Fashion or Technology?

Nothing in mountain biking is truly new. Bikes have been around for a long time, and like Avril said, it’s all been done before.

Suspension? Yup, guys did that back in the late 1800s.

Curved seat tubes? Yeah, again, late 1800s. Those guys tried everything – clearly they were all over slack headtubes.

Dropper posts? Sure, we used to have that, it was called Hite-Rite.

So last year...

So last year…

Changes in mountain bikes are often about fashion just as much as they are about technology.  I recall reading about a racer asking Paul Turner if he had a set of the shiny new, gold Rock Shox Mag21s they could use, and when he said no, but he did have some old, black RS-1s, they declined. Old in this context is from last season, which is so five years ago.

What’s about to be the next big thing is wide rims. Ibis recently released a wheelset with 41mm wide rims. Typically, a mountain bike rim is in the 20mm range, so this is a big change.

I want to predict that 30mm will become the new standard, only because we’ve seen this happen before. Someone sticks their neck out, goes way out there. The rest of the industry acknowledges the change, but decides that you’ve gone too far, and picks something in between.

Like with headsets (1″ was too small, 1 1/4″ too big, but 1 1/8″ just right) and wheels (26″ too small, 29″ good but kinda big, 27.5″ just right).

Mavic MA-2

Mavic MA-2

Anyway, in the late 80’s, rims were wide and heavy. Till one day, Keith Bontrager grabbed a 40 hole Mavic MA-2 tandem rim out of the garbage, cut it down to 32 holes, and spliced it back together.

The “modern” MTB wheel was born – lightweight, and narrow.

I don’t think it was the width that Bontrager was looking for, but, that’s what the industry got. Of course because it was lighter and better, but partly because it was cooler. Just like that racer and the Mag 21s, everyone wanted the new hotness, and all rims got narrow.

It took till just a couple years ago that people started looking at wider rims, and here’s why;



My very crudely drawn diagram above depicts a tire on a narrow rim, A, and on a wider rim, B. Imagine that those two figures are sitting on a table, and you tried to push them over. A would tip over very easily, but B, not so much. Now imagine that A is a tubeless tire running only 22psi. It’s going to roll over every time you go around a corner because it just doesn’t have enough support.

Note that with “old” tube setups, you typically ran 40psi, which was enough pressure that the tire wouldn’t roll over. With low pressure, but a wide base, the modern tubeless tire has the support to stay upright.

Ibis wide rim

Ibis wide rim

And now, wide rims are the new hotness – but this time, there is some technology behind it.

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