Marzocchi MZ 3 vs. Recon 351 Air (travel) ??
SO today I went out and measured the travel between two forks.
The first is on my specialized hardrock pro hardtail. It says it only has 100mm of travel (Marzocchi MZ III) but it measures out to the same amount of travel as my RockShox Recon 351 Air which is 130mm (Trek Fuel EX7). I am confused :*<.
How did you measure the amount of travel? Did you just measure the amount of exposed stanchion or did you fully compress each fork and take a measurement? The amount of exposed stanchion does not always equal the amount of available travel. Also, I believe the travel on the Recon is adjustable with the use of internal spacers. Are you sure your Recon is set to 130mm?
cmktech, the easiest way....
to measure the travel of a fork is to get the axel to crown height of each fork from the manufacturers website and then measure each for in turn. Another way is to attach a zip tie to one stanchion on each fork and then remove all air or the top cap from above the coil spring and fully compess each fork. Then re-inflate or re-install the top cap and measure from the zip tie to the wiper seal. Either way is fairly accurate, but the ac height comparison is easier.
From the sounds of it, both forks are set for the same travel. As GTV8 noted, a 100mm travel fork will have MORE than 100mm of stanchion exposed. Usually around 5 to 20mm more than the actual travel. The extra 5 to 20mm of exposed stanchion is not usalbe travel as manufacturers usually leave a little extra so that the crown of the fork does not make contact with the wiper/seals at the top of the lowers under full compression. This would cause damage to them.
I don't have the exact AC height for the MZ III, but it should be right around 480 to 485mm for the 100mm travel version, add 20mm to that for the 120mm, that's plus or minus 5mm for margin of error.
The AC height for the Revelation is 478mm when set to 100mm of travel and 508mm when set to 130mm, again + or - 5mm. Those are manufacturers specs.
Another thing to keep in mind as well is that the axel to crown height varies quite a bit between manufacturers for a given travel. Marzocchi generally has the longest ac heights for a given travel. I had a Manitou for on a bike a while back, 80mm travel, that I replaced with a Marzocchi fork, also 80mm travel. The Zocch was a full 20mm longer than the Manitou for the same travel, and the Zocch had a full 10mm more exposed stanchion than the Manitou.
So what I think you are seeing here is a combination of different manufacturers specs for a given travel of fork. Rock Shox is known for having a fairly low AC height for a given travel on most of their forks. What I would do is use the zip tie method to measure travel for each fork and then compare AC heights. My guess is that the AC height of the Zocch is pretty close to that of the Revelation even though the Rev has more travel. It's possible that a mistake was made in set up of the Rev before it was shipped to Trek, and it is set for 100mm of travel, but I doubt it. Anyway, do some more measurements and see what you come up with.
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