Peter – I don't know if you have followed this debate in the motorcycle press – I have over the years. "understeer" is sometimes used as the term for pushing the front but many folk in the motorcycle world follow the line I do and to reduce confusion prefer to call it "pushing the front" as as you agree its a totally different mechanism in bikes to cars"

You can get this phenomenon in a two wheeler without a significant slip angle if you have mismatched tyre profiles for example.

anyway – its a purists semantic argument and a long way from the OP.

Op – apologies for hijacking your post.

If you are running wide then more front grip or more camber thrust is needed. More wieight on the front, lean the bike more, better gripping front tyre, more rebound damping to prevent unloading of the tyre, steeper steering head angle ( more sag???)

Motorbikes do not do twisty singletrack, do they? They do fast long corners on smooth surfaces.

Some people really could start an argument with themselves 😀

Swiss – fast corners or tight slow ones?

All things being equal sounds like you have a slacker headangle than you had before. What frame is it/was it?

what happens to the ostriches when you get under steer?

It's a bit like watching that video of the rolling rally car the other day, but in slow motion, and the car is full of ostriches, and every time it rolls another ostrich comes flying out, and as each ostrich hits the ground it starts whooshing like a catherine wheel, and all the orange penguins who are watching the crash come running out with brooms and try and put the ostriches out by hitting them with their brooms, but the brooms just catch fire and the penguins panic and stat rolling around on the ground surrounded by exploding ostriches as the car rolls on and on spewing out ever more ostriches. – BigDummy (STW)

Molgrips – you are probably right that I am slower but what is wrong with my solutions?

Tron – the contact patch moves off the midline as you lean ( towards the edge of the tyre) and the as you initiate a left turn by steering right you move the contac patch from under the COG whixh is one o thereasons you then lean into a turn

A few more random definitions –

un·der·steer (ndr-stîr)
intr.v. un·der·steered, un·der·steer·ing, un·der·steers
To turn less sharply than the operator would expect. Used of vehicles, especially automobiles.
n.

intr.v., -steered, -steer·ing, -steers.
To turn less sharply than the operator would expect. Used of vehicles, especially automobiles.

Long winded and applied to cars, but the input/output is the same –
understeer is when the car won't turn any sharper, even if you turn the steering wheel more. At some point, the front end may start to grip less even when the steering is turned sharply and the result is the car continues in more of a straight line than a sharp turn. That is understeer.

And a slightly simplistic one for bikes
Sport: Motocross
Hide links within the definition
Show links within the definition
Definition
When a bike's front tires do not turn into a corner as well as the rear tires do.

And finally, the Oxford definition
understeer

• verb (of a motor vehicle) have a tendency to turn less sharply than is intended

None ramble on about turn angles etc (In fact I've not founbd one that does yet) it seems that it's all to do with the fron end sliding or a wider than expected turn. Very simple.

Need any more? 😀

prefer to call it "pushing the front" as as you agree its a totally different mechanism in bikes to cars"

ARRRRRRRGGGGGHHHHHHHHHHH!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

**Bangs head on wall**

Yes, it might be 'a different mecahnism' but the END RESULT is identical -The front end has less grip than the rear and slides, runs wide or turns less than expected.
That's the be-all-and-end-all of it. There is no more to it than that. However you get there, whatever you call it it's the SAME THING.

You take the stairs, I take the lift (Because I'm tired from banging my head and might start on yours in the stairwell 😉 ) but we both get to the top floor. You catch my drift?

Drift? HaHaa! Geddit? Understeer ….? Drift…..?
Ahem. Sorry.

😀

OP: ignoring all the debat, I've experienced "understeer" (bars crossing up in turns and bike going straight on), for me it's usually tyre related.

Look for something quite sticky and without straight line gaps laterally across the tread. Think spaced out blocky treads.

I quite like Kenda Blue Groove 2.35 in Stick-E compound for what it's worth. Both my bikes have them on the front.

If your runniong wide on corners. It sounds like it is simply technique deficit. slow down going into them. or improve your cornering style. i run wide often, usually going to fast.

PP – are you being deliberatly obtuse? You agree with me that a two wheeler and a 4 wheeler act very differently – the phenomenon that cause them to run wide is different and has different causes and solutions and you want to call it the same thing?

go and read up on some real experts on how 2 wheelers work.

Yes, it might be 'a different mecahnism' but the END RESULT is identical -The front end has less grip than the rear and slides, runs wide or turns less than expected.

And here is one of your mistakes / misunderstandings – Bikes can run wide and require correction without a loss of grip due to geometrical effects.

Its clear you don't actually understand how a bike steers

I think we can agree the cause is due to completely different dynamics. However, they are known by the same terminology. All press, books and literature refer to the same terminology. Your interpretation is different but that's you.

It's a bit like watching that video of the rolling rally car the other day, but in slow motion, and the car is full of ostriches, and every time it rolls another ostrich comes flying out, and as each ostrich hits the ground it starts whooshing like a catherine wheel, and all the orange penguins who are watching the crash come running out with brooms and try and put the ostriches out by hitting them with their brooms, but the brooms just catch fire and the penguins panic and stat rolling around on the ground surrounded by exploding ostriches as the car rolls on and on spewing out ever more ostriches

This has got to be one of the funniest things I've ever read! 😀

So after re-reading the OP all the same parts, just the frame has changed.

So three things spring to mind.

Your headangle is slacker which tends to slow the steerring but makes the bike more stable at very high speed (think downhill bikes)
Your wheelbase is longer again more stable at speed but could be slowing your steering in tight bends
You're sitting further back on the bike unweighting the front wheel giving you less grip.

That's what I reckon anyway.

I think we can agree

i very much doubt that

and that BigDummy quote is responsible for an awful lot of tea in keyboards across the nation

My God what a childish pedantic waste of typing. Even if understeer is not quite the correct term by some nerdy analysis we all know what he means FFS. Push, front washing a bit, lack of steering bite – whatever.

I'd suspect that the bike doesn't fit the same as what you're used to, maybe? Is it a bit longer? Is the seat tube more slack or the front centre longer? My first guess was fork too long.

HTTP404 – Member

I think we can agree the cause is due to completely different dynamics. However, they are known by the same terminology. All press, books and literature refer to the same terminology. Your interpretation is different but that's you.

actually not all books / press refer to the same terminology. I have followed this debate in the motorcycle press for years and many folk do not refer to running wide on a bike as understeer simply because it is a number of different effects with different and multiple causes and can be nothing to do with tyres losing grip. To call two different effects with different causes the same thing leads to confusion as can be seen on this thread

2 wheeler steering is incredibly complex with a huge number of factors effecting it and very many people do not understand it. Running wide can be caused by issues with grip, frame geometry , tyre profile, weight distribution and other causes. each can cause the bike to run wide and each has a different cure

I do apologise for the pedantic hijacking of the thread tho. I didn't mean to end up getting into such a row. I'll shut up now. sorry.

Back on topic!

It's when cornering at speed, the frame is less slack than the one before.

I'm perfectly willing to accept rider error it's just that i haven't experenced it before?

Hmm. OK, if you're sure it isn't slackness I'd take this as an opportunity to reinforce your cornering technique. So – really (really really) press down on the outside pedal, forcibly twist your body to face the way you want to go, lay the bike down more than you and look only where you want to end up, and believe the bike will stick!

And take some air out of the front tyre, unless you're already as low as you dare.

FULLY ON TOPIC:

I've scanned this thread so someone might have said this already.

I used to have a front end wash out feeling, the feeling that I was leaning into a bend and the bike went straight on for a bit before turning so you lose your precision of where you thought it was going. So after a chat with my fast mates I find that I corner better (define that) if I hang off the back a bit, sort of dig my back wheel in, feels more grippy and feels like the bike is going where I point it.

Some people really could start an argument with themselves

Calling sfb, calling sfb.

Can't be arsed to read all of this.

Try actively putting more body weight on the inside bar grip when cornering.

as expected:

Motorbikes do not do twisty singletrack, do they?

They do. They're better at it than bicycles too…

Going back on topic,

I've had understeer (front tyre washes out a bit as you turn) on my cove HJ when my stem was too long (100), I knocked it back to 70 and the problem went away.

Biggest tip I had (thx to AQR) to help going round corners was push down through the handlebars with my hand on the inside of corner.

Anyone who wants to know more about understeer / running wide and how 2 wheelers steer try: Motorcycle handling and chassis design: the art and science By Tony Foale

linky to relevant bit ( hopefully)that explains why calling motorcycle running wide understeering is unhelpful.

http://books.google.co.uk/books?id=84hF-qoR5I8C&pg=PT73&lpg=PT73&dq=Toany+foale+understeer&source=bl&ots=FYB2tGOfPf&sig=Fw1NnU8C4slEPxHV_xWGSudoe3M&hl=en&ei=3ptdS472D4X40wTX-d37BA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAkQ6AEwAA#v=onepage&q=understeer&f=false

toys19 – I think maybe the reason that works is in going a bit further back you are transferring all your weight down through the pedals, driving the bike with your feet. Well, ideally just one (outside) foot.

Contrary to what some people will suggest I recommend not thinking particularly about your hands or the handlebars at all – get everything driving down and through the BB and think in terms of turning yourself and the bike just following your lead.

The tyre isn't washing out, running swampthings, i'm just running wide?

sorry to tell you but it sounds like it's YOU that's causing the problem then.
try to choose better lines while cornering and commit to the corner more using your whole body, not sitting down and just turning the bars.

Weighting the inside bar grip seems counter-intuitive to me, I'd have thought it would make the bike more prone to washing out. Does that really work? Not that I go round corners fast enough for it to be an issue mind!

I would make sure sag is set right about 1/3 of total travel while in your riding gear is a good place to start
then work on you riding (body) position
just give that ago and see what happens

(what could possibly go wrong eh 😛 )

Weighting the inside grip works because it makes you lay the bike down more and the bike turns more forcibly. I generates counter-steer and keeps the bike laid over. As a general point though I don't find it especially useful to think about pressing down on the bars.

If the frame is less slack than before and the problem is high speed cornering then I'd say it might just be a characteristic of that kind of bike, you can't chuck it into the corner as hard as a nice slack head angle one. Try going in slower, you might carry a bit more speed out as a result?

what does it matter TJ if we all know what he means?

How many times have you ridden this new bike? You prolly just need to get used to it.

"Weighting the inside bar grip seems counter-intuitive to me, I'd have thought it would make the bike more prone to washing out"

It seems wrong but feels right. Imagine a right-hander…

Weight on left foot
Press on right bar down to tip the bike against the pressure of your weight on left foot – stay on top of the bike.
Compress sharply and the tyres grab making you turn sharp – careful not to high-side or get pinged into an unexpected left turn.

I'm a long way from perfecting this technique!

To the op – I've experienced what you describe and it was purely down to tire choice. Was pretty clear as I made no changes to the bike other than tires. Happens when I run a spiked or studded tire front and rear. No matter how hard you commit to the corner the back wheel grips too well and forces the bike wide. Swap your rear tire for a hard compound high roller which will let the back end drift predictably, the swamp thing up front will track nicely – works for me.

what does it matter TJ if we all know what he means?

Interestingly… the OP first said understeer and later explained what he meant as running wide. Which isn't understeer or the front pushing.

But… yes.

Couldn't tell you what my handlebars are doing during a turn, as a) I'm not looking at them, I'm spotting the exit of the turn, and b) I steer mostly with my feet and arse.

Interestingly, I was riding with mrmichaelwright up at Kirroughtree this summer, we're pretty evenly matched, he edges me on the descents, I can't mostly out-climb him, anyway he was pulling away from me more than normal, we stopped to talk about it and he was saying to me whenever you feel like braking in a corner, instead, look up, properly actively look at what you're doing, concentrate on it…You have to judge it very finely, helps no end with cornering.

a two wheeled machine is a two wheeled machine and physics doesnt change because we are slower and pedaling,,

i used to run the ohlins race service i used to explain it like this to riders front end pushing ( understeer) need more weight on the front rear end sliding ( oversteer) need more weight on the back

more weight on the front ( as we are talking understeer) can be acheived by either lowering the front ride height raising the rear or moving the rider forward,,

flashforward to me in another job ,, i have a whyte preston when i rode the prototypes i found them great but i felt the production ones didnt have enough weight on the front hence they had understeer , also tended to lift while climbing so my solution is both my prestons have 24 inch front wheels makes them great climbing and down singletracks IMO