[Kornphlake]

Is there some tool a shop can use to measure the alignment of a frame?


I ask because I've blown my shock enough this summer to think that maybe it is in fact my frame that needs some tweaking not the yahoos rebuilding the shock. I've got an ASX and I notice that if I unbolt the front shock mount and swing it out of the tabs it won't fit back in the mounting tabs unless I push it sideways slightly, maybe .010" I figured that if the frame was misaligned then with the shock removed I'd find some stickyness when moving the swingarm up and down, since the links are so short they'd be sensitive to misalignment. Maybe they are so short that they aren't sensitive to misalignemnt and I've just wallowed out the mounting holes??? I just wanted to know if there was any way to check the alignment of the frame, I already sent an email to Yeti, but they haven't responded yet. If it makes any differance I've got an '03 with the bronze bushings in the links rather than the sealed bearings, and the shorter stroke shock.

 

[oly]

I dont know about your specific frame, but ive had problems like that. With a "Faux" bar style frame. There was enough misalignment in the lower shock mount and upper plates that they had oversized the body spacers so the shock could be pulled over to match the upper link plates. There were still metal shavings on the frame... I got a new front tri and it was better., but not perfect, plus I also blew out bearings in the frame prematurly because of the alignment issue. I no longer ride that frame...

Also, .01" isnt that much. Are you sure thats the # you mean?? Not sure if you made a typo or not... I measured 4 sticky notes and they are about .009"-.01". My problem was like in the .1" to .150" range.

As far as a tool... park makes one for checking frames... its called the FAG-2 ...serious... http://www.parktool.com/tools/FAG_2.shtml . Im not sure how it works for checking your links in relation to everything. it looks like its more an overall check. They have pics... ask your LBS if they have a FAG-2....

 

[Showtime]

Check one of these out:
http://www.parktool.com/tools/FAG_2.shtml

Any well stocked shop should have one (I think they are relatively inexpensive too). They are really easy to use, just line it up on one side with your rear dropout and frame, then take it over to the other side of your bike, any difference will be aparent. Using it with a dualie is a bit more tricky sometimes, depending on how your pivots/shock/frame is setup, but there is usually a way to get a good measurement out of it.

 

[Showtime]

Damn... thats what I get for typing slowly....

 

[Curb Hucker]

I ask because I've blown my shock enough this summer to think that maybe it is in fact my frame that needs some tweaking not the yahoos rebuilding the shock.

what kind of shock is it, my friend was blowing 5ths on his SGS left and right under non-abusive riding too. he went through 5 re-builds and they finally gave him a new shock and its been holding up. so it still might be the shock, and yes .010" isnt much at all, i dont really think that would cause shock blowing side-loads

 

[buildyourown]

I used to work at a frame shop and did a lot of alignment checking and cold setting. The park tool doesn't help much. It will tell you that the rear wheel is inline with the seatpost and the headtube. Not really that helpful if you're trying to troubleshoot handling issues. Go to a good frame shop. There are lots in cali. Ask if they have an alignment table. This should be a large surface plate (preferably granite) with a post to mount the bb on. Then you can use height gauges to figure out where the headtube and seatube are in relation ship to each other. You can also see if the rear end lines up with the shock mount. You would be surprised how little force it takes to set an aluminum frame when the bb is fixed.
If you have trouble finding a properly equipped frame shop, let me know and I can do a query for you on private framebuilder's forum.

 

[oly]

T- we have one of those tables here.... or did...those are cool contraptions.... im sure its been pushed back into the dark corners somewhere to make room for the exercize area,......

 

[Kornphlake]

Also, .01" isnt that much. Are you sure thats the # you mean?? Not sure if you made a typo or not... I measured 4 sticky notes and they are about .009"-.01". My problem was like in the .1" to .150" range.

As far as a tool... park makes one for checking frames... its called the FAG-2 ...serious... http://www.parktool.com/tools/FAG_2.shtml . Im not sure how it works for checking your links in relation to everything. it looks like its more an overall check. They have pics... ask your LBS if they have a FAG-2....

I'm sure it's less than .050" it only takes a little force to get the shock where it needs to be, might be more than .010, possibly .030. I've got a set of calipers I can measure with when I get home, the eyeball estimate is something not much, but I'm worried if the swingarm is swinging at an angle to the shock mount the misalignment under full compression might be more like .100 or more.

what kind of shock is it, my friend was blowing 5ths on his SGS left and right under non-abusive riding too. he went through 5 re-builds and they finally gave him a new shock and its been holding up. so it still might be the shock, and yes .010" isnt much at all, i dont really think that would cause shock blowing side-loads

Yeah it's a 5th, I've had it rebuilt 3 times this summer, the second time it was DOA, this time seems to be about the same but they insist that every shock is tested before it leaves their service department. I have no reason not to believe them, it's costing them money and customer loyalty to have to repair a repaired shock more than once. The shock is over a year old so I don't know if they'll give me a new one, so far they have been good about warranteeing thier work though.

I used to work at a frame shop and did a lot of alignment checking and cold setting. The park tool doesn't help much. It will tell you that the rear wheel is inline with the seatpost and the headtube. Not really that helpful if you're trying to troubleshoot handling issues. Go to a good frame shop. There are lots in cali. Ask if they have an alignment table. This should be a large surface plate (preferably granite) with a post to mount the bb on. Then you can use height gauges to figure out where the headtube and seatube are in relation ship to each other. You can also see if the rear end lines up with the shock mount. You would be surprised how little force it takes to set an aluminum frame when the bb is fixed.
If you have trouble finding a properly equipped frame shop, let me know and I can do a query for you on private framebuilder's forum.

This sounds interesting. Now that I'm thinking about it I could measure the distance from the swingarm to the frame when uncompressed and then again when compressed and see if there's any misalignement, and do the same thing with the swing link. I haven't taken the time to see if the main pivot spindle is bent but it could be causeing a problem, maybe I'll check that out too. Does the frame have to be mounted to the surface plate at the bottom bracket or could I get creative and mount the dropouts to the surface plate. I kind of think that might work better for me. Should I really be worrying about this or should I let Yeti figure out what's wrong with it... It seems like a lot of jerry rigging to be able to do it on my own, I'd have to machine a mounting bracket of some sort. Would a frame builder typically charge me to check the alignment? If that's the case I'd rather let Yeti pay somebody in their shop to do it.

 

[Curb Hucker]

Yeah it's a 5th, I've had it rebuilt 3 times this summer, the second time it was DOA, this time seems to be about the same but they insist that every shock is tested before it leaves their service department. I have no reason not to believe them, it's costing them money and customer loyalty to have to repair a repaired shock more than once. The shock is over a year old so I don't know if they'll give me a new one, so far they have been good about warranteeing thier work though.

This sounds very much like what my friend went through, he had a DOA one too, it seemed no matter who re-built it, it would always blow. He talked with progressive for a while and came to the conclusion that his shock was a "lemon" and they eventually just gave him a new 04 5th, which hasnt yet blown. His was about 1.5 years old. Id look into talking to progressive about a new shock, or trying another brand.

 

[Kornphlake]

I'm working on the another brand thing, I could have bought a used vanilla RL for what I've spent on shipping back and forth, plus a few pesos for the push treatment. I don't want to successively blow a new shock because of a bent frame though.

As far as the shock being a lemon, that might be the case, I had to send it in 2 months after I bought the bike and I didn't ride the bike for the first month because I was waiting for a fork that got lost in the mail. Then about 8 months later it blew again after my bike and I had been in seperate states for 3 months, and only occasional weekend rides the remaining 5 months. My folks live in Hesperia, maybe I'll have to take a day off before christmas or thanksgiving and take my bike with the shock in and refuse to leave untill it works right.

Out of curiosity what was your friend's shock not doing? On mine the rebound won't adjust faster or slower no matter how far I turn the knob and eventually the rebound damping just dissapears, compression is the same way although I don't really notice it until it starts blowing through travel.

 

[Curb Hucker]

Out of curiosity what was your friend's shock not doing? On mine the rebound won't adjust faster or slower no matter how far I turn the knob and eventually the rebound damping just dissapears, compression is the same way although I don't really notice it until it starts blowing through travel.

his experiences were always similar. the piston seal never blew, oil would come from one, two, or three of his knobs and then adjustments went down the crapper

 

[buildyourown]

This sounds interesting. Now that I'm thinking about it I could measure the distance from the swingarm to the frame when uncompressed and then again when compressed and see if there's any misalignement, and do the same thing with the swing link. I haven't taken the time to see if the main pivot spindle is bent but it could be causeing a problem, maybe I'll check that out too. Does the frame have to be mounted to the surface plate at the bottom bracket or could I get creative and mount the dropouts to the surface plate. I kind of think that might work better for me. Should I really be worrying about this or should I let Yeti figure out what's wrong with it... It seems like a lot of jerry rigging to be able to do it on my own, I'd have to machine a mounting bracket of some sort. Would a frame builder typically charge me to check the alignment? If that's the case I'd rather let Yeti pay somebody in their shop to do it.

A good builder will charge you to do the check but not much. 15-30min of time to just check the frame. You don't have to use the bb a but if you are going to set the frame, it works best to start from the center and align out rather than aligning the from one end. Hard to explain in type. If you're just checking, you can use v-blocks and parallels if you know what you're doing.

 

[OGRipper]

Has Progressive given you any explanation for the problems with the shock? You'd think they could shed some light on what's going wrong and help you avoid what could be wasted time and effort checking out the frame.

But if you do check the frame, you definitely want to check how it changes as you move through the travel. Like you suspect it could be only look off by .01 at at full extension but get way worse deeper in the travel (example, that could happen if you've got a twisted pivot).

Doesn't the ASX have a swing link? That should do a lot to counter bad alignment and side loading, no? On the other hand, if the link mount is off, that could be part of the problem too...

Hmmm, it'll be interesting to see how this plays out, keep us posted.