Uncut steerer?

General cycling advice ( NOT technical ! )
PH
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Re: Uncut steerer?

Post by PH »

cycle tramp wrote: 4 Jun 2023, 8:40pm However, as Reynolds are making 400mm long steerers, then the only way you can explain the lack of steerer height adjustment (in the june/July 2023 cycle) on bikes featured on pages 63 and 65 is cost cutting on a mirco level..
Both of those bikes have aluminium forks. where different rules apply. The Trek looks to be similar geometry to my Trek Allent E-bike, which has a high front end without a need for lots of spacers.
The reasons steel forks may be supplied shorter than some riders would like is most likely the explanation Colin gave above, that is they're cut down when the bike is built from the frameset, to what the designer thinks appropriate.
I fully understand the economies of scale, I don't think it applies in this case, firstly because i doubt any steel bike producer is dealing in the volumes where it would apply and secondly the standardization of a component, the steerer, is likely to provide greater economy of production.
cycle tramp
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Re: Uncut steerer?

Post by cycle tramp »

PH wrote: 4 Jun 2023, 10:03pm
Both of those bikes have aluminium forks. where different rules apply. The Trek looks to be similar geometry to my Trek Allent E-bike, which has a high front end without a need for lots of spacers.
The reasons steel forks may be supplied shorter than some riders would like is most likely the explanation Colin gave above, that is they're cut down when the bike is built from the frameset, to what the designer thinks appropriate.
I fully understand the economies of scale, I don't think it applies in this case, firstly because i doubt any steel bike producer is dealing in the volumes where it would apply and secondly the standardization of a component, the steerer, is likely to provide greater economy of production.
...I thought the only exception were carbon forks with a carbon steerer... if there's a similar rules for alloy, which website was the warning posted on?
... if standardisation of the length of steerer provided the economy then why not leave them all uncut at 400mm and let the rider decide when they've purchased the bike (just like the old mountain bike bars from the 1980's) After all, the designer may not actually ride the bikes they design, and different people have different body shape.

..as it is the upshot of the aheadset steerer can make it difficult or expensive to change your riding position should you find that the steerer has been cut too low
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PH
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Re: Uncut steerer?

Post by PH »

cycle tramp wrote: 4 Jun 2023, 10:46pm ...I thought the only exception were carbon forks with a carbon steerer... if there's a similar rules for alloy, which website was the warning posted on?
I'm getting a bit bored by this, what's wrong with looking for yourself?
Here's the first Google hit, took 20 sec:
Check the amount of spacers required for the fit. No more than 40mm of spacers to be used (above and below the stem combined) for
aluminium steerer tubes, and 30mm for carbon steerer tubes. We recommend at least 5mm of spacer above the stem, so the preload
cap is loading against a spacer not the stem itself
http://www.kinesisbikes.co.uk/files/tec ... NS-WEB.pdf
... if standardisation of the length of steerer provided the economy then why not leave them all uncut at 400mm and let the rider decide when they've purchased the bike
Already answered by others upthread, what's done to sell a bike isn't the same as the manufacturing process.
jb
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Re: Uncut steerer?

Post by jb »

The amount of seized up quills one came across shows how little this 'facility' was ever used. The A head set must rate amongst the top improvements to cycling ever - next to better tyres.
Cheers
J Bro
maximus meridius
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Re: Uncut steerer?

Post by maximus meridius »

PH wrote: 4 Jun 2023, 11:48pm
cycle tramp wrote: 4 Jun 2023, 10:46pm ...I thought the only exception were carbon forks with a carbon steerer... if there's a similar rules for alloy, which website was the warning posted on?
I'm getting a bit bored by this, what's wrong with looking for yourself?
Here's the first Google hit, took 20 sec:
Check the amount of spacers required for the fit. No more than 40mm of spacers to be used (above and below the stem combined) for
aluminium steerer tubes, and 30mm for carbon steerer tubes. We recommend at least 5mm of spacer above the stem, so the preload
cap is loading against a spacer not the stem itself
http://www.kinesisbikes.co.uk/files/tec ... NS-WEB.pdf
Interesting. I wonder what the problem is with spacers above the stem? I am not an engineer, but I can see how a long length of steerer tube below the stem, subject to force by the rider putting weight on the bars, might eventually fatigue. But any "spare" length above the stem is just waggling about, surely?

I'm not particularly worried, as my steerer is steel. But there is 80mm of spacers under the stem. A quick google for "how many spacers under the stem on a steel steerer" gives the top result on a the web site, well, here!

Anyway, it seems that yet again, steel is a better choice. Fatigue limit, and all that.

Though interesting point that was made in my googling. That a long steerer tube above the headset will be placing more strain on the headset, moments of turning and all that. Whether that has any actual effect, I wouldn't know.
Stevek76
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Re: Uncut steerer?

Post by Stevek76 »

LittleGreyCat wrote: 2 Jun 2023, 11:12am Do bikes come from the manufacturer with uncut steerers and are then cut down at the shop?
Or are Spa particularly thoughtful in this?
Depends on the operation of the shop/chain and what they ask for. I know for certain that Halfords Boardman bikes for example come to shop cut and fork already inserted from the factory in the far east. The only things halfords do is stick the wheels and pedals on, saddle in and align the handle bars around (essentially the bike is in the minimally disassembled state you'd use if transporting it in a bike box/bag on a plane)

Smaller outfits often do more of the assembly themselves though not all will leave the steerer totally uncut unless asked in advance. If they sell their own brand bikes as frame only that's usually an indication that they'll have the forks with full length steerers. My transport/pub hack is built up by myself from a cheap planet x steel frame which came as full length steerer and is used as such.

I think this is generally only an issue for those of us with particularly long leg/short torso ratios though as we're probably the trickiest body shape to fit a non-custom frame to.

As others have mentioned, non-steel steerers have limitations in this regard so even shops that are flexible here may insist on some level of shortening on any assembled bike for safety/liability reasons.
That a long steerer tube above the headset will be placing more strain on the headset, moments of turning and all that. Whether that has any actual effect, I wouldn't know.
eh, worst case you might have to switch out the bearings on a slightly more frequent basis though whether that's enough change to leave the realms of 'longer than the life of the rest of the bike' I doubt.
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maximus meridius
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Re: Uncut steerer?

Post by maximus meridius »

Stevek76 wrote: 5 Jun 2023, 12:29pm
Maximus Meridius said
That a long steerer tube above the headset will be placing more strain on the headset, moments of turning and all that. Whether that has any actual effect, I wouldn't know.
eh, worst case you might have to switch out the bearings on a slightly more frequent basis though whether that's enough change to leave the realms of 'longer than the life of the rest of the bike' I doubt.
Yes. That's what I thought. And probably only then a very vigorous rider with a far longer than usual length of steerer under the stem.
cycle tramp
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Re: Uncut steerer?

Post by cycle tramp »

PH wrote: 4 Jun 2023, 11:48pm I'm getting a bit bored by this, what's wrong with looking for yourself?
Here's the first Google hit, took 20 sec:
Check the amount of spacers required for the fit. No more than 40mm of spacers to be used (above and below the stem combined) for
aluminium steerer tubes, and 30mm for carbon steerer tubes. We recommend at least 5mm of spacer above the stem, so the preload
cap is loading against a spacer not the stem itself
http://www.kinesisbikes.co.uk/files/tec ... NS-WEB.pdf
At which point I'll concede my argument, and agree that shorter fork steerers are not an economic argument, but are due to materials like alloy/carbon fibre being used, which when you consider that both materials are likely to fail without giving any warning is far more sinster than any economic plot to save money...
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LittleGreyCat
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Re: Uncut steerer?

Post by LittleGreyCat »

Thanks for the fascinating discussion.
Just been out and measured from the top of the forks to the top of the stem and it is about 355 mm.
For me that is slamming the stem(!) so it turns out that I would probably have been happy with a full 400 mm stem.
Not that I knew anything about uncut (or less cut) steerers before purchase as this was my first new bike since 1995.
Oh, apart from a Giant Dutch bike - which had a whole different geometry.
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531colin
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Re: Uncut steerer?

Post by 531colin »

LittleGreyCat wrote: 5 Jun 2023, 8:44pm Thanks for the fascinating discussion.
Just been out and measured from the top of the forks to the top of the stem and it is about 355 mm.
...............
Picture, please........fork crown to stem is 355mm;
assuming a 700c wheel, you have about the same distance from fork crown to stem as you have from fork crown to wheel axle?
And your bars are 1.1 M above ground level?
pete75
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Re: Uncut steerer?

Post by pete75 »

cycle tramp wrote: 4 Jun 2023, 9:07am
LittleGreyCat wrote: 2 Jun 2023, 11:12am Prompted by all the bike fit questions.

My Spa Wayfarer (brand new) came with an uncut steerer.
I was told that I could move the spacers around to get the best fit, then cut it down.
It is still uncut because the highest possible position seems to suit me.

Looking at most bikes in shops they don't seem to have the same height adjustment.

Do bikes come from the manufacturer with uncut steerers and are then cut down at the shop?
Or are Spa particularly thoughtful in this?
Yes, Spa (and Thorn) are thoughtful in this, for other manufacturers it's just profit.

The steerer is supplied to the factory as long round pipes... its then cut up to make steerer tubes. From the point of the factory, they can get more steerer tubes out of one pipe if they were cut shorter... and as a result need to buy less pipe to the make of 10,000 bicycles, slightly increasing their profit at the risk of useful product life to the customer... as far as the bike manufacturer is concerned that's a win-win situation.

Hence really stupid stubby steerer tubes which can cause neck, wrist, shoulder and back issues...
Not always so. Surly, for example, come with a long, uncut steerer. It's easy enough to put on extender on an a steerer tube which may need raising as the rider ages, and they're not expensive.
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531colin
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Re: Uncut steerer?

Post by 531colin »

pete75 wrote: 6 Jun 2023, 10:26am ...........
Not always so. Surly, for example, come with a long, uncut steerer. It's easy enough to put on extender on an a steerer tube which may need raising as the rider ages, and they're not expensive.
Is that Surly complete bikes, or Surly framesets?
My Genesis frameset came with uncut steerer.....longer than 400mm, i think
pete75
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Re: Uncut steerer?

Post by pete75 »

531colin wrote: 6 Jun 2023, 4:28pm
pete75 wrote: 6 Jun 2023, 10:26am ...........
Not always so. Surly, for example, come with a long, uncut steerer. It's easy enough to put on extender on an a steerer tube which may need raising as the rider ages, and they're not expensive.
Is that Surly complete bikes, or Surly framesets?
My Genesis frameset came with uncut steerer.....longer than 400mm, i think
My experience of Surly is with buying a frame set, and later a set of forks to convert to front disc. Both uncut. Frameset in 2015. Couldn't make my mind up between LHT and one of yours, but when I saw Triton cycles were doing blue LHT for £249.99, that made the decision for me. Don't regret it but doubt I'd have regretted getting a Spa either.
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JohnR
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Re: Uncut steerer?

Post by JohnR »

peterb wrote: 4 Jun 2023, 3:00pm The general rule for carbon steerers is that there should be no more than 30 - 40mm of spacers below the stem, and preferably no more than 5 mm above https://velo.outsideonline.com/gear/tec ... ck-height/
That advice include a recommendation to add an insert if a gorilla "I don’t want to mess around when building bikes for 6-foot-10, 350-pound riders" is riding the bike. It's less clear what's needed for someone less than half that weight.

Anyway, I've got only 25mm of spacers below the stem on my carbon steerer (bike on left with stem turned upwards) whereas there are 45mm of spacers below the stem (turned downwards) on the bike on right with an alloy steerer (both bikes are Spa Elan). Given the time needed to saw through an alloy steerer I feel it's a lot stronger than a carbon steerer.
Two stem positions.jpg
Usually riding a Rohloff-equipped Spa Cycles Elan Ti
LittleGreyCat
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Re: Uncut steerer?

Post by LittleGreyCat »

531colin wrote: 6 Jun 2023, 7:56am
LittleGreyCat wrote: 5 Jun 2023, 8:44pm Thanks for the fascinating discussion.
Just been out and measured from the top of the forks to the top of the stem and it is about 355 mm.
...............
Picture, please........fork crown to stem is 355mm;
assuming a 700c wheel, you have about the same distance from fork crown to stem as you have from fork crown to wheel axle?
And your bars are 1.1 M above ground level?
Fork crown to wheel axle roughly 410 mm

Tops of the flats on the bars roughly 1.1 M above ground.
Wayfarer Front Forks.jpg
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