In about fifteen years MTB became longer, lower and slacker: the reach and the wheelbase grew, the head angle slackened by several degrees, the effective seat angle got steeper (to keep climbing well) and the bottom bracket dropped. That's why an old bike feels nervous and cramped next to a modern one. But the old one wasn't worse at everything: it was more agile in slow terrain and more playful.
If you're coming from a bike from ten or fifteen years ago, the difference when you get on a modern one is brutal — and this is the explanation of why.
It's not nostalgia or marketing: the numbers really changed, and a lot. An "M" from 2010 and an "M" of today are almost two different bikes, even though both say trail.
| Number | Old (~15 years) | Modern |
|---|---|---|
| Head angle | ~71° (vertical) | ~65-66° (slack) |
| Reach (size M) | short | clearly longer |
| Wheelbase | short | quite a bit longer |
| Effective seat angle | ~73° (slack) | ~76-78° (steep) |
| Bottom bracket | higher | lower |
Typical indicative values to illustrate the trend; each brand and model varies. The direction of the change is what matters, not the exact number.
The main culprit is the vertical head angle with little trail: the steering turns lightning-fast and reacts to everything, which at slow pace is agility but on a fast descent becomes nervousness: the bike "dances" and demands constant correction. Add a short reach and wheelbase —less base of support, less room to move around standing— and you get that feeling of riding cramped and on the edge the moment the terrain gets serious. The modern one, slack and long, turns that same terrain into something calm.
The modern one doesn't win at everything. Old bikes, shorter and more vertical, were more agile in tight, slow corners, easier to maneuver on the spot and to lift the front wheel (manuals, dodging obstacles), and many climbed comfortably in a relaxed position. If your terrain is slow, technical and twisty, part of that old agility was a real virtue — and it's exactly what a very slack and long modern geometry sacrifices.
Vertical angle with little trail + short reach and wheelbase: it turns lightning-fast and reacts to everything. Agile slow, nervous fast.
More reach and wheelbase, slacker head angle, steeper effective seat angle, lower bottom bracket. Summary: long-low-slack.
No: more agile in slow terrain, easier to maneuver and to manual. The modern one wins descending; the old one, in playful riding.
Tell us your model and year and we'll tell you how its geometry stacks up against today's, and whether the jump suits you. Message us on WhatsApp
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