Advice on steerer tube length.

[ishaw]

I am finally finishing off my first modern build in many years and have a new set of Reba rlt forks fitted to the frame via a lovely hope headset.

My dilemma is that I'm not sure how to discern the best steerer tube length, especially as I'm running risers which is new territory for me, but desirable due to various neck aches and pains I generally suffer from.

I don't want to cut down the steerer and find I've not left enough, but with the steerer at its current length, it's not really rideable without a substantial amount of spacers.

Is there a general formula for this or will it be trial and error? Im not sure ive ever been sure of how to figure this out, and would expect a lot of riding to get this right (something i dont get the opportunity to do). I'd like to get it close and fiddle with spacers if I can. Anyone got any pearls of wisdom?

 

[FluffyChicken]

buy a but load of spacers, you can get plastic one by FSA for not a lot of money. rack them up and ride at full length.
Do it a few times then drop it to the bottom, ride like that for a while.

then guestimate where you would like it, a bit like stem length.

But really it shouldn't normally be anything more than say 25mm at the most, since you should fit a better stem for looks. The headtube is that length for a reason.


Trail and iteration unfortunately.



Otherwise it looks like this. i.e. bloody ridiculous and whoever did this should be shot.

 

[ishaw]

Thanks for the info, I guess it will be trial and error. The main thing for me is that I know what I like reto wise with flat bars and my usual stem length and rise, but with risers and a slightly shorter stem, I'm a little out of my comfort zone (and I really want to create a comfort zone). I have to confess, at the moment the spacer stack on my build looks a bit like the one pictured, and adding to my dilemma is a set of 120mm forks and I'm used to way less in the travel department.

Are there any rules of thumb, do's and don'ts for want of a better phrase, aside from the picture (out of interest, aside from the colours is it that bad??).

I was hoping to finish it off tonight but hit a snag or two anyway (I don't have enough gear cable outer to cable it up, and for some reason the front mech is very, very close to the rear wheel. Will post that a bit later).

 

[coomber]

I had this on my park wood, new forks blah blah

I tried combos "dry" but mocked up then left five millimetres or so above where stem was to go.

This looks ok and is very practical too.

 

[FluffyChicken]

Re:

Not that I would know the owner of aid hiddious setup above, but allegedly, bloke down pub told me, it extremely comfy at least for the 10 to 20 mile rides it goes on. Even more so for slow bimbling rides with little kids.

It was setup as it a long MAG SL steerer and the Syncros stem cannot stack spacers above and the star but is where the cut would need to be. Apparently the ermm chap <caught> had a few mins to put it together before the ride. And not got around to sorting it.

Go for it, cut only when you are happy.

 

[mattr]

Rule of thumb is a max of 1.5x steerer diameter of spacers under the stem. So between about 30 and 45mm. More than that and you start getting into problems with keeping the headset adjusted (lots of tolerance stack to account for and some flex) or with light weight steerers you might snap it. With a heavy weight steerer you might be able to get away with more
I'd just get a "set" of spacers, some manufacturers do them, 10, 8, 5, 3 or similar, then a couple of 10s to finish off the stack, then you can play with position endlessly.

 

[highlandsflyer]

You are wise not to cut before thinking long and hard.

I like to leave a least a couple of spacers in the mix in case I want to swap the fork over or change the stem, headset, etc.

There are plenty of step by step walkthroughs on the internet.

Any pics of your build?

 

[The History Man]

Nothing wrong with a few spacers. As another back sufferer I find that grip roughly on eyeline with front axle works for me regardless of bar type. Your hopefully not jumping off anything so flex/failing shouldn't be an issue.

So kill me now.

 

[ishaw]

Thanks. I'll add a pic of it as it stands before cutting. I've got about 35mm of hope spacers below the stem and a tiny one above. I can't see me needing any more than that so should be safe to cut, but measure twice, cut once is repeating in my head so want to make sure I don't make a hash of things (and no, I won't be using a hacksaw, but a pipe cutter).

 

[dyna-ti]

You could use an old stem as a saw guide. Just make sure its 0 rise and is square to the steerer.
MAKE THE CUT ON THE WASTE SIDE(the bit that falls off onto the floor)

My advice is to go 20mm min longer than you need and put some spacers over it then the top cap. Spacer placement arent set in stone that they need to be underneath the stem.
The steerer that came on my new manitou's was 260mm and i needed about 240mm. Shame to cut it so just capped the top and its been like that for a couple of years without any problems presenting itself
My set up is coming out the headtube CK- 40mm of spacers - Hope stem further 10mm spacers and the ck topcap. Ive recently moved a 5mm spacer from on top to underneath to lift it a little :? It did make a comfort difference to me puir old back
Other than the handy adjustment you get ,should you change frames and the headtube turns out to be longer it would save you looking for another fork.