[Lelandjt]

Does the 1st gen Demo use a rear wheel where the rim isn't centered on the axle? I just put my friend's wheel in my truing stand and it is dished way over to the non-drive side. Was about to dish and true it and then remembered that some DH bikes have offset rear ends where the rim has to be like this to sit in the middle of the frame.

 

[DirtyMike]

Yes, 6mm

 

[Lelandjt]

I wish they wouldn't do that. Makes trueing a pain. Thanks though.

 

[kidwoo]

I wish they would quit saying it's 6mm


It's more than that.

 

[DirtMcGirk]

Is it a big deal if you run a regular dished wheel in these frames?

I ask because I have Bridget's bike set up that way, and while it put me off some that the wheel wasn't centered in the frame, I let her ride it and it was not a BFD.

 

[ridenorcal]

its not the end of the world, its just a little funky. I believe it is a 10mm dish to properly offset it, at least on the newer ones.

 

[DirtyMike]

Its not so much you cant true it out, no need for spoke swapps or anything like that, you just have to dish it for the demo frame, that is all. I actually have a spacer that goes on the end of the hub when you put the wheel in the truing stand just for trueing Demo wheels.





EDIT.... By the way, the rason they do this, is to add some angle to the Drive side, IE reducing dish as some would call it. It actually makes the wheel a bit stiffer. Other bikes have just caught up to the 150 hub idea though

 

[xjvince]

Bighits are the same way. It makes a stronger wheel and provides more tire/chain clearance.

 

[Lelandjt]

I guess I can see it on the bighit (cheaper bike that people may want 135mm hubs for) but this is stupid on a full-on DH bike like the Demo. That spacer for trueing would be sweet to have if this was my bike.

 

[dilzy]

Running a 135 rear end means you can run a lighter hub. It also means you can run 73mm cranks which are lighter and more importantly means the pedals are closer together.

There are also more crank options in 73.

 

[kidwoo]

Running a 135 rear end means you can run a lighter hub. It also means you can run 73mm cranks which are lighter and more importantly means the pedals are closer together.

There are also more crank options in 73.

eggsakary


It's stronger than a traditional 135, and lighter than a 150 with more parts options.

Personally I wish every frame maker would do this.

 

[ohio]

Haven't owned a Demo, but it should be 7.5mm in reduced dish and you want a 15mm spacer to set it up in your truing stand. Not sure where 6mm would come from...

edit: and I agree with woo. I think it is a much better solution than a 150mm hub that is heavier and more expensive and just has a bunch of extra space on the non-drive side. This is stiffer, lighter, cheaper, and has more options.

 

[davet]

Running a 135 rear end means you can run a lighter hub.

150mm hub that is heavier and more expensive

There's about 13 grams difference (Hope Pro II) between 135 & 150 hubs and the price is usually the same, if anything the 135 is a bit more (Universal Cycles)

I doubt even the most obsessed weight weenie could even feel that with a hub in each hand, let alone mounted on a bike.

 

[kidwoo]

There's about 13 grams difference (Hope Pro II) between 135 & 150 hubs and the price is usually the same, if anything the 135 is a bit more (Universal Cycles)

I doubt even the most obsessed weight weenie could even feel that with a hub in each hand, let alone mounted on a bike.

don't forget longer spokes



If your prices are correct, that's the first time I've ever heard of a 150 being the cheaper option.

Still.....135s are made by everyone. Your options are much broader beyond "dh specific" hubs as well. I still think it's a great system. And you can switch wheels back and forth fairly easily between more bikes....especially something like a dirtjumper. I can redish one of those wheels in about 20 minutes, it's not like it's that big of a deal.

 

[MDJ]

Running a 135 rear end means you can run a lighter hub. It also means you can run 73mm cranks which are lighter and more importantly means the pedals are closer together.

There are also more crank options in 73.

I'm not so sure it's that important for DH, like it may be on a road bike. If you ride with a bow-legged style like Hill then I think the wider pedal spacing would be better and give more stability. Maybe for someone like Peaty with the knees-over-the-toptube style if may be better to have them closer.

 

[kidwoo]

It just means your stance is narrower and you're less likely to hit your pedals.


Since getting a newer dhr with a 150/83 setup, I have to say, I actually prefer the slightly wider stance. Makes you feel all manly and stuff airing out the boys.

 

[dexterq20]

I wish they would quit saying it's 6mm


It's more than that.

Haven't owned a Demo, but it should be 7.5mm in reduced dish and you want a 15mm spacer to set it up in your truing stand. Not sure where 6mm would come from...

How do you guys figure? The owners' manual for my '06 Demo 8 very clearly states that the rear wheel offset is 6mm.

 

[DirtyMike]

How do you guys figure? The owners' manual for my '06 Demo 8 very clearly states that the rear wheel offset is 6mm.

Yeah I got the 6mm from my Speccy rep, pretty sure thats what we are using to get the wheels correct. But Like i said before, he gave us the tool for it.

 

[DirtyMike]

Running a 135 rear end means you can run a lighter hub. It also means you can run 73mm cranks which are lighter and more importantly means the pedals are closer together.

There are also more crank options in 73.

Yeah.... Try getting the chainline correct with 73mm RF cranks then see if you can really run 73mm cranks. Not that is is hugley off on these bikes, but alot ends up with a 73/68 BB cup and an 83mm crank with a couple spacers. Race face has an actual setup just for this

 

[ohio]

The offset 135mm hub should NOT be run with a 73mm chainline. You're spacing out the drivetrain 7.5mm (or 6mm... either way the following is true) in the rear when you offest the hub, so you need to do the same to your whole chainline. If the demo doesn't run an 83mm BB, they should be supplying it with a spacer to fit 83mm cranks onto the 73mm shell, which is only doable with hollowtech II style external bearings.

 

[DirtyMike]

Hollowtech as in shimano only?????


If thats what your saying, thats not true, Raceface also makes a kit for it.

 

[Udi]

The offset 135mm hub should NOT be run with a 73mm chainline. You're spacing out the drivetrain 7.5mm (or 6mm... either way the following is true) in the rear when you offest the hub, so you need to do the same to your whole chainline. If the demo doesn't run an 83mm BB, they should be supplying it with a spacer to fit 83mm cranks onto the 73mm shell, which is only doable with hollowtech II style external bearings.

That's not correct, the specialized bikes actually have an offset rear triangle, the whole point is so you can have a zero-dish wheel build (obviously this is hub dependent, but it ends up working out correctly with most), while still keeping your 135mm hub and 73mm crankset (and BB shell).

Like kidwoo hinted, the offset is actually not 6mm either, I'm not sure what the 6mm refers to but the actual amount you need to offset the rim on the hub is 10-12mm (from memory).

 

[kidwoo]

How do you guys figure? The owners' manual for my '06 Demo 8 very clearly states that the rear wheel offset is 6mm.

I don't 'figure'. I look at the fackin wheel once it's in the frame.

You believe everything a manufacturer tells you? If so, NEVER by a marzocchi product.

Hell man, half the guys at specialized writing this crap believe their company makes bikes with vertical axle paths and completely brake neutral suspension.

The offset 135mm hub should NOT be run with a 73mm chainline. You're spacing out the drivetrain 7.5mm (or 6mm... either way the following is true) in the rear when you offest the hub, so you need to do the same to your whole chainline. If the demo doesn't run an 83mm BB, they should be supplying it with a spacer to fit 83mm cranks onto the 73mm shell, which is only doable with hollowtech II style external bearings.

Meh.

I ran both. The 73 shifted better. Believe it. Also remind yourself what 7mm looks like next to a cassette.

 

[Udi]

Yeah that's because it's actually designed to work with + give the correct chain line with 73mm cranks (I'm talking about the demo8 / bighit / p-series bikes with 135mm and ASR here). I'm guessing ohio hasn't owned one of those bikes, hence his post. I've owned all three haha.

 

[Dogboy]

That's not correct, the specialized bikes actually have an offset rear triangle, the whole point is so you can have a zero-dish wheel build (obviously this is hub dependent, but it ends up working out correctly with most), while still keeping your 135mm hub and 73mm crankset (and BB shell)

Okay. Speaking from experience here being a former Demo 8 owner. If you have a zero-dish 135mm rear wheel, the ONLY way you can make the center of the rear wheel align with the center of the bike (so it will track properly) is to move the hub over to the drive-side. This WILL increase the chainline by the offset - 6-10mm depending on who you believe. Regardless, to achieve a PROPER chainline you must use a 56-57.5mm chainline crankset. Will it work with a 50mm chainline crankset? Yes. Is it ideal? Depends on where on your cassette your chain spends most of it's time. If it is in the smaller (higher gear) cogs, you probably won't notice any detrimental effects. If it is in the larger (lower gear) cogs, your cassete, chain, and chainring WILL wear at an accelerated rate. Fact.

 

[kidwoo]

Yeah that's because it's actually designed to work with + give the correct chain line with 73mm cranks (I'm talking about the demo8 / bighit / p-series bikes with 135mm and ASR here). I'm guessing ohio hasn't owned one of those bikes, hence his post. I've owned all three haha.

Specialized claims you 'need' the wider BB. At least with the newer demos. I never owned a first gen so never paid attention to what was recommended.

Either way it's bs.

 

[DirtyMike]

I just set one up this past monday, you do indeed should be using the wider crankset. Even the older models, it was never a broblem back then, they just came with a wider BB spindle. It works with the 73's, but it isnt how it is supposed to be. Shimano and Raceface both have addressed this issue, and both have a method for fitting the 83mm cranks on the 73 shell.

Will it hurt the bike to run a 50/51mm chainline?..... no
Will you wear out the drivetrain faster?.........Only thing we have been seeing wearing faster than it should is the chain.


Should you worry about the chainline on these bikes?..... Not to much, unless your racing and riding Daily. but if your not dont sweat it, it still to this day amazes me how many bikes are out nowadays with an incorrect chainline.

Should you have your bike properly setup.... Of coarse, but if it works who gives a ****

 

[davep]

all sides of this arguement actually make sense if you think a little bit about the true chainline of a certain hub versus what the current cranks offer.

A non-offset 135 rear is exactly a 47.5mm chainline. A 150 rear is exactly a 55mm chainline.

Current external cranks dont offer these chainlines due to bearing width. All current (external) 68/73 mm cranks give at least a 50mm chainline (new saint claims 50.4)....and 83mm cranks are at least 56 or 57 (new saint lists 57.9mm).


Ok, now look at the Demo..135 rear dictates a 47.5mm chainline. Add the offset (officially 6mm) and you get a proper/correct chainline of 53.5mm.

Now of what is available currently, either 50 or 57mm chainline cranks, the Demo sits right in the middle...so flip a coin.

Keep in mind, that when Spec designed this ofset rear, ISIS was still the (only) crank choice, so available chainlines at that time were the correct 47.5 and 55mm. In that case, the wider (128mm spindle bb) would have provided a more 'correct' chainline.

 

[EVRAC]

Yes it's designed to run the wider chainline. If the cassette is shifted over, then of course the chainrings should be as well.

Yes the offset is exactly 6mm. If you measure it with a wheel dish tool by setting it to zero on one side and then flip it around and check the other side, you are doubling the error, and it will look like it's out by 12mm. Set the dish tool on a comparable, but normal wheel and then measure the offset wheel and you'll see the 6mm.

I think it is a good design.

 

[davep]

....

where are the pedals.....???

 

[EVRAC]

where are the pedals.....???

Check out near the bottom of this article:

http://www.nsmb.com/page/s/2641/company-profile-knolly-bikes

 

[Udi]

all sides of this arguement actually make sense if you think a little bit about the true chainline of a certain hub versus what the current cranks offer.

A non-offset 135 rear is exactly a 47.5mm chainline. A 150 rear is exactly a 55mm chainline.

Current external cranks dont offer these chainlines due to bearing width. All current (external) 68/73 mm cranks give at least a 50mm chainline (new saint claims 50.4)....and 83mm cranks are at least 56 or 57 (new saint lists 57.9mm).

Ok, now look at the Demo..135 rear dictates a 47.5mm chainline. Add the offset (officially 6mm) and you get a proper/correct chainline of 53.5mm.

Now of what is available currently, either 50 or 57mm chainline cranks, the Demo sits right in the middle...so flip a coin.

That's interesting, I never had any shifting issues with my spesh ASR bikes (all ran 73mm hollowtech II cranks), however I did burn through e13 chainrings quite quickly. Your post might explain that? Since switching to a sunday my new chainring still looks pretty new after over a year.

Also, I thought 150mm bikes were supposed to run a 57.5mm chainline, I was told that that's why sundays used FSA (and now shimano) cranks because truvativ only offered their holzfellers in a 56mm chainline, which didn't work so well with them.

 

[davep]

That's interesting, I never had any shifting issues with my spesh ASR bikes (all ran 73mm hollowtech II cranks), however I did burn through e13 chainrings quite quickly. Your post might explain that? Since switching to a sunday my new chainring still looks pretty new after over a year.

Also, I thought 150mm bikes were supposed to run a 57.5mm chainline, I was told that that's why sundays used FSA (and now shimano) cranks because truvativ only offered their holzfellers in a 56mm chainline, which didn't work so well with them.

Yea, chainlines have gotten confusing and sort of lost thier meaning as things (cranks) start to move to 'within a few mm of what they truely should be'.....and some frame mfg just make up whatever chainline they want with no regard to what is 'standard'....

Go back and look at ISIS or square taper chainlines. they were always 47.5mm (for a 3 ring MTB set-up) ...or you can easily measure the offset to the middle of a casette and subtract from (135/2)...

Now add ((150 - 135)/2) = 7.5mm to the 47.5 and you get 55mm...or you can subtract half of a cassette from 75 mm...


I will say though, that since so many DH bikes are run in the smaller cogs most of the time, or have some larger cogs removed or locked out, that erring on the wider side for crank chainline should not be a big deal unless you do a lot of lower gear gringing on you're DH bike.

 

[Lelandjt]

On a multi-ring bike if you use 1st or 9th with your middle ring most people would say you are cross chaining and should expect rub and wear. Trying to use a 9 speed cassette with a single ring means you're gonna have pretty bad chainline with half your cogs. Adjusting the chainline just changes which cogs see a straighter chain and which ones are worse. I removed my 1st and 9th cog cuz using them ment rubbing and sometimes skipping since my chainring lines up just outside of my middle cog

 

[PhilipW]

Hey all,
Most of you have covered this so far, but the Demo should have a crankset designed around a 56mm chainline ideally.

Truvativ makes a Howitzer BB for 73mm shell and 56mm chainline...easy.

Raceface has a solution involving a 73mm BB, 83mm cranks/spindle and a bunch of those crank spacers that they use.

Shimano doesn't have any production offerings that would work perfectly with the Demo unfortunately. I've seen XT cranks fit on, but with our current-gen LG1 the super dropped downtube interfered with the Direct Mount bashguard so we had to run it bash-less. You could still run a full bashguard, SRS-style of course.

Cheers,
Philip @ e*thirteen

 

[Iridemtb]

Hey all,
Most of you have covered this so far, but the Demo should have a crankset designed around a 56mm chainline ideally.

Truvativ makes a Howitzer BB for 73mm shell and 56mm chainline...easy.

Raceface has a solution involving a 73mm BB, 83mm cranks/spindle and a bunch of those crank spacers that they use.

Shimano doesn't have any production offerings that would work perfectly with the Demo unfortunately. I've seen XT cranks fit on, but with our current-gen LG1 the super dropped downtube interfered with the Direct Mount bashguard so we had to run it bash-less. You could still run a full bashguard, SRS-style of course.

Cheers,
Philip @ e*thirteen

I have a demo 9. I am actually buying a 2009 saint crankset. I am buying a 73mm bb and a 56mm crank. I am also buying a race face retrofit kit. Shimano said they will be coming out with a new option to buy a crank and bb only in a week, and that was a week and a half ago. Then I intend to buy a e-13 srs guide and bash.

 

[NJHCx4xLIFE]

I have a demo 9. I am actually buying a 2009 saint crankset. I am buying a 73mm bb and a 56mm crank. I am also buying a race face retrofit kit. Shimano said they will be coming out with a new option to buy a crank and bb only in a week, and that was a week and a half ago. Then I intend to buy a e-13 srs guide and bash.

You are talking about the race face converter kit right? Comes with some external spacers and the shorter plastic tube for inside the bb?

 

[ohio]

all sides of this arguement actually make sense if you think a little bit about the true chainline of a certain hub versus what the current cranks offer.

A non-offset 135 rear is exactly a 47.5mm chainline. A 150 rear is exactly a 55mm chainline.

Current external cranks dont offer these chainlines due to bearing width. All current (external) 68/73 mm cranks give at least a 50mm chainline (new saint claims 50.4)....and 83mm cranks are at least 56 or 57 (new saint lists 57.9mm).


Ok, now look at the Demo..135 rear dictates a 47.5mm chainline. Add the offset (officially 6mm) and you get a proper/correct chainline of 53.5mm.

Now of what is available currently, either 50 or 57mm chainline cranks, the Demo sits right in the middle...so flip a coin.

Keep in mind, that when Spec designed this ofset rear, ISIS was still the (only) crank choice, so available chainlines at that time were the correct 47.5 and 55mm. In that case, the wider (128mm spindle bb) would have provided a more 'correct' chainline.

There we go, that's what I was getting at. Udi, you're right I've never owned one of these... just doing the above math in my head.

 

[Iridemtb]

You are talking about the race face converter kit right? Comes with some external spacers and the shorter plastic tube for inside the bb?

http://www.jensonusa.com/store/product/BB407F30-Race+Face+Retro+Bb+Kit.aspx?sc=FRGL

^^^^^^^^^^^^^^^^^
That's what shimano told me to use.