Light weight innertubes

I was thinking that a quick and cheap way to shed some weight in the right place (rotating) for the selkirk merida would be to get some light weight innertubes.

Anyone use them regularly?
Am I cursing myself with 88km of punctures?
Any tubes to recommend, are latex worth it?

Any other quick cheap weight saving I could do?

It's not going to save much weight. How about new tyres?

Was given some latex tubes by mistake once. They lasted a couple ofrides but pinch flatted. when they do this they explode completely so can;t be fixed. Don't bother. Get a Stans kit and go tubeless with standard tyres. Or even cheaper do the same thing with 20" shwalbe innertubes. I saw a link to a great website explaining the whole thing. Can't find it but it looks like a great DIY method!

Tubeless will save you rotating weight and improve the grip of the tyres.

I thought the same and got 4 punctures round the MBR at cyb today.
Don't bother

I found this link it looks OK but can't see how it saves any weight?
http://www.tubelesswheels.com/als_half_tubes.html

That's the one bear-uk!

The whole 'saving rotating weight' thing is cobblers anyway; it's only of importance during acceleration, and the acceleration seen on your average mountain bike ridden by your average mountain biker is negligible to say the least.

Err, I'm definately not doing ghetto again, it didn't work out for me.

If saving weight only works when accelerating then surely it is most important on you rims, tubes tyre as they are always accelerating?!

Lighter tyres isn't really an option. I've got four pairs in my garage so I don't want anymore. Light tyres always seem to lack grip anyway as they are for racing round xc circuits, the ones I have on are fairly light anyway compared to most.

I guess there's not much point with the lighter tubes by the sounds of it.

crikey – Member

The whole 'saving rotating weight' thing is cobblers anyway; it's only of importance during acceleration, and the acceleration seen on your average mountain bike ridden by your average mountain biker is negligible to say the least.

Sorry, but that's rubbish.

Light tyres always seem to lack grip anyway as they are for racing round xc circuits

XC circuits are at least as demanding as the Selkirk Merida…learn to ride them!

If saving weight only works when accelerating then surely it is most important on you rims, tubes tyre as they are always accelerating?!

Er, no! Well at least not in a direction that required any power input to keep them rolling.

Only go for light tubes if you like fixing punctures – I made that mistake once, and once only – now run tubeless (proper Stans rims / Eclipse strips, which do work a lot better than ghetto).

Sorry, but that's rubbish.

Do expand. Numbers would be good if you're claiming that acceleration makes a significant difference to power requirements.

Crikey has a point though, to the average weekend warrior, the difference between latex and butyl inners isn't worth the hassle, neither's tubless IMO, but that's a whole other thread…

I ride similar-ish bikes one with trail wheel/tyre/inner set up and two with light weight wheel/tyre/inners, might be in my head but seem to move quicker off the mark, change speed faster, turn faster, lift faster and puncture faster. Heavier set, seem to take more to get up to speed, more to turn, but more momentum over (through) stuff and more time without punctures (especially pinch). On racing cars and 'real' bikes un-suspended weight and rotating mass make huge differences…..

We had latex inners for racing for years, until the 'supersonic/featherweight' ones came out. We had very few punctures, the latex seems to give more and not hole to the sharp things I would pull out of the tyre casing each week. But if they pinch punctured that was it. And they needed pumping up each week….

aracer – Member

Sorry, but that's rubbish.

Do expand. Numbers would be good if you're claiming that acceleration makes a significant difference to power requirements.

You come up with the numbers.

Are you telling me throughout a ride/race you are not accelerating/decelerating many times? Is your power output constant? Have you ridden the same bike with lighter wheels? etc etc.

(I'll presume you understand that accelerating the tyre/rim takes more energy than mass on the frame…if you don't then I give up)

Are you telling me throughout a ride/race you are not accelerating/decelerating many times?

Yes, but the power put into acceleration is insignificant compared to the power used for everything else. The reason I asked for numbers you see is that if you can't produce them (and throwing it back to me suggests you can't) means you haven't thought about it in sufficient depth, given that like a lot of bicycle science it isn't "common sense".

I'll presume you understand that accelerating the tyre/rim takes more energy than mass on the frame…if you don't then I give up

Do you realise just how insignificant saving 100g on a rim or tyre is in the grand scheme of things? If not I give up.

if you doubt that saveing weight in the wheels has any effect, why are we not all riding round on halo combats shod in 2.7 michelin comps (which in their super puncture protecting, seel beaded guise were well over 3lb IIRC)?

Loosing 1lb from the rims (i.e. the weight of a have tube at each end, or a chunky tire to a lighter one) will gain you about 1.3% greater acceleration, now given that loping 4lb is easy off heavy DH wheels to a trail ones, and another 2lb to light XC wheels, thats a lot of acceleration!

Is also going to make the bike handle better with less gyroscopic effect from the wheels.

As for which tubes, if you not tubelesess which is the best bet for sheding weight, dropping some roling resistance and improving grip. Then conti do normal rubber tubes that are as light as their latex ones. Had no more puncures with those than with their normal ones on the road bike.

selkirk merida is not light weight tube friendly ….. Experiance talking here …..

Did not get on well with joes no flats (despite having mates running them no bother) going to try stans 355 rims next…

<Puff> Well there goes your strawman, tinas. I didn't realise we were talking about going from DH wheels and tyres to superlight wheels and silly light tyres. Of course in reality riding round on big heavy tyres will actually cost you far more energy in extra rolling resistance than they'd ever cause in energy loss when accelerating. Meanwhile if jonb has standard inner tubes at the moment rather than downhill ones, that's only actually 100 to 150g to be saved, so less than 0.25% to be gained in acceleration. Not to mention that you get half that acceleration gain by saving weight anywhere else, with the bonus that you get exactly the same gain saving weight elsewhere as saving weight on the rims when climbing, which we spend vast amounts more energy doing than accelerating.

i was only taking it to its logical concusion :roll:

theres a study (by shwabble) on tire widths somewhere out there on t'interweb, wider tires actualy roll better off road, so for the same compound and tread you may as well go winde if you think weight isn't an issue.

I'll stick to tubeless of road and 50g butyl's on it.

back to the topic: maxxis flyweights are fine, 93-95g on average. I've been running them for some years. Obviously they tend to get holes faster than thicker tubes (maxlights or ultralights? the ones that weigh 120-125g) but installing new and checked tubes before a race helps. They can have holes straight from the factory.

PS we don't have any rocks here, only roots and glass roots and glass.

Anyone use them regularly?
Am I cursing myself with 88km of punctures?
Any tubes to recommend, are latex worth it?

aye, no, and yes. I use AirB but I'm not sure you can still get them anywhere.

Obviously they tend to get holes faster than thicker tubes

Which rather negates their point IMHO.

Lightweight tubes will drop 100g per wheel, and I dont find they puncture any more than a normal tube (OK DH tubes would be stronger)

There are loads of makes availiable but try to stick with the standard rubber as they patch the easiest when you do puncture.

conti supersonics or something is a fair bet… not sure how much the nutrak butyl ones on CRC weigh in at but at a fiver they are reasonable price.

If you can save 100g per tyre on your next tyre choice too you have just saved 1lb all off the wheels…

IT DOES MAKE A DIFFERENCE..

Obviously they tend to get holes faster than thicker tubes
Which rather negates their point IMHO.

Well, for this season I've got only two snake bites and no punctures from broken glass. Last year two snake bites (both of them very stupid ones, landed on a railway rail) and again no punctures from broken glass. Quite consistent results for the pressure I run (30-ish psi) for a 80 kilo person.

I run Laltex in my DH bike, no issues so far, and I've beaten the crap out of them. keep them inflated and they are fine, way better than light butyl tubes.

I've run lightweights mostly exclusivly for about 4 years now, so far i've only have 1 snakebite at afan, but the tyre was a little soft, and 3 puntures from things going through, 2 x glass on the road and a thorn – i'm pretty sure that if anything is going to be sharp enough to get through your tyre it'll go through an extra .2 mm of rubber, so lightweights get my vote, to be fair thou i don't know if i'd put them on a bike with more than 4 inch of travel thou, as your more likely to be seated over the rough stuff and pinch flat.

Exactly shoefiti, the differnence in thickness is .4mm if a something sharp is going into the tyre, chances are it going to puncture wether its an thin tube or a normal tube.

If you have gone to the extreme and are running 350g tyres and 100g tubes then you cant be doing the low pressure bit as its going to pinch flat, but with normal tyres around the 500g mark and decent volume I still get to run reasonably low pressures for comfort and grip and still dont puncture loads.

Maxxis flyweights here, on all of my bikes including the road bike, in the dry I run them with lightweight tyres (rear semi slick) at Afan, Cwmcarn and the local Bristol trails and I get no more punctures than normal tubes.

The weight saving does make quite a lot of difference.

Lightweight inners = more punctures!
I know, I tried for about a year, and I've switched back from the Spec' lightweight jobbies as it's a false economy.
Plus my bikes 2x weigh about 26lbs, so the weight saving is …. not worth the ink on this page to be honest.

I tried lightweights and bike felt noticeably snappier. But I pinch flatted them quickly and they didn't repair well. Ghettoed now. Not really lighter than tubes except I think you can get away with slightly skimpier tyres.

Given that the average mountain biker weighs about 80kg, and the average bike weighs about 13 kilos, plus the weight of baggy shorts, flappy top, Camelbak weighing 500g, water weighing 2kg, all that extraneous stuff that people 'need' to carry, say another 1.5 kg, plus helmet, specs, socks, shoes etc, giving an overall weight of about 100kg, all of which has to be subjected to the furious accelerations we can all manage, isn't it likely that lightweight inner tubes will have exactly no discernable effect at all?

If you want the cheapest way of saving weight, stop carrying 2 litres of water all round the countryside and chuck all that crap out of your camelbak, then wear lycra instead of baggies.

crikey – wise words indeed!
It's similar when I go on long treks around the world – the stuff people take with them defies beilef. Hard backed books, family sized bottles of shampoo & sun screen, you name it.

I noticed no difference with lightweight tubes 'cept they puncture more readily.

Well, for this season I've got only two snake bites and no punctures from broken glass. Last year two snake bites (both of them very stupid ones, landed on a railway rail) and again no punctures from broken glass.

That's 4 more than me in that time then – anyway it was you who said they got holes in more easily. If you're bothered enough to want to try light tubes, you should be bothered enough to run tubeless instead.

Oh, and I agree totally with crikey. I carry far less of that sort of rubbish than most people do, yet I seem to be the one arguing against light tubes (to be fair I do have much the same weight as a light tube, just that my weight consists of tape, valve and sealant).

Try adding a 2kg of lead weights to your bike and report back whether you notice it. I bet you do.

Isn't the force you must apply equal to the mass*accel? So if mass goes up, so does the force required to get moving = hurty legs. Think of your wheels as very light flywheels – heavier ones are slow to take up energy (motion) but good at keeping it (momentum). I imagine whether one is sensitive to small changes of rotating mass varies between people and how stop/start their riding is.

I agree on people carrying a bag full of useless crud around tho. But there is a minimum of stuff you need to deal with common bike failures. £10 note is light though and buys lunch rather than carrying a big box of sarnies. I do have a tip – buy a small bag – if forces you to pare down your stuff to the minimum.

Try adding a 2kg of lead weights to your bike and report back whether you notice it. I bet you do.

<puff>

I imagine whether one is sensitive to small changes of rotating mass varies between people and how stop/start their riding is.

Or maybe just how susceptible they are to the placebo effect.

Good analogy, re the flywheels.
Light tubes will make 'a difference' but whether it is discernible is another matter.

I would never make a change like that for a race. Better to do it 1 month before & try it on the trails before accepting or rejecting the change.

It never ceases to amaze me the amount of people who seem to run light tyre/tube combinations to save 5secs per lap & then spend 5 mins replacing a tube after puncturing during a race. At the Wiggle Enduro6, there were people with punctures left right and centre, but I couldn't see anything to puncture on. Similar story at the Thetford races.
I'd rather have a more durable set-up and be confident that in the latter stages of a ride when my technique is perhaps a bit lacking and I clatter stuff due to tiredness that I am not going to puncture.