Ask Pinkbike: XC Bike Upgrades, Fork Offset, and Mid-Air Braking
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.
More With Less
Question: Pinkbike user ghettoflash asked this question in the 29ers forum: I have a 2014 Trek SuperFly FS 9 that has been a very good bike for myself, but I'm finding that I am riding it harder than it's been intended to be ridden. I've made some minor upgrades, but I'm looking to make it more aggressive. Here are my issues: the rear shock can't handle small bumps and chatter doesn't eat up the travel; the fork has the same problem as the shock; I'm too far forward on the bike and don't feel balanced on steep terrain. I've put on a wider, flat carbon handlebar, and a 120mm fork. This seemed to help a little.
Here are my proposed changes: the Monarch RL to either a Double Barrel or a Monarch RT3; SID RL damper to an RCT3; a half-degree offset bushing; swap the 100mm stem to a 45mm stem. These proposed changes are going to cost close to $500... is it worth it?
 | Doing a lot with a little is a subject that I'm very familiar with. I'm talking about bikes, of course, and my preference for riding a cross-country bike, or any short-travel bike, in settings that it's either not intended for or not expected to be seen in. To answer your last question first, spending money on a bike you love, regardless of how old it might be, is worth it so long as you plan on keeping it around for awhile. That $500 is a lot less than the thousands it costs for a new rig. The swap to a wider handlebar and a shorter stem at the same time makes sense (the wider handlebar will actually shift your weight forward), but I'd likely start with a 60 or 70mm and go from there. Those will both feel drastically shorter than the stock 100mm stem and don't forget that the bike's geometry was designed around a bit longer stem - shortening it up too much could make the handling feel odd and the front-end push. The bike's Monarch RL shock doesn't have a low-speed compression dial, and it probably has a pretty firm cross-country inspired tune that's more about efficiency than sucking up trail chatter. Even so, I wouldn't change out the fork or shock. Instead, spend less money on a set of high-volume tires and, if you really want to get the most out if the big rubber, a set of wider rims that will let you run the tires as low as possible. Doing this can completely change a bike's personality: its suspension will feel more forgiving over the chatter, it will handle better and have more traction, and you'll then have more confidence. - Mike Levy |
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A cross-country race bike with a short stem, wide handlebar, dropper seat post, and big tires can be a ton of fun.Will Two Millimeters More Fork Offset Change My Steering?
Question: Kellster99 asks in the All Mountain, Enduro & Cross-Country forum: I've got a good deal on a second-hand 2015 Giant Reign Advanced 1. It comes with a RockShox Pike RC DPA fork. The fork offset is 46mm, rather than the standard 42mm. I plan to upgrade to a Fox 36 in the future. Can I still put a fork on a bike with a different offset than the one it came with, and will it really make a noticeable difference?
| You probably would notice the change in fork offset between the 46 and 42 millimeter options of the RockShox Pike, but I doubt you will sense much change between the 44-millimeter Fox 36 offset and your present fork's 46-millimeter value. Both numbers are in the sweet spot for a 27.5-inch-wheel chassis with a 65-degree head-tube angle. If you were riding round-profile cross-country tires. pumped up to 35psi and spent a lot of time on hard-pack surfaces, that could be a different story. The wider, softer tires that most people use on a bike like the Reign, however, ensure that the small amount of trail increase will have a minimal effect on the steering because the tire's contact patch is much broader and thus, less sensitive to minor steering-geometry changes. If you do sense a difference, your front wheel might turn into the corners more readily as you lean the bike - but it would be a very subtle change - RC |
Cannondale reduced the Habit's trail by extending its "fork" offset to 50 millimeters in order to lighten its steering feel and make its cornering more nimble in tight quarters. Its head angle is 67.5 degrees with 27.5-inch wheels. It can climb and descend switchbacks with surgical precision.
The GeoMetron favors stability over nimble steering. Its 27.5-inch chassis uses a Fox 36 fork modified with only 40 millimeters of offset to further extend the ample trail of its 62-degree head angle. It can ignore just about any obstacle in its path. Tight switchbacks... not so much.
Braking in Mid-Air?
Question: Pinkbike user JustinLund asked this question in the Freeride & Slopestyle Forum: I've been watching a few videos recently and noticed that most people seem to always have their fingers over the brakes in the air - but due to the helmet cam footage (of what I've been watching, at least) I can generally only see this while they're in the air. Is it just common practice to keep your fingers over the brakes the entire time while riding? Or is there any specific reason they're covering them while in the air? Is there any reason to hit the brakes in the air?
| Having your fingers over the brakes in the air isn't about controlling the bike by grabbing them mid-flight; instead, it's done in order to be able to regain control the instant you touch down. You know, for those times when you come into a jump a little too hot, and need to slam on the brakes in order to avoid careening into that pesky tree looming just past the landing. Of course, it's not a hard and fast rule that you should have a finger over the brakes at all times. That's part of the beauty of mountain biking - everyone has their own style, and plenty of riders, especially those from a dirt jump or BMX background, wrap all of their fingers around the bars once they're airborne. Do what feels most comfortable, but I would strongly recommend against trying to rely on the brakes to change the bike's position in the air. Unlike on a motorcycle, where it's not uncommon to change the position of the wheels in mid-air by twisting the throttle or grabbing the brake, on a mountain bike it's best to change the angle with subtle shifts in body position, or by bending your arms to bring the front wheel up and towards you. Braking while in the air on a bike will bring the front end down, but it happens very quickly, and I'd say that in most cases it's far too fast of an action to be useful for anything except tossing you over the bars. - Mike Kazimer |
When he's not throwing suicide no-handers, Remy's index fingers are resting on the brake levers.
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........i alsohave a Cotic 27.5 bfe with 140front that is awsome trail rowdy hardtail! Probably the bike i ride most to be honest :-)
To be clear though, it's a correction for lack of technique, not a "pro move" ha
By all rider accounts, it's length and slack angles don't seem to hinder its tight cornering ability whatsoever. Which is it?
I hope to be back on a bike late November, and when I do, I will make a big effort to keep my fingers off those brakes in the air. There's definitely good reason to keep your fingers in the ready position, but in my case, I would have avoided many injuries if I stayed away from those brakes - er "breaks".
I disagree completely, a little feather af the rear brake can work wonders if you are starting to loop out, or the pedals are floating away from your feet (maybe thats just a flats thing) or even if everything is going just fine but you still want to drop your nose a little. Shifting your bodyweight mid-air does absolutely nothing to make you rotate forwards or backwards. Ask your physics teacher. The best it can do is prolong the inevitable. Often this is enough, but if not, those brakes sure can be handy.
"plenty of riders, especially those from a dirt jump or BMX background, wrap all of their fingers around the bars once they're airborne."
Umm, what? Gotta disagree there too. If a dirt jumper took their finger off their brakes every time they got airborne, they would be changing finger position every second or two. I don' t know a single DJ rider who does this...I haven't had brakes on my BMX in years. The one guy I know who does regularly pulls his brake mid air. You can hear it squeak when he does. Good dirt jumper too.
That is irrelevant, don't do any of such stupid shit until you can backflip crabapple bits. Focus on proper jumping form. Practice. Where to learn about it: leelikesbikes.com, Phil Khmetz youtube channel.
@gabriel-mission9: You can shift your balance in mid air just by leaning - just like cats rotate in mid air - using inertia. Get your bike sideways, turn the handlebars down and get the bike back into the vertical plane. The gyroscopic effect will bring your front wheel down.
I watched the Anthony Messere vid. Its kinda hard to see his fingers most of the time, but I kinda got the impression he kept his brake covered unless he couldn't, either through not actually having his hands anywhere near the bars, or shortly after having caught them, OR being contorted into such a shape that he simply cant reach it. I am perfectly willing to admit he may well ride death gripping at other times, but I'd bet if you rode with him regularly, you would catch him using his brake mid air sometimes too.
www.bikeradar.com/mtb/gear/article/pushing-the-limits-of-fork-offset-an-experiment-45343
Going from the RL to RCT3 front dampers was a great upgrade, make sure you get the compression and rebound dampers (~$200 IIRC). You don't have to get a new fork to go to 120mm, just put a 120mm solo air spring in your SID (assuming it's a solo air). $25 and see how you like it, or maybe 110mm?
Wide(r) carbon wheels might be on the upgrade list. I went to 22mm Inner width rims and I could tell over the stock skinny rims, but I'm not sure what the point of diminishing returns is there: 24mm? 30mm?
I don't know anything about rear shocks cause I ride a Hardtail.
Good luck with it.