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can some of you please measure the thickness of your top tube on your bike/bikes. I am making a bike stand for my GCSE Resistant Materials project and I am trying to draw a CAD design up with a clamp that will clamp pretty much any bike.
All types of frames, need a few so I get a decent idea of how big the clamp needs to be.
steel, aluminium, carbon, Ti. any frames.
Anywhere from approx 30mm to 100mm would cover pretty much everything
30mm to 100mm
I thought that, right, time to design.
100mm! what sort of bike has a TT that big?
Hydroformed frames.
GT avalanches have rather large top tubes, and so do Treks.
I didn't say they did ? He asked how big the clamp needs to be. To clamp some of the curved shaped tubes you need a bigger clamp, look at a Santa Cruz Blur for example
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Better clamping the seatpost IMHO.
Better clamping the seatpost IMHO.
thats also miles away from the balance point of the bike. so it makes the stand a lot less stable.
What about something that supports under the bb and downtube?
That would get round the issues of tt diameter and odd formed frames etc.
What about something that supports under the bb and downtube?That would get round the issues of tt diameter and odd formed frames etc.
the frame wouldn't be held flat and the frame would move so the tt diameter would still come into play to clamp it.
thats also miles away from the balance point of the bike. so it makes the stand a lot less stable.
Have you actually seen folk working on bikes on stands?
Have you actually seen folk working on bikes on stands?
yes, they clamp to the seat post, I know they do, but that isn't the balance point of the bike. where as somewhere along the top tube is the balance point.
[i]thats also miles away from the balance point of the bike. so it makes the stand a lot less stable. [/i]
You are correct, and the likes of Park know nothing.
tbh the balance point is pretty much different on every bike I've ever had in my stand - and of course, changing something like the forks moves the balance paint again. One problem with clamping a top tube (or any frame tube really) is that they are thin and you can deform them - which is why seatposts are clamped.
Hoses and cables on the underside of my top tube, and the front gear cable runs down my seattube...
I'd rather risk clamp on a seatpost than a top tube .5mm thick. plus if cables run along top tube it can interfere with them to clamp around them.
As other people have pointed out, could be tricky adjusting gears in the stand if the gear cables are clamped tight against the top tube, or routing new cables, or removing hoses, or any number of other things.
true, I'm not changing the design as I didn't ask for idea's I just asked for measurements.
I've never had a problem clamping to the top tube, yes you cant put new cables on and stuff like that when it clamps there but I'm not bothered.
Good luck with it anyway 😕
changed the design even though I cant see it working as well.
all hail the leeds freeriders 😉
http://www.leedsfreeride.x10.mx/riders.html
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Sometimes clamping the seatpost can be a bit tricky.
it would be worth having a design that can be easily clamped in more than one place
like you say the CoG of some bikes (hardtails) would be towards the front when they're fully built up. but it would shift a lot as you remove/add the forks, front wheel, rear wheel...
I wouldn't go clamping by the top tube if I was you... you might end up with a lovely dent like this one (courtesy of my LBS a few years ago, a professional did this!)
[url= http://farm4.static.flickr.com/3308/3420926814_ca96494925.jp g" target="_blank">
[url= http://www.flickr.com/photos/32746168@N08/3420926814/ ]DSCF2085[/url] by [url= http://www.flickr.com/people/32746168@N08/ ]ten_sim[/url], on Flickr
As somebody who works regularly on bikes in stands, I'd like to suggest that you focus on a clamp/stand designed around using the seat post. You'll need to also design in a mechanism which enables the clamp to be held firmly enough to hold both wheels off the ground, but clamping anywhere on the frame just raises so many issues. From odd shaped hydroformed tubes to the inevitable damage from pivoting large amounts of force onto a very small area of aluminium/carbon tube - if the brief is to design a stand that will easily clamp virtually any bike, the question really is: why would you want to clamp anywhere other than the seat post?
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that's not bad, certainly simple to manufacture.
I'd round off the corners where the seatpost would go in to avoid scratching and split a bit of plastic petrol pipe lengthwise to cover the edges that are exposed.
You might want a bigger handle on the screw so you can get enough leverage to tighten it sufficiently to hold the weight of a bike - have a looka t the handles on wood and metwork vices where they have a 'pin' through a hole as a good way of achieving this.
Good luck with the project - be interesting to see the finished article.
true, I'm not changing the design as I didn't ask for idea's I just asked for measurements.
I've never had a problem clamping to the top tube, yes you cant put new cables on and stuff like that when it clamps there but I'm not bothered
Really thinking like a product designer there! 😉
Saw your drawing above, I'd say looks harder to manufacture that it could be - the top U section could be a standard tube rather than something you're going to have to get folded for you. The whole top section could just be 1 tube curved, or 2 tubes joined, with your bracket on the end. Easier to manufacture.
Sharp corners look nasty and qr might be beter for height adjustment.
My top tube would get in the way of a top tube clamp!
Ah the pleasures of having 2 top tubes!
yes it will be curved and its all not exact, it will be a quick release to adjust the height I just couldn't be bothered designing a qr. and it will a U section, im not having one bent for me.
My cx bike has a triangular section carbon fibre top tube. How would you clamp that without damaging an expensive frame?
Seat post clamp only I'm afraid - you might find listening to people who know what they're talking about is quite helpful.
i am doing a very similar project for a level. rather than having a curved clamp that can bend, it is easier to make an angled one
then instead of 1 contact point with the frame u get 2 which makes it more secure. then if you have the other part of the clamp you get four points of contact with the frame and it is much easier to accomodate for the curves.
Just wondering how you adjust the angle the clamp sits at so you can adjust the attitude of the bike?
Just wondering how you adjust the angle the clamp sits at so you can adjust the attitude of the bike?
you cant, i havent incorperated that into the design because its a GCSE project not A-level, i just dont have the time to incorparate everything into the design.
nor do i at a-level. it will work well for my bike and i won't gain any marks in doing that. i can put that in the evaluation. that will get me marks. i will also be stretched for time in what i have designed
nor do i at a-level. it will work well for my bike and i won't gain any marks in doing that. i can put that in the evaluation. that will get me marks. i will also be stretched for time in what i have designed
true, evaluations always need something that you can write about that could be improved.