Does that 7.2lbs for the rocket include the shock? Size medium?
Big headtube (1.5/taper/44mm)? bolt through rear? nice big seat-tube?
anyone from 18 bikes want to tell us what their frame weighs?
Bike Forum
So -Steel FS bikes...
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Posted 4 months ago #
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brant - Member
How do you define better?Obviously that is variable, but lets go with, offers the same/improved performance for a lower cost, that seems to be many peoples point?
Posted 4 months ago # -
How do you define better?
one (or more) of cheaper/stiffer/stronger/lighter improving without detrimentally affecting the others(I'm assuming you do want stiffer in an FS frame)
Posted 4 months ago # -
its not better its different and that doesn't even matter.
what you need to be asking is does the bike as a whole perform in a way that its material is the last thing on your mind. in this case I'd happily say yes.
carbon is "better" but many people worry when they own it.
Posted 4 months ago # -
I'm assuming you do want stiffer in an FS frame
Depends, there's an argument in motorcycle design that frames got too stiff, which is fine on a track where the surface is perfectly smooth, but if you hit a pothole mid corner on a normal road and there's no flexibility in the frame the suspension (bikes leaned over) can't do anything about it as its not perpendicular to the road.
One of the mags even commented on the cannondale prophet being a bit flexy, but all the better for it.
Posted 4 months ago # -
Thanks Cy for the link, very informative.
As an aside, there is a lot of prototyping work done in steel, the 2005/6 Enduro being one notable case. At that time, the Enduro in it's production form featured a lot of complex welds and semi-monocoque pieces that you simply don't see the like of anymore, probably because the production labour costs must have been very high. Getting the geometry right before the moulds are created is obviously paramount.
The notion that one bike is "better" than another is becomingly increasingly subjective, with personal taste becoming the deciding factor for many which I think is where Brant was going with this. The proof will be in the riding, the only way we'll know for sure is for people to test ride the bike and see how it feels.
Posted 4 months ago # -
I'm assuming you do want stiffer in an FS frame
That depends entirely on where the stiffness is. There's a reason why chain and seatstays aren't made of 2" thick tubing.
Posted 4 months ago # -
I'm assuming you do want stiffer in an FS frame
Ask Mr Vouilloz about his opinions on that one....
Posted 4 months ago # -
There's a reason why chain and seatstays aren't made of 2" thick tubing.
tyre, chainring and heel clearance would be difficult, and it would be heavy.
Posted 4 months ago # -
was is that the original ad/web/page? If so the graphics etc that they used have really aged well haven't they.
Yeah from '97 / '98. Orange are good at marketing and making things look good
Posted 4 months ago # -
Those thinking/questioning about the "stiffness" issue around alu/steel need to read the page that Cy has linked to.
Posted 4 months ago # -
That depends entirely on where the stiffness is. There's a reason why chain and seatstays aren't made of 2" thick tubing.
It's uneccecary as its a smaller triangle than the front, theres 2 sets of them and there's no space?
Those thinking/questioning about the "stiffness" issue around alu/steel need to read the page that Cy has linked to.
The irony of saying we shouldn't question an essay which talks about questioning others logic?
Posted 4 months ago # -
anyone from 18 bikes want to tell us what their frame weighs?
We don't actually know the frame weight of the bike that's been pictured, it was a proof of concept built using tubing we had in stock. Weight was not a concern as it was being built. The bike as pictured is just shy of 32lbs with Deore/sun ditch witch rear wheel, X9 drivetrain, Tapered steerer 140mm thor, Joplin 3, Pro2/dt4.2 front wheel, easton Havoc bars and Magura MT6 brakes. Not too shabby for a frame designed and built in three weeks but the next one will be better.
We are aiming for a very similar weight to the rocket on the next frame with some of the same features - tapered headtube, 140mm rear travel, 160mm fork, 142x12 dropouts, 30.9 seatpost. There are some more details here. We have stepped up the tube sizes to increase stiffness whilst reducing the wall thickness on other tubes to save some weight. This has created some problems with bending the tubes for the rear end, so we have had to design and build a bender from scratch to overcome this, hence the delay. This bender was completed today so the frame should be finished relatively soon.
I'm not going to get into the arguement of steel vs al as I don't think it's that relevant. If you end up with a good frame (performance,weight,looks,price etc), does it really matter what it's made from?
Posted 4 months ago # -
does it really matter what it's made from?
No but key nowadays is strength to a low low weight. Thats how I see things. After all, how many porky 140mm etc travel frames are on sale nowadays?
853 steel is nice and will give a frame (in a crowded market) a USP.
Why is everyone raving about Transition all of a sudden? Yes they are good frames but is it a 'new-found' fashion thing???
Posted 4 months ago # -
I am no engineer so cannot hope to offer anything useful on that score however I can think of one compelling reason why steel FS have not been as popular with designers as Aluminium.......
The majority of riders don't have the first idea about the relationship between materials, their use in any particular context and the ride they experience; that leaves the door open for the marketing department to have a field day... and they decided a long time ago that steel FS was a no-go.
As Cy says on the Cotic site the industry believes... "FS bikes are made of Aluminium right??!"
To me though, my BFe is my favorite bike. I have had the chance to ride bikes from Norco, Santa Cruz, Transition, Intense, Kona, Corsair and more and hands down it is the BFe and first generation Blindside that always put the biggest smiles on my face.
I have never had so much fun on a HT as on a BFe.... it is a keeper and I find myself wanting to go places it excels. So if Cy Turner and his Cotic team of designers, riders and others have come up with a steel FS, I for one sure as hell want to find out if it has the ability to replicate the same reaction in me as the BFe does.
I am sold on my Cotic to the extent that I push the locals here to ride it and see what they are missing. Search out the chance for a Demo people..... it might not be what everyone is looking for but for those of us who ride steel HTs.... FS.... why not if people like Cotic can make one work.
Posted 4 months ago # -
Why is everyone raving about Transition all of a sudden?
Because they are lovely.
Posted 4 months ago # -
No but key nowadays is strength to a low low weight. Thats how I see things. After all, how many porky 140mm etc travel frames are on sale nowadays?
I meant all things being equal, if two frames weigh the same, cost the same, same travel, stiffness, geometry, features etc but one was steel one was aluminium, would it make any difference?
Posted 4 months ago # -
That sounds nice 18 bikes. Thanks for answering.
We are aiming for a very similar weight to the rocket on the next frame with some of the same features - tapered headtube, 140mm rear travel, 160mm fork, 142x12 dropouts, 30.9 seatpost.
Get this in at around 7.2lbs for a medium with RP23 and you're there I reckon.
Posted 4 months ago # -
I think too much emphasis is placed on the weight of frames etc, when the majority of riders aren't exactly racing whippets.
Posted 4 months ago # -
The frame we are building is on the large side, so it's weight should be a good sign of what could be done. What we are ultimately aiming to get is a full suspension platform* that we can build custom front ends for, this will be where we can start to push the weight limits. For example, we will be able to use a different shock to give 120mm travel, use some different tubes in the front end and drop a little more weight out, whilst still being able to build to whatever geometry people want.
I think the next couple of years will be quite interesting in terms of steel bikes, not just full sus
*This may or may not be a single pivot steel swingarm, we are looking into other options too.
Posted 4 months ago # -
True but even a pound in frame difference can make a frame feel different can't it (to any rider).
Posted 4 months ago # -
The irony of saying we shouldn't question an essay which talks about questioning others logic?
Not saying people shouldn't question, just saying that there some ideas regarding stiffness and appropriateness of steel and alu on that page that add to the discussion (they don't end it).
Posted 4 months ago # -
Is there any info on the 18bikes website about the frame Matt?
Posted 4 months ago # -
True but even a pound in frame difference can make a frame feel different can't it (to any rider).
and i think some people can over analyse about the "feel" of a bike.
Posted 4 months ago # -
From Cy's explanation
The key thing here is that steel was right for this application, right for the Rocket, where high loads are going into the frame from the long forks and the type of riding a 150mm travel trail bike encourages. This meant that the high strength of steel made the weight of the frame competitive with other materials with a level of strength and durabilty we were really happy with.
In other applications - shorter travel frames for instance, say 100mm both ends - where loads are lower and the riding conditions aren't expected to be as arduous, these don't suit steel so well because you can't go much lighter than the Rocket in steel whilst maintaining the durability. You end up with a short travel frame which would be very heavy for its class and massively over strength.
The bold bit is exactly what I started off referring to.
Posted 4 months ago # -
I think too much emphasis is placed on the weight of frames etc,
Except when we're comparing different materials in frame manufacture. Only a maniac would buy a frame which id the same price and rides identically to another but is heavier.
Posted 4 months ago # -
Only a maniac would buy a frame which id the same price and rides identically to another but is heavier.
Unless that maniac had other concerns that were not served by the lighter frame (and were served by the heaver one), such as longevity, repairability, or something else not covered by your overly general sweeping statement
Posted 4 months ago # -
Taking Cy's essay from a geeky perspective (I'm sure he's right and I'm wrong as he's more qualified than me).
He quotes the 2nd moment of area in his reasoning why a 35mm seatube is better in steel than aluminium.
But the 2nd moment of area deals with bending a tube/beam/object.
Why not apply the polar moment which deals with the application of torque to the beam? The seatube is essentialy fixed at the top tube and downtube, then twisted at the pivot in CY's design?
[edited]
I think I've thought it through, correct me if I'm wrong.To build a 'perfect' frame (irrespective of weight), you would want to minimise the the 2nd moment of area (which would allow the wheel to twist, which is bad), but still allow some polar moment to let the wheel track the ground on flat (but rough) turns (which is good).
Posted 4 months ago # -
Wors - Not as yet, there are some more news stories if you look back through the archive but not a huge amount. As I said, the tube bending has caused a real delay. The most up to date stuff is in the news story I linked to already and in the Flickr Set
EDIT - Here's one of the other news stories
Posted 4 months ago # -
So are we going to get a lugged FS one day? Would lugs increase stiffness or strength? For someone with no idea how to build a frame, I'm finding it all very interesting.
Posted 4 months ago # -
Proper old skool construction lugged steel FS with modern geo & supension would be WIKKID.
Posted 4 months ago # -
So are we going to get a lugged FS one day? Would lugs increase stiffness or strength? For someone with no idea how to build a frame, I'm finding it all very interesting.
The problem is luggs have to be cast or forged, both carry tooling costs, and unlike road bikes where the geometry & tube diameter hasn't changed in 50 years amd only changes a little between sizes, you'd probbaly need a different set of luggs for every design and size of frame, which would be prohibitibly expensive.
Posted 4 months ago # -
Would the following statements be too contentious?:
-Steel should at least be considered for certain elements within an FS bike frames where there is a balance to be struck between Strength, stiffness and weight, as it is not always the case that aluminium or steel offers the optimal choice in all cases (See Cy's linked article about his own experiences when designing the Rocket)... Basically an open mind is better than an entrenched position...
-In general steel lends itself to fabricating prototypes, short runs and custom frames for both HT's and FS bikes better than aluminium...
-Not all steels are the same, and hence 853 and 953 frames cost plenty more than generic gas pipes welded together with a DMR sticker slapped on...
-Weight is not the only performance criteria for any bike...
Posted 4 months ago # -
There are three things that determine how a bike handles. In DECREASING order of importance:
1) Geometry
2) Tube thickness (stiffness)
3) Material (weight)Since steel has a higher tensile strength than aluminium, you can use thinner tubes of a smaller diameter - hence the frames may be not as stiff for the same (or heavier) weight. Titanium has a higher tensile strength as well, hence thinner tubes and lighter weight, but again tube diameters tend to be fixed (by the aviation industry originally), so stiffness will suffer.
Any decent steel builder working with 853 would laugh at the idea that one couldn't make a good FS frame - after all geometry is already established. It would however be uneconomic compared with the high throughput mass production of aluminium frames, and it's easier just to make hardtails instead.
How stiff a bike with 3" of travel needs to be is a moot point. But I'd love an 853 single pivot frame.
Posted 4 months ago # -
The way I see it Cotic make steel frames, thats their position in the market. So they want to sell a f/s frame, it makes sense for them to develop a steel one. Its different and will apeal to their existing customer base. All the guff about it being the right material for the job is just marketing.
Posted 4 months ago #
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