Reducing a bike's weigh by removing material?
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140mm rear requires an adapter. The Cannondale Flash and the new Scalpel runs a post mount rear, so you have to use a 160, but no adapters.0
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ah. Fair enough. Still That avid system, and a split adapter looks like a problem waiting for an opporunity to pounce.0
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The split essentially turns it into a four bar system - the caliper can move if the pivots, the bolts, are not tight enough.
Non split and it is restrained.0 -
As for saving weight:shave a mm off your disk rotors,run 3 bolts on your disks,loose the bottle cage,take a few spokes out your wheels,use presta instead of shrader,sandpaper your rims down to the metal,
If I were you I would invest in some nice wheels,tyres and forkI assume this is French petrol - be careful in reverse - the car will retreat rapidly at the least provocation.0 -
Well Steve Peat did most of those things for the World Champs last year, and more, so there's some merit! Or does he just need some nice wheels forks, tyres and forks :-)0
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Nylon bolts are a good weight saving for blanking any frame holes unused, aluminium bolts where they need to take some weight. Nylon bolts should only cost about 6.5p each.
Weigh your tubes, many 26" tubes are about 160g, Schwalbe 1" tubes about 120g, a mate has always run them in his Zaskar without trouble (inside Conti speed king's - 2.1")
Wheels, I was running an Alexrim on a Shimano M475 hub taken from a spesh, lucked into a Sunringle Equaliser 21 rim also on a Shimano M475 hub, that was a weight saving of over 300g
Likewise with tyres, the better tyres are circa 600g, heavier ones can be around 1Kg, tubeless weighs more than tubed once you add the extra wieght of the required p[arts for conversion.
The weight weenies website is useful (if not very upto date!), and I weigh all components I fit to my bikes so I know what weight I need to beat if I want to reduce it, stems and bars can vary massively.
Avid discs are the lightest of the mainstream brands, often a saving of circa 20G or more, in fact often the next size up in an avid is lighter than the size below in others!
SimonCurrently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0 -
Likewise with tyres, the better tyres are circa 600g, heavier ones can be around 1Kg, tubeless weighs more than tubed once you add the extra wieght of the required p[arts for conversion.
Let's not get into the tubeless weight saving thing again! If you have Roval/Stan's rim the only weight you add is a valve and some sealant, so that does save some weight, also makes using lightweight tyres more sensible IMO.
600g is still a heavy tyre though. Rocket Rons are 410g (claimed, mine are both slightly lighter), and Furious Freds are 295g.0 -
The 600g I was quoting were for a less specialised tyre, yes they are lighter, but I was basing my weight on a more general usage like a Nobby Nic which averages out at around the 550g mark.
You need to be careful with quotes though the FF can weigh from 295 to 465!
http://www.schwalbe.co.uk/c2-1037-schwa ... -fred.html
Yes specialist tubless rims do give a weight saving, but that is then a wheel change.....
SimonCurrently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0 -
but that is then a wheel change
That rather depends on what wheels you have in the first place...
A 2.25" Evo Nic weighs 540g, a 2.1" weighs 470g. Rons are a perfectly good all round tyre though, plenty of grip, you just sacrifice longevity.Avid discs are the lightest of the mainstream brands, often a saving of circa 20G or more, in fact often the next size up in an avid is lighter than the size below in others!
If you want light rotors then Alligator are a better bet than Avid too, significantly lighter, and much cheaper too.0 -
IMO breaking the caliper mount in to two parts by removing the middle brace will completely change the structural function:
- The brake itself becomes active in the structure in resiting rotation, assisted by the trialign washers. i.e. it becomes load bearing.
- The mounting bolts in the frame or fork, are subject to rotational forces
Under breaking I could see the whole unit pivoting around the mounting bolts and completely change the alignment of the caliper to the rotor. In addition the affect on the mounting bolts is different..
I'm not a structural engineer, but I think the formula for torsional strength changes on bolts when braced, because "a load shared is a load more than halved" or some similar aid memoir.0 -
:oops:
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Be carefull removing material. Make sure you round off all edges, not becuase you might cut yourself but because sharp edges & corners increase stress in componants.
Modern parts are designed using 3d modeling software & using finite element analysis to check stresses & remove any excess material. I use 3d cad with FEA and it's surprising where the stresses can run in a componant, anything that looks like a gusset or rib will be there for structural reasons.
When I used to ride on motorbike track days I used to meat a lot of riders who had spent thousands on loosing a couple hundred grams off their exhaust system when they had 3 or 4 stone of excess on themselves.Transition Patrol - viewtopic.php?f=10017&t=130702350 -
IME many very light bikes are ridden by rather overweight riders, too much time spent staring at spreadsheets and not enough time riding!
Still, if people have the money, why not!0 -
I saw some of those chaps on the south downs way last week, some of them I'm sure had heart attacks shortly after - the irony is that it was a BHF organised ride.
Lose the pint not the parts would be my thoughts.
you get the same on motorbikes - chaps spending a grand to get 5 hp more and 3kg less. Lose half a stone and spend the rest on some advanced training.0 -
The new Epics for next year have a 140mm post rear, with a cut down adapter, so I guess SRAM are relatively it's ok, I know it's post-post, rather than IS-post, but still. Think I will try it when I can get bothered!
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post post is very different when cut down, to post-IS though.0
