[DanielV]

What's the pros and cons with these two kind of forks?
As I see it, the normal fork, like the RockShox Boxxer, has a lower point of gravity and has a less problems with dirt, mud ect. Where as the upside-down fork, like the White Brothers Groove 180 & 200, seems to be a lot stronger in its construction. I've also read that it "... decreases the unsprung weight of the bike and improves its handling." over the normal fork design.

Anyway, I was just wondering and thought that it would be interesting to hear you peoples view on this.


Daniel...

 

[pinkshirtphotos]

you mean inverted fork?

 

[DanielV]

you mean inverted fork?

I'm not sure what you mean by "inverted", but tjeck the links to see the two different kinds.


Daniel...

 

[Jm_]

Simply, the inverted fork will support longer travel with better bushing overlap. It will suffer more from lateral flex, but it will be stiffer in for-aft flex, although this is only due to the size of the uppers and you can simply make the stanchions bigger in a "right side up" fork and get the same result.

It used to be that anything around 7" or more required an inverted design, hence the dorado, shiver, stratos S8, etc. Due to the relatively small size of the stanchions used on mountain bikes, these forks ended up being fairly flexy compared to the right-side up forks. Without the brake arch, there's a huge distance in between the axle and the crowns, and the "flex" occurs at the weakest point, which is where the stanchion tubes go into the uppers. This is the exact point on a normal fork where the brake arch is mounted and it makes a huge difference.

To get around the limitations of the inverted forks, most of the fork manufacturers have just made the stanchions bigger (except for rockshox), or they've extended the lowers a bit. This gives them adaquate bushing overlap, and even though it may be a little less, 4" of bushing overlap with 40mm stanchions will be stiffer than 5" of overlap with 30mm stanchions.

I believe the "unsprung" weight theory with the inverted forks is a myth. There are those that say because there's no fork lowers, that the inverted fork reacts to bumps better. What doesn't make sense is that there's oil, stanchions, dropouts, axle, hub, spokes, disc brake, inner tube, rim tape, rim, and the tire, which are all "unsprung" weight. Take the difference between fork lowers (usually pretty light) and the stanchions, lower internals, dropouts and oil that is in the bottom of an inverted fork, and then compare that difference to the total unsprung weight. What you see is that it's a very insignificant weight. I would attribute better performance in some inverted designs due to better lubrication. The oil sitting on top of the seals will provide better lubrication to the legs, vs. in a right side up fork.

That is also a negative though, because if you blow a seal, then you loose all the oil and it can spray your disc rotor with oil and then you got no brakes.


A sample math problem would be as follows;
Fork lowers on non-inverted fork maybe 900g
Difference between lower half of an inverted fork (dropouts, oil, internal parts, etc) maybe 450g

Now you have 200g for hub, 100g for axle, at least 300g for brake, 700g for DH rim, 30g rim tape, 200g spokes, 30g nipples, 400g DH innertube, 1400g tire, and add it all up; 3360g.
Then add 900g to that total=4260g
add 450g to the same total=3810g

Difference in unsprung weight? 11%

I think I'm being very generous too, because those cast magnesium fork lowers are usually VERY light, and there's still a lot of hardware and stuff on the lowers of inverted forks, I didn't even think about fork guards either.


Also, some companies like Avalanche and White Brothers do not have the machines to make cast-lowers, such as you find on the big companies like marzocchi, RS and manitou. So you can turn aluminum in a CNC machine to make crowns, uppers and tubes, but their costs would skyrocket for a while if they were to invest in aluminum/magnesium casting. Marzocchi and manitou and others come out with NEW castings for their forks all the time, and that cost would be HUGE to the smaller companies.

I've owned a few downhill inverted forks, and the "lateral flex" thing never bothered me much. I do notice an increase in the stiffness when using a good non-inverted DH fork, but then when comparing some of them to the boxxer which still has 32mm stanchions, the difference may not be that great in terms of the "stiffness", although they are likely to feel a bit different (big inverted fork would be far stiffer for-aft and boxxer may have a bit of an edge still in lateral stiffness). I've also owned the single crown inverted fork (shiver sc). That was a terrible idea in terms of structure. I've never had any problem with the stanchions getting dirt or mud on them (it just falls off as the fork compresses) or getting scratches because of rocks.

 

[Yeti]

and i would just give any of the new big company forks for an avy....drool

 

[frznnomad]

JM he didnt understand what we ment when seanmankiw said inverted fork do you really think hes going to understand that. although that is one hell of an explanation.

ohh and daniel when we say inverted were talking about avy's, whitebrothers, dorado's, and shivers.

 

[kidwoo]

White brothers are the best inverted forks made. Mine was stiffer than any other inverted fork out there. Those new ones look badass and I'm kicking around the idea of replacing my 888 with one.

 

[binary visions]

you mean inverted fork?

Do you have to try extra hard to be an ass, or does it just come naturally?

 

[DanielV]

JM he didnt understand what we ment when seanmankiw said inverted fork do you really think hes going to understand that. although that is one hell of an explanation.

ohh and daniel when we say inverted were talking about avy's, whitebrothers, dorado's, and shivers.

Hey, I'm not an idiot! I'm jut not used to calling 'em "inverted", but "upside-down" like when we're talking 'bout forks for motor bikes!

Do you have to try extra hard to be an ass, or does it just come naturally?

Nice point!


Daniel...

 

[greenhood]

I typically call that type of fork inverted, but for the sake of bugging rabbit guy, I will be calling it an "upside down" fork.

 

[mattmatt86]

hehehe, upside-down fork...

 

[siege]

so the answer is just get what you want and it doesn't matter?

 

[kidwoo]

Yes......upsidedown fvcking fork.

Before white brothers mad the dh3 and dh2 they were called the UD180 and the UD150.

The UD stood for "look at me I've been in the sport for five minutes and don't know sh1t about past terminology so I'm going to make fun of someone for using an accepted term"

"UD" was shorter to put on the sticker.

 

[binary visions]

Yes......upsidedown fvcking fork.

Before white brothers mad the dh3 and dh2 they were called the UD180 and the UD150.

The UD stood for "look at me I've been in the sport for five minutes and don't know sh1t about past terminology so I'm going to make fun of someone for using an accepted term"

"UD" was shorter to put on the sticker.

kidwoo for teh win.

 

[monkeyboy424]

kidwoo for teh win.

for realz
:biggrin:

 

[SteezyWeezy]

Yes......upsidedown fvcking fork.

Before white brothers mad the dh3 and dh2 they were called the UD180 and the UD150.

The UD stood for "look at me I've been in the sport for five minutes and don't know sh1t about past terminology so I'm going to make fun of someone for using an accepted term"

"UD" was shorter to put on the sticker.

ohhhhhhhh, daniel, wipe up those tears
haha, this is a good greeting from RM

 

[frznnomad]

originally posted by DanielV
but "upside-down" like when we're talking 'bout forks for motor bikes!

except on motorbikes, as you like to call them, they still call them inverted.

originally posted by kidwoo
The UD stood for "look at me I've been in the sport for five minutes and don't know sh1t about past terminology so I'm going to make fun of someone for using an accepted term"

geese kidwoo i think you officially scared the kid for life with that comment.

 

[ALEXIS_DH]

A sample math problem would be as follows;
Fork lowers on non-inverted fork maybe 900g
Difference between lower half of an inverted fork (dropouts, oil, internal parts, etc) maybe 450g

Now you have 200g for hub, 100g for axle, at least 300g for brake, 700g for DH rim, 30g rim tape, 200g spokes, 30g nipples, 400g DH innertube, 1400g tire, and add it all up; 3360g.
Then add 900g to that total=4260g
add 450g to the same total=3810g

Difference in unsprung weight? 11%

I think I'm being very generous too, because those cast magnesium fork lowers are usually VERY light, and there's still a lot of hardware and stuff on the lowers of inverted forks, I didn't even think about fork guards either.

i´d add something there.
unlike regular forks, in upside down forks the whole mass of the stanchions become unsprung mass as well.

that should offset substantially the arbitrary 450gr difference (if not completely).

 

[binary visions]

except on motorbikes, as you like to call them, they still call them inverted.

Would you guys stop picking on the terminology? "Upside-down" is a perfectly acceptable way of referring to these forks, as kidwoo made abundantly clear in his post - and at least a couple people misinterpreted him to be attacking Daniel, when he was clearly attacking sean and people like yourself who are utterly mistaken in your belief that the only way to refer to this type of fork is "inverted."

Google returns a million search results for the term "upside down fork" and only 700,000 results for "inverted fork" - gee, maybe that tells you guys something?

 

[DanielV]

Would you guys stop picking on the terminology? "Upside-down" is a perfectly acceptable way of referring to these forks, as kidwoo made abundantly clear in his post - and at least a couple people misinterpreted him to be attacking Daniel, when he was clearly attacking sean and people like yourself who are utterly mistaken in your belief that the only way to refer to this type of fork is "inverted."

Google returns a million search results for the term "upside down fork" and only 700,000 results for "inverted fork" - gee, maybe that tells you guys something?

THANKS!!!


Daniel...

 

[pinkshirtphotos]

bv's got the hates on me

 

[binary visions]

Just when you insist on trying to insult other people despite your total ignorance of what you're discussing. Completely ignoring the fact that you were wrong, did you think you'd just look cool by insulting someone who expressed himself perfectly well?

The reason this community is so much better than the Pinkbike or MTBR forums is because people who act like asshats are abused and if they don't stop, they're banned. Keep that in mind.

 

[skinny mike]

bv's got the hates on me

no, bv just hates stupid people in general.

 

[bballe336]

except on motorbikes, as you like to call them, they still call them inverted.

No, they absolutely do not. Go on any MX forum, everyone talks about forks as "USD" or upside down. No one says inverted, only us mountain bikers do. Now stop heckling this guy for using perfectly acceptable terminology.

Now to add to this thread:

I don't think there is a discernable difference in small bump sensitivity between standard and usd/inverted forks anymore. The damping in the new standard forks is better than anything used in the usd/inverted forks. This is simply because in recent years manufacturers either haven't made usd/inverted forks or haven't changed what they are making. The bigger manufacturers are all making standard forks which get updated far more often because the larger companies sell more, test more, and sponsor more riders and get more feedback.

 

[kidwoo]

geese kidwoo i think you officially scared the kid for life with that comment.

That was aimed at people like you genius.


What geese have to do with it, I have no idea.

My upside down white brothers forks were the easiest to work on of any fork I had and are made to be user servicable. That's one of the great things about them. I could get it as smooth as a shiver but I had to make sure the uppers (that's the top part of an upside down fork) had either open bath or fork oil in them for lube. They're still the best made forks in terms of construction I've seen made for mountain bikes.

 

[Bearmntpicnic]

I love my dorado and luckly nockin on wood I have had no problems.

 

[blue]

My Dorado is flexy, but I don't notice it.

Good?

 

[greenhood]

I still ride my 2002 shiver-works great

 

[Jm_]

i´d add something there.
unlike regular forks, in upside down forks the whole mass of the stanchions become unsprung mass as well.

that should offset substantially the arbitrary 450gr difference (if not completely).

That's what I was trying to imply, add that up with lower internals and dropouts and the such, and it's going to be pretty much the same.

 

[dh_newbie]

Did anyone see this at US?

http://www.tech-in.com

 

[thaflyinfatman]

That's what I was trying to imply, add that up with lower internals and dropouts and the such, and it's going to be pretty much the same.

Yep - the inverted-forks-have-lower-unsprung-weight idea was mainly propagated within moto circles, where their lowers weren't one piece (ie no arch) like MTB ones are, and they were instead relatively heavy machined or cast things. At least as far as Boxxers go, I'd go so far as to say that the stanchions are actually heavier than the lowers (which are VERY light and I'm sure Marz/Fox lowers are very similar) - and that to invert the fork would actually increase the unsprung weight.

However I too think the unsprung weight argument is a bit of a fallacy - nobody claims to notice better suspension action when they go to lighter wheels, for example. On top of that, the variation in suspension setup is so massive with MTBs (due to the fact that the rider is a moving ballast and there is very low rigid sprung mass, unlike motorbikes) and so many people do such a terrible job of setting up their suspension, that I think unsprung weight is a loooong way down the list of priorities for mtb fork performance.