How to Diagnose a Bent Frame | Get it Straight | Street Savvy

By Dave Moss, Photography by Amanda Kelly

Most of us have purchased a used motorcycle at some time and gone through the following analysis: Is it clean and well cared for? Continue. Are there service records available? Continue. Is this the original owner, and are they a genteel person? Continue. Is the asking price reasonable? Continue. Test-ride it and it rides beautifully. Negotiations must begin!

If the bike looks perfect, we don’t ask, “Has it been down?” But we should—every time. And if it has, we should have the bike measured to determine if it is straight. If the bike has a salvage title it must be measured—no excuses! With this wonderful weight-saving merry-go-round we are on these days with sportbikes, less weight means things bend easier. A simple slow-speed low-side can easily bend the fork tubes and lower triple clamp in one go.

There are many other areas of concern where due diligence should be exercised. Is the rear wheel aligned correctly? If not, you could see excessive wear on the sprocket teeth, drive chain, wheel bearings, cush-drive, axle and tire. Do you trust the swingarm marks provided by the manufacturer to be completely accurate, or do you use another method? How important do you think it is to have the rear wheel aligned perfectly? Important enough to take the time to make it right?

Does the rear wheel spin easily or show any evidence of an impact, such as a bent brake rotor? How many of us put the bike on the sidestand and check the wheels for trueness and the rotor to see if it is warped? Should you take the time to do that prior to parting with your hard-earned cash, or wait some months until you take the bike to the shop for new tires and are told by a mechanic that you have a problem?

It amazes me that we tend to gloss over this aspect of pre-purchase analysis. There have been many occasions when a new/old bike has come under my canopy for a suspension adjustment and the first question I ask the proud owner is, “Have you had it measured?” There’s a moment of glassy-eyed confusion, a clear and evident period of mental wrangling, and then a simple realization that we shouldn’t spend much time fine-turning the suspension until we know the bike is straight.

It is very empowering to know that your bike is truly ready to rock. Knowledge is indeed a powerful thing, and motorcycling is all about confidence. Riding with certainty is much more comforting than riding through adaptation.

By Dave Moss
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