Mountain Bike Reviews Forum banner
Cancel
Create thread New Forums

High Speed Gravel Descent Safety

Jump to Latest

Safe maximum speed of these tires on this gravel road

  • 30 mph

    Votes: 1 7.7%

  • 35 mph

    Votes: 3 23%

  • 40 mph

    Votes: 0 0%

  • 45 mph

    Votes: 0 0%

  • 50 mph

    Votes: 2 15%

  • Something else will fail before the tires

    Votes: 7 54%
  • Total voters
    13
1 - 20 of 21 Posts
A

akmtnrunner

· Registered
Joined
·
123 Posts
Discussion starter · #1 ·
I've been riding a long gravel road climb up and down for conditioning while my local trails dry out. Descent speeds easily top 30mph and I am sure I could approach 40 if I pushed it. I've never really pushed XC tires very hard but I certainly don't want to have a failure at this high of speed. I am on Vittoria Barzo/Mezcal TNT Trail casing 2.25" on 29 ID rims at 20-22 psi. No inserts but I can say there's very little risk of rim strikes.

Most of the loose gravel on top is rounded but there is the occasional broken piece with a sharper edge. I am pretty good at spotting and avoiding those. Anyone willing to estimate a safe working maximum speed on these tires on a gravel road like this?
 
#3 ·
What exactly are you worried about? Loss of traction on tight corners? That is a real concern but you just need to know your limits. Tire blowing off the rim due to speed? Not sure I have heard that happening even with lower pressure tubeless tires. I routinely hit 45+ mph with no issues even on tighter paved corners. Same paved roads riders can easily hit 55 mph+.
 
#9 · (Edited)
I agree with everyone else. The corners are the issue and they can get really sketchy. You have to trust your equipment, have faith in your skill, and know your limits. I find the pebbles over a hard surface to be the most sketchy surface so watch out for those. They can shift or roll while you're traveling over them.
 
Discussion starter · #12 ·
Thanks for the thoughts, everyone. You're putting my concern for something out of my control at ease. It's easy for me to feel the squirm and loss of traction thresholds so I'll let off the breaks more where those aren't an issue.
 
#13 ·
Lol, your mind should most definitely not be at ease. If you're trying to hit 50 on gravel, you're running a pretty high risk for pretty low reward ratio. Even on relatively knobby gravel tires, the loose spots catch me off guard.
 
#14 ·
akmtnrunner said:
Thanks for the thoughts, everyone. You're putting my concern for something out of my control at ease. It's easy for me to feel the squirm and loss of traction thresholds so I'll let off the breaks more where those aren't an issue.
Click to expand...
The worst injury I've ever seen riding is a skull fracture on a gravel descent. His tires were fine, but he went too hard and lost control. It only takes a fraction of a second.
 
Discussion starter · #15 ·
I guess I should clarify that I am not trying to push the speed. Just trying to assess the likelihood of a tire failure due directly to high speed over gravel. Rest assured, I am not threatening any strava times and my goal is the conditioning from climbing the road then getting safely down it.
 
#16 ·
akmtnrunner said:
I guess I should clarify that I am not trying to push the speed. Just trying to assess the likelihood of a tire failure due directly to high speed over gravel. Rest assured, I am not threatening any strava times and my goal is the conditioning from climbing the road then getting safely down it.
Click to expand...


Have you ever watched the pro's racing Unbound Gravel or BWR? They are using way skinnier and lighter tires than you are and frequently are traveling at sketchy speeds. They do puncture now and then but catastrophic failures are pretty much non-existent as far as I'm aware.

I would be careful of course, as mentioned going down on gravel at any speed can be pretty bad, one of my more painful falls ever was going uphill on gravel at about 15mph.
 
#18 ·
J.B. Weld said:
Have you ever watched the pro's racing Unbound Gravel or BWR? They are using way skinnier and lighter tires than you are and frequently are traveling at sketchy speeds. They do puncture now and then but catastrophic failures are pretty much non-existent as far as I'm aware.

I would be careful of course, as mentioned going down on gravel at any speed can be pretty bad, one of my more painful falls ever was going uphill on gravel at about 15mph.
Click to expand...
JB is correct. Unbound is a gravel race where they average 20 mph for 200 miles and the winner this year hit a top speed of 41 mph.

Power analysis: Ian Boswell's epic race-winning ride at Unbound Gravel - CyclingTips
 
#20 ·
RSAmerica said:
Respect the gravel, I had a big crash in Pisgah on Yellow Gap road went down at 27 mph. Broke 6 ribs, scapula, collarbone, collapsed lung plus had to walk out 5 miles which took 2.5 hours. Ended up in the hospital for a week.
Click to expand...
Speed is a mutha!
I suffered a front tire blowout on a road bike doing downhill at 35mph once -- I never imagined my body would slide on pavement so long.
The ER treated me like a burn victim after they dug a bunch of gravel out of my hamburger.
That day I learned just what a thin layer comprises human skin. Underneath that oh so thin layer -- human steak.
Most unpleasant experience. Missed two weeks of work. I do not recommend.
As bad as it was, I can only imagine how much worse it would have been if I'd done the same thing on gravel.
=sParty
 
1 - 20 of 21 Posts
About this Discussion
20 Replies
13 Participants
Last post:
jrob300
Mountain Bike Reviews Forum
posts
16M
members
534K
Since
1990
A forum community dedicated to Mountain Bike owners and enthusiasts. Come join the discussion about bike parts, components, deals, performance, modifications, classifieds, trails, troubleshooting, maintenance, and more!
Full Forum Listing
Explore Our Forums
General Discussion Downhill - Freeride California - Norcal Shocks and Suspension Passion