3 Keys to STRADA tire clearance

How big is best?

The most common questions about the STRADA regard tire clearance. What fits, is there enough clearance with the frame, what set-up is fastest and what if the tire picks up a little debris? Here are the answers.

1) What tire width do you recommend?

We have a group of pros cyclists (who in their daily lives ride for various teams on different brands) and “regular” riders test all our products, including the STRADA. In this case, the testing also included various tire sizes. The main two tires we tested were effectively 27mm and 30mm wide. The result was a bit opposite to what I had expected.

All the pros – without exception – preferred the 30mm tire. They noticed no difference in speed, which makes sense because there isn’t any on the STRADA – our wind tunnel testing has also shown there is no drag penalty for the bigger tire due to the frame design. But they all chose the 30mm tire based on a slight benefit in comfort. Usually the comments were something like “very comfortable with the 27mm, extremely comfortable with the 30mm, and a strange sensation to feel that the frame is so stiff but the ride is not”.

Some of the pros noticed that occasionally the bigger tire would pick up some debris from the road (most never even mentioned this), but even those who did notice didn’t think much of it and concluded that “the same happens on my TT bike”. Indeed, if you want a bike to be fast in real life, not just in the marketing claims, a tight spacing between tire and frame is key and the STRADA has the same clearance as the fastest TT bikes have had for 20 years.

For the regular riders, the result was a bit more varied. About half of these riders preferred the 30mm, the other half the 27mm tire. Comments were either similar to the pros, or they were balancing the tire width and the occasional debris pick-up with “I can already feel the comfort of the 27mm, why go wider?”

A third group that has ridden the STRADA quite extensively by now is the press. They seem in general to lean more towards the “pro view” of wider is better, with some notable exceptions. We were disappointed with some comments that the clearance is too tight when you run the STRADA with the biggest tire AND inflate them to a pressure totally unsuitable for such a tire, but everybody is entitled to their own opinion and the STRADA is not for everybody. People who want a road bike with the most tire clearance can do no better than the 3T EXPLORO.

It’s a bit strange that the pros moved more towards comfort than the other riders, I would have expected the opposite, but that’s how it went. In the end, we set the official recommendation for the actual, measured tire width at 28mm. For sure the pros will continue to use the 30mm (as will I), but the 28mm is a good middle ground for very good comfort and more clearance to reduce debris pickup. And of course a 25mm or traditional 23mm tires fits too, there’s just no real benefit to it.

2) So, which brand works well?

The key here is not so much the brand as the actual tire measurement. On a 3T Discus C60 TEAM wheel, a “28mm” Schwalbe Durano actually measures 25.7mm wide, a “28mmm” Pirelli Velo 4s is 29.4mm and a “28mm” Continental GP 4000S II is 30.5mm.

So almost a 5mm difference in width between tires that are nominally identical. To make it even more confusing, if you measure 10 tires of each of these, you will find some variation too, usually 1mm or so but with some brands much more.

Some of this is unavoidable, tire production is complicated and there are variations due to rubber compound, die wear, factory temperature, tire wear, etc, etc. Furthermore, the actual tire width also depends on the rim width and the tire makers don’t control what wheel you choose.

One of the reasons is a bit more cynical though. Tire manufacturers know most consumers just look at the label and don’t actually measure tires widths. If they want more comfort, they go from a tire labeled 23mm to a 25mm, or from a 25mm to a 28mm. But tire brands also know that consumers care a lot about weight, and do measure that. So if they take a narrow tire (which is lighter) and label it wider, they win those weigh scale battles and few people figure out they didn’t really buy the width they thought.

Most manufacturers do this, on a normal rim most tires measure more narrow than the label indicates. Continental and Pirelli are two exceptions, a lot of their tires measure wider than indicated. The 30mm tires we test most with are the GP 4000 and Pirelli Velo 4s in 28mm nominal width. The “27mm tire” group for our testing included the 25mm nominal width GP 4000, a few Vittorias and the aforementioned Schwalbe.

It is also important to note that the measured tire width is also dependent on the rim width. The wider the internal width of the rim, the wider the tire will become. If you put that 28mm Conti on a traditional rim with 17mm internal width, it will probably measure close to its official width. Bottomline, figure out how much clearance you want, then measure the tire you like on the actual rim you want to use.

3) Will the paint on my frame scratch?

To paraphrase: “the first scratch is the deepest”. All bikes get scratched and bikes with tight tire clearances, whether they are TT or road bikes, will develop some scratches in those cutout areas. However, most road tires do not have a lot of profile, so they don’t pick up very much. But if you ride it will happen. Luckily these scratches are per definition in areas you rarely see, as they are closely covered by the tire.