deacon mark

I have seen a Dimensions Stem in a 110 mm-35 degree angle and they specifically say that it is not for a full Carbon Fiber Steering Tube. I have found a few others but not many around in that length and angle. Is there something with a higher rise angle that CF steering tubes cannot take? I cannot find anything as such so wonder of anyone else is running one on their road bike and if that is generally safe.

I built a bike up from a 56cm frame I found great used Habanero Ti. I ride a Habanero now in a 58 so not much difference but with tweaking the stem up I pretty much can get them to same riding position. Right now I have a short 80mm with about a 30 degree rise. I road it 45 miles today no issues but another stem would stretch me out better and a bit higher. I am not sure how much is will raise but anything is ok. Any place to calculate the on the internet.

tyrion

Maybe a carbon stem would work on a carbon steerer tube:

https://www.ebay.com/itm/174933700024

The problem is no major manufacturer seems to make them (carbon high rise stem), it's all no-name stuff on ebay and aliexpress. Not sure I'd trust them for a critical component like a stem.

Crankycrank

I don't know why Dimension is issuing that warning. As far as angle goes I don't see any problem as long as you're not clamping it on a steerer tube that spaced is well above the headset. Plenty of Gorilla strength riders could put massive leverage on any near horizontal stem so I'm guessing there is something in their clamp design not safe on CF steerers. Search out another reputable brand. Stem calculator.........Stem Comparison Tool | yojimg.net

alcjphil

It is all about leverage. The higher the handlebar is above the top of the steer tube the more leverage there is while the rider puts out maximum effort. Those recommendations may well be conservative, but there is a reason for them

Crankycrank

That may be their reasoning but a strong sprinter with a 130mm/-7 degree stem will be putting out way more leverage than the average cyclist with a 110mm/35 deg setup.

shelbyfv

Something like the Surly Truck Stop bar would give you 30mm of rise w/o having to use a sketchy stem. Truck Stop

alcjphil

You are correct, but sprinters at that level usually don't keep their bikes all that long. I have a friend whose nickname is "2 HP" He doesn't usually keep any bike more than a year or two

Lombard

I run a 120mm 40 degree stem on my road bike with a carbon steerer. The bike has over 16K miles on it with this build. I haven't died a fiery death yet. It's a Bontrager stem. I wouldn't trust an off-brand though.

I believe as long as you adhere to the specified maximum number of spacers under the stem that the fork manufacture recommends, you will be fine. This is usually around 30-40mm. Be sure to use at least one spacer above the stem as well.

Camilo

Boy, I'd ask the fork manufacturer, not the stem manufacturer. Wonder what they say?

Lombard

Good point.

delbiker1 

I have an aluminum 35 degree stem, 100mm length, mounted on a Lemond Tourmalet with a Profile 1 inch carbon steer tube. The handle bar is a Ritchey Beacon. I am a pretty light rider, 150-55 lbs., and I do not put a whole lot of torque on the set up. I have no qualms riding it.

oldbobcat

Dimension makes very nice components for price-point applications, not high performance.Whenever a manufacturer says don't do something, I take their word for it. Maybe it's the clamping design, maybe its the machining of the ID, maybe it's the gooseneck angle, or maybe they just don't want the liability. I'm having difficulty locating a 35-degree stem that is rated for carbon. Bontrager's alloy Elite stem is rated for carbon and available in 17 degrees.

79pmooney

The bike's a ti Habanero. Ti bikes do just fine with steel forks. Steel forks have steel steerers. Steel steerers care little about stem details.

I know this isn't going to change any minds re: their love of CF forks on ti bikes. I had the bike I rode today built with a steel fork 15 years ago simply because I did one quick ride on a steel forked Merlin ~1990 and thought "this is it!" as I was riding. (That and I've had a non-steel fork fail. So I stick to good old steel.) I spent a lot of the year waiting for that ti bike wondering if I was wrong sticking to steel. First ride cured that thought. Three years later I had a second ti bike made, again with a steel fork. 40k miles on the two and I would change anything about the forks.

My theory on why steel forks go so well with ti bikes - we all know that ti has "the ride". And the engineer types know that ti has half the modulus of elasticity of steel, ie it is twice as flexible for the same shape and size. Also, everywhere on the bike diamond, the tubes are supported at both ends. That support stiffens them a lot. But forks are cantilevers. Cantilevers bend far more. Well that twice as stiff steel there seems to make a sweet match for the rest of ti bike, keeping the ti feel but being stiff enough for the job.

Lombard

Most likely they have a law department who weighs liability risks when they decide on these guidelines. They know that somewhere there will be some 300 lb rider who will be using their product who might have a catastrophic event and then try to sue.

oldbobcat

Just the same, I'll pass on testing your theory.