Frame fork Flex – Not for me.

Am I numb to bike set-up and function.

Reading the Commencal thread, they’re suppoosed flexy, I know the Float R 140’s are supposed to be flexy too. however, I never feel it, never notice it, can’t say I ever have, is it all hype, or have I ridden flexy bikes so long, that I don’t know what it’s like to ride a stiff bike?

Do mean flexy? Rather than resilient? Or springy? Or agile?

It’s a real phenomenon, but it doesn’t stop a huge amount of bollox being spoken about it: ‘I liked the ride but I wasn’t happy with the lateral stiffness of the rear end.’ etc. etc. It’s not a big deal, or even a detectable issue, on your average XC ride.

You notice flex the most when you’re riding the bike at speed, usually downhill. It will become more noticeable if you ride a lot of different bikes and compare the differences. I ride Cannondale bikes, with the ultra-stiff lefty fork. I can feel a bit of flex in normal forks by comparison under hard braking or cornering at speed. The other bike area people commonly talk about flexing is the rear end on a full sus.

I flex the cheap wheels on my CX bike, but I’ve not noticed ever having flexy wheels on a MTB.

I’m refering to the flex that people seem to think is a bad thing in a ride. I have a Commy Meta5.5, and although people complain about the flexy back end, I never notice any unwanted movement, same with qr fox forx, the 140’s are supposed to be way too flexy, the 130’s were just fine, acording to MBR.

I think what I’m trying to say, in my own way, is.

Is most of it just balls?? Do only better riders notice this flex in certain components?

I could however feel the springyness in the back of my 456, which was one of the things I liked about it the most.

From a technical stand point –

Flexy front end (this is all subjective as ALL modern forks are stiff in comparison to older models) will cause instabilty under braking

Whereas a rear end that flexes like on older 46’s and the like. This causes the front end to wander in the middle of corners.

So for most people to have the stiffer rear end improves the ‘handling’ of the bikes by having improved control from the mid point of the corner onwards.

To improve corner entry, having a correct length fork for you frame geometry, will be far more effective than than a ‘stiffer’ fork

Depends where you ride as to how much you notice the felx or appreicate the stiffness.

Here in the Lakes the difference between a 32 fork with standard QR and a pair of 36’s with a bolt through is massive.

On the tandem we could bend the Dirt jumper fork about 1 1/2 inches back towards the bike under braking. It was funny watching the front wheel bend back towards me. Not so bad with the Z1 although you can still see it. Try holding the brake on and push your bike forwards – its amazing how much they bend.

Flex is a part of the feel – and different folks prefer different feel. In motorcycle racing the tendency recently has been to introduce controlled flex into frames – as suspension does not work when leaned right over so frame flex has to absorb the bumps.

I’m not arguing whether the frames or forks actually flex, I’m just wondering out loud, does it really matter?

Tandem is a different kettle of fish I suppose

I’ve got a marzocchi shiver sc (from about 2002/3)

read the reviews – people **** on about how the wheel can be twisted in the fork (stand with wheel between knees & turn bars)

now I AM a kack rider, but I’ve never ever felt that steering was vague, or that the bike wanders under braking

It’s a really good fork, though a little bit heavy maybe

I find my noodly bomber Z1s a problem, they squirm about a bit and bend backwards under braking but then so does the tyre. The rear of my NRS is very flexy, doesnt cause me any problems unless I’m running a big tyre, then the tyre catches with each thrash on the pedals – that IS annoying. But affecting the way it rides – no, i dont think I notice. You notice extra vibrations on a rigid thick-walled alu frame more than on a thin walled or steel frame, but I’d say it was mostly rubbish, or I’m just not good enough to notice.

I could notice stiffness difference on the back end of frames when going from Scott G-zero 02 or 03 model to my Trek Fuel Ex5 2007 (and I read some reviews that that wasnt the stiffest frame on the market anyway). Can hear brakes rubbing on rim on my road/cx/commuter (3in1) dont know if its the Crosslight frame or Ksyrium Equipe wheels. Now Im back to HT and Maxlight is just spot on. Apart from the play on the bushings on my xc500 all the forks I had were flexing a bit but thats because Im pretty heavy. I think my current Reba is the stiffest one yet.

To be honest I cant really be bothered. Im only doing road or xc, both wheels on the ground, no jumps. When I read in MBUK about CrossRides and the straight pull spokes unhooking from collars when cornering really hard I started to wonder how hard do You have to corner as I never had that problem using them in XC with my 16st on the bike. My current Bonty race light wheels are just working and cant feel the stiffness difference between my old Mavics.

Actually, now I remember, I “detected” (half an inch or so each way by the time I got to a shop!) play in the swingarm bearings of my Bullit when they wore out once – was the understeer followed by oversteer at a random point round a corner (and back again) that gave it away I think 😯

(maybe I am a riding god ?)

I really noticed it going from a 32mm QR fork to a 36mm 20mm bolt through fork when nailing it DH over roots and rock gardens. The only other time ive really noticed it was on a steel DMR when I had tyres that would rotate fine when on a workstand but when riding the bike they rubbed over every bump.

The rear one lasted one lap of follow the dog before I brought a Nevegal. In that mere 7 miles or so the pain had worn through on chain and seat stays ant there was a very slight groove!

Well I’ve been on the look out for a cheap pike or such like for a while, so hopefully if/when I get one, then I’ll notice some big improvements.