can a tyre weigh more or less than itself????

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  • can a tyre weigh more or less than itself????
  • xcretro
    Member

    a bit of an odd question I know, well today I bought 2 bonty xr mud tyres for a new build im doing tomorrow and thought I would start weighing stuff that im using on the build so popped one on the scales and it came in at 510g fairly respectable, then i popped the other identical tyre on the scales and it weighed 521g. i thought ahhh perhaps the scales didnt weigh correctly the first tyre so popped it back on – yes, 510g, second tyre back on 521g. Thats an 11g difference between two supposedly identical tyres.

    surely the manufacturing process or quality control is not that slapdash that this is a regular occurance amongst tyres??

    any experiences yourselves with this?

    Premier Icon Northwind
    Subscriber

    That’s not a big difference tbh, I’ve got a pair of Conti Barons that have about 70g difference. Even tubes vary.

    jim25
    Member

    I wouldn’t be too concerned by 11grams!
    Pick all the “new tyre” spikey bits of and it’ll be abit nearer!

    xcretro
    Member

    really? thats insane! surely manufacturing processes are not that vague? what about bike frames? wheels? the 11g difference is about 2.3% difference in weight. am I just ranting for the sake of it? lol is that what happens when you are nearly 40? arrgrghhh

    Premier Icon jam bo
    Subscriber

    2% tolerance. I think your being a big picky.

    dan86
    Member

    Put the heavier one on the back and pull a skid or 2. Sorted 😀

    xcretro
    Member

    Put the heavier one on the back and pull a skid or 2. Sorted

    good thinking dan, do you think its actually done on purpose as the rear tyre normally wears out quicker so the add a bit of extra rubber to compensate? clever eh?

    Premier Icon tomaso
    Subscriber

    Not sure how high tech you think tyre making is?

    really? thats insane! surely manufacturing processes are not that vague? what about bike frames? wheels? the 11g difference is about 2.3% difference in weight. am I just ranting for the sake of it? lol is that what happens when you are nearly 40? arrgrghhh

    Try weighing all the bits on your car… Or even worse, measure its true BHP! Welcome to the world of manufacturing tolerances…

    andyrm
    Member

    2% tolerance is well within the realms of normal for any manufacturing process.

    Just put the heavier one on the back and do a few skids innit.

    Premier Icon njee20
    Subscriber

    what about bike frames? wheels?

    Absolutely! Massively so, 5% variance is very normal.

    xcretro
    Member

    So basically you could end up with two identical bikes that weigh as much as a pound in weight difference. Just goes to show it’s not all about the bike but the rider weight and fitness too.

    DanW
    Member

    Since you care about 11g this is a wake up call to hand pick all parts with the aid of your trusty scale 😉 that is the only way to be a true weightweenie! All components have 5-10% weight variation which becomes quite large when talking about frames, forks, wheels, etc. Tyres are particularly bad offenders since the manufacturing is far less controlled than you’d think. 11g difference is nothing on bonty tyres! Anyway why care about 11g on such heavy tyres 😉 Dirty Dan’s are probably the go to ww mud tyre

    Premier Icon stumpyjon
    Subscriber

    Tyre making is fairly hi-tech and automated, however most components in the tyre are extruded and the size of the extrusion is determined by the die but also extrusion pressure, temperature and speed. The cooling extrusion can also be stretched if the cooling belts don’t run at exactly the right speed.(also in my experience the SPC checks were used as guidelines rather than limits!).

    Premier Icon jameso
    Subscriber

    I know a guy who went through a pile of Mavic rims in a warehouse to pick out the lightest pair. Saved ‘loads’ apparently as they vary by 10-20g each.

    it’s not all about the bike but the rider weight and fitness too

    : )

    Premier Icon ononeorange
    Subscriber

    Is the tyre that weighed less than itself the one on the conveyor belt with the plane? They weigh less when filled with air – FACT.

    Premier Icon simon1975
    Subscriber

    Treat yourself to a fun day reading these pages:
    http://weightweenies.starbike.com/listings.php

    ste_t
    Member

    Weigh your tubes and put the lighter one into the heavier tyre and all will be right in the world.

    Or put more 11g more air into the lighter one.

    Premier Icon Northwind
    Subscriber

    stumpyjon – Member

    Tyre making is fairly hi-tech and automated

    Have you seen the conti factory vid? Their handmade in germany ones are squeezed out of a donut machine by a man with a beard. I’ve not seen the carcass making part but I imagine it’s a knitting circle of german grandmas.

    shermer75
    Member

    It’s because on a quantum level your Bontrager mud tyre is actually a pilchard

    Premier Icon njee20
    Subscriber

    Edit: well done, fixed!

    So basically you could end up with two identical bikes that weigh as much as a pound in weight difference.

    I’ve seen bigger variances between identical bikes than between different sized bikes – anyone who says “but it’s an XL”, it doesn’t really make much difference!

    I know a guy who went through a pile of Mavic rims in a warehouse to pick out the lightest pair. Saved ‘loads’ apparently as they vary by 10-20g each.

    I specifically asked Light Bicycle for a light pair of rims – they advertise them at 365+/-15g, mine are both 355g, so potentially 50g lighter than an identical set, why wouldn’t you specify that!?

    I’ve also gone through a pile of bits with scales and bought the lightest when I worked at the LBS and there was a choice!

    Premier Icon Northwind
    Subscriber

    OTher side of it though is that there can still be a tradeoff… Like, I remember a chap on I think it was MTBR, who said people were daft for buying lightweight tubes as they were too delicate, and instead recommended buying a tube that was supposed to be heavier, but finding a light example of that tube- as if the design-weight was more important to durability than the actual weight.

    I specced a heavier lightbicycle rim because they say they’re stronger.

    nickhart
    Member

    Firstly, you weigh stuff? Secondly are you bothered about 11grams? Personally I think I’ve sneezed more than 11 grams! As the stw massive above have mentioned manufacturers tolerances will have a large impact.

    mrmo
    Member

    Firstly, you weigh stuff? Secondly are you bothered about 11grams? Personally I think I’ve sneezed more than 11 grams! As the stw massive above have mentioned manufacturers tolerances will have a large impact.

    why not, 11grams on every component on a race bike soon adds up. As for the it’s the rider not the bike, exactly, if the rider thinks that they have a light bike it plays well in your head.

    If your idea of a ride is parking the A4 doing a lap of the carpark before going to the café, weight isn’t really an issue.

    Premier Icon hudders
    Subscriber

    I remember a story about Greg Lemond going through all the boxes of parts to build the team bikes and finding the lightest ones of the same parts, I think he said that you could find a big difference over a whole bike, I’m sure team Sky does the same with their marginal gains.

    Premier Icon DirtyLyle
    Subscriber

    OP, I have nothing useful to add other than the fact I always read your name as ‘excreto’. Am aware this says more about me then you. Sorry.

    My DMR vaults were about 10% over the claimed weight. That’s not a ‘manufacturing tolerance’, it’s a blatant lie! The dirty scoundrels…

    sbob
    Member

    Step one: throw away your scales.
    Step two: enjoy life.

    clubber
    Member

    I’m far more surprised that people would expect tyres to have less than 11g of variation (especially as I’m sure there’s actually a good bit more variation than that) than I am by the 11g difference.

    Manufacturing isn’t that consistent (or at least not at the sorts of prices we’re willing to pay) though it will depend on the specific product and manufacturing technique as to how consistent it is.

    Premier Icon njee20
    Subscriber

    I specced a heavier lightbicycle rim because they say they’re stronger.

    Which makes sense if it’s extra structural material, the risk is that it’s just extra resin, which doesn’t do much!

    Mine are probably full of voids mind!

    clubber
    Member

    They’re unlikely to be significantly stronger unless they actually put more carbon in. Surely heavier carbon is usually just going to mean more resin which isn’t the strong part (assuming that the carbon sheet is reasonably accurately cut to templates)

    (and conversely, as njee points out, lighter could mean not enough resin…)

    ndthornton
    Member

    I remember a story about Greg Lemond going through all the boxes of parts to build the team bikes and finding the lightest ones of the same parts, I think he said that you could find a big difference over a whole bike, I’m sure team Sky does the same with their marginal gains.

    Whats the point – you would have to add the difference in ballast anyway to meet the minimum weight (wouldn’t you?)

    so you would end up with a weaker bike and more ballast

    clubber
    Member

    Well there was no minimum weight in Lemond’s day. Bikes were fairly heavy then by today’s standards 😉

    Not the same for Sky, of course.

    Premier Icon njee20
    Subscriber

    Whats the point – you would have to add the difference in ballast anyway to meet the minimum weight

    Weight limit only introduced in 2000, and in Lemond’s days bikes weren’t in the 6.8kg range anyway.

    Edit: beaten by Clubber!

    ndthornton
    Member

    Are yes – was referring to team Sky

    klumpy
    Member

    jam bo
    2% tolerance. I think your being a big picky.

    “you’re”.

    DanW
    Member

    I remember a story about Greg Lemond going through all the boxes of parts to build the team bikes and finding the lightest ones of the same parts, I think he said that you could find a big difference over a whole bike, I’m sure team Sky does the same with their marginal gains.

    This isn’t anything too uncommon and certainly not limited to SKY. Most are passionate about the parts and the riding. Christophe Sauser is a prominent Weightweenie that springs to mind, given a lot of freedom to spec components and use custom parts openly and obsessively select the lightest components. If you want to see what the latest and greatest light stuff just about to appear on the market is then Sauser’s bike isn’t a bad start.

    There is quite a variety of approaches though… Some of the top XC/ road racers have surprisingly poor component knowledge or interest in bike parts. I guess partly due to having very little choice due to sponsorship and also perhaps mainly due to viewing the bike as a tool (with the training being the thing they are obsessive about). There is even less scope in the road world as a lot of the time they are adding weight to hit the 6.8kg limit. In the case of SKY, a lot of the stuff they are using is completely custom (to be stiffer, lighter or both) but made to look the same as the production stuff. Same goes for other teams and many will have custom layups on frames adding a lot of weight, completely custom shoes etc etc. Most of the stuff the pros use isn’t what it appears!

    DanW
    Member

    Oh… and a further tip to the OP: Don’t ever buy anything Italian based on the claimed weight or you’ll likely have a fit. Selle Italia saddles would be a good thing for you to avoid in particular 😉

    Premier Icon Northwind
    Subscriber

    njee20 – Member

    Mine are probably full of voids mind!

    Nancy says those are not voids, they are SPEEDHOLES!

    TBH I’m slightly skeptical whether mine’s genuinely heavy by design or they just have wild tolerances and throw them into a heavy and light pile but if I bought the lightest version and broke it I’d feel a bit silly.

    Premier Icon wwaswas
    Subscriber

    Didn’t Stans used to charge extra for the lighter versions of the same model? They guaranteed they be less than Xg and just weighed all the rims and picked out the ones that met the criteria?

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