Ask Pinkbike: Rotor Size, Convertible Helmets, and XC Shoes for DH
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.
Big Guy, Big Rotors?
Question: @Blacker6 asked this question in the all-mountain, enduro, and cross-country forum: I'm a big eighteen stone (252lb) lump and I'm thinking of switching to 203mm rotors. Any thoughts?
 | Larger rotors provide more power and less fading due to the added leverage and material, and while you didn't specify what type of brakes you have, I'm willing to bet that a guy of your stature would only benefit from using 203mm rotors. That's pretty obvious, but you can also use rotor size to tune how your brakes feel. For example, I weigh 160lbs and don't need 203mm rotors when using Shimano's all-powerful four-piston Saint stoppers - the big rotors don't just provide a boat load of power, but also make the brakes a bit too touchy for my liking, especially if the trails are wet or extremely dry and dusty. But if I'm using a two-piston brake with less power, or a cable-operated disc brake, a larger rotor can help a lot. Moral of the story: big rotors are usually great for big guys like yourself, but not necessarily better for everyone. |
Four-piston calipers and big rotors can supply a ton of power and initial bite, but that's not always a good thing.
Sweating in a Giro Switchblade?
Question: @Minikeum asks in the All Mountain, Enduro & Cross-Country forum:Any feedback on the new Giro Switchblade helmet? It looks safer than other convertible helmets. Better coverage, and downhill specific certification. I'm concerned about sweat. The pads of my current helmet get filled with sweat, which ends up dripping on my sun glasses. And it is really annoying. So I'm looking for a better new helmet. Note that I don't care about the look: I am a joey, and I'm proud of it. Safety is my biggest concern.Thank you!
| The Switchblade is definitely warmer than a traditional half shell, even with the chin bar removed. That's due to the extra material over the ears, and the fact that the vents aren't quite as large as what you'd find on a more XC-oriented helmet. That's one of the tradeoffs that comes with the increased level of protection, although it's one that plenty of riders are willing to accept. As far as sweat dripping into your eyes, I wouldn't say that the Switchblade is particularly prone to that issue – the padding does a good job of wicking moisture away, even on hot summer days. I've found that it's the area around my ears where I notice the extra warmth – there's not a lot of airflow reaching that area when you're grinding up a long climb. Otherwise, I've found the Switchblade to be very comfortable in both half shell and full face mode, and that extra coverage does help provide a little extra piece of mind when dropping into nasty terrain. |
The Giro Switchblade is warmer than a regular half shell helmet, but not nearly as warm as a traditional DH full face would be.
Disco Slippers for Downhill?
Question: Pinkbike user @ridedh10 asked this question in the Downhill Forum: Does anyone use a very stiff XC racing clipless mountain bike shoe for DH riding? I've tried the BMX/DH shoes from Shimano but they just aren't as stiff or as nice fitting as an XC race shoe, just wondering if anyone else likes such a stiff and tight fitting shoe for DH? I wonder why more pro DH riders don't do this (or do they)?
| I think there are a few reasons why riders don't use XC type shoes for downhill: fashion, function, and sponsorship. Downhill is a very fashion orientated sport; the proof is in the pudding with the "no lycra or tight fitting clothing rule" from the UCI. Riders wanted to keep the sport looking 'moto' and avoid riders donning the lycra (even though it will be faster down the hill, of course). When it comes to footwear, most downhill riders seem to look for a more skate styled shoe, something that they could wear to an after race party without looking out of place; the general fashion-led consensus towards XC shoes is a glaring, "No way am I wearing those disco slippers!" Performance wise, the amount of pedaling in downhill is minimal compared to the time spent spinning circles on a cross country bike. I remember reading years ago that Scott Sharples, who was the Australian team coach, calculated that the average World Cup downhill race comprised of eight, five-second sprints. So there is a marginal performance benefit to be gained from the power transfer of a stiff soled shoe. Personally, I prefer a softer shoe for downhill as it absorbs bumps better. I notice a huge difference moving from clipless shoes to flat pedals - put the flats on and suspension performance feels like it has improved instantly. Off the bike, a softer skate style shoe makes clambering up and down gnarly downhill tracks during practice easier, as well as hanging around the pits or the top of the hill for hours on end waiting for start times to arrive. Sponsorship and the resulting consumer's choices cause riders to choose a downhill specific shoe. If riders see Aaron Gwin shredding with his Giro Chamber shoes, for example, then riders and fans will want the same, regardless of what is best for them. If brands can create shoes for different disciplines, this widens their marketing and sales potential. At the end of the day, it's a personal choice. Try out as many options as possible and choose what you feel most comfortable in. |
Aaron Gwin racing in Fontana last weekend. We assume he rides in these Chamber shoes because he likes their performance for downhill. We also assume Giro pays him to wear them. Giro assume because you like him and he rides like a boss, you want to wear the same as him. Then you buy them and hopefully enjoy the ride characteristics he does.
Have some unresolved tech questions? Jump in the Pinkbike Forum and we'll look to answer it for next time.
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actually small rotors on DH bike = worn your rotors quickly + waste of 2 sets of pads quickly....+ generate enough heat to light a FKing fire....
Consumerism in a nutshell.
Main reason against wearing XC shoes for DH is the cleat mounting holes are too far forward compared to a gravity shoe. My calves are much more tired after a DH section when wearing my Giro Codes compared to 510 Impact2 Clips on the same trail and the same bike.
In my experience they last ages so I wouldn't mind stumping up the cash. My original M110s were nine years old when I gave them away!
Also now my instant mental association when I look at this helmet with its chin bar off.
I also have a Giro Switchblade, and it ROCKS! In addition to being perfect for the kind of trails I like to ride, I use it without the chin bar for BMX and urban freeride around Seattle.
"Ok, no one goes home until we have another new rule. Any suggestions?"
"Let's ban the skin suit for a change."
"Allright, good enough. Weekend!"
If there is no situation in which wearing one kind of mtb kit in the wrong situation will get you mocked, then in what sense is this a fashion oriented sport?
It's like watching Charlie Brown trying to kick a football.
store.haloheadband.com/elastic-sport-headband-p/hp.htm
I may have to try this, because it will change everything if it keeps the sweat out of my eyes and off my sunglasses!
Lost my halo band, used to need it with my Fox Flux but find I don't need it with my TLD A1.
@cgdibble: yeah little sweat spots on the glasses sucks.
As opposed to 'a piece of mind', which is what my wife is always giving me.
Small rotors, 4 piston brakes or large rotors 2 piston brakes?
and the difference between the 203 vs 180 rotor is about 30g (magura storm sl) so it seems like weight wise, 2piston with 203 vs 4 piston with 180, the weight would be almost the same. within 15g or so. But I havent yet tried how the second option (4piston w. 180 rotor) actually feels as far as the braking performance... but it might be worth a shot.
It does not take much to bake a small disk/caliper setup for me.
Now my daughter is a feather weight at 85lb I took the 203's on her bike off and put on 160's front and rear with two piston Elixer's and its great for her. Good feel (could be better), light enough and they don't glow red at the bottom of the mountain like that set up would for me
You may have to go thru some experimenting to find the balance between budget, feel, heat and how long they last for yourself. That said, I would guess your more the 140lb range and if your DH oriented 4 piston 180/160 would be a good starting point. It will also depend on how you brake, your mix of rideing etc etc
I've never noticed the initial bite being a problem - at least not yet. From where I'm sitting, the more brake power the better, since your hands will be less worn out after a few runs in the park.
M8000, ya that could be upgraded and I am sure you would be much happier if you do.
May I suggest Avid Guide brakes
Just from my research anyhow....
If you do change from Shimano to Avid make sure you get new caliper adaptors (post to IS or whatever your bike needs) Shimano have a different angle they hold the caliper than Avid, they look right but you can get some bad brake squeal if you don't do that.
got brake control skills fit 203s
pick a rota size and be a dick ????