Author Topic: Frame straightening - GMD Computrack?  (Read 1102 times)

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Offline Dunk

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Frame straightening - GMD Computrack?
« on: September 13, 2015, 11:02:46 AM »
Anyone have experience with GMD Computrack for checking and straightening a frame? Their marketing sounds pretty good. From what I can find there is a shop with a machine in Boston and maybe CT too, which would be within a 4-5 hour drive for me and is the closest shop I've found any reference to online that does frame repair. Other Computrack systems in TN, GA, FL much farther away but sounds like $150-$200 to check and anywhere from a few hundred to $2k or so to repair depending on how out of whack it is.

Went down and insurance suspected the frame may be bent. Relatively low speed high side after being struck by a car. Nothing appears majorly racked to my eye looking it over but there is some slight asymmetry in the rear triangles for passenger pegs and it did come down hard on right side bars and pegs. Have not taken a stringline or measurements yet as I'm recovering from injuries and not able to work with my hands in much capacity. Would like to have it checked. I have been down before on another K1 and that frame was definitely racked, I don't see that in this frame. Would prefer to have this checked and fixed if there's an issue, given K1s are kind of unique and any other 44 year old frame may be suspect too.

Anyone used a shop with a GMD Computrack machine for frame work? Thoughts and impressions? Pleased with the results? Any alternatives? Anyone specifically familiar with the shop in Milford CT or Bellingham MA? Anyone know a good frame shop somewhere closer than 4 hours to Philadelphia area in NJ/PA/DE?

Offline 754

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Re: Frame straightening - GMD Computrack?
« Reply #1 on: September 13, 2015, 11:06:49 AM »
I don't think the necks are very accurate right from the factory..at times I have read that they moved them sideways a bit to compensate for crowned roads... Not sure if that is true.
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Offline Dunk

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Re: Frame straightening - GMD Computrack?
« Reply #2 on: September 13, 2015, 06:07:09 PM »
I've also heard they weren't exactly dead on from the factory. Good enough tolerances when ramping up production. Mine is a late K1 I believe, when they started to get a little sloppy. Is there a way I can reasonably accurately check it with basic tools (i.e. no frame rack/table or fancy laser measuring machines)?

I did set up a stringline to check front to rear tire alignment (to a ruler, lines at width of rear tire, centered on front tire) and it's out maybe 1/16" at one of four points on the front tire and maybe 1/32 at another if at all, and seems to be just touching the front of the rear tire on each side. That tells me front and rear wheels are in line, but not necessarily that frame is straight? I'd think it would show something if it was majorly out of whack? Anything more I can do to determine if the head is straight or bends elsewhere?

Thought maybe putting a line center of front tire to center or rear and drop a plumb bob from center of frame midpoint and see if it lines up. Or do center of rear tire or frame at rear (swingarm mount?) center of frame farther up, and figure some sort of all thread and cones through the head to see if the all thread points to the centerline established from the frame and swingarm. Not sure, and that's all way beyond what I am capable of doing presently. Insurance is paying out on this so I'd prefer to just take it somewhere and know that's it's done right and all is well when they're through with it. It took me forever to do the stringline and I paying for it with some extreme pain in my back, shoulder and knee. Not sure what the road to recovery is paved with but it hurts.

Offline alacrity

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Re: Frame straightening - GMD Computrack?
« Reply #3 on: September 14, 2015, 03:01:15 PM »
Never used them, but Dr John's in Anaheim california has the secret sauce..
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