GSAstuto
Maximum Pace
- Oct 11, 2009
- 974
- 253
After a long and anticipated wait I finally got our first P&K Lie truing stand delviered. Actually I ordered a couple of them - but only one has arrived (another story). But this is enough to get me ranting and raving all over again!
One of the biggest hassles I have as a wheel builder is getting a wheel perfectly round AND perfectly in tension. Especially for carbon rims, where a few kgf either way on a spoke means you either start delaminating the rim, or start breaking spokes. So - there is minimal room for tolerance in building super tight and true wheels with carbon.
The P&K addresses these issues by allowing for wheel calibration + lateral and radial truing instructions within the same unit.
Step 1: Calibrate the wheel - including axle runout. This means to set the gauges (regardless of current wheel state) to absolute center - including the axle! From this absolute center - you can begin all truing steps.
Step 2: Run the wheel through a complete revolution to acquire maximum runout laterally and radially.
Step 3: Adjust ONLY the spokes at the max runout points to bring the wheel into perfect true.
Step 4: Cross check tension and repeat above (if required).
Since wheel runout is determined primarily by spoke tension and then secondarily by several other factors (including hub runout) , this method allows for very fast and super accurate of truing and then any post-truing compensation required to make the wheel 'perfect'. In essence, the builder knows exactly what's going on with the wheel from the absolute center point on out. So the wheel is trued as a 'whole' rather than simply lateral OR radial measurement at the end of the circle.
Of course you can mimick this with a standard truing stand (we do that all the time) , but it takes an exceedingly longer time to get it right - and too much 'feel' . With the P&K , I can teach a junior wheelbuilder exactly HOW to build a perfect wheel - and pretty much guarantee they'll get it right every time. I just set the recipe based on spoke tension and the truing happens 100% according to a known, numerical process that the builder can easily follow.
Very cool stuff. I have one of these now in our shop and will add more as they arrive. Once we get everything (and everyone) trained up , then we'll start offering micro-truing for wheels. I can get most alloy wheels within +/- .1mm and carbons +/- .25mm very quickly. If you followed the British Cycling Team at the Olympics - you may have caught the gist of a jab by the French questioning why the Brits immediately put their wheels in bags after each event suggesting that somehow the Brits were using 'non-standard' wheels.
The response by British Cycling was - 'well, yes we are --- they are round!' 'And we like to keep them that way!. Haha! Well, there's alot to this comment - because , a perfectly round wheel loses less energy in rotation than it's egg shaped counterpart. And, when milliseconds count on the track the last thing you want is to be rolling on a wobbly wheel!
From the road perspective - what this means is that having an evenly trued and round wheel lessens the effects of harmonic imbalance causing similar issues such as energy loss, high speed wobble and even spoke or hub failure with high tensioned wheels.
For the ultimate OCD wheel experience we could even true the wheel and tire as a unit! (This is in fact what the Olympic's Teams do) I don't have the nifty tire shaver yet - but that will be coming!
One of the biggest hassles I have as a wheel builder is getting a wheel perfectly round AND perfectly in tension. Especially for carbon rims, where a few kgf either way on a spoke means you either start delaminating the rim, or start breaking spokes. So - there is minimal room for tolerance in building super tight and true wheels with carbon.
The P&K addresses these issues by allowing for wheel calibration + lateral and radial truing instructions within the same unit.
Step 1: Calibrate the wheel - including axle runout. This means to set the gauges (regardless of current wheel state) to absolute center - including the axle! From this absolute center - you can begin all truing steps.
Step 2: Run the wheel through a complete revolution to acquire maximum runout laterally and radially.
Step 3: Adjust ONLY the spokes at the max runout points to bring the wheel into perfect true.
Step 4: Cross check tension and repeat above (if required).
Since wheel runout is determined primarily by spoke tension and then secondarily by several other factors (including hub runout) , this method allows for very fast and super accurate of truing and then any post-truing compensation required to make the wheel 'perfect'. In essence, the builder knows exactly what's going on with the wheel from the absolute center point on out. So the wheel is trued as a 'whole' rather than simply lateral OR radial measurement at the end of the circle.
Of course you can mimick this with a standard truing stand (we do that all the time) , but it takes an exceedingly longer time to get it right - and too much 'feel' . With the P&K , I can teach a junior wheelbuilder exactly HOW to build a perfect wheel - and pretty much guarantee they'll get it right every time. I just set the recipe based on spoke tension and the truing happens 100% according to a known, numerical process that the builder can easily follow.
Very cool stuff. I have one of these now in our shop and will add more as they arrive. Once we get everything (and everyone) trained up , then we'll start offering micro-truing for wheels. I can get most alloy wheels within +/- .1mm and carbons +/- .25mm very quickly. If you followed the British Cycling Team at the Olympics - you may have caught the gist of a jab by the French questioning why the Brits immediately put their wheels in bags after each event suggesting that somehow the Brits were using 'non-standard' wheels.
The response by British Cycling was - 'well, yes we are --- they are round!' 'And we like to keep them that way!. Haha! Well, there's alot to this comment - because , a perfectly round wheel loses less energy in rotation than it's egg shaped counterpart. And, when milliseconds count on the track the last thing you want is to be rolling on a wobbly wheel!
From the road perspective - what this means is that having an evenly trued and round wheel lessens the effects of harmonic imbalance causing similar issues such as energy loss, high speed wobble and even spoke or hub failure with high tensioned wheels.
For the ultimate OCD wheel experience we could even true the wheel and tire as a unit! (This is in fact what the Olympic's Teams do) I don't have the nifty tire shaver yet - but that will be coming!