My carbon road bike seems sluggish

ForumNewbie

I have a Cube GTC Agree carbon road bike (compact) with full Ultegra groupset. It's been annoying me for a while as the chain makes more noise than my steel Audax touring bike (105 and Tiagra components) and for a light carbon road bike it does not accelerate like I think it should and I seem to struggle on the hills more than I do on my much heavier Audax bike.

When off the bike and I try to spin the cranks backwards with my hand on the Cube it just does one complete spin, whereas when I spin the Audax cranks by hand with the same force, it spins much more freely going round more than two full turns. Could that mean that the bottom bracket (a press fit one I think) on the Cube is too stiff meaning I am not able to turn the pedals as easily as they should? Any thoughts or advice would be appreciated.

k-dog

Modern bottom brackets won't spin much - 1 revolution is about right.

But, it produces very little resistance in the real world so that's not the problem.

Matthewfalle

Have you ever used it in the rain or has it been kept somewhere damp/area where it rains a lot?

If so there is your answer.

ElectronShepherd

You don't say if the cranks have the chain on, or if they are free to spin on their own. If the chain is still on, so you're actually spinning the crank, the cassette, two derailleur jockey wheels and lots of links, a single revolution sounds about right. If the chain is off, so it's just the cranks moving, then I'd say it was sluggish.

Is the chain lubricated correctly? I can see a duff chain being both noisy and stiff to move through the rest of the drivetrain.

ForumNewbie

Thanks for the responses.

I was spinning cranks was with the chain on as it does not have a connecting link to remove it easily. I was caught in rain a few weeks ago but dried bike and lubed, but seemed sluggish before that anyway. I gave it a good degrease, cleaned and re-lubed the other day and it seemed better yesterday, so I'll persevere with a bit longer, and if it's still not right I'll take it to an LBS to check it out.

k-dog

Have you checked your rear brake? I replaced my brake pads last night and then rode 15 miles with one side rubbing today - a quick adjustment and it seemed much easier on the way home!

ElectronShepherd

If you put the gearing so that the chain is on the big front chain ring and the small rear cog, there should be enough give in the rear derailleur to enable a helper to pull the chain away from the front crank while you spin the (now unencumbered) crank. That would tell you if it's the bottom bracket or not. With no chain to slow it down, I'd expect the crank to spin round very freely.

ai_1

Matthewfalle wrote:

Have you ever used it in the rain or has it been kept somewhere damp/area where it rains a lot?

If so there is your answer.

The answer could be that the bike was used in the rain?
Care to elaborate?

spanner239

Also check that the chain runs through the jockey wheels on the rear derailleur correctly, especially that it goes the correct side of the little sticky out bit (technical term!) between the two jockey wheels. I have seen this on a couple of built bikes, makes the whole drivetrain really noisy and adds loads of additional friction.

meanredspider

Changing tack completely, what tyres are you running? Tyres like Bontrager Hardcase are 1mph slower than Gaterskins and they ain't quick either. I don't believe an issue that isn't obvious at the BB will be enough to slow you up. Personally I'd start at the wheels and work backwards - tyre, wheel (brake), hub, then rear transmission and BB last of all - just a matter of mechanical gearing/advantage.

Matthewfalle

Ai_1 wrote:

Matthewfalle wrote:

Have you ever used it in the rain or has it been kept somewhere damp/area where it rains a lot?

If so there is your answer.

The answer could be that the bike was used in the rain?
Care to elaborate?

Have a read through this: viewtopic.php?f=40004&t=12972030&hilit

- various different reasons and explanations re hygroscopic properties of carbon fibre contained within together with real life examples and means of prevention of wefting.

meanredspider

Matthewfalle wrote:

Ai_1 wrote:

Matthewfalle wrote:

Have you ever used it in the rain or has it been kept somewhere damp/area where it rains a lot?

If so there is your answer.

The answer could be that the bike was used in the rain?
Care to elaborate?

Have a read through this: viewtopic.php?f=40004&t=12972030&hilit

- various different reasons and explanations re hygroscopic properties of carbon fibre contained within together with real life examples and means of prevention of wefting.

You're talking completely different levels of dampness than 99.99% of carbon road bikes are likely to see. My brother's Trek MTB suffered from water issues in the OCLV frame BUT it stayed outside (unridden) for two years in Vancouver (very wet) AND Trek replaced the frame under warranty. I've not come across a single other example. There's no way that this is the problem here.

frisbee

One of my wheel bearings had almost completely seized up and it was unnoticeable when riding.

Different gearing between the bikes?

smoggysteve

Is the frame the same size as your Audax? If you are not fit well to the Cube bike you may not be getting the same power out of it when you pedal.

mitchgixer6

Matthewfalle wrote:

Ai_1 wrote:

Matthewfalle wrote:

Have you ever used it in the rain or has it been kept somewhere damp/area where it rains a lot?

If so there is your answer.

The answer could be that the bike was used in the rain?
Care to elaborate?

Have a read through this: viewtopic.php?f=40004&t=12972030&hilit

- various different reasons and explanations re hygroscopic properties of carbon fibre contained within together with real life examples and means of prevention of wefting.

Just ignore this guy. He's linking to a post where he talks complete nonsense. Best not to waste your time clicking the link.

Matthewfalle

Sorry Mitch but it's backed up by two other people in there and also HMG and the MOD if you want to do a look around. They tend to know what they are talking about.

You do know what hygroscopic means don't you?

But then again, I'm just trying to be helpful.

mamba80

odd, i ve a CF sea kayak, covered in scratches and about 10years old, it weighs no more now than when i bought it. my mate uses a CF white water kayak and numerous others have paddles made of this stuff... all apparently falling to bits

all 3 CF bikes i have are used in the rain (all over 3yo) and any creaks etc have ALWAYS been traced to wheels/bearings/bolts.

No doubt Airbus/Boeing are bricking them selves as are BMW and various other hi end car manufactures.... shares in Clarkes have soared on this latest news/advice.

tbh i had to check we hadn't gone back in time to April 1st, which is just as likely as your theories.

to the OP check tires/wheels swop over? brake rub, riding position?

mitchgixer6

meanredspider

Matthewfalle wrote:

Sorry Mitch but it's backed up by two other people in there and also HMG and the MOD if you want to do a look around. They tend to know what they are talking about.

You do know what hygroscopic means don't you?

But then again, I'm just trying to be helpful.

Looking at your first post on this thread, you make it seem as though this is clearly the answer! That's not helpful - far from it. Most of us would eat our lids if it turned out to be damp-related. Quoting the MOD is hardly adding to your credibility either. Having once worked for a supplier of military equipment to the MOD I'd say it actually detracts from your credibility.

Matthewfalle

Oh well, never mind. Best carry on proffering further theories. It may just be that the bike isn't actually very good or that it doesn't fit you properly. Or something else. Maybe. Or maybe not.

What kind of extra noise? The rattle you get with all carbon bikes as it's a hollow stiff material or other? Sluggish as in rotational pick up, frame? Bear in mind that just because it's carbon doesn't mean that it's going to be a wunder bike (sorry) - some say that steel is real for a good reason. It's like most things - you may buy something that has a brand or model name that carry kudos but you may have the wrong model/capacity/etc.

Can you ask someone to take both bikes for a spin and see what they say?