[Closed] 853 Is it really better?

Peter, then I suggest the butting was different or there was some random variation in the welds (ofc there is always some differnce frame to frame). the YM for both materials is the same so using the same so in principle the ride should have been the same.

Quite possible that the welding detail on the DN6 frame was simply different due to the different material and this created either stiffer or more flexible junctions. It's also possible that 2 DN6 frames would not ride itentically due to variations in the actual weld detailing, within tolerances specified by the frame manufacturer, adding or taking away stiffness from a frame junction.

Or the fact that 2 different metals behave/flex/whatever differently. You're clutching at straws now, you know that don't you? 🙂
Because you've not ridden the two bikes back to back..... I have.

I'm not saying you're wrong about the very slight difference but riding the two with different length travel forks will have made a difference too so it's hard to isolate the two...

Yeah, you'd think the one with the shorter fork would feel a bit more lively, wouldn't you? In a way it did - It steered faster and climbed better, but it felt 'dull' doing it. More solid. Heavier, even though it wasn't.

I'll say again, it's only a slight difference, but it's there, no doubt about it. 🙂

Don't forget I've got both too...

Or the fact that 2 different metals behave/flex/whatever differently

Sorry Pete, that's just wrong. Ask anyone who knows the basics of material science.

Or the fact that 2 different metals behave/flex/whatever differently

I've just had a trawl back through the pics of my bikes at the time, and I've actually been telling a lie!

I had the exact same Rebas on both bikes (I sold the Recons a lot earlier than I thought) and a lot of the same components - I swapped all the bits over to the DN6 and when the 853 frame broke. Forgot about that...!
So the first back to back test was with the same build kit!!
And when I rebuilt the 853 after it was repaired, I put 140mm Vanillas on it, not 130mm Recons, so it had longer forks on than I thought it did. Even more curious then!

So I'm comparing this
[img] [/img]

With this
[img] [/img]

Exact same wheels and tyres & forks. Comparable stem, saddle, bars, seatpost, cranks, headset. Similar brakes - Both Louises. 🙂

teddy - there is plenty of difference in what you call 'weldability' of steel
also while you point to the seatpost diameter, i would like to call 'titanium' for saddle rails

EPIC FAIL

No, it's not at all. I may not know the 'science' behind it like the cleverclogs do, but similarly none of you rode both bikes, back to back, on the same trails, week-in, week-out for the best part of a year, did you? 🙂

I'm not saying it's night and day. I'm not saying it makes any difference that can be measured. But there was a difference that I could feel, end of story. 🙂

In the end I sold the SS because I wasn't riding the 853 as much as I'd like to, and it was my favourite bike. And it still is. I've never had a bike fit me so well, feel so right and ride so well.

PP, the Young's modulus for both steels is the same. It's not a straw, it's physics.

I don't claim that your feeling that the bikes rode differently is some phantom thing that you were imagining, but it's not the material directly. It may be some detailing (like welding detail) that is different. also, try as we might, not all frames are equal in the real world.

More concrete evidence is in your photo, as someone pointed out that there's a head tube gusset on the DN6 version which doesn't appear on the 853 version. this will stiffen the head tube junction. who knows what other detailing differences there are elsewhere? The chain and seat stays were (probably) the same material on both bikes as not many folks make "full" 853 frames (see Cy's comments on the soul)

Plus everyone knows blue paint is stiffer than red paint

but believe whatever you want really.

Dropout design could (possibly) account for some loss of stiffness on the 853?

PeterPoddy - Member

No, it's not at all. I may not know the 'science' behind it like the cleverclogs do, but similarly none of you rode both bikes, back to back, on the same trails, week-in, week-out for the best part of a year, did you?

Of course I haven't.

The point is there is proven science (Young's modulus) stating the metals flex in the same way. You can't contravert this and there are a heap of other factors explaining your experience which you are choosing to ignore.

So it is, indeed,

[img] [/img]

{searches for the double facepalm pic}

if there were any O/D differences between the the 2 tubesets used or a significant difference between butting and wall thickness then the frames are not the same. (853 was possibly .8-.5-.8 and 4130 i guess something like 1-.7-1)

so you are not comparing 2 identically dimensioned frames of different materials.

so you are wrong and the armchair internet scientists are right.

you sure the yound moduli for the two materials are the same are ya?

as i understand it they are two differing alloys. id be suprised if it was.

certainly varies a shed load in differing alloys of aluminium...

Ha classical STW thread this is turning into ie guy who is so called Rocket Scientist versus weekend warrior!

Reynolds suggest ER70-S filler wire to weld 853. They do not say it is the only stuff to use just that it works.

I think blue frames always ride better than red ones...

853 Inbred used 0.8/0.5/0.8. DN6 use 0.9/0.6/0.9. DN6 is therefore between 16% and 19% stiffer depending on the tube OD.

[url= http://reynoldstechnology.biz/assets/pdf/rtl_steel_alloys_extract.pdf ]Reynolds materials stuffs (warning; pdf link)[/url]

basically all their steel alloys (and I believe 525 is chromoly steel and roughly equal to 4130) have the same "stiffness" as they list it (pretty sure the number is Young's Mod expressed in MPa but not 100% certain). Some variance across different alu alloys but <5% variance, not really a shed load 😉 (although admittedly they only cover some alloys and there are many for alu, plus many different tempering standards)

Tensile strengths also shown and that is where the variation is

don't need to be a rocket scientist to know these things, Young's mod is covered in A-level physics (at least it was 20 years ago when I took it)

5% change in stiffness? that sounds noticable!!!

Reynolds 853 stiffness 207 GPa.

I agree with PP. I had a DN6 inbred and swapped the bits over onto an 853 Inbred. I thought there was a different feel to the ride. The 853 feeling a bit more "lively". But that was probably down to the colour difference. Everyone knows Volvo biscuit biege produces a more responsive lively bike than red. No way was that down to riding the two bikes back to back. 🙄

Having said that the Singular Swift I have now rides better than both. Which does make me agree that Frame design, fit and wheels make just a big as difference. Plus its a nice blue colour which is bound to make a difference....

red or any variation on red gives a better ride than blue. pure science fact.

And purple is even better than red or blue - takes the best of both 🙂

tracknicko - Member

you sure the yound moduli for the two materials are the same are ya?

as i understand it they are two differing alloys. id be suprised if it was.

certainly varies a shed load in differing alloys of aluminium...

This is the same FAIL as peter poddy. Youngs modulus is the same for all aluminium alloys, give or take 2% but often that is down to differences in measurement.

Think of it like this:

Two identical shaped diving boards side by side, one made of 853 and one made of 520. Lets simplify the numbers 853 and 520 have the same stiffness (also called youngs modulus, elastic modulus or E), but 853 fails at 100 and 520 fails at 50.

So I put 49 kg on the tip of each diving board, the tip of the 520 board bends down by 20mm, the tip of the 853 board bends down by 20mm, then I add 2 more kg, the 520 board fails it buckles and bends, the 853 board just bends a bit more. I keep upping the weight on the 853 board to 99 kg and it keeps just bending more, but when I get to 101 KG it fails also. This is the difference between stiffness and strength.

ummmm thanks for your magical explanation of yield strength.

here's some number for youngs modulus:

pure aluminium. 96GN/m^2 or GPa if you like.
2024 74
5083 71
7075 72

Mild steel 207
0.4%C steel 210
Stainless 205

small differences indeed. but combined with geometric changes they certainly may well be noticable.

PP, isn't that two different seatposts? Maybe even saddles can't see the top one...

My Kona has a 27mm seatpost, which is out way long (as the frame is a little small and my body has a funny geometry:-)) and this is the most comfy hardtail I've ridden - usually using fairly narrow tyres too as it's primarily a commuter - I reckon this makes a big difference.

tracknicko - Member

small differences indeed. but combined with geometric changes they certainly may well be noticable.

See the below image. Deflection of the free end (thats the right handside)= (w(l^3))/12EI if we make w, l E and I all equal to 1 then the deflection is 1/12E where is youngs mod then:

e = 200 gpa (thats 200 with 9 zeros) deflection = 4.1667 e-13
e = 204 gpa defelction = 4.08496 e-13
e = 207 gpa deflection = 4.025 e-13
So if we fiddled witht he numbers to make them 4.1667 mm, 4.08496mm and 4.025mm I'll bet you cannot tell the difference. Or even 4.167cm 4.084cm and 4.025 cm thats a difference of 1.4mm over 4cm, its small.

[img] [/img]

I'm with the naysayers - two frames with identical design in 4130 and 853 will not feel different. I don't think it's clear whether the DN6 and 853 versions of the frame [i]are[/i] an identical design.

I don't think you can underestimate the effect of psychology in a sighted test either. Just look at all the rubbish that people talk about hi-fi cables (just to open another can of worms).

what? L and W are both 1?
thats a wierd shaped beam but nevermind i take your point...

right eff this. all im saying is.. there IS a change in stiffness. particularly if OD and ID are changed between models and gussets added removed as well...

indeed i was saying there IS a difference in youngs modulus.

so don't 'EPIC FAIL' me like some kind of engineering keyboard hero. Technically you are wrong. whether by much, and whether you can feel it or not is another issue.

@toys19 - To put it another way: there's 3.5% difference between 207 and 200. That means there's a 3.5% difference in stiffness (if you make two identical shapes with the two different materials). Really no need to make it more complicated than it is.

I don't actually think there would be a 3.5% difference in YM between 4130 and 853, but I haven't seen any more than estimates yet. Engineering calculations are not generally accurate to 3.5%, so I'd still consider the two figures to be identical for most working purposes.

[b]djcombes[/b]

I don't think it's clear whether the DN6 and 853 versions of the frame are an identical design.

yeah, it is clear, Cy clarified higher up that the butting is different between 853 and DN6 versions of the Inbred frame (853 has thinner tubes).

[b]cy[/b] <- Mr Cotic, incase you didn't know (as if!) and were wondering about his quals.

853 Inbred used 0.8/0.5/0.8. DN6 use 0.9/0.6/0.9. DN6 is therefore between 16% and 19% stiffer depending on the tube OD.

that plus the gussetting at the head tube of the DN6 version will be enough to change the feel significantly. but the argument seems to have moved on into a physics lesson 😉

No way is purple or red a better ride than blue. I cannot accept that.

As one of the relatively few people to have actually owned and ridden a purple bike, I can categorically state that it's better 😉

djcombes - Member

@toys19 - To put it another way: there's 3.5% difference between 207 and 200. That means there's a 3.5% difference in stiffness (if you make two identical shapes with the two different materials). Really no need to make it more complicated than it is.

Not to mention that if I hadn't simplified the above calc you actually find that the difference in E has very little effect on the deflection, what makes a massive difference is section.

so don't 'EPIC FAIL' me like some kind of engineering keyboard hero. Technically you are wrong. whether by much, and whether you can feel it or not is another issue

You did make an EPIC fail lets face it, technically I am right, you were just spouting stuff without any technical or practical knowledge. There are no differences in youngs modulus between aluminium alloys. If you want to split hairs by your method of accuracy I can guarantee you that no two frames are the same, small diffs in diameter, differences in the welds, maybe more paint on one than another, be careful what you buy imagine if you ended up with one that was too stiff...

clubber - Member
As one of the relatively few people to have actually owned and ridden a purple bike, I can categorically state that it's better

But did you ride it back to back with a blue bike? No....I thought not. 😛

I on the other hand had a Purple kona (eggplant actually if you want to split hairs) at the same time as a Blue kona. Can you guess which was better?

(The blue Kona was also 853 as opposed to the Purple which was 4130; but thats pure subjective cooncidence here 😈 ).

I'll EPIC FAIL whoever I like, particularly those who claim to disprove Young's modulus!*

*I am aware this doesn't really make sense.

cynic-al - Member

I'll EPIC FAIL whoever I like, particularly those who claim to disprove Young's modulus!*

*I am aware this doesn't really make sense.

Don't worry we got the gist..

Missed the comment by cy.

I think that some of the engineers are making the point that a difference in feel between frames is down to a change in the design, enabled by different material properties, rather than some feel of the material itself.

We all agree: there's shouldn't be any need for anyone to argue over this.

[b]djcombes[/b]

We all agree: there's shouldn't be any need for anyone to argue over this

you appear to have forgotten what site you're on. check the URL *slowly* and then rejoin the group... 😀 😉

I think that some of the engineers are making the point that a difference in feel between frames is down to a change in the design, enabled by different material properties, rather than some feel of the material itself.

Bingo

Andy - Member

clubber - Member
As one of the relatively few people to have actually owned and ridden a purple bike, I can categorically state that it's better

But did you ride it back to back with a blue bike? No....I thought not.

I on the other hand had a Purple kona (eggplant actually if you want to split hairs) at the same time as a Blue kona. Can you guess which was better?

I had a purple Tange Prestige frame, which was immensely springy, and eventually broke.

Ridden back to back - at a distance of 13 years - my current white 853 frame is much stiffer, far less springy and definitely not broken.

All components are exactly the same, except where they aren't.

I like white ( At the moment, because it's clean.)
Egplant on the other hand is a pointless food.

Bingo

it doesn't take an engineer or frame designer to work out that tubing dimensions of a frame can change if the material properties allow it.
tubing O/D specs are freely available on the internet along with the butting specs. it's not rocket science just tubes thicker at the ends and thinner in the middle joined together.

pffft, eggplant is not a good purple for riding, far to dark and infected with the dullness of blue.

Imperial purple is the only shade of purple to have.

[img] [/img]

^^^^^^^ That's definitely blue.

Not remotely purple.

Therefore not as good, by definition.

(It also seems to be a midget's bike?)

Second Moment of Inertia