Are latex tubes more likely to fail at high speeds/braking at high speeds?
Living in the flat midwest, I dont have (m)any places where I am going 40 mph+ downhill.
Upcoming race has a long high speed downhill and somewhere in the recesses of my mind I feel like I heard about latex tube failures.
Can someone set me straight?
Thanks!
Never had a failure while in use (other than two punctures, which isn’t what you are referring to)
Local roads include technical 20% decents, and long 10km+ 6-10% descents.
Rider mass 82+kg and speeds over 70km/h
I had heard the concern was rim brake carbon clinchers + latex + lots of braking → building up heat on the rim. https://www.velonews.com/gear/technical-faq-tape-for-tubulars-latex-tubes-and-more/ talks a bit about different manufacturers perspectives on the issue (it’s a bit of a mixed bag, Challenge says don’t, Vittoria says it’s fine)
If you have disc brakes (or non-carbon braking surface wheels), I guess this is all a moot point.
Don’t know if this is just a myth or what. Neither me nor anyone in my group has had a latex failure from overheating. I’ve gone down some 1000+ft 10% descents at speed and 85kg+
I had heard the concern was rim brake carbon clinchers + latex + lots of braking → building up heat on the rim. https://www.velonews.com/...atex-tubes-and-more/ talks a bit about different manufacturers perspectives on the issue (it’s a bit of a mixed bag, Challenge says don’t, Vittoria says it’s fine)
If you have disc brakes (or non-carbon braking surface wheels), I guess this is all a moot point.
IIRC ENVE also warned against latex for it’s rim-brake models. That being said, there are TONS of folks racing with carbon rims/latex tubes (and have been for years) and when’s that last time you heard of a latex tube blowout on a descent? The issue seems much more theoretical than practical (think of all the folks who run carbon/latex on the Kona course coming down from Hawi, or those doing Lanzarote)… Sure a 300lb guy descending Alpe d’Huez with his brakes on the whole way might be able to produce a failure, but we’re talking edge cases.
Latex can explode while using rim brakes. I ride latex with rim brakes exclusively. I weigh 94kg and descend big mountains and ride fast. Never have had an issue.
Sold my wheel to a client who rides tentatively and probably drags brakes the whole way down long descents because she’s not comfortable much over 30-35mph. She had the latex tube explode and ruin her new-to-her wheel, tire, and tube, much to my dismay. At those speeds, aero drag is not high enough to do most of the braking. When you’re up near 45mph, the air is doing most the braking for you, especially if you’re comfy changing position on the bike and sitting up a bit to catch more wind.
I suspect it’s not descending fast then braking hard that is the problem. It’s descending slowly by using your brakes constantly for minutes on end. Note to self: don’t sell rims with latex tubes to very cautious descenders.
To be clear, I have descended fast and braked very hard from ~50mph to 0mph, including some loss of traction of the rear wheel, on multiple occasions with no explosion issues.
Thanks all. I do have rim brakes and forgot to mention that. Oddly enough, even though I dont have big descents by me, I am comfortable descending and wont ride the brakes. (just did a trial descent in California at 35-40 mph and will practice again in Breckenridge in a few weeks)
Only time I hit the brakes is traffic lights and/or having to turn.
Creating a brake with my body is a good idea too when I need to be slowed.
Thanks!
Latex can explode while using rim brakes. I ride latex with rim brakes exclusively. I weigh 94kg and descend big mountains and ride fast. Never have had an issue.
Sold my wheel to a client who rides tentatively and probably drags brakes the whole way down long descents because she’s not comfortable much over 30-35mph. She had the latex tube explode and ruin her new-to-her wheel, tire, and tube, much to my dismay. At those speeds, aero drag is not high enough to do most of the braking. When you’re up near 45mph, the air is doing most the braking for you, especially if you’re comfy changing position on the bike and sitting up a bit to catch more wind.
I suspect it’s not descending fast then braking hard that is the problem. It’s descending slowly by using your brakes constantly for minutes on end. Note to self: don’t sell rims with latex tubes to very cautious descenders.
To be clear, I have descended fast and braked very hard from ~50mph to 0mph, including some loss of traction of the rear wheel, on multiple occasions with no explosion issues.
How did she know the latex tube exploded from overheating rather than the much more typical impact-related or puncture related flat? I’ve had more than a few unexpected high-speed pinch flats where there was nothing puncturing the tire casing (butyl tubes in my case.)
Latex can explode while using rim brakes. I ride latex with rim brakes exclusively. I weigh 94kg and descend big mountains and ride fast. Never have had an issue.
Sold my wheel to a client who rides tentatively and probably drags brakes the whole way down long descents because she’s not comfortable much over 30-35mph. She had the latex tube explode and ruin her new-to-her wheel, tire, and tube, much to my dismay. At those speeds, aero drag is not high enough to do most of the braking. When you’re up near 45mph, the air is doing most the braking for you, especially if you’re comfy changing position on the bike and sitting up a bit to catch more wind.
I suspect it’s not descending fast then braking hard that is the problem. It’s descending slowly by using your brakes constantly for minutes on end. Note to self: don’t sell rims with latex tubes to very cautious descenders.
To be clear, I have descended fast and braked very hard from ~50mph to 0mph, including some loss of traction of the rear wheel, on multiple occasions with no explosion issues.
Can you explain the mechanics of this? To have a blowout (“latex tube explode”), the tube has to be outside the tire/rim enclosure. That means that the air inside the tire had to be so hot as to push the bead off the rim and expose the tube. What difference would the tube material make at that point? Or do you think the fact that it was a latex tube enabled the tube to escape the tire/rim enclosure?
Not sure. Haven’t thought it through. Seems plausible that it could heat up substantially if dragging brakes on carbon rims for miles. Looked like a golf-ball-sized grenade went off inside the tire and rim. Totally mangled. She said the explosion noise scared her more than the loss of control of the bike.
I have had a total of 3 latex flats since I began using latex tubes in 2017. 1 flat was hitting a piece of debris that killed tire & tube. The other 2 were at the bottom of very steep descents when I was braking heavily. After the first, I was concerned about heat transfer because I had velo plugs with high-end aluminum rims and reduced barrier between tube and rim. The second was with rim tape specifically installed to reduce heat-related flat risk. It flatted the next time I did a mega descent.
In both cases, I could not find any obvious interior defects or causes in the wheel between tube, tire, and rim.They were on different wheels.The roads were perfect and clear.The wheels, tires, tubes had been used together for a few hundred miles of no changes and perfect use.The flat occurred at the very bottom of the hill with no event (bump, pot hole, road debris, etc.) associated with the timing.The common denominator was constant braking down a very steep and long descent.
Summary: I am abandoning use of latex tubes in my road bike on any ride with steep, long, technical descents.
think of all the folks who run carbon/latex on the Kona course coming down from Hawi
I honestly can’t think of a long descent that is less likely to cause problems of the sort under discussion than the one down from Hawi. I mean, to heat up the rims via braking friction, you’d have to actually need to use your brakes at some point…
Can you explain the mechanics of this? To have a blowout (“latex tube explode”), the tube has to be outside the tire/rim enclosure.
The mechanics of it are pretty simple. Melting point of latex is (iirc) right around 250f. Rim of wheel exceeds this temperature at a point where there is direct contact with tube, hole melts through tube, pressurized air escapes from hole and blows tire off rim.
I personally saw this happen more times than I can count racing MTBs back in the pre-disc brake era at events like the TransAlp challenge. Even with most folks on butyl tubes, as soon as the race hit the long paved descents that featured in this type of racing, you’d start hearing tubes cook off at the back of the pack from people riding their brakes too much. At times it sounded like someone was making popcorn.
Granted, it’s not a twisty alpine descent, but there are lots of folks who get uncomfortable past a certain speed and will constantly be scrubbing off speed vs. going full Sebi and treating it as a bombing run.
For rim brakes (regardless of type) some user discretion is needed to prevent heat related failures. Overbraking can cause clinchers to blow off the rim, and can melt tubular glue causing tires to roll off (ex. Beloki’s famous TdF crash).
Latex can explode while using rim brakes. I ride latex with rim brakes exclusively. I weigh 94kg and descend big mountains and ride fast. Never have had an issue.
Sold my wheel to a client who rides tentatively and probably drags brakes the whole way down long descents because she’s not comfortable much over 30-35mph. She had the latex tube explode and ruin her new-to-her wheel, tire, and tube, much to my dismay. At those speeds, aero drag is not high enough to do most of the braking. When you’re up near 45mph, the air is doing most the braking for you, especially if you’re comfy changing position on the bike and sitting up a bit to catch more wind.
I suspect it’s not descending fast then braking hard that is the problem. It’s descending slowly by using your brakes constantly for minutes on end. Note to self: don’t sell rims with latex tubes to very cautious descenders.
To be clear, I have descended fast and braked very hard from ~50mph to 0mph, including some loss of traction of the rear wheel, on multiple occasions with no explosion issues.
Same on boiling hydraulic brakes. It’s not the fast guys and gals who brake intermittently but hard - its the constant dragging brakers that put soooo much energy into the brake (with some finding it’s way to the oil).
Granted, it’s not a twisty alpine descent,
It’s not even in the same galaxy. The average gradient of Hawi is 1.8%, and it maxes out at <10. I’d honestly be surprised if even the most timid descender could over brake sufficiently to get enough heat into the system to have rim/tube problems on that descent.
Not sure. Haven’t thought it through. Seems plausible that it could heat up substantially if dragging brakes on carbon rims for miles. Looked like a golf-ball-sized grenade went off inside the tire and rim. Totally mangled. She said the explosion noise scared her more than the loss of control of the bike.
Aaah…good ol’ carbon clincher rims. The most likely scenario is that the carbon rim walls “softened” from the excessive heat dissipation, then deflected outward from the air pressure and tire casing tension, to the point that the tire bead was no longer able to hold onto the rim, at which point the tube “escaped containment” and exploded with a loud bang. The only way to get that noise is it failing outside the tire. There’s no physical way a latex tube can “explode” inside of a tire like a bomb. The noise was the result, not the cause, of the failure. A similar failure could happen with a butyl tube as well.
So, in the end, the issue isn’t latex tubes, descending, and riding the brakes, per se. The ISSUE is doing so on a carbon rim that a.) reaches higher temperatures than an aluminum rim under the same conditions, and b.) distorts at those elevated temperatures to the point the tire no longer is safely attached.
One thing that disc brake proponents have gotten right is that braking surfaces should be metallic. After that, it’s just an argument about how large the braking “disc” should be and if it’s integrated into the rim, or not 
There are (or at least used to be) plenty of deep, aerodynamic rims with aluminum braking surfaces…and they are typically within a handful of grams weight-wise of full carbon clincher rims. Making a rim-braked clincher rim completely out of carbon is one of the most questionable design decisions ever made in cycling.
…There are (or at least used to be) plenty of deep, aerodynamic rims with aluminum braking surfaces…and they are typically within a handful of grams weight-wise of full carbon clincher rims. Making a rim-braked clincher rim completely out of carbon is one of the most questionable design decisions ever made in cycling.
Completely agree!
And yet we regularly have threads with guys asking what full carbon rims they should buy, in rim brake applications. If they don’t even have specific wheels in mind, the fact they’ve already decided they must be full carbon is revealing. It’s all about marketing and perception, not logical analysis.
I been riding latex tubes since probably the mid 90’s. Never had one fail with a rim brake ever and I have done some long extended decent. I’ve ridden Brasstown Bald and Lookout Mountain. do fail when they get old so if I have one in a wheel two years it gets replaced. Also when I used thin butyl and would get many flats and know I’ve had possibly two in over 15,000 miles of riding. If they did fail would companies even sell them with our litigious society? Ride them and enjoy the less wattage and to me a noticeable deference in the ride.
I live in Midwest very hot area. Same latex tubes with GP5000 for two years now. No problem at all. I haven’t had a single puncture. I have a big race coming up in September so I’m thinking about replacing them. I started using them after getting advices from ST and I’m very impressed. Love them.