[Closed] Talk to me about axle paths

i always assumed a rearwards path waas better for keeping speed up but a bugger to build.

shock and damping setup probably has a bigger effect than axle path.

Perfect axle path would be a perfect straight line, parallel to the axle path of the suspension fork on the bike.

Not easy to achieve indeed, but some have managed it... Done right, it negates any need for fancy clever shock technology.

[url] http://www.maverickbike.com/ [/url]

ok, I guess the VPP means the the pivot point can be way in front of the bike, giving a much breater radius on the arc of travel, nearer to a straight line. That makes sense.

Perfect axle path would be a perfect straight line, parallel to the axle path of the suspension fork on the bike.

Not easy to achieve indeed, but some have managed it... Done right, it negates any need for fancy clever shock technology.

Well you swallowed the Maverick marketing hook, line and sinker! 😀 The problem with the Maverick system is as soon as you stand on the pedals the suspension is much stiffer then when you are sitting down. Now I tend to stand up on the bumpy bits so I don't want the suspension to stiffen up at that point.

IMO the best axle path depends on what you are hitting, how fast you are going, whether you are seated or standing and whether you are climbing, sprinting on the flat or coasting downhill etc. This is why all suspension designs are a compromise.

I've two four bar bikes (an Enduro and a Marin Wolf Ridge). While they have exactly the same number of pivots, the ride characteristics are very different.

The Enduro feels extremely plush and the traction is excellent, however it wallows and squats under pedalling.

The Wolf Ridge feels very snappy under pedalling as the chain pull extends the travel somewhat, so it's ace for boosting off roots and things but the traction can spit without warning. The Marin is more sensitive to shock pressure too.

The axle path of the Spesh is supposed to be a straight vertical, while the Marin's is a flattened "S" according to all the information that I can find. As is always the case, the devil is in the detail and even two very similar platforms can behave very differently on the trail.

Even having ridden both bikes back to back in an afternoon, I cannot say definitively which setup I prefer. The Enduro is better on the climbs, especially in soggier conditions while the Marin is much more fun to ride.

Well you swallowed the Maverick marketing hook, line and sinker! The problem with the Maverick system is as soon as you stand on the pedals the suspension is much stiffer then when you are sitting down. Now I tend to stand up on the bumpy bits so I don't want the suspension to stiffen up at that point.

Hahaha

No, really, I was a massive sceptic, then I had a go on one... It just works! The BB is so close to the main pivot that it stiffens by less than 7% when you're stood up compared to sat down (someone on I think MTBR forums did an independent study into it, was quite in depth).

What you've done is swallowed the "it looks totally different to everything else, therefore it must be crap" hype spouted by most people on internet forums... People who hate Mavericks have never ridden one. People who have ridden them love them!

as soon as you stand on the pedals the suspension is much stiffer then when you are sitting down

Interesting stuff by [url= http://www.zerode.co.nz/education.php ]Zerode[/url] about high pivot position causing the wheel to go back and up making it extra plush.

I do like the Zerode, it was the idea of a similar bike that got me thinking.

that's an interesting frame but at over four and a half grand its a tad expensive

That's £2300 at today's rate.
And that includes the Alfine and all its gubbins, so its not [b]too[/b] obscene when you consider a SC Nomad costs £1850 and you've got to buy the drivetrain on top of that.

Wonder if it could take an Alfine-11?

I haven't ridden one so cant really comment, but in the vid the bottom bracket moves loads because its connected to the rear end. How weird would that feel!? Surely it will throw you all over the shop?

Looks like they have caused problems by trying to fix problems.

good point. I'm on my phone so can't check out the pics too well but I assume an 11 would fit but you'd need some modifications to the hub.

Et voila - http://www.santacruzbicycles.com/company/index.php?

That maverick rear suspension looks very much like a variation of the unified rear triangle. You can even see in the video on their website that the pedals are not isolated from the bumps coming through the wheel, you may as well be on a hard tail if you're stood up on the pedals.

edit : Flow beat me to it.

er sorry - this one should be right
http://www.santacruzbicycles.com/company/index.php?joe=1#joe0807.php

cheers for the link hepstanton, I'll have a read later.

Ahhh, great minds julians 😉

That maverick rear suspension looks very much like a variation of the unified rear triangle. You can even see in the video on their website that the pedals are not isolated from the bumps coming through the wheel, you may as well be on a hard tail if you're stood up on the pedals.

The bottom bracket moves, but not so much you notice it. It is not directly connected to the back end at all, it is a fully floating isolated part of the suspension system, and is part of what allows the exaggerated rearward movement of the axle path on the frame.

As for how much it moves, the ML8 has 165mm of rear wheel travel. The BB moves back and up by approx 15mm at full compression. How the hell is that like riding a hardtail? You've still got 150mm of suspension travel relative to the movement of your feet!

I will reiterate, the suspension on a Maverick stiffens by less than 7% when you're stood. If you set the suspension up so you can just about bottom it when you're sat on the seat, you're still going to acheive 93% of full travel when you're stood on the pedals over the same compression. It is barely noticable at worst.

Any doubters are more than welcome to have a go on my bike to see how it rides, I guarantee you'd be pleasantly surprised. When I first saw the frames 10 years ago, I just dismissed it as a URT. I had a go on one, it is nothing like a URT in the way it rides or performs. The heavily rearward axle path helps it both climb and descend like pretty much no other bike with the kind of travel it has...

So you have one Mboy?

I want a play!

I guess the main point about axle paths, pivot design and F/S design in general is that different types suit different people. It comes down to trying out the bike for the type of riding you do in the areas that you tend to ride in.

Whatever the magazines or brochures say about axle paths and its efficiency, it's only in your real world riding environment that you'll discover whether it works for you.

For instance, some suggest that a vertical axle path is the best, but few rocks and roots are perfectly square shaped so that may not suit.

Some say up and forwards is best but then there may be an issue with chainsuck or somesuch.

Also, some systems ramp up under breaking so the axle path itself becomes less relevant than the ability of the system to operate when under braking over gnarly terrain.

If you need to slow down some on descents then a system that avoids this might suit you better:).

The positions of the bearings and the loads that are placed on them under braking, pedalling and over obstacles, all affects how long they last and how much you spend on replacing the parts when they wear out!

I'm sure some will say that it therefore makes sense to only have one bearing. Personally, I think that whatever you choose, it just needs to work for you. If the set up avoids putting heavy strain on multiple bearings they'll last just as long:)

The nub is, you tend to spend more on the systems that are considered to be more effective and efficient. Patents etc enable the manufacturers to ensure that this remains the case.

Some rely on technology, some rely on physics. All of them rely on the bearings to hold it all together!

Once you've tried several bikes out (if you've not done so already) you may well find that axle path is not the most important aspect for you. Geometry may be more relevant or a particular spec or weight target or robustness.

In my experience, people's choice in bikes comes down to much more subjective things like looks, reputation, spec, bling factor and how impressed their mates will be:).

There are so many lovely bikes out there that people usually wish they could afford to have several bikes (which would probably all have different axle paths and suspension designs) - it's just not usually financially practical or conducive to a happy wife!

I once designed a front suspension system which had a j shaped path the initial rearward movement helped the wheel over stuff but it dived under breaking it only had 100 mm of suspension movement but could ride up curbs without unweighting the front It was the why're Preston
It later went on to get a rear end with a similar s shaped axle path ( after I had left the company)

I recently helped do a world cup dh bike with a single pivot linkage driven shock we looked at many systems and decided that there was so little difference on the axel path that it wasn't worth the possible patent infringements or the complexity of vpp designs , but the pivot placement is critical as is the shock ratio and the change of ratio driven by the linkage

But i am currently riding a full rigid 29er. Only because it's 11% better than the smaller brother

edit

I once designed a front suspension system which had a j shaped path the initial rearward movement

You designed Girvin Cross Links!?

Nope try again

Nope, can't think.

A clue?

Think ugly really ugly

Whyte PRST, about as ugly as you could ever make a bike.

Plus Fours weren't they?

Think ugly really ugly

Anything to do with Whyte's system (from the late 90s I think)?

[url] http://www.mtbr.com/cat/bikes/bike-full/whyte-designs/prst-1/prd_358250_95crx.aspx [/url]

Of course, beauty is always in the eye of the beholder!

You beat me to it flow! I was busy finding a link:)

I thought that F1 bloke (ex Benetton) designed the Preston?

http://www.whytebikes.com/wp-whyte/?p=6. I also worked at Benetton F1

No way, WTF are you doing on this shite hole of a forum?

There are some people on here who are worth listening to

Shame they don't have a listen too list, you would be on it.

So what world cup bike did you help design if you don't mind me asking, Sir Ade?

What you've done is swallowed the "it looks totally different to everything else, therefore it must be crap" hype spouted by most people on internet forums... People who hate Mavericks have never ridden one. People who have ridden them love them!

Good theory. Except I have ridden one. Admittedly it was the ML7, but even when set up properly I found it really harsh on rocky descents. It did climb really well though, I'll give you that. I also had a riding buddy with a Klein Palomino (same design) and he said the same; loved it on singletrack , hated it on bumpy descents when you have to stand up.

Nukeproof scalp with Brant

Cheers chaps.
Interesting comments and thoughts.

Here's one back: if the chain-growth and tension is the major point for pivot-placement, why doesn't someone make chain-tensioners/mechs with linear/variable rate springs to counteract the effect? Or have they?

because it affects the top chain run not the bottom

as above, its not just about the rear wheel path. when I was looking at a play frame, there were a bunch of fully floating designs (ie intense ss) and some faux bar links (pretty much everything else). the fully floating designs were more 'active', as there's more opporunity to tune the shock ramp up. however, they were also generally more flexy at the back end compared to a faux bar link, by nature of having 2 pivots between the rear wheel and the front triangle.

but yeah, a line that runs kinda parralel to the front fork is good. I'm not convinced that maveric design does it. MBUK reviewed their 'freeride' frame, and said it was naff, as whilst the pedals moving around didn't affect the xc/am frames too badly (due to the short amount of travel), on a larger travel bike the movement was distracting.

Incidentally, I never understood what was wrong with URT. yeah it stiffens up when you stand, but I'd actually like that on a bike. I never sit down on big hits, so it'd allow me to have a plusher ride when sat, then stand up for either cranking along (stiffer sus is better) or taking big hits (stiffer sus is better)...

thepodge - why not increase the tension in the bottom run to balance it out?

My belt-drive bike is set at fairly high tension (although not as high as recomended by Gates) and it doesn't affect pedalling.

thats because the tension isn't varying.

URT wasn’t a success for many reasons but partly because it only works when seated and lots of people stand or unweight their saddle and still want suspension to be active. Having it lock out when you stand means you’ll not get the benefits of increased traction and tracking that suspension brings.

I once did a URT design that had the pivot just behind & below the BB as opposed to the usual above and in front. The thinking was that the difference between seated and standing would be reduced but I’d get more travel on bigger hits where I naturally stand or unweight the seat in faster rockier areas and less travel / tighter suspension when seated and pedalling in smoother slower areas. Kind of like a hardtail with big hit capability.

Increasing the tension in the bottom run of the chain wouldn’t make much difference. The force carried in your chain is between the pedal and the ground, through your rear wheel, not so much the whole chain as a loop.