So I’ve finally replaced my ancient, but comfy road bike. The new one has come with the steerer/handlebars at max height which is higher than my previous from the front axle to stem.

So I’m thinking it will need lowering, but aware there may be slight differences to geo which means that just replicating the same height may not be the way to go?
Ideally I would want to end up with a flat stem/steerer tube as it looks best, but don’t want to cut in error in haste!

Can anyone advise if this is the best way to approach this?

1 – ride with bars at max height
2 – Ride with bars at height of old bike – spacers on top
3 – Longer ride with any required small adjustment up or down – spacers on top
4 – repeat above if required
5 – cut steerer to match

With this being an integrated cabling in the stem/headset and hydro brakes I guess I’m having to disconnect everything to cut the carbon steerer and then re-bleed? Or is their a cheat way to avoid this?

1 – ride with bars at max height
2 – Ride with bars at height of old bike – spacers on top
3 – Longer ride with any required small adjustment up or down – spacers on top
4 – repeat above if required

Yes.

Ideally I would want to end up with a flat stem/steerer tube as it looks best

Who GAS what it looks like – what does it ride best at?

Ideally I would want to end up with a flat stem/steerer tube as it looks best,

I’m past caring about this. My new gravel bike has a huge head tube and a couple of spacers too, but it’s comfy for me and I get out on it more cos it’s comfy. Maybe it’s being in my mid 40’s that has caused me not to care anymore what other people think.

I wonder how many “slammed stems for the sake of fashion” have made people ride less or stop altogether?

No I don’t mean slammed with no spacers just for appearance – just what’s the lowest setting for me but still comfy. When I say flat I mean the steerer is then cut for that height to remove excess above the stem.

Bracketing is almost always the answer to this kind of thing. Try highest and lowest. If you prefer highest then try highest and halfway. If you prefer halfway then try halfway and 3/4 up. If you prefer three quarters up try 3/4 and 5/8 up. Etc.

Front axle to bars is probably not the best measurement either, you want to look at stack heights.

Assuming you have the same BB-saddle height on both bikes, you want to measure the BB height of the old bike and the bar height of the old bike. Subtract BB height from bar height and you have your ‘stack’ (technically stack is BB to upper headset cup, but BB to bar height is closer to what you want to achieve).

Measure the BB height of the new bike and the bar height of the new bike to get the ‘stack’ of the new bike. Adjust as necessary to achieve same stack as old bike.

A simpler way might be to measure ground – saddle and ground – bars, the difference is the bar ‘drop’ and then you can just replicate that across both bikes.

I’d long forgotten the ‘rules’ about stems and spacers, I’ve been riding lots of spacers and a positive rise stem for ages now, I drop it 5mm occasionally, when I remember, but even on a bike with a very tall headtube, slamming a negative stem would give me a massive saddle – bar drop which is just masochistic for long rides.

“ When I say flat I mean the steerer is then cut for that height to remove excess above the stem.”

On a MTB I always leave some steerer above because you never know when something will change what you need.

It’s also worth leaving a small spacer above the stem if the steerer is carbon. Some manufacturers recommend this.

Ok thanks all – will play it conservatively.

I’m slowly fiddling with my new Orbea, set the height to where my old bike was and rode it a bit, seemed fine, so cut a chunk of steerer off (but leaving enough to go back up a bit). Then removed another spacer and tried that, seemed fine. Then winter came so not been riding it. Come spring, will carry on iterating it down till I find my comfort limit and finally get a new position determined.

It’s also worth leaving a small spacer above the stem if the steerer is carbon. Some manufacturers recommend this.

I thought that the main criteria was that the steerer bung was in line with both of the stem clamp bolts.
This will, obviously, not apply so strictly, during the “spacers on top” phase of testing.

I only have one bike with a carbon steerer, so I may be wrong.

There is usually a limit to how many spacers you have below the stem

Go for a long ride at max height. Go for another long ride @ 1 spacer down. Repeat down the steerer until you do a long ride where it feels less comfortable. Go back up one spacer and thats your sweet spot.

One more question after watching a couple of videos whilst adjusting down a couple of spacers…..how to I know if the steerer bung is still positioned against the stem bolts and just how critical is that on a carbon steerer (some videos mention it others don’t).

If the bung isn’t bracing the tube against the tube does that require a different length bung to be bought in order to do test rides in these new positions ahead of cutting the steerer?!

As mentioned above, I’d leave a bit above just in case. You might get a bad back and enjoy a slightly higher bar for a bit

Yeh but it’s in the uncut setup that there’s the risk the bung isn’t bracing against the height of the steerer bolts.

Bump re what to do if the clamp bolts don’t align with the lowered stem bolts?

Buy a longer expanding steerer bung?

I wouldn’t have thought it would be an issue. Some of the stem bungs are pretty flimsy. Certainly the one on my CX bike would not resist the forces involved if you took it to the point where you cracked the steerer. It would simple compress. I think steerers are likely to be fine unless you are really inept.

Buy a cheap torque wrench to be sure?

I got something like this

https://www.wiggle.co.uk/birzman-torque-driver-5nm

I honestly can’t remember if mine was 5 or 6nM – topeak do a similar one. But it was right for the stem, bars and seat clamp which are normally 5 or 6. Flying my roadie at least once a year to go on holiday made it worthwhile.

Yes got a torque wrench and it is that sort of order of magnitude on the steerer bolts.

As an update the shop finally emailed me back stating that the manufacturer state no spacers above the stem and use their bung to maintain the warranty……i.e. no test rides possible ahead of cutting the steerer which seems crazy. Have to go down in smallest steps and hope not to go too far rather than bracketing as described above……or risk invalidating the warranty (if you admitted it which I guess by contacting the shop I have now). Bugger.

Expanding bung should be fitted within the section of the steerer that the stem clamps. These bungs can require a large amount of torque to stop them slipping, and the forces they apply make the steerer tube expand. It’s easy to test – remove the bung and your stem should slide on and off the steerer tube with ease. Now refit the bung and really tighten it up – your stem will now be more difficult to remove due to the expansive forces created by the bung.