# Truvativ Howitzer bottom bracket?



## XSL_WiLL (Nov 2, 2004)

I decided to go with an external bearing bottom bracket after my current ISIS bb dies (I'd give it about a month or two... ISIS bbs rarely last more than 6 months for me). I'd like to keep my current cranks though. The Howitzer bottom bracket is supposed to be compatible with ISIS cranks, right? And since the bearings are on the outside, it'll push my chainline out a little bit further, right? I know FSA is going to release one with 4 sets of bearings, but I think I remember it as being compatible only with FSA's crank to go with it. Soo... Does anybody know of any other bottom brackets I should take a look at? Thanks.


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## keen (Jan 13, 2004)

XSL_WiLL said:


> I decided to go with an external bearing bottom bracket after my current ISIS bb dies (I'd give it about a month or two... ISIS bbs rarely last more than 6 months for me). I'd like to keep my current cranks though. The Howitzer bottom bracket is supposed to be compatible with ISIS cranks, right? And since the bearings are on the outside, it'll push my chainline out a little bit further, right? I know FSA is going to release one with 4 sets of bearings, but I think I remember it as being compatible only with FSA's crank to go with it. Soo... Does anybody know of any other bottom brackets I should take a look at? Thanks.


 I went to Truvativ's website and got the impression that the Holzfeller cranks now have a Howitzer interface to match the new BB. Under crankset spec's the ISIS and Howitzer are listed seperatly. My guess is they woudn't interchange.


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## XSL_WiLL (Nov 2, 2004)

It says "Holzfeller ISIS Drive Cranksets" at the top. Soo.... ?


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## zedro (Jan 12, 2004)

keen said:


> I went to Truvativ's website and got the impression that the Holzfeller cranks now have a Howitzer interface to match the new BB. Under crankset spec's the ISIS and Howitzer are listed seperatly. My guess is they woudn't interchange.


 yeah, check this PDF .

However FSA has an external BB ISIS interface with standard chainline spacing (ie standard spindle length).


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## zedro (Jan 12, 2004)

XSL_WiLL said:


> It says "Holzfeller ISIS Drive Cranksets" at the top. Soo.... ?


 HOWITZER....not Holzfeller....theres no crank listed yet, only BBs

actually i read them as the same word at first too


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## keen (Jan 13, 2004)

zedro said:


> HOWITZER....not Holzfeller....theres no crank listed yet, only BBs
> 
> actually i read them as the same word at first too


 For 2006, the new Holzfeller raises the bar again. The new Holzfeller uses a brand new arm design made of AL-7050-TV. The result is a stronger, lighter and stiffer crankarm. Next, we combine this with our new Howitzer BB - Sounds like a Holzfeller w/ a Howitzer interface for 06'.


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## Tomasz (Feb 28, 2005)

*FSA Platinum MegaExo vs. Truvativ Howitzer vs. BMX-style 48T Spline*



zedro said:


> yeah, check this PDF .
> 
> However FSA has an external BB ISIS interface with standard chainline spacing (ie standard spindle length).


Second that: you can cross-check it by looking at it from the cranksets' perspective, so to speak; Truvativ's blurb follows: _The new Holzfeller uses a brand new arm design made of AL-7050-TV. The result is a stronger, lighter and stiffer crankarm. Next, we combine this with our new Howitzer BB. This BB set is built to take it with oversized, external mounted bearings._ That said you're righ, on the top it reads: "Holzfeller ISIS Drive Cranksets", apparently just to confuse us...

Incidentally, I've also been looking @ FSA Platinum MegaExo ISIS -- has anyone had a chance to test this product extensively? I'd be very keen to learn how it performed for you!

On a related issue, please check out / respond to this thread.

Cheers,
-Tomasz

PS As for proprietary desings in general, I'd feel a bit nervous to lock myself with a given set of [expensive] cranks into a specific bottom bracket, such as said Truvativ's Howitzer BB ...but then again, if open standards aren't delivering on the promise and there are better solutions out there...


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## zedro (Jan 12, 2004)

Tomasz said:


> PS As for proprietary desings in general, I'd feel a bit nervous to lock myself with a given set of [expensive] cranks into a specific bottom bracket, such as said Truvativ's Howitzer BB ...but then again, if open standards aren't delivering on the promise and there are better solutions out there...


 well it might depend, so far Shimano and RaceFace BB's are interchangable, maybe the FSA ones too. I find it odd they seem to provide the spindle with the BB for their model, but maybe they'll package it differently when its released for production.


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## caspar (Feb 2, 2004)

*SKF has a new ISIS BB in the works with a 10yr warranty*

I believe its at www.skfbike.com , theres writeup/teasers at www.bikemagic.com and www.singletrackworld.com , looks promising , but itll cost ya!! 
In the UK msrp is 85£ for the FR model , compared to 130£ for a complete Saint BB/Crank/Ring., Ouchhh. At those prices I doubt theyll sell alot.
I know what Im getting next ; SAINT , U just cant beat Shimanos prices when compared to what Ure getting (at least here in Europe) .
Cheers


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## zedro (Jan 12, 2004)

caspar said:


> I believe its at www.skfbike.com , theres writeup/teasers at www.bikemagic.com and www.singletrackworld.com , looks promising , but itll cost ya!!
> In the UK msrp is 85£ for the FR model , compared to 130£ for a complete Saint BB/Crank/Ring., Ouchhh. At those prices I doubt theyll sell alot.
> I know what Im getting next ; SAINT , U just cant beat Shimanos prices when compared to what Ure getting (at least here in Europe) .
> Cheers


 a bit late, ISIS is going the way of the square taper at this rate. It was kind of a flawed system to begin with, the tapered splines concept didnt quite pan out very well manufacturing wise.


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## NorKal (Jan 13, 2005)

zedro said:


> a bit late, ISIS is going the way of the square taper at this rate. It was kind of a flawed system to begin with, the tapered splines concept didnt quite pan out very well manufacturing wise.


So the reason we're all buying outboard bearing, cranksets now is _not_ because they are better (lighter, stronger, etc.) but because it's difficult (more expesive) to manufacture ISIS splines??? 

I don't buy it Z-man. Pleaz explaine.


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## zedro (Jan 12, 2004)

Khemical said:


> So the reason we're all buying outboard bearing, cranksets now is _not_ because they are better (lighter, stronger, etc.) but because it's difficult (more expesive) to manufacture ISIS splines???
> 
> I don't buy it Z-man. Pleaz explaine.


 the main problem is in order to make stronger BB spindles, you need larger ones. The result is you got more delicate bearings stacked in the same smaller space (SKF was trying to make a better bearing for the same problem). Since frame makers dont really want a new BB shell standard, the crankset guys decided to go outside the shell. The result: even bigger diameter spindles, bigger and stronger bearings, and a more efficient spindle/crank design (like using large diameter frame tubing). Now ISIS's primary flaw was the bearings due to the large spindle in a confined space, and this is why they are going outboard; the ISIS standard just happens to be not so great either (Shimanos non-tapered Octalink seems to have less interface problems). Native ISIS systems are usually fine (when well maintained), but start mixing and matching brands and some people get problems due to the difference in tolerances....i remember even reading this on a manufacturers site!

I dont think ISIS will totally dissapear, but i can see it being greatly marginalised. To me it doesnt make alot of sense that mtb cranks had the spindle integrated with the BB, when clearly its a fixed component to the cranks. It wasent originally like that, and BMX stuff doesnt follow that logic either.


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## eknomf (Jun 21, 2005)

I've looked at and installed a set of the prototype howitzer cranks and bb. The bb is basically an external bearing version on an isis bb. Because the bearings are outside, it is very wide and they had to cut down on the width of the splined section making for a lot less contact area than in an isis system. The cranks wrap in around the bb to make up for its width.

The pair we had were used for a day of dirt jumping and came back completely stripped out and destroyed at the splines. They may solve some of the bearing troubles of isis, but I think the howitzer stuff is still a pretty bad design because of how little contact area there is between the crank arms and bb. Plus, once you buy into it, I think you're stuck with the truvative system.


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## imridingmybike (Jan 16, 2005)

XSL_WiLL said:


> I decided to go with an external bearing bottom bracket after my current ISIS bb dies (I'd give it about a month or two... ISIS bbs rarely last more than 6 months for me). I'd like to keep my current cranks though. The Howitzer bottom bracket is supposed to be compatible with ISIS cranks, right? And since the bearings are on the outside, it'll push my chainline out a little bit further, right? I know FSA is going to release one with 4 sets of bearings, but I think I remember it as being compatible only with FSA's crank to go with it. Soo... Does anybody know of any other bottom brackets I should take a look at? Thanks.


I've been running the Howitzer BB with some '07 model Truvativ ISIS cranks for 6 months. The BB is designed to handle both 68 and 73 mil width frames - via spacers, and has enough room to accomodate a 73 mil frame with a chain guide. - you must be careful when installing to get these spacers right, or you can compress the bearings. When installed properly, they are trouble free.

The new Truvativ stuff looks good, works great and they back their stuff up with great cust serv (they're a sram company now, so that goes with out saying)


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## XSL_WiLL (Nov 2, 2004)

Soo... Bottom line... Is the Howitzer a ISIS bottom bracket or not? It's going to be paired with Bontrager Big Earls and Race Face Prodigy DH cranks.


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## imridingmybike (Jan 16, 2005)

XSL_WiLL said:


> Soo... Bottom line... Is the Howitzer a ISIS bottom bracket or not? It's going to be paired with Bontrager Big Earls and Race Face Prodigy DH cranks.


It APPEARS to be. But I just emailed their engineer asking him.

While the actual crank/bb interface may be fine - with those big ass bearings sticking out, there may be other clearance issues...

I'll let you know what they say.


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## keen (Jan 13, 2004)

XSL_WiLL said:


> Soo... Bottom line... Is the Howitzer a ISIS bottom bracket or not? It's going to be paired with Bontrager Big Earls and Race Face Prodigy DH cranks.


 ISIS = ISIS , Howitzer = Howitzer.


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## rpet (Jan 27, 2004)

I don't get why FSA decided to make this new Howitzer (monsterISIS) design. Why didn't they go outboard? They already have their own outboard stuff that is compatible with the other brands. I don't see any benefit in keeping ISIS around. I don't think Holzfeller/howitzer is going to be substantially lighter/stronger/stiffer than XT, though perhaps it will be lighter than a Saint set-up.

My $.02 is that FSA made a bad decision on this one. If the '06 Holzfeller arms were outboard-BB compatible I would be first in line to buy them.

Any ideas on why they decided to buck the trend?

-rob in NY


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## imridingmybike (Jan 16, 2005)

*No Go*



imridingmybike said:


> It APPEARS to be. But I just emailed their engineer asking him.
> 
> While the actual crank/bb interface may be fine - with those big ass bearings sticking out, there may be other clearance issues...
> 
> I'll let you know what they say.


Their engineer says they are not compatible.

Dang.


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## zedro (Jan 12, 2004)

rpet said:


> I don't get why FSA decided to make this new Howitzer (monsterISIS) design. Why didn't they go outboard? They already have their own outboard stuff that is compatible with the other brands. I don't see any benefit in keeping ISIS around. I don't think Holzfeller/howitzer is going to be substantially lighter/stronger/stiffer than XT, though perhaps it will be lighter than a Saint set-up.
> 
> My $.02 is that FSA made a bad decision on this one. If the '06 Holzfeller arms were outboard-BB compatible I would be first in line to buy them.
> 
> ...


 actually marketing wise making an outbourd ISIS was kinda smart, think of all the ISIS cranks out there that would benefit. People will be more likely to buy the FSA BBs if they want to keep their old cranks


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## rpet (Jan 27, 2004)

regarding FSA's MexaExo ISIS, I would agree; it's a good replacement part for those of us who still have ISIS cranks.

regarding Truvative's 06 Holzfeller (their top of the line FR/DH cranks) being this weird Howitzer-ISIS: I think it's misguided.

side note: FSA makes like 8 types of BBs now... kind of random.

-r


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## marsb (Jun 6, 2004)

rpet said:


> I don't get why FSA decided to make this new Howitzer (monsterISIS) design. Why didn't they go outboard? They already have their own outboard stuff that is compatible with the other brands. I don't see any benefit in keeping ISIS around. I don't think Holzfeller/howitzer is going to be substantially lighter/stronger/stiffer than XT, though perhaps it will be lighter than a Saint set-up.
> 
> My $.02 is that FSA made a bad decision on this one. If the '06 Holzfeller arms were outboard-BB compatible I would be first in line to buy them.
> 
> ...


I thought Howitzer was a Truvativ product, not FSA.


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## rpet (Jan 27, 2004)

Sorry - got them mixed up there, due to the 2 outboard ISIS designs confusing me. 

Anyway - I still don't see why Truvativ didn't switch the Holzfellers to "GXP" or whatever they're calling the thru-spindle & cups outboard style that Raceface, FSA and Shimano are doing.

TGIF!

-rob


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## Micnap (Aug 16, 2005)

rpet said:


> Sorry - got them mixed up there, due to the 2 outboard ISIS designs confusing me.
> 
> Anyway - I still don't see why Truvativ didn't switch the Holzfellers to "GXP" or whatever they're calling the thru-spindle & cups outboard style that Raceface, FSA and Shimano are doing.
> 
> ...


I agree that GXP Hussefelts and Holzfellers would make more sense. The taper of the Howitzer splines looks iffy. By the way, does anyone know if FSA will make the V-Drive Extremes w/ outboard bearings? MBA had a review of the Foes Fly recently and if you look, the V-Drives on that bike are outboard, but FSA's website doesn't show these at all. What's up?


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## Huck Banzai (May 8, 2005)

Khemical said:


> So the reason we're all buying outboard bearing, cranksets now is _not_ because they are better (lighter, stronger, etc.) but because it's difficult (more expesive) to manufacture ISIS splines???
> 
> I don't buy it Z-man. Pleaz explaine.


No - ISIS splines are not ANY issue with the exception of cross brand tolerance - which is also generally a non-issue. Key is to make sure to grease the interface or you get quick wear and tolerance issues. Octalink does not have this issue, not because it is superior, but because all parts are from the same Mfr.

ISIS goes Bye Bye because while it addressed the issue with square taper (tortion on spindle, spreading force cracking/shearing interface) - the larger diameter spindle necessitates smaller bearings - so they are moving them outside of the BB.

I am definitely a fan of starting to make larger BB Shells - or ream these bytches and at least go to a spanish BB setup.


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