Green chalk – Am I being too timid?

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  • Green chalk – Am I being too timid?
  • Premier Icon linusr
    Subscriber

    Having the front wheel slid sideways is never a good feeling. So when I encountered a stretch of green chalk this afternoon on the North Downs Way heading towards Canterbury I put both feet down and dismounted. Although I’ve been riding on tarmac since I was a kid this 58 year old is not the most exp MTB rider. I have a Maxxis DHF up front at 28 psi (80kg rider). Am I too timid, doing something wrong, or right to err on the side of caution?

    5plusn8
    Member

    Front wheel sliding normally means not enough weight on the front.
    I recommend a trip to Jedi, he’ll teach you to corner and how to trust your grip. https://ukbikeskills.co.uk

    Premier Icon howsyourdad1
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    Bones mend press send

    Gunz
    Member

    Absolutely not too timid, wet/green chalk is the work of the devil and I don’t believe any amount of training will give it magic grip. The last time I saw someone confidently speed across the stuff they ended up with a 6 inch flint gash down their calf, it wasn’t pretty.

    Onzadog
    Member

    What size tyre and what compound?

    I weight more than you and run about 10 psi less in the 2.5″ WT maxxterra while riding the peak district.

    As above, more weight on the front helps with traction, so does not braking – but sometimes, discretion is the better part of valour.

    shermer75
    Member

    Bones mend press send

    Lols!

    Green chalk is bloody lethal. I’d rather ride a CX bike down the rockiest descents in the Peak than take a DH bike down some of the South Downs bare chalk descents when they’re wet and green.

    Premier Icon nixie
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    28psi! That’s a lot. Last ride out I was on 18psi (2.4″ with a rimpact fitted), 76kg rider.

    Premier Icon davosaurusrex
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    For those of you that haven’t had the pleasure green chalk has the same amount of traction as ice. Some years ago I came across a stretch of it at the top of descent, too late to stop so had no choice but to let go of the brakes, keep the bike upright and relax. 3 seconds later I was upside down in a barbed wire fence off the side of the trail. So no, OP, not too timid.

    Premier Icon pictonroad
    Subscriber

    I’ve known of two snapped legs from green chalk.

    I’m firmly in the timid camp, happy to stay here too.

    Onzadog
    Member

    We have wet limestone up here. Also knows as soap stone for obvious reason. You actually get better traction when it has iced over.

    Nothing works on green chalk, I just tend to keep the speed up to transition the peril zone quicker.  Too many times I’ve heard people say it’s a bit slippery I slow down and then come too grief.  Michelin Wild Muds are the best I’ve found so far and I run then at 18psi (but that’s marginally grippier, not massively grippier).  Todays outing on a 2.6 Rekon up front and a minion ss on the rear was entertaining at best with both wheels spending a lot of time at angles vastly different from direction of travel/intended direction of travel.

    Premier Icon zippykona
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    The phrase I use is “riding today so I can ride tomorrow”.

    Premier Icon tenfoot
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    Lots of that round where I live too – Kent North Downs. There are some trails we stay off when it’s wet as even a slight off camber has you off the bike. Nasty stuff, it’s like someone just whips your front wheel out from under you.

    “We have wet limestone up here. Also knows as soap stone for obvious reason. You actually get better traction when it has iced over.”

    Yes but limestone has edges, so there’s some hope of your tyres finding some purchase before you hit the deck. Green chalk is totally smooth, it’s like trying to ride down a giant-sized, well-greased, teflon-coated baking tray.

    Premier Icon tenfoot
    Subscriber

    I recommend a trip to Jedi, he’ll teach you to corner and how to trust your grip.

    The slightest camber will have the wheel sliding. No need to be cornering.

    Premier Icon linusr
    Subscriber

    Thanks for the advice people. I”m no doubt running too much pressure up front. But green chalk in the wet and off camber is to be treated with extreme caution. I’m riding the route the reverse way on Sunday so I’ll be ready to dismount and walk it. Though even my grippy Five Tens were sliding today on it. I’ve already got titanium pins in my hip from a stack on wet tarmac 15 years ago. I’ll stay timid. Have a good weekend everyone.

    Premier Icon Poopscoop
    Subscriber

    Op, I’m 50 and I had a fairly slow speed fall on the South Downs (in the dry!) back in April. Front slid out on a tiny bloody ridge. Tiny!

    I’m still going to and doing physio to try and get decent use back of my right shoulder after the resultant torn rotator cuff.

    I’m not a good technical rider and it’s occurred to me that though I enjoy a little meshed “fear” on the downhils, the real thrill of biking to me is where it gets me too. Bloody love tinkering with bikes too.

    This recent incident has given me pause to think. I just don’t get over injuries fast now and the thought of not being able to bike again over a stupid bit of latent hubris within me is just too much.

    No shame in walking a stretch if doing so ensures you get to ride another day.

    Sure, you could still have a nasty crash whilst playing it safe but at least you won’t kick yourself later in A&E for riding something you knew was risky.

    No right or wrong to this though, make your own risk assessment and go from there I say.

    Enjoy the Downs mate!

    Premier Icon Poopscoop
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    P.s. I genuinely don’t think any the can be trusted on green chalk. No way would I attempt it unless I had no chance to stop before I saw it.😊

    submarined
    Member

    Nah, chalk is a bloody nightmare. Couple of years ago I remember a mate and I riding the old school DH at Friston. The bottom section criss crosses a chalky fire road a few times. Popped into the chute ok, came out of it,crossed the fired road to the bus stop with a slight slide but just caught it, Out of the bus stop slightly off camber aaaaaaaand the rear wheel just went. Furiously dabbed the inside foot repeatedly, just about kept it upright, but the marks showed about 20ft of furious scrabbling.
    I think I’d rather ride ice tbh. No technique or tyre will save you.

    Premier Icon oldnpastit
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    Friend headbutted the ground after coming off on wet chalk on the SDW. Not good.

    Premier Icon linusr
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    @poopscoop my thoughts exactly. Getting out for some exercise in the countryside is what I enjoy. I rode the SDW last year over several days and enjoyed every minute of it. NDW is a bit more complicated – and longer. Both great riding.

    Premier Icon jimdubleyou
    Subscriber

    I still have a scar on my leg from a green chalk slide and subsequent filnt/skin meet up.

    Nasty stuff…

    corroded
    Member

    You’re not being timid! There are stretches of green chalk on some descents in my part of the SDNP that are impossible to walk down let alone ride. Usually on the little-used BWs and under cover.

    Premier Icon BadlyWiredDog
    Subscriber

    There are two conflated issues here, no?

    1. Q: Is it okay to get off and walk stuff you’re not sure about generally? A: Yes, of course it bloody is. You’re the best judge of where you feel happy regardless of what anyone else says (particularly on the internet, where everyone is a super hard technical riding god).

    2. Q: Is wet, green chalk very slippery? A: Too right, the stuff is like ice. Approach with extreme caution (see above)

    Also:

    3. Q: Will a Minion DHF at 28psi somehow negate the effect of wet, green chalk as above? A: Absolutely, in the same way that crossing your fingers will stop a bullet from penetrating your skull.

    4. Q: If I were more ‘experienced’ would wet, green chalk somehow be okay? A: No.

    So, OP, you were completely rational and reasonable in your behaviour. I put wet chalk in the same category as Chiltern winter mud and celery, ie: something that you won’t quite believe how bad it is until you experience it for yourself. Come and ride in the Peak where we don’t have that stuff 🙂

    Rockhopper
    Member

    No idea on the green chalk but I’m 20kg heavier than you and run 20psi on both ends of my bike so i think dropping your pressures a fair bit would give you more feeling of what the tyres are doing and hence have more confidence in them.

    dovebiker
    Member

    One of my abiding green chalk memories was attempting to ride the track down from the NDW to Shere Bottom after a wet spell – I used the same technique when encountering icy gullies in the far north – feet off pedals, sat on top tube and using my feet as stabilisers and just doing a ‘controlled’ slide

    mariner
    Member

    No.
    Descent of Harting Down ended my SDW ride.
    The chalk was so slippery it was almost impossible to walk the rest of the way down.

    Premier Icon Ambrose
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    ‘I still have a scar on my leg from a green chalk slide and subsequent filnt/skin meet up.

    Nasty stuff…’

    Me too, I still have the scars (and the Ron Hill’s I was wearing at the time).

    TiRed
    Member

    Walk. If you value your collarbones.

    I have been on the south downs a fair amount and in my opinion, green chalk is vindictive and its only mission is to have you off your bike; It can’t be reasoned with, it can’t be bargained with…it doesn’t feel pity of remorse or fear…and it absolutely will not stop.Ever. Until you are dead.

    Premier Icon zippykona
    Subscriber

    Has anyone ever tried ice spike tyres on it?

    The Friston Irregulars I ride with always joke that at least one World Cup DH course ought to have a shady, fast, rooty, off camber corner made from Sussex chalk sprayed with water for at least a week before the race, with a large grassy runoff area and lots of cameras.

    Premier Icon northernsoul
    Subscriber

    Green chalk is totally smooth, it’s like trying to ride down a giant-sized, well-greased, teflon-coated baking tray.

    Has anyone got any pics (Google image search on this being slightly tricky)? It’s not something I come across where I usually ride. The worst thing I’ve experienced recently that might be comparable is frozen rain (last year) – with the added bonus that it can appear anywhere, inc. places usually rideable.

    Premier Icon winston
    Subscriber

    Plenty of it about at the moment. One climb I have a top 5 in Strava using my gravel bike…..couldn’t even get up it today on my fat bike – back wheel kept spinning out and that has a Dillenger 5 on!

    I just looked at the stats for todays 15 mile ride and it looks like I was riding with my gran – so no OP you are not being timid..or we both are but I’m with Zippykona on this. Ride like this today so I can ride like I stole it another day.

    fossy
    Member

    I’m Peaks/Wales, so never seen chalk… only been MTB only last 3 years though… magic slippy muddy stuff with added ‘Slick 50’ I expect….

    “Has anyone got any pics (Google image search on this being slightly tricky)? It’s not something I come across where I usually ride.”

    When chalk is bone dry it’s pretty nice stuff to ride on – you get some slippery dust on top but it’s fine (until it starts to break up and then you get chalk marbles).

    When it’s wet but still white you get this thin chalky paste which is very slippery indeed but in a vaguely manageable way, like you can stick a foot out and catch yourself or tripod down something steep with a modicum of control.

    When chalk stays wet for a while, with little traffic or sunlight, you get this weird algae-like growth on it. If you haven’t encountered the chalk hills in winter then you might have had the fun of trying to wade across a rocky river in the Lakes or Cairngorms or somewhere else wild – you know that moment when you step on a green-tinged rock and there is ABSOLUTELY NO GRIP and you know that you’re almost certainly going to get very wet short of a minor miracle?

    It’s that kind of stuff – but instead of being on a rock underwater it’s like someone has seen a bare chalk path which is already pretty short of grip in the wet and sprayed a huge swathe of this green gelatinous grease across the whole damned route for dozens of yards.

    When you’re on this stuff you are only going to travel the way gravity and your momentum conspire to send you – you cannot apply any force through the ground to control your direction or attitude, unless you’re wearing running spikes or crampons.

    mariner
    Member

    Even in good weather it plays rough.
    On my SDW ride a sea mist rolled in and just coated the surface of the chalk with a thin film of moisture. Blue skies overhead but for me it was straight to the scene of the accident.
    That must have been two or three years ago and my front dry bag still has a chalk smear on it.

    Premier Icon Poopscoop
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    linusr

    Subscriber
    poopscoop my thoughts exactly. Getting out for some exercise in the countryside is what I enjoy. I rode the SDW last year over several days and enjoyed every minute of it. NDW is a bit more complicated – and longer. Both great riding.

    @linusr
    Hah! Multi day SDW ride oh yeah. Done that, as detailed in the multi year SDW thread.
    Not sure to ride it again next year or try Peddars Way or Ridge Way…. Trouble is, the scenery on the SDW is incredible. Might just ride it in reverse. Over 2 or 3 days again.

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