[Closed] Please help me diagnose a problem or exorcise a demon.

Have you weighed them for comparison?

Yeah, disc bikes are heavier, possibly as much or more difference than alu vs carbon frame and wheels?

Or perhaps just the rim weight is higher so they feel slower to spin up?

Have you checked your bottom bracket and drivetrain isn’t shagged?

Also, is the geometry/riding position similar on the old and new bikes?

Could the new one be more relaxed or upright?

Unless you have some hard data this one is a bit tricky to solve.

35mm

This will be as aerodynamic as a brick.

Get some 23mm tyres on some sensible sized rims. All this "wider tyres are faster" stuff is just nonsense unless you're going off-road.

Presumably he means 35mm deep, not tyre width.

What tyres on both?
Are you saying you have tubeless in alu bikes and cheap tubes on carbon bike?

I’ve tested bikes back to back (MTBs) and the ones that felt slower were actually faster (Strava comparison disclaimer)

Given Strava is free and you can run it from a smartphone on your ride surely it's very easy to add some basic data comparisons to see whether it is in your head or not. Clearly you'll have to judge the effort you're putting in though.

If you've spun the rear wheel in the stand to check drag, have you tried pedaling it? It could be drag from the freehub bearings.

Presumably he means 35mm deep, not tyre width.

That makes more sense.

Perhaps worth checking that the rear wheel isn't flexing(*) and rubbing on the brake pads. Adjust the pads further apart.

(*) Or the frame is flexing around your very stiff carbon wheel.

The road bike in question is at least 2lb lighter than any of my other bikes. The other bikes are all disc. The Phantom Bike is the only one with caliper brakes. All the road bikes and the 'cross bike are set up the same. Within a few mm anyway, following a bike fit.
The drivechain has done around 1000 miles. No play in the bb. The chain length is good etc. This bike had the basic Shimano (circa £100) wheels which were replaced with the Prime carbons. I was expecting a significant increase in performance. I'm still waiting. It's been around 3 months since they were swapped. Disappointing from the outset.
The only thing I can think of is that the carbon wheels have basic £5 inner tubes fitted as I couldn't get the Hutchinson tyres to seal tubeless and I nearly broke fingers getting the tyres on and off where ALL of the other wheels are tubeless. Would tubes make that much of a difference?

edit: 35mm depth rims, not width, sorry. Everything feels fine in the stand. BB spins easily, as do the wheels. It is definitely harder work on the expensive road bike. I'll move the pads even further out although they're very 'open' as it is but it's worth a go.
I'll try running a stopwatch on the same stretch of road with different bikes.

That's the size of it Matt. Hutchinson Fusion something or other. 25mm width. Cheap tubes in the tyres. All the other bikes are tubeless

Geometry. I bet the saddle position isn’t the same so you are using slightly different muscles and may have different handling.

What is the head tube angle on the bikes? What is the seat tube angle? Are you in the same position over the BB? Is the reach the same if you are? Are the stems the same length if the reach is the same? Weight over the front wheel will influence was handling and change the feeling of the bike.

It’s probably perception btw. If you are as aero, and the geometry and position is the same, then tyres will account for up to about 10% at most. If you have high quality branded Kevlar beaded tyres then tubeless won’t matter. When I swapped some OEM wired Schwalbe Lugano tyres for some GP5000s there was a reduction in power of about 20 watts for the same speed. You won’t see that difference from tubes to tubeless, unless you have some seriously heavy nasty tubes (decathlon £1.99 for example)

I hadn’t thought of geometry actually.
The tubes are definitely from Decathlon and may have been less than £5 each..... is this the problem? It would be both great and not great if so. Great because it will be fixed but not great because I’m going to have to cut those tyres off. I have four different types of tyre levers, all proclaiming to be the lever that will work on any tyre.... it still took two burley blokes and a lot of pain to get the tyres on.

I’ve tested bikes back to back (MTBs) and the ones that felt slower were actually faster (Strava comparison disclaimer)

This. I don't ride road bikes, but the perception of speed and effort has little relationship to what the stopwatch shows.

If the tyres are that tough to place, how were you planning on fixing a roadside puncture...? Maybe they need to come off anyway and get donated to someone else whose rims they do fit..

I don't bother taking a tube or a pump when I go out on this bike. No point. I keep my ri9des on it fairly local and use a different bike for my bigger rides.
I'd happily donate them to somebody else when they do come off but they'll be cut in half.

This bike had the basic Shimano (circa £100) wheels which were replaced with the Prime carbons.

Still got these? Can you try putting them back on? What did it feel like before you swapped, better, worse or the same?

I sold the original wheels.
From the first ride, I've been completely underwhelmed. A total contrast to the other three Prime disc brake wheelsets that I have. They're considerably better than those they have replaced on the disc braked bikes.
I'm beginning to think it could be the inner tubes (would that really make such a difference?) but I also wondered if there was possibly a problem with the bearings or freewheel. Is there a way in which it would only cause issues when the bike is weighted and/or the drive train is under tension?
I doubt it is flex in the frame but I'll definitely have a look at that over the weekend.
I'm tempted to sacrifice the tyres, buy new and see if I can set them up tubeless.

Doubt it's the tubes personally.

Can you slam the stem on the new bike, that brought my old Defy to life after what had been a sluggish start feeling underwhelmed.

And do the Strava test suggested above before you start spending money based on what might be a misconception.

Cheap tubes might be no more than 10 watts. That is barely perceptible. Geometry would be my first bet for “feel”. Data will probably show there’s nothing in it. But geometry trumps weight for a nice handling bike.

If the slow bike has tubes and the fast ones are tubeless, surely that's the answer.

From my racing days, the best single item upgrade for any bike for me was tyres. Go and buy some real racing tyres and ride it with them one. I'm out of the loop as regards really good tyres these days, but choose the top of the range race tyre from anyone and, as above, don't go silly widths; 25 or 28 will be fine.
Tubeless tyres....meh.... top of the range clinchers with decent tubes were good enough for racing on...

Sounds obvious (surprised no-one has mentioned it yet?), but are you sure the gearing is exactly the same between bikes? Slightly different chainring or cassettes can make a huge difference in feel.

But the clock never lies, so you won't know if it is actually slower until you measure times.

Get yourself a pair of power meter pedals and a 10 mile tt course. You’ll soon be able to work out the difference. And it won’t be your tubes.

I would imagine it’s all perceived - once you start using gps the picture will be pretty clear.

What tyre pressure are you running, a road bike with tubes should be up around the 100psi mark.

Tubes and tyres are too negligible, even if they are cheap tubes, the tyres are more than decent.

Are they the Prime SE's with the very cheapest Novatec hubs? I reckon that as they all work fine in the stand, that when you're on the bike the wheel bearings are loaded and are binding under load.

As you don't do electronic recording, do you have a basic wheel on trainer? If so, check it all over in the stand and then mount it on the trainer and have someone ride it while you look for obvious binding of the rear wheel bearings.

Perception is of little value at this point, you need to go out over a timed circuit and see whether it really is slower or if your perception is fooling you. It's been done many times with FS vs HT where HT feels faster but FS actually is, you need to do the same here.

After that it'll either be proven or not; then perception becomes important. In the sense that it'll either change your perception when you see the evidence that it is faster, or that it won't and you still won't enjoy riding it / them no matter what- and it's about smiles, not miles after all?

Trying to find out why they're slower when there may be nothing to find is a waste of effort at this point.

I am wondering if putting a cheapo tube inside a TL tyre is not helping.
Tubeless tyre built slightly heavier to run with sealant , and add the weight of the tube
Now possibly add in the factor of slightly rubbing brakes on the rims, with possibly bearing drag once weighted.
How you check for bearing drag weighted? Oh a roll down test. Flat road. 15mph , reach line, roll to standstill and mark spot, get other bikes, rinse and repeat. see who goes further.

My 2p's worth . Buy 2 x Michelin Power Race tyres and latex tubes to make the ride come alive.

and as for not having a bike you ride very far so wont need to fix a puncture , have a word with yourself

I had a very similar thing on my road bike.

Swapped my synchros alloy wheels for a set of 50mm carbon ones. Ran the same tyres on both sets. The carbon ones felt slower from the start and very rough Strava data supported that. I ran them for a few months then swapped back and sold the Carbon wheels.

Maybe some frame and wheel combos just don’t work? Who knows.

The reason I mentioned pad clearance earlier was that on my bike, I wound the pads in to just a few mm after changing them, and the next ride the bike was very slow.

After about an hour of riding around wondering what was going on, I wound them back out and it was immediately back to normal.

EDIT: this seems to be a thing, because carbon wheels are a lot stiffer than aluminium ones, so end up rubbing more.

Thank for tall the tips, suggestions and advice apart from "and as for not having a bike you ride very far so wont need to fix a puncture , have a word with yourself"

There's always at least one. 30 miles out and 30 miles back is about my limit on this bike. I can mitigate a puncture with a bit of a walk and a train ride home, should the need arise. If I'm doing my every other weekend 100 mile ride, I'll take another bike. This is only going to be going on for a few more weeks because if I can't sort it out, either in my imagination or in real terms, the wheels will be passed on with full disclosure.

Thanks anyway for your partially kind advice and thank you to everyone for your helpful suggestions.

Do you want to borrow my wheels to try them out?

Nowt fancy, Ksyriums with S-works tyres, 11 speed.

Crikey! Mate! Lovely to hear from you again! That could be a great idea. Maybe even a permanent swap (worth a punt)?

I'll see how I get on but if nothing seems to work, can I give you a shout to try it out? I'm really grateful.

Hi!

Probably no to a permanent swap; they have been used and abused, but yes, no problem if you want to try them out for a while; I'm not really riding very much at the mo, so it's not a big issue.

I've still got the same e-mail addy... (and the bivvy bag!)

Have you noticed any wear marks on the side of your tyres? Could be, as someone already suggested, the tyre rubbing against the frame if the clearances are tight.

This is a perceived feeling

If it's a "perceived feeling" all you can do is change your perception. I think the conventional solution to this is to buy an expensive upgrade. This will usually make the bike feel faster.

What tyre pressure are you running, a road bike with tubes should be up around the 100psi mark.

That's very old school, especially with the wider tyres that most people are using these days. I've dropped my pressures significantly in recent years. The bike seems to roll fine, and it's a more comfortable ride.

What tyre pressure are you running, a road bike with tubes should be up around the 100psi mark.

I run both my road bikes at around 70psi (25mm on one and 28mm on the other). Neither bike feels slow.

Advice on here has been to run 23mm tyres and increase psi to 100. Are we still in the 90s?

I've yet to try some Hutchinson tyres, keep thinking of trying the Storm 11 All Season tubeless on my Hunt Aero Light Disc wheels, so no idea how they roll.

But I can feel the rolling resistance difference between 28mm GP4000S IIs with latex tubes and 4 Seasons with cheap butyl tubes. Just the nicer tyres alone with the same tubes feels quicker.

My 58cm Cube has a silly high stack of 610mm and currently I have all but a 5mm spacer under the stem. Compared to an aero bike with a slammed stem, I'm about as aero as a brick and have to put out plenty more than 180W to do 20mph on the flat in near windless conditions. I'd love something like that ~£1500 Giant Propel Disc at Rutland, but I'm not sure my lower back would love it!

With respect to all the thoughts and suggestions, surely with nothing beyond 'feel' to go on there is little point messing about with kit.

As has been mentioned, why not download Strava to a phone, place it in a pocket and go for the same ride on different bikes etc. If you make a note (say score out of 10 to make it quantifiable) of how you felt it went, both in terms of physical effort, comfort and enjoyment before you look at the Strava results, you'll quickly be able to see what your dealing with.

It could be that one bike is a bit 'dead' in feel with the way it is built, which leads you to believe it is slow, yet in actual fact the data suggests otherwise.

Then when you have data to hand, you can combine all the info and decide if you prefer speed over comfort and quality of ride etc and if you then need to start swapping components to give you what you want out of a bike and a ride.

I have a resolution! Thank you all for your input.
The bike came with 23c tyres but I had fitted 25c Hutchinson Intense 2 tyres to the carbon wheels before trying them out. Because of my pretty useless cleaning regime, I hadn't seen that the shoulders of the rear tyre had worn.... . The frame needs a check over. This could be nasty.
I cleaned everything. I put the bike on the turbo with my phone held in various positions while riding by my able assistant (daughter - cost me £5) and the the rear tyre was rubbing the frame. I swapped the tyres (after a lot of effort and swearing) for some Continental Gatorskin in 23c with the same inner tubes and it instantly felt easier out on the road and I also have the added benefit of being able to remove these tyres roadside if I have a puncture.
I am surprised though that at the level of drag I'm sure I could feel and how little it has damaged the frame, even though it's done enough for me to have it checked out. I know what I mean.
Thank you again everyone.

Gatorskins!

Get some lovely tyres, stop messin' abaaat!

So it was rubbing because there wasn't clearance for 25mm in the rear?

edit: just read the full thread, glad you're all sorted.
Hi Monksie. 🙂

So it was rubbing because there wasn’t clearance for 25mm in the rear?

Yes

From what I've read, GP5000s come pretty true to size, unlike GP4000S IIs... So look out for a good deal on at least one 23mm GP5000.

https://www.merlincycles.com/continental-gp5000-folding-clincher-road-tyre-700c-127979.html Currently £36.50

Hi James 😀
Have I bought rubbish tyres?

crikey! glad you got an answer even if not a full resolution monksie!

Phew! I was about to offer you the loan of a spare set of wheels to see if that helped.

Gatorskins? Old school puncture-resistant winter commuting tyres in a slippy in the cold and wet sort of way. I use GP4000s all year round here and they're lovely and grippy and as we don't have sharp flint and similar debris on the road, they don't seem to puncture any more than anything else.

I've never really got the trad winter roadie thing where you ride nice grippy tyres when the roads are dry and grippy and swap to something with half the grip as soon as it's cold and wet when, arguably, you benefit more from grippy rubber. Then again I mostly ride my cross bike on the road in winter, so what do I know?

Thank you for the offers and potential offers of wheels to try. I’m going to have to put up with the tyres I’ve bought until the summer. I’ll kid myself that they’re good for resistance training without wearing a further hole in my frame.

Well I'm glad we got to the bottom of that anyway.

If you're after something marginally narrower, I have some spesh s-works turbo 24mm which are very lightly used.

Drop me a line if they might be of interest for cheap-ish?

Yay
You can carry a pump and tube now to avoid the walk ( and train ride) of shame
Glad you got to the bottom of it
BTW what frame has tight tolerances that a 25 will rub to cause braking effect?

Well OP, I'm glad you know what the problem is but I was kind of hoping that we'd find out that your bike was haunted by the ghost of one of your old bikes.

Ha! It’s a BMC Street Machine or something similar sounding.
To be fair, The Hutchinson Intense tyres are very wide for a 25c.

The Prime wheels are probably 25mm or 27.5mm wide at the rim bed if they are relatively new so the tyres will probable run much wider than the 25mm written on the side of them. The bike might be a bit older and not designed for the newish trend in wheel width.