Getting Twitchy ?

[trot]

Hi thrill seekers,

Advise on axles for buggies. Was out the other day buggying . Wind from 18 - 35ks @SSW.

Put my small 4mtr hornet up. Speeds from 30 - 40 +kph. Top speed for the arvo was 43.5 ks.

What i did notice was that a 40kph my buggy started to get skittish / Twitchy .

My wheels are a PL brought ten yrs ago, standard front but with a custom rear axle.

my weight then was 115kg, and today the same115kg.So the axles specs are

wheel / wheel (inside of tyre) 30mm stepping up to 40mm( The stepping from 30-40 mm

in length = 100mm). The total length of the axle minus wheels is 1.11mts.

Q: if i increased my axle length say to 1.4mts would the skittishness settle -or not?

Trot

[Clive]

A wider axle should make it more stable, I had a flexi and put a 1.4 giga axle plus extended the axle further back and it rode much better. The short buggies where you sit just about on top of the axle are always going to be twitchy, the back end slides out without much effort.

After a few setups I ended up with a big libre buggy, the difference in stability is astounding, if you want to go fast in a straight line big is beautiful, load it up until you lose your nerve, it doesnt get twitchy. if you're playing on a footy oval or in a limited space, small is sweet, there's not much point in having a big unit there.

Have fun.

[RobG]

It's a shame we can't introduce toe in/ toe out into rear axles. WIth my rally car designing hat on (my job), a couple of degrees of rear toe out will improve straight line stability hugely.

I'm guessing you don't want to bend your axle to achieve that though...!

Cheers - Rob

[Clive]

You could get toe in and out with these...you would have to run them at 90deg to the picture...

Or a bit of creative welding ....

Do you have a pic of your buggy?

[gum-nuts]

I have the PL 140cm gigastrong axle and longer side rails and it makes a big difference to how much power you can hold down

I couldn't afford a bigger buggy, now I'm not sure I would want something any heavier - though if Mr Hobbs wants anybody to look after one of his carbon buggies I would be willing

[Chook]

Not being rude trot, but is your axle already bent?

I know when I straightened Rob Lukin's PL axle, he reckoned it made a hell of a difference. Robbo generated a lot of pace with his PL.

They are pretty easy to straighten and are usually bent just outside the welds of the frame sockets.

Just use a long bit of steel or wood as a straight edge to mark with a texta where the bend/correction needs to happen.

I have lots of 200mm long bits of tube and pipe of all different sizes, that are split in halves lengthwise with an ultra fine cutting disc on the angle grinder. (Make one cut along the seam to get rid of the raised join if using pipe)

These are used when bending pipe or tube so as not to mark the tubes.

So just get a piece that goes over the axle, split it and use this to hold/protect the axle in the vice, while you slide a length of pipe over the other end to lever it back to true. A few wraps of electrical tape protects the stainless from the pipe marking it.

In this photo you can see the 200mm pipe bits (painted red so I can find them in my shed) I used them to straighten out these alloy wind surfer booms in my vice. If you look closely you will see the black texta line on top to keep them upright in the vice/clamp. I just shifted them along 25mm at a time and they ended up really straight with no dents. The black 2 have been straightened.

Sometimes it takes a few goes as it never straightens exactly where you want it to go and you don't want it to over bend.

Have a safe festive season guys, Chook

[BobM]

It's a shame we can't introduce toe in/ toe out into rear axles. WIth my rally car designing hat on (my job), a couple of degrees of rear toe out will improve straight line stability hugely.

I'm guessing you don't want to bend your axle to achieve that though...!

Cheers - Rob

I know I deliberately didn't order toe and camber adjustment when I ordered my Libre Dragster http://www.libre.de/Eng/prices/Dragster.html because the one I tested had this and the owner said that he spent ages setting it up initially and hasn't changed it since.

I also found that the (imaginary) line joining the footpegs needs to be close to the axis (line) of rotation of the steering. I had my footpegs too far back and this was causing wobbles even at low speed.

I see from other posts that you are in Sydney - see if you can tempt jdhot to a weekend at the beach.

BobM

[plummet]

little barrow wheel buggies are twitchy things at the best of times.

But.

30-40 kph is not that fast. I doubt its your buggy that's the problem.

it was simply a gusty day.

[Clive]

little barrow wheel buggies are twitchy things at the best of times.

But.

30-40 kph is not that fast. I doubt its your buggy that's the problem.

it was simply a gusty day.

Speed is a relative kind of thing, down at sandy point where the surface is flat and hard packed , 40khr is just a slow wander, get on a badly corrugated surface and 40 can seem life threatening . In a small park 40 can seem quite quick as a fence gets closer.

Twitchyness can be due to a lot of things, firstly the buggy ,the surface you're riding on, wind conditions, plus you're confidence level, the latter in part can add to over correcting when you feel you're losing control, making it worse.

A longer and wider wheel base is always going to be more stable, mine is somewhat adjustable.

I prefer the back wheels to break out first, then at least you still have steering, the further away from the rear axle and closer to the front axle then the harder it gets to break out at the back, you reach a point where the front will go first, if you watch some vids with some really good riders, you can see them just drifting constantly under load, but again it's usually a nice beach surface.

Get out to a nice beach with a few others and ask if you can try theirs and see the difference.

[Tiger37]

After a few setups I ended up with a big libre buggy, the difference in stability is astounding, if you want to go fast in a straight line big is beautiful, load it up until you lose your nerve, it doesnt get twitchy. if you're playing on a footy oval or in a limited space, small is sweet, there's not much point in having a big unit there.Have fun.

Ok. I am sure there has been discussion on this on EK before, but what is the recommendation for an "intermediate buggy"? I have had my PL F-Lyn second hand now for a year. It's a great little buggy and perfectly fits my requirements for a start up buggy to be used mainly on ovals in Canberra and fits in the back of my hatch back. However, on my occasional trips to the coast like yesterday at Broulee, although great fun, I wished I had a slightly bigger buggy with midi wheels. Is there a buggy that is one up from the PL but would still go in the back of a hatchback and be usable inland?!

[trot]

A big thanks for all the advise. I'm checking the straightness of the axle this morning. Will also look at getting a second axle

or i like clives idea of an adjustable axle. I'll also need to adjust my seat more towards the axle to increase the

load ratio over the axle.

Big thanks Dudes

Have a good safe break.

Trot

[Clive]

Just a quick picture to show the balance idea.

In my bug I'm sitting ever so slightly to the rear but not on top of the back axle. In mine the front wheel can be moved forwards in a number of slots, plus the footpegs can be moved forwards/backwards, this combined with moving the downtube in or out allows me to adjust the whole balance. I'm happy enough as it is, at 70khr it runs smooth, I let cris Italy have a ride in mine, he said he'd adjust a few things .... But then I'm a lot taller than he is.

I don't know how much adjustment you can do with yours but the wider axle and longer side rails suggested by gumnuts are a good start.

[Goz]

Ok. I am sure there has been discussion on this on EK before, but what is the recommendation for an "intermediate buggy"? I have had my PL F-Lyn second hand now for a year. It's a great little buggy and perfectly fits my requirements for a start up buggy to be used mainly on ovals in Canberra and fits in the back of my hatch back. However, on my occasional trips to the coast like yesterday at Broulee, although great fun, I wished I had a slightly bigger buggy with midi wheels. Is there a buggy that is one up from the PL but would still go in the back of a hatchback and be usable inland?!

Next step up would be a Libre Vmax V2 or Sysmic S2. I would go for Midi XL tyres instead of Midi's much nicer tyre for the little extra. You will probably have to partialy disassemble either to get it into a hatch back, not really a big job around 15 mins and about 7 or so bolts to break it into fork, axle, back wheels and frame.

[buggy boy]

This is my standard peterlynn with a Bigfoot lite on the front and asymmetricals on the rear.

It does feel like a different buggy when I swap out from the barrows which I use locally on the ovals to these larger wheels.

A definite improvement on soft sand, but with a short wheelbase still a bit twitchy.

[gum-nuts]

Standard comp with extended side rails, wide axle and back rest...

[plummet]

Speed is a relative kind of thing, down at sandy point where the surface is flat and hard packed , 40khr is just a slow wander, get on a badly corrugated surface and 40 can seem life threatening . In a small park 40 can seem quite quick as a fence gets closer.

Twitchyness can be due to a lot of things, firstly the buggy ,the surface you're riding on, wind conditions, plus you're confidence level, the latter in part can add to over correcting when you feel you're losing control, making it worse.

A longer and wider wheel base is always going to be more stable, mine is somewhat adjustable.

I prefer the back wheels to break out first, then at least you still have steering, the further away from the rear axle and closer to the front axle then the harder it gets to break out at the back, you reach a point where the front will go first, if you watch some vids with some really good riders, you can see them just drifting constantly under load, but again it's usually a nice beach surface.

Get out to a nice beach with a few others and ask if you can try theirs and see the difference.

True enough. I have my buggy set so I can lean forward or back and make the back berak first, have them both drift at the same time or the front drift..

PS if you want a solid feeling buggy. Go BIGFOOT!.

My barrow buggy is only used as a trailer now to tow the kids. The bigfoot comes out every time!

[Jason]

Before making any changes, what exactly do you mean by twitchy?

Is it the way your buggy steps out or does it feel like the steering is too quick?

Jas

[trot]

When i say twitchy the rear skips left & right and any adjustment

in steering causes fishtailing.

Trot

[nigel]

Your back end is breaking out first.

Bring the pull point (you) further forward, so more force is put on the front wheel.

Or extend the distance between you and the rear axle.

Or add more weight to the rear axle.

PL buggy's don't have much adjustment, so chances are your not going to get it any better.

A wider axle will not make much difference, it is great to stop the buggy going on two wheels, but I doubt it will help with the back end stepping out.

What surface and tyre, tyre tread are running?

[Jason]

I'm with Nigel, you need to pull your tow point forward until it breaks traction more evenly between the front and back.

Wider wont help, you need a longer buggy to slow the break out.

With the steering it's something you may get use to after more time. Other than increasing your wheel base length the only way to slow the steering is to increase the head stem rake but this would take a little engineering.

If all this fails you just need a longer buggy.

Jas

[andy666]

Yeah, the back end sliding out is just a trait of the short wheelbase peter lynn buggies. For freestyle guys or when needing to do tight turns in a park this a bonus. You can get used to counter steering a Peter Lynn buggy and just drift the buggy when over powered. But if you want straight line speed and stability a longer buggy, with more adjustment is the go.

[trot]

You mentioned that I might need a longer bug. I see different bugs but which bugs are good and which are not so good

re adjustment and are certain bugs designed for certain pursuits i.e. speed , jumps , drifting etc.

Trot

[Jason]

Light and short buggies are suited to jumping/freestyle and accelerate quickly.

Longer heavier buggies are faster as they hold more power and the wheels track straighter.

The only "bad" buggies I have seen are probably the Radsails as they simply aren't strong enough.