Viewing 17 posts - 1 through 17 (of 17 total)
  • Twitchy oversteer from modern offset?
  • Premier Icon TrailriderJim
    Full Member

    I often find the front wheel turning in too easily on tight corners, to the point where the front can dive from under me. I’m on a 2018 Whyte 909 with 35mm stem and (if I recall) a 44mm offset Fox 34. Is it just me and pilot error or does modern offset and short stem contribute?

    Premier Icon damascus
    Free Member

    How wide are your bars?

    Premier Icon TrailriderJim
    Full Member

    760mm. Renthal Fatbar Lite.

    Premier Icon poah
    Free Member

    sounds more like technique issues.

    Premier Icon binman
    Full Member

    I think the Rockshox forks on that 900 series has even less offset (42mm ?), so might be worth playing with bar height / stem length ?

    Premier Icon chestrockwell
    Full Member

    I found going to a 35mm stem ruined the handling for me. Seemed that it was very twitchy and the steering would go from not happening to all happening at once. Switched back to 50mm and the problem went away.

    For reference, 800mm bars, 150mm 29″ forks with 51mm offset.

    Premier Icon ampthill
    Full Member

    My understanding is that you need more self centering. A longer stem should help. But i’m in no way an expert

    Premier Icon mrdestructo
    Full Member

    My Marin SQ3 has a 65deg HA and 37mm offset and when I set off on a ride on it I have to take time to get used to it as I’m all over the place, can’t keep a straight line. I removed the oem short stem and put a 60m 7deg stem and seriously high riser bars (780*91mm) because the front end was too low (XL frame, 6’3″) No noticeable change to twitchiness changing the stem/bars).

    It does have positive qualities, bouncing over obstacles and when pointed downhill. But I feel theres a couple of things it can’t do. (Straight lines at low speeds and endos).

    Premier Icon thols2
    Free Member

    put a 60m 7deg stem

    Premier Icon mrdestructo
    Full Member

    That hurts so much more, given the field of work I’m in 🤣

    “mm” of course. A

    Premier Icon tall_martin
    Full Member

    Longer stem or different tyres?

    My old hardtail rode much better with 100mm stem. 50mm was the cry of the magazine’s so I tried that.

    It became a twitchy, wandery mess.

    What was your bike designed around? If it wasn’t designed for 35mm I’d try whatever it was designed for I’d go for that. If it was designed around 35, I’d go for 50mm.

    I had conti race kings-2.2 very low tread  tyres on another bike. They made the front end of that bike tuck unexpectedly at speed. A change of front tyre sorted that.

    Premier Icon epicyclo
    Full Member

    Too much flop is the price of slack head angles. There are compensatory measures, e.g. big wide bars. Steering dampers help too.

    Cycling went through a slack HA phase in the 1920s and early 1930s resulting in horrible handling atrocities.

    Premier Icon greyspoke
    Free Member

    Slacker head angle = more flop (until you slacken to 45 degrees). More trail gives more flop as well, but at higher speeds trail is good, and choices of fork offset are limited.

    Another factor is tyres. Fat tyres at low pressures tend to tuck in and like @tall_martin indicated tyre construcoti0n and shape can affect the extent of that.

    Premier Icon mrdestructo
    Full Member

    How are people riding skinny’s nowadays with modern, slack bikes, with low tyre pressure, at slow speed? The footage off my camera is disconcerting. Makes me look like I’ve had a liquid lunch!

    I was servicing my bike tonight and read the stem markings. Mine is 80mm, not 60!!! I realised, although 4bolt, it is unbranded, so ordered a Dabomb Shark 80mm stem for some “perceived” protection. I’ve recently met some local riders who’ve been digging in a “gentle” DH course in the mountains next to my city so don’t want a failure there.

    Premier Icon chakaping
    Full Member

    OP – I used to get the same tucking feeling in tight corners with 51mm offset forks, and cured it with 42mm and 44mm forks on two of my bikes.

    So it might not be the fork offset that’s the culprit.

    How are people riding skinny’s nowadays

    They aren’t.

    Premier Icon continuity
    Free Member

    Had that on a 35mm stem on my following. Hated it. 50 fixed it.

    Premier Icon walleater
    Free Member

    I don’t think it’s one thing.
    My Norco Sight 29 tucked into tight switchback corners which was a little un-nerving for a bit.
    On the other hand it was great at higher speed / more mellow corners as it would hold a line really well.
    My Norco Shore (27.5) has a slacker head angle but does not tuck into tight corners at all. For a bike with a 63 degree head angle, the steering is pretty quick when needed, but predicable throughout the steering axis.
    Both bikes had / have the same length stem and bar length IIRC. 40mm / 790mm.
    I also had a custom built hardtail a while back with for it’s time a pretty slack head angle. With the first fork that I installed (OG Revelation) the steering had the dreaded flop at slow speeds. The fork wasn’t great anyway so put on a Suntour Auron fork which had the same length and travel. The flop completely went away. So offset must have something to do with it.

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