Please help me diagnose a problem or exorcise a demon.
Happy New Year!Posted 8 months ago
My road bike, fitted with Prime 35mm carbon wheels is noticeably slower than any of my other bikes. This is a perceived feeling as I don’t use GPS, bike computer or power meter. I can feel that it needs much more effort than my other bikes with the only difference being I have basic tubes in the carbon road wheels and my other bikes have Prime aluminium (I’m a fan of Prime wheels until this) tubeless set ups. Even the ‘cross bike is easier but I wouldn’t have thought it would make such a noticeable difference. It is clearly noticeable. I’m not imagining it. Honestly.
Sadly, there is only this bike with caliper brakes, the others are all disk so I can’t swap wheels to try it out. They seem to spin fine in the work stand and the BB seems fine as well.
Any ideas why this bike is such hard work? It’s full carbon and all things being equal, should be much quicker / less effort.
I’m going slowly madder around this. It’s becoming an obsession.
Have you weighed them for comparison?Posted 8 months ago
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?Posted 8 months ago
Have you checked your bottom bracket and drivetrain isn’t shagged?Posted 8 months ago
Also, is the geometry/riding position similar on the old and new bikes?
Could the new one be more relaxed or upright?Posted 8 months ago
Unless you have some hard data this one is a bit tricky to solve.Posted 8 months ago
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.Posted 8 months ago
Presumably he means 35mm deep, not tyre width.Posted 8 months ago
What tyres on both?Posted 8 months ago
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)Posted 8 months ago
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.Posted 8 months ago
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.Posted 8 months ago
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.Posted 8 months ago
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 tubelessPosted 8 months ago
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)Posted 8 months ago
I hadn’t thought of geometry actually.Posted 8 months ago
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.Posted 8 months ago
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..Posted 8 months ago
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.Posted 8 months ago
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?Posted 8 months ago
I sold the original wheels.Posted 8 months ago
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.Posted 8 months ago
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.Posted 8 months ago
If the slow bike has tubes and the fast ones are tubeless, surely that’s the answer.Posted 8 months ago
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.Posted 8 months ago
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.Posted 8 months ago
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.Posted 8 months ago
What tyre pressure are you running, a road bike with tubes should be up around the 100psi mark.Posted 8 months ago
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.Posted 8 months ago
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.Posted 8 months ago
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 yourselfPosted 8 months ago
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.Posted 8 months ago
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.Posted 8 months ago
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.Posted 8 months ago
Do you want to borrow my wheels to try them out?
Nowt fancy, Ksyriums with S-works tyres, 11 speed.Posted 8 months ago
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.Posted 8 months ago
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!)Posted 8 months ago
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.Posted 8 months ago
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.Posted 8 months ago
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?Posted 8 months ago
You must be logged in to reply to this topic.