Drafting and climbing on dirt vs. road

ccand51997 wrote: I was wondering two things; first, how effective do you find drafting on dirt and what sort of multiplier would you use to compare climbing on the road vs. gravel/dirt.  
I'm trying to figure out if I want to give the Cedar City BWR race a go but at 125 miles that is way beyond what I have attempted so far.  My gravel races have been smaller affairs, with six or seven thousand feet of climbing, so being attached to a group has not been vital so far. Then last week I was caught out solo with 15 miles of headwind to the finish.  

stu wrote:
Hitting something you don't see could be a bigger problem drafting on gravel than on pavement.

ccand51997 wrote: I was wondering two things; first, how effective do you find drafting on dirt  

bnystrom wrote:The others who responded are all correct, plus climbs on gravel are often steeper that you encounter on pavement, making gearing more critical and traction more of a concern. I typically don't draft quite as closely as I do on the road, whether uphill, flat or downhill, as I want to have a bit more time to react to unpredictable movements.

The biggest concern is actually descending, due to the often very high speeds (steeper up often means steeper down) and potentially loose/rough surfaces. In dry conditions, dust can reduce your vision, making it even more hazardous. I tend to descend quickly because I'm pretty comfortable doing it on loose surfaces. It can be a good place to make up time on other riders who aren't so confident.

Drafting on dirt and drafting on road give you the same benefits for a given speed. The difference is the rolling resistance on dirt is a lot higher and the speeds are a lot slower, so it feels like you aren't getting the same benefit when you actually are.

Depending on what "gravel" means to you, BWR might be doable or not. A 60 mile 6,000 foot mixed terrain route in my neighborhood would be equivalent to a 75-85 mile ride in Cedar City similar elevation solely because my trails are more technical so I have to go slower (assuming similar weather). I'm hardly ever going over 15 mph on dirt in my area, whereas we were doing segments in Cedar City at 22 mph. BWRCC's course is changing, but being attached to a group is definitely beneficial for most of the course.

Renegade wrote:

This is me to a T.  I haven't learned the fine art of descending on gravel yet.  No matter how many hills I go down, I am just not as confident.  Same with the roadie to some extent.

chas wrote:  It gets really hard to react to the road surface when drafting down a gravel road.  That, and in race conditions you often can't really pick your line.    

I do it, but not like on a road bike.  I leave more distance, and try to be off to the side a little so I can see in front of the bike in front of me.  

bearlyfinish wrote:

Depending on what "gravel" means to you, BWR might be doable or not. A 60 mile 6,000 foot mixed terrain route in my neighborhood would be equivalent to a 75-85 mile ride in Cedar City similar elevation solely because my trails are more technical so I have to go slower (assuming similar weather).
I've done another course in Cedar City for three years running that is 60 miles and 7,200 feet of climbing.  Because it does not have the brand name behind it, there are usually only about 80-120 riders and I usually ride everything but the first 10 miles solo.  
I get the sense that the BWRCC has a lot of better graded gravel down in the valley. 
I'm hardly ever going over 15 mph on dirt in my area, whereas we were doing segments in Cedar City at 22 mph. BWRCC's course is changing, but being attached to a group is definitely beneficial for most of the course.
That is kind of what I was wondering.  Especially with the way the wind blows there.  Even if you were only going 12 mph, a 10-20 mph headwind means your windspeed is 20-30 mph where drafting really matters.  

Agree on drafting on dirt — it works, but I’m not as comfortable being on a wheel and not being able to see what’s coming.  So I tend to hang back or offset a bit more than I would on pavement, which makes drafting less effective.

That’s especially true on downhills.  I don’t try to follow closely on dirt. Falling hurts too much at my age. ;-)   

Climbing, the biggest difference is traction.  On steep dirt I can’t stand the way I would on pavement.  Gearing that lets me climb the steepest stuff seated is a must.

At my normal climbing speeds on dirt, I think drafting is more psychology than physics.