Truvativ bugs me

[free_rideman]

Anyways, I was all excited that I got the new Truvativ Hussefelt trials cranks made special for the Howitzer bb. I mean, the price was good since I got them for $120 new (total). So it was time to buy the bb, and they make this one bb for 68/73mm bb shells. You just use spacers to make up for the spindle's length. So I do what you're supposed to (one spacer on drive side, since I have a 73mm bb). Then I start tightening the drive side crank arm, and guess what? The stupid chain ring hits my chainstay yoke!!!!! And it isn't even tight yet!

There is nothing I can do, in terms of buying a new bb (at least I haven't seen any other ones), and I can't afford to spend more money on new cranks and bb.

The only idea I have is to give the drive side cranks to a machine shop, and let them shave some metal off from the mounting holes that the chan ring mounts to. This way it will bring the chain ring farther away from the frame.

This might be really stupid, but I wonder if I could do this with a disc brake tab facing tool? It should do the job unless the metal from the crank arm is too hard.

I hate myself for this...

[eturt9]

yep, that sounds about right. I just ran into that problem a couple days ago. Needed a 128 mm bb vs. the 118 i had. It's not truvativ's fault, they aren't the only ones with a 22 tooth chain ring. Plus the "norm" now is to run 18 teeth up front anyway.

before you think of machining metal, make sure your cranks don't hit your magura slave cylinders if you have them. Again, not bb's. fault.

spindle length is not 73, the spacers don't make up spindle length. They are to fit different bb shell widths. The spindle length is the total length of bb, in your case is probably 118 mm. Only fix is to get a bb 68/73mm with 128 mm length. They make this.

[WhiteRavenKS]

truvativ's idea of "trials" is a 22t ring on that 4bolt pattern. frame companies' idea of trials is front freewheels and tiny track cogs on threaded cranks. is it any wonder that the two dont jove on your bike?

swap the bb out for the longest spindle you can find, like a 128 as mentioned by eturt. if that doesnt fix it then you should probably put those nice cranks on another bike where they will continue to kick ass more effectively.

[free_rideman]

I think you are talking about standard isis bottom brackets. This is the new Howitzer bb. Basically isis with external bearings.

http://www.universalcycles.com/shopping/product_details.php?id=9462&category=346

The thing is, they try to kill to birds with one stone. They make one spindle and then if you have 68mm shell you need 3 spacers, and if a 73mm bb, you only use one spacer (each spacer is 2.5mm). I hope that clarifys the thing. See I can't buy any other type of bb. This is the only one for this crank that works.

:run:

Good idea on the chain ring size. I will check that out.

[Gaz]

This is exactly the problem that i had. my howitzer BB and hussefelt cranks from my other bike didn't fit because the granny ring touches the frame.

Solution is to by a longer spindle BB. My howitzer BB was 50mm chainline (measured from centre of frame to centre of middle chain ring). you need the 56mm chainline BB. (well they call it 56mm but itmight be labeled as 55 or 57.5, doesn't matter anyway as the wider bb means the chain ring clears the frame by 4 mm or so.)

This is effectly like buying a 128mm standard bb instead of a 118mm one as it shifts the cranks out 5mm each side.

And then all is good, apart from the fact that you might find like me that the cranks don't wedge on the the bb splines very good. I found that even doing the crank bolts up tight you could still pull the arms of the bb by hand and didn't need a crank puller. this was regardless of whether the bb was in the frame or not, so wasn't a spacer issue, just that truvativ seem to change their specs or something.

good luck....

[Gaz]

The thing is, they try to kill to birds with one stone. They make one spindle and then if you have 68mm shell you need 3 spacers, and if a 73mm bb, you only use one spacer (each spacer is 2.5mm). I hope that clarifys the thing. See I can't buy any other type of bb. This is the only one for this crank that works.

:run:

Good idea on the chain ring size. I will check that out.

This has nothing to do with the spacers. They actually are a good system but like you say don't move the cranks further out.

They do make a longer spindle BB though, it is just just measured by chainline, not spindle length like a regular internal bearing BB.

[Gaz]

pictures


http://www.observedtrials.net/otn3/P1010153.JPG

http://www.observedtrials.net/otn3/P1010154.JPG

[free_rideman]

Thanks for that help! A couple questions though. What year is your crank, compared to the bb? My cranks get stuck fairly easily on the spindle. I can't just pull them off.

I also am wondering about your chainline using the 56 chainline bb. With what gear does it line up in the back with? Somewhere in the middle of the cassette (I don't know if you run single speed or not)?

Thanks!

[Gaz]

Thanks for that help! A couple questions though. What year is your crank, compared to the bb? My cranks get stuck fairly easily on the spindle. I can't just pull them off.

I also am wondering about your chainline using the 56 chainline bb. With what gear does it line up in the back with? Somewhere in the middle of the cassette (I don't know if you run single speed or not)?

Thanks!

The cranks are from a 2006 Giant STP AU version so I presume they are 2006 cranks. On my previous BB, the 50mm chainline version, they wedge onto the BB nicely, just on the new BB they don't. It is rideable but unless you do the bolts up really tight you can feel slight movement. Maybe this isn't a problem, but it doesn't make me want to buy truvatvi again.

i run single speed so chainline doesn't matter to me. If you use an 8 or 9 speed cassette then it could be a problem I guess.

the following picture shows the rear cog. This lines up exactly with the granny ring at the front.


http://www.observedtrials.net/otn3/P1010150.JPG

[free_rideman]

Thanks for that picture! It lines up basically with the middle, so I should be good.

Oh, what bottom bracket width do you have and how many spacers? Remember that 3 spacers go on a 68mm bb, and only one goes onto a 73mm bb. If you didn't put enough spacers or something, then your spindle won't be positioned properly in the cups. (drive side gets priority: so its either 2:1 or 1:0 for the spacers, driveside stated first.

That is the only thing I can think of. Oh and did you grease everything a lot? The manul thingy says your a re supposed to grease the crap out of it.

I hope my doesn't do that... :noes: