Carbon Frame Bike on Turbo Trainer?

When drugs don't work: training and health tips!
gooner71
Posts: 15
Joined: Thu Jun 25, 2009 09:13 am

Carbon Frame Bike on Turbo Trainer?

Postby gooner71 » Thu Nov 12, 2009 11:08 am

Hi guys,

Would I be putting a carbon frame under stress on a turbo trainer?

I've never had a turbo trainer before and only have the one road bike so a bit stuck if this is a bad idea.

Thanks
Simon

User avatar
Wooliferkins
Posts: 2039
Joined: Thu Dec 30, 2004 11:48 am
Contact:

Postby Wooliferkins » Thu Nov 12, 2009 11:15 am

Slightly different stress yes. As your wheels on the turbo are fixed laterally the sideways moment of pedalling will be absorbed by the bike as opposed to turned into rocking of the bike (think side to side when honking) I would be surprised if it was quickly terminal but I would look for a hack frame for the turbo.
Neil
Help I'm Being Oppressed

ut_och_cykla
Posts: 1579
Joined: Wed Jul 18, 2007 13:46 pm

Postby ut_och_cykla » Thu Nov 12, 2009 11:59 am

The turbo trainer frame takes up the forces involved. A German bike mag did loads of tests (last year?) and concluded that your bike was more at risk doing mad bad sprints on the road than hard workouts on teh trianer. But if you're worried contact teh bike's manufacturer and ask them? :)

gooner71
Posts: 15
Joined: Thu Jun 25, 2009 09:13 am

Postby gooner71 » Thu Nov 12, 2009 12:23 pm

Thanks guys - this question was posed mostly to find out whether I should be worried... lol. I might email Trek but what's the chance of a sensible answer on a 6 year old carbon frame?

tri-sexual
Posts: 673
Joined: Sat Mar 21, 2009 14:14 pm

Postby tri-sexual » Fri Nov 27, 2009 13:26 pm

i use one, no problems
all the pros use turbos to warm up before races and tt

matterai
Posts: 161
Joined: Fri Jun 19, 2009 07:25 am

Postby matterai » Fri Nov 27, 2009 13:40 pm

tri-sexual wrote:all the pros use turbos to warm up before races and tt


I doubt they pay for their carbon bikes though :wink:

User avatar
GavH
Posts: 932
Joined: Thu Dec 04, 2008 21:20 pm

Postby GavH » Sat Dec 05, 2009 16:21 pm

Sorry for the bump, but I'd be interested to hear from anyone who has had a CF frame fail on them due to use on a turbo. I've just been offered a very good price on my Carrera Virtuoso from a work colleague and this means I'll only have the Bianchi for both road and indoor use.

User avatar
lloydy75
Posts: 71
Joined: Mon Nov 10, 2003 15:17 pm

Postby lloydy75 » Sat Dec 05, 2009 16:23 pm

I've got a Tacx Flow with over 5000 miles logged and only used carbon frame road and TT bikes on it with no problems.

User avatar
JohnnyAllez
Posts: 780
Joined: Sun Dec 07, 2008 17:36 pm

Postby JohnnyAllez » Sat Dec 05, 2009 16:37 pm

Other option is a set of rollers with added resistance unit ? Lots more fun staying upright :)
Jens says "Shut up legs !! "

Specialized S-Works SaxoBank SL4 Tarmac Di2

chrisw12
Posts: 1151
Joined: Sat Jul 07, 2007 08:20 am

Postby chrisw12 » Sat Dec 05, 2009 22:39 pm

Don't know the answer but I stay sensible on my turbo in that I try to keep things smooth and certainly don't stand up and certainly don't do power sprints.

I would have though that standing and rocking could cause damage due to the 'twisting force' you put in, can anyone confirm or deny this with some physics?

tri-sexual
Posts: 673
Joined: Sat Mar 21, 2009 14:14 pm

Postby tri-sexual » Sun Dec 06, 2009 04:46 am

i dont know why people are so scared of using carbon frames in " stress " situations
i have seen quality carbon frames undergo deflection tests you would not believe to be possible.
a carbon frame would be rigged up to a test machine with hydraulic rams continuously twisting the frame, the amount of force applied would be many times humanly possible and the amount of deflection is enormous, this sort of deflection would destroy a metal frame (alu, steel or Ti) in minutes but a good frame can be engineered to take these lateral forces and i have been informed that the frame would still be structurally sound even if the test is ran for over a year
i must stress that quality carbon frames were used so cant say for if this is true for all frames (dont blame me if your frame falls to bits)
there are videos on youtube where a carbon frame is crushed in a heavy workshop vice, the carbon can take alot of abuse before it delaminates and fails, a similar test is done on a aluminium frame from the same manufacturer and once the alu frame is crushed can never regain its original shape (cannondale)
other manufacturers do impact test where a heavy metal sphere is dropped from several feet onto a carbon frame, a good standard frame can withstand the damage but a super lightweight frame from the same manufacturer will be destroyed in the same test (these are the frames used in the mountain sections of the TdF)
commencal started doing carbon mtb frames this year, they say that its for strength rather than weight saving
cannondale scalple's rear stay is carbon and is designed to flex many thousands of times over a single bike ride and they seem to be structurally sound even after many years of use.
carbon frames can be engineered to be super stiff where required (aroung BB and head tube) and "flexible" in others (for comfort) in forks, seat stays, seat tubes towards the top, where some compliance qualities adds to the plushness of the ride.
not all carbon frames are created equal but a well deigned and engineered one can equal or exceed the specifications of any other frame material (excluding acid test, burn test, salt water tests which in many cases are pretty pointless anyway)
carbon and turbo trainers, i use mine even though i have bikes of other materials to choose from

chrisw12
Posts: 1151
Joined: Sat Jul 07, 2007 08:20 am

Postby chrisw12 » Sun Dec 06, 2009 09:03 am

I agree with what you're saying that cf as strong as anything and if well designed then no problems...

but what about my question as regards standing efforts? What I mean is, if you clamp the rear end then pull/push the bike over to the side (like you would when standing) then surely there will come a deflection point where the material will snap? Ok, you might not be able to generate enough force but doing this over and over, will it fatigue the frame?

I'm thinking for example when you snap the end of the opening part of a can, one part is fixed, but when you move the other end back and fore it eventually snaps.

I can't see how/why a frame would be designed for this as it's a totally different lateral force than the bike will experience on the road. When you 'stand' on the road the bottom of the tyre is the pivot point not the frame.

I ask this question about all frame materials not just cf by the way.

tri-sexual
Posts: 673
Joined: Sat Mar 21, 2009 14:14 pm

Postby tri-sexual » Sun Dec 06, 2009 12:07 pm

all frame materials has a modulus of elasticity, simply put it will "give" to some degree (even glass will bend to some degree before it breaks)
fatigue occurs when a material fails after repeated bends and the structural integrity of the material fails
as i mentioned on an earlier post, seen a carbon frame tested where the front tube and the rear end is fixed to a test rig and the bottom bracket is subjected to forces where the bottom barcket is deflected laterally (by probably 150mm if not more) from side to side and the frame survived, the test engineer claimed that the frame can be subjected to such forces for a year without breaking
pro cyclists use cf frames on turbos (they probably dont buy their own), i use cf on turbos (i got choice of other frame materials to choose from)
i have broken a few frames (in all different materials) throughout the years -though most were due to impact damage, not saying cf will not break but a well designed and manufactured one can be much stronger than people think (some super lightweight frames will be weaker because less carbon plys and resin would be used)
personally i think they're fine for turbos-has anyone broken a carbon frame on a turbo? (not inc ones previously damaged from impacts/crashes)
for those who dont trust carbon on turbos, buy a cheap bike and use that instead- problem solved

User avatar
GavH
Posts: 932
Joined: Thu Dec 04, 2008 21:20 pm

Postby GavH » Sun Dec 06, 2009 15:08 pm

tri-sexual wrote:all frame materials has a modulus of elasticity, simply put it will "give" to some degree (even glass will bend to some degree before it breaks)
fatigue occurs when a material fails after repeated bends and the structural integrity of the material fails
as i mentioned on an earlier post, seen a carbon frame tested where the front tube and the rear end is fixed to a test rig and the bottom bracket is subjected to forces where the bottom barcket is deflected laterally (by probably 150mm if not more) from side to side and the frame survived, the test engineer claimed that the frame can be subjected to such forces for a year without breaking
pro cyclists use cf frames on turbos (they probably dont buy their own), i use cf on turbos (i got choice of other frame materials to choose from)
i have broken a few frames (in all different materials) throughout the years -though most were due to impact damage, not saying cf will not break but a well designed and manufactured one can be much stronger than people think (some super lightweight frames will be weaker because less carbon plys and resin would be used)
personally i think they're fine for turbos-has anyone broken a carbon frame on a turbo? (not inc ones previously damaged from impacts/crashes)
for those who dont trust carbon on turbos, buy a cheap bike and use that instead- problem solved


A good post and one that asks the million dollar question! Plenty of folks saying don't use one, but no-one has actually seen a frame break from use on a turbo, have they?

User avatar
Monty Dog
Posts: 20382
Joined: Thu Dec 14, 2006 14:31 pm

Postby Monty Dog » Sun Dec 06, 2009 17:16 pm

From someone whose been on numerous cycling fora over the year, I have never seen anyone break a frame on a turbo - the question gets asked with regularity every winter.
What you will find is that many manufacturers say that turbo use invalidates any warranty - the same with using a roofrack too
Make mine an Italian, with Campagnolo on the side..

Team Banana Spokesman
Posts: 446
Joined: Tue Jun 09, 2009 22:51 pm

Postby Team Banana Spokesman » Sun Dec 06, 2009 18:25 pm

I would be worried about non-carbon bikes more because theyre weaker. if youve got carbon you should be able to push it harder than any other bike before permanently killing it.

User avatar
GavH
Posts: 932
Joined: Thu Dec 04, 2008 21:20 pm

Postby GavH » Sun Dec 06, 2009 18:26 pm

I wonder if (BIG IF it seems) you did break the frame whilst on the turbo, whether or not your home contents insurance would cover it under Accidental Damage?

tri-sexual
Posts: 673
Joined: Sat Mar 21, 2009 14:14 pm

Postby tri-sexual » Mon Dec 07, 2009 00:50 am

i didnt know bike manufacturers didnt honour frame warranties if used on a turbo :shock:
if i did break any of my carbon frames on the turbo i am sure that i will be totally honest when asking for a replacement by telling them that it broke on a turbo trainer rather than through "normal" road use :wink:

The Mechanic
Posts: 1264
Joined: Fri May 28, 2004 13:26 pm

Re: Carbon Frame Bike on Turbo Trainer?

Postby The Mechanic » Mon Oct 21, 2013 14:16 pm

I have recently purchased a Felt Z4 full carbon bike. This is my first carbon frame and noted that the bike came with numerous stickers warning about just about everything, including "do not remove the sticker" warnings. It is interesting to note that one of the stickers said words to the effect that you should not clamp any part of the frame in a work stand, turbo trainer, roof rack etc.
I have only two things to say to that; Bo***cks

User avatar
monkimark
Posts: 514
Joined: Wed Oct 03, 2012 16:38 pm

Re: Carbon Frame Bike on Turbo Trainer?

Postby monkimark » Mon Oct 21, 2013 14:23 pm

My turbo clamps the skewer, not the frame.


Return to “Training, Fitness and Health”

Who is online

Users browsing this forum: No registered users and 2 guests