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Currently riding a steel HT 29er on fairly technical SS and am considering a new Ti HT frame which sports a 14mm shorter top tube (effective) and a 10mm bigger head tube. Theoretically....how would this shorter top tube length and head tube size affect handling? I'm led to believe that the head tube length wont affect things other than raise the bars up a further 10mm. I think I can easily compensate for this by running flat bars and / or a flat / slight dropped stem. Everything else on the frame is (almost) identical in terms of frame sizing and geometry. The chainstay length is 3mm shorter too but I cant see that making a noticable difference.
it'll be easier to manual...
go back a couple of years i was running a 23top tube and a 135mm stem, which was normal, now the stem is 110 and the top tube has got a bit longer, which is the new norm, the reach is the same.
the difference?
Thing is, it is the rest of the geometry that matters as well.
it'll be easier to manual...
...but does that mean it'll be more 'wandery' when climbing?
Thinking about this after our discussion yesterday - it really won't move your centre-of-gravity much at all, maybe 5mm. That's not going to have any noticeable effect on how wandery the front end is I'd think.
Of course you could get back to exactly the same riding position (and same CoG) with a longer stem.
Everything else on the frame is (almost) identical in terms of frame sizing and geometry
really? same head angle, seat angle, bottom bracket drop etc?
are the 'effective' top tube lengths measured in the same way/at same points between the two frames?
14mm is not a lot, and if there are other difference then it's hard to say, I doubt that is the only difference between them.
How stretched out are you on the current frame?
If "not very" then beware as you might end up with a bike that's a pain to pedal any distance.
I'd want to be pretty certain about the geometry before I stumped up for a ti frame (not that I would anyway, but that's another kettle of worms).
You could consider slightly wider bars, rather than a longer stem, to keep your COG in a similar position.
Ben...I guess the only real way forward is to 'try' one out first!
I put a 70mm 6Deg stem on this morning which is 2mm away from my 90mm 0Deg stem in terms of ride height so I'll go for a blast later tonight and see how that feels from a 'stretched out' perspective. It'll sharpen the steering but I'm thinking it's a reasonable rough guide. I might actually end up liking this tweak anyway!
Anyone know of someone in the Glasgow area with a Van Nich Zion 29er in a 17.5" frame....?
Whats the seat tube angle on eahc? This could affect the tt length by 14 mm. And of course, you could run a layback seatpost to compensate if you needed to.
Seat tube angles on both are the same @ 73.5 deg. My planned frame simply has a 14mm shorter TT length. Didnt think about a layback....I always principly worked on the belief that seat position tweaked where your knee was in relation to the BB ie in front or behind. That being said, it will move my COG....