A week ago I bought a second hand CAAD8 with 16 speed Claris. Pretty decent stiff/light frame (with surprising comfort) and even as a complete bike it isn’t hugely heavy. This will be the bike I take away when ride abroad and might end up being left in Spain.
The bike however feels really hard work on anything uphill. It is way way more effort to maintain speed and accelerate than any other bike I have had. On the flat and downhill it’s not as noticeable.
The gears are a bit rough and spacing slightly wider than I am used to of course, but I wouldn’t have thought this makes a huge difference.
The wheels are apparently a smidge over 2kg naked, the tubes are likely thick cheapies, the tyres are 23mm Schwalbe Lugano.
For reference I am used to a CAAD12 with 11 speed, 1.5kg shallow wheels, ultralight tubes and 25mm Schwalbe Ones (measure 27). Position is fairly similar between both bikes, within 2 cm on stack, 1 cm on reach and although saddle is different it has same setback and height (based on sitbones, not saddle tip).
To quantify it, the CAAD 8 to CAAD 12 is in the region of 3-4km/h slower and RPE is up maybe 20% whenever there is the slightest include!
What is likely to be making such a huge difference?
I agree with your assumption that the two bikes should not feel that different. The difference shouldn’t be more than having full bidons vs. empty ones on the bike or something like that.
Did you make sure there is nothing mechanically wrong with the bike? Like checking for rub (wheels and brakes, especially under load like when climbing), spoke tension, integrity of bottom bracket and chain?
Mechanically it seemed ok on a stand but that doesn’t mean a bearing I can’t see isn’t dry and unhappy when warm!
Looking at ride in more detail (it was 30 miles so long enough to see patterns) suggests downhill parts I was doing my typical sort of speeds, uphill is where it slowed.
I’ll try swapping the tyres over soon and see how it feels. Plan with this bike is to chuck my spares on to make it 11 speed 105ish spec. The wheels on there have an old hub that won’t take 11 speed so will have to be swapped out.
As per the original post my main thoughts where why is the difference so big, so will try doing tyres and tubes on their own first, see if they really make that much difference.
Tyres, tubes and wheels make a huge difference. I used to use the same bike for racing, training and commuting on crappy roads. For training and commuting I ran a set of Mavic Open Pro wheels with butyl tubes and Gatorskins, for racing I switched over to 30mm carbon wheels with latex tubes and GP4000 tires. Everything else the same. Was like a different bike - I used to reckon on at least 1mph of free speed, but felt like more because the ride quality and cornering were also so much improved.
I do remember the difference on my first road bike of going from Giant low end wheels with tyres over to Mavic Ksyrium SLs with GP4000s, but it is nothing like as much difference as between my two bikes currently.
Looking forwards to trying out other tyres and seeing if it makes a huge difference alone.
The Lugano might be the worst tire Crr wise in a long list of tires. To be fair, I’m not familiar with the low end Giant tires. Anyways, point is, I learned many years ago the tire and tube are the most noticeable component of a bike when you go from bottom to top shelf. Let us know how the bike rolls with the Ones.
A few winters ago I took my CX bike (a CAADX) and put on some Nokian studded tires and Bontrager Thorn-Proof tubes. I instantly felt like I had spent the last few months eating pizza and drinking beer, without the actual benefit of drinking beer and eating pizza. So I also suggest putting on similar tires/tubes before making any comparisons. Also check the condition of the drivetrain and be sure it’s clean, lubed, and properly adjusted.
I had a quick read up and the thread I read suggested only the r7000 11-34 fits a 10 speed hub (as is a rebranded slx cassette). If so that’s a bit annoying as I have an 11-30 sat in my garage ready to fit and could just as easily bought the other.
The issue is the 11 speed hub is 1.85mm longer than the 10. On the R7000 cassette there should be a 1.85mm recess at the back of the largest sprocket. To fit r7000 on an 11 speed hub you should always need a spacer… at least from my reading. I’ll be putting it to the test myself soon enough.
I did try with a set of Schwalbe One tyres on some 31mm deep Giant rims (off a TCR I think) and it was a couple of km/h faster for same perceived effort but still not what I am used to.
The Giant wheels however fell apart within 10 miles, a handful of spokes ended up with almost zero tension and had to spend 10 minutes at the roadside putting tension in and vaguely truing them so could get home.
Going to stick my trusty DTs on it and try again - but that will be with 105 and 11-28 on the back (found 12-25 means spinning out top gear and grinding a little in bottom).