Cycling UK Forum

I am swapping round the bars on my recumbent bike and need to extend the steerer tube to make it all work. Forks are alloy with (presumably) an alloy steerer, ahead-style 1 1/8” headset

I have an external clamp type (Satori) on my Thorn, looks lumpy but does the job. Is there anything else that would sway choice between this kind and the internal quill type fitting (BBB for example)?

arguably the internal type puts lower bending stresses into the steerer, I think, but is itself (in the same material/wall thickness) slightly less strong.

cheers

There's this type of extender
https://www.spacycles.co.uk/m2b0s88p298 ... be-Adapter

It's more streamlined than the external bolted on type however I'm not 100% sure it's suitable for your setup so please investigate further.

I've used the BBB extender for a couple of years without any problem, one extra advantage is you can change the bar height easy like the old days quill stems...

another BBB user here - no problems

The BBB BHP-20 or BHP-21 looks like a really nice solution! Much better looking than external clamp on extenders.

Thanks for the comments. The BBB extender it will be for a variety of reasons: it looks “cleaner”, there may be some adjustment necessary before I get the right height, and given that on a recumbent the steerer comes up between your legs you want as few obstructions as possible! The handlebars on a recumbent are very lightly laden compared to a DF so strength issues should not be a concern.

Steel and alloy steerers are the same external diameter......it follows that alloy steerers have a smaller internal diameter than steel steerers do......there may be internal fitting steerer extenders for alloy steerers, but I never found one.

often an aluminium alloy 1-1/8" steerer will have a wall thickness of 1/8", which means that the bore is 7/8". If so, a quill to a-head converter meant for 1" steel steerers will fit, albeit you will need a mess of spacers and at least one shim to make it all work, with a stem for an 1-1/8" steerer.

cheers

Well, I happen to have one of each... the Satori is on the Thorn and before I decided to change the bars on the recumbent I bought a BBB to make it all look neater, so I can transfer the Satori over, even though the colours won’t look quite right

".....there may be internal fitting steerer extenders for alloy steerers, but I never found one."

plus 1. I have found a few that don't!

Well, the BBB-BHP21 fitted smoothly and snugly into my Thorn's steerer tube, I adjusted the bars to the right height, it all looked good... until I tested the strength by nudging the bars... moved easily. I tightened up the clamp as far as I dared, it just didn’t hold. I degreased the inside of the steerer (well, it was clean anyway) with no more succcess. Satori has gone back on again. Disappointing, but I can’t work out why it doesn’t work.

quill stems are (cleverly IMHO) designed to allow the handlebars to twist if you subject them to a large enough load. This means you are less likely to bend something in a crash, and is an advantage of quill over Ahead. I daresay your extender is able to move in the way intended.

BTW if you manage to exert that amount of force on the thing whilst riding the bike, it is very likely that you are just about to crash, or perhaps you just have done.

cheers

No, I’m very familiar with quill stems, the twisting force required to move my bars was much less than they would have required. I must have done something wrong, but quite what mystifies me.

hercule wrote:No, I’m very familiar with quill stems, the twisting force required to move my bars was much less than they would have required. I must have done something wrong, but quite what mystifies me.

apologies are in order then. I wonder if the wedge was assembled correctly, or if something was bottoming out when it shouldn't have?

cheers