For my A2 Design Technology project, I aimed to make a device which allowed the rider to adjust their saddle height “on-the-fly”.

After doing a fair bit of research into existing products, it seemed the vast majority of them were either very expensive (>£120), had a small height adjustment range (<3″), didnt work very well, or some combination of all three.

I basically aimed to design and manufacture a device which had a large adjustment range (at least 5″), worked well, but is a simple design, so it is cheaper to make/sell, and easier to maintain. Obviously, due to the target of a much cheaper selling price than most exisiting products, the quality will not be as high, but it should still function as required.

Anyway, heres the finished device.
Please bear in mind-
* Obviously its only a prototype, so obviously it looks a bit industrial/rough around the edges.
* I realise the cable position on the lever mount is not in the best position.
* It had 5.3″ height adjustment, with 6 height levels.

Would appreciate any thoughts you may have- obviously you havent actually tested it, but just reactions to what Ive written/the pics?

Thanks, Duane 🙂

Looks promising, wouldn’t want to hit my knee on the release lever though 😕

Hows it work – gravity dropper copy at a guess?

Looks promising, wouldn’t want to hit my knee on the release lever though

To be honest, its not as bad as it looks, doesnt get in the way any more than a shifter unit.

Hows it work – gravity dropper copy at a guess?

Basically, big spring in a tube, and the inner post is locked at the chosen height with a pin-in-a-hole (think crutches inside out).

As I say, simple (and therefore cheap to manufacture/sell), but it actually works pretty well 🙂

Robust? will the slidy parts wear? Replaceable bushes? snappage?

Looks cool to me but can it really be made cheap enough?

Looks great actually, been wanting to get one of those for a while.

How long did it take to make?

How much did the materials cost?

Have you tested it on a proper ride yet? How was it?

Most importantly of all it needs to work on the narrower gauge seatubes to capitalise marketplace – will it?

hard to respond without seeing it but my first concern with your design would be whether it’s strong enough to stand a rider landing heavily on the saddle without bending the pin or some other part – that’s where all the other hydraulic designs have an advantage.

Excellent work though and good to see some different thinking.

Clubber – how is it different thinking? It is identical in operation to the Gravity dropper

Nice machining on the remote actuator

A useful link

rralph – i thought that the gravity dropper was hydraulic. Sounds like it isn’t then.

The GD is sprung

Hmm not wanting to be too negative but if its a copy of the GD it seems pointless, I suspect they’d make the GD cheaper if they could OR they’re making a big markup.
Couple of things…

Can it twist by accident, meaning the pin-in-hole goes out of line?
Not sure I like the exit of the cable from the seat area BUT thats just an aesthetics thing and mechanically thats better than downwards which introduces curves in the cable so I’d be willing to ignore that if buying.
Holes through tubes are obviously stress inducers, presumably you’ve thought of this and increased the wall thickness as necessary – how much does it weigh?

More Positives –
I like the length of adjustment.
I like cheap, so long as its functional.
One would assume you’ve sized the pin correctly taking into account fat-man-landing and fatigue.

Nice machining on the remote actuator

The lever mount was made entirely using a bandsaw, drill press, file, and emory cloth.

Well done – that looks like a good bit of work there. How long did it take you?

The tricky bit about projects like this (I’m a head of DT) is the starting point, the principle objective of the project and a way to assess if you have achieved them. You have acknowledged that your product is not unique – similar products already exist but your problem with them is that their price point is too high, or to reduce costs the tolerances or mechanisms have been simplified so the functionalty has been reduced (i.e. the range of motion has been reduced so that play is not a problem). Your USP is to provide “top end” functionality at bottom end prices.

To truely evaluate your product you really need to have genuine manufacturing costs based upon projected sales for the unit that that is essentially impossible for a student to do – you just don’t have access to the right figures. Most of the manufacturers creating products such as this operate within a batch manufacturing model rather than mass or flow production.The difficulty you have is that the price difference between high-end and low-end products of this type is quite small so the small details such as the machining of the lever will make a big difference to the final figure and as you have only got to a first operational prototype stage, it is difficult to specify those exact costings and where your design falls into the range.

What board are you sitting?

Oh yes, and if you want it to be production worthy you need to make it economic to sell:

RRP £100
Shop trade £60
Distributor £30
Manufacturing cost £15

So the challenge is to make your seatpost including all materials, packaging and labour for £15 if you want to sell it for £100.

Nip

hey Duane

liking your work. Bit of a hijack, i’m uber interested in a Blade.
couple of Q’s if you would
What size do you have and how tall are you (is it pretty short top tube)
I can see you got it built burly but what does it weigh?
give us a quick run down of it’s pro’s and cons please

Many thanks

Look at the history of (modern) mountain biking and this sort of thing is what made mountain biking. A bloke with a good idea goes out and builds it. respect.

What was the old saying… designed in a pub, built in a shed

Thanks for all the replies.
convert, its WJEC.

AJ- its a small/medium, Im just under 6ft tall- yes its pretty small for me, but its chuckable, and I dont do “epics”.

Yeah, quite a strong build, weight is around 35lbs I believe.

Pros- Its awesome
Cons- Steep headangle- Col will hopefully be selling new linkage plates to slacken the HA.

It can take a beating fo’sho. Heres me riding it on Saturday;

Oh, and I guess I didnt really mean make it to a lower quality, but the tolerances etc needed for a hyrdualic system would need to be higher than that for a spring in a tube surely?

cheers D think i’m gonna press the button in chrome, any one want a 4x?

bassspine – Member

Look at the history of (modern) mountain biking and this sort of thing is what made mountain biking. A bloke with a good idea goes out and builds it.

Correction – a bloke with a good idea patents it. Someone else comes along later and tries to make it cheaper. They get their ass sued.

We use WJEC too – so I hope to see it in the exhibition in Cardiff in November! So what brief were you answering then, or did your teacher submit a specific brief for you?

druidh- calm yourself, Im an 18yr old tech student- not someone about to try and sell this product.

Convert, more likely to be the one up in Llandudno 😉

Brief was the outdoors one.
Do I really need to mention all the stuff about pricing? One of my spec points mentions how much it should cost to make (materials wise)- I was just going to say whether I met that target or not (and if not why not etc etc)… Teacher has mentioned going any more indepth than that…/

Duane. Excuse me, but I never did further education, so mibbe I’m missing something, but surely you’ve missed your brief. If the aim was “to design and manufacture”, at what point does copying someone else still qualify as “design”?

I didnt copy it.
I did not know that it was similar to how the GD works. (Yeah, maybe that means I didnt do enough research, oh well).
Just because something is designed (I have 17 A2 pages to show for designing) the same as something else does not mean it was copied, surely?

Duane – might see it at the Llandudno one, as I tend to go most years (another WJEC teaching tech teacher here). Nice chainge from the furniture related task submitted by quite a lot of A2 students.

Looks a decent bit of construction, and you should be able to hit the “inovation” requirement for a decent grade from WJEC if you have actually improved upon the gravity dropper.

I thinks its a bit harsh to say he has “copied” another design. He has has used similar concepts to solve the same problem. Most innovation is incremental and it is very rare to have totally unique solutions. That’s why the likes of James Dyson are standouts in world industy. Duane is “only” working at A level so that’s not bad stuff. As I said earlier though, because there is not significant innovation and your “problem” as such is that what is already out there is too expensive, the costings are quite important imho. However, I probably know a bit more about the cycling scene than your average DT moderator, so I think you are safe!

Any chance at this stage you could run your design past a local small engineering company to get an “expert” opinion on costings? My students have had to hand in their work to give us a week or so to mark it but maybe your teachers are more generous!

Haha, its due in tomorrow morning 😉

Well, it was due in the week before we broke up for easter, but no-one had finished it yet…

paule, what school do you teach at?

I teach at Wales High – which is in Rotherham, rather than Wales…. I go to Llandudno exhibition as it’s closer than the S Wales one. Also means I can go for a ride on the way home!