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-   -   Steep Downhills on a CX bike (http://www.bikeforums.net/recreational-cyclocross-gravelbiking/949577-steep-downhills-cx-bike.html)

rekon 05-22-14 11:34 AM

Steep Downhills on a CX bike
 
So, I've commuting on a trail to work for the past few days. I am faster on the climb vs. my friends MTB.

But going downhill on this trail is scary as hell and I feel every vibration in my hands. How do you guys deal with this? Are CX bikes not meant for downhill trails?

gnawthrough 05-22-14 11:36 AM

lean back, stay in the drops and have your elbows bent. point and shoot!

Andy_K 05-22-14 12:11 PM

Define "downhill". CX bikes are most definitely not meant for what serious mountain bikers call "downhill". Neither are most mountain bikes. On the other hand, you obviously can take a CX bike down a hill.

If you're still worried about the vibration in your hands and not fearing for your life, it's probably OK.

rekon 05-22-14 01:01 PM

Quote:

Originally Posted by Andy_K (Post 16782550)
Define "downhill". CX bikes are most definitely not meant for what serious mountain bikers call "downhill". Neither are most mountain bikes. On the other hand, you obviously can take a CX bike down a hill.

If you're still worried about the vibration in your hands and not fearing for your life, it's probably OK.


Downhill = For a 10 mile stretch its about 400 ft downhill. The downhill is not constant and it's mixed with level and uphills.

I have to admit I did fear my life (or at least injury) a few times. I had to brake almost all downhill stretches. My disc brakes were screeching. Which reminds me I have to check my brakes because now I have to squeeze the lever hard to brake and the rear brakes are sketchy.

rekon 05-22-14 01:04 PM

Quote:

Originally Posted by gnawthrough (Post 16782428)
lean back, stay in the drops and have your elbows bent. point and shoot!

I was too scared to stay in the drops. I ended up being on the hoods for most of the time. I'll give the drops a try!

flargle 05-22-14 01:46 PM

Quote:

Originally Posted by rekon (Post 16782693)
I was too scared to stay in the drops. I ended up being on the hoods for most of the time. I'll give the drops a try!

Hoods are the worst place because you don't have a solid grip. Bar-top interrupter levers are great for steep descents because you have a solid grip and can get your weight further back than from the drops.

Andy_K 05-22-14 01:49 PM

Quote:

Originally Posted by rekon (Post 16782683)
Downhill = For a 10 mile stretch its about 400 ft downhill. The downhill is not constant and it's mixed with level and uphills.

The bike can definitely handle that. From there it's a matter of establishing your own comfort zone. I've taken my CX bike on some local fire roads that drop 500 feet in a mile. That's pushing my limits, but a lot of people see it as pretty ho-hum stuff.

Short steep drops are the thing that nearly make me pee myself. There's a local race that is notorious for one particular drop. Here's a pic of one rider showing great form:

http://farm8.staticflickr.com/7291/1...41c89f62_z.jpg

though if she isn't careful with the front brake, this could end badly.

I usually ride this section something like this (though this isn't me):

http://farm6.staticflickr.com/5492/1...eec842a6_z.jpg

The key, I think, is to keep your weight centered over your pedals, pushing vertically down into the pedals, not perpendicular to the trail surface. The steeper the hill, the more you need to shift your weight back. And when it gets really steep, resist the urge to brake hard.

rekon 05-22-14 02:50 PM

Quote:

Originally Posted by flargle (Post 16782780)
Hoods are the worst place because you don't have a solid grip. Bar-top interrupter levers are great for steep descents because you have a solid grip and can get your weight further back than from the drops.


Ok, maybe that's why I was on the hoods - I was riding out of the saddle. If I'm in the saddle the drops will be easier. Which leads me to wonder - doesn't it hurt to ride downhill in the saddle. Assuming the trail is very bump/rocky

shelbyfv 05-22-14 05:19 PM

You don't want to be on the saddle. Look at the pic. Her butt is way off the back of the saddle.

Barrettscv 05-22-14 05:27 PM

Most likely, it's a combination of speed, steepness and slope that creating the challenge on your route. Leaning back and slowing down will help. What tires and what size tire are you using?

rekon 05-22-14 10:02 PM

Quote:

Originally Posted by Barrettscv (Post 16783254)
Most likely, it's a combination of speed, steepness and slope that creating the challenge on your route. Leaning back and slowing down will help. What tires and what size tire are you using?

Thanks. I'll try that tomorrow.

My tires are stock: Kenda Kwick 700x30c

More specs of my bike here (Save Up to 60% Off Motobecane Cyclocross Bikes - Fantom Cross Outlaw)

Oh and here's my bike:

http://s4.postimg.org/r02ewgxh9/photo_20.jpg


Is the tire size/kind OK? What are your thoughts?

Barrettscv 05-23-14 05:56 AM

Quote:

Originally Posted by rekon (Post 16783833)
Thanks. I'll try that tomorrow.

My tires are stock: Kenda Kwick 700x30c



Is the tire size/kind OK? What are your thoughts?

That's a very small tire size for the type of riding you describe. Consider the Kendra Happy Medium in a 700x35 size: http://www.kendatire.com/en/bicycle/...py-medium-pro/

A larger tire provides better grip and improved stability on technical terrain. It also allows you to reduce air pressure to 40 to 50 psi, improving the shock absorbing capacity of the tire. That improves traction further while improving rider control and comfort.

I run a variety of tires on my CX bike, depending on the surface. I like slicks for pavement and smoother gravel that's not too technical. I use the Happy Medium on wet gravel and earth trails. I'm installing a 700x40 touring tires for some sharp-edged gravel that I'll travel next week.

Using a range of tires is the greatest benefit of having a CX bike. It transforms the performance of the bike completely.

rekon 05-23-14 08:08 AM

Quote:

Originally Posted by Barrettscv (Post 16784287)
That's a very small tire size for the type of riding you describe. Consider the Kendra Happy Medium in a 700x35 size: Happy Medium Pro

A larger tire provides better grip and improved stability on technical terrain. It also allows you to reduce air pressure to 40 to 50 psi, improving the shock absorbing capacity of the tire. That improves traction further while improving rider control and comfort.

I run a variety of tires on my CX bike, depending on the surface. I like slicks for pavement and smoother gravel that's not too technical. I use the Happy Medium on wet gravel and earth trails. I'm installing a 700x40 touring tires for some sharp-edged gravel that I'll travel next week.

Using a range of tires is the greatest benefit of having a CX bike. It transforms the performance of the bike completely.


thanks this helps a lot! So, will these tires fit on my current wheels? Or, will I have to buy new wheels?

Barrettscv 05-23-14 08:10 AM

Quote:

Originally Posted by rekon (Post 16784581)
thanks this helps a lot! So, will these tires fit on my current wheels? Or, will I have to buy new wheels?

These will fit on your current wheels, no problem. The Happy Medium is a great tire. It will be fast and smooth on pavement. It climbs as well or better than your current tire and provides great control going downhill. It's not the best tire for mud, but that's not an issue in So Cal.

flargle 05-23-14 08:39 AM

Watch this for sure:
Local trails ala cx on Vimeo

rekon 05-23-14 08:42 AM

Quote:

Originally Posted by Barrettscv (Post 16784590)
These will fit on your current wheels, no problem. The Happy Medium is a great tire. It will be fast and smooth on pavement. It climbs as well or better than your current tire and provides great control going downhill. It's not the best tire for mud, but that's not an issue in So Cal.

Perfect, thank you! I'll give these tires a whirl!

Correct, mud is not an issue - we are experiencing a drought out here. I don't remember the last time we had good rain! lol

rekon 05-23-14 08:44 AM

Quote:

Originally Posted by flargle (Post 16784688)
Watch this for sure:
Local trails ala cx on Vimeo

Nice! Here is a pic of my trail. I get more shots of the steep and rocky parts soon.

http://s27.postimg.org/exc5o8603/WP_20140521_004.jpg

fietsbob 05-23-14 09:07 AM

& with Top mount Interruptor levers , you may be able to push your center of gravity lower and further back..

Cross Boots had heel spikes to grip sketchy course downhills portaging the bike, until you got back to a ridable section of the course.


But the OP is just negotiating a unimproved dirt road , sorry if you have to slow down or risk crashing.. so it goes ..

walking is still an option ..

Barrettscv 05-23-14 09:14 AM

Quote:

Originally Posted by rekon (Post 16784699)
Nice! Here is a pic of my trail. I get more shots of the steep and rocky parts soon.

http://s27.postimg.org/exc5o8603/WP_20140521_004.jpg

That looks like a very nice commute!

It also looks like the biggest issue is off-camber and loose dry earth on the surface. A larger tire at lower air pressure combined with taller knobs on the shoulder of the tire are needed.

flargle 05-23-14 09:58 AM

Quote:

Originally Posted by rekon (Post 16784699)
Nice! Here is a pic of my trail. I get more shots of the steep and rocky parts soon.

Beauty place. Looks like fun.

rekon 05-23-14 10:23 AM

Quote:

Originally Posted by Barrettscv (Post 16784815)
That looks like a very nice commute!

It also looks like the biggest issue is off-camber and loose dry earth on the surface. A larger tire at lower air pressure combined with taller knobs on the shoulder of the tire are needed.

Thanks! So, with that said, is 700x35 tire size (http://www.kendatire.com/en/bicycle/...py-medium-pro) still sufficient?

Barrettscv 05-23-14 10:28 AM

Quote:

Originally Posted by rekon (Post 16785072)
Thanks! So, with that said, is 700x35 tire size (http://www.kendatire.com/en/bicycle/...py-medium-pro) still sufficient?

It is for combined pavement and trail use. If you are on that trail more than 75%, you might consider a full knobby. A full knobby tire is much slower on pavement. Considering that you had no problem climbing on the Kendra Kwick, you should be good on the 700x35 Happy Medium.

Clem von Jones 05-23-14 11:25 AM

Stay in the drops, hang your ass waaay out over the back and put you stomach on the saddle. Go slow enough that if you crash no damage is done. Be prepared to jump off from the back and catch your bike by its seatpost. Strongly disagree with the "lean back" advice, I mean you gotta move your position as far back as possible but you want to stay really low and stomach-down while keeping enough weight on the front wheel. Keeping enough weight on the front wheel is critical for downhill switchback turns. If you lean backward on a switchback the front tire will lose grip and slide. Go slowly and cautiously. Better to walk your bike down really loose stuff or unfamiliar territory if you tires aren't aggressive enough. I only use my interrupter levers going uphill. Can't even imagine being anywhere but in the drops during a steep descent even with significant bar drop.

jsigone 05-28-14 10:50 AM

lean back but stay balanced. Don't think about crashing or you will. Very fun looking trails. I have disc brakes on my rig and they really help. More control and ZERO chatter:thumb:

rekon 06-02-14 10:04 PM

Update: I've been doing a lot better on these downhills. However, my BB5 brakes feel a little sketchy. I'm thinking about upgrading to BB7s. Has anyone had experience doing this upgrade? If so, how do you like them?

Also, I'm planning on ordering the happy medium tires soon. Question - Do 700x35 fit on my bike? I'm assuming they do but just making sure...


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