Talk to me about geometry...
Basil Hume
Posts: 54
I ride a Pace RC305 with 130mm DT forks. This gives a head angle of 69.5 degrees and a seat angle of 72 degrees (I think).
I like the occasional road / touring ride and wonder what would happen if a stuck on a pair of rigid forks (which seem to come in at around 450mm length, as opposed to the 500+mm of the DT suspension forks). I presume this would steepen the angles and make them more akin to a short-travel hardtail or hybrid?
My main question is whether the bike would ride like a bag of nails with a short rigid fork?
I like the occasional road / touring ride and wonder what would happen if a stuck on a pair of rigid forks (which seem to come in at around 450mm length, as opposed to the 500+mm of the DT suspension forks). I presume this would steepen the angles and make them more akin to a short-travel hardtail or hybrid?
My main question is whether the bike would ride like a bag of nails with a short rigid fork?
Cotic Soul - Fox 32 RLC forks, XTR go, XT stop, Hope / DT wheels, Thomson / Easton / Hope finishing
Cotic >X< - 105 and SLX go, Avid stop, XT / Mavic disc wheels and Easton finishing
Cotic >X< - 105 and SLX go, Avid stop, XT / Mavic disc wheels and Easton finishing
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Comments
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IIRC the rough rule of thumb is 25mm A2C length = 1 degree change of head angle.
It'll be twitchy for sure.0 -
I guess that would make the frame effectively 71.5 head angle and 74 seat angle...
What sort of bikes run that geometry?Cotic Soul - Fox 32 RLC forks, XTR go, XT stop, Hope / DT wheels, Thomson / Easton / Hope finishing
Cotic >X< - 105 and SLX go, Avid stop, XT / Mavic disc wheels and Easton finishing0 -
XC bikes run somewhere around 71degree head angles but XC bikes are getting slacker head angles nowadays. You can get a head tube spacer that sits between the fork and lower headset to slacken things out a bit. Seat tube angle should be fine.
It's certainly doable.0 -
You could fit a set of the Exotic 29er forks, they're about 465mm axle to crown.Uncompromising extremist0
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You don't want them to be the same length a the sus fork anyway, as the fork will be sagged, and is working constantly.0
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Well, thanks to the pointers in this thread, I've just bought a set of Exotic 29er / 465mm carbon forks.
Interestingly, they were £99 including postage on eBay - but only £85 on CarbonCycles' own website, with free delivery. I'll report back on what they're like...
Together with some Conti Gator tyres and a Tubus Vega pannier rack (with adapter to fit rear wheel QR), I'm hoping that I'll be able to do manage some modest touring on the bike. If nothing else, I'll certainly have some options for a speedy commute.
The bike weighs 24.67lb with Conti Mountain King tyres and DT XMC130 forks. With the Gator tyres and Exotic forks this drops to 21.55lb by my calculations. Going singlespeed would get me down to 19.46lb!Cotic Soul - Fox 32 RLC forks, XTR go, XT stop, Hope / DT wheels, Thomson / Easton / Hope finishing
Cotic >X< - 105 and SLX go, Avid stop, XT / Mavic disc wheels and Easton finishing0 -
Once a man gets down to quoting 1/100ths of pounds, they are a mega weight weenie ;-)0
