Here at Pinkbike, we get inundated with all kinds of questions, ranging from the basic "Can I have stickers" to more in-depth, soul-searching types of queries like if you should pop the question or what to name your first child. Ask Pinkbike is an occasional column where we'll be hand-picking and answering questions that have been keeping readers up at night, although we'll likely steer clear of those last two and keep it more tech oriented.
Why Can't I Run Lower Tire Pressure?
Question: Thegb1212 asks in the All-Mountain/Cross-Country Forum: I have a 30mm inner width rim and [Maxxis] 2.4 EXO casing WT tires mounted up tubeless. If I even think about running lower than 27psi, my tires will start to fold over and squirm all over the place. I am not burping at those pressures, but the squirm is not confidence inspiring. I am also only 165lb. It doesn't make sense to me how folks can run pressures in the low 20s with a 'standard' tubeless set up. I am talking about non-fatbike, no Plus, just plain old 2.2 to 2.6" tires. So tell me, how can RC comfortably run 24/22 psi on 2.3" ? What am I missing? Don't get me wrong, I love the minimal flats, lower weight, and less fuss I have had with tubeless, but lower pressures aren't one benefit that I have found is possible.
Good question. Tubeless tire pressures in the 22 to 25 psi range are not considered low, even by aggressive riders. The pressures I use are representative of most of us here at PB and the top guns I associate with on my home trails. Your combination of a 2.4-inch Maxxis WT tire with an EXO casing on a 30-millimeter rim should be plenty stiff above 25 psi, but that does not mean that you are wrong if you need more pressure to keep your tires stabilized on your rims.
Every tire and rim combination has a pressure sweet spot where the lines intersect for casing stability, traction, and suppleness. Physics dictates that larger volume tires require less pressure to achieve the same casing stiffness, and that wider rims improve lateral stability, but riding and pedaling style can trump that science.
I also weigh 165 pounds, but my riding style is such that I don't exaggerate my lean angles in the corners or put much lateral force into the frame. Some riders do, which requires stiffer casings and higher pressures to counter that off-center tire loading. You are not burping air, but still feeling tire squirm with your present rim and tire combo which suggests that you are one of them.
Before you consider purchasing new tires with thicker casings, however, be sure that your tire gauge is reading correctly. One of my floor pumps reads over four psi high, which indicates that I am running pressures around 27 to 30 psi. Now I use a Schwalbe digital air gauge to ensure accuracy. Borrow a good gauge and verify your pressures first.—RC
An accurate digital tire gauge, like this Topeak Shuttle, should be in every rider's tool box.
Best Hip Pack for Shorter Rides?
Question: @jkelm asks in the Bikes, Parts, and Gear forum: Looking for a hip pack to take on 1-2 hour rides. Ideally it will hold a water bottle, with enough room for my phone, keys, multi-tool and misc small items. I've looked at the Dakine Hot Laps, best curious if there are any smaller or better options out there?
Hip packs are most definitely back in fashion – just ask Lil' Wayne. He's been making the talk show rounds in support of his new album while wearing one, although its contents might be a little different than what you'd want to bring on a long ride...or maybe not.
In any case, Bontrager's Rapid Pack remains my favorite method of carrying a few tools, snacks, and a water bottle. It doesn't shift around, there are internal dividers that help with organization, and the water bottle holder is where it should be, in the center, rather than off to one side. If you already have a bottle on your bike, that center pocket is the perfect spot to stash a lightweight jacket or glasses / goggles. The fabric is fairly light, but after over a year of regular use my pack is still going strong. I'd highly recommend checking one out.— Mike Kazimer
Bontrager's Rapid Pack is one of the best options on the market for carrying the items needed on a short ride.
Michelin Le Systeme?
Question: @ORTOGONAL555 asks in the Downhill Forum: Hello everybody. I've recently discovered that Michelin developed a run flat setup called "Le Systeme" for DH racing at the end of the 90s~early 2000s. I'm just curious about it and I can't find more about it on the internet. If anyone has info please chime in, thanks.
There's a good reason why you cannot find out any information about 'Le Systeme,' and that's because it was one of the most secretive things in downhill racing, ever. Fables of riders and mechanics signing non-disclosure agreements and never being allowed to look inside, Michelin mechanics delivering the wheelsets fitted with tires and inflated to racers the morning of the race, and taking them away as soon as they were back in the pits, have circulated for years.
From the rumors I heard, there were three possibilities, one was that it was some kind of inner tube wrapped in foam, similar to things we have seen come back on the market recently: Tannus and Vittoria launched their 'Armour' system last week, and earlier this year, Mr. Wolf launched their SmartMousse. Both use a similar concept, the Tannus version uses a larger inner tube with a small volume of foam for protection, and the Mr. Wolf version uses a small diameter tube to adjust the feel and density of a larger volume foam - mostly aimed at eMTB riders, partly due to its 500g+ weight.
The second possibility is that Michelin used some kind of run-flat foam/mousse (mousse is the French word), like they used on rally cars. The foam was mounted on to the wheels and compressed when the tires were inflated to keep the characteristics of the tire the same as there was no material touching the carcass of the tire. If air was lost from the tire, the reduction in pressure allowed the foam expand, filling the tire, supporting the weight of the car, and keeping the tire on.
The third throws an extra spanner, or valve, into the works. Some people claim to have spotted an extra valve on the wheels, and there was talk of a tubular tire being placed inside the main tire, which was protected by foam. A similar idea to Schwalbe's ProCore System that that does a great job of locking the tire bead on to the rim even if the external chamber loses air, and protecting the rim from damage with its high pressure 'inner tire'.
I reached out to Michelin, and Mavic, who played a part in the project with their DeeMax wheels, and even though it's been well over a decade since it was last rumored to be in use, they still replied with a strict "no comment."
The 'Armour' tube from Tannus and Vittoria could be a modern-day version of the Le Systeme from Michelin.
Mr. Wolf's SmartMousse is a similar concept, but with a larger volume of foam/mousse and a smaller tube to fine tune the ride feeling.
Combating Feelings of Dehydration on Rides
Question: @zachinblack asks in the Fitness, Training and Health Forum:I am one of those guys who can never have too much water on a ride. I drink water constantly, and always feel like I need more. I know I am drinking enough, as I don't cramp up on rides, nor is my urine bright yellow, but the feeling, sensation remains. My question is this: Is there a product that will help me retain more water and hopefully diminish this feeling of constantly needing more fluids? At this point, I'd love to just be less reliant on water and make less go further, so I can forego a hydration pack and just use my on bike bottle, and at most, my hip pack's small reservoir. Am I SOL, or is there something that could help?
I reached out to my good friend Colin Izzard, who is a coach with Carmichael Training Systems. Colin works with a lot of different athletes, including World Cup DH racers like Neko Mulally, and he suggests making sure that your everyday hydration is up to par. Starting a ride already "in the hole" is the quickest way to run yourself further into the ground. A minimum of two liters a day is recommended. If it's hot out and you're going to be doing a longer ride, increase your hydration beforehand and consider adding something that has some sodium to your water to help increase absorption.
While riding, you still have to drink water, so your idea of being less reliant on water may not be the best. You want to down 1-2 bottles an hour, and more during hot weather. When it's cold, don't forget to drink because it's still important. Ensuring you're getting 400-900mg of sodium/hour is also important to help keep you feeling good.
After riding, continue to drink water in order to replenish what you've lost. Keep up with the sodium, and a carbohydrate drink will help recovery too. Nutrition is equally important in combating feeling off, and you should always have a solid meal before riding, and try to get 200-300 calories/hour while riding.
That's a few hydration tips in short and it's certainly person and situational dependent but hopefully it helps. One thing that I've found helps me to keep hydrated when I don't want to carry a lot of supplies on a ride and there is water nearby is to bring a water filter, such as Sawyer's Mini, and stop every hour or two to filter more water. I then supplement it with a sodium/electrolyte tablet. I've successfully done quite a few longer rides with this method.
As with any other health issue, if you're not sure or consistently feeling off, check with your doctor or dietician.—Daniel Sapp
Hydration pack can carry lots of water, but not everyone wants to ride with all that weight on their back.
Small enough to fit in your pocket and allows you to ride 'til you run out of food without having to carry gallons of water.