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Old 01-25-2022, 02:54 PM
gorkypl gorkypl is offline
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Join Date: Sep 2020
Posts: 48
57mm trail for gravel? HTA, trail and handling debate

Hello Paceliners,

I'm debating over geometry of my next gravel bike, and still need to decide about the headtube angle. Hope you can help.

My current CX/gravel has 72 degrees HTA paired with 50mm offset fork, which gives ~60mm trail with 38mm tyres.
This is already considered 'racy' geometry I think, but I am still not happy with the handling. The most annoying aspect is 'self-amplification' of the steering input - when I turn the handlebars, the bike feels like it falls to the side, and by this tries to turn even more. I'm not sure if it's called wheel flop or something else, but it's kinda annoying.

I don't have this feeling on my road bike, which has 73 degrees HTA and 45mm offset - these values give 57mm trail with 28mm tyres.
This bike does not amplificate the steering and feels much better in this aspect, but I think it may be too 'twitchy' if used for gravel in this exact configuration. Of course there may be other factors in play - compared to the other bike it has shorter wheelbase and lower BB, but I try to isolate the trail from the equation (if possible).

My thinking is that if I aim for 57mm trail on gravel (by steepening the HTA to 72.5 degrees and pairing it with 50mm fork offset), it should eliminate this self-amplification of turn, but wider tyres (no less than 38mm) will mute the steering a bit, so it will be not as nervous as the road bike is. Does it sound reasonable?

It may be worth noting that both on road and gravel bikes I currently use 120mm stem and 40cm handlebars. For this new bike I would go with 100-110mm stem and 42cm handlebars - not sure if this alone would noticeably change the steering (and into which direction).

I'd appreciate all insights
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