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aka Taprider
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Discussion Starter #1
So you go up a frame size to get longer reach (or the new version of your frame has longer reach but all the same seat tube and head angles etc.), but you use a shorter stem and less spacers so that your handlebars don't change position relative to your original set up.
and your new fork has less offset/rake,
so that your new front centre and wheelbase have not changed.

what handling changes can I expect?

when I need a new bike, I expect any choice available to have longer reach and shorter rake/offset fork
 

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Rippin da fAt
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8,267 Posts
Basics are that you changed caster angle, reach. Steering will be quicker. Since the stem is shorter with fewer spacers to keep the reach and stack same as it was, perhaps all you have accomplished is change to steering and handling feel.
 

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aka Taprider
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Discussion Starter #3 (Edited)
Ah! but the bike will have more trail, won't that cancel out or exceed the quicker steering effect of the shorter stem?
 

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Rippin da fAt
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Ah! but the bike will have more trail, won't that cancel out or exceed the quicker steering effect of the shorter stem?
That will be a real world thing to determine what the effect of one cancels the other thing. We can certainly project expectations then hit the trail, so to speak and learn the actual bike's configuration.
 

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MTB SOCAL
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So you go up a frame size to get longer reach (or the new version of your frame has longer reach but all the same seat tube and head angles etc.), but you use a shorter stem and less spacers so that your handlebars don't change position relative to your original set up.
and your new fork has less offset/rake,
so that your new front centre and wheelbase have not changed.

what handling changes can I expect?

when I need a new bike, I expect any choice available to have longer reach and shorter rake/offset fork
Assuming the same seat tube / head tube angles, it seems increasing reach should also increase front center (distance from bottom bracket to front hub).
 

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aka Taprider
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865 Posts
Discussion Starter #6
Assuming the same seat tube / head tube angles, it seems increasing reach should also increase front center (distance from bottom bracket to front hub).
yes, BUT, you use a fork with less offset/rake to cancel the increased reach of the frame
 

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MTB SOCAL
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1,449 Posts
yes, BUT, you use a fork with less offset/rake to cancel the increased reach of the frame
Changing fork offsets should not affect your frame's reach measurement.
 

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Wanna ride bikes?
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^ the last couple of posts could all be accurate but referring to different aspects of steering and geometry, not to mention fit.

In the first sentence of your post you're asking two different questions. Yes, modern bikes have a longer reach and shorter stem, but a Large is still a Large. Fork offset is a different question (and minor detail), and wheelbase is a different conversation and arguably more important.

Modern bikes/geo are different, mostly all for the better IMO. You don't need to try and match the numbers from your old/current bike, the new bike will be different, and that's OK!

So you go up a frame size to get longer reach (or the new version of your frame has longer reach but all the same seat tube and head angles etc.), but you use a shorter stem and less spacers so that your handlebars don't change position relative to your original set up.
and your new fork has less offset/rake,
so that your new front centre and wheelbase have not changed.

what handling changes can I expect?

when I need a new bike, I expect any choice available to have longer reach and shorter rake/offset fork
There's a lot of moving parts here. OP, it would help if you were more specific about the bikes you're comparing. Right now you're getting mixed responses, some factual and some opinion, because there's a lot of variables. Be specific and you will receive more accurate information.

I agree it's hard to change the reach/FC/WB/STA/HTA etc. without changing most/all of those other numbers. Usually one change changes 2-3 other aspects of geometry, not to mention ride characteristics and the feel of how a bike handles.
 

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aka Taprider
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Discussion Starter #10 (Edited)
There's a lot of moving parts here. OP, it would help if you were more specific about the bikes you're comparing. Right now you're getting mixed responses, some factual and some opinion, because there's a lot of variables. Be specific and you will receive more accurate information.
OK, does longer reach require less rake/offset?
or at what point do you get too much front centre?
you can keep moving your body forward to weight the front tire for flat low traction corners, but at some point you end up riding in an awkward position
Most of the short vs long offset comparisons I've read, use the same frame for each fork and don't correct for all the other variables such as bottom bracket to handle bar distance and angle (note: I'm not talking about distance to the saddle since someone will go on a tangent and start talking about seat tube angle)
Maybe there are other weird handling effects I'm not thinking of
 

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Wanna ride bikes?
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OK, does longer reach require less rake/offset?
or at what point do you get too much front centre?

you can keep moving your body forward to weight the front tire for flat low traction corners, but at some point you end up riding in an awkward position
Most of the short vs long offset comparisons I've read, use the same frame for each fork and don't correct for all the other variables such as bottom bracket to handle bar distance and angle (note: I'm not talking about distance to the saddle since someone will go on a tangent and start talking about seat tube angle)
Maybe there are other weird handling effects I'm not thinking of
No. FC numbers are getting longer with modern geo, and that's OK. There's lots of bikes with both 51 and 46 offset out there, there is no right or wrong. The difference is subtle and not dissimilar to a 67 degree HTA vs 68 HTA.

Again, we're speaking in generalizations. It would help if you were more specific.
 

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aka Taprider
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Discussion Starter #12
@OneSpeed thanks
I found some more recent articles where they agree the difference is subtle, and that for available range of offsets, when the front end is shrouded and the riders can't see what they are riding, they couldn't tell which offset they were riding
 

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Rippin da fAt
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Never confuse caster angle with rider position characteristics like reach or stack, evar!
These are completely separate topics!
 
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