubeless carbon hoops.

by Weenie


alcatraz
Posts: 974
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

1550gr for a 38mm wheelset with disc brake hubs is ok.

If you haven't overpaid then good job.

The rotors seem heavy to me though. I'd put lightweight butyl tubes in @50-70gr. Maybe veloplugs instead of rim tape.

/a

Stickman
Posts: 64
Joined: Sun Oct 08, 2017 1:58 am

by Stickman

Here are the Primes on my not very weight weenie road bike :D First ride will be a 13km commute tomorrow morning. Looking forward to seeing how they feel.


Image

Stickman
Posts: 64
Joined: Sun Oct 08, 2017 1:58 am

by Stickman

So far so good. Losing 600g off a chunky-monkey ~11kg system weight (saddle bag, lights, bidon etc) mightn't sound like much but when it's rotating mass, I'm pleased to feel such a noticeable difference.
On familiar roads, these wheels are much more able to hold speed, and I don't need to get out of the saddle or gear down every time the road points slightly upwards.

The big test will be this Sunday's 135km hills sportive.

alcatraz
Posts: 974
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Nice looking bike. That rear light looks a bit bulky. You could get a smaller more aero and chargeable one with straps around the seatpost.

Sure the seat is comfy? Looks like the nose could come down a tad and the whole seat coule come higher a few mm.

Right shifter looks to be a bit lower than the left. :smartass: :lol:

When you are sure this position fits you it'll look nice with the steerer cut. :)

/a

Stickman
Posts: 64
Joined: Sun Oct 08, 2017 1:58 am

by Stickman

The new wheels performed beautifully on the weekend's hill sportive. 135km with 1500m of elevation, 4 particularly nasty climbs, and they were magic. Really transformative. Considering the bike (as I ride it) is still around 10.5kg, even after losing ~600g off the wheels, it felt so much lighter on the climbs. Transitioning from descent to climb was smoother and I maintained speed far easier, whereas the stock wheels feel like someone's grabbing the back of my jersey as soon as the road tilts up! Out of the saddle efforts and seated acceleration to overtake other riders was amazingly responsive, and I never felt like I was struggling to turn the pedals over (except the obvious terrain). The feeling of having to fight the bike up hills is gone.

Seeing as I'm still the same low powered engine providing the power, I'm amazed at just how much these new wheels have totally transformed my bike. N+1 can wait with no regrets now :)

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