Road Bike, Cycling Forums banner
1 - 18 of 18 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter · #1 ·
Hi all- I have been enjoying RBR for about a year. This is the same time since I purchased my first road bike, a 2007 Felt F3. I took the bike for some minor tuning to my local bike shop today. I questioned one of the owners that under power, the headset portion of the frame slightly flexes from left to right. I thought that it was normal for a carbon frame to flex. He said that before I was measured for the frame, they should have asked me for my weight (I am 5'10" & weigh 195 lbs- I have a large frame & medium muscle build) I was told that if I kept riding this way that I might cause "catastrophic failure" of the frame. This is a big concern for me since I am a speed freak & if the frame fails on one of my 45mph plus power descends- its going to hurt! :eek: The bike shop owner further suggested that a Titanium or aluminum frame will be the best fit for me.

I would like some input from you guys about this situation- should I really be that concerned about the frame collapsing on me because of my weight/power?
Is Titanium the way to go?

thanks!
 

·
Registered
Joined
·
863 Posts
Well, I do love Ti, but your shop dude sounds full of it. The bike won't spontaneously combust, thought it might not be as stiff as you would like. If you enjoy the ride now, don't worry about it. Once you've worn that frame out, you might mention frame stiffness as more of a priority when your shopping for your next one.
 

·
Carbon Fiber = Explode!
Joined
·
3,955 Posts
Kaboom! CF baby!
 

·
Registered
Joined
·
2 Posts
Last Fall/WInter, I decided to buy a new bike. A majority of my friends ride Litespeeds. They swear that they will last forever. After careful consideration, I bought a carbon Orbea Orca. Simply because it makes me happy. We are not guaranteed anything in this lifetime. So, why not be happy with carbon. Others may play the "fear," card. If you are happy with your bike, ignore the detractors.:)
 

·
Gruntled
Joined
·
3,775 Posts
no way

I'm sorry, but whoever told you this is FOS. Find another shop. Magnus Backstedt & Thor Hushovd ride carbon frames and don't break them. Those are big, strong guys and two of the most powerful sprinters in pro cycling.

If you just want a stiffer ride that's one thing, but there's no way a normal human is strong enough to break a carbon frame just by pedaling.
 

·
Registered
Joined
·
464 Posts
agree with others, the likelihood of you frame coming apart on you is next to nil and you would be wise to never set foot in that store again - you were being conned.

As for the flex issue, are you sure it is in the head tube, or is it the fork as you can always buy a stiffer fork if you are happy with the rest of the frame (i.e., stiffness in the BB area).

Also, if you are new to riding, suggest you change your riding style learning to ride more smoothly and in the saddle.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #7 ·
Thanks for your input guys- I also wrote to Felt but I have not received anything yet. Will post their answer as soon as I get it. I am going to keep the bike till I feel that I have surpassed its performance (that's some time from now). I honestly dont feel like I am going to break the frame.

Johnnysmooth- I have been concentrating on keeping my knees in line (close to the frame)keeping my uppper body somewhat loose and not creeping forward on the saddle when I am pedaling hard- The frame seems to move less & I have also noticed that my knees do not hurt after my ride with this technique.

I would believe that a stiffer frame/fork will translate to more pedaling power being tranfered to the pavement- is this true to some extent?
 

·
A wheelist
Joined
·
11,689 Posts
Superma said:
I would believe that a stiffer frame/fork will translate to more pedaling power being tranfered to the pavement- is this true to some extent?
Yes maybe. But everything has a cost. Maybe a stiffer frame beats you up more, tires you out so that, let's say in a road race sprint finish, you're just not there to contest the sprint at the end and take advantage at that stiffness.

Arguably, one of the best roadman-sprinters of all time - Sean Kelly in the '70s & '80s - rode just about all of his career on one of the flexiest frames the world has ever known, the Vitus 979 aluminum frame.

I had one and I'm not even shadow of Sean's power and I found that frame soft and flexy. It sure as heck didn't stop Kelly winning sprints.
 

·
Registered
Joined
·
484 Posts
Your headset is not properly installed. If you lift the front portion your bike up by holding the top tube, the headset should not drop or be there any slop. However, there needs to be a very, very small gap between headset and head tube otherwise the headset is restricted from rotating about the head tube freely. I am suspecting you have a loose headset. Regarding to power sprints, it's usually the front fork that flexes the most.

You are correct, the stiffer the bike the more efficient the power transfer is from your pedeals to the wheels. Carbon is very stiff and the high end models are usually much stiffer than the aluminum ones. Yes, it's a matter of material but also how big the diameter of the tubes are also. The bigger the downtube, the stiffer the bike is. It's much harder to bend a big diameter pipe versus a thin diameter pipe of the small length. That's why steel frames with their thinner tubes are a much more comfortable ride but is more flexible.
 

·
Registered
Joined
·
507 Posts
If you want stiff go to eBay or Craigslist and get an old Cannondale 2.8. That transfers power to the pavement bigtime and rides like a sawhorse. I'd stay with whatever good CF framed bike you have, but I'd find another shop. I am new to CF myself and really like it.
 

·
Banned
Joined
·
3,262 Posts
Not really

tjjm36m3 said:
You are correct, the stiffer the bike the more efficient the power transfer is from your pedeals to the wheels. Carbon is very stiff and the high end models are usually much stiffer than the aluminum ones. Yes, it's a matter of material but also how big the diameter of the tubes are also. The bigger the downtube, the stiffer the bike is. It's much harder to bend a big diameter pipe versus a thin diameter pipe of the small length. That's why steel frames with their thinner tubes are a much more comfortable ride but is more flexible.
http://www.bikethink.com/Frameflex.htm

http://www.fitwerx.com/NewFiles/Tech Center/BicycleStiffness.html

http://www.fitwerx.com/NewFiles/Tech Center/MythofMaterials.html

http://www.sheldonbrown.com/frame-materials.html

http://www.rivbike.com/article/bicycle_making/frame_materials

http://www.kirkframeworks.com/Flex.htm
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #12 ·
Thanks all for your input (lookrider- those links are great- lost of good reading) I have decided to take my bike back to the shop where I purchased it & have the owner look at it just in case.

I ride every weekend at Harriman State Park in NY ( http://nysparks.state.ny.us/gmaps/?pId=143 ) check out the terrain map- lots of twisty uphills & downhills(County Highway 106- Cedar Pond Rd.), awesome views (7 Lakes Drive) & even a fresh river waterfall where you can stick your head in! (Arden Valley Rd.) - Anyone near the NY area Interested in riding this awesome park- I am free to ride together as a guide/partner.
 

·
Home Brew User!
Joined
·
2,812 Posts
Superma said:
Hi .... I questioned one of the owners that under power, the headset portion of the frame slightly flexes from left to right. I thought that it was normal for a carbon frame to flex. He said that before I was measured for the frame, they should have asked me for my weight (I am 5'10" & weigh 195 lbs- I have a large frame & medium muscle build) I was told that if I kept riding this way that I might cause "catastrophic failure" of the frame. ......
He sounds like a complete idiot!

Disregard anything he says!
 

·
Lemur-ing
Joined
·
19,208 Posts
Tom Boonen and Fabian Cancellera put out more power than almost anyone at times and have no problems. Find a new shop. Really.
 
1 - 18 of 18 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top