Descending on a carbon frame

LDB

I'm wondering if it’s more difficult/ takes more skill to descend on a carbon frame. As carbon is lighter does it tend to wobble and lift off the road more thus causing difficulties?

Do people find it easier on steel / aluminium?

I don't ride a carbon frame myself but I'm interested to know.

blorg

Generally, I wouldn't think so. A carbon frame in and of itself doesn't necessarily drop that much weight, particularly off the entire bike+rider combo. You might be looking at a water bottle worth of weight reduction. I've hit my max speeds descending on my lightest carbon bike, don't go quite as fast on the titanium tourer or aluminum fixie

Raam

My problem is the damn thing seems to take off, i.e. it flies down the road and gathers speed so easily.

Gavin

Yeah gravity is scary stuff. What's particularly scary is traveling extremely fast and knowing that you need to slow down. But also knowing that applying the brakes too hard will result in losing control. This is particularly bad when the road surface is poor and a bend is rapidly approaching.

unionman

Raam wrote: »

My problem is the damn thing seems to take off, i.e. it flies down the road and gathers speed so easily.

Glad to know I'm not the only one who finds that a slightly overwhelmng sensation. I have a problem with 'fishtailing' - happens mainly because I panic on the descent, flash the front brake and it gives a little kick out the back. Getting better at controlling it though.

smithslist

Raam wrote: »

My problem is the damn thing seems to take off, i.e. it flies down the road and gathers speed so easily.

+1

LDB wrote: »

I'm wondering if it’s more difficult/ takes more skill to descend on a carbon frame. As carbon is lighter does it tend to wobble and lift off the road more thus causing difficulties?

You shouldn't really concern to much about goin downhill.....I would be more thinking bout the weight (more\less, steel\carbon) going up the hill!!!!! :)

LDB

blorg wrote: »

Generally, I wouldn't think so. A carbon frame in and of itself doesn't necessarily drop that much weight, particularly off the entire bike+rider combo. You might be looking at a water bottle worth of weight reduction. I've hit my max speeds descending on my lightest carbon bike, don't go quite as fast on the titanium tourer or aluminum fixie

full water bottle or empty?!

does carbon hug the road just the same as titanium, aluminum etc

CheGuedara

Don't have problems myself decending but I know some lads who've had speed wobbles at 45mph+ going downhill. Scary scary stuff. Seriously dented confidence. Don't know if the bikes being carbon were the route of it though (are carbon Colnagos/BHs unstable compared to alu?). Maybe more to do with shorter wheelbase found on higher spec carbon bikes??

Raam

LDB wrote: »

full water bottle or empty?!

does carbon hug the road just the same as titanium, aluminum etc

I find that bumpy roads where I can't see the bend exit are worst. A greasy surface doesn't help either.

LDB

Raam wrote: »

I find that bumpy roads where I can't see the bend exit are worst. A greasy surface doesn't help either.

suppose that would be the same, carbon or not.

72hundred

Raam wrote: »

I find that bumpy roads where I can't see the bend exit are worst. A greasy surface doesn't help either.

+1

...and imagining there's a lovely hidden tractor doing 2mph around the corner keeps me on the brakes all the way down on descents like those!

Also its funny how the grease (cow crap, water, oil) always pools at the bottom of the descent where the (blind) bend usually is! Dang gravity gets us at every chance.

Cadex

Hi, I bought my first carbon this May (Ridley Orion) having had 5 years on my Aluminium frame with carbon fork (Lapierre Tech3). It was a revelation - they are lovely (or at least, it is) to ride! Uphill it feels much better than the aluminium and downhill (although I would not be the bravest) it is also really good. I find that it seems to hold the road better and that there is less vibration/ feedback from the road This may be due to the carbon absorbing the shock better than the aluminium. What I find is that because it is smoother, I have more control and wth more control I can be more confident and go more quickly.

So the answer, in a nutshell is, No - they (in my experience) are actually better.

DirkVoodoo

I was talking to Cadex about this on the saturday spin because we both have the same bike. I think there is about 2kg in weight between my current and previous bikes and I definitely "feel" the front end of my ridley is a bit twitchier going downhill. I wouldn't be the heaviest bloke in the world (about 10 st. 9lbs last count) so I think the 2kg might be more significant for those of us on the lighter end of the scale. Still, it could just be that the Ridley is more responsive than the SCR 2.0 it replaced (its much smaller too).

Funkyzeit

I love descending on my Carbon frame it's more the thought of shattering IT than my hollow head...wonder if a helmet would help...maybe a poll might be a good idea...;)

tunney

CheGuedara wrote: »

Don't have problems myself decending but I know some lads who've had speed wobbles at 45mph+ going downhill. Scary scary stuff. Seriously dented confidence. Don't know if the bikes being carbon were the route of it though (are carbon Colnagos/BHs unstable compared to alu?). Maybe more to do with shorter wheelbase found on higher spec carbon bikes??

More likely to do with the riders and not the bikes.
Getting fast, they get tense, then the handling of the bike goes...

Raam

tunney wrote: »

More likely to do with the riders and not the bikes.
Getting fast, they get tense, then the handling of the bike goes...

Sounds like me.

CheGuedara

tunney wrote: »

More likely to do with the riders and not the bikes.
Getting fast, they get tense, then the handling of the bike goes...

Maybe so, they're experienced lads but I might ask them how they get when the speed gets high. I've never had the same issues, carbon racer and all on the same roads.

The Connor Pass desent (from either the north side into Dingle or South on to the Tralee side of the peninsula) is a fast one to get the scare on though....

Junior

Meh, never had any issues with the trek. Only bother I've had with control was crossing a white line in the rain and I got a slide .. Not a pleasant feeling I tell thee..

CheGuedara

Junior wrote: »

Meh, never had any issues with the trek. Only bother I've had with control was crossing a white line in the rain and I got a slide .. Not a pleasant feeling I tell thee..

A clubmate went down in the wet like that. On some bitumen patching on a road where a trench had been dug, filled and patched. Was going fairly hefty at the time and just came across the line in moving up through the group, and wham, straight down. Not fun waiting for the ambo. [without getting into the helmet argument - yes, they are a good idea & probably meant we weren't calling a priest instead].

RobFowl

Cadex wrote: »

Hi, I bought my first carbon this May (Ridley Orion) having had 5 years on my Aluminium frame with carbon fork (Lapierre Tech3). It was a revelation - they are lovely (or at least, it is) to ride! Uphill it feels much better than the aluminium and downhill (although I would not be the bravest) it is also really good. I find that it seems to hold the road better and that there is less vibration/ feedback from the road This may be due to the carbon absorbing the shock better than the aluminium. What I find is that because it is smoother, I have more control and wth more control I can be more confident and go more quickly.

So the answer, in a nutshell is, No - they (in my experience) are actually better.

I've ridden Raleigh steel 531, dynatecks (bonded alloy never caught on ), cannondale aluminium (Caad 2 and Caad4's) as well as aluminium cross bikes and MTB's. I have a Ridley excalabur at then moment and I've found it handles descents better than any of the others. Agree with Cadex far less road vibration and feels stiffer.
PS A mate had a 1990 Cadex carbon fibre still going strong !!!

Lumen

I haven't ridden a carbon frame, but...

I don't see how frame material/weight can make that much difference. Surely wheel weight and geometry are more important?

Maybe it's correlation rather than causation. A carbon frame is more likely to have an racy geometry, and be paired with light wheels, the combination of which may be more bum-clenchy on a descent.

That said, a light bike will give a higher centre of gravity. For bike + rider reduced to two masses of 10kg@0.5m + 70kg@1m, CofG is 937.5mm, whereas with 7kg@0.5m + 70kg@1m, CoG is 954.5mm. The 17mm increase in CoG with a lighter bike could be significant for handling.

CheGuedara

Lumen wrote: »

Maybe it's correlation rather than causation. A carbon frame is more likely to have an racy geometry, and be paired with light wheels, the combination of which may be more bum-clenchy on a descent.

I was thinking geometry might be a contributor, in addition to rider error to sketchy-ness on a fast decent. Like others here I've ridden a smorgesbord of frames in different materials and by different manufacturers and never had a problem going downhill. Gone carbon myself - light, direct, fast and comfortable. Can't say I'll be rushing back to another frame material soon. [although a nice Enigma Ti bike....]

LDB

It seems rather conclusive that the carbon doesn't affect the descending.
not for those who replied anyway. So what i'm hearing is that cabon is in fact better and that I should buy a lovely new carbon bike?!

I do think in general though that good fast descending is quite difficult, and takes a lot of skill, especially if you are trying to keep to the left side of the road. I’ve had many a hairy moment where I was glad there wasn’t a car coming in the opposite direction.