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Discussion Starter · #1 ·
I had the chance to try out the giant SLR 0 55 mm wheels and wanted to share my experience in case it was helpful to anyone else out there looking for info.
The guys at my local Giant shop were kind enough o loan them to me and I am set to try the carbon climbing set in a week or so's time as well and will share my thoughts on those too.

This is my fourth season riding - ride about 5-7 Km's a season. Some flat - some lower end climbing.
I weight 195 and ride a Giant defy advanced 3 with 105 and either ride the stock Giant wheels or Fulcrum Quatro. Typically I'll either use Michelin Pro 4 SC or Vittoria Corsa Evo CX in 25 set to 105/100 rear/front.

The Giants were set up with giant's own P-SLR 2 tires - which were new as were the wheels.


I did 2 local rides that i know very well - yesterday's was a flat 75 KM ride and todays was a little undulating with a couple of tiny climbs - and rougher roads.

Sadly - I was not any faster.
But i can say without a doubt that there were some very large and noticeable differences as a result of the wheels. When applying more power - there was definitely a quicker acceleration. I found this exhilarating - and would stomp down to test it out in different scenarios - flats/climbs/going from slow to a faster pace on a climb - gelt like a car with a sensitive gas pedal. I am used to increasing my power and waiting for the bike to catch up.
I don't know if this is a result of a stiffer wheel, lighter bike/less rolling resistance a combo of both or what - but it was definitely there each and every time.

I loved being able to accelerate up a hill - both seated and standing. I am not a strong climber by any means and found this to be quite a boost.

The other difference was in the ride quality. It was much more comfortable overall - yet at the same time felt more lively.

Less road chatter and vibration for sure - bumps etc .. were smoother - and I found the bike to track better and feels little more connected when guiding into turns.

it would have been nice to try them out with tires I am familiar with since I don't know how much of a factor the Giant tires were to any of my observations over the last couple of days.

Braking was just as good as either of my aluminium rims. They set the wheels up with Shimano Carbon pads.

I checked the wheels and they were perfectly true at the end of my rides - and they were fresh out of the box when I tried them.

The hubs were perfectly silent - almost too much so - I prefer a little noise - sometimes lets people out walking/running know that someone is approaching.

Overall i was impressed and am looking forward to trying the climbing set as I mull over my next potential upgrade.
Bicycle tire Tire Wheel Bicycle wheel rim Bicycle wheel
 

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I've used Rubino Pros for several years but bought a new Defy last year that came with the P-SL0 Disc Wheel and PSLR-1 tires . My impression of the Giant tires was that they are slow and handle poorly. I left them on bike for a couple month but noticed a distinct improvement when I switched back to Rubino Pros.

Thanks for writing about the P-SL0 55s
 

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Ageeed about the tires - I swapped mine out a month in as well.
you have the defy pro 0? How do you like it?
2015 Defy Advanced Pro 0. Overall the bike's very nice. Super nice ride but a bit less high speed stability compared to my 2009 Trek Madone (I still miss it a little).

The freewheel on mine was quiet to begin with but is significantly noisier now. (I got it last July).
 

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Sad to say but the accelleration and climbing affects you felt are due to new bike part effect. Physics says there's no significant difference. In fact the rims are probably slightly heavier than your current aluminium rims and would thus accelerate very slightly slower. OTOH the aero gains, while small, are real.

But if you like the feel enough to drop that kind of money on them, do it.
 

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Discussion Starter · #6 ·
I disagree Eric. I have a power meter on my bike and could see the speed/power go up at a quicker rate than with my stock wheels. It was quicker and easier to accelerate. Tried it dozens of times on two separate rides - seated/standing - climbing, sprinting and just picking up in general. Like a gas pedal with a more aggressive/sensitive touch.

Sad to say but the accelleration and climbing affects you felt are due to new bike part effect. Physics says there's no significant difference. In fact the rims are probably slightly heavier than your current aluminium rims and would thus accelerate very slightly slower. OTOH the aero gains, while small, are real.

But if you like the feel enough to drop that kind of money on them, do it.
 

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Power going up more quickly will have nothing to do with the wheels, it means you are working harder. All direct force power meters are measuring power before the wheel. And if power goes up more quickly then so will speed. So if you wanted to verify that the wheel indeed accelerates more quickly you would need to keep your power ramp constant and then look at the resulting speed. I won't be holding my breath.
 

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Discussion Starter · #8 ·
I think you misunderstood me.
I can see the speed increase quicker as I applied more power. Quicker as compared to my other wheels.

Power going up more quickly will have nothing to do with the wheels, it means you are working harder. All direct force power meters are measuring power before the wheel. And if power goes up more quickly then so will speed. So if you wanted to verify that the wheel indeed accelerates more quickly you would need to keep your power ramp constant and then look at the resulting speed. I won't be holding my breath.
 

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I think you misunderstood me.
I can see the speed increase quicker as I applied more power. Quicker as compared to my other wheels.
Ok, let's see some plots of power and speed versus time between the two wheels. Make sure position, clothing, tires, tubes, and all environmental conditions remain constant between the tests. Oh, and don't forget to blindfold yourself and have someone else switch the wheels and tires for you so you aren't biasing the results. What you should really do is hook the wheels up to an instrumented electric motor and take some data. Much more repeatable. Again, I'm not holding my breath.

If you're looking for an excuse to buy some new bling wheels go for it, but as ericm979 said quicker accelerations have no basis in reality.
 

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I think you misunderstood me.
I can see the speed increase quicker as I applied more power. Quicker as compared to my other wheels.
You're misunderstanding him. If you apply more power your speed will ramp us as a result. Since your power output is not affected by your wheelset, your speed is ramping up quicker due to the increased power you apply, not the wheels. Here's the TL;DR, it's impossible for you to test your claim as you'll never be able to ramp up the power in the same conditions when stomping on the pedals. This simply isn't possible for a human being.

I understand where you're coming from and why you think you're ending up with this conclusion. I have a heavy training wheel that needed repairs. My friend lent me some Zipp 202s while I got it back and it definitely feels more snappy when accelerating but in reality this slightly increased acceleration means squat in the real world. This wheelset is a good ~300g lighter than my training wheelset.
 
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