[chas0039]

Is there a max height for mounting the threadless stem above the headset?

 

[unit]

Is there a max height for mounting the threadless stem above the headset?

Assuming that you have the right amount of spacers and steerer length to accommodate the stem/fork interface in accordance with the stem and fork manufacturers recommendations, I know of no published limit.

Obviously the higher you go the more leverage you are applying to the steerer, so a more ideal situation might be to get a frame that better suits your needs/dimensions so that you do not need to run a big spacer stack.

How high are you planning on running your stem exactly? What is the nature of the steerer tube (material, make, model). How heavy are you, and what sort of surfaces to you ride?

 

[ms6073]

The answer can also depend on whether or not the fork has a carbon steerer tube as some of the manufacturers have started to indicate that more than 4-5cm of stack height under the stem is not recommended. Realizing that many of us have physiological limitations and many who read this might reply that they are riding beyond the recommended stack height, I would also add that for normal circumstances, a stack height greater than 4-5cm might indicate a new for a frame with a different gemometry - compact/sloping top tube, or even traditional geometry frames that have a taller head tube to help reduce the stack height.

 

[C-40]

yes...

If the steerer is carbon, you're usually limited to 3-4cm, with steel or aluminum there may be no published limit, but even 4cm looks pretty silly. Use a higher stem angle. If a +10 and 3cm of spacer doesn't do it, then the frame's too small.

 

[chas0039]

Thanks for all the input. I had not read of any limit, but someone in passing at a bike shop was very specific about a particular measurement in a discussion I overheard and I was curious as to anything I might have missed.

The steering tube is steel and I am not going to any extreme height, just short of 4cms. I ride roads and weigh 178. Both forks are Reynolds Carbon and the stems are Oval and FSA.

I really appreciate the feedback. I would hate to break something because I missed the fine print.

 

[dookie]

reynolds says no more than 1" of spacers on a 1" steerer. 1.125" can take a bit more, but i don't know the exact value. don't chance it...

 

[the Inbred]

i had a customer today request that i leave 80mm worth of steerer on the TT bike we were building up for. the guy who sold him the bike had recommended that. i finally talked him down to 60, as well as signing a release waiver. i'm still afraid to send it out with that.

 

[cyclust]

Obviously the rider's riding style must be considered. If you are a heavy rider and ride out of the saddle a lot, then more care must be taken, as riding out of the saddle puts a lot more stress on the front end of a bike. Also sharp cornering at high speeds would stress the headtube more. But for a casual recreational cyclist who never stresses the bike too hard, I would think would be safer with more spacers under the stem. You could also install a headtube extender rather than run a large number of spacers. I know that specialized sells one on their website, and cannondale equips their 08' synapse models with one, though I don't know if they sell it seperately.

 

[ukiahb]

QBP sells one too under the Dimension label, any bike shop could order it...just added one to my cruiser but cut the top off as the bars are high enough with the stem low on the extender....this is for a 1 1/8 steel fork so it seems safe enough to me...FWIW a Velox bar plug fits well in the top of the extender, the original cap is threaded so I could not use it after cutting.