|Is it ok to have 40cm (1.5") spacer for 1inch dia carbon||pnda|
May 11, 2003 11:55 PM
|fiber steerer fork? I've heard someone said the maximum is 1". Why is that? I like the extra height for comfort reason. Is there a danger if I exceed the 1"? Thanks.|
|re: Is it ok to have 40cm (1.5") spacer for 1inch dia carbon||Akirasho|
May 12, 2003 2:10 AM
|... many makers of carbon fiber steerers recommend a limit of 1" (25mm) for a 1" steerer and 1 1/2" (38mm) for a 1 1/8" steerer...
Limits are imposed because of the amount of force that could be applied to specific intersections of the steerer with headset bearings (generally, the upper) and the stem... which might exceed the capacity of the carbon fiber/resin matrix.
These limits are conservative (there are a ton of variables to consider (rider strength, stem length, amount of weight and/or type of force a rider puts on these interfaces, riding style, etc.)), but they are limits nevertheless. Using the product outside these limits may void any warranty/litigation issues.
According to Reynolds literature, you're over the limit for their 1 1/8" carbon fiber steerer let alone a 1"... but I must admit that I run slightly over recommended on a relatively low milage TT bike.
I'm not an engineer, and perhaps someone will be able to offer a better explanation... especially with respect to an added variable of stem angle... that is... what happens if you run a stem angle that would put your bars in essentially the same spot but with less spacers? My guess is that you're still lessening forces at the upper bearing... and this might be a route you need to consider.
Be the bike.
|re: Is it ok to have 40cm (1.5") spacer for 1inch dia carbon||terry b|
May 12, 2003 5:41 AM
|Alpha Q is the only 1" fork I know of that allows 40mm of spacers. The reason they go that high (I think) is because of their unique sleeve insert. Every other one I've installed calls for a max of 25mm at that steerer diameter.
I suppose the risk is you'll snap it off. Who knows if that's true, or whether that 15mm will make any difference at all. It might just be the MFGR being conservative in this litigious atmosphere we've come to live in and I'm sure you'll hear lots of success stories from people exceeding the limit. I however have this thing about following MFGR recommended specs and don't generally violate them.
|re: Is it ok to have 40cm (1.5") spacer for 1inch dia carbon||clintb|
May 12, 2003 6:18 AM
|Believe it or not, Giant recommends no more than 50mm of spacers on my composite TCR 1-1/8 carbon fork. Pretty crazy amount of spacers if you ask me. I called Giant twice just to verify and make sure I didn't hear them wrong the first call.|
|re: Is it ok to have 40cm (1.5") spacer for 1inch dia carbon||tkohn|
May 12, 2003 11:45 AM
|There may be a reason why that I don't know but, why don't you flip your stem or get a positive rise stem and take out some spacers? If you consider what a steerer tube failure crash can look like, I myself would play it safe.|
|I've never heard or read of a failure at the stem||MGS|
May 13, 2003 3:48 PM
|Although there is a max of 1" by many manufacturers, many people routinely exceed the max. If you do a google search, you will find this question asked many times, with the limitations and warranties quoted, but never has a failure at the stem/fork interface been reported.
As a matter of fact, although I am sure someone will report a case, I am unaware of any known or reported carbon fork failure at the stem or headset interface.
So, warnings are often based on the legal concerns, not true science or known/proven limitations.