The Good: The stem held the bars well, there were no issues with losing bolts or any other issues.
So far I haven’t had a Stem that held on to the handlebar as well as the Apex 35 stem, I went for many months from the middle of the winter to the spring without ever needing to do anything. It outperformed the Race Face Atlas Stem.
It might be the smart clamp design, maybe the materials used helped too, The stem is made of 2014 & 7075 alloy. it’s not only the bar that’s held on securely, but also the stem to the steerer-tube, so I have had I haven’t had issue with play in the headset, because the stem holds on so securely, the bolts don’t loosen fast like most stems I have used in the past, for example Race Face Atlas, I have experienced play in the headset & handle bars slipping, due to bolts getting loose, but never with Renthal Apex.
I of course thread locker, I use Loctite 243, which I have used on all of the stems I used.
The only times I made it loosen was without Loctite or not cured with big temperature change. The rental stems have great design, which allows low weight, But I did not notice any difference in stiffness & ride feels, from the Race Face Atlas Stem, which is heavily overbuilt. The stem is well machined, very smooth, no rough surfaces, but the edges are not rounded off to the section between steerer and handlebar are quite pointy, but this does not matter much, unless you slam your hand there, which is unlikely.
The Bad: The bolts could have better tolerances. But keep in mind my vernier might not be very accurate. BUt this is not an issue if you are careful.
The bolts showed signs of wear after the first installation, the tolerances between the tool and the bolts are quite loose, the diameter measurements are between 4.15 up to 4.24mm The park tools measurements are 3.99mm, the after few times of tightening the headset, I managed to damage the bolts, the bots became more damaged after tightening headset. The caliper might have not been very accurate, but I know the tool is not as snug fitting as I think they should be. I later used Teng tools bits, which fit better than Park Tool, but still there is a lot of play.
It might be that the bolts I got are just a manufacturing fluke for this batch, but there is no way for me to know for sure, but if all bolts are like this, this is a disappointment and should be addressed ASAP, but the Hex key only slipped once, I haven’t had issue since then.
