Results 1 to 13 of 13
  1. #1
    mtbr member
    Reputation:
    Join Date
    Sep 2017
    Posts
    100

    Maximum Tire Grip on Berms

    I've recently been riding good berms more and trying to master the craft... I've been contemplating tire choice, profile and pressure for maximum grip. For discussion, let's assume a good, 4', 35-45deg berm in good condition, not loose and blown out. Obviously such a berms provide great traction regardless of tire setup, but everything has its limit. I worry about front washing out...I suppose I've only washed out on loose and blown out berms, such (painful) occurrences are heard to forget.

    Specifically, I've been thinking about the Minions I like to run, and more recently the Magic Mary too, in that I'm not even sure I'm even making much use of the cornering knobs, as I don't think the bike is at much of an angle relative to the berm, although the Gs might be flattening the tire out a fair amount and helping in that regard. Wondering if running a tire/size with a bit more square profile is better for berm work so the edge knobs grab at less of a lean angle. Or maybe tires with less of a dead zone and some transation knobs are best?

    Thanks!

  2. #2
    mtbr member
    Reputation:
    Join Date
    Mar 2012
    Posts
    351
    Transition knobs take away from cornering grip. That gap in the tread allows the cornering knobs to really bite into the dirt.

    A flatter profile wont be of much help. If the contact patch is at the center of the tire then thats what tread will be gripping. To engauge a cornering knob like this you'd need a totally square profile which would be useless.

    For me berms on a mountain bike were tricky since I transitioned from motocross. Without having a throttle to save you on corner exit it makes corner entry more critical on a mountain bike.

    -Set your speed before the corner and take into consideration you'll be faster through the exit if its downhill. If you're at 100% for corner entry and pick up speed by corner exit you'll be screwed.
    -Keep your torso low with elbows up, butt kinda high with a slight bend at the knees. Weight centered mostly over the pedals.
    -Don't be afraid to load the front tire into the dirt digging in the knobbies.
    -Keep a relaxed grip. The geo of our bikes will let the front tire find traction on its own, if you're tense then you prevent it from doing that.
    -Don't lean the bike under you so much as you would in a flat corner. Watch a UCI World Cup rider hit berms, they stay pretty centered over the bike. You want to push into the berm which you can't do as well with the bike leaned under you.

    Some other points is you may need a little more pressure in your suspension. You're suspension should be around 70% compressed fully loaded into a berm. If its deeper in the stroke the progressive rate of suspension we have gets to harsh. Which could lead to a loss of grip on anything that isn't billiard table smooth. Obviously if you're faster there will be more load on your suspension which needs a different setup. Last thing is nothing beats new tires. As soon as that sharp edge is taken off a new tire cornering traction is drastically reduced. Don't expect a tire to corner the same at mile 20 and beyond as it did when brand new.

  3. #3
    Elitest thrill junkie
    Reputation: Jayem's Avatar
    Join Date
    Jul 2005
    Posts
    28,685
    Quote Originally Posted by RAG2 View Post
    I've recently been riding good berms more and trying to master the craft... I've been contemplating tire choice, profile and pressure for maximum grip. For discussion, let's assume a good, 4', 35-45deg berm in good condition, not loose and blown out. Obviously such a berms provide great traction regardless of tire setup, but everything has its limit. I worry about front washing out...I suppose I've only washed out on loose and blown out berms, such (painful) occurrences are heard to forget.

    Specifically, I've been thinking about the Minions I like to run, and more recently the Magic Mary too, in that I'm not even sure I'm even making much use of the cornering knobs, as I don't think the bike is at much of an angle relative to the berm, although the Gs might be flattening the tire out a fair amount and helping in that regard. Wondering if running a tire/size with a bit more square profile is better for berm work so the edge knobs grab at less of a lean angle. Or maybe tires with less of a dead zone and some transation knobs are best?

    Thanks!
    I tried to run a minion 2.3 DHF on my i30/od35 setup a few weeks ago.

    I couldn't roll the tire on to edge and turn, it was strange but it was like there was a knife-edge preventing me from rolling it and it would "stick" and not edge when I tried to change direction. It was real skinny obviously, since maxxis runs skinny, but I took it off, put it on the back, put an old 2.35 veredstien bulldog (really about a 2.4-2.5) on the front that was a bit worn, and I was back to nailing corners and pulling far more Gs with easy transitions and more traction. That minion on the front just didn't work. I've always had good success with minions, but not this time. My last ones were 2.5 29ers on my old enduro bike and they worked great.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

    You're turning black metallic.

  4. #4
    mtbr member
    Reputation:
    Join Date
    Sep 2017
    Posts
    100
    Thank you for the tips! Sounds like I might already have ideal tires for the situation...and Lucky for me, I just stocked on on brand new tires to play with, including an Aggressor 2.3, DHRII 2.4 (DC) and Schwable Rock Razor (Addix Soft) for the rear, and for the front I have a DHF 2.5 (3C), Magic Mary 2.35 and DHR 2.4 (3C). I suppose any combination of these should do the trick...

    Quote Originally Posted by Fajita Dave View Post
    Transition knobs take away from cornering grip. That gap in the tread allows the cornering knobs to really bite into the dirt.

    A flatter profile wont be of much help. If the contact patch is at the center of the tire then thats what tread will be gripping. To engauge a cornering knob like this you'd need a totally square profile which would be useless.

    For me berms on a mountain bike were tricky since I transitioned from motocross. Without having a throttle to save you on corner exit it makes corner entry more critical on a mountain bike.

    -Set your speed before the corner and take into consideration you'll be faster through the exit if its downhill. If you're at 100% for corner entry and pick up speed by corner exit you'll be screwed.
    -Keep your torso low with elbows up, butt kinda high with a slight bend at the knees. Weight centered mostly over the pedals.
    -Don't be afraid to load the front tire into the dirt digging in the knobbies.
    -Keep a relaxed grip. The geo of our bikes will let the front tire find traction on its own, if you're tense then you prevent it from doing that.
    -Don't lean the bike under you so much as you would in a flat corner. Watch a UCI World Cup rider hit berms, they stay pretty centered over the bike. You want to push into the berm which you can't do as well with the bike leaned under you.

    Some other points is you may need a little more pressure in your suspension. You're suspension should be around 70% compressed fully loaded into a berm. If its deeper in the stroke the progressive rate of suspension we have gets to harsh. Which could lead to a loss of grip on anything that isn't billiard table smooth. Obviously if you're faster there will be more load on your suspension which needs a different setup. Last thing is nothing beats new tires. As soon as that sharp edge is taken off a new tire cornering traction is drastically reduced. Don't expect a tire to corner the same at mile 20 and beyond as it did when brand new.

  5. #5
    mtbr member
    Reputation: WHALENARD's Avatar
    Join Date
    Feb 2010
    Posts
    2,708
    One of the best "flow trail" tires I've ever run is the vittoria morsa. Minions, especially dhf on front, is slippery (for lack of a better descriptor) in comparison, though they grap better in mixed trail conditions.
    It is no measure of health to be well adjusted to a profoundly sick society.

  6. #6
    mtbr member
    Reputation:
    Join Date
    Sep 2017
    Posts
    100
    Interesting. That is sort of what I was wondering about. Why do you think the Morsa does better here..closer spaced corner knobs? I'm in Idaho for the next month and have been hitting flow/berm trails...perfect condition as it just thawed out a few days ago and everything is pretty much tacky/hardback on the berms, though lots of lose pine needles on the "trails"...completely different than the loose SoCal conditions I just left (where the Minions rule).

    Quote Originally Posted by WHALENARD View Post
    One of the best "flow trail" tires I've ever run is the vittoria morsa. Minions, especially dhf on front, is slippery (for lack of a better descriptor) in comparison, though they grap better in mixed trail conditions.

  7. #7
    mtbr member
    Reputation:
    Join Date
    May 2018
    Posts
    12
    If you're concerned about going down in berms with the front washing out, here's some of the things I do:

    Lean the bike and not your body, this forces weight down and not out in the direction of a potential washout.

    I drag the front brake slightly, this loads up the front suspension and places more downward force on the front tyre giving extra grip this is especially useful on fast downhill corners.

  8. #8
    mtbr member
    Reputation:
    Join Date
    Mar 2012
    Posts
    351
    Quote Originally Posted by Desert City MTB View Post
    If you're concerned about going down in berms with the front washing out, here's some of the things I do:

    Lean the bike and not your body, this forces weight down and not out in the direction of a potential washout.

    I drag the front brake slightly, this loads up the front suspension and places more downward force on the front tyre giving extra grip this is especially useful on fast downhill corners.
    Braking requires traction. Traction that could be used for cornering instead.

  9. #9
    mtbr member
    Reputation:
    Join Date
    May 2018
    Posts
    12
    Quote Originally Posted by Fajita Dave View Post
    Braking requires traction. Traction that could be used for cornering instead.
    Dragging the front brake increases traction, could be the difference between going down in a corner or successfully coming out the other side.


    Sent from my iPad using Tapatalk

  10. #10
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    2,957
    Pardon me for being old and from WI, but after making and maintaining a pump track and leadership/management for miles of flow trail......

    Tires didn't make so much difference when I figured out berms are also rollers turned sideways, and same wisdom for all riding - look ahead. I ride same stuff with a quite round low tread DJ bike, AM/Enduro/Trail rig, basic hard tail 29r, fat bike, and Fargo. To me it's mostly about when you pump and when you don't. If it's a berm get your bike 90 degrees from the trail tread and not working the tire edge.

    We have 160 kids in lessons at the ski area. They come from different demographics and are on very different levels of gear. It totally shows that your technique is more important than what tire.

    To me keeping loose but in control just like carving, launching and landing skis is part of getting berms right. I get this personally because I can have very different tires, wheels and inflation with the bikes I described but it works when the technique feels right.
    ƃuoɹʍ llɐ ʇno əɯɐɔ ʇɐɥʇ

  11. #11
    mtbr member
    Reputation:
    Join Date
    Jun 2006
    Posts
    6,481
    Quote Originally Posted by bitflogger View Post
    Pardon me for being old and from WI, but after making and maintaining a pump track and leadership/management for miles of flow trail......

    Tires didn't make so much difference when I figured out berms are also rollers turned sideways, and same wisdom for all riding - look ahead. I ride same stuff with a quite round low tread DJ bike, AM/Enduro/Trail rig, basic hard tail 29r, fat bike, and Fargo. To me it's mostly about when you pump and when you don't. If it's a berm get your bike 90 degrees from the trail tread and not working the tire edge.

    We have 160 kids in lessons at the ski area. They come from different demographics and are on very different levels of gear. It totally shows that your technique is more important than what tire.

    To me keeping loose but in control just like carving, launching and landing skis is part of getting berms right. I get this personally because I can have very different tires, wheels and inflation with the bikes I described but it works when the technique feels right.
    Also a pumptrack builder/keeper and have ridden a lot of very slippery indoor skatepark terrain with my son, as well as spent time on BMX tracks etc etc...if you're riding a well built berm correctly, tread makes no difference whatsoever. That's pretty much the whole purpose of a berm in the first place, to allow you to tear around a corner without worrying about traction.

    If you're washing out, you're most likely riding them way too low, and/or the berm isn't built well. Forget shopping and practice, practice, practice.

    Also, typically the 'flowiest' riders I see at the track not only have little wheels with zero tread on them, many also run no brakes at all.
    Sinister Bikes
    Wraith Bicycles
    Sunday River Mtn Bike Park
    NEMBA
    Wachusett Brewing Co.

  12. #12
    mtbr member
    Reputation:
    Join Date
    Mar 2012
    Posts
    351
    Quote Originally Posted by Desert City MTB View Post
    Dragging the front brake increases traction, could be the difference between going down in a corner or successfully coming out the other side.


    Sent from my iPad using Tapatalk
    Your tires only have so much grip. If you're using grip for braking then its taking away grip that could otherwise be used for cornering. Especially when you're asking a tire to do two different things at the same time. It reduces not only grip to do either one or the other but also how predictable it will be in a slide. You can't have both.

    I'm with bitflogger that technique is by far most important. Especially to feel where the limits of traction are if you're actually pushing that far. If a tire does start to slide proper technique and being relaxed will greating increase your chances to save it. Even if you don't save it you'll at least have the presence of mind to feel what went wrong. Most people dive in way above their heads with a death grip on the bars and have no idea what went wrong when they take a dirt nap.

    I missed the part that you have super smooth hardpack trails. A tire with intermediate knobs can help there. A tire like the DHF can feel kind of squirmy on hard pack because the edges of the cornering knobs don't have any support. That channel and cornering lugs are great for clearing looser dirt and letting the cornering knobs dig in. If they can't dig in you're better off having more tread on the ground. In a 45 degree berm you probably probably wont be to far off the center of the tread.

  13. #13
    mtbr member
    Reputation:
    Join Date
    Jun 2006
    Posts
    6,481
    Just learn to ride the berm correctly and trust it to do it's job.
    If you're sliding out, you're taking it way too low and may as well be doing a flat turn.

    Once you get it right, a berm could pretty much be made of ice and you'd till be able to rail around it.
    Sinister Bikes
    Wraith Bicycles
    Sunday River Mtn Bike Park
    NEMBA
    Wachusett Brewing Co.

Similar Threads

  1. Replies: 19
    Last Post: 03-20-2018, 06:26 AM
  2. Light weight tires for xc/light trail with maximum grip?
    By Hollis Prince in forum Wheels and Tires
    Replies: 14
    Last Post: 11-19-2017, 10:21 AM
  3. Replies: 6
    Last Post: 02-12-2014, 02:56 PM
  4. Replies: 4
    Last Post: 09-20-2012, 10:54 AM
  5. best grip platform pedal to use with power grip straps.
    By package81 in forum General Discussion
    Replies: 7
    Last Post: 09-11-2011, 10:58 AM

Members who have read this thread: 95

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT MTBR

VISIT US AT

mtbr.com and the ConsumerReview Network are business units of Invenda Corporation

(C) Copyright 1996-2018. All Rights Reserved.