Road Bike, Cycling Forums banner
1 - 19 of 19 Posts

·
Registered
Joined
·
1,846 Posts
There's no technical reason to leave a spacer above the stem. The suggestion is probably made because when cutting forks it's better to err long than short, since an overly shortened fork cannot be recut longer. (measure twice, cut once)

Another benefit of a bit of excess fork length is that if you should later decide to raise your stem, you have the option of transferring the spacer to below it.
 

·
Registered
Joined
·
10,160 Posts
not so...

FBinNY said:
There's no technical reason to leave a spacer above the stem. The suggestion is probably made because when cutting forks it's better to err long than short, since an overly shortened fork cannot be recut longer. (measure twice, cut once)

Another benefit of a bit of excess fork length is that if you should later decide to raise your stem, you have the option of transferring the spacer to below it.

You're full of misinformation. A lot of fork brands specify either a 5 or 10mm spacer to be placed above the stem for a very good reason. It greatly reduces the chance of cracking the top of the head tube. Most stem these days have a 2-bolt steering tube clamp, with the top bolt very close to the sop of the stem. A lot of people who leave the steering tube 2-3mm below the top of the stem have cracked the steering tube. Some of the problem is user error from overtightening, of course. If I don't have a spacer above the stem, I deliberately tighten the lower bolt more and the top bolt less, to avoid any problem.

LOOK frames, for example come with a conical, "top specific" 5mm spacer, just for the purpose of placing above the stem.
 

·
Two wheels=freedom!
Joined
·
708 Posts
If you use a spacer above the stem, you can cut the steerer so that the stem has a larger contact area on the steerer. A steerer that protrudes above the stem results in a more even clamping force. A steerer that ends below the top of the stem leaves a portion of the stem clamping surface un-supported and can result in uneven clamping forces and potential damage. This is especially true when carbon steerers and stems are used together.
 

·
Registered
Joined
·
1,846 Posts
I stand by what I originally said.

Some fork manufacturers do suggest added fork height above the stem, especially with carbon steerers, (with spacers above) to buy a degree of protection against overtightening, or the use of poorly quality stems. But it isn't necessary if one take the simple approach of using a quality stem and not overtightening it.
You can take a counter measures against shoddy work, or you can simply do the job right in the first place.
 

·
Registered
Joined
·
10,160 Posts
sure...

Even when you're dead wrong you won't admit it. You said there is no technical reason for the spacer, but there certainly is.

Manufacturers can't assume that every consumer has the experience to know not to apply too much force to that top stem bolt, so they take the safe route and recommend the spacer.

As I said, I don't always use a top spacer either, but I've read enough posts on several forums with pictures showing cracked steering tubes to know that it can be done.

You need to include more detailed info so the OP can decide whether to use the spacer or not. People wouldn't ask these questions if they had been wrenching on bikes for 25 years, like I have and knew the answers.
 

·
Banned
Joined
·
14,484 Posts
C-40 said:
Even when you're dead wrong you won't admit it. You said there is no technical reason for the spacer, but there certainly is.

Manufacturers can't assume that every consumer has the experience to know not to apply too much force to that top stem bolt, so they take the safe route and recommend the spacer.

As I said, I don't always use a top spacer either, but I've read enough posts on several forums with pictures showing cracked steering tube to know that it can be done.

You need to include more detailed info so the OP can decide whether to use the spacer or not. People wouldn't ask these questions if they had been wrenching on bikes for 25 years, like I have and knew the answers.
Thank GAWD I have sense enough to use quill stems.
 

·
Registered
Joined
·
400 Posts
I've started to do this on all my bikes. I think C40 make a great point, one I hadn't considered. I do it because I like building bikes, riding them for a while, and trying something new. By keeping more steerer tube length it improves resale.
 

·
Registered
Joined
·
3,394 Posts
And of course, some fork manufacturers specify (very clearly) that the top cap should be flush with the stem clamp.

Never base your fork / steer tube installation on advice and good ideas you find in forums like this, you should check the specs for your particular fork.
 

·
Registered
Joined
·
514 Posts
not necessary if . . .

framed said:
The Ritchey website states "It is preferred to leave excess length on the steerer tube and add a spacer above the stem." Would others recommend doing this? Thanks.

http://www.ritcheylogic.com/media/File/1003_CFFORKownersmanual041708.pdf
I don't use a spacer above the stem on my carbon steerer fork (I'm tall, and prefer highest stem position doable), but use two other Ritchey-designed products to minimize the risk of steerer damage:

  • Ritchey WCS stem (aluminum): awsome stem with bilateral steer tube cut/clamp.

  • Ritchey Torquey (I know some experts don't need these) to make sure I don't over-torque the stem bolts.
Aestetically, I do like the look of the topcap resting on the stem.
 

·
Registered
Joined
·
3,255 Posts
"Ritchey Torquey (I know some experts don't need these) to make sure I don't over-torque the stem bolts."

Great tool. I use one of those too and only use WCS and 4 Axis Ritchey stems. Some of my bikes have a spacer on top, some not, but most ended up with a 2-5mm spacer.
 

·
Unsafe at Any Speed
Joined
·
456 Posts
Just do it and don't argue.

Any steerer which doesn't reach the top of the stem, risks damage from the internal edge where the stem horizontal tube joins the vertical (clamping) section.

It beats me why the clamping section of the stem is never an entire sleeve. The hole saves a precious 2 grams I suppose.

And the top edge, above the hole, is generally a miserable 1mm or so tall. Just the thing for wearing a ridge into a carbon steerer.
 

·
Old, slow, and fat.
Joined
·
3,897 Posts
Had the misfortune of hearing some carbon go crunch ONCE and figgered Its a good thing to have the clamp below the top of the steerer tube. I've been doing it since.

M
 

·
So. Calif.
Joined
·
2,800 Posts
I opted for a spacer above stem (CF steerer tube) for the reasons cited above.
Right now it's 10mm above. Below stem, a 20mm cone and 10mm spacer.
I'll adjust the spacer stack gradually, but I'll always leave at least 5mm above.
.
 

·
Registered
Joined
·
134 Posts
Discussion Starter · #15 ·
Many thanks for the replies. I think I'll go with 10mm pictured above because: 1) it leaves room for adjustment, 2) it reduces the chance of cracking the steerer tube, and 3) it looks good.
 

·
Registered
Joined
·
3,394 Posts
So I repeat to those of you who insist that the steer tube should extend above the stem clamp: do you recommend this even for forks that have specific instructions to cut the steer tube 2-3 mm BELOW the top of the stem clamp so that the top cap is flush?

I just can't believe people who think their opinion is better than the fork manufacturer's specifications and instructions.

I repeat: install your fork the way the manufacturer instructs.
 

·
Old, slow, and fat.
Joined
·
3,897 Posts
I always leave things long. Easier to cut it shorter later than it is to stretch it. If that means leaving spacers above the stem, it means leaving spacers above the stem.

M
 

·
So. Calif.
Joined
·
2,800 Posts
Specialized, for exmpl, recommends having the carbon steerer reinforced by the expander plug, in the region where the stem is clamped. As long as the plug extension is equal to, or beyond, both ends of the stem, shouldn't matter if there is an optional spacer above stem. See diagram below.

My 3T stem is 40mm high, the plug is 48mm long, so a 5 or 10mm spacer above stem is easily accomodated.
.
 

·
Registered
Joined
·
514 Posts
tom_h said:
Specialized, for exmpl, recommends having the carbon steerer reinforced by the expander plug, in the region where the stem is clamped. As long as the plug extension is equal to, or beyond, both ends of the stem, shouldn't matter if there is an optional spacer above stem. See diagram below.

My 3T stem is 40mm high, the plug is 48mm long, so a 5 or 10mm spacer above stem is easily accomodated.
.
. . . however, the "right" diagram does not show any spacers above the stem. Not challenging your statement, however, that fewer/smaller spacers above the stem do not violate Specialized's instruction.

I see the wisdome of following the manufacturer's instruction for warranty purposes, but it seem only "persuasive" authority beyond that. In othe words, so long as you're dealing with an apples-to-apples instruction (e.g., for installing a carbon, vs. aluminum steerer), then I don't see much reason to think that Specialized or Trek or Easton or Park Tool have greater/better kowledge than others. Of course, there may be exceptions. For example, Look markets a carbon fork with a built-in threaded plug of some sort for pre-loading the bearings during stem installation. I'd for sure want to follow THOSE product-specific instructions . . . .
 
1 - 19 of 19 Posts
Top